This is the second time my Tower Trainer has made a U turn on me. I have also had problems keeping it from climbing as well (it is slightly nose heavy). Before this most recently described flight I placed a washers on the two top retaining screws for the motor mount to control upthrust. I cannot see how that would affect the tendency to turn left since it happened once prior to installing the washers. I have also considered putting a washer on the left bottom motor mount (between mount and firewall) as well to try to control the "U" turns along with more vigilance in throttling the airplane. I use a Spektrum DX7 radio and have D/R. Usually I set the rates up at 65%, 75% and 100% and expo at 50% in each of the 3 positions on ail, ele, and rud. I fly only at the lowest rate.
They say that it is through your mistakes you learn but I am growing increasingly unhappy fixing planes after a Sunday afternoon of flying. I have several trainers and most like the Avistar Elite are quite forgiving and help build my confidence. The two planes that I have recently purchased: this Tower Trainer has a tendency to turn left and Nexstar had a strong desire to go right. The Nexstar is now deceased.
I really appreciate this forum and all I continue to learn from it. I very much appreciate all your suggestions and advice.