Servos shake on full throttle
 

Hey

I have an Uproar 40 with a .46FX engine and I have a problem with the servos/engine...
Whenever I turn to full throttle the servos start to move a little and all the surfaces with it. It doesnt happen with the engine at a lower speed.

What could cause this? the vibration from the engine..?

Thanks

RE: Servos shake on full throttle
 

Sounds like something is generating radio interference. Is the throttle pushrod metal? Possibly with a metal clevis on the engine? Look for anything on or around the engine that could cause metal to metal vibration.

RE: Servos shake on full throttle
 

Vibration caused by; loose engine mount, loose engine to mount connection metal pushrods vibrating, loose muffler, ect. ect.
Try tapping on all the various parts of the plane with the plastic handle of a screw driver, and see if anything makes a "loose" sound (rattling instead if solid). Check all nuts, bolts, screws, ect. Make sure your Rx is isolated well, and double check to be sure the crystal is fully plugged into thr Rx.

Jetts

RE: Servos shake on full throttle
 

I have seen this caused by poorly built servo extensions. I would try to replace those first or at least move them around to see if the problems moves.

RE: Servos shake on full throttle
 

The only extensions that I use in this plane are for the ailerons but all the other surfaces shake as-well so I dont think thats the problem.
Ill try to check for anything loose on there.

Thanks

RE: Servos shake on full throttle
 

is your antenna looped around near itself? if it is, that could be your problem. also, true. metal throttle pushrods are notorious for causing interferance. especially if you have metal clevises on them. how far is your rx from your engine?

RE: Servos shake on full throttle
 

Do a range check at around 30 paces away with the xmtr antenna collapsed and the engine running. If it freaks out before you get to 30 paces, check your receiver antenna's routing and make sure it is free of obstructions. How is your receiver antenna routed on the plane?

Jesse

RE: Servos shake on full throttle
 

I would do a good range check, engine running, to see if you have a radio interference problem. If there is no noticable glitching in the servos go to full power and check again, if it only is noticable at full throttle I would take the prop off and balance it to see if that could be your problem. I know there are a lot of people out there that dont belive it is necesary to balance a prop but I have seen first hand what a prop that is badly out of balance can do the end result was a H-9 cap 232 sport that was shaken to pieces.