I have used solid pull-pull on IMAC panes and have had it happen when one servo only was attached. When two servos were attached they seemed to dampen out each other.

I had all of my 8411's "softened" a long time ago. If you put a rubber band on across, (and pinching), the pull-pull wires it stops doing it. It seems to depend a lot upon the mass of the control surface and, in my case, it is most prevalent when ball bearing connectors are used. Any friction in the system, such as a regular pin clevice and horn, seems stop it happening with a known "bad" servo.

I am not talking about a "buzz" or small bad-pot flutter here. I am talking about a pretty destructive self-perpetuating oscillation. The rudder was moving very quickly and in excess of two inches in both directions.

Why I asked about the JR servo is that the instructions actually, and I have remarked, unsually so, call for the 8411 and a very strong servo arm. Furthermore the issue is still, "why are these fusealges experiencing damage?". I would hate to have done all of my "preventative-construction" only to find that the servo "weakness" was the real culprit.

Regards,

Eric.

BTW - I tried two different 8411's and two car steering "Z whatever" equivalents and they all did it to some degree or another. All were new or serviced recently. I then put in an 8611. Bingo! no more issues, no matter how much I bounced the sticks!