Ventus 2cxa with FES

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 a

- 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

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 a



- 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

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!

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 a

- 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

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

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-Proce...size+batteries

Ten years from now you could upgrade to rechargeable batteries.

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.

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 |

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

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?