$1 billion BMS Ooops... [Archive]

kinsell

February 25th 21, 02:49 PM

On 2/24/21 9:22 PM, Eric Greenwell wrote:
> Dave Nadler wrote on 2/24/2021 6:08 PM:
>> On 2/24/2021 8:55 PM, kinsell wrote:
>>> On 2/24/21 4:13 PM, Dave Nadler wrote:
>>>> On 2/24/2021 4:51 PM, Darryl Ramm wrote:
>>>>> On Wednesday, February 24, 2021 at 1:42:01 PM UTC-8,
>>>>> wrote:
>>>>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
>>>>>>
>>>>>> Discuss amongst yourselves...
>>>>>
>>>>> Dave, it's time for you to stop complaining and just admit electric
>>>>> is simple.
>>>>
>>>> You're absolutely right Darryl!
>>>> After all, how hard could it be???
>>>
>>> Simple and ultra reliable.Â* You gonna be dragging your old faithful
>>> Antares down to the Seniors this year?
>>
>> After it failed during the last two comps I took it to?
>> Drive for days, fly a few times, then drive for days home after it
>> breaks?
>> I don't think so...
>>
>> Anyway, no vaccination yet so no travel in any case.
>
> The Antares was a bold effort, perhaps too bold, and by now, it's an old
> effort. No point in holding it up as an example anymore. Now, all the
> manufacturers have electric gliders, and Solo has added electric systems
> to their sailplane power business. Electric isn't the coming thing any
> more: it's here. The next milestone will be passed when they start
> selling more electrics than ICEs.
>

I see another Silent 2 just popped up on the market, that makes four
plus one recently sold. Garret suggests you might want to aerotow or
winch launch to conserve battery power. When I see these things with a
dozen hours on them up for sale, it suggests that the owners aren't that
thrilled with what they got for their money.

Dave Nadler

February 25th 21, 03:56 PM

On 2/25/2021 9:49 AM, kinsell wrote:
> I see another Silent 2 just popped up on the market, that makes four
> plus one recently sold.Â* Garret suggests you might want to aerotow or
> winch launch to conserve battery power.Â* When I see these things with a
> dozen hours on them up for sale, it suggests that the owners aren't that
> thrilled with what they got for their money.

The Silent 2 is an interesting bird.
I've got friends that love it, and others that have sold it on.
Some owners have had to replace battery packs, newer packs
are reported OK - but this is 2nd or 3rd hand info.
More importantly, its got very limited energy, so if you
self-launch, not much in the tank to get home.
Because of its limited performance, you can't just skip
over gaps that higher performance machines take for granted,
and a bit of headwind is a big obstacle.

So, if it can do what you need with your weather and site
constraints, great! But work through carefully whether it
meets your needs.

FWIW...
Best Regards, Dave

Hank Nixon

February 25th 21, 04:01 PM

On Wednesday, February 24, 2021 at 4:42:01 PM UTC-5, wrote:
> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> Discus amongst yourselves...

The market wants:
Fast charge for convenience
Safety
Long life for low cost of ownership
It is possible to get the send two if one compromises on the first.
Can't have all.
Balancing packs requires time.
Unbalanced packs fail or die sooner.
Reality
UH

Eric Greenwell[_4_]

February 25th 21, 04:45 PM

kinsell wrote on 2/25/2021 6:49 AM:
> On 2/24/21 9:22 PM, Eric Greenwell wrote:
>> Dave Nadler wrote on 2/24/2021 6:08 PM:
>>> On 2/24/2021 8:55 PM, kinsell wrote:
>>>> On 2/24/21 4:13 PM, Dave Nadler wrote:
>>>>> On 2/24/2021 4:51 PM, Darryl Ramm wrote:
>>>>>> On Wednesday, February 24, 2021 at 1:42:01 PM UTC-8, wrote:
>>>>>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
>>>>>>> Discuss amongst yourselves...
>>>>>>
>>>>>> Dave, it's time for you to stop complaining and just admit electric is simple.
>>>>>
>>>>> You're absolutely right Darryl!
>>>>> After all, how hard could it be???
>>>>
>>>> Simple and ultra reliable.* You gonna be dragging your old faithful Antares down to the
>>>> Seniors this year?
>>>
>>> After it failed during the last two comps I took it to?
>>> Drive for days, fly a few times, then drive for days home after it breaks?
>>> I don't think so...
>>>
>>> Anyway, no vaccination yet so no travel in any case.
>>
>> The Antares was a bold effort, perhaps too bold, and by now, it's an old effort. No point in
>> holding it up as an example anymore. Now, all the manufacturers have electric gliders, and
>> Solo has added electric systems to their sailplane power business. Electric isn't the coming
>> thing any more: it's here. The next milestone will be passed when they start selling more
>> electrics than ICEs.
>>
>
> I see another Silent 2 just popped up on the market, that makes four plus one recently sold.
> Garret suggests you might want to aerotow or winch launch to conserve battery power.* When I
> see these things with a dozen hours on them up for sale, it suggests that the owners aren't
> that thrilled with what they got for their money.

It would be instructive to discuss the reasons with the people selling the Silents. My only
contact with one is Jeff Banks' Silent. We flew together for a week out of Richfield, UT, last
year. He likes it, self-launched every flight, and had good flights. He also flew out of Heber,
Nephi and Dick Stout airfields in 2020. You can check the OLC for his flights in 2018, 2019 and
2020. Also, 2021 - first flight of the year at Seminole.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

kinsell

February 25th 21, 04:50 PM

On 2/25/21 9:01 AM, Hank Nixon wrote:
> On Wednesday, February 24, 2021 at 4:42:01 PM UTC-5, wrote:
>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
>> Discus amongst yourselves...
>
> The market wants:
> Fast charge for convenience
> Safety
> Long life for low cost of ownership
> It is possible to get the send two if one compromises on the first.
> Can't have all.
> Balancing packs requires time.
> Unbalanced packs fail or die sooner.
> Reality
> UH
>

Just reading about the Lilium electric air taxi in Forbes, they want to
draw 1.2 megawatts from the batteries for 60 seconds for vertical
takeoff and transition to forward flight.

You can do that sort of thing for 3 seconds in a Tesla for Ludicrous
mode, but 60 seconds can fry the batteries in the air taxi.

Tesla has 4000 small cylindrical cells, with a manifold in contact with
all of them, with pumped liquid cooling to allow high charge and
discharge rates.

Most electric gliders just use big pouch cells, a lot of people just
don't understand the implications of that.

Lilium has raised 400 odd million bucks in funding, looking more like a
pipe dream all the time. Ditto for that Alice thingie, but they've only
burned 200 mil.

Tango Eight

February 25th 21, 05:32 PM

On Thursday, February 25, 2021 at 11:50:46 AM UTC-5, kinsell wrote:
> Just reading about the Lilium electric air taxi in Forbes, they want to
> draw 1.2 megawatts from the batteries for 60 seconds for vertical
> takeoff and transition to forward flight.

1.21 Gigawatts for 60 microseconds and you can go back in time. Or you'll be history. Or something like that.

Now, where did I leave my Segway...

There's no law saying that investors have to be smart.

T8

Herbert kilian

February 25th 21, 05:52 PM

On Thursday, February 25, 2021 at 10:50:46 AM UTC-6, kinsell wrote:
> On 2/25/21 9:01 AM, Hank Nixon wrote:
> > On Wednesday, February 24, 2021 at 4:42:01 PM UTC-5, wrote:
> >> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> >> Discus amongst yourselves...
> >
> > The market wants:
> > Fast charge for convenience
> > Safety
> > Long life for low cost of ownership
> > It is possible to get the send two if one compromises on the first.
> > Can't have all.
> > Balancing packs requires time.
> > Unbalanced packs fail or die sooner.
> > Reality
> > UH
> >
> Just reading about the Lilium electric air taxi in Forbes, they want to
> draw 1.2 megawatts from the batteries for 60 seconds for vertical
> takeoff and transition to forward flight.
>
> You can do that sort of thing for 3 seconds in a Tesla for Ludicrous
> mode, but 60 seconds can fry the batteries in the air taxi.
>
> Tesla has 4000 small cylindrical cells, with a manifold in contact with
> all of them, with pumped liquid cooling to allow high charge and
> discharge rates.
>
> Most electric gliders just use big pouch cells, a lot of people just
> don't understand the implications of that.
>
> Lilium has raised 400 odd million bucks in funding, looking more like a
> pipe dream all the time. Ditto for that Alice thingie, but they've only
> burned 200 mil.
Right on, Dave. I want to see just one of these pipe-dream machines get a standard airworthiness cert. with the OK for carrying passengers, just one. Just like fusion power (and Trump's healthcare plan), it's only a short few years away, I guess.

Dan Marotta

February 25th 21, 08:34 PM

Oh that is so last decade. I've got an InMotion V11 instead, and the
bruises to prove it!

Dan
5J

On 2/25/21 10:32 AM, Tango Eight wrote:
> Now, where did I leave my Segway...

Darryl Ramm

February 25th 21, 10:38 PM

On Thursday, February 25, 2021 at 12:34:46 PM UTC-8, Dan Marotta wrote:
> Oh that is so last decade. I've got an InMotion V11 instead, and the
> bruises to prove it!
>
> Dan
> 5J
> On 2/25/21 10:32 AM, Tango Eight wrote:
> > Now, where did I leave my Segway...

Electric unicycle that's adventurous as one of us old folks.... oh remembers Dan has a gyrocopter... :-)

Dave Nadler

February 26th 21, 01:07 AM

On 2/24/2021 11:22 PM, Eric Greenwell wrote:
> ...Electric isn't the coming thing any
> more: it's here. The next milestone will be passed when they start
> selling more electrics than ICEs.

Eric, you've been drinking the Cool-Aid.
As I did once.
You're bringing your new electric machine to the Seniors, right?
And I do mean THIS year...

kinsell

February 26th 21, 01:30 AM

On 2/25/21 6:07 PM, Dave Nadler wrote:
> On 2/24/2021 11:22 PM, Eric Greenwell wrote:
>> ...Electric isn't the coming thing any more: it's here. The next
>> milestone will be passed when they start selling more electrics than
>> ICEs.
>
> Eric, you've been drinking the Cool-Aid.
> As I did once.
> You're bringing your new electric machine to the Seniors, right?
> And I do mean THIS year...

I noticed one of the other Silent 2 Electro owners was fishing around to
buy an ASH31Mi, a gas guzzling Schleicher product. Grass is always
greener on the other side.

Maybe Eric and that guy could work out a swap, then they'd both have
their dream ships :-)

G K

February 26th 21, 02:28 AM

> Right on, Dave. I want to see just one of these pipe-dream machines get a standard airworthiness cert. with the OK for carrying passengers, just one.

- I know of one being close. Look up Joby.

Just like fusion power (and Trump's healthcare plan), it's only a short few years away, I guess.

- Kamala has a health plan for you Herb.
Unfortunately, You and Me as white males only get to pay for it, but Hey now!
It's a true realization of Marx&Engel's dreams and it covers the entire Central America.

Best,
GK

Eric Greenwell[_4_]

February 26th 21, 04:02 AM

Dave Nadler wrote on 2/25/2021 5:07 PM:
> On 2/24/2021 11:22 PM, Eric Greenwell wrote:
>> ...Electric isn't the coming thing any more: it's here. The next milestone will be passed
>> when they start selling more electrics than ICEs.
>
> Eric, you've been drinking the Cool-Aid.
> As I did once.
> You're bringing your new electric machine to the Seniors, right?
> And I do mean THIS year...

Even on the original, pre-Covid schedule, it would not have been ready for the Seniors. And
consider this: my current motorglider, the ASH26E, was delivered a year late by Schleicher, so
by that standard, GP still has until Feb. 2022 to get the new glider to me :^)

There are a lot of FES gliders out there now, and with all the manufacturers offering them,
there will be many more. The more powerful electrics with mast mounted propellers are also
offered by all the manufacturers, and many pilots that think the FES gliders are appealing but
marginal will be ordering these new gliders.

I think you will see a lot of Kool-Aid drinkers behind the Schleicher, Schempp-Hirth, and
Jonkers booths at the SSA convention in 2022, all offering what you saw - and desired - in the
Antares years ago. They won't make the same mistakes that Lange made.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Dan Marotta

February 26th 21, 04:58 PM

Yes, and I've been laid up for the past week after a horrific spill. My
helmet and pads protected skin and skull, but not the ribs from a good
bruise. Now it hurts to laugh (really) and I'm impatiently waiting for
the pain to subside so I can mount up again. Pretty sure I can fly the
gyro without problems, but getting in and out of the thing will hurt...

Dan
5J

On 2/25/21 3:38 PM, Darryl Ramm wrote:
> On Thursday, February 25, 2021 at 12:34:46 PM UTC-8, Dan Marotta wrote:
>> Oh that is so last decade. I've got an InMotion V11 instead, and the
>> bruises to prove it!
>>
>> Dan
>> 5J
>> On 2/25/21 10:32 AM, Tango Eight wrote:
>>> Now, where did I leave my Segway...
>
> Electric unicycle that's adventurous as one of us old folks.... oh remembers Dan has a gyrocopter... :-)
>

Dan Marotta

February 26th 21, 09:42 PM

Went to the airport today. Wind was 40 degrees off at 27 gusting 33
kts. The gyro POH says 60 kmh is the max so I just helped my wife train
on her unicycle.

Dan
5J

On 2/26/21 9:58 AM, Dan Marotta wrote:
> Yes, and I've been laid up for the past week after a horrific spill.Â* My
> helmet and pads protected skin and skull, but not the ribs from a good
> bruise.Â* Now it hurts to laugh (really) and I'm impatiently waiting for
> the pain to subside so I can mount up again.Â* Pretty sure I can fly the
> gyro without problems, but getting in and out of the thing will hurt...
>
> Dan
>
> On 2/25/21 3:38 PM, Darryl Ramm wrote:
>> On Thursday, February 25, 2021 at 12:34:46 PM UTC-8, Dan Marotta wrote:
>>> Oh that is so last decade. I've got an InMotion V11 instead, and the
>>> bruises to prove it!
>>>
>>> Dan
>>> 5J
>>> On 2/25/21 10:32 AM, Tango Eight wrote:
>>>> Now, where did I leave my Segway...
>>
>> Electric unicycle that's adventurous as one of us old folks.... oh
>> remembers Dan has a gyrocopter... :-)
>>

Dave Nadler

February 26th 21, 10:14 PM

On 2/25/2021 9:28 PM, G K wrote:
> - I know of one being close. Look up Joby.

https://www.youtube.com/watch?v=4wbFw165ar0&feature=emb_title

Dave Nadler

February 26th 21, 10:16 PM

On 2/25/2021 11:02 PM, Eric Greenwell wrote:
> Dave Nadler wrote on 2/25/2021 5:07 PM:
>> On 2/24/2021 11:22 PM, Eric Greenwell wrote:
>>> ...Electric isn't the coming thing any more: it's here. The next
>>> milestone will be passed when they start selling more electrics than
>>> ICEs.
>>
>> Eric, you've been drinking the Cool-Aid.
>> As I did once.
>> You're bringing your new electric machine to the Seniors, right?
>> And I do mean THIS year...
>
> ...They won't make the same mistakes that Lange made.

Except they already have.
GP delivered and then undelivered to USA a good example.

Dgtarmichael

February 26th 21, 10:24 PM

On Friday, February 26, 2021 at 3:42:33 PM UTC-6, Dan Marotta wrote:
> Went to the airport today. Wind was 40 degrees off at 27 gusting 33
> kts. The gyro POH says 60 kmh is the max so I just helped my wife train
> on her unicycle.
>
> Dan
> 5J
> On 2/26/21 9:58 AM, Dan Marotta wrote:
> > Yes, and I've been laid up for the past week after a horrific spill. My
> > helmet and pads protected skin and skull, but not the ribs from a good
> > bruise. Now it hurts to laugh (really) and I'm impatiently waiting for
> > the pain to subside so I can mount up again. Pretty sure I can fly the
> > gyro without problems, but getting in and out of the thing will hurt...
> >
> > Dan
> >
> > On 2/25/21 3:38 PM, Darryl Ramm wrote:
> >> On Thursday, February 25, 2021 at 12:34:46 PM UTC-8, Dan Marotta wrote:
> >>> Oh that is so last decade. I've got an InMotion V11 instead, and the
> >>> bruises to prove it!
> >>>
> >>> Dan
> >>> 5J
> >>> On 2/25/21 10:32 AM, Tango Eight wrote:
> >>>> Now, where did I leave my Segway...
> >>
> >> Electric unicycle that's adventurous as one of us old folks.... oh
> >> remembers Dan has a gyrocopter... :-)
>

I don't understand the electric bashing. It's still a new and developing technology. By comparison I've never heard of an ICE motorglider that didn't have its own set of problems. Carburetors that don't tune, no parts for certain models, some that occasionally start fire, many that don't start at all. They're so bad that we're warned to NEVER expect them to work for a relight. You have to have them out and running before the pure gliders are even getting serious about looking for the spot to land. I'm a purest by nature and budget, but I'd never count out the future of electrics in soaring.. Mr. Nadler hate on Lange all you want it was Schemp-Hirth that almost killed you.

Doug
W24

Eric Greenwell[_4_]

February 26th 21, 11:17 PM

Dave Nadler wrote on 2/26/2021 2:16 PM:
> On 2/25/2021 11:02 PM, Eric Greenwell wrote:
>> Dave Nadler wrote on 2/25/2021 5:07 PM:
>>> On 2/24/2021 11:22 PM, Eric Greenwell wrote:
>>>> ...Electric isn't the coming thing any more: it's here. The next milestone will be passed
>>>> when they start selling more electrics than ICEs.
>>>
>>> Eric, you've been drinking the Cool-Aid.
>>> As I did once.
>>> You're bringing your new electric machine to the Seniors, right?
>>> And I do mean THIS year...
>>
>> ...They won't make the same mistakes that Lange made.
>
> Except they already have.
> GP delivered and then undelivered to USA a good example.

Please note GP wasn't on my list of booths. I do expect the manufacturers that have been
building gliders for decades to have fewer stumbles, and I don't think it is an indictment of
the technology if a startup has problems delivering on time. It is always an extra risk to
order a glider that is not in production yet (also the case when I ordered my ASH26E), and even
riskier when it's a new manufacturer (GP, Lange), but for me, the GP15 is still a more
desirable glider than what the major manufacturers are offering.

So, I will repeat: Schleicher, Schmepp-Hirth, and Jonkers will not make the same mistakes Lange
made (perhaps I should add LAK and Pipistrel to the list).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Martin Gregorie[_6_]

February 26th 21, 11:43 PM

On Fri, 26 Feb 2021 17:14:23 -0500, Dave Nadler wrote:

> On 2/25/2021 9:28 PM, G K wrote:
>> - I know of one being close. Look up Joby.
>
> https://www.youtube.com/watch?v=4wbFw165ar0&feature=emb_title

Their timescale, payload and performance looks very similar to Vertical
Aerospace, https://vertical-aerospace.com/ except that VS are aiming for
a bit less range and speed, probably because they are looking at the UK
market rather than the US with its greater ride distances.

Do any of you know what sort of landing/takeoff patch these eVTOL air
taxis are planning to operate from, i.e. helipads to something more al
fresco such as carparks or schoolyards or are they planning to run door
to door operations, which may be a quite limited by availability of
landing areas in cities outside the US - unless, of course, their target
market is just airfield to airfield traffic.

I ask, because, although I've been dimly aware of efforts to build eVTOL
air taxis for a year or two, I've seen absolutely nothing about where
they expect to land when dropping off & picking up fares.

--
Martin | martin at
Gregorie | gregorie dot org

[email protected]

February 27th 21, 04:25 PM

An uncontained battery failure is as bad as an uncontained engine failure (car, airplane, or glider). Any potentially unstable battery like most Lithium chemistries should be in a safety container that will either contain or exhaust the fire, explosion, or heat. I would feel a lot better if the batteries were in a sealed stainless box with appropriate vents to the outside of vehicle.
Wit HZ

Moshe Braner

February 27th 21, 04:48 PM

On 2/27/2021 11:25 AM, wrote:
> An uncontained battery failure is as bad as an uncontained engine failure (car, airplane, or glider). Any potentially unstable battery like most Lithium chemistries should be in a safety container that will either contain or exhaust the fire, explosion, or heat. I would feel a lot better if the batteries were in a sealed stainless box with appropriate vents to the outside of vehicle.
> Wit HZ

I feel a bit nervous about carrying a "USB power bank" in the glider,
which includes a not-tiny lithium battery of the dangerous type. As for
the yuuuge batteries needed for electrically propelled gliders, I think
I'd wait for safer battery chemistry. LiFePO4 batteries are a lot
safer, and their energy density - and price - are being improved so that
they can compete with other types of lithium batteries. They are
already used in some electric cars.

Eric Greenwell[_4_]

February 27th 21, 07:49 PM

Moshe Braner wrote on 2/27/2021 8:48 AM:
> On 2/27/2021 11:25 AM, wrote:
>> An uncontained battery failure is as bad as an uncontained engine failure (car, airplane, or
>> glider). Any potentially unstable battery like most Lithium chemistries should be in a safety
>> container that will either contain or exhaust the fire, explosion, or heat. I would feel a
>> lot better if the batteries were in a sealed stainless box with appropriate vents to the
>> outside of vehicle.
>> Wit HZ
>
> I feel a bit nervous about carrying a "USB power bank" in the glider, which includes a not-tiny
> lithium battery of the dangerous type.* As for the yuuuge batteries needed for electrically
> propelled gliders, I think I'd wait for safer battery chemistry.* LiFePO4 batteries are a lot
> safer, and their energy density - and price - are being improved so that they can compete with
> other types of lithium batteries.* They are already used in some electric cars.
>
You should look at the Jonkers JS3 RES electric self-launcher using LiFePo batteries. It's the
only one I know of using that kind of battery.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[email protected]

February 27th 21, 09:19 PM

Eric,

I think that is probably a typo mistake, the voltage range and capacity is typical for 3000-3500 mAh li-ion cell.

Eric Greenwell[_4_]

February 27th 21, 11:07 PM

wrote on 2/27/2021 1:19 PM:
> Eric,
>
> I think that is probably a typo mistake, the voltage range and capacity is typical for 3000-3500 mAh li-ion cell.
> It's a bit awkward to drill down to it, so here's a short cut. Go to this page:
https://jonkersailplanes.co.za/res-system/

Then scroll to the section with this:

Battery specification

Battery type EMECTRIC 96-4 400V
Battery configuration 96S4P LiFePo
Battery Voltage 270V-400V
Capacity per battery 4.7kWh
Battery Weight: 22kg (48.5 lbs)
Maximum number of batteries 2

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[email protected]

February 27th 21, 11:30 PM

El sÃ¡bado, 27 de febrero de 2021 a la(s) 20:07:36 UTC-3, Eric Greenwell escribiÃ³:
> wrote on 2/27/2021 1:19 PM:
> > Eric,
> >
> > I think that is probably a typo mistake, the voltage range and capacity is typical for 3000-3500 mAh li-ion cell.
> > It's a bit awkward to drill down to it, so here's a short cut. Go to this page:
> https://jonkersailplanes.co.za/res-system/
>
> Then scroll to the section with this:
>
>
> Battery specification
>
> Battery type EMECTRIC 96-4 400V
> Battery configuration 96S4P LiFePo
> Battery Voltage 270V-400V
> Capacity per battery 4.7kWh
> Battery Weight: 22kg (48.5 lbs)
> Maximum number of batteries 2
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
O

Yes, I saw the same.
But when you do the maths the values correspond to li-ion chemistry.

Eric Greenwell[_4_]

February 28th 21, 04:51 AM

wrote on 2/27/2021 3:30 PM:
> El sábado, 27 de febrero de 2021 a la(s) 20:07:36 UTC-3, Eric Greenwell escribió:
>> wrote on 2/27/2021 1:19 PM:
>>> Eric,
>>>
>>> I think that is probably a typo mistake, the voltage range and capacity is typical for 3000-3500 mAh li-ion cell.
>>> It's a bit awkward to drill down to it, so here's a short cut. Go to this page:
>> https://jonkersailplanes.co.za/res-system/
>>
>> Then scroll to the section with this:
>>
>>
>> Battery specification
>>
>> Battery type EMECTRIC 96-4 400V
>> Battery configuration 96S4P LiFePo
>> Battery Voltage 270V-400V
>> Capacity per battery 4.7kWh
>> Battery Weight: 22kg (48.5 lbs)
>> Maximum number of batteries 2
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> O
>
>
>
> Yes, I saw the same.
> But when you do the maths the values correspond to li-ion chemistry.
>
Ah, now I see what you mean, and since I can't find any mention of LifePo on the Emectric
website, I suspect you are right, and it is in error.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Scott Manley[_3_]

February 28th 21, 11:09 PM

One of the Alisport Silent 2 gliders being offered on Wings & Wheels is mine. It was the perfect glider for me. I literally loved everything about it. Easy to rig, easy to fly, all the glide performance I needed, simple operation of the power system. It is for sale because I decided to stop flying real aircraft, not because I am in any way disappointed with the aircraft. It is low time because I didn't fly it as much as I thought I would.

ProfJ

March 2nd 21, 09:10 PM

On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> Discus amongst yourselves...
Some comments:

- High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.

- Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.

Andrzej Kobus

March 3rd 21, 02:28 AM

On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
> On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
> > https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> > Discus amongst yourselves...
> Some comments:
>
> - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
>
> - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.

So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.

March 3rd 21, 03:25 AM

On Tuesday, March 2, 2021 at 6:28:27 PM UTC-8, Andrzej Kobus wrote:
> On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
> > On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
> > > https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> > > Discus amongst yourselves...
> > Some comments:
> >
> > - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
> >
> > - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.
> So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.

ICO glider engines have been developed over the last 70 years or so. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..

Tom

Eric Greenwell[_4_]

March 3rd 21, 04:27 AM

2G wrote on 3/2/2021 7:25 PM:
> On Tuesday, March 2, 2021 at 6:28:27 PM UTC-8, Andrzej Kobus wrote:
>> On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
>>> On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
>>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
>>>> Discus amongst yourselves...
>>> Some comments:
>>>
>>> - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
>>>
>>> - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.
>> So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.
>
> ICO glider engines have been developed over the last 70 years or so. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..

That immaturity means they have a lot of promise, compared to the ICE gliders. We know in 5
years the performance of the electrics will increase significantly; the fossil fueled ones -
not nearly so much. Even at the current immature stage, they are so desirable, all the major
manufacturers, and some of the second tier, offer at least two electric models in mast or FES
varieties.

I suggest that in maybe 5, but certainly in 10 years, the discussions will no longer be about
gas vs electric, but which electric to buy.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
lyhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1

March 4th 21, 02:11 AM

On Tuesday, March 2, 2021 at 8:27:55 PM UTC-8, Eric Greenwell wrote:
> 2G wrote on 3/2/2021 7:25 PM:
> > On Tuesday, March 2, 2021 at 6:28:27 PM UTC-8, Andrzej Kobus wrote:
> >> On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
> >>> On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
> >>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> >>>> Discus amongst yourselves...
> >>> Some comments:
> >>>
> >>> - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
> >>>
> >>> - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.
> >> So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.
> >
> > ICO glider engines have been developed over the last 70 years or so. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..
>
> That immaturity means they have a lot of promise, compared to the ICE gliders. We know in 5
> years the performance of the electrics will increase significantly; the fossil fueled ones -
> not nearly so much. Even at the current immature stage, they are so desirable, all the major
> manufacturers, and some of the second tier, offer at least two electric models in mast or FES
> varieties.
>
> I suggest that in maybe 5, but certainly in 10 years, the discussions will no longer be about
> gas vs electric, but which electric to buy.
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> lyhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1

Wishful thinking duly noted. The development, deployment and long-term flight experience of aircraft takes time. Ten years is a good estimate for a single model such as the Antares. Its first flight was in 2003, so development must have started about 20 years ago. I think that in 5 to 10 years we will be thinking "Boy, those electric gliders looked promising at the time, but if we knew then what we know now I would never have bought one." Successful product development just can't be rushed.

John Cochrane[_3_]

March 4th 21, 04:53 AM

For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.

John Cochrane BB

Eric Greenwell[_4_]

March 4th 21, 03:47 PM

John Cochrane wrote on 3/3/2021 8:53 PM:
> For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.
>
A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
your potential retrieve distance is shorter, instead of an imminent landing.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric Greenwell[_4_]

March 4th 21, 04:22 PM

2G wrote on 3/3/2021 6:11 PM:
> On Tuesday, March 2, 2021 at 8:27:55 PM UTC-8, Eric Greenwell wrote:
>> 2G wrote on 3/2/2021 7:25 PM:
>>> On Tuesday, March 2, 2021 at 6:28:27 PM UTC-8, Andrzej Kobus wrote:
>>>> On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
>>>>> On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
>>>>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
>>>>>> Discus amongst yourselves...
>>>>> Some comments:
>>>>>
>>>>> - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
>>>>>
>>>>> - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.
>>>> So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.
>>>
>>> ICO glider engines have been developed over the last 70 years or so. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..
>>
>> That immaturity means they have a lot of promise, compared to the ICE gliders. We know in 5
>> years the performance of the electrics will increase significantly; the fossil fueled ones -
>> not nearly so much. Even at the current immature stage, they are so desirable, all the major
>> manufacturers, and some of the second tier, offer at least two electric models in mast or FES
>> varieties.
>>
>> I suggest that in maybe 5, but certainly in 10 years, the discussions will no longer be about
>> gas vs electric, but which electric to buy.
>> --
yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> Wishful thinking duly noted. The development, deployment and long-term flight experience of aircraft takes time. Ten years is a good estimate for a single model such as the Antares. Its first flight was in 2003, so development must have started about 20 years ago. I think that in 5 to 10 years we will be thinking "Boy, those electric gliders looked promising at the time, but if we knew then what we know now I would never have bought one." Successful product development just can't be rushed.
>
It's not wishful thinking when there are four companies selling electric glider power systems:
Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers do not have to design
their own system, like Antares had to. That speeds development (even eliminates it in some
cases), reduces their cost, and increases reliability.

While the glider market is very small, the main component - batteries - is under intense
development by major corporations around the world. We will benefit from this investment,
without investing a dime in it.

As for glider pilots feeling sorry for their current electric choices in 5 or 10 years, well,
I'm going to suggest many glider pilots will be feeling sorry for their current gas engine
choices ;^)

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Hank Nixon

March 4th 21, 04:56 PM

On Wednesday, March 3, 2021 at 11:53:15 PM UTC-5, wrote:
> For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density.. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.
>
> John Cochrane BB
Hybrid, at best, would provide no benefit in weight and the complexity of both solutions added together.
The problem the manufacturer's have is that they know the users expect to launch at max weight and have acceptable safety margins at launch.
This requires powerful motors having high consumption. Oh- and we want long range for retrieves.
All this adds up to big batteries.
Now insert this into an airframe designed for high wing loading and IGC specified maximum mass.
You end up with a glider not suitable for eastern US, nor most of Europe.
Waiting for new batteries that will solve this problem is a fools errand.
Maybe manufacturers should consider 2 options on batteries. 1/2 the battery in the '33 would save somewhere around 65 lb by my estimate. On a 107 sq ft glider, that is a big deal.
I'm looking now at electric 29E possibility. With the system I have in the '24E(L) I would expect a launch and around 3000 feet of additional retrieve climb from a system that would add about 40 lb to the weight of the 29E. With 25kw available at launch I see as a dry self launch only ship.
FWIW
UH

Eric Greenwell[_4_]

March 4th 21, 06:24 PM

Hank Nixon wrote on 3/4/2021 8:56 AM:
> On Wednesday, March 3, 2021 at 11:53:15 PM UTC-5, wrote:
>> For the moment the big limitation seems to me to be weight. I looked hard at the AS33 electric. You get one launch to 2000' and then 9000' of climb to get home. For that, it's really hard to get off the ground at less than 10 lbs/ft2 empty, and 10.5 in 15 m mode. Gas has a wonderful energy density.. I'm surprised some sort of hybrid doesn't make sense, gas to recharge a smaller battery, then eliminate the drive elements with an electric motor. But I presume they worked the numbers on this.
>>
>> John Cochrane BB
> Hybrid, at best, would provide no benefit in weight and the complexity of both solutions added together.
> The problem the manufacturer's have is that they know the users expect to launch at max weight and have acceptable safety margins at launch.
> This requires powerful motors having high consumption. Oh- and we want long range for retrieves.
> All this adds up to big batteries.
> Now insert this into an airframe designed for high wing loading and IGC specified maximum mass.
> You end up with a glider not suitable for eastern US, nor most of Europe.
> Waiting for new batteries that will solve this problem is a fools errand.
> Maybe manufacturers should consider 2 options on batteries. 1/2 the battery in the '33 would save somewhere around 65 lb by my estimate. On a 107 sq ft glider, that is a big deal.
> I'm looking now at electric 29E possibility. With the system I have in the '24E(L) I would expect a launch and around 3000 feet of additional retrieve climb from a system that would add about 40 lb to the weight of the 29E. With 25kw available at launch I see as a dry self launch only ship.
> FWIW
> UH
>
The JS3 RES batteries are set up like an FES glider, even though it's a mast mounted motor
system: two batteries can be carried in the motor bay, but only one is required for operation.
They are about 50 lbs each. Being able to remove and charge them elsewhere should be a great
convenience.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Mark Mocho

March 4th 21, 07:55 PM

Energy density is the "elephant in the room" that determines a lot about electric vs. internal combustion. The Tesla S uses a 100 kWh battery that weighs 1,375 lbs. 100 kWh is approximately the same energy contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me. NOT!

And we aren't even bringing up the environmental impact of producing the battery and then disposing of it when its life is used up.

Nicholas Kennedy

March 4th 21, 09:02 PM

A Electrical engineer once said to me:
If you got a battery you got battery problems.
I own 3 vehicles and 3 motorcycle's, it seems like I'm always buying batteries.
When the tug rolls up to me and the line boy runs up with the rope I smile and say to my self
" this is cheap"
I generally release right into a big fat thermal.
Fly safe in 2021
Nick
T

john firth

March 4th 21, 09:02 PM

On Thursday, March 4, 2021 at 2:55:20 PM UTC-5, Mark Mocho wrote:
> Energy density is the "elephant in the room" that determines a lot about electric vs. internal combustion. The Tesla S uses a 100 kWh battery that weighs 1,375 lbs. 100 kWh is approximately the same energy contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me. NOT!
>
> And we aren't even bringing up the environmental impact of producing the battery and then disposing of it when its life is used up.

Has anyone in the SLS group been considering some FLYING?
the wave systems in the East have been awesome in the last few days (Mar02-04)
Not too cold at 10K (-10C) ; an eyeball dream suggested that Lk Placid to Bangor Me
and return (650KM) or much further south would have been possible.
Besides Lk Pl., there must be numerous airports with plowed runways and aprons.

enviously

John Firth (Ottawa)

PS cannot find how to start a new subject!

Martin Gregorie[_6_]

March 4th 21, 09:07 PM

On Thu, 04 Mar 2021 11:55:17 -0800, Mark Mocho wrote:

> Energy density is the "elephant in the room" that determines a lot about
> electric vs. internal combustion. The Tesla S uses a 100 kWh battery
> that weighs 1,375 lbs. 100 kWh is approximately the same energy
> contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity
> (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me.
> NOT!
>
> And we aren't even bringing up the environmental impact of producing the
> battery and then disposing of it when its life is used up.

Here are some free-wheeling thoughts inspired by what I've read about the
Aptera hybrid road vehicles: the prototype used an all-electric drive
chain connected to a battery with a 40 mile range when fully charged. It
also carried a small ICE generator pack - on ling trips the rig was said
to average 120 mpg.

So, how would a similar set-up work for us?

Say, use a pylon-mounted electric motor coupled to a battery capable of
take-off olus a 2000 ft climb (i.e. a somewhat higher than normal winch
launch) and carry a small ICE generator pack to be run during and after
launch to recharge the battery.

A modern 20cc 2-stroke can knock out 2.5 hp at 9000rpm (around 1.8 kWh,
so with a 40% efficient generator you can recharge the battery at a 0.7
kWh rate from a unit with a guestimated weight of 1.5 Kg (750 g motor
plus the same weight for the generator) plus fuel at around 9,7 kWh/litre
(thats 12 kWh/kg) so something like 1.2 kWh/liter of fuel can be put back
into the battery after launch (assuming motor efficiency 25% and
generator efficiency 40%). Now, scale the system up a bit and use a 200cc
generator set and you've got an equipment weight of 15 kg plus fuel and a
recharge rate of around 12 kWh. Time to recharge a 20 Kwh launch battery
is around 1.7 hours, so a fair time to be listening to the (muffled)
engine behind you, but a much lighter system than a pure electric system
(launch battery + 15kg generator set) would be.

What did I miss?

--
Martin | martin at
Gregorie | gregorie dot org

Eric Greenwell[_4_]

March 4th 21, 09:11 PM

Mark Mocho wrote on 3/4/2021 11:55 AM:
> Energy density is the "elephant in the room" that determines a lot about electric vs. internal combustion. The Tesla S uses a 100 kWh battery that weighs 1,375 lbs. 100 kWh is approximately the same energy contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me. NOT!
>
> And we aren't even bringing up the environmental impact of producing the battery and then disposing of it when its life is used up.
>

There seems to be an anomaly with your numbers: The 100 kWh battery delivers about 400 miles of
range. How is it possible to go that far on the equivalent of 2.1 gallons of Av Gas?

And yet, wouldn't you love to have access to a Tesla S? I know I would! I was an engineer
during my working years, and even I don't buy energy density when I choose a car (or glider),
and neither do pilots looking for a self-launching glider. And obviously, they are finding what
they like, despite the energy density disparity.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Dan Marotta

March 4th 21, 09:27 PM

9,000 RPM makes quite a racket, no matter the muffler. Have a good
noise canceling headset...

Dan
5J

On 3/4/21 2:07 PM, Martin Gregorie wrote:
> On Thu, 04 Mar 2021 11:55:17 -0800, Mark Mocho wrote:
>
>> Energy density is the "elephant in the room" that determines a lot about
>> electric vs. internal combustion. The Tesla S uses a 100 kWh battery
>> that weighs 1,375 lbs. 100 kWh is approximately the same energy
>> contained in 2.1 gallons of AvGas. So, you have a 2 gallon capacity
>> (about 13 lbs.) in a 1,375 lb. container. Makes perfect sense to me.
>> NOT!
>>
>> And we aren't even bringing up the environmental impact of producing the
>> battery and then disposing of it when its life is used up.
>
> Here are some free-wheeling thoughts inspired by what I've read about the
> Aptera hybrid road vehicles: the prototype used an all-electric drive
> chain connected to a battery with a 40 mile range when fully charged. It
> also carried a small ICE generator pack - on ling trips the rig was said
> to average 120 mpg.
>
> So, how would a similar set-up work for us?
>
> Say, use a pylon-mounted electric motor coupled to a battery capable of
> take-off olus a 2000 ft climb (i.e. a somewhat higher than normal winch
> launch) and carry a small ICE generator pack to be run during and after
> launch to recharge the battery.
>
> A modern 20cc 2-stroke can knock out 2.5 hp at 9000rpm (around 1.8 kWh,
> so with a 40% efficient generator you can recharge the battery at a 0.7
> kWh rate from a unit with a guestimated weight of 1.5 Kg (750 g motor
> plus the same weight for the generator) plus fuel at around 9,7 kWh/litre
> (thats 12 kWh/kg) so something like 1.2 kWh/liter of fuel can be put back
> into the battery after launch (assuming motor efficiency 25% and
> generator efficiency 40%). Now, scale the system up a bit and use a 200cc
> generator set and you've got an equipment weight of 15 kg plus fuel and a
> recharge rate of around 12 kWh. Time to recharge a 20 Kwh launch battery
> is around 1.7 hours, so a fair time to be listening to the (muffled)
> engine behind you, but a much lighter system than a pure electric system
> (launch battery + 15kg generator set) would be.
>
> What did I miss?
>
>

Kenn Sebesta

March 4th 21, 09:55 PM

> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> your potential retrieve distance is shorter, instead of an imminent landing.

I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.

I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.

Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

Martin Gregorie[_6_]

March 4th 21, 10:00 PM

On Thu, 04 Mar 2021 14:27:53 -0700, Dan Marotta wrote:

> 9,000 RPM makes quite a racket, no matter the muffler. Have a good
> noise canceling headset...
>
Yeah, I know - the engine I took weight and power numbers was a 20cc RC
aircraft engine, while I was iriginally thinking of thre 20cc petrol
engines you used to see on small chainsaws and big drills.

But, add a bit of weight and bulk for water cooling and put it in a sound-
absorbing box with the motor/generator combo sat on rubber mounts and I
think you cound reduce the sound level quite a lot.

But, the main poing of my piece was to show just how light and relatively
fuel efficient such a small generator set would be compared with an
battery of equivalent capacity.

A litre of gas or diesel fuel weighs 800g and has an energy capacity of
9.7 kWh.

Totally OTT: As an ex-free flight model flyer, I think the finest engine
sound I've ever heard was a 1cc Cyclon-06 glow motor with an open exhaust
spinning a 7" x 4" prop at 30,500 rpm on 25% nitro fuel mix.

--
Martin | martin at
Gregorie | gregorie dot org

Moshe Braner

March 4th 21, 10:15 PM

On 3/4/2021 5:00 PM, Martin Gregorie wrote:
> On Thu, 04 Mar 2021 14:27:53 -0700, Dan Marotta wrote:
>
>> 9,000 RPM makes quite a racket, no matter the muffler. Have a good
>> noise canceling headset...
>>
> Yeah, I know - the engine I took weight and power numbers was a 20cc RC
> aircraft engine, while I was iriginally thinking of thre 20cc petrol
> engines you used to see on small chainsaws and big drills.
>
> But, add a bit of weight and bulk for water cooling and put it in a sound-
> absorbing box with the motor/generator combo sat on rubber mounts and I
> think you cound reduce the sound level quite a lot.
>
> But, the main poing of my piece was to show just how light and relatively
> fuel efficient such a small generator set would be compared with an
> battery of equivalent capacity.
>
> A litre of gas or diesel fuel weighs 800g and has an energy capacity of
> 9.7 kWh.
>
> Totally OTT: As an ex-free flight model flyer, I think the finest engine
> sound I've ever heard was a 1cc Cyclon-06 glow motor with an open exhaust
> spinning a 7" x 4" prop at 30,500 rpm on 25% nitro fuel mix.
>
>

I'd prefer a quiet engine, like the ones on small Honda generators.
Presumably 4-stroke, so a bit heavier, but very efficient (for a small ICE).

I'll leave it to the IGC folks to tear their hair out on how to deal
with the engine noise no longer being an indicator of (simultaneous)
propulsion.

Perhaps for a "sustainer" model you could run the engine only when you
decide you need propulsion, and have an engine large enough to supply as
much power to the batteries as the electric motor is using, or a bit more.

Mark Mocho

March 4th 21, 11:30 PM

"There seems to be an anomaly with your numbers: The 100 kWh battery delivers about 400 miles of
range. How is it possible to go that far on the equivalent of 2.1 gallons of Av Gas?"

Eric- the main reason that the numbers seem skewed is the relative efficiency difference between modern brushless electric motors (often over 90%) and typical Internal combustion engines, which barely reach 30% efficiency.

For a reasonable overview of the gas vs. electric debate, I highly recommend an article in the January 2021 issue of "AOPA PIlot" magazine entitled "hp versus kW" by Peter Rez, "an Arizona State University physics professor from Scottsdale who flies a Mooney."

Matthew Scutter

March 5th 21, 02:15 AM

On Friday, March 5, 2021 at 9:30:31 AM UTC+10, Mark Mocho wrote:
> "There seems to be an anomaly with your numbers: The 100 kWh battery delivers about 400 miles of
> range. How is it possible to go that far on the equivalent of 2.1 gallons of Av Gas?"
> Eric- the main reason that the numbers seem skewed is the relative efficiency difference between modern brushless electric motors (often over 90%) and typical Internal combustion engines, which barely reach 30% efficiency.
>
> For a reasonable overview of the gas vs. electric debate, I highly recommend an article in the January 2021 issue of "AOPA PIlot" magazine entitled "hp versus kW" by Peter Rez, "an Arizona State University physics professor from Scottsdale who flies a Mooney."

I think what he was trying to get at, is that comparing on the basis of energy density isn't very meaningful. We should be comparing distance-retrievable/kg and height-climbable/kg across different ICE and electric solutions.

Hank Nixon

March 5th 21, 01:00 PM

On Thursday, March 4, 2021 at 4:55:30 PM UTC-5, Kenn Sebesta wrote:
> > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > your potential retrieve distance is shorter, instead of an imminent landing.
> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
>
> I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>
> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

What is contact info for the list mentioned?
Thx
UH

Kenn Sebesta

March 5th 21, 03:50 PM

On Friday, March 5, 2021 at 8:00:05 AM UTC-5, Hank Nixon wrote:
> On Thursday, March 4, 2021 at 4:55:30 PM UTC-5, Kenn Sebesta wrote:
> > ... There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me)...
> What is contact info for the list mentioned?
> Thx
> UH

While Google Groups no longer displays email addresses, they can be pulled from RSS readers. I sent you an invite.

(Sometime in the near future I'll set up a better way to join the group.)

March 5th 21, 04:29 PM

On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
> 2G wrote on 3/3/2021 6:11 PM:
> > On Tuesday, March 2, 2021 at 8:27:55 PM UTC-8, Eric Greenwell wrote:
> >> 2G wrote on 3/2/2021 7:25 PM:
> >>> On Tuesday, March 2, 2021 at 6:28:27 PM UTC-8, Andrzej Kobus wrote:
> >>>> On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
> >>>>> On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
> >>>>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> >>>>>> Discus amongst yourselves...
> >>>>> Some comments:
> >>>>>
> >>>>> - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
> >>>>>
> >>>>> - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.
> >>>> So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.
> >>>
> >>> ICO glider engines have been developed over the last 70 years or so. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..
> >>
> >> That immaturity means they have a lot of promise, compared to the ICE gliders. We know in 5
> >> years the performance of the electrics will increase significantly; the fossil fueled ones -
> >> not nearly so much. Even at the current immature stage, they are so desirable, all the major
> >> manufacturers, and some of the second tier, offer at least two electric models in mast or FES
> >> varieties.
> >>
> >> I suggest that in maybe 5, but certainly in 10 years, the discussions will no longer be about
> >> gas vs electric, but which electric to buy.
> >> --
> yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > Wishful thinking duly noted. The development, deployment and long-term flight experience of aircraft takes time. Ten years is a good estimate for a single model such as the Antares. Its first flight was in 2003, so development must have started about 20 years ago. I think that in 5 to 10 years we will be thinking "Boy, those electric gliders looked promising at the time, but if we knew then what we know now I would never have bought one." Successful product development just can't be rushed.
> >
> It's not wishful thinking when there are four companies selling electric glider power systems:
> Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers do not have to design
> their own system, like Antares had to. That speeds development (even eliminates it in some
> cases), reduces their cost, and increases reliability.
>
> While the glider market is very small, the main component - batteries - is under intense
> development by major corporations around the world. We will benefit from this investment,
> without investing a dime in it.
>
> As for glider pilots feeling sorry for their current electric choices in 5 or 10 years, well,
> I'm going to suggest many glider pilots will be feeling sorry for their current gas engine
> choices ;^)
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Predicting the future is ALWAYS wishful thinking. If you could actually do it reliably you would be a billionaire. Having four companies doing it doesn't mean the development is 4 times as fast, you just get 4 possible failures instead of one.

There are already some pieces of "common wisdom" that have been debunked. One is that electric is inherently more reliable than ICE. The fire incidents are of greatest concern. Dave's issues with his Antares are also troubling - systems that are dependent on complex software can have failure modes that are only found by extensive testing. I know of another Antares owner who had to fly a technician over from Germany to fix the problems with his glider. And the small numbers of electric gliders means that buyers will ultimately do most of the testing themselves. Long term support of these complex systems is yet another question.

BobW

March 5th 21, 04:57 PM

> Predicting the future is ALWAYS wishful thinking. If you could actually do
> it reliably you would be a billionaire. Having four companies doing it
> doesn't mean the development is 4 times as fast, you just get 4 possible
> failures instead of one.

Yogi Berra - many laughed at him - was right. (Look up his body of work
involving malapropic wisdoms...you'll know when you've found the appropriate
one for this particular bit of thread drift!) Perhaps tellingly, he never
became a billionaire.

Who knows - he mighta been a decent soaring pilot!

Hank Nixon

March 5th 21, 05:05 PM

On Friday, March 5, 2021 at 11:29:30 AM UTC-5, 2G wrote:
> On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
> > 2G wrote on 3/3/2021 6:11 PM:
> > > On Tuesday, March 2, 2021 at 8:27:55 PM UTC-8, Eric Greenwell wrote:
> > >> 2G wrote on 3/2/2021 7:25 PM:
> > >>> On Tuesday, March 2, 2021 at 6:28:27 PM UTC-8, Andrzej Kobus wrote:
> > >>>> On Tuesday, March 2, 2021 at 4:10:48 PM UTC-5, ProfJ wrote:
> > >>>>> On Wednesday, 24 February 2021 at 14:42:01 UTC-7, wrote:
> > >>>>>> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> > >>>>>> Discus amongst yourselves...
> > >>>>> Some comments:
> > >>>>>
> > >>>>> - High current draw for VTO launches (Lilium) - IIRC they are planning to use supercapacitors to provide the current boost so that the batteries don't have to. A supercapacitor/LiPo combination makes a lot of sense for that problem.
> > >>>>>
> > >>>>> - Electric vs. gas: a very experienced motorglider ferry pilot, who I am sure does not want to be named, once told me when discussing Stemmes: "I've had every known Stemme issue except the in-flight fire, I'm not looking forward to that one..." I side with Eric here - we have normalized all the hassle that goes with gas self-launchers. When we get mature technology electric self-launchers, they'll dominate. Current complaints about electric sound exactly like the complaints about electric cars, before Tesla got it right.
> > >>>> So how big is the electric glider market vs. electric car market? Things get done with proper research and funding. I don't see that happen for the glider market. I suggest you review David's presentation. He discussed this point.
> > >>>
> > >>> ICO glider engines have been developed over the last 70 years or so.. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..
> > >>
> > >> That immaturity means they have a lot of promise, compared to the ICE gliders. We know in 5
> > >> years the performance of the electrics will increase significantly; the fossil fueled ones -
> > >> not nearly so much. Even at the current immature stage, they are so desirable, all the major
> > >> manufacturers, and some of the second tier, offer at least two electric models in mast or FES
> > >> varieties.
> > >>
> > >> I suggest that in maybe 5, but certainly in 10 years, the discussions will no longer be about
> > >> gas vs electric, but which electric to buy.
> > >> --
> > yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > >
> > > Wishful thinking duly noted. The development, deployment and long-term flight experience of aircraft takes time. Ten years is a good estimate for a single model such as the Antares. Its first flight was in 2003, so development must have started about 20 years ago. I think that in 5 to 10 years we will be thinking "Boy, those electric gliders looked promising at the time, but if we knew then what we know now I would never have bought one." Successful product development just can't be rushed.
> > >
> > It's not wishful thinking when there are four companies selling electric glider power systems:
> > Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers do not have to design
> > their own system, like Antares had to. That speeds development (even eliminates it in some
> > cases), reduces their cost, and increases reliability.
> >
> > While the glider market is very small, the main component - batteries - is under intense
> > development by major corporations around the world. We will benefit from this investment,
> > without investing a dime in it.
> >
> > As for glider pilots feeling sorry for their current electric choices in 5 or 10 years, well,
> > I'm going to suggest many glider pilots will be feeling sorry for their current gas engine
> > choices ;^)
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> Predicting the future is ALWAYS wishful thinking. If you could actually do it reliably you would be a billionaire. Having four companies doing it doesn't mean the development is 4 times as fast, you just get 4 possible failures instead of one.
>
> There are already some pieces of "common wisdom" that have been debunked. One is that electric is inherently more reliable than ICE. The fire incidents are of greatest concern. Dave's issues with his Antares are also troubling - systems that are dependent on complex software can have failure modes that are only found by extensive testing. I know of another Antares owner who had to fly a technician over from Germany to fix the problems with his glider. And the small numbers of electric gliders means that buyers will ultimately do most of the testing themselves. Long term support of these complex systems is yet another question.

You can't buy experience, but you do pay for it!
UH

Eric Greenwell[_4_]

March 5th 21, 05:16 PM

2G wrote on 3/5/2021 8:29 AM:
> On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
>> 2G wrote on 3/3/2021 6:11 PM:
....
>>>>>
>>>>> ICO glider engines have been developed over the last 70 years or so. And, then, many of them have come from the 2-cycle engine applications such as snowmobiles and ultralights. The electric glider market is much more immature..
>>>>
>>>> That immaturity means they have a lot of promise, compared to the ICE gliders. We know in 5
>>>> years the performance of the electrics will increase significantly; the fossil fueled ones -
>>>> not nearly so much. Even at the current immature stage, they are so desirable, all the major
>>>> manufacturers, and some of the second tier, offer at least two electric models in mast or FES
>>>> varieties.
>>>>
>>>> I suggest that in maybe 5, but certainly in 10 years, the discussions will no longer be about
>>>> gas vs electric, but which electric to buy.
>>>> --
>> yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>
>>> Wishful thinking duly noted. The development, deployment and long-term flight experience of aircraft takes time. Ten years is a good estimate for a single model such as the Antares. Its first flight was in 2003, so development must have started about 20 years ago. I think that in 5 to 10 years we will be thinking "Boy, those electric gliders looked promising at the time, but if we knew then what we know now I would never have bought one." Successful product development just can't be rushed.
>>>
>> It's not wishful thinking when there are four companies selling electric glider power systems:
>> Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers do not have to design
>> their own system, like Antares had to. That speeds development (even eliminates it in some
>> cases), reduces their cost, and increases reliability.
>>
>> While the glider market is very small, the main component - batteries - is under intense
>> development by major corporations around the world. We will benefit from this investment,
>> without investing a dime in it.
>>
>> As for glider pilots feeling sorry for their current electric choices in 5 or 10 years, well,
>> I'm going to suggest many glider pilots will be feeling sorry for their current gas engine
>> choices ;^)
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> Predicting the future is ALWAYS wishful thinking. If you could actually do it reliably you would be a billionaire. Having four companies doing it doesn't mean the development is 4 times as fast, you just get 4 possible failures instead of one.
>
> There are already some pieces of "common wisdom" that have been debunked. One is that electric is inherently more reliable than ICE. The fire incidents are of greatest concern. Dave's issues with his Antares are also troubling - systems that are dependent on complex software can have failure modes that are only found by extensive testing. I know of another Antares owner who had to fly a technician over from Germany to fix the problems with his glider. And the small numbers of electric gliders means that buyers will ultimately do most of the testing themselves. Long term support of these complex systems is yet another question.
>
I apologize to all readers for the repetition: The Antares was a pioneering effort, and you can
recognize a pioneer by the arrows in his back. Schleicher, Schempp-Hirth, Jonkers, and others,
are not following the Antares path. They are not pioneers, but cautious "settlers" that follow
after the pioneers have showed them where to go.

There are far more FES gliders flying than Antares, and very successfully. The problems that
occur are solved by LZ Design, not the glider manufacturers. The eglider segment of gliding has
reached the "specialization" stage, and to talk about Dave's Antares problems is to miss the
future because you are focusing on a pioneering glider designed and built almost two decades ago.

The future, which is now, includes mast-mounted options from several manufacturers. The "old"
manufacturers got old by not being too bold: they are cautious, risk-adverse companies that see
a burgeoning opportunity they have to join. There will not be fleets of egliders from these
companies 5 or 10 years from now, sitting on the ground, unused.

I've seen this happen before, with the ASH26E (my current glider), which was quite bold in
1994: the first retracting self-launching sailplane from Schleicher, using a Wankel engine, and
- horrors - only a 18m wingspan when there was no 18M class! There were problems, especially in
the first 5 years, but they made it work, didn't they? You've owned one! And they (and the
other manufacturers) will make the egliders work, and work well.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[email protected]

March 5th 21, 05:59 PM

Kenn,

Can you add me to that group too?
emirsherbi at g m ail

Regards

Mark Mocho

March 5th 21, 07:29 PM

"Having four companies doing it doesn't mean the development is 4 times as fast, you just get 4 possible failures instead of one."

â€œCrash programs fail because they are based on the theory that, with nine women pregnant, you can get a baby a month.â€

(Wernher von Braun)

Bob Kuykendall

March 6th 21, 02:10 AM

On Friday, March 5, 2021 at 9:16:58 AM UTC-8, Eric Greenwell wrote:

> I apologize to all readers for the repetition: The Antares was a pioneering effort, and you can
> recognize a pioneer by the arrows in [their] back.

In the Silicon Valley, we say:

"The early bird gets the worm. The second mouse gets the cheese."

In my practical experience, the second mouse also often eats the first mouse.

--Bob K.

kinsell

March 6th 21, 04:28 AM

On 3/5/21 10:16 AM, Eric Greenwell wrote:
> 2G wrote on 3/5/2021 8:29 AM:
>> On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
>>> 2G wrote on 3/3/2021 6:11 PM:
> ...
>>>>>>
>>>>>> ICO glider engines have been developed over the last 70 years or
>>>>>> so. And, then, many of them have come from the 2-cycle engine
>>>>>> applications such as snowmobiles and ultralights. The electric
>>>>>> glider market is much more immature..
>>>>>
>>>>> That immaturity means they have a lot of promise, compared to the
>>>>> ICE gliders. We know in 5
>>>>> years the performance of the electrics will increase significantly;
>>>>> the fossil fueled ones -
>>>>> not nearly so much. Even at the current immature stage, they are so
>>>>> desirable, all the major
>>>>> manufacturers, and some of the second tier, offer at least two
>>>>> electric models in mast or FES
>>>>> varieties.
>>>>>
>>>>> I suggest that in maybe 5, but certainly in 10 years, the
>>>>> discussions will no longer be about
>>>>> gas vs electric, but which electric to buy.
>>>>> --
>>> yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>
>>>>
>>>> Wishful thinking duly noted. The development, deployment and
>>>> long-term flight experience of aircraft takes time. Ten years is a
>>>> good estimate for a single model such as the Antares. Its first
>>>> flight was in 2003, so development must have started about 20 years
>>>> ago. I think that in 5 to 10 years we will be thinking "Boy, those
>>>> electric gliders looked promising at the time, but if we knew then
>>>> what we know now I would never have bought one." Successful product
>>>> development just can't be rushed.
>>>>
>>> It's not wishful thinking when there are four companies selling
>>> electric glider power systems:
>>> Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers
>>> do not have to design
>>> their own system, like Antares had to. That speeds development (even
>>> eliminates it in some
>>> cases), reduces their cost, and increases reliability.
>>>
>>> While the glider market is very small, the main component - batteries
>>> - is under intense
>>> development by major corporations around the world. We will benefit
>>> from this investment,
>>> without investing a dime in it.
>>>
>>> As for glider pilots feeling sorry for their current electric choices
>>> in 5 or 10 years, well,
>>> I'm going to suggest many glider pilots will be feeling sorry for
>>> their current gas engine
>>> choices ;^)
>>> --
>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>>> email me)
>>> - "A Guide to Self-Launching Sailplane Operation"
>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>
>>
>> Predicting the future is ALWAYS wishful thinking. If you could
>> actually do it reliably you would be a billionaire. Having four
>> companies doing it doesn't mean the development is 4 times as fast,
>> you just get 4 possible failures instead of one.
>>
>> There are already some pieces of "common wisdom" that have been
>> debunked. One is that electric is inherently more reliable than ICE.
>> The fire incidents are of greatest concern. Dave's issues with his
>> Antares are also troubling - systems that are dependent on complex
>> software can have failure modes that are only found by extensive
>> testing. I know of another Antares owner who had to fly a technician
>> over from Germany to fix the problems with his glider. And the small
>> numbers of electric gliders means that buyers will ultimately do most
>> of the testing themselves. Long term support of these complex systems
>> is yet another question.
>>
> I apologize to all readers for the repetition: The Antares was a
> pioneering effort, and you can recognize a pioneer by the arrows in his
> back. Schleicher, Schempp-Hirth, Jonkers, and others, are not following
> the Antares path. They are not pioneers, but cautious "settlers" that
> follow after the pioneers have showed them where to go.
>
> There are far more FES gliders flying than Antares, and very
> successfully. The problems that occur are solved by LZ Design, not the
> glider manufacturers. The eglider segment of gliding has reached the
> "specialization" stage, and to talk about Dave's Antares problems is to
> miss the future because you are focusing on a pioneering glider designed
> and built almost two decades ago.
>
> The future, which is now, includes mast-mounted options from several
> manufacturers. The "old" manufacturers got old by not being too bold:
> they are cautious, risk-adverse companies that see a burgeoning
> opportunity they have to join. There will not be fleets of egliders from
> these companies 5 or 10 years from now, sitting on the ground, unused.
>
> I've seen this happen before, with the ASH26E (my current glider), which
> was quite bold in 1994: the first retracting self-launching sailplane
> from Schleicher, using a Wankel engine, and - horrors - only a 18m
> wingspan when there was no 18M class! There were problems, especially in
> the first 5 years, but they made it work, didn't they? You've owned one!
> And they (and the other manufacturers) will make the egliders work, and
> work well.
>

Don't think anybody is going to predict the future five years out.
Maybe there will be some big breakthrough in batteries, maybe not.

FES gliders have been out almost 10 years now, what is clear is their
history. Underpowered back then, underpowered still today. Makes you
wonder where these huge improvements in capacity are hiding. Some are
being sold as self launchers, even when flown as sustainers they're
still landing out.

CNN proclaimed back in 2017 that lilium was just around the corner.
Four years later, they have one burned up prototype, another one that
hasn't flown, and now they're saying they didn't really intend to
certify that design anyway. Huge shock for Herb, but not everything you
hear on CNN is true.

The electric beaver folks have been awful quiet after demonstrating a
single three minute flight. They claimed they were going to be in
commercial operation in 2022. Uh-huh. Not sure why you'd certify a
passenger plane that has no room left for passengers. Made for lots of
phony press releases though.

The Alice in Wonderland folks burned up their prototype last year, now
they're back with a radically different airframe design, and claiming
first flight will be in 2021. You betcha. Maybe they burned that proto
because the knew it never was going to fly? They did have a fire engine
standing by.

The electric Caravan folks fried their inverter during their big demo
flight, put the turbine back on it and are trying to sell it.

Maybe electrics will make huge progress, wouldn't that be great? But
I'm not going to lose any sleep over it. Nor am I excited about the
current offerings.

jfitch

March 6th 21, 04:56 AM

Comparisons of commercial air transport with self launched gliders are specious, very different energy use profile. Same with cars vs. self launched gliders. In either case though, the energy density difference between 100LL and state-of-the-art batteries is hard to ignore - at least 30:1 at this moment, and still 10:1 even considering relative efficiencies. I've no doubt electrics will eventually take over, the question is only if you buy one now, how early are you in the development cycle? Once the cycle is mature, there should be a market for a drop in electric replacement for aging ICE powerplants on popular gliders.

On Friday, March 5, 2021 at 8:28:29 PM UTC-8, kinsell wrote:
> On 3/5/21 10:16 AM, Eric Greenwell wrote:
> > 2G wrote on 3/5/2021 8:29 AM:
> >> On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
> >>> 2G wrote on 3/3/2021 6:11 PM:
> > ...
> >>>>>>
> >>>>>> ICO glider engines have been developed over the last 70 years or
> >>>>>> so. And, then, many of them have come from the 2-cycle engine
> >>>>>> applications such as snowmobiles and ultralights. The electric
> >>>>>> glider market is much more immature..
> >>>>>
> >>>>> That immaturity means they have a lot of promise, compared to the
> >>>>> ICE gliders. We know in 5
> >>>>> years the performance of the electrics will increase significantly;
> >>>>> the fossil fueled ones -
> >>>>> not nearly so much. Even at the current immature stage, they are so
> >>>>> desirable, all the major
> >>>>> manufacturers, and some of the second tier, offer at least two
> >>>>> electric models in mast or FES
> >>>>> varieties.
> >>>>>
> >>>>> I suggest that in maybe 5, but certainly in 10 years, the
> >>>>> discussions will no longer be about
> >>>>> gas vs electric, but which electric to buy.
> >>>>> --
> >>> yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >>>
> >>>>
> >>>> Wishful thinking duly noted. The development, deployment and
> >>>> long-term flight experience of aircraft takes time. Ten years is a
> >>>> good estimate for a single model such as the Antares. Its first
> >>>> flight was in 2003, so development must have started about 20 years
> >>>> ago. I think that in 5 to 10 years we will be thinking "Boy, those
> >>>> electric gliders looked promising at the time, but if we knew then
> >>>> what we know now I would never have bought one." Successful product
> >>>> development just can't be rushed.
> >>>>
> >>> It's not wishful thinking when there are four companies selling
> >>> electric glider power systems:
> >>> Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers
> >>> do not have to design
> >>> their own system, like Antares had to. That speeds development (even
> >>> eliminates it in some
> >>> cases), reduces their cost, and increases reliability.
> >>>
> >>> While the glider market is very small, the main component - batteries
> >>> - is under intense
> >>> development by major corporations around the world. We will benefit
> >>> from this investment,
> >>> without investing a dime in it.
> >>>
> >>> As for glider pilots feeling sorry for their current electric choices
> >>> in 5 or 10 years, well,
> >>> I'm going to suggest many glider pilots will be feeling sorry for
> >>> their current gas engine
> >>> choices ;^)
> >>> --
> >>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
> >>> email me)
> >>> - "A Guide to Self-Launching Sailplane Operation"
> >>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >>>
> >>
> >> Predicting the future is ALWAYS wishful thinking. If you could
> >> actually do it reliably you would be a billionaire. Having four
> >> companies doing it doesn't mean the development is 4 times as fast,
> >> you just get 4 possible failures instead of one.
> >>
> >> There are already some pieces of "common wisdom" that have been
> >> debunked. One is that electric is inherently more reliable than ICE.
> >> The fire incidents are of greatest concern. Dave's issues with his
> >> Antares are also troubling - systems that are dependent on complex
> >> software can have failure modes that are only found by extensive
> >> testing. I know of another Antares owner who had to fly a technician
> >> over from Germany to fix the problems with his glider. And the small
> >> numbers of electric gliders means that buyers will ultimately do most
> >> of the testing themselves. Long term support of these complex systems
> >> is yet another question.
> >>
> > I apologize to all readers for the repetition: The Antares was a
> > pioneering effort, and you can recognize a pioneer by the arrows in his
> > back. Schleicher, Schempp-Hirth, Jonkers, and others, are not following
> > the Antares path. They are not pioneers, but cautious "settlers" that
> > follow after the pioneers have showed them where to go.
> >
> > There are far more FES gliders flying than Antares, and very
> > successfully. The problems that occur are solved by LZ Design, not the
> > glider manufacturers. The eglider segment of gliding has reached the
> > "specialization" stage, and to talk about Dave's Antares problems is to
> > miss the future because you are focusing on a pioneering glider designed
> > and built almost two decades ago.
> >
> > The future, which is now, includes mast-mounted options from several
> > manufacturers. The "old" manufacturers got old by not being too bold:
> > they are cautious, risk-adverse companies that see a burgeoning
> > opportunity they have to join. There will not be fleets of egliders from
> > these companies 5 or 10 years from now, sitting on the ground, unused.
> >
> > I've seen this happen before, with the ASH26E (my current glider), which
> > was quite bold in 1994: the first retracting self-launching sailplane
> > from Schleicher, using a Wankel engine, and - horrors - only a 18m
> > wingspan when there was no 18M class! There were problems, especially in
> > the first 5 years, but they made it work, didn't they? You've owned one!
> > And they (and the other manufacturers) will make the egliders work, and
> > work well.
> >
> Don't think anybody is going to predict the future five years out.
> Maybe there will be some big breakthrough in batteries, maybe not.
>
> FES gliders have been out almost 10 years now, what is clear is their
> history. Underpowered back then, underpowered still today. Makes you
> wonder where these huge improvements in capacity are hiding. Some are
> being sold as self launchers, even when flown as sustainers they're
> still landing out.
>
> CNN proclaimed back in 2017 that lilium was just around the corner.
> Four years later, they have one burned up prototype, another one that
> hasn't flown, and now they're saying they didn't really intend to
> certify that design anyway. Huge shock for Herb, but not everything you
> hear on CNN is true.
>
> The electric beaver folks have been awful quiet after demonstrating a
> single three minute flight. They claimed they were going to be in
> commercial operation in 2022. Uh-huh. Not sure why you'd certify a
> passenger plane that has no room left for passengers. Made for lots of
> phony press releases though.
>
> The Alice in Wonderland folks burned up their prototype last year, now
> they're back with a radically different airframe design, and claiming
> first flight will be in 2021. You betcha. Maybe they burned that proto
> because the knew it never was going to fly? They did have a fire engine
> standing by.
>
> The electric Caravan folks fried their inverter during their big demo
> flight, put the turbine back on it and are trying to sell it.
>
> Maybe electrics will make huge progress, wouldn't that be great? But
> I'm not going to lose any sleep over it. Nor am I excited about the
> current offerings.

Eric Greenwell[_4_]

March 6th 21, 04:58 AM

kinsell wrote on 3/5/2021 8:28 PM:
> FES gliders have been out almost 10 years now, what is clear is their history.* Underpowered
> back then, underpowered still today.* Makes you wonder where these huge improvements in
> capacity are hiding.* Some are being sold as self launchers, even when flown as sustainers
> they're still landing out.

The airplane examples you mention don't apply to us, because their goals are very different,
and are much more difficult to achieve. Your judgement that FES gliders are under powered is
just an opinion, one that is obviously not shared by the major manufacturers, who have
increased their FES offerings substantially in the last 10 years, nor is it shared by the
increasing number of glider pilots that are buying them. I'm sure every owner of an FES glider
wishes it had more power; in fact, I've had the same wish for my ASH 26E! But overall, the
26E's attributes are attractive enough that I've flown it for 26 years, and the FES attributes
are attractive enough that many pilots buy them.

It's important to remember many pilots buying an FES glider are coming from an unpowered
glider, so they think the ability to self-launch is an amazing upgrade, and to have a modest
retrieve capability is an outstanding addition!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Herbert kilian

March 6th 21, 03:13 PM

On Friday, March 5, 2021 at 10:28:29 PM UTC-6, kinsell wrote:
> On 3/5/21 10:16 AM, Eric Greenwell wrote:
> > 2G wrote on 3/5/2021 8:29 AM:
> >> On Thursday, March 4, 2021 at 8:22:34 AM UTC-8, Eric Greenwell wrote:
> >>> 2G wrote on 3/3/2021 6:11 PM:
> > ...
> >>>>>>
> >>>>>> ICO glider engines have been developed over the last 70 years or
> >>>>>> so. And, then, many of them have come from the 2-cycle engine
> >>>>>> applications such as snowmobiles and ultralights. The electric
> >>>>>> glider market is much more immature..
> >>>>>
> >>>>> That immaturity means they have a lot of promise, compared to the
> >>>>> ICE gliders. We know in 5
> >>>>> years the performance of the electrics will increase significantly;
> >>>>> the fossil fueled ones -
> >>>>> not nearly so much. Even at the current immature stage, they are so
> >>>>> desirable, all the major
> >>>>> manufacturers, and some of the second tier, offer at least two
> >>>>> electric models in mast or FES
> >>>>> varieties.
> >>>>>
> >>>>> I suggest that in maybe 5, but certainly in 10 years, the
> >>>>> discussions will no longer be about
> >>>>> gas vs electric, but which electric to buy.
> >>>>> --
> >>> yhttps://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >>>
> >>>>
> >>>> Wishful thinking duly noted. The development, deployment and
> >>>> long-term flight experience of aircraft takes time. Ten years is a
> >>>> good estimate for a single model such as the Antares. Its first
> >>>> flight was in 2003, so development must have started about 20 years
> >>>> ago. I think that in 5 to 10 years we will be thinking "Boy, those
> >>>> electric gliders looked promising at the time, but if we knew then
> >>>> what we know now I would never have bought one." Successful product
> >>>> development just can't be rushed.
> >>>>
> >>> It's not wishful thinking when there are four companies selling
> >>> electric glider power systems:
> >>> Lange, Solo, Pipistrel, and LZ Design (FES). The glider manufacturers
> >>> do not have to design
> >>> their own system, like Antares had to. That speeds development (even
> >>> eliminates it in some
> >>> cases), reduces their cost, and increases reliability.
> >>>
> >>> While the glider market is very small, the main component - batteries
> >>> - is under intense
> >>> development by major corporations around the world. We will benefit
> >>> from this investment,
> >>> without investing a dime in it.
> >>>
> >>> As for glider pilots feeling sorry for their current electric choices
> >>> in 5 or 10 years, well,
> >>> I'm going to suggest many glider pilots will be feeling sorry for
> >>> their current gas engine
> >>> choices ;^)
> >>> --
> >>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
> >>> email me)
> >>> - "A Guide to Self-Launching Sailplane Operation"
> >>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >>>
> >>
> >> Predicting the future is ALWAYS wishful thinking. If you could
> >> actually do it reliably you would be a billionaire. Having four
> >> companies doing it doesn't mean the development is 4 times as fast,
> >> you just get 4 possible failures instead of one.
> >>
> >> There are already some pieces of "common wisdom" that have been
> >> debunked. One is that electric is inherently more reliable than ICE.
> >> The fire incidents are of greatest concern. Dave's issues with his
> >> Antares are also troubling - systems that are dependent on complex
> >> software can have failure modes that are only found by extensive
> >> testing. I know of another Antares owner who had to fly a technician
> >> over from Germany to fix the problems with his glider. And the small
> >> numbers of electric gliders means that buyers will ultimately do most
> >> of the testing themselves. Long term support of these complex systems
> >> is yet another question.
> >>
> > I apologize to all readers for the repetition: The Antares was a
> > pioneering effort, and you can recognize a pioneer by the arrows in his
> > back. Schleicher, Schempp-Hirth, Jonkers, and others, are not following
> > the Antares path. They are not pioneers, but cautious "settlers" that
> > follow after the pioneers have showed them where to go.
> >
> > There are far more FES gliders flying than Antares, and very
> > successfully. The problems that occur are solved by LZ Design, not the
> > glider manufacturers. The eglider segment of gliding has reached the
> > "specialization" stage, and to talk about Dave's Antares problems is to
> > miss the future because you are focusing on a pioneering glider designed
> > and built almost two decades ago.
> >
> > The future, which is now, includes mast-mounted options from several
> > manufacturers. The "old" manufacturers got old by not being too bold:
> > they are cautious, risk-adverse companies that see a burgeoning
> > opportunity they have to join. There will not be fleets of egliders from
> > these companies 5 or 10 years from now, sitting on the ground, unused.
> >
> > I've seen this happen before, with the ASH26E (my current glider), which
> > was quite bold in 1994: the first retracting self-launching sailplane
> > from Schleicher, using a Wankel engine, and - horrors - only a 18m
> > wingspan when there was no 18M class! There were problems, especially in
> > the first 5 years, but they made it work, didn't they? You've owned one!
> > And they (and the other manufacturers) will make the egliders work, and
> > work well.
> >
> Don't think anybody is going to predict the future five years out.
> Maybe there will be some big breakthrough in batteries, maybe not.
>
> FES gliders have been out almost 10 years now, what is clear is their
> history. Underpowered back then, underpowered still today. Makes you
> wonder where these huge improvements in capacity are hiding. Some are
> being sold as self launchers, even when flown as sustainers they're
> still landing out.
>
> CNN proclaimed back in 2017 that lilium was just around the corner.
> Four years later, they have one burned up prototype, another one that
> hasn't flown, and now they're saying they didn't really intend to
> certify that design anyway. Huge shock for Herb, but not everything you
> hear on CNN is true.
>
> The electric beaver folks have been awful quiet after demonstrating a
> single three minute flight. They claimed they were going to be in
> commercial operation in 2022. Uh-huh. Not sure why you'd certify a
> passenger plane that has no room left for passengers. Made for lots of
> phony press releases though.
>
> The Alice in Wonderland folks burned up their prototype last year, now
> they're back with a radically different airframe design, and claiming
> first flight will be in 2021. You betcha. Maybe they burned that proto
> because the knew it never was going to fly? They did have a fire engine
> standing by.
>
> The electric Caravan folks fried their inverter during their big demo
> flight, put the turbine back on it and are trying to sell it.
>
> Maybe electrics will make huge progress, wouldn't that be great? But
> I'm not going to lose any sleep over it. Nor am I excited about the
> current offerings.
Dave, I'm honored to yet a mention from you! You wouldn't believe how little CNN I watch but who cares? Regarding batteries, I have flown RC with most of the available chemistries for the last 20 years and the improvements are mostly in motors, controllers and max discharge amperages as well as slightly more battery cycles vs. earlier times. Still, you are lucky to get 50-100 cycles out of the now listed 50-80C LiPo batteries we fly in RC. Nothing on the horizon that even promises a doubling of capacity. Give me a self-launcher that replaces the tow plane (2k-3k launch) and lets me replace the low cost but fire-safe batteries easily. I'd be interested.

Herb, J7

Eric Greenwell[_4_]

March 6th 21, 06:00 PM

Herbert Kilian wrote on 3/6/2021 7:13 AM:
> Still, you are lucky to get 50-100 cycles out of the now listed 50-80C LiPo batteries we fly in RC. Nothing on the horizon that even promises a doubling of capacity. Give me a self-launcher that replaces the tow plane (2k-3k launch) and lets me replace the low cost but fire-safe batteries easily. I'd be interested.

The glider discharge currents are nowhere near 50-80 times capacity, but more in the 4C range,
so the number of cycles should be much higher; also, you would rarely go to full discharge
(more like 20%-40%) during each flight, which also increases cycle life substantially.

I'm not sure what "replace easily" means: if daily to swap out batteries for charging, then the
fuselage mounted batteries like the FES gliders or Jonkers JS3 RES (mast mounted motor) is what
you need; if it's replacing worn-out batteries every 5-10+ years, I think all of them allow
that in less than a day.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Kenn Sebesta

March 6th 21, 06:31 PM

> The glider discharge currents are nowhere near 50-80 times capacity, but more in the 4C range,
> so the number of cycles should be much higher; also, you would rarely go to full discharge
> (more like 20%-40%) during each flight, which also increases cycle life substantially.

Yes... and no. If you're only going for a single launch, then ideally your pack would be at 20% SoC at the end of the launch. After all, the reserve capacity isn't valuable if you never use it. Assuming 600fpm, and a 2k launch, that yields about 15C as the target discharge rate.

The reason why we have big battery packs in eGliders right now is because 15C is too much discharge for Li-ion technologies. So the pack manufacturers have to make them 3x bigger to get the current to a 4-5C discharge rate. The manufacturers now have a big, heavy, and expensive pack in the plane, but with a lot of reserve capacity. All is not lost, though-- that reserve capacity can be used for sustainer or saves.

Currently, batteries are improving extremely rapidly in ways which are highly relevant to eGliders. The energy density might not be going up very quickly, but we simply don't need it. At 200-250kWhr/kg, we need about 1kg of battery to launch 30kg of glider, so doubling the energy density is only going to shave a few kg off the overall weight. We're already in the realm of diminishing returns at that point.

What we need is power density in a (fire) safe package:

* Li-ions are quite safe, and LiPos are reasonably safe. LiPos are getting safer by the day.
* LiPos far exceed the required power density, and Li-ions are getting there.

As it's not a moonshot to ask for a mild convergence of two sibling technologies, I feel we'll continue to see tangible improvement in the next couple years.We might not see that in the mainstream manufacturers, as they've already locked in their packs and will not be able to change for the foreseeable future, but small projects such as in the aforementioned eGlider group are iterating rapidly.

On Saturday, March 6, 2021 at 10:13:38 AM UTC-5, Herbert Kilian wrote:
> Still, you are lucky to get 50-100 cycles out of the now listed 50-80C LiPo batteries we fly in RC. Nothing on the horizon that even promises a doubling of capacity. Give me a self-launcher that replaces the tow plane (2k-3k launch) and lets me replace the low cost but fire-safe batteries easily. I'd be interested.

This is one of the open questions. Do we really want to have an hour cruise left over, or is the biggest value just getting in the air at all?

I predict that people just want to launch. If we can use 8-10kg of 20C LiPos to get to 1k', with 5 minutes of cruise left over, and a freshly charged pack waiting on the ground, then it's basically a winch launch. And as those of us who have flown in the EU know, winch launches are great ways to get flying.

Eric Greenwell[_4_]

March 6th 21, 07:03 PM

Kenn Sebesta wrote on 3/6/2021 10:31 AM:
> I predict that people just want to launch. If we can use 8-10kg of 20C LiPos to get to 1k', with 5 minutes of cruise left over, and a freshly charged pack waiting on the ground, then it's basically a winch launch. And as those of us who have flown in the EU know, winch launches are great ways to get flying.

I know people want much more than a launch! Note that sustainers are sold by all the major
manufacturers; actually, pretty much all the manufacturers. A company (LZ Design/FES) arose to
service that market electrically. A corollary to your density remarks is doubling the battery
capacity of that "launch only" glider won't add significant weight or cost, and would enable a
couple of saves or a self retrieve. A launch-only glider with easily swapped batteries might
make sense as a busy club glider where pilots are flying for an hour near the airport, but no
one else will buy one.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Kenn Sebesta

March 6th 21, 08:13 PM

On Saturday, March 6, 2021 at 2:03:25 PM UTC-5, Eric Greenwell wrote:
> Kenn Sebesta wrote on 3/6/2021 10:31 AM:
> > I predict that people just want to launch. If we can use 8-10kg of 20C LiPos to get to 1k', with 5 minutes of cruise left over, and a freshly charged pack waiting on the ground, then it's basically a winch launch. And as those of us who have flown in the EU know, winch launches are great ways to get flying.
> I know people want much more than a launch! Note that sustainers are sold by all the major
> manufacturers; actually, pretty much all the manufacturers.

You might be right! I think we're looking at this same coin from two different sides. I'm at the stage of my gliding career where just getting up and staying up is the goal, whereas you are quite a lot more accomplished and value the ability to get home after a long flight. It's tough for me to guess which direction the larger market needs, we'll see what it ultimately decides. As you point out, it's very easy to adjust the amount of available battery energy.

> A corollary to your density remarks is doubling the battery capacity of that "launch only" glider won't add significant weight or cost, and would enable a couple of saves or a self retrieve.

For sure! Although keep in mind that the battery is the single highest $ component of the propulsion system. Moreover, batteries have a fixed lifespan with or without use, so some people might prefer a lower TCO and a lighter plane. I think the beauty of electric is the ability to tailor this to specific needs. We can even imagine the same plane with a lightweight pattern launch battery, and a heftier XC battery.

The genius of all this is that as battery tech improves the existing plane just gets better and better. When you're looking at your replacement pack 5-10 years down the road you'll automatically benefit from all the improvements and your new pack will either be cheaper, or it'll fly longer, or it'll be lighter. Maybe all three. Certainly never saw 100LL get cheaper, better, and lighter!

Martin Gregorie[_6_]

March 6th 21, 08:26 PM

On Fri, 05 Mar 2021 20:56:50 -0800, jfitch wrote:

> Comparisons of commercial air transport with self launched gliders are
> specious, very different energy use profile. Same with cars vs. self
> launched gliders. In either case though, the energy density difference
> between 100LL and state-of-the-art batteries is hard to ignore - at
> least 30:1 at this moment, and still 10:1 even considering relative
> efficiencies. I've no doubt electrics will eventually take over, the
> question is only if you buy one now, how early are you in the
> development cycle? Once the cycle is mature, there should be a market
> for a drop in electric replacement for aging ICE powerplants on popular
> gliders.
>
Has anybody else on here read David Brin's 'Existence'?

It suggests one way to make mass electric-powered air transport work: Put
the pax and cargo in nice accommodation on a large airship and tow it
cross country behind an electric locomotive running on repurposed AmTrak
tracks.

What he describes is an interesting case of "look ma! No batteries!".

--
Martin | martin at
Gregorie | gregorie dot org

Martin Gregorie[_6_]

March 6th 21, 09:00 PM

On Sat, 06 Mar 2021 12:13:38 -0800, Kenn Sebesta wrote:

> For sure! Although keep in mind that the battery is the single highest $
> component of the propulsion system. Moreover, batteries have a fixed
> lifespan with or without use, so some people might prefer a lower TCO
> and a lighter plane. I think the beauty of electric is the ability to
> tailor this to specific needs. We can even imagine the same plane with a
> lightweight pattern launch battery, and a heftier XC battery.
>
Speaking as a pilot whose launch method of choice is the winch, I think
the way to go could well be an electric sustainer launched with an
electric winch: potentially 100% green and no need for big, heavy
batteries.

However, launching an electric sustainer with a Polish gravity launch
would be super-cool.

> The genius of all this is that as battery tech improves the existing
> plane just gets better and better.
>
All the practical battery chemistries have been tried by now and their
specific energy capacities are well-known, so I suspect that future
improvement will be along the lines of incremental weight reduction,
better durability and, possibly, price reduction as recycling techniques
are improved. OTOH if battery recycling doesn't become very close to zero
loss for the active material in a battery, prices will rise as mines get
worked out, and IIRC the reserves of these sources are fairly well-
known.

Questions we need to know the answers for very soon are:

- How widespread is battery material recycling at present?

- Can you yet buy a battery containing recycled Lithium?

- If not, why not?

--
Martin | martin at
Gregorie | gregorie dot org

Mark Mocho

March 7th 21, 12:44 PM

It suggests one way to make mass electric-powered air transport work: Put
the pax and cargo in nice accommodation on a large airship and tow it
cross country behind an electric locomotive running on repurposed AmTrak
tracks.

And just what happens when the train goes under a bridge?

Another unicorn inspired idea. Keep 'em coming. I need the laughs.

Martin Gregorie[_6_]

March 7th 21, 01:31 PM

On Sun, 07 Mar 2021 04:44:36 -0800, Mark Mocho wrote:

> It suggests one way to make mass electric-powered air transport work:
> Put the pax and cargo in nice accommodation on a large airship and tow
> it cross country behind an electric locomotive running on repurposed
> AmTrak tracks.
>
> And just what happens when the train goes under a bridge?
>
> Another unicorn inspired idea. Keep 'em coming. I need the laughs.

The author is a bit more than a unicorn, methinks. He's well-regarded in
technical circles.

Anyhow, if such a system was set up it could obviously only work on lines
that have no tunnels and that don't run in deep valleys (so not on the
Glendale-Denver line obviously), and that have been 'adjusted' so that
the line is always at the top of the crossing stack.

It would also be faster than the old Goon Show concept of horse-drawn
zeppelins.

--
Martin | martin at
Gregorie | gregorie dot org

Mark Mocho

March 7th 21, 02:38 PM

> It would also be faster than the old Goon Show concept of horse-drawn
> zeppelins.

Yes, it would effectively take the speed and omnidirectional attribute of air travel and relegate it to the pathways and speed range of a railroad. And only if you can find a rail line that has no tunnels, bridges or power transmission lines crossing it. And you now eliminate travel to destinations that have no existing rail lines.

It's like taking a wireless voice communication system and turning it into a teletype. Oh, wait- That's the iPhone.

Being well-regarded in technical circles does not necessarily mean you won't come up with a bad idea once in a while.

Next up: How to make an ASG-29 perform like a paraglider.

Martin Gregorie[_6_]

March 7th 21, 03:23 PM

On Sun, 07 Mar 2021 06:38:22 -0800, Mark Mocho wrote:

> Being well-regarded in technical circles does not necessarily mean you
> won't come up with a bad idea once in a while.
>
Indeed, IME his SF varies in quality and ingenuity: some (Earth, Sundiver
plus the next two followups, Kil'n People, The Practise Effect) were
excellent, the others including Existence, not so much.

> Next up: How to make an ASG-29 perform like a paraglider.
>
Good luck with that: I'd settle for a new build carbon Libelle.

--
Martin | martin at
Gregorie | gregorie dot org

Eric Greenwell[_4_]

March 7th 21, 04:24 PM

Mark Mocho wrote on 3/7/2021 6:38 AM:
>
> Next up: How to make an ASG-29 perform like a paraglider.
>
I have dreams like that. It makes the off-field landings so much easier, way better than the
already very good high-deflection landing flaps. I envy birds for their STOL skills, and wish
our gliders could emulate them. The closest we've come might be the 90 degree flaps like Dick
Schreder used, or the BRS parachutes.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Moshe Braner

March 7th 21, 10:07 PM

On 3/7/2021 8:31 AM, Martin Gregorie wrote:
> On Sun, 07 Mar 2021 04:44:36 -0800, Mark Mocho wrote:
>
>> It suggests one way to make mass electric-powered air transport work:
>> Put the pax and cargo in nice accommodation on a large airship and tow
>> it cross country behind an electric locomotive running on repurposed
>> AmTrak tracks.
>>
>> And just what happens when the train goes under a bridge?
>>
>> Another unicorn inspired idea. Keep 'em coming. I need the laughs.
>
> The author is a bit more than a unicorn, methinks. He's well-regarded in
> technical circles.
>
> Anyhow, if such a system was set up it could obviously only work on lines
> that have no tunnels and that don't run in deep valleys (so not on the
> Glendale-Denver line obviously), and that have been 'adjusted' so that
> the line is always at the top of the crossing stack.
>
> It would also be faster than the old Goon Show concept of horse-drawn
> zeppelins.
>

Or you can use the newfangled idea of making that airship very narrow
and fly it very low to the ground so it can go under the bridges and
through tunnels. Oh wait...

While the rest of the world has double-tracked and electrified their
long-range railroads (e.g., the trans-Siberia), here in the US we sit on
our heels while a few loonies play with "pods" and other nonsense.

But I'm getting further off topic. Gliders are nice. They don't need
no steenkin' engines.

Eric Greenwell[_4_]

March 7th 21, 11:08 PM

Moshe Braner wrote on 3/7/2021 2:07 PM:
> But I'm getting further off topic.* Gliders are nice.* They don't need no steenkin' engines.

Alright! Back to Basics: bungey launch! Or is it still OK to use electric motors? No steenk there.
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

John Galloway[_2_]

March 7th 21, 11:18 PM

On Sunday, 7 March 2021 at 22:04:16 UTC, Moshe Braner wrote:
> On 3/7/2021 8:31 AM, Martin Gregorie wrote:
> > On Sun, 07 Mar 2021 04:44:36 -0800, Mark Mocho wrote:
> >
> >> It suggests one way to make mass electric-powered air transport work:
> >> Put the pax and cargo in nice accommodation on a large airship and tow
> >> it cross country behind an electric locomotive running on repurposed
> >> AmTrak tracks.
> >>
> >> And just what happens when the train goes under a bridge?
> >>
> >> Another unicorn inspired idea. Keep 'em coming. I need the laughs.
> >
> > The author is a bit more than a unicorn, methinks. He's well-regarded in
> > technical circles.
> >
> > Anyhow, if such a system was set up it could obviously only work on lines
> > that have no tunnels and that don't run in deep valleys (so not on the
> > Glendale-Denver line obviously), and that have been 'adjusted' so that
> > the line is always at the top of the crossing stack.
> >
> > It would also be faster than the old Goon Show concept of horse-drawn
> > zeppelins.
> >
> Or you can use the newfangled idea of making that airship very narrow
> and fly it very low to the ground so it can go under the bridges and
> through tunnels. Oh wait...
>
> While the rest of the world has double-tracked and electrified their
> long-range railroads (e.g., the trans-Siberia), here in the US we sit on
> our heels while a few loonies play with "pods" and other nonsense.
>
> But I'm getting further off topic. Gliders are nice. They don't need
> no steenkin' engines.

I have yet to see a glider take off (bungee launches excepted) or return from a field without an engine.

Mark Mocho

March 8th 21, 12:40 AM

> I have yet to see a glider take off (bungee launches excepted) or return from a field without an engine.

Does the one in the tow vehicle count?

Tom BravoMike

March 8th 21, 01:48 AM

> > I have yet to see a glider take off (bungee launches excepted) or return from a field without an engine.

See and believe:
https://youtu.be/_JNg9zwvDkI?list=PLC40EB4949AD5395B

Been there, done that. With a favorable wind one circle was enough to get high over the heads of the observers at the gravity launch site, and hours long ridge/wave soaring was possible.

BTW, Bezmiechowa is the place where Wanda Modlibowska set a new women's duration record of 24 hours 14 minutes in May 1937. When I was there for the first time, other pilots from our group did night ridge soaring in a 'Bocian' glider (by design equipped with position lights). The ridge line was marked with a series of campfires.

In 1993-95 night flights were still part of the training for licensed glider pilots in some places in Poland. Happy to have that exotic (and extinct?) endorsement in my logbook.

Just keen memories in a thread about dreams about self-launching gliders (in expectation of a new soaring season).

Moshe Braner

March 8th 21, 02:04 AM

On 3/7/2021 6:08 PM, Eric Greenwell wrote:
> Moshe Braner wrote on 3/7/2021 2:07 PM:
>> But I'm getting further off topic.Â* Gliders are nice.Â* They don't need
>> no steenkin' engines.
>
> Alright! Back to Basics: bungey launch! Or is it still OK to use
> electric motors? No steenk there.

Lighten up, Eric and others. I was just saying that in gliders we don't
need to be dragged cross-country by a locomotive. I have nothing
against launching by some motorized thing or another.

And back to the topic, we have some people who believe all the hype from
Saint Elon about new batteries etc, and others who are more skeptical.
But we all revel in what has been achieved in electric glider launching
and sustaining, and hope for more. It's a lot more feasible than
electric air transport.

Personally I think that dragging an expensive battery pack along in
every glider is inefficient use of resources. But then you may say the
same about dragging equally, if not more, expensive composite structures
around the sky. We do what we have to do to achieve our aerial dance
performances. Then we land, and like any performance art, it's all gone
poof, into the past. We only do it because we love it.

March 8th 21, 04:30 AM

On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > your potential retrieve distance is shorter, instead of an imminent landing.
> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
>
> I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>
> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.

Why don't you start by naming JUST ONE that replaced an ICE with an electric.

Tom

Eric Greenwell[_4_]

March 8th 21, 04:49 AM

Tom BravoMike wrote on 3/7/2021 5:48 PM:
>
>>> I have yet to see a glider take off (bungee launches excepted) or return from a field without an engine.
>
> See and believe:
> https://youtu.be/_JNg9zwvDkI?list=PLC40EB4949AD5395B
>
> Been there, done that. With a favorable wind one circle was enough to get high over the heads of the observers at the gravity launch site, and hours long ridge/wave soaring was possible.
>
> BTW, Bezmiechowa is the place where Wanda Modlibowska set a new women's duration record of 24 hours 14 minutes in May 1937. When I was there for the first time, other pilots from our group did night ridge soaring in a 'Bocian' glider (by design equipped with position lights). The ridge line was marked with a series of campfires.
>
> In 1993-95 night flights were still part of the training for licensed glider pilots in some places in Poland. Happy to have that exotic (and extinct?) endorsement in my logbook.
>
> Just keen memories in a thread about dreams about self-launching gliders (in expectation of a new soaring season).
>
Bungee AND gravity launch! Yahoo!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric Greenwell[_4_]

March 8th 21, 04:52 AM

2G wrote on 3/7/2021 8:30 PM:
> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
>>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
>>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
>>> your potential retrieve distance is shorter, instead of an imminent landing.
>> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
>>
>> I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>>
>> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
>
> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
>
> Tom
>
Hank Nixon.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

March 8th 21, 05:06 AM

On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
> 2G wrote on 3/7/2021 8:30 PM:
> > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> >>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> >>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> >>> your potential retrieve distance is shorter, instead of an imminent landing.
> >> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
> >>
> >> I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> >>
> >> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> >
> > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> >
> > Tom
> >
> Hank Nixon.
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
And what was the glider?

Charlie M. (UH & 002 owner/pilot)

March 8th 21, 11:43 AM

On Monday, March 8, 2021 at 12:06:57 AM UTC-5, 2G wrote:
> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
> > 2G wrote on 3/7/2021 8:30 PM:
> > > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > >>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > >>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > >>> your potential retrieve distance is shorter, instead of an imminent landing.
> > >> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
> > >>
> > >> I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > >>
> > >> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> > >
> > > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> > >
> > > Tom
> > >
> > Hank Nixon.
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> And what was the glider?
ASW-24e

Eric Greenwell[_4_]

March 8th 21, 01:25 PM

2G wrote on 3/7/2021 9:06 PM:
> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
>> 2G wrote on 3/7/2021 8:30 PM:
>>> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
>>>>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
>>>>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
>>>>> your potential retrieve distance is shorter, instead of an imminent landing.
>>>> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
>>>>
>>>> I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>>>>
>>>> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
>>>
>>> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
>>>
>>> Tom
>>>
>> Hank Nixon.
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> And what was the glider?
>
Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
some details from Hank:

Some data from first hand experience:
ASW-24E converted to electric from 2 cycle Rotax gas.
Power system including all items is right at 100 lb added to pure sailplane airframe weight.
This is a pylon mounted retractable system.
Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
Your cost estimate is a bit less than1/2 what it would require for parts, not including items
required to do the airframe conversion and assuming the person doing this can fabricate
required items, engineer and wire the system, design and construct the prop, etc.
This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
process. Of those I am aware of that have done ,or are doing this, nobody has had that good
fortune.
FWIW
UH

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric Greenwell[_4_]

March 8th 21, 01:41 PM

Moshe Braner wrote on 3/7/2021 6:04 PM:
> Personally I think that dragging an expensive battery pack along in every glider is inefficient
> use of resources.* But then you may say the same about dragging equally, if not more, expensive
> composite structures around the sky.* We do what we have to do to achieve our aerial dance
> performances.* Then we land, and like any performance art, it's all gone poof, into the past.
> We only do it because we love it.

I think having towplanes sit idle on the ground Monday through Friday is an inefficient use of
resources; ditto for tow planes sitting idle in poor weather, while I'm 100 miles away, looking
at growing cumulus.

But, I agree with the basic point that sharing the launch system is a more efficient use of
resources, and a way to do that with a self-launcher is a partnership, especially with partners
that have different or flexible schedules. Electric self-launchers seem particularly
well-suited to partnerships, with their easier use of the motor.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Moshe Braner

March 8th 21, 03:20 PM

On 3/8/2021 8:41 AM, Eric Greenwell wrote:
> Moshe Braner wrote on 3/7/2021 6:04 PM:
>> Personally I think that dragging an expensive battery pack along in
>> every glider is inefficient use of resources.Â* But then you may say
>> the same about dragging equally, if not more, expensive composite
>> structures around the sky.Â* We do what we have to do to achieve our
>> aerial dance performances.Â* Then we land, and like any performance
>> art, it's all gone poof, into the past. We only do it because we love it.
>
> I think having towplanes sit idle on the ground Monday through Friday is
> an inefficient use of resources; ditto for tow planes sitting idle in
> poor weather, while I'm 100 miles away, looking at growing cumulus.
>
> But, I agree with the basic point that sharing the launch system is a
> more efficient use of resources, and a way to do that with a
> self-launcher is a partnership, especially with partners that have
> different or flexible schedules. Electric self-launchers seem
> particularly well-suited to partnerships, with their easier use of the
> motor.

If battery packs were standardized and removable (better for charging
anyway), then could also share them between gliders. Of course on the
day when the weather is really good everybody will be competing for the
use of the shared battery. Plug several shared standard batteries into
the electric winch on that day? ("Blue Sky" thinking here...)

March 9th 21, 01:15 AM

On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
> 2G wrote on 3/7/2021 9:06 PM:
> > On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
> >> 2G wrote on 3/7/2021 8:30 PM:
> >>> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> >>>>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> >>>>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> >>>>> your potential retrieve distance is shorter, instead of an imminent landing.
> >>>> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
> >>>>
> >>>> I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> >>>>
> >>>> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> >>>
> >>> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> >>>
> >>> Tom
> >>>
> >> Hank Nixon.
> >> --
> >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >> - "A Guide to Self-Launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > And what was the glider?
> >
> Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
> thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
> some details from Hank:
>
> Some data from first hand experience:
> ASW-24E converted to electric from 2 cycle Rotax gas.
> Power system including all items is right at 100 lb added to pure sailplane airframe weight.
> This is a pylon mounted retractable system.
> Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
> Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
> Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
> Your cost estimate is a bit less than1/2 what it would require for parts, not including items
> required to do the airframe conversion and assuming the person doing this can fabricate
> required items, engineer and wire the system, design and construct the prop, etc.
> This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
> process. Of those I am aware of that have done ,or are doing this, nobody has had that good
> fortune.
> FWIW
> UH
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

This glider was converted from a sustainer to a self-launcher, apparently to provide a capability it did not have before and not because the engine did not perform as intended.

Tom

March 9th 21, 01:19 AM

On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
> On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
> > 2G wrote on 3/7/2021 9:06 PM:
> > > On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
> > >> 2G wrote on 3/7/2021 8:30 PM:
> > >>> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > >>>>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > >>>>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > >>>>> your potential retrieve distance is shorter, instead of an imminent landing.
> > >>>> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
> > >>>>
> > >>>> I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > >>>>
> > >>>> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> > >>>
> > >>> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> > >>>
> > >>> Tom
> > >>>
> > >> Hank Nixon.
> > >> --
> > >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > >> - "A Guide to Self-Launching Sailplane Operation"
> > >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > > And what was the glider?
> > >
> > Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
> > thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
> > some details from Hank:
> >
> > Some data from first hand experience:
> > ASW-24E converted to electric from 2 cycle Rotax gas.
> > Power system including all items is right at 100 lb added to pure sailplane airframe weight.
> > This is a pylon mounted retractable system.
> > Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
> > Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
> > Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
> > Your cost estimate is a bit less than1/2 what it would require for parts, not including items
> > required to do the airframe conversion and assuming the person doing this can fabricate
> > required items, engineer and wire the system, design and construct the prop, etc.
> > This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
> > process. Of those I am aware of that have done ,or are doing this, nobody has had that good
> > fortune.
> > FWIW
> > UH
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> This glider was converted from a sustainer to a self-launcher, apparently to provide a capability it did not have before and not because the engine did not perform as intended.
>
> Tom

Also, Hank concluded with this piece of advice:

"To my knowledge this has been done once so far in the US .
If you want an electric sailplane- buy one."

Sounds prudent to me.

Tom

Eric Greenwell[_4_]

March 9th 21, 03:51 AM

2G wrote on 3/8/2021 5:19 PM:
> On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
>> On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
>>> 2G wrote on 3/7/2021 9:06 PM:
>>>> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
>>>>> 2G wrote on 3/7/2021 8:30 PM:
>>>>>> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
>>>>>>>> A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
>>>>>>>> gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
>>>>>>>> your potential retrieve distance is shorter, instead of an imminent landing.
>>>>>>> I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive..
>>>>>>>
>>>>>>> I would not expect anyone to be deploying this technology anytime soon.. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
>>>>>>>
>>>>>>> Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market.. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
>>>>>>
>>>>>> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
>>>>>>
>>>>>> Tom
>>>>>>
>>>>> Hank Nixon.
>>>>> --
>>>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>>>>> - "A Guide to Self-Launching Sailplane Operation"
>>>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>> And what was the glider?
>>>>
>>> Hank has posted about the glider a number of times on RAS. Search for "Nixon", or look in the
>>> thread "What is involved regulation wise adding an electric motor to a glider?" Here is are
>>> some details from Hank:
>>>
>>> Some data from first hand experience:
>>> ASW-24E converted to electric from 2 cycle Rotax gas.
>>> Power system including all items is right at 100 lb added to pure sailplane airframe weight.
>>> This is a pylon mounted retractable system.
>>> Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
>>> Climb rate at 160 amps is 300 ft/minute. Actual power delivered is about 16kw.
>>> Climb rate at 230 amps is 500 ft/minute. Actual power delivered is about 23kw at this time
>>> Your cost estimate is a bit less than1/2 what it would require for parts, not including items
>>> required to do the airframe conversion and assuming the person doing this can fabricate
>>> required items, engineer and wire the system, design and construct the prop, etc.
>>> This assumes perfect efficiency and nothing destroyed or scrapped going through the learning
>>> process. Of those I am aware of that have done ,or are doing this, nobody has had that good
>>> fortune.
>>> FWIW
>>> UH
>>> --
>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>>> - "A Guide to Self-Launching Sailplane Operation"
>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>> This glider was converted from a sustainer to a self-launcher, apparently to provide a capability it did not have before and not because the engine did not perform as intended.
>>
>> Tom
>
> Also, Hank concluded with this piece of advice:
>
> "To my knowledge this has been done once so far in the US .
> If you want an electric sailplane- buy one."
>
> Sounds prudent to me.

Some people like the challenge, much as glider pilots do in their flying (or they'd get an
airplane): Ken Sebesta, a participant here, has removed the self-launching gas motor from his
AC-5 Russia and is replacing it with an electric motor. I believe he's bench-tested the motor,
ESC, and batteries, and is now working out the motor mounting details.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Dan Marotta

March 9th 21, 03:42 PM

I just gotta ask, "Why"?

What is the cost of the conversion? Is the engine failed and not
repairable? Are there a lot of brownie points for "saving the planet"?

If I wanted to, my gas powered Stemme could reach just about anywhere in
the western states on a single tank of gas. The electric offerings from
Stemme have great range at the expense of carrying a gas-powered
generator along to make the electric power to run the motor. Where's
the advantage?

Dan
5J

On 3/8/21 8:51 PM, Eric Greenwell wrote:
> 2G wrote on 3/8/2021 5:19 PM:
>> On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
>>> On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
>>>> 2G wrote on 3/7/2021 9:06 PM:
>>>>> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
>>>>>> 2G wrote on 3/7/2021 8:30 PM:
>>>>>>> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
>>>>>>>>> A hybrid system with a gas engine wouldn't have the pucker
>>>>>>>>> factor associated with starting a
>>>>>>>>> gas powered motorglider to avoid a landing: if the hybrid
>>>>>>>>> engine doesn't start, it just means
>>>>>>>>> your potential retrieve distance is shorter, instead of an
>>>>>>>>> imminent landing.
>>>>>>>> I'll wade in here with some experience. Top Flight, a Boston
>>>>>>>> startup specializing in hybrid propulsion systems, spend over
>>>>>>>> half a decade developing their power unit. The hardest part for
>>>>>>>> them was developing a unit which was reliable. Motors don't like
>>>>>>>> vibration and they don't like heat. Combine the two together and
>>>>>>>> the motor is not long for this world. It took a lot more R&D
>>>>>>>> than anyone expected to make a lightweight package which could
>>>>>>>> survive..
>>>>>>>>
>>>>>>>> I would not expect anyone to be deploying this technology
>>>>>>>> anytime soon.. If and when it is commercialized, it will be
>>>>>>>> useful for ferry flights of electric aircraft. For any use which
>>>>>>>> requires permanent installation, you're probably better having
>>>>>>>> it drive the propeller directly.
>>>>>>>>
>>>>>>>> Re: eGliders, I sense a tone here which is reminiscent of
>>>>>>>> discussions about finally putting the 2-33 to rest. The US is no
>>>>>>>> longer the forefront of light aviation, so we need to look east
>>>>>>>> to see what the trends are. We know that leading glider
>>>>>>>> manufacturers are racing to bring eGliders to market.. A
>>>>>>>> gentleman who works on glider competition rules noted this
>>>>>>>> summer that glider records are falling left and right to
>>>>>>>> eGliders. There is a growing group of amateurs who are pulling
>>>>>>>> their engines out of their gas self-launchers and replacing them
>>>>>>>> with electric (If you'd like to be a part of this group, DM me).
>>>>>>>> The future was yesterday, but like any future it doesn't arrive
>>>>>>>> at all places at once.
>>>>>>>
>>>>>>> Why don't you start by naming JUST ONE that replaced an ICE with
>>>>>>> an electric.
>>>>>>>
>>>>>>> Tom
>>>>>>>
>>>>>> Hank Nixon.
>>>>>> --
>>>>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us"
>>>>>> to email me)
>>>>>> - "A Guide to Self-Launching Sailplane Operation"
>>>>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>>>>
>>>>> And what was the glider?
>>>>>
>>>> Hank has posted about the glider a number of times on RAS. Search
>>>> for "Nixon", or look in the
>>>> thread "What is involved regulation wise adding an electric motor to
>>>> a glider?" Here is are
>>>> some details from Hank:
>>>>
>>>> Some data from first hand experience:
>>>> ASW-24E converted to electric from 2 cycle Rotax gas.
>>>> Power system including all items is right at 100 lb added to pure
>>>> sailplane airframe weight.
>>>> This is a pylon mounted retractable system.
>>>> Battery is 120 volt,4.9 kwh lithium ion weighing 60 lb.
>>>> Climb rate at 160 amps is 300 ft/minute. Actual power delivered is
>>>> about 16kw.
>>>> Climb rate at 230 amps is 500 ft/minute. Actual power delivered is
>>>> about 23kw at this time
>>>> Your cost estimate is a bit less than1/2 what it would require for
>>>> parts, not including items
>>>> required to do the airframe conversion and assuming the person doing
>>>> this can fabricate
>>>> required items, engineer and wire the system, design and construct
>>>> the prop, etc.
>>>> This assumes perfect efficiency and nothing destroyed or scrapped
>>>> going through the learning
>>>> process. Of those I am aware of that have done ,or are doing this,
>>>> nobody has had that good
>>>> fortune.
>>>> FWIW
>>>> UH
>>>> --
>>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>>>> email me)
>>>> - "A Guide to Self-Launching Sailplane Operation"
>>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>>
>>> This glider was converted from a sustainer to a self-launcher,
>>> apparently to provide a capability it did not have before and not
>>> because the engine did not perform as intended.
>>>
>>> Tom
>>
>> Also, Hank concluded with this piece of advice:
>>
>> "To my knowledge this has been done once so far in the US .
>> If you want an electric sailplane- buy one."
>>
>> Sounds prudent to me.
>
> Some people like the challenge, much as glider pilots do in their flying
> (or they'd get an airplane): Ken Sebesta, a participant here, has
> removed the self-launching gas motor from his AC-5 Russia and is
> replacing it with an electric motor. I believe he's bench-tested the
> motor, ESC, and batteries, and is now working out the motor mounting
> details.
>
>

John Johnson

March 9th 21, 06:36 PM

Enjoying this thread. I'm a newbie - flying XC for about a year now. I definitely would like self-launch capability and just some 'modest' sustaining capacity left over. My land outs and close calls to-date could have all been mitigated by 10min (or less) of sustaining assist. If I fly so deep into marginal conditions that I need an hour of power to get home, I must have really made some bad decisions. Soaring conditions here in southern AZ are pretty great but land out options can be challenging. I see sustaining needs as more about dealing with localized exceptions and improving your land out choices. If I needed >1 launch or >10-15min flight time, I don't think the conditions were aligned for the XC flight I was looking for anyway.

Example: I was recently surprised by continuous 7-9kt sink over a 15mi final glide. I started out with a 3200' agl arrival altitude cushion and watched it drop to <200ft as I soldiered home and left my last favorable LO options behind. I was stuck looking at an emergency bailout on a mine tailing that has generated a number of scary tales in my club. I was lucky to find some lift off a local feature just 2mi out and got enough altitude to make the field in good shape. 2-3min of powered sustaining flight would have made that a non-event.

One launch and some modest assist capacity would be awesome and fit my primary goals:
- independent launch capability
- backup for the times I need a short boost to avoid a land out or help get me to a safer land out option
- I'm ok with landing out on occasion if its safe and retrievable
- Really prefer electric over ICE

Seems like the current mast-mounted electric technology is just about there for my goals. It's now more about solution maturity, track record, and $$ as I watch how things shake out. I do, however, want hear about alternate use models and scenarios that could affect my decisions.

JJ

Eric Greenwell[_4_]

March 9th 21, 07:25 PM

Dan Marotta wrote on 3/9/2021 7:42 AM:
> I just gotta ask, "Why"?
>
> What is the cost of the conversion?* Is the engine failed and not repairable? Are there a lot
> of brownie points for "saving the planet"?
>
> If I wanted to, my gas powered Stemme could reach just about anywhere in the western states on
> a single tank of gas.* The electric offerings from Stemme have great range at the expense of
> carrying a gas-powered generator along to make the electric power to run the motor.* Where's
> the advantage?
>
> Dan
Don't take it personally :^) Kenn is converting an AC-5 Russia, a WAY DIFFERENT glider than the
Stemme! It has a rattlely, unreliable motor of modest power, but I'll let Kenn fill in the details
of his decision.
>
> On 3/8/21 8:51 PM, Eric Greenwell wrote:
>> 2G wrote on 3/8/2021 5:19 PM:
>>> On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
>>>> On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
>>>>> 2G wrote on 3/7/2021 9:06 PM:
>>>>>> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
...
>>>
>>> Also, Hank concluded with this piece of advice:
>>>
>>> "To my knowledge this has been done once so far in the US .
>>> If you want an electric sailplane- buy one."
>>>
>>> Sounds prudent to me.
>>
>> Some people like the challenge, much as glider pilots do in their flying (or they'd get an
>> airplane): Ken Sebesta, a participant here, has removed the self-launching gas motor from his
>> AC-5 Russia and is replacing it with an electric motor. I believe he's bench-tested the
>> motor, ESC, and batteries, and is now working out the motor mounting details.
>>
>>

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

jfitch

March 9th 21, 08:55 PM

If you are thinking of a motorglider as saving you from an unsafe landout, you are a Statistic - In -Waiting. What a motorglider does is save you the inconvenience of a safe landout and retrieve. If anything, it makes landouts more dangerous, as the pilot workload at a critical point increases (and this is an argument for electric, which typically takes less attention). A motorglider does not increase your range over unlandable terrain, or improve your chances for a safe landout (not reliably, anyway). Your example of continuous 7 - 9 knot sink for example, would be turned into continuous 5 - 7 knot sink with a typical sustainer, and it would take the most powerful of self launch power plants to turn that into a climb (even if you are lucky enough to have the motor start). A motor is no substitute for intelligent decisions, and it is not a substitute for having an easy glide angle to a safe landing site at all times. I have two friends with motorgliders left in trees that can bear witness.

Regarding who might replace an ICE with electric: I might be a candidate, if my engine were to fail in a way that required replacement. The $30K replacement cost and 6 months waiting time certainly would allow some contemplation. The glider already has doors, a prop, a boom, a jack to deploy the boom, capacity to carry around 150 lbs in a spacious engine bay. All that is left are the hard bits: motor, motor drive, and battery.

On Tuesday, March 9, 2021 at 10:36:11 AM UTC-8, John Johnson wrote:
> Enjoying this thread. I'm a newbie - flying XC for about a year now. I definitely would like self-launch capability and just some 'modest' sustaining capacity left over. My land outs and close calls to-date could have all been mitigated by 10min (or less) of sustaining assist. If I fly so deep into marginal conditions that I need an hour of power to get home, I must have really made some bad decisions. Soaring conditions here in southern AZ are pretty great but land out options can be challenging. I see sustaining needs as more about dealing with localized exceptions and improving your land out choices. If I needed >1 launch or >10-15min flight time, I don't think the conditions were aligned for the XC flight I was looking for anyway.
>
> Example: I was recently surprised by continuous 7-9kt sink over a 15mi final glide. I started out with a 3200' agl arrival altitude cushion and watched it drop to <200ft as I soldiered home and left my last favorable LO options behind. I was stuck looking at an emergency bailout on a mine tailing that has generated a number of scary tales in my club. I was lucky to find some lift off a local feature just 2mi out and got enough altitude to make the field in good shape. 2-3min of powered sustaining flight would have made that a non-event.
>
> One launch and some modest assist capacity would be awesome and fit my primary goals:
> - independent launch capability
> - backup for the times I need a short boost to avoid a land out or help get me to a safer land out option
> - I'm ok with landing out on occasion if its safe and retrievable
> - Really prefer electric over ICE
>
> Seems like the current mast-mounted electric technology is just about there for my goals. It's now more about solution maturity, track record, and $$ as I watch how things shake out. I do, however, want hear about alternate use models and scenarios that could affect my decisions.
>
> JJ

Dan Marotta

March 9th 21, 09:15 PM

I don't take anything on RAS personally any more. I was genuinely
interested in the "why" aspect of the conversion.

Dan
5J

On 3/9/21 12:25 PM, Eric Greenwell wrote:
>
> Dan Marotta wrote on 3/9/2021 7:42 AM:
>> I just gotta ask, "Why"?
>>
>> What is the cost of the conversion?Â* Is the engine failed and not
>> repairable? Are there a lot of brownie points for "saving the planet"?
>>
>> If I wanted to, my gas powered Stemme could reach just about anywhere
>> in the western states on a single tank of gas.Â* The electric offerings
>> from Stemme have great range at the expense of carrying a gas-powered
>> generator along to make the electric power to run the motor.Â* Where's
>> the advantage?
>>
>> Dan
> Don't take it personally :^) Kenn is converting an AC-5 Russia, a WAY
> DIFFERENT glider than the
> Stemme! It has a rattlely, unreliable motor of modest power, but I'll
> let Kenn fill in the details
> of his decision.
>>
>> On 3/8/21 8:51 PM, Eric Greenwell wrote:
>>> 2G wrote on 3/8/2021 5:19 PM:
>>>> On Monday, March 8, 2021 at 5:15:13 PM UTC-8, 2G wrote:
>>>>> On Monday, March 8, 2021 at 5:25:41 AM UTC-8, Eric Greenwell wrote:
>>>>>> 2G wrote on 3/7/2021 9:06 PM:
>>>>>>> On Sunday, March 7, 2021 at 8:52:23 PM UTC-8, Eric Greenwell wrote:
> ...
>>>>
>>>> Also, Hank concluded with this piece of advice:
>>>>
>>>> "To my knowledge this has been done once so far in the US .
>>>> If you want an electric sailplane- buy one."
>>>>
>>>> Sounds prudent to me.
>>>
>>> Some people like the challenge, much as glider pilots do in their
>>> flying (or they'd get an airplane): Ken Sebesta, a participant here,
>>> has removed the self-launching gas motor from his AC-5 Russia and is
>>> replacing it with an electric motor. I believe he's bench-tested the
>>> motor, ESC, and batteries, and is now working out the motor mounting
>>> details.
>>>
>>>
>
>

John Johnson

March 9th 21, 11:53 PM

On Tuesday, March 9, 2021 at 1:55:27 PM UTC-7, jfitch wrote:
> If you are thinking of a motorglider as saving you from an unsafe landout, you are a Statistic - In -Waiting. What a motorglider does is save you the inconvenience of a safe landout and retrieve. If anything, it makes landouts more dangerous, as the pilot workload at a critical point increases (and this is an argument for electric, which typically takes less attention). A motorglider does not increase your range over unlandable terrain, or improve your chances for a safe landout (not reliably, anyway). Your example of continuous 7 - 9 knot sink for example, would be turned into continuous 5 - 7 knot sink with a typical sustainer, and it would take the most powerful of self launch power plants to turn that into a climb (even if you are lucky enough to have the motor start). A motor is no substitute for intelligent decisions, and it is not a substitute for having an easy glide angle to a safe landing site at all times. I have two friends with motorgliders left in trees that can bear witness.
>
Agree with all your points and I don't think I've ever seen a motor related thread that doesn't preach the obvious: don't rely on your motor to keep you safe.
I'd also mention out there's a large difference between 'safe' LO sites. Some offer convenient accommodation (wide-open approach, smooth surface, room for a long roll-out, aerotow retrievable, drive the trailer onto the field, beer nearby, etc). Others are more challenging but ultimately safe for the pilot. Challenging LO's include short fields, glider scuffing through low vegetation, bouncing across uneven surfaces, losing a gear door in a freshly plowed field, unexpected livestock, locked gates, no trailer access, needing you and your crew to attend a mine safety class before being allowed to retrieve your glider, etc.
I don't think these types of LO variations are particularly unique to AZ. It's part of our XC decision making process and risk assessment. It's important to always have a safe-for-the-pilot LO option. I make sure I do. Just like I did in the example I provided. But there are many defined safe LZ's in our area that you would definitely prefer not to land in. I'm very well acquainted with the distinctions and tomorrow, I'll be out on my 4th all-day land out survey expedition to document this season's current LZ conditions for a segment of our club's usual XC operating area. Having 100's of hang gliding XC 'land outs' with no prior LZ familiarization just doesn't cut it now that I'm flying gliders XC.
I did a bit of math using my recent example's igc log. I assumed that I turned a motor on at 5mi out (10mi into that final glide - the point which I clearly knew the highly undesirable mine tailing land out was a distinct possibility). With average sink rate changing from 8kts to 6kts - I make the field just below pattern altitude. While that's nice to see, it's a whole lot closer that I would have assumed and your point regarding limited glide improvement is a good one - thanks.

JJ

jfitch

March 10th 21, 02:01 AM

One thing a motorglider allows you to do is to select safer landout sites - not because you can motor away from a bad one, but because retreating towards a safer area, while still high, has less risk of inconvenience. A fair number of landouts in bad places can be attributed to wanting to get closer to home to have the retrieve be shorter, passing up better - but further away - choices. We had two landouts in a lake last year which probably had this as a component in the decision making. With the possibility of a motor start, retreating towards a nice safe paved runway does not have the same consequences for the rest of the evening.

When you are thinking about that final glide in sink, remember that pulling the motor out to start it will cost you a few hundred feet in altitude, even if it fails and you are able to put it away again. If it fails and you are unable to put it away, you've just given up about 1/2 your glider performance. On my glider the difference is 50:1 going to 20:1. The jets are a bit better and an FES better still, but there is still consequence, even if it is just a distraction from efficient flying. This is a real dilemma on a marginal final glide in a motorglider. I don't have a comfortable glide. Should I pull the motor out now while I still have enough altitude to try to deal with the consequences? If it doesn't start I will for sure not make it.. Should I have pulled it out 5 minutes ago? Too late now - will I regret, 5 minutes from now, not having pulled it out now? All these things run through your head.

On Tuesday, March 9, 2021 at 3:53:52 PM UTC-8, John Johnson wrote:
> On Tuesday, March 9, 2021 at 1:55:27 PM UTC-7, jfitch wrote:
> > If you are thinking of a motorglider as saving you from an unsafe landout, you are a Statistic - In -Waiting. What a motorglider does is save you the inconvenience of a safe landout and retrieve. If anything, it makes landouts more dangerous, as the pilot workload at a critical point increases (and this is an argument for electric, which typically takes less attention).. A motorglider does not increase your range over unlandable terrain, or improve your chances for a safe landout (not reliably, anyway). Your example of continuous 7 - 9 knot sink for example, would be turned into continuous 5 - 7 knot sink with a typical sustainer, and it would take the most powerful of self launch power plants to turn that into a climb (even if you are lucky enough to have the motor start). A motor is no substitute for intelligent decisions, and it is not a substitute for having an easy glide angle to a safe landing site at all times. I have two friends with motorgliders left in trees that can bear witness.
> >
> Agree with all your points and I don't think I've ever seen a motor related thread that doesn't preach the obvious: don't rely on your motor to keep you safe.
> I'd also mention out there's a large difference between 'safe' LO sites. Some offer convenient accommodation (wide-open approach, smooth surface, room for a long roll-out, aerotow retrievable, drive the trailer onto the field, beer nearby, etc). Others are more challenging but ultimately safe for the pilot. Challenging LO's include short fields, glider scuffing through low vegetation, bouncing across uneven surfaces, losing a gear door in a freshly plowed field, unexpected livestock, locked gates, no trailer access, needing you and your crew to attend a mine safety class before being allowed to retrieve your glider, etc.
> I don't think these types of LO variations are particularly unique to AZ. It's part of our XC decision making process and risk assessment. It's important to always have a safe-for-the-pilot LO option. I make sure I do. Just like I did in the example I provided. But there are many defined safe LZ's in our area that you would definitely prefer not to land in. I'm very well acquainted with the distinctions and tomorrow, I'll be out on my 4th all-day land out survey expedition to document this season's current LZ conditions for a segment of our club's usual XC operating area. Having 100's of hang gliding XC 'land outs' with no prior LZ familiarization just doesn't cut it now that I'm flying gliders XC.
> I did a bit of math using my recent example's igc log. I assumed that I turned a motor on at 5mi out (10mi into that final glide - the point which I clearly knew the highly undesirable mine tailing land out was a distinct possibility). With average sink rate changing from 8kts to 6kts - I make the field just below pattern altitude. While that's nice to see, it's a whole lot closer that I would have assumed and your point regarding limited glide improvement is a good one - thanks.
>
> JJ

John Johnson

March 10th 21, 02:46 AM

On Tuesday, March 9, 2021 at 7:01:56 PM UTC-7, jfitch wrote:
> This is a real dilemma on a marginal final glide in a motorglider. I don't have a comfortable glide. Should I pull the motor out now while I still have enough altitude to try to deal with the consequences? If it doesn't start I will for sure not make it. Should I have pulled it out 5 minutes ago? Too late now - will I regret, 5 minutes from now, not having pulled it out now? All these things run through your head.

Good points. I can see where a 'backup' motor sounds great on the surface, but in practice its whole 'nother set of complex decisions and uncertain risk tradeoffs. More so than I was considering.
Continuing to benefit from this thread - thanks.
JJ

John Galloway[_2_]

March 10th 21, 09:38 AM

On Wednesday, 10 March 2021 at 02:01:56 UTC, jfitch wrote:
> One thing a motorglider allows you to do is to select safer landout sites - not because you can motor away from a bad one, but because retreating towards a safer area, while still high, has less risk of inconvenience. A fair number of landouts in bad places can be attributed to wanting to get closer to home to have the retrieve be shorter, passing up better - but further away - choices. We had two landouts in a lake last year which probably had this as a component in the decision making. With the possibility of a motor start, retreating towards a nice safe paved runway does not have the same consequences for the rest of the evening.
>
> When you are thinking about that final glide in sink, remember that pulling the motor out to start it will cost you a few hundred feet in altitude, even if it fails and you are able to put it away again. If it fails and you are unable to put it away, you've just given up about 1/2 your glider performance. On my glider the difference is 50:1 going to 20:1. The jets are a bit better and an FES better still, but there is still consequence, even if it is just a distraction from efficient flying. This is a real dilemma on a marginal final glide in a motorglider. I don't have a comfortable glide. Should I pull the motor out now while I still have enough altitude to try to deal with the consequences? If it doesn't start I will for sure not make it. Should I have pulled it out 5 minutes ago? Too late now - will I regret, 5 minutes from now, not having pulled it out now? All these things run through your head.
> On Tuesday, March 9, 2021 at 3:53:52 PM UTC-8, John Johnson wrote:
> > On Tuesday, March 9, 2021 at 1:55:27 PM UTC-7, jfitch wrote:
> > > If you are thinking of a motorglider as saving you from an unsafe landout, you are a Statistic - In -Waiting. What a motorglider does is save you the inconvenience of a safe landout and retrieve. If anything, it makes landouts more dangerous, as the pilot workload at a critical point increases (and this is an argument for electric, which typically takes less attention). A motorglider does not increase your range over unlandable terrain, or improve your chances for a safe landout (not reliably, anyway). Your example of continuous 7 - 9 knot sink for example, would be turned into continuous 5 - 7 knot sink with a typical sustainer, and it would take the most powerful of self launch power plants to turn that into a climb (even if you are lucky enough to have the motor start). A motor is no substitute for intelligent decisions, and it is not a substitute for having an easy glide angle to a safe landing site at all times. I have two friends with motorgliders left in trees that can bear witness.
> > >
> > Agree with all your points and I don't think I've ever seen a motor related thread that doesn't preach the obvious: don't rely on your motor to keep you safe.
> > I'd also mention out there's a large difference between 'safe' LO sites.. Some offer convenient accommodation (wide-open approach, smooth surface, room for a long roll-out, aerotow retrievable, drive the trailer onto the field, beer nearby, etc). Others are more challenging but ultimately safe for the pilot. Challenging LO's include short fields, glider scuffing through low vegetation, bouncing across uneven surfaces, losing a gear door in a freshly plowed field, unexpected livestock, locked gates, no trailer access, needing you and your crew to attend a mine safety class before being allowed to retrieve your glider, etc.
> > I don't think these types of LO variations are particularly unique to AZ. It's part of our XC decision making process and risk assessment. It's important to always have a safe-for-the-pilot LO option. I make sure I do. Just like I did in the example I provided. But there are many defined safe LZ's in our area that you would definitely prefer not to land in. I'm very well acquainted with the distinctions and tomorrow, I'll be out on my 4th all-day land out survey expedition to document this season's current LZ conditions for a segment of our club's usual XC operating area. Having 100's of hang gliding XC 'land outs' with no prior LZ familiarization just doesn't cut it now that I'm flying gliders XC.
> > I did a bit of math using my recent example's igc log. I assumed that I turned a motor on at 5mi out (10mi into that final glide - the point which I clearly knew the highly undesirable mine tailing land out was a distinct possibility). With average sink rate changing from 8kts to 6kts - I make the field just below pattern altitude. While that's nice to see, it's a whole lot closer that I would have assumed and your point regarding limited glide improvement is a good one - thanks.
> >
> > JJ

A marginal final glide in a motor glider (FES perhaps excepted) is a final glide in a glider in my mind.

Tango Whisky

March 10th 21, 01:08 PM

Yep. There is a decision altitude below which the engine is no option anymore.

Le mercredi 10 mars 2021 Ã* 10:38:28 UTC+1, a Ã©critÂ*:
> On Wednesday, 10 March 2021 at 02:01:56 UTC, jfitch wrote:
> > > JJ
> A marginal final glide in a motor glider (FES perhaps excepted) is a final glide in a glider in my mind.

Jonathan St. Cloud

March 10th 21, 04:21 PM

What actions did you take to get out of the sustained sink? Having owned and flown pure gliders, sustainers, and motor gliders I can attest that an engine is not a substitute for xc skills. If you want a
sustainer, imagine flying the flights you have flown with half a load of water that you cannot dump. Every time the engine starts should be a surprise, because
if it doesn't start you now have effectively full open and locked airbrakes.. I fly an engined glider just like the engine is not going to start. Twice I have landed out without even attempting the engine as I have a hard deck
where below I will not be stupid.
Jon

On Tuesday, March 9, 2021 at 10:36:11 AM UTC-8, John Johnson wrote:
> Enjoying this thread. I'm a newbie - flying XC for about a year now. I definitely would like self-launch capability and just some 'modest' sustaining capacity left over. My land outs and close calls to-date could have all been mitigated by 10min (or less) of sustaining assist. If I fly so deep into marginal conditions that I need an hour of power to get home, I must have really made some bad decisions. Soaring conditions here in southern AZ are pretty great but land out options can be challenging. I see sustaining needs as more about dealing with localized exceptions and improving your land out choices. If I needed >1 launch or >10-15min flight time, I don't think the conditions were aligned for the XC flight I was looking for anyway.
>
> Example: I was recently surprised by continuous 7-9kt sink over a 15mi final glide. I started out with a 3200' agl arrival altitude cushion and watched it drop to <200ft as I soldiered home and left my last favorable LO options behind. I was stuck looking at an emergency bailout on a mine tailing that has generated a number of scary tales in my club. I was lucky to find some lift off a local feature just 2mi out and got enough altitude to make the field in good shape. 2-3min of powered sustaining flight would have made that a non-event.
>
> One launch and some modest assist capacity would be awesome and fit my primary goals:
> - independent launch capability
> - backup for the times I need a short boost to avoid a land out or help get me to a safer land out option
> - I'm ok with landing out on occasion if its safe and retrievable
> - Really prefer electric over ICE
>
> Seems like the current mast-mounted electric technology is just about there for my goals. It's now more about solution maturity, track record, and $$ as I watch how things shake out. I do, however, want hear about alternate use models and scenarios that could affect my decisions.
>
> JJ

Dan Marotta

March 10th 21, 04:24 PM

When considering outlanding options and engines, consider flying west
from Taos, NM:
,187744m/data=!3m1!1e3

Dan
5J

On 3/10/21 6:08 AM, Tango Whisky wrote:
> Yep. There is a decision altitude below which the engine is no option anymore.
>
> Le mercredi 10 mars 2021 Ã* 10:38:28 UTC+1, a Ã©critÂ*:
>> On Wednesday, 10 March 2021 at 02:01:56 UTC, jfitch wrote:
>>>> JJ
>> A marginal final glide in a motor glider (FES perhaps excepted) is a final glide in a glider in my mind.

waremark

March 11th 21, 12:42 AM

Someone said:

"Electric self-launchers seem particularly
well-suited to partnerships, with their easier use of the motor."

The contrary may be the case for electric gliders with removable batteries. At our airfield the electricity supply will not be adequate for the potential recharging requirements of more electric gliders. At the moment the only FES gliders at the club are individually owned, and the owners take the batteries home to charge them. The batteries of a syndicate owned glider would have to be charged on site - which will become a problem.

On a completely different point, I have been flying an ICE self-launcher for 14 years. I like to take off with sufficient fuel on board for a relight and a self-retrieve. I have rarely needed it, but if I didn't I would need to make road retrieve arrangements before cross country flights. I won't change to an electric glider until it has that sort of endurance - which is unlikely in my gliding lifetime.

Incidentally, twice in the 14 years I have landed in a field (safely, I am happy to say). The first time I initiated the start sequence at 1,000 foot on downwind, and the engine failed to start. The second time, I was on a marginal final glide, I took a clear decision to continue below a safe engine start height in the knowledge that there were safe fields on the way to the airfield, and when the final glide became too marginal I landed in a field without considering deploying the engine. Happily, I have never had to start the engine other than over a safe place to land.

Matthew Scutter

March 11th 21, 01:33 AM

On Thursday, March 11, 2021 at 10:42:32 AM UTC+10, waremark wrote:
> Someone said:
>
> "Electric self-launchers seem particularly
> well-suited to partnerships, with their easier use of the motor."
>
> The contrary may be the case for electric gliders with removable batteries. At our airfield the electricity supply will not be adequate for the potential recharging requirements of more electric gliders. At the moment the only FES gliders at the club are individually owned, and the owners take the batteries home to charge them. The batteries of a syndicate owned glider would have to be charged on site - which will become a problem.
>
> On a completely different point, I have been flying an ICE self-launcher for 14 years. I like to take off with sufficient fuel on board for a relight and a self-retrieve. I have rarely needed it, but if I didn't I would need to make road retrieve arrangements before cross country flights. I won't change to an electric glider until it has that sort of endurance - which is unlikely in my gliding lifetime.
>
> Incidentally, twice in the 14 years I have landed in a field (safely, I am happy to say). The first time I initiated the start sequence at 1,000 foot on downwind, and the engine failed to start. The second time, I was on a marginal final glide, I took a clear decision to continue below a safe engine start height in the knowledge that there were safe fields on the way to the airfield, and when the final glide became too marginal I landed in a field without considering deploying the engine. Happily, I have never had to start the engine other than over a safe place to land.

Is your airfield off-grid? How constrained is the capacity of your club's electricity connection that you wouldn't be able to handle charging gliders there? The FES chargers are 1200W, the Antares is similar. They seem to only charge at full current briefly and then start dropping down rapidly as the batteries approach full charge. Even with a single phase connection you should be fine for 12 gliders at max current simultaneously. I even charge my FES batteries off an inverter in my van (which has 2x135Ah Lithiums + 300W solar + 1000W inverter).

kinsell

March 11th 21, 03:49 AM

On 3/6/21 1:13 PM, Kenn Sebesta wrote:

> The genius of all this is that as battery tech improves the existing plane just gets better and better. When you're looking at your replacement pack 5-10 years down the road you'll automatically benefit from all the improvements and your new pack will either be cheaper, or it'll fly longer, or it'll be lighter. Maybe all three. Certainly never saw 100LL get cheaper, better, and lighter!
>

Well, ten years ago the FES folks came out with with their Gen 1
batteries featuring 2.1 kWhr of capacity. Now we're up to Gen 2,
featuring a walloping 2.1 kWhr. See how much improvement there's been?
They did manage to take the metal filings out of the packs, so yeah I
guess they did get a little lighter.

Wonder if Nadler has ripped the batteries out of his 15 year old wings
and put in super cells to make an Antares Turbo? I'm guessing not.

So do people buying a self launcher only want to do a 1K' launch? The
guy in Connecticut thought he'd dip into the "excess capacity" somebody
was talking about, and squeak back to the airport at rooftop level.
Unfortunately he found himself below rooftop level in no time flat.

Matthew Scutter

March 11th 21, 05:19 AM

On Thursday, March 11, 2021 at 1:49:45 PM UTC+10, kinsell wrote:
> On 3/6/21 1:13 PM, Kenn Sebesta wrote:
>
> > The genius of all this is that as battery tech improves the existing plane just gets better and better. When you're looking at your replacement pack 5-10 years down the road you'll automatically benefit from all the improvements and your new pack will either be cheaper, or it'll fly longer, or it'll be lighter. Maybe all three. Certainly never saw 100LL get cheaper, better, and lighter!
> >
>
> Well, ten years ago the FES folks came out with with their Gen 1
> batteries featuring 2.1 kWhr of capacity. Now we're up to Gen 2,
> featuring a walloping 2.1 kWhr. See how much improvement there's been?
> They did manage to take the metal filings out of the packs, so yeah I
> guess they did get a little lighter.
>
> Wonder if Nadler has ripped the batteries out of his 15 year old wings
> and put in super cells to make an Antares Turbo? I'm guessing not.
>
> So do people buying a self launcher only want to do a 1K' launch? The
> guy in Connecticut thought he'd dip into the "excess capacity" somebody
> was talking about, and squeak back to the airport at rooftop level.
> Unfortunately he found himself below rooftop level in no time flat.

They're onto GEN3 now:
The GEN3 53Ah / 5.5kWh packs have 32% more energy in a package 13% larger.
The GEN3 70Ah / 7.7kWh packs have 85% more energy in a package 25% larger.

waremark

March 11th 21, 07:56 PM

On Thursday, 11 March 2021 at 01:33:34 UTC, Matthew Scutter wrote:
> On Thursday, March 11, 2021 at 10:42:32 AM UTC+10, waremark wrote:
> > Someone said:
> >
> > "Electric self-launchers seem particularly
> > well-suited to partnerships, with their easier use of the motor."
> >
> > The contrary may be the case for electric gliders with removable batteries. At our airfield the electricity supply will not be adequate for the potential recharging requirements of more electric gliders. At the moment the only FES gliders at the club are individually owned, and the owners take the batteries home to charge them. The batteries of a syndicate owned glider would have to be charged on site - which will become a problem.
> >
> > On a completely different point, I have been flying an ICE self-launcher for 14 years. I like to take off with sufficient fuel on board for a relight and a self-retrieve. I have rarely needed it, but if I didn't I would need to make road retrieve arrangements before cross country flights. I won't change to an electric glider until it has that sort of endurance - which is unlikely in my gliding lifetime.
> >
> > Incidentally, twice in the 14 years I have landed in a field (safely, I am happy to say). The first time I initiated the start sequence at 1,000 foot on downwind, and the engine failed to start. The second time, I was on a marginal final glide, I took a clear decision to continue below a safe engine start height in the knowledge that there were safe fields on the way to the airfield, and when the final glide became too marginal I landed in a field without considering deploying the engine. Happily, I have never had to start the engine other than over a safe place to land.
> Is your airfield off-grid? How constrained is the capacity of your club's electricity connection that you wouldn't be able to handle charging gliders there? The FES chargers are 1200W, the Antares is similar. They seem to only charge at full current briefly and then start dropping down rapidly as the batteries approach full charge. Even with a single phase connection you should be fine for 12 gliders at max current simultaneously. I even charge my FES batteries off an inverter in my van (which has 2x135Ah Lithiums + 300W solar + 1000W inverter).

On grid - but of course we have a lot of draw for other purposes before people start charging gliders.

Eric Greenwell[_4_]

March 12th 21, 01:18 AM

waremark wrote on 3/10/2021 4:42 PM:
> On a completely different point, I have been flying an ICE self-launcher for 14 years. I like to take off with sufficient fuel on board for a relight and a self-retrieve.

How long a self-retrieve distance is the minimum acceptable to you?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric Greenwell[_4_]

March 12th 21, 03:33 AM

Matthew Scutter wrote on 3/10/2021 9:19 PM:
> On Thursday, March 11, 2021 at 1:49:45 PM UTC+10, kinsell wrote:
>> On 3/6/21 1:13 PM, Kenn Sebesta wrote:
>>
>>> The genius of all this is that as battery tech improves the existing plane just gets better and better. When you're looking at your replacement pack 5-10 years down the road you'll automatically benefit from all the improvements and your new pack will either be cheaper, or it'll fly longer, or it'll be lighter. Maybe all three. Certainly never saw 100LL get cheaper, better, and lighter!
>>>
>>
>> Well, ten years ago the FES folks came out with with their Gen 1
>> batteries featuring 2.1 kWhr of capacity. Now we're up to Gen 2,
>> featuring a walloping 2.1 kWhr. See how much improvement there's been?
>> They did manage to take the metal filings out of the packs, so yeah I
>> guess they did get a little lighter.
>>
>> Wonder if Nadler has ripped the batteries out of his 15 year old wings
>> and put in super cells to make an Antares Turbo? I'm guessing not.
>>
>> So do people buying a self launcher only want to do a 1K' launch? The
>> guy in Connecticut thought he'd dip into the "excess capacity" somebody
>> was talking about, and squeak back to the airport at rooftop level.
>> Unfortunately he found himself below rooftop level in no time flat.
>
> They're onto GEN3 now:
> The GEN3 53Ah / 5.5kWh packs have 32% more energy in a package 13% larger.
> The GEN3 70Ah / 7.7kWh packs have 85% more energy in a package 25% larger.
>
Our current situation reminds me of 25 years ago, when I got my ASH26E. Pilots with or wanting
self launchers were reminded that "real glider pilots" did not need motors to go soaring, and
it was essentially cheating to use one for records or contests. Now, motorgliders (at least gas
powered ones) are accepted and desired by those that don't have one. Nonetheless, the prejudice
and bias have not disappeared, but have shifted the focus to electric motorgliders and their
pilots. Those pilots are reminded that "real glider pilots" want the power and range that only
a gas powered glider can deliver, and will soon regret their foolishness if they stick with or
choose electric gliders.

I don't think it will take 15+ more years for electric gliders to be accepted and desired like
gas powered gliders are now. With FES and mast-mounted electrics available from all the major
manufacturers, I think this year is the "tipping point", and sales of electrics will "soon"
increase faster than the gas powered sales; unfortunately, I don't know of any good way to
track sales.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Ramy[_2_]

March 12th 21, 06:20 AM

One of the things that attracts me about FES is precisely the relatively shorter range, so you still depend largely on your soaring skills to make it back, while still able to self launch and only occasionally relight just enough to get that last 1000 feet climb when the day died a little too early....

Ramy

On Thursday, March 11, 2021 at 7:33:55 PM UTC-8, Eric Greenwell wrote:
> Matthew Scutter wrote on 3/10/2021 9:19 PM:
> > On Thursday, March 11, 2021 at 1:49:45 PM UTC+10, kinsell wrote:
> >> On 3/6/21 1:13 PM, Kenn Sebesta wrote:
> >>
> >>> The genius of all this is that as battery tech improves the existing plane just gets better and better. When you're looking at your replacement pack 5-10 years down the road you'll automatically benefit from all the improvements and your new pack will either be cheaper, or it'll fly longer, or it'll be lighter. Maybe all three. Certainly never saw 100LL get cheaper, better, and lighter!
> >>>
> >>
> >> Well, ten years ago the FES folks came out with with their Gen 1
> >> batteries featuring 2.1 kWhr of capacity. Now we're up to Gen 2,
> >> featuring a walloping 2.1 kWhr. See how much improvement there's been?
> >> They did manage to take the metal filings out of the packs, so yeah I
> >> guess they did get a little lighter.
> >>
> >> Wonder if Nadler has ripped the batteries out of his 15 year old wings
> >> and put in super cells to make an Antares Turbo? I'm guessing not.
> >>
> >> So do people buying a self launcher only want to do a 1K' launch? The
> >> guy in Connecticut thought he'd dip into the "excess capacity" somebody
> >> was talking about, and squeak back to the airport at rooftop level.
> >> Unfortunately he found himself below rooftop level in no time flat.
> >
> > They're onto GEN3 now:
> > The GEN3 53Ah / 5.5kWh packs have 32% more energy in a package 13% larger.
> > The GEN3 70Ah / 7.7kWh packs have 85% more energy in a package 25% larger.
> >
> Our current situation reminds me of 25 years ago, when I got my ASH26E. Pilots with or wanting
> self launchers were reminded that "real glider pilots" did not need motors to go soaring, and
> it was essentially cheating to use one for records or contests. Now, motorgliders (at least gas
> powered ones) are accepted and desired by those that don't have one. Nonetheless, the prejudice
> and bias have not disappeared, but have shifted the focus to electric motorgliders and their
> pilots. Those pilots are reminded that "real glider pilots" want the power and range that only
> a gas powered glider can deliver, and will soon regret their foolishness if they stick with or
> choose electric gliders.
>
> I don't think it will take 15+ more years for electric gliders to be accepted and desired like
> gas powered gliders are now. With FES and mast-mounted electrics available from all the major
> manufacturers, I think this year is the "tipping point", and sales of electrics will "soon"
> increase faster than the gas powered sales; unfortunately, I don't know of any good way to
> track sales.
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[email protected]

March 12th 21, 08:38 AM

On Friday, 12 March 2021 at 04:33:55 UTC+1, Eric Greenwell wrote:
>
> I don't think it will take 15+ more years for electric gliders to be accepted and desired like
> gas powered gliders are now. With FES and mast-mounted electrics available from all the major
> manufacturers, I think this year is the "tipping point", and sales of electrics will "soon"
> increase faster than the gas powered sales; unfortunately, I don't know of any good way to
> track sales.

Just one datapoint, Jonker in their latest newsletter reported the following about their electrical JS3 RES:
"The first 5 JS3 RES gliders are currently in production with another 30 planned for 2021."
If they plan to produce 35 electrical JS3s in 2021, I assume that will be most of their production of JS3s. They produced their 100th JS3 last year, 4 years after it was introduced, so up until then average production was around 25 per year.

Of course, they don't have any combustion engine self launch version of the JS3 to compare with, though the heavily delayed JS2 is about to enter production. Don't know any order numbers for that one.

Dan Marotta

March 12th 21, 06:30 PM

Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by
a distance of 350 nautical miles? That's what I'll be doing in June to
relocate the Stemme from Moriarty, NM to Rifle, CO. And it might use
half a tank of gas.

Of course, I'll only do it that way if soaring conditions don't support
gliding the whole way.

Dan
5J

On 3/11/21 6:18 PM, Eric Greenwell wrote:
>
>
> How long a self-retrieve distance is the minimum acceptable to you?
>

Eric Greenwell[_4_]

March 13th 21, 03:27 AM

Dan Marotta wrote on 3/12/2021 10:30 AM:
> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> nautical miles?* That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> Rifle, CO.* And it might use half a tank of gas.
>
> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
>
> Dan
> 5J
>
> On 3/11/21 6:18 PM, Eric Greenwell wrote:
>>
>>
>> How long a self-retrieve distance is the minimum acceptable to you?
>>
Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )

But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
enough retrieve distance, and some think 50 miles is plenty. These are the people that are
willing to drive from where they live to where they want to fly. I'm one of those people,
because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
in it.

March 13th 21, 07:55 PM

On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> Dan Marotta wrote on 3/12/2021 10:30 AM:
> > Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> > nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> > Rifle, CO. And it might use half a tank of gas.
> >
> > Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> >
> > Dan
> > 5J
> >
> > On 3/11/21 6:18 PM, Eric Greenwell wrote:
> >>
> >>
> >> How long a self-retrieve distance is the minimum acceptable to you?
> >>
> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
>
> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> willing to drive from where they live to where they want to fly. I'm one of those people,
> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> in it.

Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).

Tom

Eric Greenwell[_4_]

March 14th 21, 03:59 AM

2G wrote on 3/13/2021 11:55 AM:
> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
>> Dan Marotta wrote on 3/12/2021 10:30 AM:
>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
>>> Rifle, CO. And it might use half a tank of gas.
>>>
>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
>>>
>>> Dan
>>> 5J
>>>
>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
>>>>
>>>>
>>>> How long a self-retrieve distance is the minimum acceptable to you?
>>>>
>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
>>
>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
>> willing to drive from where they live to where they want to fly. I'm one of those people,
>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
>> in it.
>
> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).

According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.

How often have you had to motor home more than 90 sm?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

March 15th 21, 10:31 PM

On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
> 2G wrote on 3/13/2021 11:55 AM:
> > On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> >> Dan Marotta wrote on 3/12/2021 10:30 AM:
> >>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> >>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> >>> Rifle, CO. And it might use half a tank of gas.
> >>>
> >>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> >>>
> >>> Dan
> >>> 5J
> >>>
> >>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
> >>>>
> >>>>
> >>>> How long a self-retrieve distance is the minimum acceptable to you?
> >>>>
> >> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
> >>
> >> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
> >> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> >> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> >> willing to drive from where they live to where they want to fly. I'm one of those people,
> >> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> >> in it.
> >
> > Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
>
> How often have you had to motor home more than 90 sm?
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.

Tom

Eric Greenwell[_4_]

March 16th 21, 12:10 AM

2G wrote on 3/15/2021 3:31 PM:
> On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
>> 2G wrote on 3/13/2021 11:55 AM:
>>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
>>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
>>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
>>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
>>>>> Rifle, CO. And it might use half a tank of gas.
>>>>>
>>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
>>>>>
>>>>> Dan
>>>>> 5J
>>>>>
>>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
>>>>>>
>>>>>>
>>>>>> How long a self-retrieve distance is the minimum acceptable to you?
>>>>>>
>>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
>>>>
>>>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
>>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
>>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
>>>> willing to drive from where they live to where they want to fly. I'm one of those people,
>>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
>>>> in it.
>>>
>>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
>> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
>> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
>> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
>> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
>>
>> How often have you had to motor home more than 90 sm?
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.

The answer to the situation you propose (not enough range to get home) is a simple one: land at
the airport that makes for the shortest retrieve before the battery runs out, wait for the
towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
far apart; at Parowan, or home, as close as 20 miles.

The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
flight for the return would already have climbs that exceeded that.

Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
that experience when considering what glider is suitable for me. After all, I did write the
book on operating motorgliders :^)

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Matthew Scutter

March 16th 21, 12:30 AM

On Tuesday, March 16, 2021 at 10:10:51 AM UTC+10, Eric Greenwell wrote:
> 2G wrote on 3/15/2021 3:31 PM:
> > On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
> >> 2G wrote on 3/13/2021 11:55 AM:
> >>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> >>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
> >>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> >>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> >>>>> Rifle, CO. And it might use half a tank of gas.
> >>>>>
> >>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> >>>>>
> >>>>> Dan
> >>>>> 5J
> >>>>>
> >>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
> >>>>>>
> >>>>>>
> >>>>>> How long a self-retrieve distance is the minimum acceptable to you?
> >>>>>>
> >>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
> >>>>
> >>>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
> >>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> >>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> >>>> willing to drive from where they live to where they want to fly. I'm one of those people,
> >>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> >>>> in it.
> >>>
> >>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
> >> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
> >> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
> >> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
> >> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
> >>
> >> How often have you had to motor home more than 90 sm?
> >> --
> >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >> - "A Guide to Self-Launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
> The answer to the situation you propose (not enough range to get home) is a simple one: land at
> the airport that makes for the shortest retrieve before the battery runs out, wait for the
> towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
> far apart; at Parowan, or home, as close as 20 miles.
>
> The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
> flight for the return would already have climbs that exceeded that.
>
> Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
> motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
> that experience when considering what glider is suitable for me. After all, I did write the
> book on operating motorgliders :^)
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Or recharge, then fly home the next day? I take a charger with me in my landout kit.

jfitch

March 16th 21, 02:08 AM

Most of the landout sites 60+ miles out of Ely, better bring a generator too....
On Monday, March 15, 2021 at 5:30:50 PM UTC-7, Matthew Scutter wrote:
> On Tuesday, March 16, 2021 at 10:10:51 AM UTC+10, Eric Greenwell wrote:
> > 2G wrote on 3/15/2021 3:31 PM:
> > > On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
> > >> 2G wrote on 3/13/2021 11:55 AM:
> > >>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> > >>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
> > >>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> > >>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> > >>>>> Rifle, CO. And it might use half a tank of gas.
> > >>>>>
> > >>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> > >>>>>
> > >>>>> Dan
> > >>>>> 5J
> > >>>>>
> > >>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
> > >>>>>>
> > >>>>>>
> > >>>>>> How long a self-retrieve distance is the minimum acceptable to you?
> > >>>>>>
> > >>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
> > >>>>
> > >>>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
> > >>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> > >>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> > >>>> willing to drive from where they live to where they want to fly. I'm one of those people,
> > >>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> > >>>> in it.
> > >>>
> > >>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
> > >> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
> > >> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
> > >> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
> > >> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
> > >>
> > >> How often have you had to motor home more than 90 sm?
> > >> --
> > >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > >> - "A Guide to Self-Launching Sailplane Operation"
> > >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > >
> > > Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
> > The answer to the situation you propose (not enough range to get home) is a simple one: land at
> > the airport that makes for the shortest retrieve before the battery runs out, wait for the
> > towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
> > far apart; at Parowan, or home, as close as 20 miles.
> >
> > The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
> > flight for the return would already have climbs that exceeded that.
> >
> > Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
> > motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
> > that experience when considering what glider is suitable for me. After all, I did write the
> > book on operating motorgliders :^)
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> Or recharge, then fly home the next day? I take a charger with me in my landout kit.

March 16th 21, 05:59 AM

On Monday, March 15, 2021 at 5:10:51 PM UTC-7, Eric Greenwell wrote:
> 2G wrote on 3/15/2021 3:31 PM:
> > On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
> >> 2G wrote on 3/13/2021 11:55 AM:
> >>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> >>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
> >>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> >>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> >>>>> Rifle, CO. And it might use half a tank of gas.
> >>>>>
> >>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> >>>>>
> >>>>> Dan
> >>>>> 5J
> >>>>>
> >>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
> >>>>>>
> >>>>>>
> >>>>>> How long a self-retrieve distance is the minimum acceptable to you?
> >>>>>>
> >>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
> >>>>
> >>>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
> >>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> >>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> >>>> willing to drive from where they live to where they want to fly. I'm one of those people,
> >>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> >>>> in it.
> >>>
> >>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
> >> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
> >> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
> >> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
> >> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
> >>
> >> How often have you had to motor home more than 90 sm?
> >> --
> >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >> - "A Guide to Self-Launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
> The answer to the situation you propose (not enough range to get home) is a simple one: land at
> the airport that makes for the shortest retrieve before the battery runs out, wait for the
> towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
> far apart; at Parowan, or home, as close as 20 miles.
>
> The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
> flight for the return would already have climbs that exceeded that.
>
> Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
> motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
> that experience when considering what glider is suitable for me. After all, I did write the
> book on operating motorgliders :^)
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

The case I cited the pilot did not come remotely close to making it to an airport: he found a small field that was landable. Retrieve was by 4WD and he got back to Ely at 2am. I considered that fortunate as one of the retrieves I went on the pilot didn't get back until more than a day later. That was the retrieve from hell which included dealing with a thunderstorm.
No, there is no way I would consider flying the GP15 out of Ely and I, too, have in excess of 4,000 hr of cross country glider time.

Tom

Eric Greenwell[_4_]

March 16th 21, 12:57 PM

2G wrote on 3/15/2021 10:59 PM:
> On Monday, March 15, 2021 at 5:10:51 PM UTC-7, Eric Greenwell wrote:
>> 2G wrote on 3/15/2021 3:31 PM:
>>> On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
>>>> 2G wrote on 3/13/2021 11:55 AM:
>>>>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
>>>>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
>>>>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
>>>>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
>>>>>>> Rifle, CO. And it might use half a tank of gas.
>>>>>>>
>>>>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
>>>>>>>
>>>>>>> Dan
>>>>>>> 5J
>>>>>>>
>>>>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> How long a self-retrieve distance is the minimum acceptable to you?
>>>>>>>>
>>>>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
>>>>>>
>>>>>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
>>>>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
>>>>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
>>>>>> willing to drive from where they live to where they want to fly. I'm one of those people,
>>>>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
>>>>>> in it.
>>>>>
>>>>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
>>>> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
>>>> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
>>>> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
>>>> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
>>>>
>>>> How often have you had to motor home more than 90 sm?
>>>> --
>>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>>>> - "A Guide to Self-Launching Sailplane Operation"
>>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>
>>> Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
>> The answer to the situation you propose (not enough range to get home) is a simple one: land at
>> the airport that makes for the shortest retrieve before the battery runs out, wait for the
>> towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
>> far apart; at Parowan, or home, as close as 20 miles.
>>
>> The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
>> flight for the return would already have climbs that exceeded that.
>>
>> Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
>> motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
>> that experience when considering what glider is suitable for me. After all, I did write the
>> book on operating motorgliders :^)
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> The case I cited the pilot did not come remotely close to making it to an airport: he found a small field that was landable. Retrieve was by 4WD and he got back to Ely at 2am. I considered that fortunate as one of the retrieves I went on the pilot didn't get back until more than a day later. That was the retrieve from hell which included dealing with a thunderstorm.
> No, there is no way I would consider flying the GP15 out of Ely and I, too, have in excess of 4,000 hr of cross country glider time.
>

The Ely type of area is the major reason I chose the 8.4kWh battery for my GP15, instead of the
4.7kWh battery, as it doubles the launch+retrieve distance. The 4.7 kWh battery is more
attractive in areas with more airports, as it allows a lower minimum wing loading, a higher
wing loading with only water ballast, and is $5000 cheaper. But many pilots choose to fly in
Ely conditions with 15M gliders with ZERO self-retrieve distance, and are clever enough to
avoid retrieves from hell. I have good reason to believe I can do the same with "only" 90 miles
of retrieve distance ;^)

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric Greenwell[_4_]

March 16th 21, 01:09 PM

Matthew Scutter wrote on 3/15/2021 5:30 PM:
> On Tuesday, March 16, 2021 at 10:10:51 AM UTC+10, Eric Greenwell wrote:
.....
>>
>> Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
>> motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
>> that experience when considering what glider is suitable for me. After all, I did write the
>> book on operating motorgliders :^)
>> --

> Or recharge, then fly home the next day? I take a charger with me in my landout kit.

I'm hoping that will be practical in the GP15. Overnight, even a small 500 watt charger would
be enough to add 50 self-retrieve miles to whatever charge was in the battery upon landing.
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Craig Reinholt

March 16th 21, 02:57 PM

One issue not discussed is the duration / altitude of the launch. At Ely, and other sites (Williams is one), the launch may run well over 20 minutes and altitude gain over 3000 feet hunting for lift. The numbers supplied by the manufacturers are for a 1500' gain under 10 minutes. That difference will put a severe dent on the retrieve distances.
Craig

Eric Greenwell[_4_]

March 16th 21, 06:05 PM

Craig Reinholt wrote on 3/16/2021 7:57 AM:
> One issue not discussed is the duration / altitude of the launch. At Ely, and other sites (Williams is one), the launch may run well over 20 minutes and altitude gain over 3000 feet hunting for lift. The numbers supplied by the manufacturers are for a 1500' gain under 10 minutes. That difference will put a severe dent on the retrieve distances.
> Craig
>
That hasn't been my experience at Ely, where a 2000' launch has almost always done the job, but
maybe I'm just lucky :^) Williams is a special case, and some FES will undoubtedly have to
take tows just to get to the soaring. It shouldn't be a problem for electrics with 50+ mile
range. Note that "the numbers" vary greatly between electric gliders, with some older FES
gliders having very limited climbs, and the newer mast-mounted motor systems by Schleicher,
Jonkers, and others offering 9,000'-13,000' climbs.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

kinsell

March 16th 21, 06:39 PM

On 3/16/21 12:05 PM, Eric Greenwell wrote:
> Craig Reinholt wrote on 3/16/2021 7:57 AM:
>> One issue not discussed is the duration / altitude of the launch. At
>> Ely, and other sites (Williams is one), the launch may run well over
>> 20 minutes and altitude gain over 3000 feet hunting for lift. The
>> numbers supplied by the manufacturers are for a 1500' gain under 10
>> minutes. That difference will put a severe dent on the retrieve
>> distances.
>> Craig
>>
> That hasn't been my experience at Ely, where a 2000' launch has almost
> always done the job, but maybe I'm just lucky :^)Â* Williams is a special
> case, and some FES will undoubtedly have to take tows just to get to the
> soaring. It shouldn't be a problem for electrics with 50+ mile range.
> Note that "the numbers" vary greatly between electric gliders, with some
> older FES gliders having very limited climbs, and the newer mast-mounted
> motor systems by Schleicher, Jonkers, and others offering 9,000'-13,000'
> climbs.
>

Well the Antares was supposed to have 10K feet climb capability, but in
reality it was a whole lot less. That shows the danger of comparing
real life performance of existing products with spec sheets of future
products. Don't suppose you went to Poland to verify the performance
numbers?

Mark Mocho

March 16th 21, 06:44 PM

Don't suppose you went to Poland to verify the performance
numbers?

Are there actually any GP-15 gliders in the hands of private owners? Or are they still on some imaginary delivery schedule? The only one I know of that was in the US was sent back for "upgrades." Don't know if it actually flew before going "home."

March 16th 21, 07:46 PM

On Tuesday, March 16, 2021 at 5:57:05 AM UTC-7, Eric Greenwell wrote:
> 2G wrote on 3/15/2021 10:59 PM:
> > On Monday, March 15, 2021 at 5:10:51 PM UTC-7, Eric Greenwell wrote:
> >> 2G wrote on 3/15/2021 3:31 PM:
> >>> On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
> >>>> 2G wrote on 3/13/2021 11:55 AM:
> >>>>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> >>>>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
> >>>>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> >>>>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> >>>>>>> Rifle, CO. And it might use half a tank of gas.
> >>>>>>>
> >>>>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> >>>>>>>
> >>>>>>> Dan
> >>>>>>> 5J
> >>>>>>>
> >>>>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> How long a self-retrieve distance is the minimum acceptable to you?
> >>>>>>>>
> >>>>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
> >>>>>>
> >>>>>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
> >>>>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> >>>>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> >>>>>> willing to drive from where they live to where they want to fly. I'm one of those people,
> >>>>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> >>>>>> in it.
> >>>>>
> >>>>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
> >>>> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
> >>>> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
> >>>> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
> >>>> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
> >>>>
> >>>> How often have you had to motor home more than 90 sm?
> >>>> --
> >>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >>>> - "A Guide to Self-Launching Sailplane Operation"
> >>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >>>
> >>> Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
> >> The answer to the situation you propose (not enough range to get home) is a simple one: land at
> >> the airport that makes for the shortest retrieve before the battery runs out, wait for the
> >> towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
> >> far apart; at Parowan, or home, as close as 20 miles.
> >>
> >> The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
> >> flight for the return would already have climbs that exceeded that.
> >>
> >> Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
> >> motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
> >> that experience when considering what glider is suitable for me. After all, I did write the
> >> book on operating motorgliders :^)
> >> --
> >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >> - "A Guide to Self-Launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > The case I cited the pilot did not come remotely close to making it to an airport: he found a small field that was landable. Retrieve was by 4WD and he got back to Ely at 2am. I considered that fortunate as one of the retrieves I went on the pilot didn't get back until more than a day later. That was the retrieve from hell which included dealing with a thunderstorm.
> > No, there is no way I would consider flying the GP15 out of Ely and I, too, have in excess of 4,000 hr of cross country glider time.
> >
> The Ely type of area is the major reason I chose the 8.4kWh battery for my GP15, instead of the
> 4.7kWh battery, as it doubles the launch+retrieve distance. The 4.7 kWh battery is more
> attractive in areas with more airports, as it allows a lower minimum wing loading, a higher
> wing loading with only water ballast, and is $5000 cheaper. But many pilots choose to fly in
> Ely conditions with 15M gliders with ZERO self-retrieve distance, and are clever enough to
> avoid retrieves from hell. I have good reason to believe I can do the same with "only" 90 miles
> of retrieve distance ;^)
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

I was stating what I would and would not do - you, of course, have to make your own decisions. Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it. I see it done routinely. But I won't be one of them. It also should be noted that they are flying high performance gliders (such as the ASG29) that are heavily ballasted; the GP15 is not in this category. The glider should be able to make a 20 nm glide using no more than 3,000 ft into a headwind. This is what it takes to cross valleys in Nevada and still be above the mountains on the other side with a comfortable margin.

Tom

Eric Greenwell[_4_]

March 16th 21, 07:49 PM

kinsell wrote on 3/16/2021 11:39 AM:
> On 3/16/21 12:05 PM, Eric Greenwell wrote:
>> Craig Reinholt wrote on 3/16/2021 7:57 AM:
>>> One issue not discussed is the duration / altitude of the launch. At Ely, and other sites
>>> (Williams is one), the launch may run well over 20 minutes and altitude gain over 3000 feet
>>> hunting for lift. The numbers supplied by the manufacturers are for a 1500' gain under 10
>>> minutes. That difference will put a severe dent on the retrieve distances.
>>> Craig
>>>
>> That hasn't been my experience at Ely, where a 2000' launch has almost always done the job,
>> but maybe I'm just lucky :^)* Williams is a special case, and some FES will undoubtedly have
>> to take tows just to get to the soaring. It shouldn't be a problem for electrics with 50+
>> mile range. Note that "the numbers" vary greatly between electric gliders, with some older
>> FES gliders having very limited climbs, and the newer mast-mounted motor systems by
>> Schleicher, Jonkers, and others offering 9,000'-13,000' climbs.
>>
>
> Well the Antares was supposed to have 10K feet climb capability, but in reality it was a whole
> lot less.* That shows the danger of* comparing real life performance of existing products with
> spec sheets of future products.* Don't suppose you went to Poland to verify the performance
> numbers?

A whole lot of experience and development has been gained since the Antares debut 18 years ago,
so I'm willing to accept the current claims by Schleicher, Schmepp-Hirth, and Jonkers. We don't
have flight reports for production GP15 gliders, but the power performance numbers on the spec
sheets are conservative when compared to other manufacturers' claims, so I am also willing to
accept GP's numbers as being close to reality.

I did not go to Poland, but dealer (Tom Holloran) did go to Poland and fly a GP15. Apparently,
he thought it was a very good glider, as he became the dealer, and one of the first few will be
his glider.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric Greenwell[_4_]

March 16th 21, 08:03 PM

Mark Mocho wrote on 3/16/2021 11:44 AM:
> Don't suppose you went to Poland to verify the performance
> numbers?
>
> Are there actually any GP-15 gliders in the hands of private owners? Or are they still on some imaginary delivery schedule? The only one I know of that was in the US was sent back for "upgrades." Don't know if it actually flew before going "home."
>
No GP15 gliders are in the hands of owners. The February factory report indicated the first two
GP15s might ship in late March, but no March report so far. The one at the convention has been
sold, and is on it's way to Poland for updates that will bring it close to current production
specifications.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric Greenwell[_4_]

March 16th 21, 08:35 PM

2G wrote on 3/16/2021 12:46 PM:
> On Tuesday, March 16, 2021 at 5:57:05 AM UTC-7, Eric Greenwell wrote:
>> 2G wrote on 3/15/2021 10:59 PM:
>...
>>>>>>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
>>>>>> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
>>>>>> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
>>>>>> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
>>>>>> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
>>>>>>
>>>>>> How often have you had to motor home more than 90 sm?
>>>>>> --
>>>>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>>>>>> - "A Guide to Self-Launching Sailplane Operation"
>>>>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>>>
>>>>> Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
>>>> The answer to the situation you propose (not enough range to get home) is a simple one: land at
>>>> the airport that makes for the shortest retrieve before the battery runs out, wait for the
>>>> towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
>>>> far apart; at Parowan, or home, as close as 20 miles.
>>>>
>>>> The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
>>>> flight for the return would already have climbs that exceeded that.
>>>>
>>>> Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
>>>> motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
>>>> that experience when considering what glider is suitable for me. After all, I did write the
>>>> book on operating motorgliders :^)
>>>> --
>>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>>>> - "A Guide to Self-Launching Sailplane Operation"
>>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>
>>> The case I cited the pilot did not come remotely close to making it to an airport: he found a small field that was landable. Retrieve was by 4WD and he got back to Ely at 2am. I considered that fortunate as one of the retrieves I went on the pilot didn't get back until more than a day later. That was the retrieve from hell which included dealing with a thunderstorm.
>>> No, there is no way I would consider flying the GP15 out of Ely and I, too, have in excess of 4,000 hr of cross country glider time.
>>>
>> The Ely type of area is the major reason I chose the 8.4kWh battery for my GP15, instead of the
>> 4.7kWh battery, as it doubles the launch+retrieve distance. The 4.7 kWh battery is more
>> attractive in areas with more airports, as it allows a lower minimum wing loading, a higher
>> wing loading with only water ballast, and is $5000 cheaper. But many pilots choose to fly in
>> Ely conditions with 15M gliders with ZERO self-retrieve distance, and are clever enough to
>> avoid retrieves from hell. I have good reason to believe I can do the same with "only" 90 miles
>> of retrieve distance ;^)
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> I was stating what I would and would not do - you, of course, have to make your own decisions. Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it. I see it done routinely. But I won't be one of them. It also should be noted that they are flying high performance gliders (such as the ASG29) that are heavily ballasted; the GP15 is not in this category. The glider should be able to make a 20 nm glide using no more than 3,000 ft into a headwind. This is what it takes to cross valleys in Nevada and still be above the mountains on the other side with a comfortable margin.

The GP15 has a maximum wing loading of 13.75 lb/ft2, three pounds more than, say, the 10.8
lb/ft2 of an ASH31Mi :^)

More likely, I will be flying it at 11 lb/ft2, which is 2.5 lb/ft2 higher than the ASH26E I
usually fly at Ely. And, since the GP15 L/D is almost identical to my ASH26E, I am sure I will
be even more comfortable than I am now.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

jfitch

March 16th 21, 09:18 PM

That makes it sound like you are depending on the engine to get you out of bad situations. Not a good idea in an electric or ICE. On the other hand people have been flying from Ely for decades without engines, so a working one really isn't necessary - just convenient. I suspect Eric will not have a problem.
On Tuesday, March 16, 2021 at 12:46:10 PM UTC-7, 2G wrote:
> On Tuesday, March 16, 2021 at 5:57:05 AM UTC-7, Eric Greenwell wrote:
> > 2G wrote on 3/15/2021 10:59 PM:
> > > On Monday, March 15, 2021 at 5:10:51 PM UTC-7, Eric Greenwell wrote:
> > >> 2G wrote on 3/15/2021 3:31 PM:
> > >>> On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
> > >>>> 2G wrote on 3/13/2021 11:55 AM:
> > >>>>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> > >>>>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
> > >>>>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> > >>>>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> > >>>>>>> Rifle, CO. And it might use half a tank of gas.
> > >>>>>>>
> > >>>>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> > >>>>>>>
> > >>>>>>> Dan
> > >>>>>>> 5J
> > >>>>>>>
> > >>>>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
> > >>>>>>>>
> > >>>>>>>>
> > >>>>>>>> How long a self-retrieve distance is the minimum acceptable to you?
> > >>>>>>>>
> > >>>>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
> > >>>>>>
> > >>>>>> But, I'm still interested in Waremark's far smaller requirements.. So far, the majority of the
> > >>>>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> > >>>>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> > >>>>>> willing to drive from where they live to where they want to fly. I'm one of those people,
> > >>>>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> > >>>>>> in it.
> > >>>>>
> > >>>>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
> > >>>> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
> > >>>> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
> > >>>> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
> > >>>> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
> > >>>>
> > >>>> How often have you had to motor home more than 90 sm?
> > >>>> --
> > >>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > >>>> - "A Guide to Self-Launching Sailplane Operation"
> > >>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > >>>
> > >>> Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
> > >> The answer to the situation you propose (not enough range to get home) is a simple one: land at
> > >> the airport that makes for the shortest retrieve before the battery runs out, wait for the
> > >> towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
> > >> far apart; at Parowan, or home, as close as 20 miles.
> > >>
> > >> The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
> > >> flight for the return would already have climbs that exceeded that.
> > >>
> > >> Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
> > >> motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
> > >> that experience when considering what glider is suitable for me. After all, I did write the
> > >> book on operating motorgliders :^)
> > >> --
> > >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > >> - "A Guide to Self-Launching Sailplane Operation"
> > >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > >
> > > The case I cited the pilot did not come remotely close to making it to an airport: he found a small field that was landable. Retrieve was by 4WD and he got back to Ely at 2am. I considered that fortunate as one of the retrieves I went on the pilot didn't get back until more than a day later. That was the retrieve from hell which included dealing with a thunderstorm.
> > > No, there is no way I would consider flying the GP15 out of Ely and I, too, have in excess of 4,000 hr of cross country glider time.
> > >
> > The Ely type of area is the major reason I chose the 8.4kWh battery for my GP15, instead of the
> > 4.7kWh battery, as it doubles the launch+retrieve distance. The 4.7 kWh battery is more
> > attractive in areas with more airports, as it allows a lower minimum wing loading, a higher
> > wing loading with only water ballast, and is $5000 cheaper. But many pilots choose to fly in
> > Ely conditions with 15M gliders with ZERO self-retrieve distance, and are clever enough to
> > avoid retrieves from hell. I have good reason to believe I can do the same with "only" 90 miles
> > of retrieve distance ;^)
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> I was stating what I would and would not do - you, of course, have to make your own decisions. Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it. I see it done routinely. But I won't be one of them. It also should be noted that they are flying high performance gliders (such as the ASG29) that are heavily ballasted; the GP15 is not in this category. The glider should be able to make a 20 nm glide using no more than 3,000 ft into a headwind. This is what it takes to cross valleys in Nevada and still be above the mountains on the other side with a comfortable margin.
>
> Tom

Ramy[_2_]

March 16th 21, 09:40 PM

Tom, Some of us fly from Ely for 20 years without any motor...
2 landouts in 20 years, none resulted in retrieve from hell. I am still planning to fly there with no motor.
Just sayin...
I hope I didnâ€™t jinx it...

Ramy

On Monday, March 15, 2021 at 10:59:53 PM UTC-7, 2G wrote:
> On Monday, March 15, 2021 at 5:10:51 PM UTC-7, Eric Greenwell wrote:
> > 2G wrote on 3/15/2021 3:31 PM:
> > > On Saturday, March 13, 2021 at 7:59:59 PM UTC-8, Eric Greenwell wrote:
> > >> 2G wrote on 3/13/2021 11:55 AM:
> > >>> On Friday, March 12, 2021 at 7:27:24 PM UTC-8, Eric Greenwell wrote:
> > >>>> Dan Marotta wrote on 3/12/2021 10:30 AM:
> > >>>>> Hows a self launch starting at 6,200' MSL up to 18,000' MSL followed by a distance of 350
> > >>>>> nautical miles? That's what I'll be doing in June to relocate the Stemme from Moriarty, NM to
> > >>>>> Rifle, CO. And it might use half a tank of gas.
> > >>>>>
> > >>>>> Of course, I'll only do it that way if soaring conditions don't support gliding the whole way.
> > >>>>>
> > >>>>> Dan
> > >>>>> 5J
> > >>>>>
> > >>>>> On 3/11/21 6:18 PM, Eric Greenwell wrote:
> > >>>>>>
> > >>>>>>
> > >>>>>> How long a self-retrieve distance is the minimum acceptable to you?
> > >>>>>>
> > >>>> Ok, you are not a current candidate for an electric motorglider (I knew that already :^) )
> > >>>>
> > >>>> But, I'm still interested in Waremark's far smaller requirements. So far, the majority of the
> > >>>> pilots I've talked to that are considering moving to an electric self-launcher think 100 sm is
> > >>>> enough retrieve distance, and some think 50 miles is plenty. These are the people that are
> > >>>> willing to drive from where they live to where they want to fly. I'm one of those people,
> > >>>> because my wife and I like to travel in a motorhome with her sewing projects and sewing machine
> > >>>> in it.
> > >>>
> > >>> Those must be flat-landers that don't have to clear even taller hills, let alone mountains. Your self-retrieve "distance" vanishes the moment you have to climb to clear an obstacle. Also, the electric self-launchers like the GP15 don't specify the retrieve distance when launching at MTOW. Think of it as getting you to a safe out-landing field which is how one pilot did at Ely last summer (and he took tows).
> > >> According to figures I have for the GP15, launching to 2600' agl at 8.5lb/ft2 uses about 20% of
> > >> the available energy (big battery); launching at 12 lb/ft2 would use about 28%. So, max
> > >> retrieve range would decrease comparably from 93 sm to 84 sm. Catch a thermal sooner, stop the
> > >> motor at 2000' agl, and it'd use 22%, so wold get 90 sm with the 12 lb/ft2 launch.
> > >>
> > >> How often have you had to motor home more than 90 sm?
> > >> --
> > >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > >> - "A Guide to Self-Launching Sailplane Operation"
> > >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> > >
> > > Just a few times, but I wasn't flying a 15M glider, either. In two seasons of flying the 31Mi I have only done one precautionary 5 mile "retrieve" only because I didn't want to do a marginal glide. Again, you ignore having to climb over obstacles. What would happen if you were 70 sm out AND had to climb 3,000 ft? And, then, throw in a 20 kt headwind. I probably wouldn't even consider flying the GP15 at Ely.
> > The answer to the situation you propose (not enough range to get home) is a simple one: land at
> > the airport that makes for the shortest retrieve before the battery runs out, wait for the
> > towplane (or trailer) to come, go home. At Ely, that would be 60+ miles, since airports are so
> > far apart; at Parowan, or home, as close as 20 miles.
> >
> > The main difficulty would likely be the wind, not the 3000' climb, as using a climb/glide
> > flight for the return would already have climbs that exceeded that.
> >
> > Anyway, relax a bit, don't let your range anxiety cloud your thinking. I have 4000+ hours in a
> > motorgliders, much of it in places with mountains - as you know. I assure you, I have used all
> > that experience when considering what glider is suitable for me. After all, I did write the
> > book on operating motorgliders :^)
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> The case I cited the pilot did not come remotely close to making it to an airport: he found a small field that was landable. Retrieve was by 4WD and he got back to Ely at 2am. I considered that fortunate as one of the retrieves I went on the pilot didn't get back until more than a day later. That was the retrieve from hell which included dealing with a thunderstorm.
> No, there is no way I would consider flying the GP15 out of Ely and I, too, have in excess of 4,000 hr of cross country glider time.
>
> Tom

Eric Greenwell[_4_]

March 16th 21, 10:48 PM

2G wrote on 3/16/2021 12:46 PM:
> Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it.

I forgot to respond to the "non-motorized" portion of your remarks. Perhaps you will be
surprised (or at least interested) to learn the GP15 climb rate from the runway on a typical
flying day at Ely will be nearly double the climb rate of my ASH26E. A major reason is the
electric motor still has the same power at 9000' DA, while the carbureted Wankel has lost about
18%. The better climb on takeoff in high density altitudes was an important factor in my
choice. It's not important at Ely, but it is at Parowan, and a few other places I've flown (or
wanted to fly but decided it was marginal).

Now, I realize you think 90 miles of self-retrieve is the same as zero miles, but that view is
not shared by every "pure" glider pilot out there!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Dave Nadler

March 17th 21, 12:56 AM

On 3/16/2021 3:49 PM, Eric Greenwell wrote:
> ...I'm willing to accept the current claims by Schleicher, Schmepp-Hirth, and Jonkers.
> ... I am also willing to accept GP's numbers as being close to reality.

Based on what - magical thinking?
Because others claim something similar but also have not demonstrated?

> I did not go to Poland, but dealer (Tom Holloran) did go to Poland and
> fly a GP15. Apparently, he thought it was a very good glider, as he
> became the dealer, and one of the first few will be his glider.

Been there, done that. OK it was Germany not Poland ;-)

March 17th 21, 05:17 AM

On Tuesday, March 16, 2021 at 3:48:54 PM UTC-7, Eric Greenwell wrote:
> 2G wrote on 3/16/2021 12:46 PM:
> > Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it.
> I forgot to respond to the "non-motorized" portion of your remarks. Perhaps you will be
> surprised (or at least interested) to learn the GP15 climb rate from the runway on a typical
> flying day at Ely will be nearly double the climb rate of my ASH26E. A major reason is the
> electric motor still has the same power at 9000' DA, while the carbureted Wankel has lost about
> 18%. The better climb on takeoff in high density altitudes was an important factor in my
> choice. It's not important at Ely, but it is at Parowan, and a few other places I've flown (or
> wanted to fly but decided it was marginal).
>
> Now, I realize you think 90 miles of self-retrieve is the same as zero miles, but that view is
> not shared by every "pure" glider pilot out there!
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Where do you get 90 miles? GP's website doesn't list it. Their numbers are dry - if you can trust them (nobody's verified them and they may be estimated for all you know). The self-retrieve distance they list for the B battery is 100km (63 miles) with a 800m launch with no ballast. Now add ballast, add an 3,000 ft obstacle and a 20kt headwind (all realistic conditions at Ely) and refigure what the hypothetical retrieve distance is, if any.

Tom

Eric Greenwell[_4_]

March 17th 21, 12:59 PM

2G wrote on 3/16/2021 10:17 PM:
> On Tuesday, March 16, 2021 at 3:48:54 PM UTC-7, Eric Greenwell wrote:
>> 2G wrote on 3/16/2021 12:46 PM:
>>> Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it.
>> I forgot to respond to the "non-motorized" portion of your remarks. Perhaps you will be
>> surprised (or at least interested) to learn the GP15 climb rate from the runway on a typical
>> flying day at Ely will be nearly double the climb rate of my ASH26E. A major reason is the
>> electric motor still has the same power at 9000' DA, while the carbureted Wankel has lost about
>> 18%. The better climb on takeoff in high density altitudes was an important factor in my
>> choice. It's not important at Ely, but it is at Parowan, and a few other places I've flown (or
>> wanted to fly but decided it was marginal).
>>
>> Now, I realize you think 90 miles of self-retrieve is the same as zero miles, but that view is
>> not shared by every "pure" glider pilot out there!
>> --
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>> - "A Guide to Self-Launching Sailplane Operation"
>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> Where do you get 90 miles? GP's website doesn't list it. Their numbers are dry - if you can trust them (nobody's verified them and they may be estimated for all you know). The self-retrieve distance they list for the B battery is 100km (63 miles) with a 800m launch with no ballast. Now add ballast, add an 3,000 ft obstacle and a 20kt headwind (all realistic conditions at Ely) and refigure what the hypothetical retrieve distance is, if any.
>
Take a look at this page: https://www.gpgliders.com/offer/gp-15-e-se-jeta Here's the pertinent
portion:

Usable battery capacity: 9,23 kWh
Operational battery capacity: 8,36 kWh (10% buffer to preserve battery life)
Weight: 52 kg (115 lb)

Motor glider’s self-launch and climb performance on a single charge, equipped with “B” battery
pack (TOW: 320 kg [705 lb]):

5 x take-off and climb to 800 m (2 625 ft) altitude
or 1 x take-off and climb to 800 m (2 625 ft) altitude + 150 km (93 mi) range
or 1 x take-off and total climb to >4 000 m (>13 120 ft)
Max. climb rate: >4,4 m/s (>8,55 kts)
Ground-roll take-off distance: 180 m (197 yards)

Because the wing area is 84 ft2, the 705lb TOW = 8.4 lb/ft2, about the same wing loading I have
in the ASH26E, unballasted.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Dave Nadler

March 17th 21, 11:28 PM

On 2/24/2021 4:41 PM, Dave Nadler wrote:
> https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
>
> Discuss amongst yourselves...

I'm glad to see this has generated some good discussion, but there were
a few rather bizarre posts. To be extremely clear:

1) I'm not "hating" on anyone, and I sincerely wish success for the
manufacturers, even those who have behaved badly...

2) The purpose of the post, for those it seems lost on, was to
illustrate that even the big boys in industry with colossal resources at
their disposal have problems. This stuff (electronics in general and
certainly battery storage and propulsion systems) is not easy.

3) Because it is not easy, the manner in which engineering is approached
matters. A lot. I've spent decades unsnarling engineering problems of
all stripes, and certainly in gliding I've seen how the sausages are
made. And I've seen, and continue to see how the same mistakes are
repeated and repeated...

I hope this all has helped general understanding of the issues,
Best Regards, Dave

PS: Really now, How Hard Could It Be?

March 18th 21, 03:59 AM

On Wednesday, March 17, 2021 at 4:28:20 PM UTC-7, wrote:
> On 2/24/2021 4:41 PM, Dave Nadler wrote:
> > https://insideevs.com/news/490300/hyundai-announces-massive-battery-reacall-82000-bevs/
> >
> > Discuss amongst yourselves...
>
> I'm glad to see this has generated some good discussion, but there were
> a few rather bizarre posts. To be extremely clear:
>
> 1) I'm not "hating" on anyone, and I sincerely wish success for the
> manufacturers, even those who have behaved badly...
>
> 2) The purpose of the post, for those it seems lost on, was to
> illustrate that even the big boys in industry with colossal resources at
> their disposal have problems. This stuff (electronics in general and
> certainly battery storage and propulsion systems) is not easy.
>
> 3) Because it is not easy, the manner in which engineering is approached
> matters. A lot. I've spent decades unsnarling engineering problems of
> all stripes, and certainly in gliding I've seen how the sausages are
> made. And I've seen, and continue to see how the same mistakes are
> repeated and repeated...
>
> I hope this all has helped general understanding of the issues,
> Best Regards, Dave
>
> PS: Really now, How Hard Could It Be?

I would appreciate hearing from you what problems you have had with your Antares if you are interested in sharing. Eric seems to think that all of these problems have been solved, but I am not convinced. In fact, significant new problems have materialized that weren't present in the Antares, like fires.

Tom

India November[_2_]

March 18th 21, 03:50 PM

On Wednesday, March 17, 2021 at 9:00:04 AM UTC-4, Eric Greenwell wrote:
> 2G wrote on 3/16/2021 10:17 PM:
> > On Tuesday, March 16, 2021 at 3:48:54 PM UTC-7, Eric Greenwell wrote:
> >> 2G wrote on 3/16/2021 12:46 PM:
> >>> Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it.
> >> I forgot to respond to the "non-motorized" portion of your remarks. Perhaps you will be
> >> surprised (or at least interested) to learn the GP15 climb rate from the runway on a typical
> >> flying day at Ely will be nearly double the climb rate of my ASH26E. A major reason is the
> >> electric motor still has the same power at 9000' DA, while the carbureted Wankel has lost about
> >> 18%. The better climb on takeoff in high density altitudes was an important factor in my
> >> choice. It's not important at Ely, but it is at Parowan, and a few other places I've flown (or
> >> wanted to fly but decided it was marginal).
> >>
> >> Now, I realize you think 90 miles of self-retrieve is the same as zero miles, but that view is
> >> not shared by every "pure" glider pilot out there!
> >> --
> >> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >> - "A Guide to Self-Launching Sailplane Operation"
> >> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > Where do you get 90 miles? GP's website doesn't list it. Their numbers are dry - if you can trust them (nobody's verified them and they may be estimated for all you know). The self-retrieve distance they list for the B battery is 100km (63 miles) with a 800m launch with no ballast. Now add ballast, add an 3,000 ft obstacle and a 20kt headwind (all realistic conditions at Ely) and refigure what the hypothetical retrieve distance is, if any.
> >
> Take a look at this page: https://www.gpgliders.com/offer/gp-15-e-se-jeta Here's the pertinent
> portion:
>
> Usable battery capacity: 9,23 kWh
> Operational battery capacity: 8,36 kWh (10% buffer to preserve battery life)
> Weight: 52 kg (115 lb)
>
> Motor gliderâ€™s self-launch and climb performance on a single charge, equipped with â€œBâ€ battery
> pack (TOW: 320 kg [705 lb]):
>
> 5 x take-off and climb to 800 m (2 625 ft) altitude
> or 1 x take-off and climb to 800 m (2 625 ft) altitude + 150 km (93 mi) range
> or 1 x take-off and total climb to >4 000 m (>13 120 ft)
> Max. climb rate: >4,4 m/s (>8,55 kts)
> Ground-roll take-off distance: 180 m (197 yards)
>
> Because the wing area is 84 ft2, the 705lb TOW = 8.4 lb/ft2, about the same wing loading I have
> in the ASH26E, unballasted.
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Eric, I'm curious about the wing loadings quoted for the Jeta from 7,58-13,72 lb/ft^2. For the conditions I fly in Ontario where thermals average 2 to 4 kts, I see these heavy wing loadings as a disadvantage even in a flapped ship. I fly my D2 mostly dry at less than 6 lb/ft^2. What am I missing?
Ian IN

Mark Mocho

March 18th 21, 06:30 PM

I fly my D2 mostly dry at less than 6 lb/ft^2. What am I missing?

Decent lift.

Dave Nadler

March 18th 21, 07:48 PM

On 3/18/2021 11:50 AM, India November wrote:
> Eric, I'm curious about the wing loadings quoted for the Jeta from 7,58-13,72 lb/ft^2. For the conditions I fly in Ontario where thermals average 2 to 4 kts, I see these heavy wing loadings as a disadvantage even in a flapped ship. I fly my D2 mostly dry at less than 6 lb/ft^2. What am I missing?

Ian, newer flapped designs do well in weak conditions even with higher
wing-loadings. The glider I'm flying at the moment has a minimum
wing-loading of 9.5 lbs/ft2 (and I'm a lighter pilot), but I've never
landed it when someone else was able to climb away. Span-loading helps
(18m better than 15m). Not comparable to older unflapped designs.

Eric Greenwell[_4_]

March 18th 21, 09:42 PM

India November wrote on 3/18/2021 8:50 AM:
> On Wednesday, March 17, 2021 at 9:00:04 AM UTC-4, Eric Greenwell wrote:
>> 2G wrote on 3/16/2021 10:17 PM:
>>> On Tuesday, March 16, 2021 at 3:48:54 PM UTC-7, Eric Greenwell wrote:
>>>> 2G wrote on 3/16/2021 12:46 PM:
>>>>> Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it.
>>>> I forgot to respond to the "non-motorized" portion of your remarks. Perhaps you will be
>>>> surprised (or at least interested) to learn the GP15 climb rate from the runway on a typical
>>>> flying day at Ely will be nearly double the climb rate of my ASH26E. A major reason is the
>>>> electric motor still has the same power at 9000' DA, while the carbureted Wankel has lost about
>>>> 18%. The better climb on takeoff in high density altitudes was an important factor in my
>>>> choice. It's not important at Ely, but it is at Parowan, and a few other places I've flown (or
>>>> wanted to fly but decided it was marginal).
>>>>
>>>> Now, I realize you think 90 miles of self-retrieve is the same as zero miles, but that view is
>>>> not shared by every "pure" glider pilot out there!
>>>> --
>>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
>>>> - "A Guide to Self-Launching Sailplane Operation"
>>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>>>
>>> Where do you get 90 miles? GP's website doesn't list it. Their numbers are dry - if you can trust them (nobody's verified them and they may be estimated for all you know). The self-retrieve distance they list for the B battery is 100km (63 miles) with a 800m launch with no ballast. Now add ballast, add an 3,000 ft obstacle and a 20kt headwind (all realistic conditions at Ely) and refigure what the hypothetical retrieve distance is, if any.
>>>
>> Take a look at this page: https://www.gpgliders.com/offer/gp-15-e-se-jeta Here's the pertinent
>> portion:
>>
>> Usable battery capacity: 9,23 kWh
>> Operational battery capacity: 8,36 kWh (10% buffer to preserve battery life)
>> Weight: 52 kg (115 lb)
>>
>> Motor glider’s self-launch and climb performance on a single charge, equipped with “B” battery
>> pack (TOW: 320 kg [705 lb]):
>>
>> 5 x take-off and climb to 800 m (2 625 ft) altitude
>> or 1 x take-off and climb to 800 m (2 625 ft) altitude + 150 km (93 mi) range
>> or 1 x take-off and total climb to >4 000 m (>13 120 ft)
>> Max. climb rate: >4,4 m/s (>8,55 kts)
>> Ground-roll take-off distance: 180 m (197 yards)
>>
>> Because the wing area is 84 ft2, the 705lb TOW = 8.4 lb/ft2, about the same wing loading I have
>> in the ASH26E, unballasted.

> Eric, I'm curious about the wing loadings quoted for the Jeta from 7,58-13,72 lb/ft^2. For the conditions I fly in Ontario where thermals average 2 to 4 kts, I see these heavy wing loadings as a disadvantage even in a flapped ship. I fly my D2 mostly dry at less than 6 lb/ft^2. What am I missing?
> Ian IN
>
Are you really sure of that wing loading? The numbers on the Schmepp site suggest a wing
loading for a pilot 165lb pilot with a 15 lb parachute is over 6.5 lb/ft2. But even it's 7
lb/ft2, it is definitely a lighter wing loading than the newer flapped 15m gliders; eg, the new
AS33-15M has a minimum wing loading of 8.5 lb/ft2, and that is without a motor.

As Dave mentions, span loading (weight/span^2) is a better indicator of thermalling ability,
and since the Discus 2A and the Jeta have the same span and about the same minimum weight
(using the weight from the Schmepp site), I'd expect them to thermal the same. It may seem
strange a lighter wing loading doesn't help more, but aspect ratio matters: the Discus has a 22
ratio, while the Jeta has 29.

And, the Jeta has a motor, so even if it did not thermal quite as well as your Discus, you'd
still have fewer landouts in it than the Discus 2. Plus, you'd love the extra speed the higher
wing loading allows during the cruise, at least 15% faster (and with a higher glide ratio, due
in part to the higher aspect ratio).

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

waremark

March 18th 21, 11:07 PM

On Thursday, 18 March 2021 at 19:48:23 UTC, wrote:

> Ian, newer flapped designs do well in weak conditions even with higher
> wing-loadings. The glider I'm flying at the moment has a minimum
> wing-loading of 9.5 lbs/ft2 (and I'm a lighter pilot), but I've never
> landed it when someone else was able to climb away. Span-loading helps
> (18m better than 15m). Not comparable to older unflapped designs.

When flying the Arcus M with a copilot and no ballast my wing loading is 49 kg/m2 (10 lbs/ft2). In spite of being a 'newer flapped design', in very weak lift pure gliders without ballast simply climb away from me. You may rightly assume that is indicative of my piloting skills, or lack of them! But when a good pilot joined me for a comp, the first time he was flying in very weak lift he quickly admitted that I hadn't been fibbing about not being able to climb in weak lift.

Dave Nadler

March 18th 21, 11:22 PM

On 3/17/2021 11:59 PM, 2G wrote:
> ...significant new problems have materialized that weren't present in the Antares, like fires.

2 of 4 Antares in USA had notable fires about a decade back (also some
in Europe). These fires were from unspeakably bad electronics design and
nothing to do with the battery system. Fortunately both fires in USA
happened on the ground without too much drama (burned up an electronic
module without spreading).

Dave Nadler

March 19th 21, 03:04 AM

On 3/18/2021 7:07 PM, waremark wrote:
> When flying the Arcus M with a copilot and no ballast my wing loading is 49 kg/m2 (10 lbs/ft2). In spite of being a 'newer flapped design', in very weak lift pure gliders without ballast simply climb away from me. You may rightly assume that is indicative of my piloting skills, or lack of them!

I wasn't going to say anything...

ArcusM isn't quite as good in weak lift, but anyway it's minimum loading
is MUCH higher than the Jeta; IIRC for me and usual passengers ArcusM
was around 9.5 also. Also Ian's comparing to a non-flapped glider...

India November[_2_]

March 19th 21, 02:23 PM

On Thursday, March 18, 2021 at 5:42:22 PM UTC-4, Eric Greenwell wrote:
> India November wrote on 3/18/2021 8:50 AM:
> > On Wednesday, March 17, 2021 at 9:00:04 AM UTC-4, Eric Greenwell wrote:
> >> 2G wrote on 3/16/2021 10:17 PM:
> >>> On Tuesday, March 16, 2021 at 3:48:54 PM UTC-7, Eric Greenwell wrote:
> >>>> 2G wrote on 3/16/2021 12:46 PM:
> >>>>> Landing out in eastern Nevada is serious business; some may chose to fly non-motorized gliders there (which, in my mind, the GP15 is) and get away with it.
> >>>> I forgot to respond to the "non-motorized" portion of your remarks. Perhaps you will be
> >>>> surprised (or at least interested) to learn the GP15 climb rate from the runway on a typical
> >>>> flying day at Ely will be nearly double the climb rate of my ASH26E. A major reason is the
> >>>> electric motor still has the same power at 9000' DA, while the carbureted Wankel has lost about
> >>>> 18%. The better climb on takeoff in high density altitudes was an important factor in my
> >>>> choice. It's not important at Ely, but it is at Parowan, and a few other places I've flown (or
> >>>> wanted to fly but decided it was marginal).
> >>>>
> >>>> Now, I realize you think 90 miles of self-retrieve is the same as zero miles, but that view is
> >>>> not shared by every "pure" glider pilot out there!
> >>>> --
> >>>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> >>>> - "A Guide to Self-Launching Sailplane Operation"
> >>>> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >>>
> >>> Where do you get 90 miles? GP's website doesn't list it. Their numbers are dry - if you can trust them (nobody's verified them and they may be estimated for all you know). The self-retrieve distance they list for the B battery is 100km (63 miles) with a 800m launch with no ballast. Now add ballast, add an 3,000 ft obstacle and a 20kt headwind (all realistic conditions at Ely) and refigure what the hypothetical retrieve distance is, if any.
> >>>
> >> Take a look at this page: https://www.gpgliders.com/offer/gp-15-e-se-jeta Here's the pertinent
> >> portion:
> >>
> >> Usable battery capacity: 9,23 kWh
> >> Operational battery capacity: 8,36 kWh (10% buffer to preserve battery life)
> >> Weight: 52 kg (115 lb)
> >>
> >> Motor gliderâ€™s self-launch and climb performance on a single charge, equipped with â€œBâ€ battery
> >> pack (TOW: 320 kg [705 lb]):
> >>
> >> 5 x take-off and climb to 800 m (2 625 ft) altitude
> >> or 1 x take-off and climb to 800 m (2 625 ft) altitude + 150 km (93 mi) range
> >> or 1 x take-off and total climb to >4 000 m (>13 120 ft)
> >> Max. climb rate: >4,4 m/s (>8,55 kts)
> >> Ground-roll take-off distance: 180 m (197 yards)
> >>
> >> Because the wing area is 84 ft2, the 705lb TOW = 8.4 lb/ft2, about the same wing loading I have
> >> in the ASH26E, unballasted.
> > Eric, I'm curious about the wing loadings quoted for the Jeta from 7,58-13,72 lb/ft^2. For the conditions I fly in Ontario where thermals average 2 to 4 kts, I see these heavy wing loadings as a disadvantage even in a flapped ship. I fly my D2 mostly dry at less than 6 lb/ft^2. What am I missing?
> > Ian IN
> >
> Are you really sure of that wing loading? The numbers on the Schmepp site suggest a wing
> loading for a pilot 165lb pilot with a 15 lb parachute is over 6.5 lb/ft2.. But even it's 7
> lb/ft2, it is definitely a lighter wing loading than the newer flapped 15m gliders; eg, the new
> AS33-15M has a minimum wing loading of 8.5 lb/ft2, and that is without a motor.
>
> As Dave mentions, span loading (weight/span^2) is a better indicator of thermalling ability,
> and since the Discus 2A and the Jeta have the same span and about the same minimum weight
> (using the weight from the Schmepp site), I'd expect them to thermal the same. It may seem
> strange a lighter wing loading doesn't help more, but aspect ratio matters: the Discus has a 22
> ratio, while the Jeta has 29.
>
> And, the Jeta has a motor, so even if it did not thermal quite as well as your Discus, you'd
> still have fewer landouts in it than the Discus 2. Plus, you'd love the extra speed the higher
> wing loading allows during the cruise, at least 15% faster (and with a higher glide ratio, due
> in part to the higher aspect ratio).
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Interesting, thanks Eric. And yes, I meant 6.8ppsf min loading in my D2. What was I thinking!
Ian IN

kinsell

March 20th 21, 12:26 AM

On 3/12/21 1:38 AM, wrote:
> On Friday, 12 March 2021 at 04:33:55 UTC+1, Eric Greenwell wrote:
>>
>> I don't think it will take 15+ more years for electric gliders to be accepted and desired like
>> gas powered gliders are now. With FES and mast-mounted electrics available from all the major
>> manufacturers, I think this year is the "tipping point", and sales of electrics will "soon"
>> increase faster than the gas powered sales; unfortunately, I don't know of any good way to
>> track sales.
>
> Just one datapoint, Jonker in their latest newsletter reported the following about their electrical JS3 RES:
> "The first 5 JS3 RES gliders are currently in production with another 30 planned for 2021."
> If they plan to produce 35 electrical JS3s in 2021, I assume that will be most of their production of JS3s. They produced their 100th JS3 last year, 4 years after it was introduced, so up until then average production was around 25 per year.
>
> Of course, they don't have any combustion engine self launch version of the JS3 to compare with, though the heavily delayed JS2 is about to enter production. Don't know any order numbers for that one.
>

When it comes to 'heavily delayed', nothing can hold a candle to the
GP-14 and 15. In August, we heard they hoped to freeze the overall
design of the units in Q1. As Q1 grinds to an end, wonder what they're
telling aspiring customers now? They've gone uncharacteristically quiet
on social media. The picture of the (former) RK glider sitting in the
snow is getting a bit stale.

waremark

March 23rd 21, 12:22 AM

On Friday, 19 March 2021 at 03:04:04 UTC, wrote:
> On 3/18/2021 7:07 PM, waremark wrote:
> > When flying the Arcus M with a copilot and no ballast my wing loading is 49 kg/m2 (10 lbs/ft2). In spite of being a 'newer flapped design', in very weak lift pure gliders without ballast simply climb away from me. You may rightly assume that is indicative of my piloting skills, or lack of them!
> I wasn't going to say anything...
>
> ArcusM isn't quite as good in weak lift, but anyway it's minimum loading
> is MUCH higher than the Jeta; IIRC for me and usual passengers ArcusM
> was around 9.5 also. Also Ian's comparing to a non-flapped glider...

It was a different glider in 2020 - when for Covid social distancing reasons I always flew it solo!

Nicholas Kennedy

March 31st 21, 04:41 PM

https://www.msn.com/en-us/news/technology/battery-powered-by-nuclear-waste-will-run-for-28000-years/ar-BB1fa3aZ?ocid=msedgdhp

This is IT! No more pesky recharging problem.
No more limited self retrieve range!
Sign me up!
Nick
T

Hank Nixon

March 31st 21, 05:12 PM

On Friday, March 19, 2021 at 8:26:29 PM UTC-4, kinsell wrote:
> On 3/12/21 1:38 AM, wrote:
> > On Friday, 12 March 2021 at 04:33:55 UTC+1, Eric Greenwell wrote:
> >>
> >> I don't think it will take 15+ more years for electric gliders to be accepted and desired like
> >> gas powered gliders are now. With FES and mast-mounted electrics available from all the major
> >> manufacturers, I think this year is the "tipping point", and sales of electrics will "soon"
> >> increase faster than the gas powered sales; unfortunately, I don't know of any good way to
> >> track sales.
> >
> > Just one datapoint, Jonker in their latest newsletter reported the following about their electrical JS3 RES:
> > "The first 5 JS3 RES gliders are currently in production with another 30 planned for 2021."
> > If they plan to produce 35 electrical JS3s in 2021, I assume that will be most of their production of JS3s. They produced their 100th JS3 last year, 4 years after it was introduced, so up until then average production was around 25 per year.
> >
> > Of course, they don't have any combustion engine self launch version of the JS3 to compare with, though the heavily delayed JS2 is about to enter production. Don't know any order numbers for that one.
> >
>
> When it comes to 'heavily delayed', nothing can hold a candle to the
> GP-14 and 15. In August, we heard they hoped to freeze the overall
> design of the units in Q1. As Q1 grinds to an end, wonder what they're
> telling aspiring customers now? They've gone uncharacteristically quiet
> on social media. The picture of the (former) RK glider sitting in the
> snow is getting a bit stale.

The US rep has sent an update message to those on his circulation list.
UH

March 31st 21, 05:22 PM

On Wednesday, March 31, 2021 at 8:41:34 AM UTC-7, wrote:
> https://www.msn.com/en-us/news/technology/battery-powered-by-nuclear-waste-will-run-for-28000-years/ar-BB1fa3aZ?ocid=msedgdhp

Debunked:

https://www.youtube.com/watch?v=uzV_uzSTCTM

kinsell

March 31st 21, 06:31 PM

On 3/31/21 10:12 AM, Hank Nixon wrote:
> On Friday, March 19, 2021 at 8:26:29 PM UTC-4, kinsell wrote:
>> On 3/12/21 1:38 AM, wrote:
>>> On Friday, 12 March 2021 at 04:33:55 UTC+1, Eric Greenwell wrote:
>>>>
>>>> I don't think it will take 15+ more years for electric gliders to be accepted and desired like
>>>> gas powered gliders are now. With FES and mast-mounted electrics available from all the major
>>>> manufacturers, I think this year is the "tipping point", and sales of electrics will "soon"
>>>> increase faster than the gas powered sales; unfortunately, I don't know of any good way to
>>>> track sales.
>>>
>>> Just one datapoint, Jonker in their latest newsletter reported the following about their electrical JS3 RES:
>>> "The first 5 JS3 RES gliders are currently in production with another 30 planned for 2021."
>>> If they plan to produce 35 electrical JS3s in 2021, I assume that will be most of their production of JS3s. They produced their 100th JS3 last year, 4 years after it was introduced, so up until then average production was around 25 per year.
>>>
>>> Of course, they don't have any combustion engine self launch version of the JS3 to compare with, though the heavily delayed JS2 is about to enter production. Don't know any order numbers for that one.
>>>
>>
>> When it comes to 'heavily delayed', nothing can hold a candle to the
>> GP-14 and 15. In August, we heard they hoped to freeze the overall
>> design of the units in Q1. As Q1 grinds to an end, wonder what they're
>> telling aspiring customers now? They've gone uncharacteristically quiet
>> on social media. The picture of the (former) RK glider sitting in the
>> snow is getting a bit stale.
>
> The US rep has sent an update message to those on his circulation list.
> UH
>

That's nice. But at some point they need to deliver actual working
gliders. Working gliders that meet their amazing specs would be even
better. Could happen, but their past history does not give one much
hope. I have multiple friends who have these things on order, I hope
it does work out for their sake, but won't be holding my breath. Like
they say, hope is not a strategy.

March 31st 21, 08:34 PM

On Wednesday, March 31, 2021 at 8:41:34 AM UTC-7, wrote:
> https://www.msn.com/en-us/news/technology/battery-powered-by-nuclear-waste-will-run-for-28000-years/ar-BB1fa3aZ?ocid=msedgdhp
>
> This is IT! No more pesky recharging problem.
> No more limited self retrieve range!
> Sign me up!
> Nick
> T
It's a day early for APRIL FOOLS!

Dave Nadler

March 31st 21, 11:23 PM

On 3/7/2021 11:30 PM, 2G wrote:
> Why don't you start by naming JUST ONE that replaced an ICE with an electric.

Somehow I failed to post this earlier:
Patrick McLaughlin designed/built/debugged/delivered an electric
self-launch version of the Sparrowhawk some years ago (called the Owl).
Not a ICDE replacement, but a scratch-built pylon electric
self-launcher. Of course he's a bit more capable than most of us ;-)

Charlie M. (UH & 002 owner/pilot)

March 31st 21, 11:49 PM

On Wednesday, March 31, 2021 at 11:41:34 AM UTC-4, wrote:
> https://www.msn.com/en-us/news/technology/battery-powered-by-nuclear-waste-will-run-for-28000-years/ar-BB1fa3aZ?ocid=msedgdhp
>
> This is IT! No more pesky recharging problem.
> No more limited self retrieve range!
> Sign me up!
> Nick
> T
Good news, the heat off the "pile" can keep you warm in wave flights!
I'm thinking of "the Martian".......sorta real info although a movie....

Hank Nixon

April 1st 21, 12:25 AM

On Sunday, March 7, 2021 at 11:30:14 PM UTC-5, 2G wrote:
> On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > > your potential retrieve distance is shorter, instead of an imminent landing.
> > I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
> >
> > I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> >
> > Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
>
> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
>
> Tom
i missed the comment above but will name one who has replaced ICE with electric. That would be me. My ASW-24E(L) has been flying for over a year and has done the first self launch.
UH

Charlie M. (UH & 002 owner/pilot)

April 1st 21, 01:41 AM

On Wednesday, March 31, 2021 at 7:25:19 PM UTC-4, Hank Nixon wrote:
> On Sunday, March 7, 2021 at 11:30:14 PM UTC-5, 2G wrote:
> > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > > > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > > > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > > > your potential retrieve distance is shorter, instead of an imminent landing.
> > > I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
> > >
> > > I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > >
> > > Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> >
> > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> >
> > Tom
> i missed the comment above but will name one who has replaced ICE with electric. That would be me. My ASW-24E(L) has been flying for over a year and has done the first self launch.
> UH
And maybe this spring I get current enough to try it out....
"How hard could it be?"..

Eric Greenwell[_4_]

April 1st 21, 03:21 AM

Dave Nadler wrote on 3/31/2021 3:23 PM:
> On 3/7/2021 11:30 PM, 2G wrote:
>> Why don't you start by naming JUST ONE that replaced an ICE with an electric.
>
> Somehow I failed to post this earlier:
> Patrick McLaughlin designed/built/debugged/delivered an electric self-launch version of the
> Sparrowhawk some years ago (called the Owl).
> Not a ICDE replacement, but a scratch-built pylon electric self-launcher. Of course he's a bit
> more capable than most of us ;-)

I did not know that. Is it documented somewhere accessible?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

kinsell

April 1st 21, 04:17 AM

On 3/16/21 12:44 PM, Mark Mocho wrote:
> Don't suppose you went to Poland to verify the performance
> numbers?
>
> Are there actually any GP-15 gliders in the hands of private owners? Or are they still on some imaginary delivery schedule? The only one I know of that was in the US was sent back for "upgrades." Don't know if it actually flew before going "home."
>

Both the one delivered to the U.S., and the factory demonstrator were
recently sold on W&W. Possibly the demonstrator will be in the hands of
a customer RSN. Has the small batteries from what I understand, and not
sure what they did with the wings. The one initially delivered to the
U.S. never got a flight in (without the help of a couple big turbofans).

Dave Nadler

April 1st 21, 02:58 PM

On 3/31/2021 10:21 PM, Eric Greenwell wrote:
> Dave Nadler wrote on 3/31/2021 3:23 PM:
>> On 3/7/2021 11:30 PM, 2G wrote:
>>> Why don't you start by naming JUST ONE that replaced an ICE with an
>>> electric.
>>
>> Somehow I failed to post this earlier:
>> Patrick McLaughlin designed/built/debugged/delivered an electric
>> self-launch version of the Sparrowhawk some years ago (called the Owl).
>> Not a ICE replacement, but a scratch-built pylon electric
>> self-launcher. Of course he's a bit more capable than most of us ;-)
>
> I did not know that. Is it documented somewhere accessible?

Probably in the "Complete guide to self-launch sailplanes" or somewhere...

Dan Marotta

April 1st 21, 05:43 PM

What a neat idea! But all of the stacked cells would make your cell
phone weitg on the order of 37 pounds... And the required lead
shielding would another 213 pounds. So you'd need a new Tesla pickup to
cart the thing around...

Dan
5J

On 3/31/21 9:41 AM, Nicholas Kennedy wrote:
> https://www.msn.com/en-us/news/technology/battery-powered-by-nuclear-waste-will-run-for-28000-years/ar-BB1fa3aZ?ocid=msedgdhp
>
> This is IT! No more pesky recharging problem.
> No more limited self retrieve range!
> Sign me up!
> Nick
> T
>

Dan Marotta

April 1st 21, 05:48 PM

Well Charlie,

Since you're a fan of "The Martian" (one of my all-time favorites, BTW),
can you explain to me why JPL had him cut a hole in the top of the rover
and place an inflated balloon in it?

Inquiring minds...

Dan
5J

On 3/31/21 4:49 PM, Charlie M. (UH & 002 owner/pilot) wrote:
> On Wednesday, March 31, 2021 at 11:41:34 AM UTC-4, wrote:
>> https://www.msn.com/en-us/news/technology/battery-powered-by-nuclear-waste-will-run-for-28000-years/ar-BB1fa3aZ?ocid=msedgdhp
>>
>> This is IT! No more pesky recharging problem.
>> No more limited self retrieve range!
>> Sign me up!
>> Nick
>> T
> Good news, the heat off the "pile" can keep you warm in wave flights!
> I'm thinking of "the Martian".......sorta real info although a movie....
>

April 2nd 21, 05:40 AM

On Wednesday, March 31, 2021 at 4:25:19 PM UTC-7, Hank Nixon wrote:
> On Sunday, March 7, 2021 at 11:30:14 PM UTC-5, 2G wrote:
> > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > > > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > > > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > > > your potential retrieve distance is shorter, instead of an imminent landing.
> > > I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
> > >
> > > I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > >
> > > Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> >
> > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> >
> > Tom
> i missed the comment above but will name one who has replaced ICE with electric. That would be me. My ASW-24E(L) has been flying for over a year and has done the first self launch.
> UH

And you missed my reply to whomever pointed that out. Basically, you did it to achieve self-launch capability and the effort involved was not worth it..

Hank Nixon

April 2nd 21, 01:35 PM

On Friday, April 2, 2021 at 12:40:11 AM UTC-4, 2G wrote:
> On Wednesday, March 31, 2021 at 4:25:19 PM UTC-7, Hank Nixon wrote:
> > On Sunday, March 7, 2021 at 11:30:14 PM UTC-5, 2G wrote:
> > > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > > > > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > > > > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > > > > your potential retrieve distance is shorter, instead of an imminent landing.
> > > > I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
> > > >
> > > > I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > > >
> > > > Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> > >
> > > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> > >
> > > Tom
> > i missed the comment above but will name one who has replaced ICE with electric. That would be me. My ASW-24E(L) has been flying for over a year and has done the first self launch.
> > UH
> And you missed my reply to whomever pointed that out. Basically, you did it to achieve self-launch capability and the effort involved was not worth it.

It was worth it to me. My objective was(is) a self launching sailplane of practical size and weight for regular assembly and disassembly that I can fly when I don't have a towplane available. This may not meet your needs or objectives. It has been an interesting and challenging project, not without setbacks. A good project for a retired engineer and sailplane modifier that wanted something interesting to do. You seem to think that something that does not meet your needs is not worthwhile. An open mind that sees that there are many valid points of view is a good thing.
That said, I'm not suggesting that others that don't have my experience, time, and resources try do do the same thing.
How hard could it be?
UH

April 3rd 21, 08:21 PM

On Friday, April 2, 2021 at 5:35:53 AM UTC-7, Hank Nixon wrote:
> On Friday, April 2, 2021 at 12:40:11 AM UTC-4, 2G wrote:
> > On Wednesday, March 31, 2021 at 4:25:19 PM UTC-7, Hank Nixon wrote:
> > > On Sunday, March 7, 2021 at 11:30:14 PM UTC-5, 2G wrote:
> > > > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > > > > > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > > > > > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > > > > > your potential retrieve distance is shorter, instead of an imminent landing.
> > > > > I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
> > > > >
> > > > > I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > > > >
> > > > > Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> > > >
> > > > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> > > >
> > > > Tom
> > > i missed the comment above but will name one who has replaced ICE with electric. That would be me. My ASW-24E(L) has been flying for over a year and has done the first self launch.
> > > UH
> > And you missed my reply to whomever pointed that out. Basically, you did it to achieve self-launch capability and the effort involved was not worth it.
> It was worth it to me. My objective was(is) a self launching sailplane of practical size and weight for regular assembly and disassembly that I can fly when I don't have a towplane available. This may not meet your needs or objectives. It has been an interesting and challenging project, not without setbacks. A good project for a retired engineer and sailplane modifier that wanted something interesting to do. You seem to think that something that does not meet your needs is not worthwhile. An open mind that sees that there are many valid points of view is a good thing.
> That said, I'm not suggesting that others that don't have my experience, time, and resources try do do the same thing.
> How hard could it be?
> UH

I'm not suggesting anything - I raised the question of who had done this conversion when it was implied that several had done it because electric is so superior to ICE. Your final conclusion was that it is easier to buy an electric glider than to make this conversion (which I don't find surprising). Congratulations on successfully completing the project.

How hard could it be? A LOT DAMN HARDER than you think when beginning the project. And when you are done you have a one-of-a-kind glider that will be more difficult to sell than a production model.

Tom

Herbert kilian

April 5th 21, 04:33 PM

On Saturday, April 3, 2021 at 2:21:58 PM UTC-5, 2G wrote:
> On Friday, April 2, 2021 at 5:35:53 AM UTC-7, Hank Nixon wrote:
> > On Friday, April 2, 2021 at 12:40:11 AM UTC-4, 2G wrote:
> > > On Wednesday, March 31, 2021 at 4:25:19 PM UTC-7, Hank Nixon wrote:
> > > > On Sunday, March 7, 2021 at 11:30:14 PM UTC-5, 2G wrote:
> > > > > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > > > > > > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > > > > > > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > > > > > > your potential retrieve distance is shorter, instead of an imminent landing.
> > > > > > I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
> > > > > >
> > > > > > I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > > > > >
> > > > > > Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are.. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> > > > >
> > > > > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> > > > >
> > > > > Tom
> > > > i missed the comment above but will name one who has replaced ICE with electric. That would be me. My ASW-24E(L) has been flying for over a year and has done the first self launch.
> > > > UH
> > > And you missed my reply to whomever pointed that out. Basically, you did it to achieve self-launch capability and the effort involved was not worth it.
> > It was worth it to me. My objective was(is) a self launching sailplane of practical size and weight for regular assembly and disassembly that I can fly when I don't have a towplane available. This may not meet your needs or objectives. It has been an interesting and challenging project, not without setbacks. A good project for a retired engineer and sailplane modifier that wanted something interesting to do. You seem to think that something that does not meet your needs is not worthwhile. An open mind that sees that there are many valid points of view is a good thing.
> > That said, I'm not suggesting that others that don't have my experience, time, and resources try do do the same thing.
> > How hard could it be?
> > UH
> I'm not suggesting anything - I raised the question of who had done this conversion when it was implied that several had done it because electric is so superior to ICE. Your final conclusion was that it is easier to buy an electric glider than to make this conversion (which I don't find surprising). Congratulations on successfully completing the project.
>
> How hard could it be? A LOT DAMN HARDER than you think when beginning the project. And when you are done you have a one-of-a-kind glider that will be more difficult to sell than a production model.
>
> Tom
Tom, your negativity is sometimes hard to stomach. Please consider dialing it down, thank you. Please don't feel compelled to answer.

April 6th 21, 05:50 AM

On Monday, April 5, 2021 at 8:33:04 AM UTC-7, Herbert Kilian wrote:
> On Saturday, April 3, 2021 at 2:21:58 PM UTC-5, 2G wrote:
> > On Friday, April 2, 2021 at 5:35:53 AM UTC-7, Hank Nixon wrote:
> > > On Friday, April 2, 2021 at 12:40:11 AM UTC-4, 2G wrote:
> > > > On Wednesday, March 31, 2021 at 4:25:19 PM UTC-7, Hank Nixon wrote:
> > > > > On Sunday, March 7, 2021 at 11:30:14 PM UTC-5, 2G wrote:
> > > > > > On Thursday, March 4, 2021 at 1:55:30 PM UTC-8, Kenn Sebesta wrote:
> > > > > > > > A hybrid system with a gas engine wouldn't have the pucker factor associated with starting a
> > > > > > > > gas powered motorglider to avoid a landing: if the hybrid engine doesn't start, it just means
> > > > > > > > your potential retrieve distance is shorter, instead of an imminent landing.
> > > > > > > I'll wade in here with some experience. Top Flight, a Boston startup specializing in hybrid propulsion systems, spend over half a decade developing their power unit. The hardest part for them was developing a unit which was reliable. Motors don't like vibration and they don't like heat.. Combine the two together and the motor is not long for this world. It took a lot more R&D than anyone expected to make a lightweight package which could survive.
> > > > > > >
> > > > > > > I would not expect anyone to be deploying this technology anytime soon. If and when it is commercialized, it will be useful for ferry flights of electric aircraft. For any use which requires permanent installation, you're probably better having it drive the propeller directly.
> > > > > > >
> > > > > > > Re: eGliders, I sense a tone here which is reminiscent of discussions about finally putting the 2-33 to rest. The US is no longer the forefront of light aviation, so we need to look east to see what the trends are. We know that leading glider manufacturers are racing to bring eGliders to market. A gentleman who works on glider competition rules noted this summer that glider records are falling left and right to eGliders. There is a growing group of amateurs who are pulling their engines out of their gas self-launchers and replacing them with electric (If you'd like to be a part of this group, DM me). The future was yesterday, but like any future it doesn't arrive at all places at once.
> > > > > >
> > > > > > Why don't you start by naming JUST ONE that replaced an ICE with an electric.
> > > > > >
> > > > > > Tom
> > > > > i missed the comment above but will name one who has replaced ICE with electric. That would be me. My ASW-24E(L) has been flying for over a year and has done the first self launch.
> > > > > UH
> > > > And you missed my reply to whomever pointed that out. Basically, you did it to achieve self-launch capability and the effort involved was not worth it.
> > > It was worth it to me. My objective was(is) a self launching sailplane of practical size and weight for regular assembly and disassembly that I can fly when I don't have a towplane available. This may not meet your needs or objectives. It has been an interesting and challenging project, not without setbacks. A good project for a retired engineer and sailplane modifier that wanted something interesting to do. You seem to think that something that does not meet your needs is not worthwhile. An open mind that sees that there are many valid points of view is a good thing.
> > > That said, I'm not suggesting that others that don't have my experience, time, and resources try do do the same thing.
> > > How hard could it be?
> > > UH
> > I'm not suggesting anything - I raised the question of who had done this conversion when it was implied that several had done it because electric is so superior to ICE. Your final conclusion was that it is easier to buy an electric glider than to make this conversion (which I don't find surprising). Congratulations on successfully completing the project.
> >
> > How hard could it be? A LOT DAMN HARDER than you think when beginning the project. And when you are done you have a one-of-a-kind glider that will be more difficult to sell than a production model.
> >
> > Tom
> Tom, your negativity is sometimes hard to stomach. Please consider dialing it down, thank you. Please don't feel compelled to answer.

Herb, I call em like I see em - sometimes that's negative. I guess you missed my post about the wonderful WW2 story.