Unfortunately there is a "maximum weight of non lifting parts".
You may need to put the batteries in the wings. See The Binder EB29DE
at http://www.binder-flugmotorenbau.de/eb2900.html?&L=1
Not a show stopper but extra complication.
To raise a 500Kg glider through 2000 meters(launch plus retrieve)
requires 10 megajoules of energy plus what energy was required to
keep it in level flight for the time taken to get there. Say 1/3 of
that. More powerful motors are better but prop efficiency suffers as
you put more through the same diameter prop. Interesting tradeoff and
design iteration.
1 kilowatt hour = 3.6 megajoules.
Prop efficiency and motor efficiency losses will be at least 50% so
you need around 7.5 kilowatt hours of energy in the battery. You
won't want to discharge it deeply if you can help it so a little
extra helps. Say 8 kilowatt hours.
Currently the LiFePO4 batteries (currently safest Li technology) can
get around 100 watt hours per kilogram so 80 Kg of batteries. Maybe
100 Kg installed with portable charger, motor, prop and controller.
It will end up similar to flying a motorless glider with water ballast.
Not impossible. That retrieve should get you to an airfield of some
sort at least but probably not home if you like the longer cross
country flights.
Li - ion batteries may do a little better but need more protection
circuitry/physical barriers etc all of which add to weight.
Mike
At 08:09 AM 22/06/2014, you wrote:
http://www.zeromotorcycles.com/au/
54 horsepower for 20 Grand, FES and electric refits for old
sustainers and self launchers are getting closer by the day. By the
look of it you can add power packs easily. There is a video in there
some where about supermoto racing, for those of you not into
motorcycles the standard engine is very similar to a self launcher
albeit in 4 stroke mode.
I know it's simplistic but
Keep mast, prop and prop flange.
Remove engine and fuel tanks.
Epoxy in battery holders and bobs your uncle.
Justin
Justin Sinclair
17 Queen st.
Scarborough Qld 4020
Hm 07 3885 8949
Mob 0421 061 811
Email [email protected]
Sent from my iPad
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