I appreciate all the replies. The first time I flew this plane it was balanced on a CG machine so that it was neither nose or tail heavy. I am not a seasoned pilot and the plane was totally uncontrollable and people were running for cover. Other flyers suggested adding weights to make it nose heavy and then it responded well. Subsequently I had a rudder issue and it did a "U" turn on takeoff and hit the ground. It had some damage which I fixed and the issue I described above happened subsequently. Taking your advice into account I will shim the motor mount for a little down thrust on the motor with washers and see if this makes a difference. It is still a little nose heavy after removing some weight segments from the tail and putting in a rigid frame landing gear arrangement to replace the flimsy existing wire landing gear which, according to others on this forum is another issue. Prior to reading these three replies I would never have guessed that engine thrust angles would pose a serious issue.