Ive got exactly the same issue with an Ikarus shocky. At full throttle its uncontrollable on the roll. Mines a 9x3.8 apc with a kms kbm31/21 motor. Im wondering if the ailerons (and rear surfaces) are too flexible and twisting in the rotating propwash.

Ive used very light 4.4g servos and also wonder if they havent the power to hold the surfaces

Any thoughts?

Windy