Yes, mine needed about 2* more right thrust with a Moki 1.20 in it. The best way to tell if it's a thrust issue is to pull exactly vertical and let go of the sticks...see which way it goes...as the airplane slows down, the wing stops flying and the motor takes over, giving you a yaw or pitch. Make sure your rudder trim is centered as well. Oh yeah, mine also needed about 2* of up thrust as well......havent found an ARF yet that was set correctly. One last thing...make sure you stay with the same prop once you get it dialed in, as it will change with different props.......