RCMF

Level 1 => Electric Flight Technical => Topic started by: Buttered Cat on January 03, 2020, 21:57:36 pm

Title: Servo Over Rotation
Post by: Buttered Cat on January 03, 2020, 21:57:36 pm
I have an old Minium Piper Cub that I want to resurrect but I have a problem with two of the servos. They are over rotating.
The elevator servo just spins continuously, so the elevator itself continues to move up and down, full deflection.
And the aileron servo turns as far as it can go, and then gets stuck.

Does anybody have any idea why this might happen? And more importantly is there a solution?

IMG_2013.JPG
Elevator.png
Aileron.png
Title: Re: Servo Over Rotation
Post by: pooh on January 05, 2020, 14:52:23 pm
I assume the servos are as old as the plane?

As the servos are obviouslyfaulty, they are a bin-job. If it were me, I'd replace all the servos.

As to why it is happening, as a first guess I'd say the feedback potentiometer is open-circuit so the control circuit has no idea where the servo arm is pointing and just applies full rotation in one direction.