Gord:
I just had a minute to check out the Mosa rudder. with the tail wheel on the ground, no problem, but as soon as I propped up the tail, the thing started to chatter and drift. It still gave full force both directions, but it crept away off center. I trimmed it back, wouldn't go all the way and kept on chattering.
So I unplugged the servo lead and plugged a new servo into the receiver, and it worked fine. So it looks like a servo swap, not a receiver or transmitter problem. (I guess)
Ever see this before?
Reg