I agree about slowly increasing the elevator until it snaps out, of course that is the limit. There two other thing I do to increase turning. First is weight, every 1/2 ounce makes a noticeable difference, of course this is best done in the building faze. Second and the only thing left to try is to get the iron out and with a weight on the left wing and the right hanging off a table, twist the right wing with one hand CLOCKWISE and iron the wrinkles out of the outer 1/3 of the right wing. Then do the the left wing COUNTERCLOCKWISE. This will create wash out and allow the wing tips to stall at a slower air speed. Try to be sure both wing tips are the same amount of twist for max effect. Good luck.