I too have had the 8411 rudder dance and the cure for me has been to fit the complete plastic gear set that has the JR part no. "JRC 8231GS for 811, 8201, 8301, 8300"

Initially I tried just fitting the intermediate plastic gears, leaving the metal output gear. Effectively this gives you an 8411SA This worked OK for a few flights and then the wiggle was back. Changing the output gear for the plastic one cured the wiggle completely. I am pretty sure that in this spec. what we have is designated 8401 here in UK. Basically, the 8411 servo is underdamped and the slight backlash in the metal gears is enough to excite it.

On another topic can anyone tell me what clevises fit the holes in the fibre horns of the Impact? I am used to the ball race MK system with no slop but as Composite say not to use a single sided attachment t their horns I have been trying to find a suitable clevis. All the ones I have tried have a little slop in the Impact horns, the best being an unbranded 3mm metal clevis.

Malcolm Harris