Advice on motor glider wanted - FES - Jet - Engine

[J W]

Seeking advice for a cheapish motor glider but a good investment is
more important.

Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
and HPH Shark.

Concerned that there are very few registered and certified in the UK so
may not be a good investment?

Like the idea of short span, low weight, carbon fibre construction as I’m

not so young and will be flying from rough grass strips. Fly for fun and
not in to competitions.

Would consider electric sustainer but think an engine or jet will be
preferable for range, allowing time to explore mountains and wave.

Suggestions welcomed, Thanks.

[Bob Caldwell (BC)]

On Friday, December 9, 2016 at 7:00:05 AM UTC-7, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.

I have a 2005 Ventus 2cxT 15/18 meter for sale with sustainer a engine. Very well equipped and in excellent condition. Reply if interested to rcaldwell at ponderosa-assoc dot com and I can send details and photos.

[JS]

On Friday, December 9, 2016 at 6:00:05 AM UTC-8, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.

Pik20E? Probably the best value for a self-launcher.
Or available soon, a certified M+D jet sustainer installation for the LS4.
Jim

[[email protected]]

On Friday, December 9, 2016 at 7:00:05 AM UTC-7, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.

I think a Silent 2 Electro, 13.5m electric self-launcher would meet your needs well. Or, just buy Bob's Ventus 2cxT, I can vouch that it is in meticulous condition!

Charlie

[Renny[_2_]]

On Friday, December 9, 2016 at 7:00:05 AM UTC-7, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.

Another option you may want to consider is the miniLAK FES! It's a 13.5 meter, electric self-launcher and it uses the well-proven FES.

Here's a very nice video on the miniLAK FES:

https://www.youtube.com/watch?v=5wEwg7X-fj4

Good luck! - Renny

[J W[_2_]]

At 23:02 09 December 2016, Renny wrote:
>On Friday, December 9, 2016 at 7:00:05 AM UTC-7, J W wrote:
>> Seeking advice for a cheapish motor glider but a good investment
is=20
>> more important.
>>=20
>> Was considering the newer types like the 13.5 metre Mini LAK, Silent
2=20
>> and HPH Shark.
>>=20
>> Concerned that there are very few registered and certified in the UK
so=
>=20
>> may not be a good investment?
>>=20
>> Like the idea of short span, low weight, carbon fibre construction as
I=
>=E2=80=99m
>>=20
>> not so young and will be flying from rough grass strips. Fly for fun
and=
>=20
>> not in to competitions.
>>=20
>> Would consider electric sustainer but think an engine or jet will
be=20
>> preferable for range, allowing time to explore mountains and wave.
>>=20
>> Suggestions welcomed, Thanks.
>
>Another option you may want to consider is the miniLAK FES! It's a
13.5
>met=
>er, electric self-launcher and it uses the well-proven FES.
>
>Here's a very nice video on the miniLAK FES:
>
>https://www.youtube.com/watch?v=3D5wEwg7X-fj4
>
>Good luck! - Renny
>
Thanks Renny, would like to see it but the link won't work. Will try a
search

[J W[_2_]]

At 22:37 09 December 2016, wrote:
>On Friday, December 9, 2016 at 7:00:05 AM UTC-7, J W wrote:
>> Seeking advice for a cheapish motor glider but a good investment
is=20
>> more important.
>>=20
>> Was considering the newer types like the 13.5 metre Mini LAK, Silent
2=20
>> and HPH Shark.
>>=20
>> Concerned that there are very few registered and certified in the UK
so=
>=20
>> may not be a good investment?
>>=20
>> Like the idea of short span, low weight, carbon fibre construction as
I=
>=E2=80=99m
>>=20
>> not so young and will be flying from rough grass strips. Fly for fun
and=
>=20
>> not in to competitions.
>>=20
>> Would consider electric sustainer but think an engine or jet will
be=20
>> preferable for range, allowing time to explore mountains and wave.
>>=20
>> Suggestions welcomed, Thanks.
>
>I think a Silent 2 Electro, 13.5m electric self-launcher would meet your
>ne=
>eds well. Or, just buy Bob's Ventus 2cxT, I can vouch that it is in
>meticul=
>ous condition!
>
>Charlie
>
Thanks for the positive comment Charlie. Would have a look at Bob's but
don't think he is in the UK?

[Renny[_2_]]

On Friday, December 9, 2016 at 5:00:05 PM UTC-7, J W wrote:
> At 23:02 09 December 2016, Renny wrote:
> >On Friday, December 9, 2016 at 7:00:05 AM UTC-7, J W wrote:
> >> Seeking advice for a cheapish motor glider but a good investment
> is=20
> >> more important.
> >>=20
> >> Was considering the newer types like the 13.5 metre Mini LAK, Silent
> 2=20
> >> and HPH Shark.
> >>=20
> >> Concerned that there are very few registered and certified in the UK
> so=
> >=20
> >> may not be a good investment?
> >>=20
> >> Like the idea of short span, low weight, carbon fibre construction as
> I=
> >=E2=80=99m
> >>=20
> >> not so young and will be flying from rough grass strips. Fly for fun
> and=
> >=20
> >> not in to competitions.
> >>=20
> >> Would consider electric sustainer but think an engine or jet will
> be=20
> >> preferable for range, allowing time to explore mountains and wave.
> >>=20
> >> Suggestions welcomed, Thanks.
> >
> >Another option you may want to consider is the miniLAK FES! It's a
> 13.5
> >met=
> >er, electric self-launcher and it uses the well-proven FES.
> >
> >Here's a very nice video on the miniLAK FES:
> >
> >https://www.youtube.com/watch?v=3D5wEwg7X-fj4
> >
> >Good luck! - Renny
> >
> Thanks Renny, would like to see it but the link won't work. Will try a
> search

Hmmm...OK..Try the LAK website here and you will see it..

http://www.lak.lt/

Thx - Renny

[J W[_2_]]

At 22:37 09 December 2016, wrote:
>On Friday, December 9, 2016 at 7:00:05 AM UTC-7, J W wrote:
>> Seeking advice for a cheapish motor glider but a good investment
is=20
>> more important.
>>=20
>> Was considering the newer types like the 13.5 metre Mini LAK, Silent
2=20
>> and HPH Shark.
>>=20
>> Concerned that there are very few registered and certified in the UK
so=
>=20
>> may not be a good investment?
>>=20
>> Like the idea of short span, low weight, carbon fibre construction as
I=
>=E2=80=99m
>>=20
>> not so young and will be flying from rough grass strips. Fly for fun
and=
>=20
>> not in to competitions.
>>=20
>> Would consider electric sustainer but think an engine or jet will
be=20
>> preferable for range, allowing time to explore mountains and wave.
>>=20
>> Suggestions welcomed, Thanks.
>
>I think a Silent 2 Electro, 13.5m electric self-launcher would meet your
>ne=
>eds well. Or, just buy Bob's Ventus 2cxT, I can vouch that it is in
>meticul=
>ous condition!
>
>Charlie
>
Thanks for the positive comment Charlie. Would have a look at Bob's but
don't think he is in the UK?

[Hoops]

On Friday, December 9, 2016 at 2:00:05 PM UTC, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.



On Friday, December 9, 2016 at 2:00:05 PM UTC, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.



On Friday, December 9, 2016 at 2:00:05 PM UTC, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.

[[email protected]]

Before you buy a jet powered glider, consider the noise level. Our neighbors would shut down our Gliderport if we allowed them to use their engines in the area.

Tom

[J W[_2_]]

At 19:35 10 December 2016, wrote:
>Before you buy a jet powered glider, consider the noise level. Our
>neighbors would shut down our Gliderport if we allowed them to use their
>engines in the area.
>
>Tom
>

Never thought of that, thought with them being so small they would not be
noisy. Was intending to use it away from the airfield but good point.

[Doug B]

On Friday, December 9, 2016 at 9:00:05 AM UTC-5, J W wrote:
> Seeking advice for a cheapish motor glider but a good investment is
> more important.
>
> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
> and HPH Shark.
>
> Concerned that there are very few registered and certified in the UK so
> may not be a good investment?
>
> Like the idea of short span, low weight, carbon fibre construction as I’m
>
> not so young and will be flying from rough grass strips. Fly for fun and
> not in to competitions.
>
> Would consider electric sustainer but think an engine or jet will be
> preferable for range, allowing time to explore mountains and wave.
>
> Suggestions welcomed, Thanks.

I'm new to these jet engine sustainers but I'm interested as well. I have a few major concerns: From what I can gather, they have limited run times, like 10 minutes. Also nobody seems to be saying what the TBO is on these little jets. It might be as low as 50 hours but I'm not sure. And, what is the overhaul cost and therefore, what is the hourly cost of operation?

[Jonathan St. Cloud]

I believe the overhaul time is 25 hours, at least for the HpH gliders.

On Tuesday, January 3, 2017 at 9:21:45 AM UTC-8, Doug B wrote:

> I'm new to these jet engine sustainers but I'm interested as well. I have a few major concerns: From what I can gather, they have limited run times, like 10 minutes. Also nobody seems to be saying what the TBO is on these little jets. It might be as low as 50 hours but I'm not sure. And, what is the overhaul cost and therefore, what is the hourly cost of operation?

[Paul Ruskin[_2_]]

The HpH ones run as long as you have fuel left - maybe 30-40 mins at a reasonable power setting. Time to overhaul is 50 hours, which at the rate I use mine is going to be somewhere between 10 and 20 years. Cost is said to be a few hundred euros - it's basically looking at the bearings.

Paul


On Tuesday, January 3, 2017 at 6:01:16 PM UTC, Jonathan St. Cloud wrote:
> I believe the overhaul time is 25 hours, at least for the HpH gliders.

[Dan Marotta]

Jets are cool, no doubt, and highly reliable, but they're very noisy
and, at the speeds gliders fly, very inefficient. I don't know how they
cost compared with a Wankel or piston engine, but I wouldn't have one.
The novelty will wear off.

My $0.02...

On 1/3/2017 10:21 AM, Doug B wrote:
> On Friday, December 9, 2016 at 9:00:05 AM UTC-5, J W wrote:
>> Seeking advice for a cheapish motor glider but a good investment is
>> more important.
>>
>> Was considering the newer types like the 13.5 metre Mini LAK, Silent 2
>> and HPH Shark.
>>
>> Concerned that there are very few registered and certified in the UK so
>> may not be a good investment?
>>
>> Like the idea of short span, low weight, carbon fibre construction as I’m
>>
>> not so young and will be flying from rough grass strips. Fly for fun and
>> not in to competitions.
>>
>> Would consider electric sustainer but think an engine or jet will be
>> preferable for range, allowing time to explore mountains and wave.
>>
>> Suggestions welcomed, Thanks.
> I'm new to these jet engine sustainers but I'm interested as well. I have a few major concerns: From what I can gather, they have limited run times, like 10 minutes. Also nobody seems to be saying what the TBO is on these little jets. It might be as low as 50 hours but I'm not sure. And, what is the overhaul cost and therefore, what is the hourly cost of operation?

--
Dan, 5J

[krasw]

The inefficiency comes from simple single stage turbine without bypass and low operating temperatures (compared to real turbofans).

[Paul Ruskin[_2_]]

On Wednesday, January 4, 2017 at 3:48:53 PM UTC, Dan Marotta wrote:
> Jets are cool, no doubt, and highly reliable, but they're very noisy
> and, at the speeds gliders fly, very inefficient. I don't know how they
> cost compared with a Wankel or piston engine, but I wouldn't have one.
> The novelty will wear off.
>

Noise can certainly be an issue, and you wouldn't want to use them much near your home site. But for us glider pilots, efficiency is not a big issue (we don't use it enough to worry). However, they have a very distinct advantage over a piston or wankel, and that's the lack of drag when you extend them.

That means that your commit height is much lower - people I know with conventional engines have to start them above 1000 ft AGL (some use considerably higher) and be downwind on a suitable landing area in case they don't start. With a jet, there's effectively no extra drag, so waiting until 500 ft AGL is perfectly feasible - or you can be further away from the field. That's the difference between completing a flight and not doing so, surprisingly often.

For me, at the moment it's a toss up between jet and FES - though I suspect within a few years FES will win out as battery technology gets better.

Paul

[Dan Marotta]

One problem I've seen is getting low away from a landable area following
flight in very cold air, e.g., wave. Whereas my Stemme has very little
increase in drag during engine start, and it starts quickly and
reliably, there's a requirement not to use much power until the oil
temperature reaches a certain level. Even with cowl flaps closed, that
can take 5 minutes or more to achieve. Fortunately, with power just
above idle, the Stemme has little to no decent.

Having flown turbojets in Alaska and turbofans in the lower 48, I don't
recall any cautions about oil temperature, though good sense should
prevail. There should be enough temperature for oil to circulate. The
jets would start and run just fine at -40 deg F.

On 1/7/2017 11:31 AM, Paul Ruskin wrote:
> On Wednesday, January 4, 2017 at 3:48:53 PM UTC, Dan Marotta wrote:
>> Jets are cool, no doubt, and highly reliable, but they're very noisy
>> and, at the speeds gliders fly, very inefficient. I don't know how they
>> cost compared with a Wankel or piston engine, but I wouldn't have one.
>> The novelty will wear off.
>>
> Noise can certainly be an issue, and you wouldn't want to use them much near your home site. But for us glider pilots, efficiency is not a big issue (we don't use it enough to worry). However, they have a very distinct advantage over a piston or wankel, and that's the lack of drag when you extend them.
>
> That means that your commit height is much lower - people I know with conventional engines have to start them above 1000 ft AGL (some use considerably higher) and be downwind on a suitable landing area in case they don't start. With a jet, there's effectively no extra drag, so waiting until 500 ft AGL is perfectly feasible - or you can be further away from the field. That's the difference between completing a flight and not doing so, surprisingly often.
>
> For me, at the moment it's a toss up between jet and FES - though I suspect within a few years FES will win out as battery technology gets better.
>
> Paul
>

--
Dan, 5J

[Bruce Hoult]

On Saturday, January 7, 2017 at 9:31:46 PM UTC+3, Paul Ruskin wrote:
> On Wednesday, January 4, 2017 at 3:48:53 PM UTC, Dan Marotta wrote:
> > Jets are cool, no doubt, and highly reliable, but they're very noisy
> > and, at the speeds gliders fly, very inefficient. I don't know how they
> > cost compared with a Wankel or piston engine, but I wouldn't have one.
> > The novelty will wear off.
> >
>
> Noise can certainly be an issue, and you wouldn't want to use them much near your home site. But for us glider pilots, efficiency is not a big issue (we don't use it enough to worry). However, they have a very distinct advantage over a piston or wankel, and that's the lack of drag when you extend them.
>
> That means that your commit height is much lower - people I know with conventional engines have to start them above 1000 ft AGL (some use considerably higher) and be downwind on a suitable landing area in case they don't start. With a jet, there's effectively no extra drag, so waiting until 500 ft AGL is perfectly feasible - or you can be further away from the field. That's the difference between completing a flight and not doing so, surprisingly often.
>
> For me, at the moment it's a toss up between jet and FES - though I suspect within a few years FES will win out as battery technology gets better.

Isn't FES already better?

According to reviews, 30 kg of batteries and 30 kg of jet fuel both seem to provide about 90 miles or 1 hour of range. FES provides more thrust/climb rate, is instant starting, non-smelly/mess, much quieter, the motor is lighter. Liquid fuels take minutes to refuel rather than hours, but that's probably not a limiting factor for a recreational glider. LIPO batteries may be a bit more likely to immolate themselves than liquid fuels but the risk is pretty low with both and you do have insurance and a parachute I hope :-)

[AS]

On Saturday, January 7, 2017 at 3:10:38 PM UTC-5, Dan Marotta wrote:
> One problem I've seen is getting low away from a landable area following
> flight in very cold air, e.g., wave. Whereas my Stemme has very little
> increase in drag during engine start, and it starts quickly and
> reliably, there's a requirement not to use much power until the oil
> temperature reaches a certain level. Even with cowl flaps closed, that
> can take 5 minutes or more to achieve. Fortunately, with power just
> above idle, the Stemme has little to no decent.
>
> Having flown turbojets in Alaska and turbofans in the lower 48, I don't
> recall any cautions about oil temperature, though good sense should
> prevail. There should be enough temperature for oil to circulate. The
> jets would start and run just fine at -40 deg F.
>
Dan, as far as I know, the small jets we are talking about here or at east the one I looked at seriously in an ASW-20CLJ do not have any oil circuit. The main bearings are lubricated by the jet fuel which is fortified by turbine oil.

Uli

>

[Dan Marotta]

Oh! Learn something new every day. That's a good thing!

On 1/7/2017 4:13 PM, AS wrote:
> On Saturday, January 7, 2017 at 3:10:38 PM UTC-5, Dan Marotta wrote:
>> One problem I've seen is getting low away from a landable area following
>> flight in very cold air, e.g., wave. Whereas my Stemme has very little
>> increase in drag during engine start, and it starts quickly and
>> reliably, there's a requirement not to use much power until the oil
>> temperature reaches a certain level. Even with cowl flaps closed, that
>> can take 5 minutes or more to achieve. Fortunately, with power just
>> above idle, the Stemme has little to no decent.
>>
>> Having flown turbojets in Alaska and turbofans in the lower 48, I don't
>> recall any cautions about oil temperature, though good sense should
>> prevail. There should be enough temperature for oil to circulate. The
>> jets would start and run just fine at -40 deg F.
>>
> Dan, as far as I know, the small jets we are talking about here or at east the one I looked at seriously in an ASW-20CLJ do not have any oil circuit. The main bearings are lubricated by the jet fuel which is fortified by turbine oil.
>
> Uli
>

--
Dan, 5J

[Steve Koerner]

I side with Bruce. It's pretty obvious to me that FES is the better choice.. I believe Bruce left off the most important advantage of FES...

That being the higher inherent reliability of operation. I can't prove it, but my own feeling is that FES would be an order of magnitude more reliable in starting up. And you'll know much more quickly whether it did or did not. The only real downside to FES is the drag that the folded props will introduce. I'm thinking that the tactical benefit of having a reliable motor escape will prove to be well worth the small added drag over the course of a multi-day event.

[Renny[_2_]]

On Saturday, January 7, 2017 at 7:58:33 PM UTC-7, Steve Koerner wrote:
> I side with Bruce. It's pretty obvious to me that FES is the better choice. I believe Bruce left off the most important advantage of FES...
>
> That being the higher inherent reliability of operation. I can't prove it, but my own feeling is that FES would be an order of magnitude more reliable in starting up. And you'll know much more quickly whether it did or did not. The only real downside to FES is the drag that the folded props will introduce. I'm thinking that the tactical benefit of having a reliable motor escape will prove to be well worth the small added drag over the course of a multi-day event.

Steve - Having now flown my LAK-17B FES for 5 years, your "feeling" is dead on. We definitely think alike about the reliability of the FES. After dozens of starts on the ground and in the air, it has never let me down..(knock on wood)! FYI, I am writing an "FES Update" for Soaring magazine, so stay tuned for more info. Thx - Renny

[[email protected]]

We had a member place a similar level of faith in his FES to that shown above, using it to climb away from unlandable terrain. The system powered up and climbed away as advertised - initially. During the climb, the battery overheated and the FES shutdown, as it's designed to do, to protect the battery and ultimately, the aircraft. The pilot was now at moderately low altitude and presented with an unexpected outlanding (startle factor) over terrain that hadn't been assessed for such (complacency / over reliance on FES). A successful outlanding was achieved in that the pilot walked away unharmed. The glider was extensively damaged.

My personal opinion is that electric sustainers are the future and in time, will be the hands down winner when it comes to glider propulsion. That day is yet to arrive because of current limitations in battery technology, namely energy density and safety/reliability.

I have a jet sustainer in my glider which I love but at the same time don't trust. I climb in the vicinity of my chosen & assessed outlanding field until I feel it's safe move on (terrain dependent but usually 1,800ft or so). A friend, knowing I'd flown over an area with a lot of unlandable terrain, once asked "would you go there in a pure glider?". The answer was yes, because I only ever go to places I wouldn't go in a pure glider, preserving glide out to a landable area. The sustainer is an installation of convenience to me, to get me back to my home airfield instead of sitting in a fly blown paddock in the middle of nowhere. It's not a substitute for basic gliding principles and judgement.

CJ

[Renny[_2_]]

On Saturday, January 7, 2017 at 8:54:32 PM UTC-7, wrote:
> We had a member place a similar level of faith in his FES to that shown above, using it to climb away from unlandable terrain. The system powered up and climbed away as advertised - initially. During the climb, the battery overheated and the FES shutdown, as it's designed to do, to protect the battery and ultimately, the aircraft. The pilot was now at moderately low altitude and presented with an unexpected outlanding (startle factor) over terrain that hadn't been assessed for such (complacency / over reliance on FES). A successful outlanding was achieved in that the pilot walked away unharmed. The glider was extensively damaged.
>
> My personal opinion is that electric sustainers are the future and in time, will be the hands down winner when it comes to glider propulsion. That day is yet to arrive because of current limitations in battery technology, namely energy density and safety/reliability.
>
> I have a jet sustainer in my glider which I love but at the same time don't trust. I climb in the vicinity of my chosen & assessed outlanding field until I feel it's safe move on (terrain dependent but usually 1,800ft or so). A friend, knowing I'd flown over an area with a lot of unlandable terrain, once asked "would you go there in a pure glider?". The answer was yes, because I only ever go to places I wouldn't go in a pure glider, preserving glide out to a landable area. The sustainer is an installation of convenience to me, to get me back to my home airfield instead of sitting in a fly blown paddock in the middle of nowhere. It's not a substitute for basic gliding principles and judgement.
>
> CJ

Interesting account and I am sincerely glad your friend walked away. Regardless of the type of sustainer, sound judgement is always critical. Flying over unlandable terrain with the expectation that your sustainer will bail you out, as was seen in this case, was not a wise decision. Whatever system you use, you should always have a "plan B" should it not start.

I do believe the time for electric is now here. We all know that no system is perfect, but the FES does an outstanding job when used in conjunction with common sense. Over 100 gliders now have the FES and many of the major glider manufacturers are offering it as an option. It may not be for everyone, but for many folks the FES is a great option to have. Finally, let's not forget the famous expression....“Don't let the perfect be the enemy of the good.”

If we all wait for "perfect," we will see very little progress in our sport....

[[email protected]]

On Saturday, January 7, 2017 at 7:54:32 PM UTC-8, wrote:


> I have a jet sustainer in my glider which I love but at the same time don't trust. I climb in the vicinity of my chosen & assessed outlanding field until I feel it's safe move on (terrain dependent but usually 1,800ft or so). A friend, knowing I'd flown over an area with a lot of unlandable terrain, once asked "would you go there in a pure glider?". The answer was yes, because I only ever go to places I wouldn't go in a pure glider, preserving glide out to a landable area. The sustainer is an installation of convenience to me, to get me back to my home airfield instead of sitting in a fly blown paddock in the middle of nowhere. It's not a substitute for basic gliding principles and judgement.
>
> CJ

Has it ever failed to start? Is this a JS1?

[Bruce Hoult]

On Sunday, January 8, 2017 at 5:58:33 AM UTC+3, Steve Koerner wrote:
> I side with Bruce. It's pretty obvious to me that FES is the better choice. I believe Bruce left off the most important advantage of FES...
>
> That being the higher inherent reliability of operation. I can't prove it, but my own feeling is that FES would be an order of magnitude more reliable in starting up. And you'll know much more quickly whether it did or did not. The only real downside to FES is the drag that the folded props will introduce. I'm thinking that the tactical benefit of having a reliable motor escape will prove to be well worth the small added drag over the course of a multi-day event.

I assumed that "instant starting" implies that you know right away whether it's going to start or not.

You can safely use this to scratch lower, near a landable area, and pull the trigger much later in your landing approach.

Assuming that it *will* always start 100.000% of the time, and using that assumption to fly low over unlandable areas would be foolish. Things do become disconnected sometimes. If you insist on doing this then at least test it for a few seconds in flight before you start the task! That eliminates many of the bigger risks. But personally I'd always try to have an escape route or landing area available.

[[email protected]]

> Has it ever failed to start? Is this a JS1?

Hi,

It hasn't failed for me yet *touches wood and throws salt over shoulder*. Yes, it's the M&D TJ42 in a JS1.

CJ

[Eric]

On Sat, 7 Jan 2017 19:54:29 -0800 (PST), wrote:

>We had a member place a similar level of faith in his FES to that shown above, using it to climb away from unlandable terrain. The system powered up and climbed away as advertised - initially. During the climb, the battery overheated and the FES shutdown, as it's designed to do, to protect the battery and ultimately, the aircraft. The pilot was now at moderately low altitude and presented with an unexpected outlanding (startle factor) over terrain that hadn't been assessed for such (complacency / over reliance on FES). A successful outlanding was achieved in that the pilot walked away unharmed. The glider was extensively damaged.
>
>My personal opinion is that electric sustainers are the future and in time, will be the hands down winner when it comes to glider propulsion. That day is yet to arrive because of current limitations in battery technology, namely energy density and safety/reliability.
>
>I have a jet sustainer in my glider which I love but at the same time don't trust. I climb in the vicinity of my chosen & assessed outlanding field until I feel it's safe move on (terrain dependent but usually 1,800ft or so). A friend, knowing I'd flown over an area with a lot of unlandable terrain, once asked "would you go there in a pure glider?". The answer was yes, because I only ever go to places I wouldn't go in a pure glider, preserving glide out to a landable area. The sustainer is an installation of convenience to me, to get me back to my home airfield instead of sitting in a fly blown paddock in the middle of nowhere. It's not a substitute for basic gliding principles and judgement.
>
>CJ

The FES system produces 20kw at full power. Most of the gliders
fitted with it will cruise straight and level at about 4-5kw.
Certainly in current versions the system will warm you of a problem
but doesn't shut itself down. I believe the logic is that it is
better to destroy the batteries or motor should the pilot feel that
shutting down will cause a desperate situation. Low voltage or
overheating can generally be cured by reducing the power to cruise
power.

[[email protected]]

>I believe the logic is that it is
>better to destroy the batteries or motor should the pilot feel that
>shutting down will cause a desperate situation.

Hi Eric,

You're right, a quick read of the manual suggests the FES will step through alerts and warnings but it's ultimately the pilot that decides when to shut down. In the case of battery temperature:
- "Batt. Ext. High > 55°C, Stop FES motor!" (red), &
- "Batt. Critical > 75°C, Land immediately!" (red)
The latter suggesting a thermal runaway and/or fire is imminent.

CJ

[Muttley]

Hi all

The new proposed electric 20m Mini Stemme looks an exiting prospect

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

Muttley

[Dan Marotta]

I believe that any emergency system designed to protect equipment should
have a manual override capability. Think of that Airbus flying happily
into the trees while the pilot struggled unsuccessfully to pull up.

Though I have a highly reliable engine in my Stemme, I never fly outside
of gliding distance of a suitable runway. Of course, this limits my
flying in the great southwest somewhat but, having no trailer, there are
plenty of places I could land safely but would not like to take off from.

On 1/7/2017 8:54 PM, wrote:
> We had a member place a similar level of faith in his FES to that shown above, using it to climb away from unlandable terrain. The system powered up and climbed away as advertised - initially. During the climb, the battery overheated and the FES shutdown, as it's designed to do, to protect the battery and ultimately, the aircraft. The pilot was now at moderately low altitude and presented with an unexpected outlanding (startle factor) over terrain that hadn't been assessed for such (complacency / over reliance on FES). A successful outlanding was achieved in that the pilot walked away unharmed. The glider was extensively damaged.
>
> My personal opinion is that electric sustainers are the future and in time, will be the hands down winner when it comes to glider propulsion. That day is yet to arrive because of current limitations in battery technology, namely energy density and safety/reliability.
>
> I have a jet sustainer in my glider which I love but at the same time don't trust. I climb in the vicinity of my chosen & assessed outlanding field until I feel it's safe move on (terrain dependent but usually 1,800ft or so). A friend, knowing I'd flown over an area with a lot of unlandable terrain, once asked "would you go there in a pure glider?". The answer was yes, because I only ever go to places I wouldn't go in a pure glider, preserving glide out to a landable area. The sustainer is an installation of convenience to me, to get me back to my home airfield instead of sitting in a fly blown paddock in the middle of nowhere. It's not a substitute for basic gliding principles and judgement.
>
> CJ

--
Dan, 5J

[[email protected]]

On Saturday, January 7, 2017 at 7:54:32 PM UTC-8, wrote:
> We had a member place a similar level of faith in his FES to that shown above, using it to climb away from unlandable terrain. The system powered up and climbed away as advertised - initially. During the climb, the battery overheated and the FES shutdown, as it's designed to do, to protect the battery and ultimately, the aircraft. The pilot was now at moderately low altitude and presented with an unexpected outlanding (startle factor) over terrain that hadn't been assessed for such (complacency / over reliance on FES). A successful outlanding was achieved in that the pilot walked away unharmed. The glider was extensively damaged.
>
[snip]
> CJ

CJ, can you give us more detail about this incident? This is the first FES failure I've heard of. You said the FES had to be shut down at "moderately low" altitude, which suggests it didn't run for very long. It's surprising that it could overheat so quickly. How long did the FES run before the shutdown? What was the OAT at the time? What altitude MSL did it fail at? Was the battery damaged? Was there any smoke or burning smell? Has the manufacturer or owner inspected the FES system since the incident?

-Ben

[[email protected]]

> CJ, can you give us more detail about this incident? This is the first FES failure I've heard of. You said the FES had to be shut down at "moderately low" altitude, which suggests it didn't run for very long. It's surprising that it could overheat so quickly. How long did the FES run before the shutdown? What was the OAT at the time? What altitude MSL did it fail at? Was the battery damaged? Was there any smoke or burning smell? Has the manufacturer or owner inspected the >FES system since the incident?

Hi Ben,
I wouldn't classify it as a 'failure' as the system worked as advertised. Like any other sustainer (jet, internal combustion, etc) a FES has capacity and operating temperature limitations. These were reached and in accordance with system warnings, the pilot shutdown to prevent damage. To answer your questions (to the best of my knowledge):
- Duration: It had been run previously, hence low capacity and high temp
- Duration immediately before incident: Unknown
- OAT: 86F (approx)
- ALT: Unknown (suspect 2,500AMSL, approx)
- Damage: Nil, it was shutdown in accordance with system warnings. No smoke/smell reported.
- Inspection: Yes. Owner and maintenance provider.

The de-identified summary of the incident is publicly available so I can reproduce it below:

"RUNWAY EXCURSION LAK-19

The pilot was flying cross-country on a weak day and decided to return to the home airfield using the electric sustainer motor. The pilot subsequently flew through lift and decided to continue on task. On return from the turn point the pilot found himself getting low again, so he restarted the electric motor and headed towards some hills in search of lift. Unfortunately, the battery power was low and the motor warning lamp illuminated. The pilot turned off the motor and was immediately faced with an outlanding. While the aircraft was now over hilly terrain with limited landing options, the pilot located a paddock of suitable dimensions with some minor slope. The glider landed at speed and it is suspected that the wheel and starboard wingtip touched the surface simultaneously, resulting in the wing catching in long Lucerne and causing the glider to ground loop. The aircraft was substantially damaged - suffering a bent undercarriage and separation of the starboard wing extension. Pilots of gliders capable of self-retrieving need to fully understand the limitations of their type of motor and must make decisions at sufficient height and with safe landing options available."

Please don't misunderstand the intentions of my post. I'm a fan of the FES in theory and in practice. Personally, I think the next jump in battery technology will push it over the top. It's just that discussions on this topic often include comments on the 'infallibility' of the system. My post was intended to give a real world example of why we still need to apply basic gliding principles to this propulsion type, just like the rest of them.

CJ

[Tony[_5_]]

Yea...Running out of "gas" is no good no matter the propulsion type

[Renny[_2_]]

On Monday, January 9, 2017 at 7:07:34 PM UTC-7, Tony wrote:
> Yea...Running out of "gas" is no good no matter the propulsion type

Indeed...What Tony said!!!

[Dan Marotta]

<snip> It's just that discussions on this topic often include comments
on the 'infallibility' of the system. My post was intended to give a
real world example of why we still need to apply basic gliding
principles to this propulsion type, just like the rest of them.
> CJ

Very well put. It is for just the above reason that, though I have a
very reliable engine, I never get out of range of a safe landing field
and, for me, that means an airport.

--
Dan, 5J

[[email protected]]

Thanks for the additional detail, CJ. The fact that the motor was run previously in the flight changes the picture significantly. However, it's still not clear why the pilot had to shut down the motor. In your original post, you said the battery was overheating, but the incident report says "battery power was low", which suggests the battery voltage had reached it's minimum. Which was it, over-temperature, or under-voltage? These are two very different things. If it was low voltage, then most likely the battery power was simply exhausted. If it was overheating, that suggests a failure of some sort. An OAT of 86F is not extreme, so it would be surprising to me if the battery overheated. Does the FES have any known limitations on motor run-time? My assumption was that it could safely be run continuously until the battery was empty.

I am also a fan of FES and am considering purchasing a sailplane equipped with it. I hope it's not true that the battery could overheat under such seemingly normal operating conditions.

[Dan Marotta]

It would depend on the airfield. I don't mind landing on grass and I'd
even take off from it. Likewise I'd land on gravel in an emergency but
don't want to take off from it out of concern about damage caused by
rocks thrown up by the tires and damage to the carbon prop. I don't
want to land in an unprepared field due to the possibility of nosing
over and the fact that I wouldn't want to take off from a rough field.

Realistically speaking, it's rare to be out of gliding range of a paved
airport except for the leg between Cedar City and Minden. Very lonely
out there...

On 1/10/2017 11:55 AM, Henry wrote:
> Dan Marotta wrote expansively:
>
>> though I have a very reliable engine, I never get out of
>> range of a safe landing field and, for me, that means
>> an airport.
> Won't an airfield do?

--
Dan, 5J

[Bob Kuykendall]

On Tuesday, January 10, 2017 at 8:50:49 AM UTC-8, wrote:
> ...Which was it, over-temperature, or under-voltage? These are two very different things.

Not necessarily. I=V/R says that as the battery voltage goes down, the amperage required for specific power level is greater. So when you have a computer-controlled system trying to maintain a commanded power level by regulating current upwards, you can get a situation where low voltage is the direct cause of overheating of specific parts of the system.

Full disclosure: I'm not an FES expert, but I am an FES reseller.

--Bob K.

[Tony[_5_]]

On Tuesday, January 10, 2017 at 10:50:49 AM UTC-6, wrote:
> Thanks for the additional detail, CJ. The fact that the motor was run previously in the flight changes the picture significantly. However, it's still not clear why the pilot had to shut down the motor. In your original post, you said the battery was overheating, but the incident report says "battery power was low", which suggests the battery voltage had reached it's minimum. Which was it, over-temperature, or under-voltage? These are two very different things. If it was low voltage, then most likely the battery power was simply exhausted. If it was overheating, that suggests a failure of some sort. An OAT of 86F is not extreme, so it would be surprising to me if the battery overheated. Does the FES have any known limitations on motor run-time? My assumption was that it could safely be run continuously until the battery was empty.
>
> I am also a fan of FES and am considering purchasing a sailplane equipped with it. I hope it's not true that the battery could overheat under such seemingly normal operating conditions.

My experience self launching the Silent 2 Electro is that Battery temperature has never been an issue. I have once or twice gotten a yellow warning for the motor temp when launching in Uvalde and Kansas on 100ish degF days. Slightly "throttling back" cured that with no issue. Finding a thermal helps a lot too.

The power consumption when cruising level is very low and motor temps have never been a problem at all when i've had to cruise on hot days. One of those days was a fairly long cruise in Lithuania where I ran the motor for about 35 minutes: http://www.onlinecontest.org/olc-2.0/gliding/flightinfo.html?flightId=495576510

[[email protected]]

The bottom line: Did the FES overheat before the battery was exhausted? CJ, can you give us an answer?

[[email protected]]

Hi Ben,

Sometimes work has to come befor gliding (and RAS). An abhorrent thought, I know ;)

I apologize for the ambiguity but battery temperature leading to shutdown was the reason given to me by an individual involved in the incident review. However, that's not to say the situation wasn't misunderstood. Thus, the only way to be sure is to ask the pilot himself which I'm happy to do but that will take time as we're not expected to catch up for a while. If you reply with the portion of your email address that's between the 'hir' and the @ I'll email you his response.

FES are very open with their documentation. Have you reviewed their manuals? Available at http://www.front-electric-sustainer.com/download.php , they specify the temperature limitations for motor and battery, among others. Note that the level to shutdown the system to prevent battery damage occurs prior to battery exhaustion.

CJ

[[email protected]]

Thanks, CJ. The FCU manual states that temperature is monitored for each battery pack, the motor, and motor controller. It's possible any one of them overheated. There's no rush, but if you could get more detail from the pilot, that would be great. Please post it here so others can benefit as well.