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Oct 21, 2001, 10:18 PM
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Joe Elston's Avatar

Help!! Can someone please tell me how to hook up a twin in paralell?


I am building my first speed 400 twin and I need to know how to hook up the motors in paralell. Can anyone explain this to me? I would really appreciate it as I am a newbie in twins.
Thanks Joe
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Oct 22, 2001, 12:08 AM
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Brad Trent's Avatar
Joe:
You need to "Y" both the pos. and neg. output leads from the esc . Each motor will have a + and - lead to it from the controller, which must have a high enough amp rating to handle the sum of the 2 motors' amp draw. My 48" S400 twin draws 7A/side, for a total of 14A, and my Astro 217D handles this easily, since it's rated for 30A continuous. You'll find that twins seem to perform a little better than 2X a single motors output might suggest, and have a nice "cool factor" as well.
Brad.
Oct 22, 2001, 01:02 AM
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Joe Elston's Avatar

speed 400 twin


Thanks Brad, I think I understand now. Each motor gets hooked to the ESC that has two Y's of wire running from it. So the ,otors see all the voltage. I also have a 217D new in package that I will use for this plane.
Thanks Again Joe
Oct 22, 2001, 02:56 AM
high-speed freak
opualuan's Avatar
question... I've never built a twin, but since it's a twin speed 400, wouldn't it be better to get a left-hand and right-hand prop and hook one of the 400's contacts up backwards? seems like it would help to keep the plane from getting squirrely when you punch the throttle...
Oct 22, 2001, 07:19 AM
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Bill Glover's Avatar
If you can find matching props then counter-rotating motors is a perfectly good idea. But in reality the torque reaction from a pair of 400s is not severe, and pusher props are only made in a few sizes (so you'd be lucky to find the one you want).
Oct 22, 2001, 12:49 PM
high-speed freak
opualuan's Avatar
ok... I don't think this is necessarily about a twinjet, just a twin... could be any plane with twin speed 400's, so it might be tractor props...

I agree with you about supply of props... I'm still looking unsuccessfully for a pusher prop for one of my scratchbuilts (4.5x3 was optimal I think), with NO luck.
Oct 22, 2001, 06:37 PM
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Bill Glover's Avatar
Sorry, I obviously didn't explain that very well! If you want the motors going in opposite directions so the torque cancels out then one needs to be fitted with a tractor prop and the other a pusher prop (regardless of whether the plane has the motors in pusher or tractor configuration). Both props need to be the same diameter and pitch, but made for opposite rotation

An electric pusher doesn't normally need a pusher prop - you just run the motor in reverse (re-timing if necessary) and use a normal prop.