Which sustainer system would you chose for your sailplane?

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

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

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

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

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

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

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

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

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

Ian

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

Benefits? Who cares!

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

Chris



At 20:33 25 September 2012, wrote:
Dne torek, 25. september 2012 18:00:15 UTC+2 je oseba Eric Greenwell
napisala:
On 9/25/2012 7:21 AM, Tim Mara wrote:

For performance, low weight, LOW drag, simplicity and safety. JET!

More manufacturers are developing or exploring Jet sustainers. Quite
simply

the lack of moving parts, the very low weight to power output and
when

properly configured to have the computer take the pilot out of
decision

making of the actual operation of the engine the reliability of
operation

make the Jet the best possible solution. The HpH 304 Jet doesn't
require

massive, heavy and possibly hazardous batteries, doesn't require
start-up

and operation or typical reciprocating engines, no priming, no
chocking,

decompressing or diving to windmill and engine to start, no high
parasitic

drag (the jet engine expended has actually less drag than the landing
gear

down), no wind milling propellers, and short time from switch on the
switch

off and stored, literally seconds to start so even at low altitudes
can
be

operational in seconds and without the high drag of a propeller is a
non

issue when it might be necessary to glide the extra distance to make
a
safe

landing with an extended powerplant.

The Jet does have to be engineered right from the start and have
systems

that are completely monitored and controlled by a computer system to
take

the operator error possibility away and this is what has likely
delayed
the

release of the Jet sustainers from most manufacturers. Having flown
just

about al types from simple 2 cycle ultra-lites to small corporate Jet

aircraft I can see potential issues with operators not fully trained
in
Jet

engine operation without the development of a computer based system
to

control the operation of the jet engine. With the HpH system the
controller

monitors all aspects of the engine from start-up to engine cool down
and

stowage, it is simply refined ...

regards



Tim makes some excellent points for the jet sustainer, but every one of


them also applies to the FES. Sure, it's got those "possibly hazardous

batteries", but it does not have those "possibly hazardous 8 gallons of


fuel".



This illustrates the problem with the current voting choices, offered

without any description of each systems attributes. Even a dealer does

not tell us the important differences between two of the three choices,


so how can the average "voter" make an informed choice?



--

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

email me)


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

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

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

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

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

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

Regards,

Luka

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

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


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

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

Dne �etrtek, 27. september 2012 02:07:47 UTC+2 je oseba waremark napisala:
On Thursday, September 27, 2012 12:00:04 AM UTC+1, Chris Davison wrote:



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





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



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


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

http://www.youtube.com/watch?v=pTeNK...layer_embedded

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

Here are my answers:

Dne petek, 28. september 2012 23:50:12 UTC+2 je oseba RW napisala:
Luka,

Many of US glider ports have 4-5000ft paved runway.

Do you think electric scooter hub motor would help FES launch

850lbs Standard glider?

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

http://www.youtube.com/watch?v=3gLH9...layer_embedded

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

Do you think , you could change shape of the batteries so we can slip

them in the wings instead of water bags ?

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

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

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

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

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

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


Ryszard