Hi!

I had a similar problem with an Ultra Stick 40. I *did* go through all the instrument & level checking routines and everything seemed close to perfect. I EVEN added weight to the lighter wing so that the plane would balance (laterally) when held up by the prop.

Later, while reducing weight like mad I removed all the wings cap-strips and made holes all over. Much to my surprise, the wood used in one half was completely different from the one used in the other half. After all the "excess wood" was gone, my plane tracked perfectly through loops & similar maneuvers (both wings weighted almost the same by now).

I also thought the problem was a miss-aligned aileron, twisted stab, engine torque, etc .. you name it ... but in the end, none of those theories stood up with reality.

My conclusion was that static balance was the same (because of the added lead in one wing) but dynamic balance was way off (the wing half's CG's where completely off) ..

NOTE: I am not suggesting you do the same as I did, but it might give you some clue on what's wrong