Which sustainer system would you chose for your sailplane?

[[email protected]]

Dear gliderpilots!

Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system:

http://www.front-electric-sustainer.com/voting.php

Thank you,

Luka

[waremark]

On Sunday, September 23, 2012 6:55:27 AM UTC+1, wrote:
> Dear gliderpilots!
>
>
>
> Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system:
>
>
>
> http://www.front-electric-sustainer.com/voting.php
>
>
>
> Thank you,
>
>
>
> Luka

Can you give us some facts on the comparison - price, weight incl fuel, endurance in amount of climb available, rate of climb. Take typical 18m gliders, presumable LAK for the FES and Solo, JS1 for the jet.

Does the FES prop have any effect on performance? For how many gliders is it certified, because for many they choose the glider first, and take the system which is available with that glider?

And why not include self launch options? I fly an ASH 26E, and I like that when I need to start up over a field I am more confident that everything will work because I used it to take off today, I have an electric start, and when it starts (in 6 seasons so far always first time) I am able to climb away at 500 or 600 ft per min. This has a real safety benefit over a Solo sustainer - that I am always within prop out glide range of the field over which I started up.

[Eric Greenwell[_4_]]

On 9/22/2012 10:55 PM, wrote:
> Dear gliderpilots!
>
> Manufacturers are not completely sure which is the way to go. So here
> you can vote for your favorite sustainer system:
>
> http://www.front-electric-sustainer.com/voting.php

Most pilots aren't knowledgeable about the attributes of all the
choices, so the voting might not be well informed. Because there are
significant differences between the types, I suggest you revise the page
to give the voters some realistic choices. For example, you could have a
table with these columns:

Engine type
Performance effects: Added weight and drag
Typical retrieve distance
Retrieve speed (cruise and sawtooth)
Ease of use
Reliability (failure to start rate)
Costs: Purchase price and maintenance

Personally, I want the sustainer with the simplicity of the FES, the
high speed of the jet, and the distance obtained by the petrol engine!

Kidding aside, I think most glider pilots would find their enjoyment of
soaring quite enhanced by a sustainer that provided as little as 3000
feet of climb. I think most landouts could be avoided with that much
"reserve", and it would give pilots the confidence to fly more often and
fly further.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

[[email protected]]

> Most pilots aren't knowledgeable about the attributes of all the
>
> choices, so the voting might not be well informed. Because there are
>
> significant differences between the types, I suggest you revise the page
>
> to give the voters some realistic choices. For example, you could have a
>
> table with these columns:
>
>
>
> Engine type
>
> Performance effects: Added weight and drag
>
> Typical retrieve distance
>
> Retrieve speed (cruise and sawtooth)
>
> Ease of use
>
> Reliability (failure to start rate)
>
> Costs: Purchase price and maintenance
>
>
>
> Personally, I want the sustainer with the simplicity of the FES, the
>
> high speed of the jet, and the distance obtained by the petrol engine!
>
>
>
> Kidding aside, I think most glider pilots would find their enjoyment of
>
> soaring quite enhanced by a sustainer that provided as little as 3000
>
> feet of climb. I think most landouts could be avoided with that much
>
> "reserve", and it would give pilots the confidence to fly more often and
>
> fly further.
>
>
>
> --
>
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>
> email me)

Dear Eric,

Your comments are appreciated, but I can not do such a table as it could be biased. Such comparison table would become probbably too complicated as there are too many factors which need to be taken in account to have fair comparison.
Actually I would like to see the result with existing knowledge of pilots.
Just too see in which way pilots are thinking...

[John Cochrane[_3_]]

>
> Kidding aside, I think most glider pilots would find their enjoyment of
> soaring quite enhanced by a sustainer that provided as little as 3000
> feet of climb. I think most landouts could be avoided with that much
> "reserve", and it would give pilots the confidence to fly more often and
> fly further.
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
> email me)

3000 feet of climb would do it for me -- especially if "instant on"
like the FES, no drag (sorry, serious competitions), light weight (a
big issue. I like to climb in weak lift, not turn on the motor!) and
little maintenance. For almost all contest flying 3000' gets you to
an airport if it does not get you home.

From an engineering standpoint, I don't really see why the electrics
don't also charge the battery. If you climb to 3000', in 20 minutes,
surely running the prop in generator mode for 20 minutes or so,
doubling your sink rate temporarily, should recharge the batteries?
This could make a 3000' capacity enough for self launch and
retrieve!.

John Cochrane

[Eric Greenwell[_4_]]

On 9/23/2012 10:07 AM, wrote:
> Your comments are appreciated, but I can not do such a table as it
> could be biased. Such comparison table would become probbably too
> complicated as there are too many factors which need to be taken in
> account to have fair comparison. Actually I would like to see the
> result with existing knowledge of pilots. Just too see in which way
> pilots are thinking...

This survey is not a sales pitch, and people will not choose what to buy
based on what's in the table. It's to your advantage to keep the table
as realistic as possible, so you have an idea of what the pilots really
want.

If people do not understand the tradeoffs between the three methods,
they will vote for something that they will not want to buy. At the very
least, the choices should include weight, gliding performance penalty,
retrieve distance, and purchase cost. Adequate numbers are available for
these attributes. A range of values could be shown, if a single value
isn't good enough.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

[Eric Greenwell[_4_]]

On 9/23/2012 10:16 AM, John Cochrane wrote:
> From an engineering standpoint, I don't really see why the electrics
> don't also charge the battery. If you climb to 3000', in 20 minutes,
> surely running the prop in generator mode for 20 minutes or so,
> doubling your sink rate temporarily, should recharge the batteries?
> This could make a 3000' capacity enough for self launch and
> retrieve!.

I haven't heard a designer discuss this, but it is intriguing. My guess
is the cost and the complexity are great enough, it's a better tradeoff
to increase the battery size from a 3000' climb capacity to a 5000'
climb capacity, so you still have 3000' left after a self-launch. The
Silent and similar electric gliders have about that climb capacity; in
fact, I think they allow you to choose the climb capacity by buying
additional battery packs.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

[[email protected]]

Dne nedelja, 23. september 2012 20:01:53 UTC+2 je oseba Eric Greenwell napisala:
> On 9/23/2012 10:16 AM, John Cochrane wrote:
>
> > From an engineering standpoint, I don't really see why the electrics
>
> > don't also charge the battery. If you climb to 3000', in 20 minutes,
>
> > surely running the prop in generator mode for 20 minutes or so,
>
> > doubling your sink rate temporarily, should recharge the batteries?
>
> > This could make a 3000' capacity enough for self launch and
>
> > retrieve!.
>
>
>
> I haven't heard a designer discuss this, but it is intriguing. My guess
>
> is the cost and the complexity are great enough, it's a better tradeoff
>
> to increase the battery size from a 3000' climb capacity to a 5000'
>
> climb capacity, so you still have 3000' left after a self-launch. The
>
> Silent and similar electric gliders have about that climb capacity; in
>
> fact, I think they allow you to choose the climb capacity by buying
>
> additional battery packs.
>
>
>
> --
>
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>
> email me)

Vote is between sustainers, not including selflaunching systems! Sustainers have all very similar weight, and also pricing. The difference is in mainly in range, noise, operation, maintenance etc.

Just a few comments:
1.Manufacturers would like to produce what they will be able to sell, but is not obvious what pilots will choose. So that is the reason of this voting!
2.Using prop in regenerative way is not really efficient (maybe 5%) due to wrong airfoil curvature for this mode.
3.At Silent Electro (FES) is not possible to chose between two different packs, as this would change CG position and also total voltage of cells, and caused some additional problems. Silent can climb about 6500' with only 30kg of batteries which is more than enough. Adding more batteries would be just more costs and more weight.

Regards,

Luka Znidarsic, designer of FES system

[Greg Arnold]

On 9/23/2012 12:00 PM, wrote:

>
> Vote is between sustainers, not including selflaunching systems! Sustainers have all very similar weight, and also pricing. The difference is in mainly in range, noise, operation, maintenance etc.
>
> Just a few comments:
> 1.Manufacturers would like to produce what they will be able to sell, but is not obvious what pilots will choose. So that is the reason of this voting!
> 2.Using prop in regenerative way is not really efficient (maybe 5%) due to wrong airfoil curvature for this mode.
> 3.At Silent Electro (FES) is not possible to chose between two different packs, as this would change CG position and also total voltage

of cells, and caused some additional problems. Silent can climb about
6500' with only 30kg of batteries which is more than enough.


To what altitude can the LAK climb?


Adding more batteries would be just more costs and more weight.
>
> Regards,
>
> Luka Znidarsic, designer of FES system
>

[Eric Greenwell[_4_]]

On 9/23/2012 12:00 PM, wrote:
> 3.At Silent Electro (FES) is not possible to chose between two
> different packs, as this would change CG position and also total
> voltage of cells, and caused some additional problems. Silent can
> climb about 6500' with only 30kg of batteries which is more than
> enough. Adding more batteries would be just more costs and more
> weight.

I see the Silent models have changed a bit from the last time I looked,
now with the FES version, which has much more climb capacity the older
electric versions. 6500' is plenty for self-launching and a long
self-retrieve. It would be enough to get most pilots home, and almost
everyone to at least an airport!

I've added the FES site to the "Dealer Contacts" list on the
Auxiliary-powered Sailplane Association site (http://motorglider.org).

Apparently, I misunderstood the purpose of the two battery packs in the
FES Lak 17 that was at the SSA convention earlier this year. You need
both, as Luka points out.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

[[email protected]]

Thank you for adding FES to Dealers Contact at ASA webpage!

There are two packs for a few reasons:
-at FES batteries are charged outside of glider, so with two packs weigh of one pack is only 15kg, which is still acceptable for holding them in hands.
-Voltage of one fully charged pack is 58V which is safe enough for hadling.

Regards,

Luka

[waremark]

On Monday, September 24, 2012 8:51:33 AM UTC+1, wrote:
> Thank you for adding FES to Dealers Contact at ASA webpage!
>
>
>
> There are two packs for a few reasons:
>
> -at FES batteries are charged outside of glider, so with two packs weigh of one pack is only 15kg, which is still acceptable for holding them in hands.
>
> -Voltage of one fully charged pack is 58V which is safe enough for hadling.
>
>
>
> Regards,
>
>
>
> Luka

Luka, I don't see why you cannot give at least a large part of the information which I or Eric requested. By all means use manufacturer quoted information for the rival products. I must say if I was in the market for a sustainer I would be looking for such information.

I have worked out from the FES website that for the FES system you claim 45 kg weight, no increase in drag (can that really be true? - many people would find that really important), 5,000 foot of climb, and 3 knots rate of climb. The only new 15m plus glider available with the system is the LAK 17 15/18, but you say the system is technically suitable for retro-fitting to a wide range of gliders. Have I got all that right?

[Greg Arnold]

On 9/24/2012 1:57 PM, waremark wrote:
> On Monday, September 24, 2012 8:51:33 AM UTC+1, wrote:
> Luka, I don't see why you cannot give at least a large part of the
> information which I or Eric requested. By all means use manufacturer
> quoted information for the rival products. I must say if I was in the
> market for a sustainer I would be looking for such information. I have
> worked out from the FES website that for the FES system you claim 45
> kg weight, no increase in drag (can that really be true? - many people
> would find that really important), 5,000 foot of climb, and 3 knots
> rate of climb. The only new 15m plus glider available with the system
> is the LAK 17 15/18, but you say the system is technically suitable
> for retro-fitting to a wide range of gliders. Have I got all that right?

Even if Luka doesn't put info about his competition on his webpage, it
would help if he could at least put info about his own product in an
easily read and easily found table.

Or get Paul Remde on board as his US representative!

[Renny[_2_]]

On Monday, September 24, 2012 3:56:17 PM UTC-6, Greg Arnold wrote:
> On 9/24/2012 1:57 PM, waremark wrote:
>
> > On Monday, September 24, 2012 8:51:33 AM UTC+1, wrote:
>
> > Luka, I don't see why you cannot give at least a large part of the
>
> > information which I or Eric requested. By all means use manufacturer
>
> > quoted information for the rival products. I must say if I was in the
>
> > market for a sustainer I would be looking for such information. I have
>
> > worked out from the FES website that for the FES system you claim 45
>
> > kg weight, no increase in drag (can that really be true? - many people
>
> > would find that really important), 5,000 foot of climb, and 3 knots
>
> > rate of climb. The only new 15m plus glider available with the system
>
> > is the LAK 17 15/18, but you say the system is technically suitable
>
> > for retro-fitting to a wide range of gliders. Have I got all that right?
>
>
>
> Even if Luka doesn't put info about his competition on his webpage, it
>
> would help if he could at least put info about his own product in an
>
> easily read and easily found table.
>
>
>
> Or get Paul Remde on board as his US representative!

Here's the URL for a PDF brochure that was handed out at the 2012 Reno Convention on the FES. Hopefully, it will answer some of the many questions that are out there!

http://www.front-electric-sustainer.com/PDF%20Articles/FES_katalog_V2.pdf

Thanks - Renny

[Greg Arnold]

On 9/24/2012 3:39 PM, Renny wrote:

>
> Here's the URL for a PDF brochure that was handed out at the 2012 Reno Convention on the FES. Hopefully, it will answer some of the many questions that are out there!
>
> http://www.front-electric-sustainer.com/PDF%20Articles/FES_katalog_V2.pdf
>
> Thanks - Renny
>


Interesting that the Silent has more battery capacity than the LAK. I
wonder if the LAK can be modified to take the larger battery capacity.

[Renny[_2_]]

On Monday, September 24, 2012 4:53:12 PM UTC-6, Greg Arnold wrote:
> On 9/24/2012 3:39 PM, Renny wrote:
>
>
>
> >
>
> > Here's the URL for a PDF brochure that was handed out at the 2012 Reno Convention on the FES. Hopefully, it will answer some of the many questions that are out there!
>
> >
>
> > http://www.front-electric-sustainer.com/PDF%20Articles/FES_katalog_V2.pdf
>
> >
>
> > Thanks - Renny
>
> >
>
>
>
>
>
> Interesting that the Silent has more battery capacity than the LAK. I
>
> wonder if the LAK can be modified to take the larger battery capacity.

Greg,
My LAK-17B FES does have two batteries with 14 cells...so it does have the following:

"2 x 14S LiPo, 20 kW continuous power"

The earlier installations had the 12 cell LiPo batteries, but it was upped to 14 cells for the newer 17B installations. Each battery is 58 volts, so when fully charged it starts off at 116 volts. FYI, I did write an article for Soaring on the LAK-17B FES and I am hopeful that it will be published soon.

Thx - Renny

[Greg Arnold]

On 9/24/2012 4:23 PM, Renny wrote:

>>
>> Interesting that the Silent has more battery capacity than the LAK. I
>>
>> wonder if the LAK can be modified to take the larger battery capacity.
>
> Greg,
> My LAK-17B FES does have two batteries with 14 cells...so it does have the following:
>
> "2 x 14S LiPo, 20 kW continuous power"
>
> The earlier installations had the 12 cell LiPo batteries, but it was upped to 14 cells for the newer 17B installations. Each battery is 58 volts, so when fully charged it starts off at 116 volts. FYI, I did write an article for Soaring on the LAK-17B FES and I am hopeful that it will be published soon.
>
> Thx - Renny
>

Renny:

What type of climb rate, total climb, and range are you seeing?

[Renny[_2_]]

On Monday, September 24, 2012 5:38:14 PM UTC-6, Greg Arnold wrote:
> On 9/24/2012 4:23 PM, Renny wrote:
>
>
>
> >>
>
> >> Interesting that the Silent has more battery capacity than the LAK. I
>
> >>
>
> >> wonder if the LAK can be modified to take the larger battery capacity.
>
> >
>
> > Greg,
>
> > My LAK-17B FES does have two batteries with 14 cells...so it does have the following:
>
> >
>
> > "2 x 14S LiPo, 20 kW continuous power"
>
> >
>
> > The earlier installations had the 12 cell LiPo batteries, but it was upped to 14 cells for the newer 17B installations. Each battery is 58 volts, so when fully charged it starts off at 116 volts. FYI, I did write an article for Soaring on the LAK-17B FES and I am hopeful that it will be published soon.
>
> >
>
> > Thx - Renny
>
> >
>
>
>
> Renny:
>
>
>
> What type of climb rate, total climb, and range are you seeing?

I have had limited experience running the FES on the LAK-17B FES as this is my first season using the FES and the ship was also away for several weeks this summer at the WGC in Uvalde. I am also very fortunate to fly out of Moriarty, and with our excellent conditions, I have not had to use it (thus far)out of necessity.

So, I have no data on endurance and range, but in conducting some local (unscientific) testing, I have been able to climb (dry) on a hot day (over 95 deg F on the ground) at over 200 fpm at altitudes of 8,500 to 9,000 feet MSL in the 18m configuration. FYI, the Moriarty airport is at 6,200 feet. Hopefully, you will see additional and more scientific data as Idaflieg testing was conducted in August and results are expected this winter.
Thx - Renny

[Eric Greenwell[_4_]]

On 9/24/2012 7:31 PM, Renny wrote:
> I have had limited experience running the FES on the LAK-17B FES as
> this is my first season using the FES and the ship was also away for
> several weeks this summer at the WGC in Uvalde. I am also very
> fortunate to fly out of Moriarty, and with our excellent conditions,
> I have not had to use it (thus far)out of necessity.

Next year, you should press a little harder, and get some value out the
FES. Then, you will discover it can set you free to explore more than
you imagine now!

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

[Renny[_2_]]

On Monday, September 24, 2012 9:04:19 PM UTC-6, Eric Greenwell wrote:
> On 9/24/2012 7:31 PM, Renny wrote:
>
> > I have had limited experience running the FES on the LAK-17B FES as
>
> > this is my first season using the FES and the ship was also away for
>
> > several weeks this summer at the WGC in Uvalde. I am also very
>
> > fortunate to fly out of Moriarty, and with our excellent conditions,
>
> > I have not had to use it (thus far)out of necessity.
>
>
>
> Next year, you should press a little harder, and get some value out the
>
> FES. Then, you will discover it can set you free to explore more than
>
> you imagine now!
>
>
>
> --
>
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>
> email me)

Eric,
Indeed...That is definitely the plan!
Thx - Renny

[bumper[_4_]]

On Sunday, September 23, 2012 10:16:30 AM UTC-7, John Cochrane wrote:
>

>
> From an engineering standpoint, I don't really see why the electrics
>
> don't also charge the battery. If you climb to 3000', in 20 minutes,
>
> surely running the prop in generator mode for 20 minutes or so,
>
> doubling your sink rate temporarily, should recharge the batteries?
>
> This could make a 3000' capacity enough for self launch and
>
> retrieve!.
>
>
>
> John Cochrane

John,

I'm not an engineer by any stretch, but your question seems to presume 100% effeciency. Even under ideal circumstances propellers are closer to 80% - - so that would be at least a 20% loss on both discharge and charge.

Then there's the heat loss due to friction and resistance of leads and internal motor windings. Couple that with battery heat generation and loss due to internal resistance and chemical processes on both charge and discharge. All this may have one pointing downhill charging batteries for longer than might be comfortable. I get uncomfortable just thinking about it (g).

bumper
ASH26E . . . like those old Mazda commercials, Wankel engine go MMMMMMMMMMMMM!

[Craig Funston[_2_]]

On Saturday, September 22, 2012 10:55:27 PM UTC-7, wrote:
> Dear gliderpilots!
>
>
>
> Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system:
>
>
>
> http://www.front-electric-sustainer.com/voting.php
>
>
>
> Thank you,
>
>
>
> Luka

Regenerative energy derivation from soaring flight has actually been looked at fairly seriously. This is an interesting read on the subject
esoaring.com/regensoaring.pdf

Craig

[Tim Mara]

For performance, low weight, LOW drag, simplicity and safety. JET!
More manufacturers are developing or exploring Jet sustainers. Quite simply
the lack of moving parts, the very low weight to power output and when
properly configured to have the computer take the pilot out of decision
making of the actual operation of the engine the reliability of operation
make the Jet the best possible solution. The HpH 304 Jet doesn't require
massive, heavy and possibly hazardous batteries, doesn't require start-up
and operation or typical reciprocating engines, no priming, no chocking,
decompressing or diving to windmill and engine to start, no high parasitic
drag (the jet engine expended has actually less drag than the landing gear
down), no wind milling propellers, and short time from switch on the switch
off and stored, literally seconds to start so even at low altitudes can be
operational in seconds and without the high drag of a propeller is a non
issue when it might be necessary to glide the extra distance to make a safe
landing with an extended powerplant.
The Jet does have to be engineered right from the start and have systems
that are completely monitored and controlled by a computer system to take
the operator error possibility away and this is what has likely delayed the
release of the Jet sustainers from most manufacturers. Having flown just
about al types from simple 2 cycle ultra-lites to small corporate Jet
aircraft I can see potential issues with operators not fully trained in Jet
engine operation without the development of a computer based system to
control the operation of the jet engine. With the HpH system the controller
monitors all aspects of the engine from start-up to engine cool down and
stowage, it is simply refined ...
regards
tim
Please visit the Wings & Wheels website at www.wingsandwheels.com


> wrote in message
...
> Dear gliderpilots!
>
> Manufacturers are not completely sure which is the way to go. So here you
> can vote for your favorite sustainer system:
>
> http://www.front-electric-sustainer.com/voting.php
>
> Thank you,
>
> Luka

[Eric Greenwell[_4_]]

On 9/25/2012 7:21 AM, Tim Mara wrote:
> For performance, low weight, LOW drag, simplicity and safety. JET!
> More manufacturers are developing or exploring Jet sustainers. Quite simply
> the lack of moving parts, the very low weight to power output and when
> properly configured to have the computer take the pilot out of decision
> making of the actual operation of the engine the reliability of operation
> make the Jet the best possible solution. The HpH 304 Jet doesn't require
> massive, heavy and possibly hazardous batteries, doesn't require start-up
> and operation or typical reciprocating engines, no priming, no chocking,
> decompressing or diving to windmill and engine to start, no high parasitic
> drag (the jet engine expended has actually less drag than the landing gear
> down), no wind milling propellers, and short time from switch on the switch
> off and stored, literally seconds to start so even at low altitudes can be
> operational in seconds and without the high drag of a propeller is a non
> issue when it might be necessary to glide the extra distance to make a safe
> landing with an extended powerplant.
> The Jet does have to be engineered right from the start and have systems
> that are completely monitored and controlled by a computer system to take
> the operator error possibility away and this is what has likely delayed the
> release of the Jet sustainers from most manufacturers. Having flown just
> about al types from simple 2 cycle ultra-lites to small corporate Jet
> aircraft I can see potential issues with operators not fully trained in Jet
> engine operation without the development of a computer based system to
> control the operation of the jet engine. With the HpH system the controller
> monitors all aspects of the engine from start-up to engine cool down and
> stowage, it is simply refined ...
> regards

Tim makes some excellent points for the jet sustainer, but every one of
them also applies to the FES. Sure, it's got those "possibly hazardous
batteries", but it does not have those "possibly hazardous 8 gallons of
fuel".

This illustrates the problem with the current voting choices, offered
without any description of each systems attributes. Even a dealer does
not tell us the important differences between two of the three choices,
so how can the average "voter" make an informed choice?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

[[email protected]]

Dne nedelja, 23. september 2012 07:55:27 UTC+2 je oseba napisala:
> Dear gliderpilots!
>
>
>
> Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system:
>
>
>
> http://www.front-electric-sustainer.com/voting.php
>
>
>
> Thank you,
>
>
>
> Luka

[Chris Nicholas[_2_]]

I have a Lak 17A with FES. I had the glider already, so a retrofit
sustainer was the only option. I chose the FES for those features which are
undoubted advantages compared with an internal combustion engine/pylon. My
reasons and the outcome are set out in two articles which are available on
Luka’s website.

For somebody contemplating a new glider, or for a manufacturer
contemplating choices between one route and another, I think there are a
number of unknowns. These include the reliability in starting in the air,
general reliability, relative safety, hazard warning, longevity, ongoing
maintenance costs, battery replacement costs, etc..

My personal opinion, based on very limited numbers of FES and jet, but
rather larger numbers of internal combustion engines, is that:

FES reliability is unproven, but I have no reason to think that it will be
anything other than good. I have a friend with a Lak with a sustainer
engine who has landed out several times after it failed to start in the
air, with of course a considerably higher decision than the FES needs. The
jet is claimed to have a low decision height and quick start up, but I have
heard of one user who is onto his third engine which does not sound like
good reliability to me, if true. I have no idea whether the jet is close to
100% reliable starting in the air.

Lipo batteries based on model aircraft flying and some other applications
have a reputation for occasional disastrous fires. The FES system has
temperature sensors and warnings which give me some comfort. I have a
photograph of fire damage caused to a glider with an internal combustion
engine. The pilot did not know until he was landing or had landed that it
was destroying the fuselage behind the wing. He was very lucky he was not
cruising high at the time. I suspect that the jet has too little service as
yet for anyone to know whether it is better or worse.

FES Battery replacement costs are likely to be 200-500 units of currency a
year on average, maybe less. Electric motors are usually very reliable. I
don’t know about the control system. My friend with the internal
combustion engine is having cracking problems with his exhaust system.
Others have too. I don’t know what other routine or sporadic maintenance
costs are involved. I don’t suppose anyone can say what they will be for
the jet, although for someone to be on his third motor is not an
encouraging sign.

I’m certainly very happy with my decision. The range is okay, as an early
adopter I don’t have some of the features now available, but it was the
right decision for me at the time. For other people, and in the future,
there may be good reasons for different choices. In my opinion, nobody can
yet know.

Chris N

[[email protected]]

> To what altitude can the LAK climb?

LAK17A FES can climb about 1500m
LAK17B FES can climb 1250m

Regards,

Luka

[Dan Marotta]

In the US, the FAA required a type rating for any turbine-powered aircraft.
Lately, it seems, they now a Letter of Authorization, to fly a jet powered
glider. This letter must be renewed annually with a checkride. Seems a bit
extreme for me.

Note: My information about the jet glider comes from an acquaintance who
just checked out in the Bonus Jet self-launch glider based at Moriarty, NM.


"Chris Nicholas" > wrote in message
...
>I have a Lak 17A with FES. I had the glider already, so a retrofit
> sustainer was the only option. I chose the FES for those features which
> are
> undoubted advantages compared with an internal combustion engine/pylon. My
> reasons and the outcome are set out in two articles which are available on
> Lukaâ?Ts website.
>
> For somebody contemplating a new glider, or for a manufacturer
> contemplating choices between one route and another, I think there are a
> number of unknowns. These include the reliability in starting in the air,
> general reliability, relative safety, hazard warning, longevity, ongoing
> maintenance costs, battery replacement costs, etc..
>
> My personal opinion, based on very limited numbers of FES and jet, but
> rather larger numbers of internal combustion engines, is that:
>
> FES reliability is unproven, but I have no reason to think that it will be
> anything other than good. I have a friend with a Lak with a sustainer
> engine who has landed out several times after it failed to start in the
> air, with of course a considerably higher decision than the FES needs. The
> jet is claimed to have a low decision height and quick start up, but I
> have
> heard of one user who is onto his third engine which does not sound like
> good reliability to me, if true. I have no idea whether the jet is close
> to
> 100% reliable starting in the air.
>
> Lipo batteries based on model aircraft flying and some other applications
> have a reputation for occasional disastrous fires. The FES system has
> temperature sensors and warnings which give me some comfort. I have a
> photograph of fire damage caused to a glider with an internal combustion
> engine. The pilot did not know until he was landing or had landed that it
> was destroying the fuselage behind the wing. He was very lucky he was not
> cruising high at the time. I suspect that the jet has too little service
> as
> yet for anyone to know whether it is better or worse.
>
> FES Battery replacement costs are likely to be 200-500 units of currency a
> year on average, maybe less. Electric motors are usually very reliable. I
> donâ?Tt know about the control system. My friend with the internal
> combustion engine is having cracking problems with his exhaust system.
> Others have too. I donâ?Tt know what other routine or sporadic maintenance
> costs are involved. I donâ?Tt suppose anyone can say what they will be for
> the jet, although for someone to be on his third motor is not an
> encouraging sign.
>
> Iâ?Tm certainly very happy with my decision. The range is okay, as an
> early
> adopter I donâ?Tt have some of the features now available, but it was the
> right decision for me at the time. For other people, and in the future,
> there may be good reasons for different choices. In my opinion, nobody can
> yet know.
>
> Chris N
>
>
>

[[email protected]]

Dne torek, 25. september 2012 18:00:15 UTC+2 je oseba Eric Greenwell napisala:
> On 9/25/2012 7:21 AM, Tim Mara wrote:
>
> > For performance, low weight, LOW drag, simplicity and safety. JET!
>
> > More manufacturers are developing or exploring Jet sustainers. Quite simply
>
> > the lack of moving parts, the very low weight to power output and when
>
> > properly configured to have the computer take the pilot out of decision
>
> > making of the actual operation of the engine the reliability of operation
>
> > make the Jet the best possible solution. The HpH 304 Jet doesn't require
>
> > massive, heavy and possibly hazardous batteries, doesn't require start-up
>
> > and operation or typical reciprocating engines, no priming, no chocking,
>
> > decompressing or diving to windmill and engine to start, no high parasitic
>
> > drag (the jet engine expended has actually less drag than the landing gear
>
> > down), no wind milling propellers, and short time from switch on the switch
>
> > off and stored, literally seconds to start so even at low altitudes can be
>
> > operational in seconds and without the high drag of a propeller is a non
>
> > issue when it might be necessary to glide the extra distance to make a safe
>
> > landing with an extended powerplant.
>
> > The Jet does have to be engineered right from the start and have systems
>
> > that are completely monitored and controlled by a computer system to take
>
> > the operator error possibility away and this is what has likely delayed the
>
> > release of the Jet sustainers from most manufacturers. Having flown just
>
> > about al types from simple 2 cycle ultra-lites to small corporate Jet
>
> > aircraft I can see potential issues with operators not fully trained in Jet
>
> > engine operation without the development of a computer based system to
>
> > control the operation of the jet engine. With the HpH system the controller
>
> > monitors all aspects of the engine from start-up to engine cool down and
>
> > stowage, it is simply refined ...
>
> > regards
>
>
>
> Tim makes some excellent points for the jet sustainer, but every one of
>
> them also applies to the FES. Sure, it's got those "possibly hazardous
>
> batteries", but it does not have those "possibly hazardous 8 gallons of
>
> fuel".
>
>
>
> This illustrates the problem with the current voting choices, offered
>
> without any description of each systems attributes. Even a dealer does
>
> not tell us the important differences between two of the three choices,
>
> so how can the average "voter" make an informed choice?
>
>
>
> --
>
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>
> email me)


I will write here just a few attributes of the FES which I think are the most important:

-reliable start, full power available in 1s, switching off also very quick
-no smell in cockpit, no oil on fuselage
-small noise outside and inside of cockpit
-low vibrations
-good max climb rate about 2,5m/s at 22kW for LAK17A (depend on weigh of glider)
-very efficient system (only 4kW of power is neccesery for horizontal flight) which gives about 100km of range
-big advantage is that 12V power is available from main baterie pack, (DC/DC converter) so you have finally enough power for Radio, Transponder, PDA, Vario etc, acctually for the whole flying season
-all 12V Pb batteries can be removed (this mean usually minus 5kg)
-only about 50kg of additional weigh - 5kg of Pb= 45kg
-no change of drag or CG position during engine run
-according Idaflieg test results, drag of propeller blades is really minimal (official results published in winter)
-very chaep charging of batteries, outside of glider
-virtually maintenance-free
-price in range of Solo sustainers

Articles about FES:
http://www.front-electric-sustainer.com/articles.php

Very good article about recent JETs:
http://www.psr-jet-system.com/___010_content_EN/___030_Download/20120116_-_The_Turbine_-_better_than_its_reputation_-_Segelfliegen.pdf

There is not much about Solo sustainers but here is one:
http://www.trb.8m.com/

So now is up to you to take some time to read and decide which one you would choose!

Regards,

Luka

[[email protected]]

I will write here just a few attributes of the FES which I think are the most important:
>
>
>
> -reliable start, full power available in 1s, switching off also very quick
>
> -no smell in cockpit, no oil on fuselage
>
> -small noise outside and inside of cockpit
>
> -low vibrations
>
> -good max climb rate about 2,5m/s at 22kW for LAK17A (depend on weigh of glider)
>
> -very efficient system (only 4kW of power is neccesery for horizontal flight) which gives about 100km of range
>
> -big advantage is that 12V power is available from main baterie pack, (DC/DC converter) so you have finally enough power for Radio, Transponder, PDA, Vario etc, acctually for the whole flying season
>
> -all 12V Pb batteries can be removed (this mean usually minus 5kg)
>
> -only about 50kg of additional weigh - 5kg of Pb= 45kg
>
> -no change of drag or CG position during engine run
>
> -according Idaflieg test results, drag of propeller blades is really minimal (official results published in winter)
>
> -very chaep charging of batteries, outside of glider
>
> -virtually maintenance-free
>
> -price in range of Solo sustainers
>


As there was a lot of votes today for JET (I think good article on link above helps) I think I need to lighten some more advantages of FES:

-Light gliders like Silent, AS13.5, Apis becomes with FES real selflaunchers with comparable or even better climb rates than if equiped with combustion retractable engines.

-Even when FES is installed on 18m glider, max climb rate is much better than it is achived with JET or Solo.

-As it is slower than JET you do not pass thermals too quickly, but you can do some turns to center (under power or even without, at normal thermaling speeds) and preserve energy. Actually is it suprising how much energy is even in weak thermals.

-You can use it in mountains, on the ridge to help you climb above the peaks. Even that you have motor you still feel it as soaring, so not bad feling...

-FES is possible to use even in horizontal flight trough (not too heavy) rain (ventlation is prefared to be closed) without fear to damage proppeller blades up to about 3500 RPM.

-Only at FES start is instant, so it can save you out of unladable valleys.

Regards,

Luka

[[email protected]]

For me electrical sustainer in a glider is the perfect solution. It links in to the spirit of the sport, beter than a turbine. But the propellor on the nose feels slightly off.... Especially when you consider the bugwipergarages becoming standard on the topsailplanes. We are spending more and more on reducing drag. Then this minor addition feels going against the flow. Why not a small pilon whit this nice foldable propellor you have engineered? Or am I the only one who has this uncomfortable feeling?

Secondly adding 45 kg to the non- lifting parts is a bit of a stretch. I contacted a manufacturer who was very kind to talk more than 30 minutes on the subject. But changing this limit on existing planes seems very far fetched. Any news in this area?

Marco

[Andrzej Kobus]

On Sep 26, 6:06*pm, wrote:
> For me electrical sustainer in a glider is the perfect solution. It links in to the spirit of the sport, beter than a turbine. But the propellor on the nose feels slightly off.... Especially when you consider the bugwipergarages becoming standard on the topsailplanes. We are spending more and more on reducing drag. Then this minor addition feels going against the flow. Why not a small pilon whit this nice foldable propellor you have engineered? Or am I the only one who has this uncomfortable feeling?
>
> Secondly adding 45 kg to the non- lifting parts is a bit of a stretch. I contacted a manufacturer who was very kind to talk more than 30 minutes on the subject. But changing this limit on existing planes seems very far fetched. Any news in this area?
>
> Marco

I also have an issue with modification to the front of the fuselage
where the tow hook is (at least in my glider) and another point is
that this is an important area not to be tempered with in crash
resistant cockpits. I have no problems with the added weight due to my
good eating habits :).

[Chris Davison[_2_]]

Think of this in terms of cars, would you rather have an electric car or a
jet
car?? Every pilot out there secretly wants to be a jet pilot...

Benefits? Who cares!

My vote goes for the first technology that can be fitted to a Libelle!

Chris



At 20:33 25 September 2012, wrote:
>Dne torek, 25. september 2012 18:00:15 UTC+2 je oseba Eric Greenwell
>napisala:
>> On 9/25/2012 7:21 AM, Tim Mara wrote:
>>
>> > For performance, low weight, LOW drag, simplicity and safety. JET!
>>
>> > More manufacturers are developing or exploring Jet sustainers. Quite
>simply
>>
>> > the lack of moving parts, the very low weight to power output and
when
>>
>> > properly configured to have the computer take the pilot out of
decision
>>
>> > making of the actual operation of the engine the reliability of
>operation
>>
>> > make the Jet the best possible solution. The HpH 304 Jet doesn't
>require
>>
>> > massive, heavy and possibly hazardous batteries, doesn't require
>start-up
>>
>> > and operation or typical reciprocating engines, no priming, no
>chocking,
>>
>> > decompressing or diving to windmill and engine to start, no high
>parasitic
>>
>> > drag (the jet engine expended has actually less drag than the landing
>gear
>>
>> > down), no wind milling propellers, and short time from switch on the
>switch
>>
>> > off and stored, literally seconds to start so even at low altitudes
can
>be
>>
>> > operational in seconds and without the high drag of a propeller is a
>non
>>
>> > issue when it might be necessary to glide the extra distance to make
a
>safe
>>
>> > landing with an extended powerplant.
>>
>> > The Jet does have to be engineered right from the start and have
>systems
>>
>> > that are completely monitored and controlled by a computer system to
>take
>>
>> > the operator error possibility away and this is what has likely
delayed
>the
>>
>> > release of the Jet sustainers from most manufacturers. Having flown
>just
>>
>> > about al types from simple 2 cycle ultra-lites to small corporate Jet
>>
>> > aircraft I can see potential issues with operators not fully trained
in
>Jet
>>
>> > engine operation without the development of a computer based system
to
>>
>> > control the operation of the jet engine. With the HpH system the
>controller
>>
>> > monitors all aspects of the engine from start-up to engine cool down
>and
>>
>> > stowage, it is simply refined ...
>>
>> > regards
>>
>>
>>
>> Tim makes some excellent points for the jet sustainer, but every one of

>>
>> them also applies to the FES. Sure, it's got those "possibly hazardous
>>
>> batteries", but it does not have those "possibly hazardous 8 gallons of

>>
>> fuel".
>>
>>
>>
>> This illustrates the problem with the current voting choices, offered
>>
>> without any description of each systems attributes. Even a dealer does
>>
>> not tell us the important differences between two of the three choices,

>>
>> so how can the average "voter" make an informed choice?
>>
>>
>>
>> --
>>
>> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
>>
>> email me)
>
>
>I will write here just a few attributes of the FES which I think are the
>most important:
>
>-reliable start, full power available in 1s, switching off also very
quick
>-no smell in cockpit, no oil on fuselage
>-small noise outside and inside of cockpit
>-low vibrations
>-good max climb rate about 2,5m/s at 22kW for LAK17A (depend on weigh
of
>glider)
>-very efficient system (only 4kW of power is neccesery for horizontal
>flight) which gives about 100km of range
>-big advantage is that 12V power is available from main baterie pack,
>(DC/DC converter) so you have finally enough power for Radio,
Transponder,
>PDA, Vario etc, acctually for the whole flying season
>-all 12V Pb batteries can be removed (this mean usually minus 5kg)
>-only about 50kg of additional weigh - 5kg of Pb= 45kg
>-no change of drag or CG position during engine run
>-according Idaflieg test results, drag of propeller blades is really
>minimal (official results published in winter)
>-very chaep charging of batteries, outside of glider
>-virtually maintenance-free
>-price in range of Solo sustainers
>
>Articles about FES:
>http://www.front-electric-sustainer.com/articles.php
>
>Very good article about recent JETs:
>http://www.psr-jet-
system.com/___010_content_EN/___030_Download/20120116_-
_The_Turbine_-_better_than_its_reputation_-_Segelfliegen.pdf
>
>There is not much about Solo sustainers but here is one:
>http://www.trb.8m.com/
>
>So now is up to you to take some time to read and decide which one you
>would choose!
>
>Regards,
>
>Luka
>

[waremark]

On Thursday, September 27, 2012 12:00:04 AM UTC+1, Chris Davison wrote:

> My vote goes for the first technology that can be fitted to a Libelle!
>

And I only want a system which can provide enough power to self-launch an 18m or larger glider, and have sufficient power left for a relight and/or a long retrieve. Which today means a combustion engine.

But I have to say that if I did not want self-launch, either the FES or the Jet would seem overwhelmingly better than the Turbo. For me it would be the jet because I don't like the idea of even a little drag from the prop, and I feel uneasy about having a mechanism in front of my feet - but it would have to be a jet which gives a good rate of climb, which if I understood correctly pretty much means a JS1 or an HP304.

[[email protected]]

Dne �etrtek, 27. september 2012 02:07:47 UTC+2 je oseba waremark napisala:
> On Thursday, September 27, 2012 12:00:04 AM UTC+1, Chris Davison wrote:
>
>
>
> > My vote goes for the first technology that can be fitted to a Libelle!
>
> >
>
>
>
> And I only want a system which can provide enough power to self-launch an 18m or larger glider, and have sufficient power left for a relight and/or a long retrieve. Which today means a combustion engine.
>
>
>
> But I have to say that if I did not want self-launch, either the FES or the Jet would seem overwhelmingly better than the Turbo. For me it would be the jet because I don't like the idea of even a little drag from the prop, and I feel uneasy about having a mechanism in front of my feet - but it would have to be a jet which gives a good rate of climb, which if I understood correctly pretty much means a JS1 or an HP304.


Video of LAK17A FES takeoff using 120m of rope and Auto tow.

http://www.youtube.com/watch?v=pTeNKM2cXQk&feature=player_embedded

[RW[_2_]]

Luka,
Many of US glider ports have 4-5000ft paved runway.
Do you think electric scooter hub motor would help FES launch
850lbs Standard glider ?
Do you think , you could change shape of the batteries so we can slip
them in the wings instead of water bags ?
With Chinese batteries prices dropping down,and most of US gliders registered experimental,do you think you could sell FES kits for $15000 if you have at least 100 customers ?
In US most of us are keeping gliders in the trailer, and trailer sits outdoors,did you think about creating solar charging system for FES batteries on the trailer ?
Ryszard

[[email protected]]

On Monday, September 24, 2012 4:23:59 PM UTC-7, Renny wrote:
> On Monday, September 24, 2012 4:53:12 PM UTC-6, Greg Arnold wrote: > On 9/24/2012 3:39 PM, Renny wrote: > > > > > > > > Here's the URL for a PDF brochure that was handed out at the 2012 Reno Convention on the FES. Hopefully,

Renny, so you're running about 170 Amps or so. Your motor and esc need some cooling, so how is that accomplished? And then you must have a way to automatically override throttle if lipos approach 70 to 80% drained?

[Renny[_2_]]

On Friday, September 28, 2012 6:00:43 PM UTC-6, (unknown) wrote:
> On Monday, September 24, 2012 4:23:59 PM UTC-7, Renny wrote:
>
> > On Monday, September 24, 2012 4:53:12 PM UTC-6, Greg Arnold wrote: > On 9/24/2012 3:39 PM, Renny wrote: > > > > > > > > Here's the URL for a PDF brochure that was handed out at the 2012 Reno Convention on the FES. Hopefully,
>
>
>
> Renny, so you're running about 170 Amps or so. Your motor and esc need some cooling, so how is that accomplished? And then you must have a way to automatically override throttle if lipos approach 70 to 80% drained?

Motor cooling is handled via a small electric fan forward of the rudder pedals, an air vent in the nose cone that allows outside air to help cool the motor (and the cockpit), and 3 electric fans on the shelf behind the pilot's seat to cool the controller. When the batteries get low, warnings go off on the FCU, and I would then throttle back and turn off the FES. There is no automatic shutdown of the FES which allows the pilot to keep the FES running if there is an emergency situation. Thx - Renny

[[email protected]]

Here are my answers:

Dne petek, 28. september 2012 23:50:12 UTC+2 je oseba RW napisala:
> Luka,
>
> Many of US glider ports have 4-5000ft paved runway.
>
> Do you think electric scooter hub motor would help FES launch
>
> 850lbs Standard glider?

Now we have 22kW in front which is plenty of power for good acceleration on paved runway. Small enough motor which could fit into hub of Tost whell, I think could not have more than 1 or maybe 2kW.
You can see a video of LAK17A FES selflaunch at 400kg weight:

http://www.youtube.com/watch?v=3gLH946PPEU&feature=player_embedded

Even for selflaunch from a grass is enough power and we will also increase it in future. What is really neccesery for safe selflaunch from grass is slightly higher undercariange, which is also possible to achive, with some modifications.
And this is the plan to do it!

> Do you think , you could change shape of the batteries so we can slip
>
> them in the wings instead of water bags ?

Unfortunately this is not so simple. Check how batterie in the wings are arranged at Antares:
http://nadler.com/Antares/Antares_MechanicTraining.html

It can not be done in much different way, and so you need to have built in rails, to slide them in and so that they are fixed. Another issue is that wings are bending etc. On used glider all this would be science fiction...

> With Chinese batteries prices dropping down,and most of US gliders registered experimental,do you think you could sell FES kits for $15000 if you have at least 100 customers ?

Electric system must be properly installed, so we do not support selling kits, as we can not be sure that instalation would be done properly. There is only very little choice for suitable batteries (capacity, size, weight, and C ratings) which are still expensive. With bigger series I am sure price could drop considerably.

> In US most of us are keeping gliders in the trailer, and trailer sits outdoors,did you think about creating solar charging system for FES batteries on the trailer ?

This is possible and it was done already by solar and wind generators by other companyes, but it would higher the price, especially if there are buffer batteries in trailer like it was done at those solutions. To take batteries out and charging them on the grid is the cheapest and the safest way. But onyl at FES this is possible as there are only two 15kg batterie boxes, and they are easy to take out and install back. Storage of batteries is prefared at room temperatures. If trailer is standing on hot sun, than temperature inside is higher and this is not good for time life of batterie packs.


> Ryszard

[[email protected]]

Dne sobota, 29. september 2012 02:17:14 UTC+2 je oseba Renny napisala:
> On Friday, September 28, 2012 6:00:43 PM UTC-6, (unknown) wrote:
>
> > On Monday, September 24, 2012 4:23:59 PM UTC-7, Renny wrote:
>
> >
>
> > > On Monday, September 24, 2012 4:53:12 PM UTC-6, Greg Arnold wrote: > On 9/24/2012 3:39 PM, Renny wrote: > > > > > > > > Here's the URL for a PDF brochure that was handed out at the 2012 Reno Convention on the FES. Hopefully,
>
> >
>
> >
>
> >
>
> > Renny, so you're running about 170 Amps or so. Your motor and esc need some cooling, so how is that accomplished? And then you must have a way to automatically override throttle if lipos approach 70 to 80% drained?
>
>
>
> Motor cooling is handled via a small electric fan forward of the rudder pedals, an air vent in the nose cone that allows outside air to help cool the motor (and the cockpit), and 3 electric fans on the shelf behind the pilot's seat to cool the controller. When the batteries get low, warnings go off on the FCU, and I would then throttle back and turn off the FES. There is no automatic shutdown of the FES which allows the pilot to keep the FES running if there is an emergency situation. Thx - Renny

On our latest instalations, we manage to arrange cooling also without electric fan infront of pedals. Motor itself has bigger centrifugal ventilator at back side!

Regards, Luka

[slbair]

On Saturday, September 29, 2012 1:41:13 AM UTC-5, wrote:
> Dne sobota, 29. september 2012 02:17:14 UTC+2 je oseba Renny napisala:
>
> > On Friday, September 28, 2012 6:00:43 PM UTC-6, (unknown) wrote:
>
> >
>
> > > On Monday, September 24, 2012 4:23:59 PM UTC-7, Renny wrote:
>
> >
>
> > >
>
> >
>
> > > > On Monday, September 24, 2012 4:53:12 PM UTC-6, Greg Arnold wrote: > On 9/24/2012 3:39 PM, Renny wrote: > > > > > > > > Here's the URL for a PDF brochure that was handed out at the 2012 Reno Convention on the FES. Hopefully,
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Renny, so you're running about 170 Amps or so. Your motor and esc need some cooling, so how is that accomplished? And then you must have a way to automatically override throttle if lipos approach 70 to 80% drained?
>
> >
>
> >
>
> >
>
> > Motor cooling is handled via a small electric fan forward of the rudder pedals, an air vent in the nose cone that allows outside air to help cool the motor (and the cockpit), and 3 electric fans on the shelf behind the pilot's seat to cool the controller. When the batteries get low, warnings go off on the FCU, and I would then throttle back and turn off the FES. There is no automatic shutdown of the FES which allows the pilot to keep the FES running if there is an emergency situation. Thx - Renny
>
>
>
> On our latest instalations, we manage to arrange cooling also without electric fan infront of pedals. Motor itself has bigger centrifugal ventilator at back side!
>
>
>
> Regards, Luka

Luka,

It sounds like a number of incremental changes have been made to the FES system that have not yet been posted to your web site. Could you write a post detailing these changes and perhaps also let us know what's coming in the near future? Thanks,

SLB

[Greg Arnold]

On 9/29/2012 8:42 AM, slbair wrote:

>>
>>> Motor cooling is handled via a small electric fan forward of the rudder pedals, an air vent in the nose cone that allows outside air to help cool the motor (and the cockpit), and 3 electric fans on the shelf behind the pilot's seat to cool the controller. When the batteries get low, warnings go off on the FCU, and I would then throttle back and turn off the FES. There is no automatic shutdown of the FES which allows the pilot to keep the FES running if there is an emergency situation. Thx - Renny
>>
>>
>>
>> On our latest instalations, we manage to arrange cooling also without electric fan infront of pedals. Motor itself has bigger centrifugal ventilator at back side!
>>
>>
>>
>> Regards, Luka
>
> Luka,
>
> It sounds like a number of incremental changes have been made to the FES system that have not yet been posted to your web site. Could you write a post detailing these changes and perhaps also let us know what's coming in the near future? Thanks,
>
> SLB
>

Luka:

Since the prop now automatically stops in same position each time, does
this mean that the cross section shape of the fuselage at the nose no
longer has to be circular, but instead could be oval like on many
gliders? This would require the spinner to be oval -- does an oval
spinner shape present problems?

I second the idea of better information in one place on the web page.
Right now, anyone wanting accurate information must be a sleuth who
reads multiple webpages, who reads a PDF brochure, and who peruses RAS
postings by Luka and others. Sherlock Holmes, we need you!

[Dan Marotta]

I am putting together a list of all LAK owners in the USA and, when
finished, will email all owners with information of the FES installation,
expected cost, location, and expected installation time.

I have the list together (19 US owners!) but, unfortunately, the SSA website
will only allow me to get contact information for 5 members per day.
Therefore, it will take me another 3 or 4 days to get the message out to
prospective users. Hopefully, I can get the requisite 4 people to get the
group rate that Luka offered and I posted originally. I've already heard
from two prospects and, of course, myself.

Keep the discussion going!


"Renny" > wrote in message
...
On Friday, September 28, 2012 6:00:43 PM UTC-6, (unknown) wrote:
> On Monday, September 24, 2012 4:23:59 PM UTC-7, Renny wrote:
>
> > On Monday, September 24, 2012 4:53:12 PM UTC-6, Greg Arnold wrote: > On
> > 9/24/2012 3:39 PM, Renny wrote: > > > > > > > > Here's the URL for a PDF
> > brochure that was handed out at the 2012 Reno Convention on the FES.
> > Hopefully,
>
>
>
> Renny, so you're running about 170 Amps or so. Your motor and esc need
> some cooling, so how is that accomplished? And then you must have a way
> to automatically override throttle if lipos approach 70 to 80% drained?

Motor cooling is handled via a small electric fan forward of the rudder
pedals, an air vent in the nose cone that allows outside air to help cool
the motor (and the cockpit), and 3 electric fans on the shelf behind the
pilot's seat to cool the controller. When the batteries get low, warnings go
off on the FCU, and I would then throttle back and turn off the FES. There
is no automatic shutdown of the FES which allows the pilot to keep the FES
running if there is an emergency situation. Thx - Renny

[[email protected]]

Dne sobota, 29. september 2012 18:16:36 UTC+2 je oseba Greg Arnold napisala:
> On 9/29/2012 8:42 AM, slbair wrote:
>
>
>
> >>
>
> >>> Motor cooling is handled via a small electric fan forward of the rudder pedals, an air vent in the nose cone that allows outside air to help cool the motor (and the cockpit), and 3 electric fans on the shelf behind the pilot's seat to cool the controller. When the batteries get low, warnings go off on the FCU, and I would then throttle back and turn off the FES. There is no automatic shutdown of the FES which allows the pilot to keep the FES running if there is an emergency situation. Thx - Renny
>
> >>
>
> >>
>
> >>
>
> >> On our latest instalations, we manage to arrange cooling also without electric fan infront of pedals. Motor itself has bigger centrifugal ventilator at back side!
>
> >>
>
> >>
>
> >>
>
> >> Regards, Luka
>
> >
>
> > Luka,
>
> >
>
> > It sounds like a number of incremental changes have been made to the FES system that have not yet been posted to your web site. Could you write a post detailing these changes and perhaps also let us know what's coming in the near future? Thanks,
>
> >
>
> > SLB
>
> >
>
>
>
> Luka:
>
>
>
> Since the prop now automatically stops in same position each time, does
>
> this mean that the cross section shape of the fuselage at the nose no
>
> longer has to be circular, but instead could be oval like on many
>
> gliders? This would require the spinner to be oval -- does an oval
>
> spinner shape present problems?
>
>
>
> I second the idea of better information in one place on the web page.
>
> Right now, anyone wanting accurate information must be a sleuth who
>
> reads multiple webpages, who reads a PDF brochure, and who peruses RAS
>
> postings by Luka and others. Sherlock Holmes, we need you!


Dear Greg,

Your thinking is correct! For Silent we are using now already slightly oval - eliptic shape of spinner at fuselage front cut. Small amount of ovality does not present any problem, but need to explore possibilities of even higher ovality...
We will try to publish latest data and achievements on our website more regulary. Now pilots can sigh in for our newsletter, where those informations will be published when it will be apropriate.
Sign in for newsletter:
http://www.front-electric-sustainer.com/newsletter.php

Kind regards,

Luka Znidarsic, FES development

[Gary Hethcoat]

Anyone considering a jet (turbine) in their sailplane should read up on the R/C experience with these engines. I have not owned one personally, but I have read a lot about the experience. The big advantages are 1) power - they produce a huge amount of thrust 2) running reliability - once running, they rarely quit and 3) relatively low weight for the amount of thrust available. The disadvantages are 1) they are very inefficient and consume a huge amount of fuel very quickly 2) spool time - you have to think ahead of these engines since power will not be available the second you hit the throttle. This may be less of an issue in a glider vs. a R/C "rocket" with high wing loading :-)

Interesting that the critics of electric power always bring up the battery hazard issue. As if *gasoline* is not hazardous!!! Don't get Elon Musk started on that one :-) With a turbine you basically have a blowtorch installed in your aircraft! Not hazardous at all :-) There are *many* accounts of literal 'crash and burn' accidents with turbine powered R/C jets. In a crash, the high temperatures in the turbine mixed with spilled gasoline have predictable (firey) results! R/C jet owners have a fire extinguisher ready at all times.

The advantages of electric power have been well stated in this thread. The main disadvantages are weight, (relatively) low energy density and cost.

Personally, I think the future is electric. We've seen electric power almost completely displace gas on R/C fields. The advantages are just too compelling. The disadvantages lessen every year as newer, better technology comes online. There will always be a place for IC engines, but they are now becoming a niche in R/C flying, as I expect they will eventually in many other modes of transport.

Also interesting that we've been using the FES-style power arrangement in R/C self-launching gliders for many years now. It's really great to see it come online in the full-size community.

Gary Hethcoat
Northern California Soaring Association
(and long-time R/C pilot :-)

[Jim White[_3_]]

Jet - for the noise it makes...whoooaa

[[email protected]]

If I could get someone to retrofit my 30 year old Pegase101A with the FES sustainer, I would do it tomorrow :)

Since that is not available I will play PowerBall tonight and order a new one over the weekend.

But seriously - will FES have a presence at the convention in Feb? - someday I will have a sailplane with FES.

WH1

[Dan Marotta]

Does your Pegase have a circular cross section at the nose? Contact FES
at http://www.front-electric-sustainer.com/
and ask them if your glider is a good candidate.


On 1/6/2016 10:46 AM, wrote:
> If I could get someone to retrofit my 30 year old Pegase101A with the FES sustainer, I would do it tomorrow :)
>
> Since that is not available I will play PowerBall tonight and order a new one over the weekend.
>
> But seriously - will FES have a presence at the convention in Feb? - someday I will have a sailplane with FES.
>
> WH1

--
Dan, 5J

[Tony[_5_]]

circular nose is no longer required...as the FES Discus and Ventus show. The FES Controller will align the nosecone with the rest of the fuselage after shutdown.

[Casey[_2_]]

Last convention in Reno, Leo had a Silent FES there and TN is closer to SC than to Reno.

The Silent FES was nice. I like the LED strobe on the vertical too.

[[email protected]]

Pegase are basically the same fuselage as a ASW20 - just French - and 20's are on their list.

I did ask, but there is no one in the US doing the retro fit :( - I was hoping to look at FES more at the convention. I would even consider buying a ASW20 or ASW27 in Europe and shipping it back - but I do not know the process.

If it were available as a retro fit I bet there would be a long line. For people like myself that want to do XC and want to do some contests, I believe FES is a game changer. (I know the romance about landing out.....) The increased drag/weight may keep me off a podium, but that is not my total interest as my skill level.

WH1

[Renny[_2_]]

On Wednesday, January 6, 2016 at 2:33:25 PM UTC-7, wrote:
> Pegase are basically the same fuselage as a ASW20 - just French - and 20's are on their list.
>
> I did ask, but there is no one in the US doing the retro fit :( - I was hoping to look at FES more at the convention. I would even consider buying a ASW20 or ASW27 in Europe and shipping it back - but I do not know the process.
>
> If it were available as a retro fit I bet there would be a long line. For people like myself that want to do XC and want to do some contests, I believe FES is a game changer. (I know the romance about landing out.....) The increased drag/weight may keep me off a podium, but that is not my total interest as my skill level.
>
> WH1

Unfortunately, it is highly unlikely that you will ever see FES units installed as a retrofit on various glider models. There are many reasons for this including: regulatory issues, legal issues, cost, design issues, market potential, installation complexity, etc, etc, etc. I am sure Luka could explain these various issues in more detail should he wish, but due to these reasons and others, the focus of LZ Design has been to offer the FES as an option on new gliders. Now, it all first began with the LAK-17A, that Luka Znidarsic used as the initial test bed and proof of concept glider. He then actually retrofitted a few LAK-17As that were shipped to his facility for the installations.

It was then offered as an option on the new LAK-17B and the Silent 2. As many of you know, in the past year, the FES is now offered by Schempp-Hirth on the Ventus 2cxa and the Discus 2c. It will also be offered on the new Ventus. HPH is also offering the FES on the Shark 304eS.

Finally, I hate to be a pessimist on this "retrofit" idea for other models, but I am doubtful that this will ever become a reality (except for perhaps some additional LAK-17As). Now, that being said, we all know things can change (just like the weather) and one should "never say never," but this is basically where we are today.... Thx - Renny

[SF]

How about a solid rocket JATO type unit for a sustainer. No drag, no recharging, pretty reliable, 3,000 ft climb should be doable. It also involves fire which should help with the marketing ad campaign graphics. Push the button and hang on.

[son_of_flubber]

On Wednesday, January 6, 2016 at 5:14:56 PM UTC-5, SF wrote:
> How about a solid rocket JATO type unit for a sustainer.

I initially toyed with the idea of a single-use 3000 foot climb save-my-ass FES cost effectively powered by a boatload of alkaline D-cells. But I soon realized how much a FES would extend my range in routine use. That mountain ridge to the west that we rarely fly over because the cloudbase is rarely more than 500 feet higher? It takes hours to do an auto retrieve from the far side.

Why not go west, explore, use FES to get home if the cloudbase drops in the meantime. I want one.

[Jonathan St. Cloud]

This thread was originally about types of sustainer. Just a note, while the jet engines sound cool, they are effectively the same weight as a solo sustainer with the required fuel, they need a lot of fuel. and you cannot windmill them. For me a retractable small sustainer would be the best. Unfortunately the ASG-32 is the only such glider. Wish there was a single seat 18 meter with retractable electric sustainer.

[Casey[_2_]]

For the cost I would get a self launcher vice a sustainer. I know the Lak 17 FES can launch but I think they were originally and maybe still calling it a sustainer. For that kind of money I would want the glider manufacture to endorse launch. I think the Mini Lak and the Silent endorse launch. I would hate to have over 100k in a glider and self launch and something go wrong and insurance not pay off because I was launching a sustainer. Please correct me if I'm wrong.

I do like the ease of use of the FES and think its great

[[email protected]]

That's too bad Renny - I am sure you know allot more about it than I do :)

But it would be so good and even if it was fairly expensive - I bet the market would be there. There are so many really odd looking light aircraft flying that look like there were built in a garage using hammers and a few nails........ to bad you can't just take a ASW20 and call in home built and just promise not to crash in the middle of a town :) - a guy can dream :) LOL

I know that at our club and talking to pilots progressing thru Solo to XC - the primary hurdle is landing is a place that is not an airport. and it seems these days that rather than being a way to meet new farmer friends, Land outs are just trespassing.

I have not experience the Sustainer vs self launch as much of a hurdle. That (in my limited discussions) usually has more to do with convenience - most pilots are fine getting towed or shot of a winch. But getting between airports, where you are selecting fields as the only option............ that spooks many.

For simplicity, reliability and (lower hour) pilot acceptance - FES is the future (I think)

Saving for my Discus FES

WH1

[Dave Walsh]

At 01:24 07 January 2016, Casey wrote:
>For the cost I would get a self launcher vice a sustainer. I
know the Lak
>=
>17 FES can launch but I think they were originally and
maybe still calling
>=
>it a sustainer. For that kind of money I would want the
glider
>manufacture=
> to endorse launch. I think the Mini Lak and the Silent
endorse launch.
>I=
> would hate to have over 100k in a glider and self launch
and something go
>=
>wrong and insurance not pay off because I was launching a
sustainer.
>Pleas=
>e correct me if I'm wrong.
>
>I do like the ease of use of the FES and think its great
>
>
It's quite simple: it's either a self launch sailplane or not:
look at the specifications.
Additionally you are mixing Ultralights (the Silent) with
conventional sailplanes (the LAK17B FES). My understanding
is that is NOT legal, in Europe, to self launch the LAK17BFES
(or indeed any other true "sustainer" sailplane). It's been
done of course but it makes no sense with an electric power
plant, what little battery power you started with has now
gone so you have no useful sustainer performance left. Why
would you even think that's a good idea?

The Silent Electro is a different (lighter) animal, designed as
a self launch. You could launch to a modest height and have
some sensible retrieve capability but you're sitting in a
fragile (compared to a modern sailplane) structure: lower Va,
lower Vne etc. It's very nicely built and a joy to rig. It's not
much cheaper than a LAK17BFES......choices.

[Dan Marotta]

A few years back I asked FES about shipping a kit to the US to be
installed locally in my LAK-17a. The response I got was that, to
maintain quality, they would not provide kits. They would, however,
travel to the US at my expense and perform the installation for me. The
cost at the time was $28,000 and, if I could find 4 other gliders, they
would offer me a discount.

I haven't compared that price to the price difference on a new glider
with and without a FES but I would guess that it was in line with buying
a new glider. Travel, shipping, and lodging costs are considerable for
the duration of the installation.

On 1/6/2016 2:33 PM, wrote:
> Pegase are basically the same fuselage as a ASW20 - just French - and 20's are on their list.
>
> I did ask, but there is no one in the US doing the retro fit :( - I was hoping to look at FES more at the convention. I would even consider buying a ASW20 or ASW27 in Europe and shipping it back - but I do not know the process.
>
> If it were available as a retro fit I bet there would be a long line. For people like myself that want to do XC and want to do some contests, I believe FES is a game changer. (I know the romance about landing out.....) The increased drag/weight may keep me off a podium, but that is not my total interest as my skill level.
>
> WH1

--
Dan, 5J

[[email protected]]

Now that is interesting. bhanson..at..roitech.com - maybe we can chat off rec.soaring

All the FES gliders I have seen are 100k+ - you could get a nice ASW20 or even a ASW27 add 25k and still be within reach.

You would not end up with a glider that gets you to the Worlds or the top of a podium - but it would get you home :) and not in the middle of a field in the dark :) LOL

WH1

[Casey[_2_]]

On Thursday, January 7, 2016 at 8:45:05 AM UTC-5, Dave Walsh wrote:
> At 01:24 07 January 2016, Casey wrote:
> >For the cost I would get a self launcher vice a sustainer. I
> know the Lak
> >=
> >17 FES can launch but I think they were originally and
> maybe still calling
> >=
> >it a sustainer. For that kind of money I would want the
> glider
> >manufacture=
> > to endorse launch. I think the Mini Lak and the Silent
> endorse launch.
> >I=
> > would hate to have over 100k in a glider and self launch
> and something go
> >=
> >wrong and insurance not pay off because I was launching a
> sustainer.
> >Pleas=
> >e correct me if I'm wrong.
> >
> >I do like the ease of use of the FES and think its great
> >
> >
> It's quite simple: it's either a self launch sailplane or not:
> look at the specifications.
> Additionally you are mixing Ultralights (the Silent) with
> conventional sailplanes (the LAK17B FES). My understanding
> is that is NOT legal, in Europe, to self launch the LAK17BFES
> (or indeed any other true "sustainer" sailplane). It's been
> done of course but it makes no sense with an electric power
> plant, what little battery power you started with has now
> gone so you have no useful sustainer performance left. Why
> would you even think that's a good idea?
>
> The Silent Electro is a different (lighter) animal, designed as
> a self launch. You could launch to a modest height and have
> some sensible retrieve capability but you're sitting in a
> fragile (compared to a modern sailplane) structure: lower Va,
> lower Vne etc. It's very nicely built and a joy to rig. It's not
> much cheaper than a LAK17BFES......choices.

That's kinda my point.

But if I was a manufacture of anything. I would not come out with my best to begin with. I would come out with a sustainer and let the high rollers buy. Then come out with a more powerful self launcher. The high rollers will sell their sustainers for the self launchers. I bet auto manufactures do this as well as other companies.

I realize the specs of the Lak and Silent 2 Electro. Same system in 15m gliders. I would not call the Silent a ultralight with an empty wt of 452 lbs and VNe 137 mph. I would call it a 13.5m conventional. Just like I would not classify a 15m with an 18m or 20m. All are different. Now the Sparrow Hawk I would classify as Ultralight.

And for the sake of discussion I can substitute the GP 14 VELO for the Silent 2. Same VNe as and empty wt as Lak 17. http://www.gpgliders.com/gp-14-e-velo

13.5m class= Alisport Silent, GP 14 Velo, Mini Lak, Albastar AS 13.5,

And you are right...Its a sustainer or self launcher. Just like its a 13.5m or 15m or 18m or 20m, flapped or not.

I'm just saying I would not spend the money on a sustainer if I could get a self launcher. Someone that lives closer to a tow would choose differently.

[[email protected]]

Jets may be more thirsty than 2 stroke sustainers but the extra power and speed makes the additional fuel cost pale into insignificance - even more so when you think of it a a proportion of the capital and running costs of a new glider.

Electric will obviously evntually win out but battery technology is advancing only slowly compared to other technologies and the capital costs remain expensive. I don't know the cost of FES batteries but I reckon I could buy around 8000 litres of jet fuel for the cost of a set of Antares batteries - maybe more. I used about 100 litres last summer including a lot of testing rather than retrieve use.

( But I do rather fancy the GP14E Velo!)

[Dave Walsh]

Not sure I'd agree with your thinking on the marketing of the
sustainer and the self-launch glider (ignoring the Ultralights;
incidentally the Silent Electro is an ultralight in Europe).

As a long time owner of several self-launch sailplanes I'd say
self launch buyers and sustainer buyers tend to have different
priorities. Self launchers are heavier, costlier and more
complex: unless you do a lot of flying (say >200 hours per
year) their real running costs are more than a conventional
sailplane. Plus their glide performance, especially in weak
conditions, is worse: this is a real drawback. And when they
breakdown the costs can be truly fantastic: look up the cost of
rebuilding a Solo or rotary engine or, worse, buying a new
engine. Against this is the hard to quantify "independence" and
the ability to get home (usually). Remember all self-launch
owners are complete masters of that branch of accounting
known as "man maths".

Sustainer owners and buyers are a much saner bunch; lower
costs, lighter weight, minor (or nil) performance loss and you
still get home (usually). Not sure many go from sustainer to
self launch? I can see self launch owners going to FES though.
Dave Walsh

[[email protected]]

While I hear the advantage of other type of power - I think more people are comfortable throwing a switch, than firing up a jet or hoisting a boom. And I have never been around any engine that uses fuel and did not smell bad.

Plus you have to explain to your wife that you just purchased a jet, when she thought you were going to fly around the airport safe and sound :) lol

I still think pilots who are real racing pilots will go powerless and the vast majority of us would be more comfortable flipping a switch :) even if a Jet has that 007 appeal.

WH1

[Dave Walsh]

At 19:35 07 January 2016, wrote:
>Jets may be more thirsty than 2 stroke sustainers but the
extra power and
>s=
>peed makes the additional fuel cost pale into insignificance
- even more
>so=
> when you think of it a a proportion of the capital and
running costs of a
>=
>new glider.
>
>Electric will obviously evntually win out but battery
technology is
>advanci=
>ng only slowly compared to other technologies and the
capital costs remain
>=
>expensive. I don't know the cost of FES batteries but I
reckon I could
>bu=
>y around 8000 litres of jet fuel for the cost of a set of
Antares
>batteries=
> - maybe more. I used about 100 litres last summer
including a lot of
>test=
>ing rather than retrieve use.
>
>( But I do rather fancy the GP14E Velo!)

Well either you are buying really expensive Jet fuel or you
know a source of really cheap Antares batteries; I'd say you
might buy 20,000+ litres of Jet fuel.
>

[Bob Salvo[_2_]]

On Sunday, September 23, 2012 at 1:55:26 AM UTC-4, Luka Žnidarši� wrote:
> Dear gliderpilots!
>
> Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system:
>
> http://www.front-electric-sustainer.com/voting.php
>
> Thank you,
>
> Luka

How about an electric powered shrouded fan that produces 50 lbs of thrust!

https://www.youtube.com/watch?v=VBkkJdwF2Lo

[son_of_flubber]

On Thursday, January 7, 2016 at 8:45:05 AM UTC-5, Dave Walsh wrote:
> My understanding
> is that is NOT legal, in Europe, to self launch the LAK17BFES
> (or indeed any other true "sustainer" sailplane).

The MINI LAK 13.5 is being developed as a self-launch LSA (European spec LSA). I understand that it would get a Self-launch Experimental Glider Airworthiness Certificate in the USA. It has a lowish pilot weight limitation of 87 kg (192 lbs). It is less expensive than the Silent Electro II FES self-launch. Blanik America has a brochure and quotes a price.

[son_of_flubber]

On Thursday, January 7, 2016 at 10:45:11 PM UTC-5, son_of_flubber wrote:

> The MINI LAK 13.5 is being developed as a self-launch LSA (European spec LSA).

Correction: They're aiming for Ultralight in Europe (less than 300 kg all up weight).

[Surge]

On Thursday, 27 September 2012 00:06:31 UTC+2, wrote:
> For me electrical sustainer in a glider is the perfect solution. It links in to the spirit of the sport, beter than a turbine. But the propellor on the nose feels slightly off.... Especially when you consider the bugwipergarages becoming standard on the topsailplanes. We are spending more and more on reducing drag. Then this minor addition feels going against the flow. Why not a small pilon whit this nice foldable propellor you have engineered? Or am I the only one who has this uncomfortable feeling?

How about FES in an EDF (electric ducted fan) configuration instead of pylon mounted FES? The EDF could be mounted in the fuselage with doors than open and close for the inlet and exhaust.
Would this make any sense or be simpler than a pylon mounted system?
Would a smaller prop size make it less efficient and impractical?
The one advantage would be the removal of most of the pitching issue associated with pylon mounted systems.

If I had the money for a self launcher or sustainer equipped glider it would be FES due to simplicity, reliability and safety.
From a safety perspective I presume a battery fire would tend to be more isolated in a crash whereas with combustible fuel you and the glider could become engulfed in flames within seconds as fuel is splashed around.
As battery and fuel cell technology advances, alternative energy storage upgrades could be a possibility without having to purchase another glider.
I don't like the smell of gasoline or jet fuel nor the complexity with things that operate at high temperatures and need to be maintained regularly. A brushless electric motor can literally run for years with a decent set of bearings. That means less hassle and maybe lower maintenance costs over the long run depending on the battery technology being used.

A sustainer option would suite me perfectly. I don't need to operate autonomously and a winch launch to 1500 feet is cheap ($4.70 USD) and preserves power for when I may need it.

[Kevin Neave[_2_]]

Approximate prices as of spring 2015...

D2c 18m - 68k Euro
D2cT 18m - 85k Euro
D2c FES 18m - 93k Euro

All plus VAT.
All plus loads of "Options"

By the time you've added a trailer & sensible instrument fit you're looking
at around 150k Euro inc VAT, so difference between "traditional" turbo &
FES is less than the variation in exchange rates from week to week (Or day
to day at the moment!)

KN

At 16:44 07 January 2016, Dan Marotta wrote:
>
>I haven't compared that price to the price difference on a new glider
>with and without a FES but I would guess that it was in line with buying
>a new glider. Travel, shipping, and lodging costs are considerable for
>the duration of the installation.
>

[J. Nieuwenhuize]

When is a hybrid coming? FES plus a 10hp generator would be the ideal combination.

[Bruce Hoult]

On Friday, January 8, 2016 at 3:53:32 PM UTC+3, J. Nieuwenhuize wrote:
> When is a hybrid coming? FES plus a 10hp generator would be the ideal combination.

Solar cells.

It shouldn't be long before it's economic to embed solar cells under a thin smooth transparent layer (would gelcoat do?) of the entire upper surface of the wing.

At current efficiencies, a single seater with 10 sq m of wing will get about 2 hp, not 10, but that will still help as it'll be working almost all the time.

[Charlie M. (UH & 002 owner/pilot)]

On Friday, January 8, 2016 at 1:40:33 AM UTC-5, Surge wrote:
> On Thursday, 27 September 2012 00:06:31 UTC+2, wrote:
> > For me electrical sustainer in a glider is the perfect solution. It links in to the spirit of the sport, better than a turbine. But the propeller on the nose feels slightly off.... Especially when you consider the bugwiper garages becoming standard on the top sailplanes. We are spending more and more on reducing drag. Then this minor addition feels going against the flow. Why not a small pylon with this nice foldable propeller you have engineered? Or am I the only one who has this uncomfortable feeling?
>
> How about FES in an EDF (electric ducted fan) configuration instead of pylon mounted FES? The EDF could be mounted in the fuselage with doors than open and close for the inlet and exhaust.
> Would this make any sense or be simpler than a pylon mounted system?
> Would a smaller prop size make it less efficient and impractical?
> The one advantage would be the removal of most of the pitching issue associated with pylon mounted systems.
>
> If I had the money for a self launcher or sustainer equipped glider it would be FES due to simplicity, reliability and safety.
> From a safety perspective I presume a battery fire would tend to be more isolated in a crash whereas with combustible fuel you and the glider could become engulfed in flames within seconds as fuel is splashed around.
> As battery and fuel cell technology advances, alternative energy storage upgrades could be a possibility without having to purchase another glider.
> I don't like the smell of gasoline or jet fuel nor the complexity with things that operate at high temperatures and need to be maintained regularly. A brushless electric motor can literally run for years with a decent set of bearings. That means less hassle and maybe lower maintenance costs over the long run depending on the battery technology being used.
>
> A sustainer option would suite me perfectly. I don't need to operate autonomously and a winch launch to 1500 feet is cheap ($4.70 USD) and preserves power for when I may need it.

With retractable gear, mixers/controls, etc., not much room for a decent sized EDF. Unless of course, you want to make the fuselage larger, but that add's wetted area and reduces the performance.

[Dave Walsh]

At 14:52 08 January 2016, Charlie M. UH & 002 owner/pilot
wrote:
>On Friday, January 8, 2016 at 1:40:33 AM UTC-5, Surge
wrote:
>> On Thursday, 27 September 2012 00:06:31 UTC+2,

>wrot=
>e:
>> > For me electrical sustainer in a glider is the perfect
solution. It
>lin=
>ks in to the spirit of the sport, better than a turbine. But
the propeller
>=
>on the nose feels slightly off.... Especially when you
consider the
>bugwipe=
>r garages becoming standard on the top sailplanes. We are
spending more
>and=
> more on reducing drag. Then this minor addition feels
going against the
>fl=
>ow. Why not a small pylon with this nice foldable propeller
you have
>engine=
>ered? Or am I the only one who has this uncomfortable
feeling?
>>=20
>> How about FES in an EDF (electric ducted fan)
configuration instead of
>py=
>lon mounted FES? The EDF could be mounted in the
fuselage with doors than
>o=
>pen and close for the inlet and exhaust.
>> Would this make any sense or be simpler than a pylon
mounted system?
>> Would a smaller prop size make it less efficient and
impractical?
>> The one advantage would be the removal of most of the
pitching issue
>asso=
>ciated with pylon mounted systems.
>>=20
>> If I had the money for a self launcher or sustainer
equipped glider it
>wo=
>uld be FES due to simplicity, reliability and safety.
>> From a safety perspective I presume a battery fire would
tend to be more
>=
>isolated in a crash whereas with combustible fuel you and
the glider could
>=
>become engulfed in flames within seconds as fuel is
splashed around.
>> As battery and fuel cell technology advances, alternative
energy storage
>=
>upgrades could be a possibility without having to purchase
another glider.
>> I don't like the smell of gasoline or jet fuel nor the
complexity with
>th=
>ings that operate at high temperatures and need to be
maintained
>regularly.=
> A brushless electric motor can literally run for years with a
decent set
>o=
>f bearings. That means less hassle and maybe lower
maintenance costs over
>t=
>he long run depending on the battery technology being
used.
>>=20
>> A sustainer option would suite me perfectly. I don't need
to operate
>auto=
>nomously and a winch launch to 1500 feet is cheap ($4.70
USD) and
>preserves=
> power for when I may need it.
>
>With retractable gear, mixers/controls, etc., not much room
for a decent
>si=
>zed EDF. Unless of course, you want to make the fuselage
larger, but that
>a=
>dd's wetted area and reduces the performance.
>

I'd agree with most of the above: gasoline is certainly a
hazard in a crash but Lithium batteries are not exactly "safe"
in a crash, they too can burn and the combustion products
are very hazardous. Then there's the problem of several
hundred volts DC at large...
See:
http://www.bea.aero/fr/enquetes/2012/2012.semaine.36.pd
f

[Pierre Vav]

As a very proud of e very nice Lak17a, I asked Luka for the price of FES Retrofit.
Answer was quick, contact very nice.

Price was not.

I sold the Lak and bought an ASH25e.

[Justin Craig[_3_]]

Which sustainer system would you chose for your SAILPLANE?

Experience and skill.

If I wanted and aeroplane, I would have a ASH 31Mi or and Arcus M.

;)

[Peter Purdie[_3_]]

Fine if you want to never stretch the day, and enjoy landing in places
where unforeseen risks/hidden obstacles can cause expensive damage.

I have landed in more fields than I care to remember, and occasionally
beaten World Champions on competition tasks. I feel no shame in
knowing when the day is over and ending back at the field with an
intact ship ready for the next day.

Chacun a son gout.

At 15:37 11 January 2016, Justin Craig wrote:
>
>Which sustainer system would you chose for your SAILPLANE?
>
>Experience and skill.
>
>If I wanted and aeroplane, I would have a ASH 31Mi or and Arcus M.
>
>;)

[Andy Blackburn[_3_]]

On Thursday, January 7, 2016 at 10:40:33 PM UTC-8, Surge wrote:

> How about FES in an EDF (electric ducted fan) configuration instead of pylon mounted FES? The EDF could be mounted in the fuselage with doors than open and close for the inlet and exhaust.
> Would this make any sense or be simpler than a pylon mounted system?
> Would a smaller prop size make it less efficient and impractical?
> The one advantage would be the removal of most of the pitching issue associated with pylon mounted systems.
>

FES is by definition the front mounted ('F') variety not pylon mounted - just to nit-pick.

As to EDF, you might be able to get one big enough to climb a glider, but the efficiencies would, I suspect, be poor and electric sustainers already face a weight/range tradeoff that is marginal for many pilots. I expect the pylon-mounted sustainers with a larger prop would be the best compromise (reliable and fast deployment, minimal drag, acceptable range, low enough weight for an 18m glider to not face too much of a weight penalty. Whether it is appreciably more efficient than an FES prop would be interesting to know - my guess is they'd be a bit more efficient. FES wins for pure simplicity..

I'd rather carry batteries around than gasoline any day. Internal combustion engines (and turbines) are a recipe for lots of mechanical fiddling and maintenance in my experience.

9B

[[email protected]]

On Tuesday, January 12, 2016 at 3:16:41 PM UTC-5, Andy Blackburn wrote:
> On Thursday, January 7, 2016 at 10:40:33 PM UTC-8, Surge wrote:
>
> > How about FES in an EDF (electric ducted fan) configuration instead of pylon mounted FES? The EDF could be mounted in the fuselage with doors than open and close for the inlet and exhaust.
> > Would this make any sense or be simpler than a pylon mounted system?
> > Would a smaller prop size make it less efficient and impractical?
> > The one advantage would be the removal of most of the pitching issue associated with pylon mounted systems.
> >
>
> FES is by definition the front mounted ('F') variety not pylon mounted - just to nit-pick.
>
> As to EDF, you might be able to get one big enough to climb a glider, but the efficiencies would, I suspect, be poor and electric sustainers already face a weight/range tradeoff that is marginal for many pilots. I expect the pylon-mounted sustainers with a larger prop would be the best compromise (reliable and fast deployment, minimal drag, acceptable range, low enough weight for an 18m glider to not face too much of a weight penalty. Whether it is appreciably more efficient than an FES prop would be interesting to know - my guess is they'd be a bit more efficient. FES wins for pure simplicity.
>
> I'd rather carry batteries around than gasoline any day. Internal combustion engines (and turbines) are a recipe for lots of mechanical fiddling and maintenance in my experience.
>
> 9B

There are plenty of retractable engine gliders that, due to geometry changes to fit the engine etc, and/or poor doors, may well have as much drag rise over a pure glider as those 2 prop blades.
The down side to front motor is that, for almost all but the light gliders, there is not a good way to get enough ground clearance for a prop that will apply the power needed for self launch.
It is a very clever concept.
UH

[Ian[_2_]]

On 12/01/2016 22:16, Andy Blackburn wrote:

> I expect the pylon-mounted sustainers with a larger prop
> would be the best compromise (reliable and fast deployment, minimal
> drag, acceptable range, low enough weight for an 18m glider to not
> face too much of a weight penalty. Whether it is appreciably more
> efficient than an FES prop would be interesting to know - my guess is
> they'd be a bit more efficient. FES wins for pure simplicity.

If I were investing in a sustainer, my preference would also be for a
pylon mounted electric unit. Pylon retraction should be as reliable as
u/c retraction and time to extend/retract would not equate to
significant hight loss. Once the prop is in the breeze an electric drive
is equally reliable on a pylon as it is on a FES.

Pylon installation in existing fuselage designs should be easier than
FES and there would be fewer complications with cooling and instruments.
When a pylon motor is stowed, there is less drag than there is with a
folding prop and unlike FES there is very little chance of accidental
damage.

I am not sure what the drag/efficiency is of a FES verses a pylon +
large prop once they are both running. Maybe FES has an advantage,
giving it longer range?

> I'd rather carry batteries around than gasoline any day. Internal
> combustion engines (and turbines) are a recipe for lots of mechanical
> fiddling and maintenance in my experience.

I think the biggest requirement for a sustainer is reliable starting,
with minimum pilot work load and minimum hight loss. Electric has got to
win every time.

Now if FES technology and experience was to put into a pylon mounted
electric sustainer which could be retrofitted it into any 15m or 18m
fuselage originally designed to accommodate a sustainer, I might be
tempted to pawn my pension....

The tricky part is that the batteries may have to go into the wings.

Ian

[Casey[_2_]]

I wonder if nose cone in trailer has to be changed?

[Dave Walsh]

I think there is little doubt that the FES system has lower drag
(thus better performance) than a pylon mounted electric
motor. Pylons are weight and complication that the FES just
doesn't have. With the pylon stuck out and the engine not
running the drag will be much greater than a failed FES. Failed
pylon mounted engine/props also produce turbulence at the
elevator, masking feel, not a nice scenario.
Are there performance figures for pylon mounted electric
sustainers? Do such gliders exist?
I know it's not a correct comparison (as the props are so much
larger being self launchers) but with engine out and a
windmilling prop the 18m DG800B goes from 48:1 to 16:1; the
20m Antares20E goes from 55:1 to 30:1.
Anybody have figures for a failed FES? I'd guess the glide
angle would still be pretty good.
Dave Walsh

[Steve Leonard[_2_]]

On Wednesday, January 13, 2016 at 5:30:05 PM UTC-6, Dave Walsh wrote:
> I think there is little doubt that the FES system has lower drag
> (thus better performance) than a pylon mounted electric
> motor. Pylons are weight and complication that the FES just
> doesn't have. With the pylon stuck out and the engine not
> running the drag will be much greater than a failed FES. Failed
> pylon mounted engine/props also produce turbulence at the
> elevator, masking feel, not a nice scenario.
> Are there performance figures for pylon mounted electric
> sustainers? Do such gliders exist?
> I know it's not a correct comparison (as the props are so much
> larger being self launchers) but with engine out and a
> windmilling prop the 18m DG800B goes from 48:1 to 16:1; the
> 20m Antares20E goes from 55:1 to 30:1.
> Anybody have figures for a failed FES? I'd guess the glide
> angle would still be pretty good.
> Dave Walsh

If the FES fails, the blades fold back. Or, don't unfold in the first place. Only drag penalty would be on an SH if it didn't align so the nose cone isn't faired with the fuselage behind it. That is another part of the beauty of the FES.

Steve Leonard

[[email protected]]

On Wednesday, January 13, 2016 at 1:44:05 PM UTC-8, Casey wrote:
> I wonder if nose cone in trailer has to be changed?


Photos of the new nose cone:

https://www.facebook.com/lzdesign.si/posts/531887170295631

[bumper[_4_]]

On Wednesday, January 13, 2016 at 3:30:05 PM UTC-8, Dave Walsh wrote:
> I think there is little doubt that the FES system has lower drag
> (thus better performance) than a pylon mounted electric
> motor. Pylons are weight and complication that the FES just
> doesn't have. With the pylon stuck out and the engine not
> running the drag will be much greater than a failed FES.
> Dave Walsh

Dave,

I don't think so. A small prop is not as efficient as a large prop. In terms of thrust, it's better to move a lot of air slowly than a small amount of air faster. The Wright brothers got that part right, big props turning slowly are most efficient. In most glider applications, a pylon allows for a larger prop that does a nose mount. So if available energy limited, a pylon mounted larger prop offers significant advantages. Other examples are the human and solar powered aircraft

With the pylon prop stowed, there is essentially no drag penalty. The same cannot be said for FES, though I don't know what any drag penalty might be. On MKIV customer contacted me because his yaw string did not stream straight back in flight but stayed off to the side. We determined it was due to flow disruption from the stowed FES blade/s. Moving the yaw string further aft on the canopy apparently solved the problem. The point being that the stowed blade was not just tripping laminar flow behind the blade (I think stowed at roughly 3 and 9 o'clock) but was influencing a much larger area, as the string was obviously at 12 o'clock. Strange.

I agree a failed FES should have less drag than a failed and still extended pylon and prop. And the risk of being stuck with an extended but non functional FES should be near zero. Whatever degree of risk, for a stuck extended pylon, one might assign, my understanding is it's fairly rare in the ASH26E community (self launch, but the idea is the same). The engine's been running, so when it's time to get rid of the noise, the battery has adequate capacity to drive the linear actuator to lower the pylon - and the actuator has an easy time of it as it's not fighting air flow as it would be when extending the pylon in flight. I imagine there have been more instances of failure to extend pylons than getting them stowed.

[Tango Whisky]

Well, the main problem I see with FES is that it's plain ugly. Stemme has at least found a solution that keeps the blades out of sight.

Bert
Ventus cM TW

[[email protected]]

On Tuesday, January 12, 2016 at 1:52:08 PM UTC-8, wrote:
> On Tuesday, January 12, 2016 at 3:16:41 PM UTC-5, Andy Blackburn wrote:
> > On Thursday, January 7, 2016 at 10:40:33 PM UTC-8, Surge wrote:
> >
> > > How about FES in an EDF (electric ducted fan) configuration instead of pylon mounted FES? The EDF could be mounted in the fuselage with doors than open and close for the inlet and exhaust.
> > > Would this make any sense or be simpler than a pylon mounted system?
> > > Would a smaller prop size make it less efficient and impractical?
> > > The one advantage would be the removal of most of the pitching issue associated with pylon mounted systems.
> > >
> >
> > FES is by definition the front mounted ('F') variety not pylon mounted - just to nit-pick.
> >
> > As to EDF, you might be able to get one big enough to climb a glider, but the efficiencies would, I suspect, be poor and electric sustainers already face a weight/range tradeoff that is marginal for many pilots. I expect the pylon-mounted sustainers with a larger prop would be the best compromise (reliable and fast deployment, minimal drag, acceptable range, low enough weight for an 18m glider to not face too much of a weight penalty. Whether it is appreciably more efficient than an FES prop would be interesting to know - my guess is they'd be a bit more efficient. FES wins for pure simplicity.
> >
> > I'd rather carry batteries around than gasoline any day. Internal combustion engines (and turbines) are a recipe for lots of mechanical fiddling and maintenance in my experience.
> >
> > 9B
>
> There are plenty of retractable engine gliders that, due to geometry changes to fit the engine etc, and/or poor doors, may well have as much drag rise over a pure glider as those 2 prop blades.
> The down side to front motor is that, for almost all but the light gliders, there is not a good way to get enough ground clearance for a prop that will apply the power needed for self launch.
> It is a very clever concept.
> UH

To solve the prop size problem, would there be any way to "extend" the props once the glider is off the ground a few meters? And thus turning a FES into a "FEL" or "FEM" (no good acronyms here...)? Surely there is some mechanical way to do this? Has it been or is it being considered?

[J. Nieuwenhuize]

IMHO, this plus a small 4-stroke generator of 10-20 hp is the perfect system:
https://www.facebook.com/gpgliders/videos/995333550523888/

No noticeable drag if it fails to start, electric reliability and extreme range due to the generator.

[kirk.stant]

On Thursday, January 14, 2016 at 4:19:13 PM UTC-6, J. Nieuwenhuize wrote:
> IMHO, this plus a small 4-stroke generator of 10-20 hp is the perfect system:
> https://www.facebook.com/gpgliders/videos/995333550523888/
>
> No noticeable drag if it fails to start, electric reliability and extreme range due to the generator.

Looks nice, but could the drag caused by all those doors (even closed) not equal the drag of a closed FES prop?

Speaking of FES, why not have a single blade? Counterweight in the spinner (it's been around for a long time), fold the prop into a recess under the nose of the plane, cover with a door if you want to be really Gucci...

Kirk
66

[Jonathan St. Cloud]

Was wondering how the Arcus E's (electric motor from Lange) are selling compared to the gas engine model?

[krasw]

On Friday, 15 January 2016 01:16:21 UTC+2, Jonathan St. Cloud wrote:
> Was wondering how the Arcus E's (electric motor from Lange) are selling compared to the gas engine model?

Since Lange and Schempp are not in best terms (to put it mildly), Quintus and Arcus E are pretty much buried. Arcus E is a nice glider but propulsion system is not free of maintenance or problems.

[[email protected]]

On Thursday, January 14, 2016 at 11:06:50 PM UTC, kirk.stant wrote:
> On Thursday, January 14, 2016 at 4:19:13 PM UTC-6, J. Nieuwenhuize wrote:
> > IMHO, this plus a small 4-stroke generator of 10-20 hp is the perfect system:
> > https://www.facebook.com/gpgliders/videos/995333550523888/
> >
> > No noticeable drag if it fails to start, electric reliability and extreme range due to the generator.
>
> Looks nice, but could the drag caused by all those doors (even closed) not equal the drag of a closed FES prop?
>
> Speaking of FES, why not have a single blade? Counterweight in the spinner (it's been around for a long time), fold the prop into a recess under the nose of the plane, cover with a door if you want to be really Gucci...
>
> Kirk
> 66

There would have to be something far wrong with the fit of aft fuselage engine doors before they caused the same drag as a FES prop. The flight test of the Lak FES that has from time to time been cited as showing minimal drag actually shows around 4-8 kph difference for the same glide angle with the vents open (as would be normal during most gliding) - about one generation of design difference. Diagram on page 7:

http://www.front-electric-sustainer.com/Documents/IDAFLIEG%20test%20LAK17A%20FES_en.pdf

[JCK]

On Sunday, September 23, 2012 at 6:55:26 AM UTC+1, Luka Žnidarši� wrote:
> Dear gliderpilots!
>
> Manufacturers are not completely sure which is the way to go. So here you can vote for your favorite sustainer system:
>
> http://www.front-electric-sustainer.com/voting.php
>
> Thank you,
>
> Luka

It's interesting to see all your perspectives.
Personally, instant action without trim change wins every time....
Having witnessed a number of near misses, waiting for pylon extraction/engine firing - not to mention how the added pressure to pilot workload affects judgement. Sorry, for me it's a no-brainer.
The only real issue (for me), is the matter of span/vs weight sufficient that 13.5m span is enough?

Thanks

John

[2G]

The FES has an apparent advantage in higher reliability and, perhaps, lower cost, as well as less maintenance. An engine powered sustainer has a potentially longer self-retrieve distance. Jet powered sustainers have an uncertain reliability. These motors must be spun up to a very high RPM for starting. The motors themselves are not certified for aircraft use. I know of one pilot who landed out in a very bad area when his jet failed to start after 3 attempts (miraculously neither the glider or pilot suffered any damage).
I personally won't have a sustainer. I fly a lot in Utah and Nevada, and the sustainer probably won't get me over the mountain ranges I have to cross, or even get me to a landable field that may be 50+ miles away. But most pilots don't fly in this challenging environment.

Tom

[[email protected]]

About jet sustainers, it is not true to say that they are not cerified for aircraft use, the M+D (JS1) and PSR (Ventus) jets are EASA certified. As regards the need to be spun to high rpm to start - what is the issue there? Given that the turbines run at 75,000 to 100,000 rpm they have got to get up there somehow. The M+D jet is only spooled up to 8,000 rpm by the electric motor before the fuel system takes over (in two stages). 8000 rpm is nothing remarkable for an electric motor.

Lastly, we can't meaningfully judge the reliability of jets based on the experiences of pre-certification installations during the development stage - which includes all the JS1 installations prior to November 2015. My jet was installed under South African experimental type certificate. I think that the turbine and firmware are at or very close to the certification spec and so far I have had no failed starts out of 44 attempts.

In general I think that failures of all types of sustainer generally arise from ancillary components ( e.g. fuel pump, spark plugs, carburettor diaphragm etc) and electrical issues (e.g. relays, connections etc) and electric glider motors certainly have potential reliabilty vulnerabilities.

[Casey[_2_]]

> In general I think that failures of all types of sustainer generally arise from ancillary components ( e.g. fuel pump, spark plugs, carburettor diaphragm etc) and electrical issues (e.g. relays, connections etc) and electric glider motors certainly have potential reliabilty vulnerabilities.

I think the reliability of a FES would be more reliable than conventional motors due to less parts. However, over the long term a concern I would have about FES would be water/dirt/debrie in the motor and electrical components, assuming that not all are shielded and even then the deterioration over time. I would think that all gliders and motors that are 20-30 yrs old have had wiring, rubber tubing, and other non corrosive components replaced. A solid aluminum/metal engine can be rebuilt and wiring/tubbing replaced. But what about FES? I know the batteries are not an issue due to life expectancy and replacement. But what is the life expectancy of FES motor? How about the build up of dirt and debris from aero tow? Can the FES be air blown off or washed with water?

I really like and think the FES is great and the future but long term maintenance is key to resale ability and market.

[Surge]

On Thursday, 25 February 2016 13:38:56 UTC+2, Casey wrote:
> I think the reliability of a FES would be more reliable than conventional motors due to less parts. However, over the long term a concern I would have about FES would be water/dirt/debrie in the motor and electrical components, assuming that not all are shielded and even then the deterioration over time.

It all depends on the design and materials but people are happy to drive EV's (like one's from Tesla) through mud, water and other harsh environments for years on end without trouble.
Or gliders see a bit of dust for a few seconds once or twice per weekend so I'd hardly worry about it.
I've seen brushless motors run for years in extremely harsh environments without any maintenance and servicing. If the design is right, a brushless electric motor should outlast a combustion engine many times over even with zero maintenance.

[Surge]

On Thursday, 25 February 2016 13:38:56 UTC+2, Casey wrote:
> I think the reliability of a FES would be more reliable than conventional motors due to less parts. However, over the long term a concern I would have about FES would be water/dirt/debrie in the motor and electrical components, assuming that not all are shielded and even then the deterioration over time.

It all depends on the design and materials but people are happy to drive EV's (like one's from Tesla) through mud, water and other harsh environments for years on end without trouble.
Our gliders see a bit of dust for a few seconds once or twice per weekend so I'd hardly worry about it.
I've seen brushless motors run for years in extremely harsh environments without any maintenance and servicing. If the design is right, a brushless electric motor should outlast a combustion engine many times over even with zero maintenance.

[[email protected]]

On Thursday, February 25, 2016 at 1:11:48 PM UTC, Surge wrote:
If the design is right, a brushless electric motor should outlast a combustion engine many times over even with zero maintenance.

"should" - but I know of a case where that is not so, which is why I suggest caution before accepting very optimistic claims about electric glider reliability.

[Renny[_2_]]

On Thursday, February 25, 2016 at 6:53:37 AM UTC-7, wrote:
> On Thursday, February 25, 2016 at 1:11:48 PM UTC, Surge wrote:
> If the design is right, a brushless electric motor should outlast a combustion engine many times over even with zero maintenance.
>
> "should" - but I know of a case where that is not so, which is why I suggest caution before accepting very optimistic claims about electric glider reliability.

Well, let's see..Nothing really is 100% reliable in this world especially in the world of sustainers and self-launchers. At home if I flip a light switch I cannot be 100% sure that the light will come on...Now, it probably will and it is probably 99.99% reliable, but there is no real guarantee and things can go wrong....

I brought the first FES on a LAK-17b into the US over 4 years ago. I have started it many dozens of time (I always start it on the ground before flight as a pre-flight check). It has never failed me, but I also know that the next time it might not start. What I also know is that if does not start I am still a "pure" glider and there is no additional drag penalty to worry about, so I can just proceed and hope for a thermal or if not, simply make a normal landing.

We all know there are no guarantees, but when it comes to reliability and simplicity IMHO I continue to strongly favor the FES over any other sort of sustainer system. Now, tomorrow someone may develop a better mousetrap, but for me and for now, the FES is the "answer."

Finally, on the maintenance question, there essentially is no maintenance for the FES. I fly in New Mexico and have not seen any dirt or dust issues. I realize 4 years is not too long a period for an evaluation, but I will report back in the coming years if any maintenance issues surface.

Thanks - Renny

[[email protected]]

I agree - FES seems the future.

BUT - now after the SSA Convention..... the 13.5 self launchers are looking so inviting. I origionally thought Sustainer was the way to go on a 15m with 18m tips. But now the 13.5 are claiming 40+:1 glide ratio. next year will be decision time :) good problem to have!

FES seems to dominate the Convention floor.

WH1

[son_of_flubber]

FES rings all of my bells, but putting aside factors like wingspan, L/D, Vne, what is the additional cost and benefit of Front_Electric_Self_Launch (FESL) compared to FES?

How much does FESL add to the dollar cost of a similar F_Electric_Sustainer sailplane?

What drawbacks does FESL bring with it? The Mini-LAK has a pilot weight limitation for FESL. It has a tall main gear for prop clearance; how does that affect sight picture and stability for landing and takeoff? The tall gear can absorb a lot of landing shock, but would it be less robust and break?

If a towplane were available, I'd take a tow to 1500+ even if I had FESL, so how often would I ever use FESL? (Half the fun of soaring for me is the people on the ground, so I'm not attracted to launching by myself.) I'd take the tow to conserve battery charge for sustained flight, and I like the climb rate behind a Pawnee on a sinky tree lined short field. I know people with gas self-launchers that take aerotows for similar reasons.

FES is a very clean, simple and big payback feature. FESL not so much. I'm tempted to go with FESL because of extra feature of self launch and minimal cost differential between FES and FESL, but it seems a bit crazy to paying any price for a feature that I don't anticipate using, especially if there are additional non-dollar costs/tradeoffs.

[son_of_flubber]

On Thursday, February 25, 2016 at 1:15:33 AM UTC-5, 2G wrote:

> I personally won't have a sustainer. I fly a lot in Utah and Nevada, and the sustainer probably won't get me over the mountain ranges I have to cross, or even get me to a landable field that may be 50+ miles away.

But what about the use case where you plan to get home as a pure glider and use the FES to get you the last five miles to home or five miles to a decent landout field when you're a bit too optimistic? What about using FES for a few minutes when you have a PT3 or hit strong sink on final? What about using FES for a few minutes to find the next thermal before you descend below the 'lift band'?

From far off Vermont, there seem to be a lot of uses for FES in the SW that do not involve climbing above mountain ranges or sustaining flight at constant altitude for 50 miles.

On the other hand, I'm under the impression comparing SW and back east soaring, the SW has higher AGL cloudbase and stronger lift, so landouts are easier to avoid, so FES is less of a value proposition. Back east with lower AGL cloudbases and weaker lift, FES has more appeal, especially in areas with poorer landout options.


Questions about FES and Density Altitude:

I understand that High Density Altitude would reduce FES climb rate and that would reduce the value of FES out west (and electric self-launch would be impractical).

But how does Density Altitude affect FES range assuming level sustained flight? Sure, the prop would get less bite on thinner air and therefore the prop rpm would need to be higher to produce the same thrust, but battery charge rundown is proportional to thrust produced over time. I'm thinking that if the motor has the rpm for climbing at low density altitude, it would have the rpm for sustaining at high density altitude. Is the efficiency of FES lower at higher RPM?

[[email protected]]

I am no expert - but from the info at the convention:

Today there is no FESSL over 13.5m - it is a weight issue. the FES sustainer comes in 15m & 18m . There is one new Polish 13.5 with Electric motor on a boom, also self launching.

the 13.5m seem to have gained glide ratio - going from 37:1 to mid 40's:1 (if you believe the brochure.

I am also inclined to believe most people will opt to aero-tow with more reserve to get home - but having an option to fly on a weekday when no one is around to tow???? inviting, no.

WH1

[son_of_flubber]

On Thursday, February 25, 2016 at 4:09:07 PM UTC-5, wrote:

> the 13.5m seem to have gained glide ratio - going from 37:1 to mid 40's:1

As a recreational pilot with small interest in contests, glide ratio seems much less important with FES. If I'm planning to land with the batteries half discharged, the FES will greatly extend my range for the day (and give me the same range as a higher L/D ship). If I'm flying XC with friends with better L/D ships, I can run the FES between thermals, compensate for my inferior polar, and keep up with the higher L/D ships.

If I ever compete it will be in handicapped club class, so 37:1 seems adequate.

[2G]

On Thursday, February 25, 2016 at 2:26:37 AM UTC-8, wrote:
> About jet sustainers, it is not true to say that they are not cerified for aircraft use, the M+D (JS1) and PSR (Ventus) jets are EASA certified. As regards the need to be spun to high rpm to start - what is the issue there? Given that the turbines run at 75,000 to 100,000 rpm they have got to get up there somehow. The M+D jet is only spooled up to 8,000 rpm by the electric motor before the fuel system takes over (in two stages). 8000 rpm is nothing remarkable for an electric motor.
>
> Lastly, we can't meaningfully judge the reliability of jets based on the experiences of pre-certification installations during the development stage - which includes all the JS1 installations prior to November 2015. My jet was installed under South African experimental type certificate. I think that the turbine and firmware are at or very close to the certification spec and so far I have had no failed starts out of 44 attempts.
>
> In general I think that failures of all types of sustainer generally arise from ancillary components ( e.g. fuel pump, spark plugs, carburettor diaphragm etc) and electrical issues (e.g. relays, connections etc) and electric glider motors certainly have potential reliabilty vulnerabilities.

Ok, so what you are saying is that jets installed in the last 3 months are reliable. My experience has been that engine installation problems may take years - not months - to reveal themselves. This might be ok if you exercise due caution, primarily having a landable field within easy reach. Jets do have the advantage that they are low vibration, an issue with a reciprocating piston engine (I really like my Wankel for this reason). On the down side, they consume a lot of fuel.

Tom

[[email protected]]

I am *not* saying that jets installed in the last 3 months are reliable.

I am saying that to judge the reliability of the jets in gliders it is only meaningful consider aircraft with the fully developed specification - just as we would do for any other product.

[2G]

On Friday, February 26, 2016 at 1:01:25 AM UTC-8, wrote:
> I am *not* saying that jets installed in the last 3 months are reliable.
>
> I am saying that to judge the reliability of the jets in gliders it is only meaningful consider aircraft with the fully developed specification - just as we would do for any other product.

You did say that "we can't meaningfully judge the reliability of jets based on the experiences of pre-certification installations during the development stage - which includes all the JS1 installations prior to November 2015".. This isn't an endorsement of jet engines installations that are certified, so I stand corrected. I would like to know the differences between uncertified jet and certified jet installations; did they uncover problems and fix them, or is the failure mode still there? You are right: there are a lot of components in any engine installation and it only requires the failure of one of them to prevent a start. The more we share information the better we will understand the strengths and weaknesses of each propulsion system. And don't count on the manufacturers to do this!

Tom

[[email protected]]

Tom, I am not privvy to the details of the development of the JS1 jet but I have heard about some things along the way:

Change to the tolerances of the tiny gap between the rotor and the casing - corrected surging on starting at at typical South African altitudes.

ECU firmware changes.

Increased fuel pressure and smaller injector nozzles - for better fuel misting and starting.

Electronic component change in the ECU - to correct wrong voltage delivery to the glow plug leading to glow plug failures.

The uncertainties that I have relate to the electronics rather than the turbine - that and making sure the fuel is clean.