I have been flying my CPP for a while now, about 4 months. Ever since the first few flights it has every now and then had this wierd, interference like problem. Once I get it flying it will start to jump up and down quickly. It's still flyable so I quickly land and usually end the flight short. I thought it was interference so I did all types of checks. I would have the transmitter antenna collapsed and walk 50 paces or so and check all the controls. Then I would spool the motor up to about half throttle and check all the controls. Nothing changes. It always happens when I get off the ground. The latest test I took it up to about 20 or 25 feet and hovered it there. Same results. Forward flight it will act the same way.

Any ideas on what could be wrong or any settings that aren't right? ANY advice on what more to check or verify would be greatly appreciated. Thanks!