Reiner Stemme's new electric glider.

[Glidingstuff[_2_]]

Being announced at Aero 2016 this week is Dr Stemmes new glider designs.

Not in english as yet but here is some detail.

http://www.rs-uas.com/products/sk10e-elfin/preface/

This is his new company. Reiner Stemme Utility Air Systems.

[krasw]

So he has nothing to do with old Stemme company? Interesting.

Putting range extender on glider is a good idea. They are being made everywhere for electric cars and should be affordable (when mass produced). Surprising that the weight of pod is 100kg. That's one big range extender. No wonder they couldn't fit it in the fuselage.

[Dan Marotta]

Not speaking German and too lazy to do a lot of cutting and pasting in
google translate, I'll ask here: What is the range capability with the
range extender? And how long does it take to recharge? Does it have
some solar charging capability?

My old-fashioned fossil fuel powered Stemme will take off, climb to
14,000' (30,000' service ceiling, but that's just too cold), cruise for
500 miles at about 130 kts ground speed, and can be "recharged" in about
10 minutes at the pump. That's pretty hard to beat! That said, since
bringing it home I've flown it around 13 hours and used about 11 gallons
of gas, maybe 12... As the season improves, I'll probably be able to
fly another 25 or 30 hours before needing to refuel (unless I want the
ballast).

On 4/21/2016 1:51 AM, krasw wrote:
> So he has nothing to do with old Stemme company? Interesting.
>
> Putting range extender on glider is a good idea. They are being made everywhere for electric cars and should be affordable (when mass produced). Surprising that the weight of pod is 100kg. That's one big range extender. No wonder they couldn't fit it in the fuselage.

--
Dan, 5J

[krasw]

On Thursday, 21 April 2016 17:19:05 UTC+3, Dan Marotta wrote:
> Not speaking German and too lazy to do a lot of cutting and pasting
> in google translate, I'll ask here:* What is the range capability
> with the range extender?* And how long does it take to recharge?*
> Does it have some solar charging capability?
>
>
>
> My old-fashioned fossil fuel powered Stemme will take off, climb to
> 14,000' (30,000' service ceiling, but that's just too cold), cruise
> for 500 miles at about 130 kts ground speed, and can be "recharged"
> in about 10 minutes at the pump.* That's pretty hard to beat!* That
> said, since bringing it home I've flown it around 13 hours and used
> about 11 gallons of gas, maybe 12...* As the season improves, I'll
> probably be able to fly another 25 or 30 hours before needing to
> refuel (unless I want the ballast).
>
>
>
>
> On 4/21/2016 1:51 AM, krasw wrote:
>
>
>
> So he has nothing to do with old Stemme company? Interesting.
>
> Putting range extender on glider is a good idea. They are being made everywhere for electric cars and should be affordable (when mass produced). Surprising that the weight of pod is 100kg. That's one big range extender. No wonder they couldn't fit it in the fuselage.
>
>
>
>
>
> --
>
> Dan, 5J

1.000 km mit 185 km/h TAS (100 KTAS)

[Martin Gregorie[_5_]]

On Thu, 21 Apr 2016 08:18:53 -0600, Dan Marotta wrote:

>> Putting range extender on glider is a good idea. They are being made
>> everywhere for electric cars and should be affordable (when mass
>> produced). Surprising that the weight of pod is 100kg. That's one big
>> range extender. No wonder they couldn't fit it in the fuselage.
>
Not that surprising: the energy density of LiPoly/Li-ion batteries is low
by comparison with avgas.

A quick look round Wikipedia gives a figure of 0.1-0.25Kw/kg for Li-ion
batteries and 33.3kw/US gal. Since a US gallon of gas weighs 6.073 lbs
and there are 2.2 lbs to a kilogram, that gives 12Kw/kg for gasoline.
IOW on their figures gasoline has at least 48 times the energy density of
Li-ion batteries.

Now you know why the long range S-class Tesla totes 540kg of battery,
while a full tank in my Focus weighs around 50kg - (55 litres of petrol +
guessed 5kg of steel). Both have a similar driving range +/- 20%.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Martin Gregorie[_5_]]

On Thu, 21 Apr 2016 19:00:19 +0000, Martin Gregorie wrote:

> IOW on their figures gasoline has at least 48 times the energy density
> of Li-ion batteries.
>
On thinking about it, an energy density of 0.1-0.3 Kw/Kg seems a bit low
for a Li-ion/Li-poly battery and I'm wondering how old and outdated it
might be.

> .... the long range S-class Tesla totes 540kg of battery,
> while a full tank in my Focus weighs around 50kg - (55 litres of petrol
> + guessed 5kg of steel). Both have a similar driving range +/- 20%.

Comparing the S-class battery with my Focus fuel tank gives a an energy
density ratio (kw/kg) nearer 1:10 than the 1:48 given by Wikipedian
figures.

Does anybody have recent figures for best-of-breed Li-ion or similar
batteries?



--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Glidingstuff[_2_]]

> Does anybody have recent figures for best-of-breed Li-ion or similar
> batteries?

From what I gather from the translation is the pod is a self contained generator powered by a small gas engine. Complete with fuel tank. It plugs into the glider system and is used to provide a constant charge to keep the main batteries topped up. While soaring I assume it would be turned off and only run when needed. Maybe some solar panels on top of the fuse as well.

Not touring? Leave it in the hanger.

[Jonathan St. Cloud]

I thought it was a fuel cell they were testing

[son_of_flubber]

On Thursday, April 21, 2016 at 6:54:42 PM UTC-4, Jonathan St. Cloud wrote:
> I thought it was a fuel cell they were testing

I thought the wing pod was full of Li-Ion batteries. Automatically detaches when it overheats. Programmed to short and explode before it reaches the ground.

Seriously. Will Tesla brand Li-Ion batteries ever find their way into aircraft propulsion?

[Martin Gregorie[_5_]]

On Thu, 21 Apr 2016 14:49:57 -0700, Glidingstuff wrote:

>> Does anybody have recent figures for best-of-breed Li-ion or similar
>> batteries?
>
> From what I gather from the translation is the pod is a self contained
> generator powered by a small gas engine. Complete with fuel tank. It
> plugs into the glider system and is used to provide a constant charge to
> keep the main batteries topped up. While soaring I assume it would be
> turned off and only run when needed. Maybe some solar panels on top of
> the fuse as well.
>

That makes a lot of sense and also explains what looks like fairly large
intake and exhaust holes at each end of the pod.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[[email protected]]

On Thursday, April 21, 2016 at 4:56:52 PM UTC-7, son_of_flubber wrote:
> Seriously. Will Tesla brand Li-Ion batteries ever find their way into aircraft propulsion?

Tesla battery packs are currently made up from standard Panasonic 18650 li-ion cells with off-the-shelf charger/protection circuits, the same as in many laptop batteries. Not magic unobtanium, just buying in bulk.

[son_of_flubber]

On Thursday, April 21, 2016 at 8:27:02 PM UTC-4, wrote:
> On Thursday, April 21, 2016 at 4:56:52 PM UTC-7, son_of_flubber wrote:
> > Seriously. Will Tesla brand Li-Ion batteries ever find their way into aircraft propulsion?
>
> Tesla battery packs are currently made up from standard Panasonic 18650 li-ion cells with off-the-shelf charger/protection circuits, the same as in many laptop batteries. Not magic unobtanium, just buying in bulk.

Tesla's NV battery factory projects reducing battery costs by 30%.

[[email protected]]

On Thursday, April 21, 2016 at 5:32:30 PM UTC-7, son_of_flubber wrote:
> On Thursday, April 21, 2016 at 8:27:02 PM UTC-4, wrote:
> > On Thursday, April 21, 2016 at 4:56:52 PM UTC-7, son_of_flubber wrote:
> > > Seriously. Will Tesla brand Li-Ion batteries ever find their way into aircraft propulsion?
> >
> > Tesla battery packs are currently made up from standard Panasonic 18650 li-ion cells with off-the-shelf charger/protection circuits, the same as in many laptop batteries. Not magic unobtanium, just buying in bulk.
>
> Tesla's NV battery factory projects reducing battery costs by 30%.

So they say, still sounds like they're just going to produce 18650 cells via much automation. If it works, it will eventually drive down the price of all such cells.

[krasw]

On Friday, 22 April 2016 00:49:58 UTC+3, Glidingstuff wrote:
> > Does anybody have recent figures for best-of-breed Li-ion or similar
> > batteries?
>
> From what I gather from the translation is the pod is a self contained generator powered by a small gas engine. Complete with fuel tank. It plugs into the glider system and is used to provide a constant charge to keep the main batteries topped up.
>

Yes, it is engine driven generator. (Nobody in this forum can read german, really?)

[Martin Gregorie[_5_]]

On Thu, 21 Apr 2016 23:54:03 -0700, krasw wrote:

> Yes, it is engine driven generator. (Nobody in this forum can read
> german, really?)
>
Speaking for myself: one year of high school German mumble mumble decades
ago, a subscription to Vol Libre, while it existed, and 1-2 week visits
to Germany or Austria may do for getting food, beer and some place to
sleep but don't really cut it for technical stuff or staying current in a
language.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |