AstroFlight 05FAI/gearbox is still a good combo

[Ex14th]

Gord was having performance problem with his FAI05 geared but also concerned that putting a bigger prop (he was using a 9x5) on it might draw an already high current of over 35 amp, but the plane wasn't going anywhere. We fooled around with an 11x6 Master Airscrew, and guess what, the current increase was minimal - the watt meter was indicating a draw of about 36 amp, but with a very impressive rpm of 7.8k, on a half depleted 7-cell. Nice comination. Don't throw those brushed Cobalts away yet.



Edited by - Ex14th on 29 Aug 2004  11:58:06 AM

[piker]

Wow!  A current increase of 36A!!  That's 100%  

Actually, I'm surprised that the current only went up one A with such a prop change.  Interesting.

I know the FAI's need to be run hard to be running in their efficiency range.

Robert

[Tomahawk]

I was also surprised at only a 1 amp difference with such a dramatic prop change.  I somewhere have the specs for this motor but I can't seem to find them at this time, but I will post them for you when I find them.

Chris

Flying quietly in Southern Ontario.

[Tomahawk]

I see Astro doesn't produce the FAI series of motors anymore.  I still can't find the info in this mess on my desk but I did find some old info on the net.  The FAI motors were to be used for short duration and pushed hard in sailplane use.  The info for the FAI 05 geared I found is 7 cells, 12*8prop, 320watts @ 50amps @ 7300rpm producing 2.9lbs of thrust.  Like I said earlier this was at a short duration as I assume the motor gets kind of hot and we wouldn't want to demag the magnets.

Chris

[Ex14th]

Gord, Listen to Chris' advice, and you will have a happy motor. May be put it in your favourite glider, and use it for LMR - limited motor run, get it up where you want in 4 seconds?

[gordonbw]

Food for thought... I am restoring a really nice 2.2 meter Robbe e-glider that I purchased from Alex recently.  Based on Chris's feedback, it seems the Astro FAI05 will a much better match for this plane than the sport model it's in now.

Or, I suppose I could get a higher ratio gearbox and run the 05 below its optimum efficiency level?



Edited by - gordonbw on 31 Aug 2004  8:38:25 PM

[Ex14th]

Get a planetary gearbox for it, and it might even come as high as 4.5:1 gear ratio, and swing a 14 x 7 folder, and you will be up there in no time. Just a thought

[Tomahawk]

Since Astro doesn't have any info on their site.  I was wondering how many turns this motor is.  Usually there is a number located on the side of the endbell.

Chris

Flying Quietly in Southern Ontario.

[bfeist]

I believe the sport is 7 turn and the FAI is 5 turn.

I have a CEM chinese cobalt 05 6 turn that I remember being in the middle.

Benjamin Feist - EMFSO Site Developer

[gordonbw]

It is, in fact, a 5 turn motor.

Gordon Braun-Woodbury
“Crashing builds character. Really!”

[Tomahawk]

While googling around I found a link to Sheldon Hobbies and they list a Astro FAI 5 turn and a seperate Astro FAI 6 turn motor.  The info I found that I posted earlier didn't specify which FAI 05G motor it was. (Just to let you know.)
It is too bad that Astro doesn't keep up an archive of info about their discontinued motors so people can look up recommended battery and prop combinations.  Their motors do last a long time.

Chris

Flying quietly in Southern Ontario.

PS Maybe you can fire a e-mail off to Astro and see what they recommend.




Edited by - tomahawk on 02 Sep 2004  04:07:26 AM

[Ex14th]

And then Bill Merko bought a brand new Astro Flight 40 8-turn direct drive with prop. adapter and a MA 10x6. We took a look at the commutator at our club house after the morning session of flying this morning, and it was spanking shinny and obviously never been ran, what a find. He will be using in his CG Eagle 2, that would fly it with authority.