What's the best way to tell if the motors are spinning the same speed other than by ear? I first trimmed it so it sounded like they where in sync, but it still pulled to the left. So I kept adding more right trim to compensate and it helped somewhat, but it still wanted to pull to the left., especially under full power. It will be flying level and then it will just roll to the left and down resulting in just plowing steeply into the ground nose first.