Hi Farr: From what you have written, the servo arm is slipping on the servo output shaft? Both ailerons are slightly down when the servo arm is horizontal with both aileron control arms at a 90 degree angle to the servo arm, is what I understand you are saying. What you have written is that the servo arm splines do not fit with the servo output shaft spines. Next, both ailerons are to be fared with the wing trailing edge when the servo arm is parallel with the wing spar. This adjustment is made by lengthening the servo linkage to each aileron control horn to raise the ailerons to match the wing trailing edge. My purchased used PT-40 had dihedral in the wing, and flew very well getting me through flight training and soloing. Had many hours of enjoyment with it until it stalled to far from the field, and was never found. It really stumps me that the field safety check done by the club safety officer did not spot this problem before attempting the first test flight. I am happy to read that the hard landing did not cause to much damage. Hopefully after the next inspection, your plane will soar like a bird under control, and give you many hours of flying enjoyment. Let us know how your next flight goes.

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