I got a Fms 1100mm j3 cub for Christmas and the first time I tried to fly it the plane it flipped over to the right and crashed upside down onto the ground.
the motor shaft broke and the motor was replaced and there was no other damage. later I found out the right side of the elevator was moving further than the left side. so i glued the two sides of the elevator together more securely and that seemed to fix the problem. later i tried flying again and it rotated right again but not as severely it was flying for about 10 seconds before it was sideways and it crashed to the ground again. miraculously the was no damage this time!
I have not tried to fly it since.
any help would be appreciated,