OK, I've just re-read your post. You appear to have a version of Hangar 9 P-51 trainer with dual aileron servos. Most of what I said still applies but naturally you know which side the problem is on. Carefully flex the aileron joint and see if you can loosen it up some.

Ken - probably not digitals. I think they'd all be buzzing if they were. I doubt he would have just one digital in the plane, but could.