Model 2 adverse yaw?

[dholly]

I believe the I-III flapperon mixer is virtually a direct copy of the Avid Flyer units. There is a modified part offered by Airdale that adds an amount of 'differential' to the aileron control. The part is something like F-7a or similar. Brett would know off the top of his head. This may help your situation.

Looking at my KF-III mixer, I do not believe these parts are directly interchangeable. The Avid mixer differential mod consisted of:

- replacing (2) existing p/n F7 bellcranks with (2) new p/n F7a bellcranks (the new bellcranks have noticeably more curve, as seen in the attached comparison).

- replacing (2) p/n F37 straight ~2-1/2" long threaded-end rods with (2) new p/n F37a bent ~5" long threaded-end tube rods.

I've also attached a pic of the (unpainted) F7a and F37a modification parts installed in my old Mk-IV mixer.