lol, I just looked at a picture of the airplane...
http://image.rcuniverse.com/forum/up...50/Zx71693.jpg
The elevators are about 3 times as big as the little stabs and the ailerons have almost as much chord as the wing!!. SLOW DOWN! You cant fly very fast with a 3D plane with Gigantic control surfaces like that one has. Flutter can do all sorts of things. With that plane if you are using the correct to slightly oversized engine, unless you taking off, flying vertical or doing a blender or a waterfall or something you dont need much throttle at all, probably only 1/4 throttle or less!...... If you are at any attitiude short of 60 degrees take it easy on the throttle and see what happens. That plane was designed to go pretty slow, seriously, keep the airspeed DOWN.