Great Planes Spectra

Motors, speed controllers, batteries and other e-power stuff

Great Planes Spectra

Postby hohocc » Tue Jan 01, 2013 6:45 am

I've got an old (but low mileage!) great planes spectra that I'm freshening up for a return to the sky. Can't help but thinking that since it was built in the mid 90s that things have moved on a bit and I could do with some advice/education.
It's powered by a great planes goldfire RS550SH, according to a brief look on the interweb this is a bit of a dinosaur. A servo turns the power supply on and off to it. The prop is a folding 8x4.5 which I'd like to keep if possible so externally it looks like it always has.
The battery is a huge nicad 1400mah 8.4v weighing an awful lot!
On the tower hobbies site they show the current motor specified is this one: ... LXJ766&P=V
ie a great planes electrifly s600 7.2-8.4v ferrite motor, current 26-28a, power 165w, thrust 19-21oz and will turn an 8x4 prop at 11820 to 12300rpm on 8.4v.
The trouble with tower hobbies is of course the freight cost, I've looked on hobbyking to try to find an equivalent motor (which must be there somewhere) but am lost. Of course I also need to decide on a battery (life preferably), and I understand I'll need an ESC to add to my confusion.
So at this stage I can't get my head around the numbers and the terminology surrounding electric flight, I've taken a look at a couple of online calculators and not got very far with them so if anyone can provide advice as to where to look for info, or their take on which motor/battery/esc from hobbyking I could use I would be grateful!
And another question, as it is set up the motor is either on or off, with an esc does the power output become variable? And does the esc need a servo to control it, or is it controlled directly from the rx?
Also, currently there is the motor nicad and an rx nicad, can the whole shebang be powered by one life/lipo through the esc?
Posts: 36
Joined: Tue Oct 09, 2012 8:39 am

Re: Great Planes Spectra

Postby hohocc » Tue Jan 01, 2013 9:16 pm

Oops looks like I hit enter twice...
Please see the above thread!
Posts: 36
Joined: Tue Oct 09, 2012 8:39 am

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