Problem speed controller
 

I bought one of those made in China nameless speed controllers, a 50A for my 540, 6 to 7 cell electric glider and when all was switched on, as I moved the throttle lever on my radio, the speed did increase, but my rudder and elevator were intefered and flutterred. As I put the throttle to the max, the rudder and elevator also went to the max movement guaranteeing an early death to my favorite 2mtr glider. There is one large noise capacitor already installed on the motor one only across the +ve and -ve posts. There are none from +ve to case and none from -ve to case. I hear these are also required??? I was told to cut the red wire and add a seperate nicad pack to power the servos and this worked but added too much weight to the glider. Is the speed controller defective or its the noise capacitor thats not sufficient? My RX is about 4inches from the motor, the cabin is too small to push it further away. Any help from you guys will be greatly appreciated, thanks.

RE: Problem speed controller
 

It sounds a little different but my Dad had a shockflyer that would have all of the surfaces got to full deflection when he gave it full throttle... We fixed the problem with an FMA servo buffer between the speed controller and the receiver. Hope this helps.

RE: Problem speed controller
 

Was your dad's motor a brushed or brushless?

Bill

RE: Problem speed controller
 

brushless

RE: Problem speed controller
 

That's definitely interference, possibly caused by the speed control, or at least the proximity of the ESC to the receiver. Unfortunately, there's no scientific way to find that "smoking gun," to definitively say that such-and-such is the problem, then fix it. It's a trial-and-error process.

You've pretty much elminated the main possible remedies as courses of action, so you've got two left:
1. Add the capacitors, see if that helps.
2. Replace the ESC with another, less questionable brand of ESC.

You could try to disable the BEC, just to see if it works. Carefully pick the center (red) pin out of the servo connector with the tip of an Xacto and tape it back. This way you can try a separate receiver battery, then re-insert the pin later to re-enable the BEC.