Originally Posted by
Yak13
..........The plane flies "unstable" in the roll axis. It tends to increase roll to whatever side it starts banking. It is also extremely responsive to aileron input...........
I would verify how the roll develops when starting from inverted and also knife edge on both sides.
If the roll improves, then it is possible that the CG may be too high for some reason (due to vertical location of engine, battery or fuel tank maybe).
For stable flight, the vertical location of the CG should be at or just below vertical location of the center of lift.
If not, the CG will be trying to over-roll the plane, so it can adopt the lowest point respect to the center of lift.
