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Old Nov 04, 2001, 08:26 PM
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Joined Oct 2001
4 Posts
Herr Piper Cub Electric conversion help

This is my first electric, so have patience. I flew my Piper Cub for the first time today. Stats: 21 oz RTF, 48" span, 328 sq in area, 8.8 oz/sq ft load, I used the Geat Planes T-400 GD (1.7-1) with a 9X7 and later a 9X6 APC electric prop. I am using a GWS Naro reciever set up with the 2 amp speed control and a 7 cell 270 mah battery.
Performance is dissapointing as plane will not ROG and has a very poor rate of climb, it in fact will stall if rate of climb is not very conservative.
I am inexperienced with the electrics so my question is how to improve performance?
Seems to me that the mah and voltage of the battery might be the first place to start. Was going to try a 8 cell 600 mah pack was hoping that increased voltage/capacity would offset weight trade off.
Did I miss completely? Should this be a 600 setup? Or is there a more effiecient 400 GD than the Great Planes.
Not looking for a hot rod but would like more spirited performance, ROG at least.
Thanks
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Old Nov 04, 2001, 08:57 PM
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Rotten Robbie's Avatar
Kent, Wa.
Joined Feb 2001
642 Posts
I would change to a 5A ESC and an 8 cell pack. Get higher current battries also.
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Old Nov 04, 2001, 10:26 PM
D.G.B.
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Southington, Connecticut, United States
Joined Jun 2000
2,952 Posts
Johnbob,1) go to 8x800 ar batteries .2) i would also go to a bigger gear ratio.in my dallair sportster i use a 2.33to1 gear box .9x6 graupner slim prop.i know its not exactly the same plane but close.my esc is a jeti110.Also you will have to toe the wheels in./ \my plane is a hand full to r.o.g. but it will no problem.most of the time i just hand launch it, then do touch-n-go's with it.power is graupner sp400 .i had the same experiance as you.i read a artical review by bob aberly and i thought it was just what i needed to get into eletric flight.i also had the identical set up as him and the plane wouldn't fly. then i got some help from the ezone and never regret it yet!!!!! ITS JUST A ELECTRIFYING SPORT! stefanP

"Ghost rider requesting a fly by"
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Old Nov 04, 2001, 10:50 PM
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Mountain View, CA, USA
Joined Nov 2000
75 Posts
Upgrade your speed control immediately. There is no way a 2 amp controller will work for you. Buy something that will work for speed 400 motors geared or direct. The pixie 14 or pixie 20 are good bets, but if you go with another brand, get something that will at least take 10 amps. This is particularly important if you are ROGing off grass and end up with a nose over and engine stall.

Jim
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Old Nov 04, 2001, 10:54 PM
Almost a Pilot
Mauilvr's Avatar
NorCal
Joined Oct 2001
3,760 Posts
Your motor choice should be O.K. but I agree with the previous suggestions. You need larger capacity batteries - the 8X800 suggestion is a good one.
Your ESC is too small - your current draw is quite likely far >2 amps. Try to measure this with the larger batteries. You'll probably need a 5-10 amp ESC.
To get decent ROG you'll probably want to add a steerable tailwheel. Use the search function here on ezone and check out what has been done for the GWS Tiger Moth.
I think you're close - just a few changes necessary.
Good Luck!
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Last edited by Mauilvr; Nov 04, 2001 at 11:05 PM.
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Old Nov 04, 2001, 10:55 PM
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Mountain View, CA, USA
Joined Nov 2000
75 Posts
I was so stunned by the 2 amp speed control, that I failed to comment on the rest

You definitely need a better battey pack. Probably the only reason your speed control didn't already fry, is that your battery pack has so much resistance it can't produce the current your motor needs. As suggested above, a 7 or 8 cell 500-800 mah AR cell pack should work well. I'd go with 8, but it might be flyable on 7. As an alternate less costly solution, an 8 cell 600AE pack should work. After you get a better handle on the plane, you could try an 8 cell KR1400AE or move to Nimhs.

Jim
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Old Nov 05, 2001, 08:20 AM
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Joined Oct 2001
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I appreciate all of your comments. i am going to try the 8 cell 800 mah battery pack and also upgrade the esc. Is there a "neat" way to add a fuse?

Comment; this is my first try at electrics, I have been flying with glow for two years and love it. I have been really excited about trying the electrics and flying in the back yard, and I am sure that once the bugs are worked out the electrics should be a blast. I would like to let you all know that I really appreciate your help, as you can tell I am a real newbie to electrics but I am here to stay.

Thanks for all your comments, on another scale (ha ha) I have investigated converting my 1/6 scale Pica Waco bipe to electric, but the $400 tag is hard to get past.
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Old Nov 05, 2001, 12:21 PM
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Kent, Wa.
Joined Feb 2001
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<i><b>Is there a "neat" way to add a fuse?</i></b>

On the higher currrent ESCs tha have current limiting and thermal protection, is there really need for a fuse?

If so use a fuse at least double the ESC rating. It is not to protect the ESC. It is to prevent the plane from going up in flames. The fuse won't blow unless the ESC fails.

Robbie
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