I have to send the plane back to Phoenix models. Tower gave me this number to call 217-398-0007. I was at full throttle and really moving when it happened. the 46 AX is plenty of power in the air just the take offs took very long. The flutter I heard sounded like a helicopter going from moving to hovering or reversing the pitch of the prop and then into my first flat spin to the ground. It seemed like the fuse cracked in half in the air, right below the front of the canopy.