Front Electric Sustainer

On Apr 16, 8:19*pm, Darryl Ramm wrote:
On Apr 16, 4:35*pm, "noel.wade" wrote:
On Apr 16, 3:55*pm, Greg Arnold wrote:

I see that the webpage now has pictures of the latest design, with a
bigger prop, and a more streamlined attachment to the spinner. *Also a
video of it running at Aero.

After the flight tests this summer, it will be interesting to get
information about its real world climb rate and range.

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

Very tempting! *Only downside is the incompatibility with all of those
nose-hook-equipped gliders out there. :-P

--Noel
(who's DG-300 has a CG hook - yay! *But unfortunately also a pitot
system in the nose - boo...)

Their answer for pitot is easy, you move it to use the tail. Any
certification issues introduced will need to be handled. Do you know
for sure that this requires replacing all "forward" tow hooks. In the
case of the DG-300 forward tow hook us really under your knees. *For
real nose tow hooks it may be an issue, including those gliders with a
CG hook but the flight manual does not allow aerotowing with the CG
hook, yes I know like that will stop everybody.

And for a DG-300 it is very irrelevant since the full solarium canopy
is going to prevent the install of a FES anyhow. I wonder how many
gliders really have room to do this install. I'm around 5'9" and I
can't see how there will be space in the nose cone area of most
Schleicher gliders, even if you could get rid of the canopy lift
mechanism (convert to a side hinge). So does that leave the market
with side hinged gliders with large nose cones and/or very short
pilots where the gliders, and then there is the catch that more
recently made gliders are going to have the EASA prohibition on
aerotowing with the cg hook?

While some of the text on their web site sounds like they are talking
about retrofit kits I wonder if this is really a viable business,
given it's going to have certification issues in many markets. And
there is likely a lot of work doing modification kits and
certification etc for each model (and I know Bob they all start with a
Sawzall). I wonder how much you need to select for the higher value
gliders who's owners are willing to spend $$$ on their toys. It will
be interesting to see how/if this gets to market. Still an interesting
idea.

Darryl

I had the opportunity to see it in Friedrichshafen, and it looks
nice. Prop is shaped to hit fuselage before canopy, might
require tailoring for each glider.

Real-world measurements of drag increase when stowed,
as well as climb and cruise performance, will be interesting.

Issues for retrofit include:
- certification (experimental only more likely, not in EASA)
- structural support and access for batteries
- relocation of pitot, hitch
- installation of power cables
- possible rework of supports for canopy, rudder pedals in nose

Installation of the motor may be the easiest bit !

If anyone is interested I'll try post some pictures
next week.

See ya, Dave "YO electric"

Greg Arnold wrote:
I see that the webpage now has pictures of the latest design, with a
bigger prop, and a more streamlined attachment to the spinner. Also a
video of it running at Aero.

After the flight tests this summer, it will be interesting to get
information about its real world climb rate and range.

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

Why not go self launch, discarding the batteries and using a detachable
1000 m to 1500 m long aluminum extension cord to the glider, which would be
connected to batteries or an electric generator on the ground. Launch would
require circling up to release altitude (not much different than
thermalling.) But since this is just an off-the-cuff idea, I can see some
issues with side loads of the extension cord during circling, even if the
cord is attached at or near C.G.

And for sustainer or temporary boost, I suppose one could still include
some on-board battery power.

Jim Logajan wrote:
/snip/
Why not go self launch, discarding the batteries and using a detachable
1000 m to 1500 m long aluminum extension cord to the glider /snip/

...or perhaps even more practically, provide a takeoff battery which
is ditched to a parachute descent at altitude?

:-)

Brian W

brian whatcott wrote:
Jim Logajan wrote:
/snip/
Why not go self launch, discarding the batteries and using a
detachable 1000 m to 1500 m long aluminum extension cord to the
glider /snip/

...or perhaps even more practically, provide a takeoff battery which
is ditched to a parachute descent at altitude?

:-)

Brian W
The last half doz or so posts have very good. :-)
...Lew...

Jim Logajan wrote:
Greg wrote:

I see that the webpage now has pictures of the latest design, with a
bigger prop, and a more streamlined attachment to the spinner. Also a
video of it running at Aero.

After the flight tests this summer, it will be interesting to get
information about its real world climb rate and range.

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

Why not go self launch, discarding the batteries and using a detachable
1000 m to 1500 m long aluminum extension cord to the glider, which would be
connected to batteries or an electric generator on the ground.

Self-launch would require a much bigger motor and propeller. The bigger
motor would require considerable modification to the fuselage portion
ahead of the wings to take the thrust, weight, cooling, and size of the
motor. The bigger propeller would require a much taller landing gear,
requiring a complete redesign of the midsection and the gear. This much
modification eliminates the advantage of the original concept, which is
easy adaption to a glider already in production.

There is a potential exception to this problem: the Carat already has a
front mounted motor and tall gear. It would still require substantial
modification of the nose to optimize it for a front mounted electric
motor, but not nearly as much work as the typical mono-wheel glider. I
do not think the Carat has enough wing area to carry the batteries
needed for self-launch, so maybe it needs the 18 m Discus wing instead
(or that long extension cord). Oops, more modification! It would be an
intriguing glider, though.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

I do not think the Carat has enough wing area to carry the batteries
needed for self-launch, so maybe it needs the 18 m Discus wing instead
(or that long extension cord). Oops, more modification! It would be an
intriguing glider, though.


hmm... a new direction for the Glidair project to take?
http://www.hpaircraft.com/glidair/ Brad, ya lisnin?

-paul

Eric Greenwell wrote:
Jim Logajan wrote:
Why not go self launch, discarding the batteries and using a
detachable 1000 m to 1500 m long aluminum extension cord to the
glider, which would be connected to batteries or an electric
generator on the ground.

Self-launch would require a much bigger motor and propeller.

I should have started a thread on electrically powered launch, rather than
post a followup to this thread. I was thinking de novo design of a glider
that would be using extension cord for power delivery, not specifically for
the referenced sustainer system.

That is, if one starts looking at electric motors for self-launch power,
and one is starting from a clean sheet, all options for energy storage and
getting power to the motor should be looked at. Not just batteries, which
are IMHO horrible sources of energy storage.

Speaking of props, another unusual idea to consider is actually using a
smaller prop. To get the same thrust requires more power and higher pitch,
but if power is considered "cheap" enough during launch, then a smaller
prop would not be an issue.

Also with respect to motor size: the peak versus continuous limits for
electric motors is, I believe, mostly dependent on cooling rate. Make the
motor "perspire" a bit and one might get away with a much smaller motor
than otherwise. So add some water as a heat sink (boils off) and one may
come out ahead for the kind short duration usage one sees in a glider
launch.

Some outside-the-box ideas for power delivery probably are best reserved
for implementation on April 1: microwave transmission from the ground or
via high-powered lasers. Though heated meals would be available early in
flight, so maybe worth considering. ;-)

On Sun, 18 Apr 2010 18:21:13 -0500, Jim Logajan wrote:

Speaking of props, another unusual idea to consider is actually using a
smaller prop. To get the same thrust requires more power and higher
pitch, but if power is considered "cheap" enough during launch, then a
smaller prop would not be an issue.

Smaller with more blades and the same pitch would be better. Raise the
pitch and more of the blade is stalled for the first part of the take-
off. Take it to extremes and the blade will be partially stalled during
climb-out - provided the glider accelerates fast enough for you to get
over the fence.

That's the advantage of the Antares - swinging a 2m prop at 1600 rpm gets
good acceleration and a great climb rate as well as much reduced noise.

Its not a really good comparison, but I've watched an Antares follow an
ASW-22BLE off the grid on a very calm day. The Antares was off the ground
in about 1/3 the distance and climbed out at least twice as fast.

I'd put a lot of that that down to the use of a big two blade prop
compared with a much smaller five blader with a bit of assistance from
the Antares' 42 kw motor vs 37 kw on the ASW-22BLE: much more of the ASW
prop disk in in fuselage turbulence plus the inter-blade interference is
getting fierce with that many of them beating the air to death.


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

Hi All,

I'm looking at ways to power my ASW22A. I've looked at combustion
windmills, electric windmills, jets and now FES. This led me to have
an email exchange with Mr. Znidarsic, director of LZ Design and
producer of the FES, about the possibility of putting his FES in my
ASW22. His answers are below:

"With 600kg TOW and best L/D 60, you would need about 10kg of thrust
for horizontal flight (in still air), which is around 5kW of power.
With 20kg of LiPo cells you could run the motor for around 40 minutes
in horizontal flight, depending on cell temperature and atmospheric
conditions. Max climb rate would be around 1.3 m/s for about 15
minutes, maximum altitude gain would be around 1000m. With more cells
(2 packs, 40kg), range, climb rate and maximum gained altitude would
be better of course. With time batteries are likely to improve, so we
can expect even better performance."
"The ASW22 might be an appropriate aircraft for the conversion as
there is enough space for the motor, batteries and the controller.
There must of course be enough margin for weight of non-lifting parts
(35-40kg for a standard installation).
Target price is like the additional price for sustainers with a
Solo2350 engine, which is around 17.000 € + VAT, all included. If you
would like to have more batteries than the price will increase with
abut 4000 € for an additional 20kg pack."
"To answer your question on putting the batteries in the wing roots:
in my glider the batteries are located in the fuselage behind the
wings so that they compensate the weight of the engine in the nose. It
is also the best position from a safety perspective as in case of a
crash there is a lot of glider structure between the pilot and the
batteries. Another positive point is that your luggage compartment is
still the same as before, and the batteries are easily accessible for
charging from the top of the fuselage (we usually leave the glider in
the trailer on the field). Putting batteries in wing roots would be
fine of course, provided that the required space is adequate and that
the additional weight in the wings is accounted for (rigging).
With reference to your remark about an extension version like the PSR
Jet system, this would be a much heavier solution, more complicated,
and not so efficient as the extended motor would have a lot of drag.
We could use belts, but then you loose efficiency and you would have
the same problems as current windmill solutions with combustion
engines. With the FES the glider is still very clean with the same LD
at powered flight, so for horizontal flight only mimimum power is
required!
PSR is nice too, but FES have better climb rate, faster start,
simpeler solution, lighter and much lower noise. And batteries will
improve in the future whereas the fuel consumption of jets will not
likely change."

Summing it up, I think it all depends on what one wants to get out of
the glider.
The FES is an elegant sustainer solution, however, it is definitely
not suitable for powered takeoff or landing.

Self-launch will not be possible; with a required more powerful system
for one there'd be too much risk to any prop in the nose, unless the
takeoff method is unsticking the main gear first or 2 engines are
installed in bubble pods protruding from the wings. With bungee or car
tow launch, after takeoff and climb to altitude hardly any power is
available for cruise or sustainer operations having you end end up
carrying those 60+ kgs and slightly lower L/D with you all day. FES
calls for a normal takeoff.
Another reason to have power available is for an out-landing (to have
power available for a missed approach), and similar thoughts apply
here as well; a heavier aircraft with no option to use the power
unless one is very skilled in keeping the nose clear of terrain.

I can have a jet sustainer solution with 1 or 2 engines which is
usable in landing as well, and partly or completely replace the
waterbags with fuel bags for extreme sawtooth range if so desired
(great plus in Europe). Plus, after the fuel is gone most of the
additional weight is gone as well, and the L/D is still at maximum
since nothing protrudes. There's the noise of course... but what fun!

I've visited the MRO where the jet conversions are done. It sure helps
with the decision to see the whole conversion process up close, on EU
type-certified aircraft.

On Apr 18, 7:51*pm, Martin Gregorie
wrote:
On Sun, 18 Apr 2010 18:21:13 -0500, Jim Logajan wrote:
Speaking of props, another unusual idea to consider is actually using a
smaller prop. To get the same thrust requires more power and higher
pitch, but if power is considered "cheap" enough during launch, then a
smaller prop would not be an issue.

Smaller with more blades and the same pitch would be better. Raise the
pitch and more of the blade is stalled for the first part of the take-
off. Take it to extremes and the blade will be partially stalled during
climb-out - provided the glider accelerates fast enough for you to get
over the fence.

That's the advantage of the Antares - swinging a 2m prop at 1600 rpm gets
good acceleration and a great climb rate as well as much reduced noise.

Its not a really good comparison, but I've watched an Antares follow *an
ASW-22BLE off the grid on a very calm day. The Antares was off the ground
in about 1/3 the distance and climbed out at least twice as fast.

For those who have watched these same types of gliders
take off in sequence in Uvalde, also note that I was flying
the Antares at a much higher wingloading, and still get
very rapid acceleration and good climb.

I'd put *a lot of that that down to the use of a big two blade prop
compared with a much smaller five blader with a bit of assistance from
the Antares' 42 kw motor vs 37 kw on the ASW-22BLE: much more of the ASW
prop disk in in fuselage turbulence plus the inter-blade interference is
getting fierce with that many of them beating the air to death.

Don't forget the big difference in drag of the pylon and cooling...

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

Best Regards, Dave "YO electric'