ok, I know the problem, you need a brushless motor (please get the align420LF with the 25A ESC from Grand rc (in Trex parts-motors section) and the 11T 13T 15T pinnions (bottom link on sig))

Believe me, the internal ESC is overloaded (very common problem with this heli) causing it to fail, not lift off except little hops in 3D mode, and cause glitching, and screeching servos (tail) I wish it didn't have this problem, but, go ask walkera about that. Once you go brushless though it flys pretty stable.