[jdmilla]

50cc Yak 54. CG and thrust seem OK. Gentle downward arc on 45 deg inverted and generally straight vertical climbs. Here's the problem. Full throttle hands-off straight and level flight into the wind. Pull into half loop and fly inverted in the opposite direction and I get a left yaw (left to the ground observer). The only difference I can deduce between upright flight and inverted flight is the angle of attack on the wings and stab. Is this an aileron differential/alignment problem, or maybe elevator alignment? Thanks for any insights.