I got a 2M 3-D plane from KMP with a YS 140 on it, its right on the CG and level when you hold it by the prop nut and the tip top of the rudder. When I fly it, the right wing always drops when you pull up alot of elev. it's worse at slow speeds. If you hold the elev. all the way up it drops the right wing then kind of levels off if your high enough while holding up. What causes this right side to drop & is there a way to fix it??? Thanks