I have come across an old GP Electra Glider kit. As you know it is pre-
li-poly model and uses an old electric motor with a seven cell ni-cad.
Can someone give me advice on what to replace the motor and battery
with, plus anything else?
I have one of these which I flew with a Master Airscrew 05 motor/gearbox
turning a 12X8 folding prop. No speed controller, just an old Hitec On/Off
remote switch. Full throttle or no throttle.
recently flew it with a pair of 2S2500 mAh LiPo packs in parallel. Thought
briefly of switching to brushless then figured, whets the point? Motor is
only to get altitude for thermal searching and the can motor works fine.
After all, it IS a glider.
I will switch out the old on/off thingie for a proper LiPo capable speed
controller but that it.
Motor runs great at 7.4 volts and with the equivalent of 5 amps current.
Side note: Goldberg makes the Electra, not Great Planes. I have had two; the
first had a power disconnection on board which locked the servos into
perfect trim to circle the field ON GLIDE going higher and higher and higher
till it sailed over the hills and far away never to be seen again. Got to
watch it fly away for a good half hour. Would have given my left nut for a
rifle at that point...
You could weigh the current power system and put together something
around a brushless that weighs the same. If you bias the system toward
the smallest battery and biggest motor it'll go like a rocket; if you
bias it toward a bigger battery it'll fly longer on a charge.
Alternately, if you like how it flies you could go with a brushless motor
with about 70-80% the rated power as your current motor -- motors are
generally rated by their _input_ power, and brushless motors are
generally more efficient than can motors, so this would give you
_approximately_ the same power at the prop shaft. Then get the smallest
LiPo that works (or ditto NiMH, if you can even get those any more).
But if you do, you may find yourself putting a ton of ballast in the nose
to get it all to balance -- making up the weight with motor would be much