🚀 go-pugleaf

In article <JMOONAN.93Jan26094904@ccv1.bbn.com>, jmoonan@ccv1.bbn.com (John Moonan) writes:
> 
> 	I'm a long time wet power flyer but this past summer I decided to build
> an electric powered glider for a change of pace.  Ended up building a
> Goldberg Electra.  Power is the stock motor with a Master Airscrew 2.5X1
> gearbox and 12X8 folding prop.  Battery packs are 6 cell 1400 SCR, 7 cell 1400
> SCR and 7 cell 1700 SCE.  It flys great and I've had a lot of fun with it for
> the last 6 months.  Has a good climb on the 6 cell pack and very good climb on
> the 7 cell packs.  Now the question:
> 
> 	The motor seems to be drawing about 25-30 amps on a fresh charge. I say
> this because it blew 20 amp fuses after about 30 seconds of run but has not
> blown a 30 amp fuse yet.  Is this a reasonable current for this motor?  Would
> I be better off going to a 3.0X1 gearbox or a different prop?  Am still using
> the original motor (has about 40 flights on it) and wondering how much longer I
> can expect it to last.  Any suggestions for replacement motor (other then
> AstroFlight which are expensive) when the time comes?  Would some of the
> modified motors that the car racers use work?  How many turns, etc.??

I'd guess that the motor is drawing on the low side of 25 amps, which is
still a lot for a standard 550 and would explain the good climb :-)
An Astro 05 draws around 25 amps in flight, the FAI version nearer 30
(depending on prop size). The main difference is that the Astro's are
more efficent at these high currents, and will last a lot longer!

As for a replacement motor, the standard 550's are cheap so you could
stick with them. Another option may be the Goldfire 550 motor - I'm
not sure if this is a standard 550 or an improved one but it's sold
as an electric flight motor.

A problem with car motors is that they are generally set up to run too
fast for aircraft use. However a guy in my club gets good performance
from a Kyosho "truck" motor, which is designed for torque at low speeds
(compared to most car motors).

Chris Kaiser

Postgrad, Elec. Eng. Dept.
University of Canterbury
Christchurch, NEW ZEALAND