Your problems sound like the same thing I experencied with my aerobird. The first thing I would say is to make sure that tail boom is not at a angle not only to the side but also pointing down but it sounds like you already checked that. After my first aerobird took one to many crashes its flight characistics were the same as yours and I was forced to buy a new fuselage whitch runs under $50 and it flew fine. Sorry I don't have a better answer.

Cale