Ventus 2cxa with FES

[LZ design]

Some photos from 1st public presentation of Ventus 2cxa with FES during Aero 2014

https://picasaweb.google.com/115479415730905646727/AERO20141stPresentationOfVentus2cxaFES?noredirect= 1

Regards,

Luka

[Mike the Strike]

Well, that answers the question of how to fit the FES to a glider with a non-circular nose section, like the Discus and Ventus!

I wonder who the intended buyer is, though. Avid racers won't like the extra drag and those attracted to self-launchers won't have enough power. Are there enough folks like me who fly a fair amount of cross-country and who like the idea of a reliable sustainer?

Mike

[Andy K]

On Monday, April 14, 2014 5:04:28 PM UTC-4, Mike the Strike wrote:
> Well, that answers the question of how to fit the FES to a glider with a non-circular nose section, like the Discus and Ventus!
>
>
>
> I wonder who the intended buyer is, though. Avid racers won't like the extra drag and those attracted to self-launchers won't have enough power. Are there enough folks like me who fly a fair amount of cross-country and who like the idea of a reliable sustainer?
>
>
>
> Mike

This is a big prop. I wonder if they tried to self launch it. I bet the engine is powerful enough and it is all about battery capacity.

[Ramy[_2_]]

On Monday, April 14, 2014 2:04:28 PM UTC-7, Mike the Strike wrote:
> Well, that answers the question of how to fit the FES to a glider with a non-circular nose section, like the Discus and Ventus!
>
>
>
> I wonder who the intended buyer is, though. Avid racers won't like the extra drag and those attracted to self-launchers won't have enough power. Are there enough folks like me who fly a fair amount of cross-country and who like the idea of a reliable sustainer?
>
>
>
> Mike

I would be interested to know if it can be fitted into an ASW27.

Ramy

[Mike the Strike]

I suspect that there's not enough ground clearance to self-launch, but a vehicle launch to modest height plus a climb out on the electric motor might work (some weaker self-launchers use this technique, especially at high density altitudes).

No doubt the developers will let us know!

Mike

[Greg Arnold]

I wonder if they are using the CG tow hook, or if they have installed a
hook forward of that. I thought that you couldn't have a new glider
with only a CG hook in Europe.




On 4/14/2014 2:13 PM, Andy K wrote:
> On Monday, April 14, 2014 5:04:28 PM UTC-4, Mike the Strike wrote:
>> Well, that answers the question of how to fit the FES to a glider with a non-circular nose section, like the Discus and Ventus!
>>
>>
>>
>> I wonder who the intended buyer is, though. Avid racers won't like the extra drag and those attracted to self-launchers won't have enough power. Are there enough folks like me who fly a fair amount of cross-country and who like the idea of a reliable sustainer?
>>
>>
>>
>> Mike
>
> This is a big prop. I wonder if they tried to self launch it. I bet the engine is powerful enough and it is all about battery capacity.
>

[Steve Koerner]

From a competition pilot point of view there would have to be a small drag penalty and a weight penalty. But both of those would seem to be pretty small in comparison to the competitive benefit that arises from the ability to stick to the course line and never have to be distracted by the need to deviate towards a landing option. I don't have experience to know, but I'm suspecting that the reliability of the FES might be sufficient that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting? You certainly can't do that with a gas engine.

[Wolf Aviator[_2_]]

At 00:10 15 April 2014, Steve Koerner wrote:
>From a competition pilot point of view there would have to be a
small drag
>=
>penalty and a weight penalty. But both of those would seem
to be pretty
>sm=
>all in comparison to the competitive benefit that arises from the
ability
>t=
>o stick to the course line and never have to be distracted by
the need to
>d=
>eviate towards a landing option. I don't have experience to
know, but I'm
>=
>suspecting that the reliability of the FES might be sufficient
that one
>cou=
>ld drive it straight into the boonies then flip the switch only at
the
>last=
> minute -- wouldn't that be exciting? You certainly can't do
that with a
>g=
>as engine.
>

But if you are 100km away from your airfield, especially if you
used your battery for take off, there will be little or no use of
FES.
I like the idea, but sorry, with current Li-ion batteries with max
150Wh/kg, this is not very promising technology. I am waiting for
Li-S, or Li-Air cells, then we can talk seriously about FES.
Regards
Wolf
http://youtu.be/WCej1kZInZk

[Renny[_2_]]

As the saying goes....

"The perfect is the enemy of the good..."

There is no "perfect," but I do believe the FES is a tremendous technical advancement which can really add to one's soaring safety and enjoyment.

I have been very fortunate to own a LAK-17B FES for the past two years and it is truly an outstanding ship with a very reliable sustainer. I do take aero tows, so I get to save every "volt" in the event I need to use the FES for a self retrieve. If it is needed the FES can get me home or at least to an airport and the maximum range of up to 100KM works out just fine. Also, as battery technology improves, new batteries can be installed and the range of the FES will also improve. I can wait for those future battery improvement, but the FES design has been around for five years and IMHO, is a proven design. After over 40 years in soaring, I was not going to wait for the "perfect..."

Now, if one wants a self-launcher the FES is probably not the right choice (unless one wants to go with the FES in a lighter glider like the Silent 2 Electro), but for a sustainer, the FES is truly is an excellent solution!

Now, be safe out there!
Thanks - Renny




On Monday, April 14, 2014 6:26:24 PM UTC-6, Wolf Aviator wrote:
> At 00:10 15 April 2014, Steve Koerner wrote:
>
> >From a competition pilot point of view there would have to be a
>
> small drag
>
> >=
>
> >penalty and a weight penalty. But both of those would seem
>
> to be pretty
>
> >sm=
>
> >all in comparison to the competitive benefit that arises from the
>
> ability
>
> >t=
>
> >o stick to the course line and never have to be distracted by
>
> the need to
>
> >d=
>
> >eviate towards a landing option. I don't have experience to
>
> know, but I'm
>
> >=
>
> >suspecting that the reliability of the FES might be sufficient
>
> that one
>
> >cou=
>
> >ld drive it straight into the boonies then flip the switch only at
>
> the
>
> >last=
>
> > minute -- wouldn't that be exciting? You certainly can't do
>
> that with a
>
> >g=
>
> >as engine.
>
> >
>
>
>
> But if you are 100km away from your airfield, especially if you
>
> used your battery for take off, there will be little or no use of
>
> FES.
>
> I like the idea, but sorry, with current Li-ion batteries with max
>
> 150Wh/kg, this is not very promising technology. I am waiting for
>
> Li-S, or Li-Air cells, then we can talk seriously about FES.
>
> Regards
>
> Wolf
>
> http://youtu.be/WCej1kZInZk

[[email protected]]

Dne ponedeljek, 14. april 2014 23:13:19 UTC+2 je oseba Andy K napisala:
> On Monday, April 14, 2014 5:04:28 PM UTC-4, Mike the Strike wrote:
>
> > Well, that answers the question of how to fit the FES to a glider with a non-circular nose section, like the Discus and Ventus!
>
> >
>
> >
>
> >
>
> > I wonder who the intended buyer is, though. Avid racers won't like the extra drag and those attracted to self-launchers won't have enough power. Are there enough folks like me who fly a fair amount of cross-country and who like the idea of a reliable sustainer?
>
> >
>
> >
>
> >
>
> > Mike
>
>
>
> This is a big prop. I wonder if they tried to self launch it. I bet the engine is powerful enough and it is all about battery capacity.

You are right, we made a bigger chord of the blade, in order to load motor more. We expect about 26kW of max power, which will be enough even for selflaunch. Battery compartment is designed in a way so that there will be a possibility to install bigger battery pack, which will allow range of 180km of level flight or altitude gain of 2000m!

[[email protected]]

Dne torek, 15. april 2014 00:19:29 UTC+2 je oseba Mike the Strike napisala:
> I suspect that there's not enough ground clearance to self-launch, but a vehicle launch to modest height plus a climb out on the electric motor might work (some weaker self-launchers use this technique, especially at high density altitudes).
>
>
>
> No doubt the developers will let us know!
>
>
>
> Mike

There is enough ground clearence for a selflaunch from concrete runway or smooth grass.

[[email protected]]

Dne torek, 15. april 2014 01:11:27 UTC+2 je oseba Greg Arnold napisala:
> I wonder if they are using the CG tow hook, or if they have installed a
>
> hook forward of that. I thought that you couldn't have a new glider
>
> with only a CG hook in Europe.

There is a suitable space for a front hook below instrument panel, where is usualy located front battery. This battery is not required anymore.

Regards,

Luka

[[email protected]]

Dne torek, 15. april 2014 02:10:45 UTC+2 je oseba Steve Koerner napisala:
> From a competition pilot point of view there would have to be a small drag penalty and a weight penalty. But both of those would seem to be pretty small in comparison to the competitive benefit that arises from the ability to stick to the course line and never have to be distracted by the need to deviate towards a landing option. I don't have experience to know, but I'm suspecting that the reliability of the FES might be sufficient that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting? You certainly can't do that with a gas engine.

You are right, at FES you can start engine last minute (1 second to full power), and it is exciting. Totaly different way of flying!

Regards,

Luka

[[email protected]]

Dne torek, 15. april 2014 02:26:24 UTC+2 je oseba Wolf Aviator napisala:
> At 00:10 15 April 2014, Steve Koerner wrote:
>
> >From a competition pilot point of view there would have to be a
>
> small drag
>
> >=
>
> >penalty and a weight penalty. But both of those would seem
>
> to be pretty
>
> >sm=
>
> >all in comparison to the competitive benefit that arises from the
>
> ability
>
> >t=
>
> >o stick to the course line and never have to be distracted by
>
> the need to
>
> >d=
>
> >eviate towards a landing option. I don't have experience to
>
> know, but I'm
>
> >=
>
> >suspecting that the reliability of the FES might be sufficient
>
> that one
>
> >cou=
>
> >ld drive it straight into the boonies then flip the switch only at
>
> the
>
> >last=
>
> > minute -- wouldn't that be exciting? You certainly can't do
>
> that with a
>
> >g=
>
> >as engine.
>
> >
>
>
>
> But if you are 100km away from your airfield, especially if you
>
> used your battery for take off, there will be little or no use of
>
> FES.
>
> I like the idea, but sorry, with current Li-ion batteries with max
>
> 150Wh/kg, this is not very promising technology. I am waiting for
>
> Li-S, or Li-Air cells, then we can talk seriously about FES.
>
> Regards
>
> Wolf
>
> http://youtu.be/WCej1kZInZk

As mentined above already at Ventus we have enough margin of max weight of non lifting parts, so that we were able to integrate bigger battery compartment box, so that we can fit inside bigger battery packs (50kg instead of standard 32kg). Range of 180km of level flight or 2000m altitude gain is more than sufficient!

Regards,

Luka

[Ramy[_2_]]

Luka, can it be installed on a Schleicher, in particular ASW27?

Ramy

[jfitch]

On Monday, April 14, 2014 5:10:45 PM UTC-7, Steve Koerner wrote:
> From a competition pilot point of view there would have to be a small drag penalty and a weight penalty. But both of those would seem to be pretty small in comparison to the competitive benefit that arises from the ability to stick to the course line and never have to be distracted by the need to deviate towards a landing option. I don't have experience to know, but I'm suspecting that the reliability of the FES might be sufficient that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting? You certainly can't do that with a gas engine.

" that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting?"

Deadly exciting, actually....

[[email protected]]

Dne torek, 15. april 2014 19:18:18 UTC+2 je oseba Ramy napisala:
> Luka, can it be installed on a Schleicher, in particular ASW27?
>
>
>
> Ramy

From techical point of view, I am sure we could find a solution. However in Europe under EASA is currently not possible, if there is no support from holder of Type Certificate. For USA under experimental might be possible, but we need a glider in our workshop for retrofit.

Regards,

Luka

[Steve Koerner]

On Tuesday, April 15, 2014 11:41:22 AM UTC-7, jfitch wrote:
> On Monday, April 14, 2014 5:10:45 PM UTC-7, Steve Koerner wrote:
>
> > From a competition pilot point of view there would have to be a small drag penalty and a weight penalty. But both of those would seem to be pretty small in comparison to the competitive benefit that arises from the ability to stick to the course line and never have to be distracted by the need to deviate towards a landing option. I don't have experience to know, but I'm suspecting that the reliability of the FES might be sufficient that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting? You certainly can't do that with a gas engine.
>
>
>
> " that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting?"
>
>
>
> Deadly exciting, actually....

I sort of figured someone would snipe to that effect. So, jfitch, what is your reasoning that makes it 'deadly'?

Are there any known cases when an FES was intended to be initiated but failed to do so in flight?

It would seem to me that the FES has much going for it in terms of its potential for very high reliable operation. That would be the fact of no boom to raise and the fact that the power plant is an electric motor.

Single engine airplane pilots think nothing of routinely flying in the boonies with no landing alternate available to them. That contrasts with an FES glider pilot who might put himself into that situation only rarely.

I think all of us have had plenty of experience with both electric motors and gas motors and know the former to be vastly more reliable. Yet power pilots treat their gas engines as reliable enough to bet their life on. I'm suspecting that a reasoned glider pilot who has tested his FES startup many times in non-threatening circumstances would arrive at the same determination. The interesting part is that yields a significant advantage in competition.

[Kevin Neave[_2_]]

From a general flying point of view, here in the UK we're never really that
far from an airfield.
The "limited" range still means you can get away from a Farmer's field to a
true airfield where the reception is likely to be better & chance of
breaking the glider much reduced.
As a Discus Turbo owner I'm very aware of the failure rate (mostly pilot
induced) of the current turbos.
I can't believe any electric sustainer could be less reliable

FES certainly appeals to me

Regards

KN

[[email protected]]

On Tuesday, April 15, 2014 12:04:43 PM UTC-7, wrote:
> Dne torek, 15. april 2014 19:18:18 UTC+2 je oseba Ramy napisala:
>
> > Luka, can it be installed on a Schleicher, in particular ASW27?
>
> >
>
> >
>
> >
>
> > Ramy
>
>
>
> From techical point of view, I am sure we could find a solution. However in Europe under EASA is currently not possible, if there is no support from holder of Type Certificate. For USA under experimental might be possible, but we need a glider in our workshop for retrofit.
>
>
>
> Regards,
>
>
>
> Luka

If you ever happen to get a Ventus B in your shop and install one of these in it, it would open up a whole new world to many folks with older gliders! Especially if the conversion could then be done by qualified repair shops around the world (including U.S.A.). If that could ever be a possibility, I wonder what the cost might be. This thread certainly has opened up ideas that so far have been mostly in dreams for many pilots.

Bob

[jfitch]

On Tuesday, April 15, 2014 1:32:16 PM UTC-7, Steve Koerner wrote:
> On Tuesday, April 15, 2014 11:41:22 AM UTC-7, jfitch wrote:
>
> > On Monday, April 14, 2014 5:10:45 PM UTC-7, Steve Koerner wrote:
>
> >
>
> > > From a competition pilot point of view there would have to be a small drag penalty and a weight penalty. But both of those would seem to be pretty small in comparison to the competitive benefit that arises from the ability to stick to the course line and never have to be distracted by the need to deviate towards a landing option. I don't have experience to know, but I'm suspecting that the reliability of the FES might be sufficient that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting? You certainly can't do that with a gas engine.
>
> >
>
> >
>
> >
>
> > " that one could drive it straight into the boonies then flip the switch only at the last minute -- wouldn't that be exciting?"
>
> >
>
> >
>
> >
>
> > Deadly exciting, actually....
>
>
>
> I sort of figured someone would snipe to that effect. So, jfitch, what is your reasoning that makes it 'deadly'?
>
>
>
> Are there any known cases when an FES was intended to be initiated but failed to do so in flight?
>
>
>
> It would seem to me that the FES has much going for it in terms of its potential for very high reliable operation. That would be the fact of no boom to raise and the fact that the power plant is an electric motor.
>
>
>
> Single engine airplane pilots think nothing of routinely flying in the boonies with no landing alternate available to them. That contrasts with an FES glider pilot who might put himself into that situation only rarely.
>
>
>
> I think all of us have had plenty of experience with both electric motors and gas motors and know the former to be vastly more reliable. Yet power pilots treat their gas engines as reliable enough to bet their life on. I'm suspecting that a reasoned glider pilot who has tested his FES startup many times in non-threatening circumstances would arrive at the same determination. The interesting part is that yields a significant advantage in competition.

While an electric motor *may* be more reliable than gas, you are still starting a stopped motor, unfolding a folded prop, etc. I don't know a single power plane pilot who would knowingly fly into rocks or over water *with the engine stopped*, figuring on starting it when the trees got close.

This has been proposed endlessly as an advantage motor gliders have over pure gliders, the ability to fly low over unlandable terrain. I don't fly mine that way and I don't know of anyone that does. My engine starts are always over a landable field, the advantage is that the inconvenience of a ground retrieve is eliminated in most cases.

Now, there are competition pilots who will willingly fly over unlandable terrain with no motor at all, just as there are those that will cheat in various ways. Such a pilot might abuse the capability. It seems to be rarely said that one of the reasons many pilots do not engage in competition is that risk is rewarded.

[[email protected]]

>jfitch
> Now, there are competition pilots who will willingly fly over unlandable terrain with no motor at all, just as there are those that will cheat in various ways. Such a pilot might abuse the capability. It seems to be rarely said that one of the reasons many pilots do not engage in competition is that risk is rewarded.

Jon
I question your statement about unlandable terrain. The very few racers that might have flown over unlandable terrain without a safe glide cushion are either not with us any more, or have broken a glider. Never have they been rewarded. Brains and technique are rewarded.

The benefit I see to a sustainer is getting home early and avoiding a long retrieve. This can be significant in a long nationals or world comp.

Regards
Richard Walters

[Steve Koerner]

I can understand that a pilot who flies a gas engine motorglider and who's steeped in its appropriate use would want to extrapolate his know-how to the electric FES. The question is whether or not the FES could be sufficiently more reliable in its one second startup process that the old rules of safe motorgliding don't apply. To me, that seems like a good possibility. Time will tell.

Separately, I don't agree that glider competition is about being rewarded for risk.

[GC[_2_]]

On 16/04/2014 06:32, Steve Koerner wrote:

> I sort of figured someone would snipe to that effect. So, jfitch,
> what is your reasoning that makes it 'deadly'?
>
> Are there any known cases when an FES was intended to be initiated
> but failed to do so in flight?

Nice straw man. Are you claiming that means it'll never happen? Do you
write TV ads for a living?

> It would seem to me that the FES has much going for it in terms of
> its potential for very high reliable operation. That would be the
> fact of no boom to raise and the fact that the power plant is an
> electric motor.

No question.

> Single engine airplane pilots think nothing of routinely flying in
> the boonies with no landing alternate available to them. That
> contrasts with an FES glider pilot who might put himself into that
> situation only rarely.

There is a major difference. A certificated light aircraft has to have
a certificated engine meeting known standards of reliability in design,
construction and maintenance. EVERY powered glider's engine is only
certified as an auxiliary and meets almost none of the certified
engine's reliability tests.

To reprise what I said earlier about PLBs vs Spot/Inreach: a certified
engine is the real thing, the engine in a powered glider is a nice toy -
even electric ones.

> I think all of us have had plenty of experience with both electric
> motors and gas motors and know the former to be vastly more reliable.
> Yet power pilots treat their gas engines as reliable enough to bet
> their life on. I'm suspecting that a reasoned glider pilot who has
> tested his FES startup many times in non-threatening circumstances
> would arrive at the same determination. The interesting part is that
> yields a significant advantage in competition.

Go ahead. Bet your life on it!

GC

[Alexander Georgas[_2_]]

As glider pilots, whether powered or not, we always fly with a question
in our mind: where should I land if I needed to land now?

From an engineering perspective it could probably be possible to build
an electric motor system that would start with a reliability that would
satisfy the statistics of an operational retrieve system, not an
auxiliary one. What is anyone's guess is whether it is financially
viable to do so at the moment.

The clue would be in the manual of a certified FES glider, where it says
"engine operation". Does it recommend having a field available, does it
state a minimum altitude for starts?

Until then, all bets are off on whether a motor in a glider will start,
electric or not.

Alexander

On 16/04/2014 07:53, GC wrote:
> On 16/04/2014 06:32, Steve Koerner wrote:
>
>> I sort of figured someone would snipe to that effect. So, jfitch,
>> what is your reasoning that makes it 'deadly'?
>>
>> Are there any known cases when an FES was intended to be initiated
>> but failed to do so in flight?
>
> Nice straw man. Are you claiming that means it'll never happen? Do you
> write TV ads for a living?
>
>> It would seem to me that the FES has much going for it in terms of
>> its potential for very high reliable operation. That would be the
>> fact of no boom to raise and the fact that the power plant is an
>> electric motor.
>
> No question.
>
>> Single engine airplane pilots think nothing of routinely flying in
>> the boonies with no landing alternate available to them. That
>> contrasts with an FES glider pilot who might put himself into that
>> situation only rarely.
>
> There is a major difference. A certificated light aircraft has to have
> a certificated engine meeting known standards of reliability in design,
> construction and maintenance. EVERY powered glider's engine is only
> certified as an auxiliary and meets almost none of the certified
> engine's reliability tests.
>
> To reprise what I said earlier about PLBs vs Spot/Inreach: a certified
> engine is the real thing, the engine in a powered glider is a nice toy -
> even electric ones.
>
>> I think all of us have had plenty of experience with both electric
>> motors and gas motors and know the former to be vastly more reliable.
>> Yet power pilots treat their gas engines as reliable enough to bet
>> their life on. I'm suspecting that a reasoned glider pilot who has
>> tested his FES startup many times in non-threatening circumstances
>> would arrive at the same determination. The interesting part is that
>> yields a significant advantage in competition.
>
> Go ahead. Bet your life on it!
>
> GC
>
>

[[email protected]]

> I question your statement about unlandable terrain. The very few racers that might have flown over unlandable terrain without a safe glide cushion are either not with us any more, or have broken a glider. Never have they been rewarded. Brains and technique are rewarded.
>
> The benefit I see to a sustainer is getting home early and avoiding a long retrieve. This can be significant in a long nationals or world comp.
>
> Regards
>
> Richard Walters

Rick's spot on here. However, races are, today, often won by low saves over good landable fields. Whether that is a good idea or whether we should put an end to this fact with a hard deck is a discussion for a later day. The fact is, climbing out from 500 feet (or less, let's admit it) has won many a contest.

A disadvantage of current sustainers is that to be at all safe you have to start the engine process at 1000' or more -- over a good field of course. A sustainer where you push one button at 500 feet when you're normally committing to land, no big drag inducing pylon goes up, and you know in a second if it works or not, and proceed either to climb out or to focus entirely on the landing, would be important in contest soaring.

Too bad the props look draggy, and batteries are still pretty heavy ways to store energy. A hybrid or fuel cell would seem to offer the best of both worlds

John Cochrane

[[email protected]]

Luka of LZ Design,
If there were a FES retrofit kit for my Hph 304CZ, I'd be the first in line to get it done. The FES, in my opinion, is the wave of the future in Soaring.
Chuck Zabinski

[jfitch]

On Tuesday, April 15, 2014 7:49:02 PM UTC-7, wrote:
> >jfitch
>
> > Now, there are competition pilots who will willingly fly over unlandable terrain with no motor at all, just as there are those that will cheat in various ways. Such a pilot might abuse the capability. It seems to be rarely said that one of the reasons many pilots do not engage in competition is that risk is rewarded.
>
>
>
> Jon
>
> I question your statement about unlandable terrain. The very few racers that might have flown over unlandable terrain without a safe glide cushion are either not with us any more, or have broken a glider. Never have they been rewarded. Brains and technique are rewarded.
>
>
>
> The benefit I see to a sustainer is getting home early and avoiding a long retrieve. This can be significant in a long nationals or world comp.
>
>
>
> Regards
>
> Richard Walters

Rick,

In an Idea World, only brains and technique would be rewarded. But in This World, we find it necessary to have (for example) minimum finish rules, rules against cloud flying, at least the discussion of rules to prevent low saves - all because the reward (in many competitor's minds) outweighs the risk. Over the long haul, those who's risk tolerance exceeds their ability (or luck) pay a price. But there are plenty of competitors flying with some very high historical repair bills to prove my point. The fact that Steve even suggests what he did is further evidence.

The technology exists to eliminate most of this by creating a terrain map guaranteeing safe gliding altitude to a landable field, dropping below which would be severely penalized or DSQ'd. However I think most competitors don't like the idea because it eliminates their ability to judge what risks to take. It would mitigate Steve's concern about motor gliders though, and might bring some of the lurkers into active competition.

Jon

[jfitch]

On Tuesday, April 15, 2014 7:49:02 PM UTC-7, wrote:
> >jfitch
>
> > Now, there are competition pilots who will willingly fly over unlandable terrain with no motor at all, just as there are those that will cheat in various ways. Such a pilot might abuse the capability. It seems to be rarely said that one of the reasons many pilots do not engage in competition is that risk is rewarded.
>
>
>
> Jon
>
> I question your statement about unlandable terrain. The very few racers that might have flown over unlandable terrain without a safe glide cushion are either not with us any more, or have broken a glider. Never have they been rewarded. Brains and technique are rewarded.
>
>
>
> The benefit I see to a sustainer is getting home early and avoiding a long retrieve. This can be significant in a long nationals or world comp.
>
>
>
> Regards
>
> Richard Walters

Rick,

In an Ideal World, brains and technique would be the only thing rewarded. In This World, we find it necessary to have (for example) minimum finish altitude rules, rules against cloud flying, at least the discussion of rules limiting low saves - all directed at limiting the advantage of risk taking. Long term, pilots who take more risk than their skill (or luck) can manage pay a price. But there are certainly enough competition pilots with large historical repair bills to prove my point. Steve even suggesting what he did is further evidence.

The technology exists today to eliminate much of this by creating a terrain map guaranteeing a safe glide slope to a landable field, below which there would be withering penalties or a DSQ. But many competition pilots will be against the idea, because it limits their own free will about what risks to take. I believe it would have the effect of luring some of the lurkers into active competition though, because in large measure the amount of risk taken would be flattened - leaving only skill and technique.

Jon

[Paul T[_4_]]

How does FES compare with the jet turbo's? I know the Shark and JS1 have a
more powerfull jet than the 'jet Ventus 2'. Are they a better or worse
option?

[[email protected]]

Dne ponedeljek, 14. april 2014 22:17:13 UTC+2 je oseba LZ design napisala:
> Some photos from 1st public presentation of Ventus 2cxa with FES during Aero 2014
>
>
>
> https://picasaweb.google.com/115479415730905646727/AERO20141stPresentationOfVentus2cxaFES?noredirect= 1
>
>
>
> Regards,
>
>
>
> Luka

I read a comments with interest. It is a matter of good airmanship to have at least some options always available where you can land a glider.
But it is true that at FES there is no additional drag of extended pylon, and so you always have performance of pure glider at least, so more time to decide.
Additionally we have very good reliability statistic with FES. So far as I am informed nobody landed on the field due to the reason, that FES did not start. Actually when you switch ON power switch, and get green LED, and "Controller ready" message on the screen, pilot can be 99% sure that motor will start. There is no engine which would be 100% reliable, but I think FES is close to that.
Before each flight pilot needs to perform a short test run, in order to be sure that all is OK. If there is any problem in the system, is then showed already.
For comparison with existing sustainers with Solo 2350 engine, which require windmiling and decompressor, is pretty difficult and also dangerous to perform a test run on the ground, as it works only at full power. So pilot do not have any idea if the system will start until he is on 200m trying to start it. And the worse thing is that pilot needs to push a stick forward to get some speed, but when you are already low, this is not action somebody would appreciate to perform...
Those pilots who are flying with FES equipped gliders, already know the difference. Regarding the range: existing battery packs are more than sufficient for what average glider pilot really needs. You can read in book of Sebastian Kawa on page 88:
"I really would happily fly a glider which has a reliable engine that starts up quickly. It would only need to run for 15 minutes or so; it wouldn't have to get me back to the airfield, just help me to return to safer place."
And FES is just this, and much more!
I suggest you to read also text in his book on page 222 and 223 about Kawa's experiance with Solo sustainer engine.

Regards,

Luka

[son_of_flubber]

I have a question about the history of soaring... (I'm not asking a practical serious question.)

Has anyone tried and/or had any luck with a 'slow burn single use' solid rocket in a glider? It would have the advantage of high energy density, low drag and quick start. I suppose that it might melt something important if it were were mounted on the fuselage. What about a wing mount close to the root?

I know this idea sounds crazy, but a pop-up jet sustainer strikes me as only slightly less outrageous.

[Mike the Strike]

On Wednesday, April 16, 2014 2:01:28 PM UTC-7, wrote:
> Dne ponedeljek, 14. april 2014 22:17:13 UTC+2 je oseba LZ design napisala:
>
> > Some photos from 1st public presentation of Ventus 2cxa with FES during Aero 2014
>
> >
>
> >
>
> >
>
> > https://picasaweb.google.com/115479415730905646727/AERO20141stPresentationOfVentus2cxaFES?noredirect= 1
>
> >
>
> >
>
> >
>
> > Regards,
>
> >
>
> >
>
> >
>
> > Luka
>
>
>
> I read a comments with interest. It is a matter of good airmanship to have at least some options always available where you can land a glider.
>
> But it is true that at FES there is no additional drag of extended pylon, and so you always have performance of pure glider at least, so more time to decide.
>
> Additionally we have very good reliability statistic with FES. So far as I am informed nobody landed on the field due to the reason, that FES did not start. Actually when you switch ON power switch, and get green LED, and "Controller ready" message on the screen, pilot can be 99% sure that motor will start. There is no engine which would be 100% reliable, but I think FES is close to that.
>
> Before each flight pilot needs to perform a short test run, in order to be sure that all is OK. If there is any problem in the system, is then showed already.
>
> For comparison with existing sustainers with Solo 2350 engine, which require windmiling and decompressor, is pretty difficult and also dangerous to perform a test run on the ground, as it works only at full power. So pilot do not have any idea if the system will start until he is on 200m trying to start it. And the worse thing is that pilot needs to push a stick forward to get some speed, but when you are already low, this is not action somebody would appreciate to perform...
>
> Those pilots who are flying with FES equipped gliders, already know the difference. Regarding the range: existing battery packs are more than sufficient for what average glider pilot really needs. You can read in book of Sebastian Kawa on page 88:
>
> "I really would happily fly a glider which has a reliable engine that starts up quickly. It would only need to run for 15 minutes or so; it wouldn't have to get me back to the airfield, just help me to return to safer place."
>
> And FES is just this, and much more!
>
> I suggest you to read also text in his book on page 222 and 223 about Kawa's experiance with Solo sustainer engine.
>
>
>
> Regards,
>
>
>
> Luka

Indeed, we have that very problem in southern Arizona. Many of our emergency landing spots are less than desirable (dirt strips on the wrong side of the mountains requiring a long arduous road retrieve, or smugglers landing spots near the border where you are likely to meet with armed villains). You can land safely there (as I have done), but the retrieve will be long and not much fun.

A modest self-retrieval of 50 km or so will get us to a town with a decent airfield with the possibility of an aero retrieve or, at worst, dinner and a bed for the night! It might even get us final glide home.

Mike

[Wolf Aviator[_2_]]

At 22:31 16 April 2014, son_of_flubber wrote:
>I have a question about the history of soaring... (I'm not
asking a
>practic=
>al serious question.)
>
>Has anyone tried and/or had any luck with a 'slow burn
single use' solid
>ro=
>cket in a glider? It would have the advantage of high
energy density, low
>=
>drag and quick start. I suppose that it might melt
something important if
>=
>it were were mounted on the fuselage. What about a
wing mount close to
>the=
> root?
>
>I know this idea sounds crazy, but a pop-up jet sustainer
strikes me as
>onl=
>y slightly less outrageous.
>
>

Germans did Me-163. I know that it had not an 'slow burn'
solid rocket, but it was liquid fuel, but still it was glider
with rocket engine :)


Regards
Wolf
http://youtu.be/WCej1kZInZk

[Steve Koerner]

Well, I've taken a lot of heat for my suggestion. That's really how it should be when someone publishes a suggestion that's outside the norms of established safety practice. Reality is that I don't have an FES glider and if I had one I'd likely treat it quite conservatively for a long time. Getting bolder with its use would only happen if my own accumulation of experience as well as the experience of others had taught me that it was safe to do so.

Consider, though, that terrain isn't black and white, landable and unlandable; Landability is a matter of degree. Certain boulder strewn terrain would probably kill you whereas a rough pasture might take out your gear at worst. A road landing option or a narrow airstrip option might work but might send you on a ground loop. So along the spectrum of 'unlandable terrain' there would almost certainly exist a range of possibilities for the late use of FES. The reasonableness of that option is related to the strength of one's expectation that the motor will start in relation to the likely consequences if it doesn't. Luka's quote from Kawa reflects that notion.

[Chris Nicholas[_2_]]

I had the first FES in the UK in 2011. It has always operated OK when operated correctly, but statistically that is not over very many flights. I did mismanage it a couple of times in the first week, due to misunderstanding a safety interlock - the manual has since been changed to help avoid that mistake.

I do not fly over totally unlandable terrain in southern England - though I have in mountainous Scotland, where I try to keep high enough always to reach landable lowlands. Large parts of England are, however, almost unlandable because of growing crops from May to July. I am happy to fly over them relying upon a mixture of experience (there are usually, though infrequent, landable options here and there), acceptable risk (a landing in crop is risky to the glider but should be risk free to pilot - been there, done it), and FES as a last resort.

It has transformed my gliding to an extent, freeing me from need for retrieve crews and avoiding landouts which were increasingly difficult because of medical issues for me.

I have also avoided relights when failing quickly to find a thermal after a winch launch - I just switch the motor on for a few minutes.

I would not like to be without it.

Just my 2p'th. Ymmv.

Chris N

[Steve Leonard[_2_]]

On Wednesday, April 16, 2014 5:31:37 PM UTC-5, son_of_flubber wrote:
> I have a question about the history of soaring... (I'm not asking a practical serious question.) Has anyone tried and/or had any luck with a 'slow burn single use' solid rocket in a glider? It would have the advantage of high energy density, low drag and quick start.

https://www.youtube.com/watch?v=vsqg28y_s3s

As for whether or not it is practical, ask the high altitude model rocket guys how much the spend on a "shot" for one of their rockets with not near enough propellant to launch a glider. Then go take a couple of tows and see which you would rather do. But it is an interesting thought.

[John Galloway[_1_]]

IMHO it doesn't matter what kind of engine you have - at the
moment you reach for the start button of any motorised glider
you have to be 100% certain in your mind that it will not start
and have planned for that possibility. Then its nice when it does
start.

The actual probability of the engine not starting may vary
depending on the type and service status of the engine system
but the short term internal mental tool of 100% certainty of non-
starting should not.

(Even with the FES)

John Galloway

[Ian[_2_]]

On 04/16/2014 11:01 PM, wrote:

> Actually when you switch ON power switch, and get green LED, and
> "Controller ready" message on the screen, pilot can be 99% sure that
> motor will start. There is no engine which would be 100% reliable,
> but I think FES is close to that. Before each flight pilot needs to
> perform a short test run, in order to be sure that all is OK. If
> there is any problem in the system, is then showed already.

Have you ever considered building a pylon mounted electric sustainer,
and/or battery packs that are located in the wing? As elegant as the FES
is, the reliability of the electric solution would apply equally to a
pylon configuration electric sustainer. And if there is enough battery
power to operate the motor there must be more than enough to operate the
extraction mechanism.

Obviously it will not be quite a quick to start as FES, and there is a
possibility of a failure of the pylon mechanism which would prevent the
motor from starting, but this technology has been developed for petrol
sustainers/self launchers and should be reliable by now.

The advantage to a pylon installation is:

- No mods on the nose of the glider where tow release, pitot and/or air
vent are often mounted. This would save costs and may allow for an
easier certification process, ultimately making the technology available
on a wider selection of glider models.

- No aerodynamic drag penalty when the motor is retracted.

- Propeller protected from accidental damage on the ground.

- Many modern sailplanes are designed to accommodate a sustainer. These
should have the space and the strength to accommodate a pylon mounted
electric sustainer. Certification on these gliders should be easier.

Fitting batteries in the wing may become essential as the volume FES
currently uses to accommodate batteries would be occupied by the pylon
and motor. Batteries would need to be mounted in a container that can be
inserted/removed through the root rib. The challenges for this are:

- Batteries would have to be charged in place. This has safety
implications and may require more elaborate safety circuits. (I
understand FES recommend removing batteries for charging).

- Batteries would replace some or all of the water ballast capacity.
This would require modification to, or removal of, the water ballast system.

- Rigging would be heavier and rigging aids would be recommended.


The advantage of having the batteries in the wings is that it would
circumvent the "maximum weight of non-lifting components" limitation,
allowing installation in a wider selection of gliders. It may also
facilitate increased battery capacity thus increased range. The average
battery discharge on each use will be less which should result in
improved battery life.


But once you have got a pylon electric sustainer system sorted out, I
might even be able to fit one in my LS3a!


Ian

[Renny[_2_]]

On Thursday, April 17, 2014 2:09:58 PM UTC-6, Ian wrote:
> On 04/16/2014 11:01 PM, wrote:
>
>
>
> > Actually when you switch ON power switch, and get green LED, and
>
> > "Controller ready" message on the screen, pilot can be 99% sure that
>
> > motor will start. There is no engine which would be 100% reliable,
>
> > but I think FES is close to that. Before each flight pilot needs to
>
> > perform a short test run, in order to be sure that all is OK. If
>
> > there is any problem in the system, is then showed already.
>
>
>
> Have you ever considered building a pylon mounted electric sustainer,
>
> and/or battery packs that are located in the wing? As elegant as the FES
>
> is, the reliability of the electric solution would apply equally to a
>
> pylon configuration electric sustainer. And if there is enough battery
>
> power to operate the motor there must be more than enough to operate the
>
> extraction mechanism.
>
>
>
> Obviously it will not be quite a quick to start as FES, and there is a
>
> possibility of a failure of the pylon mechanism which would prevent the
>
> motor from starting, but this technology has been developed for petrol
>
> sustainers/self launchers and should be reliable by now.
>
>
>
> The advantage to a pylon installation is:
>
>
>
> - No mods on the nose of the glider where tow release, pitot and/or air
>
> vent are often mounted. This would save costs and may allow for an
>
> easier certification process, ultimately making the technology available
>
> on a wider selection of glider models.
>
>
>
> - No aerodynamic drag penalty when the motor is retracted.
>
>
>
> - Propeller protected from accidental damage on the ground.
>
>
>
> - Many modern sailplanes are designed to accommodate a sustainer. These
>
> should have the space and the strength to accommodate a pylon mounted
>
> electric sustainer. Certification on these gliders should be easier.
>
>
>
> Fitting batteries in the wing may become essential as the volume FES
>
> currently uses to accommodate batteries would be occupied by the pylon
>
> and motor. Batteries would need to be mounted in a container that can be
>
> inserted/removed through the root rib. The challenges for this are:
>
>
>
> - Batteries would have to be charged in place. This has safety
>
> implications and may require more elaborate safety circuits. (I
>
> understand FES recommend removing batteries for charging).
>
>
>
> - Batteries would replace some or all of the water ballast capacity.
>
> This would require modification to, or removal of, the water ballast system.
>
>
>
> - Rigging would be heavier and rigging aids would be recommended.
>
>
>
>
>
> The advantage of having the batteries in the wings is that it would
>
> circumvent the "maximum weight of non-lifting components" limitation,
>
> allowing installation in a wider selection of gliders. It may also
>
> facilitate increased battery capacity thus increased range. The average
>
> battery discharge on each use will be less which should result in
>
> improved battery life.
>
>
>
>
>
> But once you have got a pylon electric sustainer system sorted out, I
>
> might even be able to fit one in my LS3a!
>
>
>
>
>
> Ian

Ian,
Unless I am missing something here, are you really not talking about the system in the Antares 20E or something very similar?

If, as it seems from your message, you are talking about a retrofit, please be aware that there is a tremendous amount of complexity involved in an electric installation in a glider. Assuming you can work that all out, then you would have to deal with the bureaucracy of dealing with your local aviation authority such as the: FAA, EASA, etc, etc.
With tremendous effort and money, it may actually be doable, but it may be virtually impossible to be able to legally fly your electric glider. In addition, the costs of such as system may be far more than the value of one's "pure" glider....It really is a "vexing" problem!

Thx - Renny

[Martin Gregorie[_5_]]

On Thu, 17 Apr 2014 14:36:07 +0000, Wolf Aviator wrote:

> At 22:31 16 April 2014, son_of_flubber wrote:
>>I have a question about the history of soaring... (I'm not
> asking a
>>practic=
>>al serious question.)
>>
>>Has anyone tried and/or had any luck with a 'slow burn
> single use' solid
>>ro=
>>cket in a glider? It would have the advantage of high
> energy density, low
>>=
>>drag and quick start. I suppose that it might melt
> something important if
>>=
>>it were were mounted on the fuselage. What about a
> wing mount close to
>>the=
>> root?
>>
>>I know this idea sounds crazy, but a pop-up jet sustainer
> strikes me as
>>onl=
>>y slightly less outrageous.
>>
>>
>>
> Germans did Me-163. I know that it had not an 'slow burn' solid rocket,
> but it was liquid fuel, but still it was glider with rocket engine :)
>
.....but never something you could call a 'safe ride'.


> Regards Wolf http://youtu.be/WCej1kZInZk
>
Cool video, though.



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

[Edward Bittenbender]

At 22:31 16 April 2014, son_of_flubber wrote:

>Has anyone tried and/or had any luck with a 'slow burn single use'
solid rocket in a glider? It would have the advantage of high
energy density, low drag and quick start. I suppose that it might
melt something important if it were were mounted on the fuselage.
What about a wing mount close to the root? I know this idea
sounds crazy, but a pop-up jet sustainer strikes me as only slightly
less outrageous.>

Fritz von Opel in 1929.

www.youtube.com/watch?v=vsqg28y_s3s
Ed

[Edward Bittenbender]

At 20:41 17 April 2014, Edward Bittenbender wrote:

>www.youtube.com/watch?v=vsqg28y_s3

Sorry, the youtube link should have read:

www.youtube.com/watch?v=vsqg28y_s3s



Ed

[Ian[_2_]]

On 04/17/2014 10:30 PM, Renny wrote:

> Unless I am missing something here, are you really not talking about
> the system in the Antares 20E or something very similar?

The Antares is a purpose designed electric self launcher. It has a large
set of batteries to provide the necessary energy, accommodated in a
custom built open class airframe.

I am thinking of a retrofit, pylon mounted, electric sustainer. The mass
of the motor and batteries would be similar to the FES, (45kg) and
easily carried by many existing pure sailplane designs. The biggest
challenge would be to mount the batteries in the wings.

> If, as it seems from your message, you are talking about a retrofit,
> please be aware that there is a tremendous amount of complexity
> involved in an electric installation in a glider. Assuming you can
> work that all out, then you would have to deal with the bureaucracy
> of dealing with your local aviation authority such as the: FAA, EASA,
> etc, etc. With tremendous effort and money, it may actually be
> doable, but it may be virtually impossible to be able to legally fly
> your electric glider. In addition, the costs of such as system may be
> far more than the value of one's "pure" glider....It really is a
> "vexing" problem!

I am aware that this is a non-trivial challenge. I addressed my question
to Luka who has spent many years developing the FES system and getting
it certified. He is probably the best qualified person to comment on the
viability of this concept.

Ian

PS: My comments on modifying my LS3a were made with tong in cheek. Even
if Luka did bring a suitable kit to market it probably would probably be
better to start with a more modern airframe. At least I would have
something to fly in the meantime!

[son_of_flubber]

On Thursday, April 17, 2014 12:49:31 AM UTC-4, Mike the Strike wrote:

> Many of our emergency landing spots .... or smugglers landing spots near the border where you are likely to meet with armed villains).

As a Yankee and fan of "Breaking Bad", I'm having a hard time sorting fact from fancy. A run-in with Banditos (or the DEA suspecting nefarious cargo in the glider) is a possibility?

[Mike the Strike]

On Thursday, April 17, 2014 2:46:21 PM UTC-7, son_of_flubber wrote:
> On Thursday, April 17, 2014 12:49:31 AM UTC-4, Mike the Strike wrote:
>
>
>
> > Many of our emergency landing spots .... or smugglers landing spots near the border where you are likely to meet with armed villains).
>
>
>
> As a Yankee and fan of "Breaking Bad", I'm having a hard time sorting fact from fancy. A run-in with Banditos (or the DEA suspecting nefarious cargo in the glider) is a possibility?

One of our emergency strips not too far from the Mexican border is a semi-abandoned ranch strip that sees a lot of night-time use by smugglers. I landed there a few years ago and was retrieved by road uneventfully. A colleague who landed there more recently found two men had opened his canopy and were rifling through his cockpit after he'd walked away from his ship. They sped away on ATVs as he approached. Smugglers often have local ground support who use off-road vehicles and frequent deserted airstrips!

An FES system has some appeal!

Mike

[Greg Arnold]

Sounds similar to this project at DG:
http://www.dg-flugzeugbau.de/?id=1070


On 4/17/2014 1:09 PM, Ian wrote:
> On 04/16/2014 11:01 PM, wrote:
>
>> Actually when you switch ON power switch, and get green LED, and
>> "Controller ready" message on the screen, pilot can be 99% sure that
>> motor will start. There is no engine which would be 100% reliable,
>> but I think FES is close to that. Before each flight pilot needs to
>> perform a short test run, in order to be sure that all is OK. If
>> there is any problem in the system, is then showed already.
>
> Have you ever considered building a pylon mounted electric sustainer,
> and/or battery packs that are located in the wing? As elegant as the FES
> is, the reliability of the electric solution would apply equally to a
> pylon configuration electric sustainer. And if there is enough battery
> power to operate the motor there must be more than enough to operate the
> extraction mechanism.
>
> Obviously it will not be quite a quick to start as FES, and there is a
> possibility of a failure of the pylon mechanism which would prevent the
> motor from starting, but this technology has been developed for petrol
> sustainers/self launchers and should be reliable by now.
>
> The advantage to a pylon installation is:
>
> - No mods on the nose of the glider where tow release, pitot and/or air
> vent are often mounted. This would save costs and may allow for an
> easier certification process, ultimately making the technology available
> on a wider selection of glider models.
>
> - No aerodynamic drag penalty when the motor is retracted.
>
> - Propeller protected from accidental damage on the ground.
>
> - Many modern sailplanes are designed to accommodate a sustainer. These
> should have the space and the strength to accommodate a pylon mounted
> electric sustainer. Certification on these gliders should be easier.
>
> Fitting batteries in the wing may become essential as the volume FES
> currently uses to accommodate batteries would be occupied by the pylon
> and motor. Batteries would need to be mounted in a container that can be
> inserted/removed through the root rib. The challenges for this are:
>
> - Batteries would have to be charged in place. This has safety
> implications and may require more elaborate safety circuits. (I
> understand FES recommend removing batteries for charging).
>
> - Batteries would replace some or all of the water ballast capacity.
> This would require modification to, or removal of, the water ballast
> system.
>
> - Rigging would be heavier and rigging aids would be recommended.
>
>
> The advantage of having the batteries in the wings is that it would
> circumvent the "maximum weight of non-lifting components" limitation,
> allowing installation in a wider selection of gliders. It may also
> facilitate increased battery capacity thus increased range. The average
> battery discharge on each use will be less which should result in
> improved battery life.
>
>
> But once you have got a pylon electric sustainer system sorted out, I
> might even be able to fit one in my LS3a!
>
>
> Ian

[Ian[_2_]]

On 04/18/2014 03:15 AM, Greg Arnold wrote:

> Sounds similar to this project at DG:
> http://www.dg-flugzeugbau.de/?id=1070

That is a very interesting write up. However DG have chosen to mount the
batteries in the fuselage with the motor. Some interesting points from
DG's website:

"The sink rate with the extracted motor is much better than the
DG-1001T's sink rate due to the better aerodynamics and drag. So it was
possible to keep on climbing in weak thermals although the engine was
extracted."

It seems "plummet mode" with this electric pylon sustainer is not nearly
as bad as some of the anecdotes that Dave described in his presentation.

"We also found during the development process that the available space
and load allowance compared to the required battery is much better in
the DG-1001 than in the "LS10-ste" which had been the original plan.
This is why as a first step we have are developing the two-seater with
an electric motor, and the LS10 will follow once a new generation of
batteries is available."

FES have put the motor on the front. DG needed a two seater to fit the
motor into the fuselage with the batteries. If we are going to see a
main stream electric pylon sustainer in existing single seater designs,
it looks like the batteries will have to go in the wings.

I also note that DG needed partnerships and government subsidies to get
their electric sustainer off the ground. Clearly this is not a trivial
exercise.

According to

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

FES use 2 off 15kg batteries. Total voltage is max 118V. If you could
get one equivalent battery into each wing, that would be 59V DC per
wing. Enough for a very nasty shock, but not quite as lethal as the 200V
DC that DG talk about. With wing mounted batteries you could easily
afford to carry 20kg or 25kg in each wing. This would allow for either
heavier/safer battery technology, or more capacity. Bigger batteries
would have a lower discharge "C" rate and hence a longer life (ie more
charge/discharge cycles). Wing mounted batteries could be married to
DG's pylon, motor and electronics. (Or FES motor and control
electronics). Yup, I am just dreaming ...

Are there any DG-1001 electric sustainer owners on this forum? I would
love to hear some feedback!


Ian

[son_of_flubber]

Following on the single-use solid fuel rocket sustainer idea...

Does the math/physics/dollars work for single-use (non-rechargeable) battery pack for FES?

Scenario:Use once to avoid an expensive/dangerous landout, then replace the batteries.

With a single-use FES, you would retain the sporting attitude/fun of flying a pure glider. You would only press the start button to 'save your a--'. It seems uneconomical to buy an expensive set of rechargeable batteries unless you plan to use them often. If I had a rechargeable FES, I would end up flying it like a motor glider (not that there is anything wrong with that).

http://www.amazon.com/Duracell-Procell-Professional-Battery-Size/dp/B005TLKDZC/ref=sr_1_1?s=electronics&ie=UTF8&qid=1397852618&sr=1-1&keywords=d+size+batteries

Ten years from now you could upgrade to rechargeable batteries.

[son_of_flubber]

On Friday, April 18, 2014 4:44:42 PM UTC-4, son_of_flubber wrote:

> Does the math/physics/dollars work for single-use (non-rechargeable) battery pack for FES?

A quick look seems to indicate that the energy density of non-rechargeable alkaline batteries (the flashlight kind) is somewhat better than rechargeable LI batteries (the cellphone type), so a single-use-FES is not on-the-face-infeasible.

[Eric Greenwell[_4_]]

John Galloway wrote, On 4/17/2014 11:20 AM:
> IMHO it doesn't matter what kind of engine you have - at the
> moment you reach for the start button of any motorised glider
> you have to be 100% certain in your mind that it will not start
> and have planned for that possibility. Then its nice when it does
> start.
>
> The actual probability of the engine not starting may vary
> depending on the type and service status of the engine system
> but the short term internal mental tool of 100% certainty of non-
> starting should not.
>
> (Even with the FES)

Perhaps the plan could be the same one you have for the wing spar
breaking, or a control rod disconnecting.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

[Martin Gregorie[_5_]]

On Fri, 18 Apr 2014 13:54:13 -0700, son_of_flubber wrote:

> On Friday, April 18, 2014 4:44:42 PM UTC-4, son_of_flubber wrote:
>
>> Does the math/physics/dollars work for single-use (non-rechargeable)
>> battery pack for FES?
>
> A quick look seems to indicate that the energy density of
> non-rechargeable alkaline batteries (the flashlight kind) is somewhat
> better than rechargeable LI batteries (the cellphone type), so a
> single-use-FES is not on-the-face-infeasible.

Hint: there are AUVs working under the ice shelves in the Antarctic that
run off a pack of alkaline 6000 D-cells because these are the best
batteries to use atthose water temperatures.


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

[Muttley]

Just for those interested, there is also the Selfstarting Binder EB29D with a Watercooled electric Motor . (no connection to Mfg) for details see
http://tinyurl.com/pndtp69

[son_of_flubber]

So having FES increases the number of days that one might attempt XC?
And consequently one will turn the FES on more often than once every five years?

Do any FES owners care to confess how frequently they turn on the motor?

[Eric Greenwell[_4_]]

son_of_flubber wrote, On 4/19/2014 11:26 AM:
> So having FES increases the number of days that one might attempt XC?
> And consequently one will turn the FES on more often than once every five years?
>
> Do any FES owners care to confess how frequently they turn on the motor?

Confess? To what? Getting good value out of their purchase?

If a pilot isn't using the FES on 10% to 20% of the flights, the pilot
has wasted his money buying the FES. The FES can and should be used to
increase the amount and quality of soaring the pilot does, and flying so
conservatively it's rarely needed will not achieve that goal.

An FES (or any sustainer and self-launcher) sets you free to explore
soaring to it's fullest. What a sad thing if the pilot doesn't do so.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

[Chris Nicholas[_2_]]

Sof, it is a bit more complicated than that.

Just talking cross-country flights and only considering using FES to get home after having started (which is what I suspect you were getting at), I have only last year as a reasonable data set (illness andother things restricted my flying in 2011 and 2012 to few flights).

I did 17 cross-country flights in 2013and used the FES to get home on 3 or 4 of them. If 4, one was to be certain of crossing a big gap close to home and arriving with enough height to do a decent circuit/pattern, and avoid the risk of landing out in possible a bad field at the last moment.

But as well as those uses while completing flights, on 2 occasions I had winch launches, did not get a good thermal to climb away in time, and used the FES for a few minutes from about 700 feet to 1000 feet to avoid a relight - after which I climbed to a start height and returned to my start line (the home airfield) before doing an otherwise motorless flight. It is invaluable for such occasions too.

Then there were 5 other flights when it was barely soarable, certainly not good enough for cross country, but I used the motor locally - either just to keep in practice, or to do some flight tests to assess duration and climb rates (I have been doing some test flights as required by our airworthiness system and for feedback to Luka, the designer).

Dunno if this is what you wanted, but hope it helps.

Chris N