I am building a VQ Models Pilatus PC-6. It is a high wing plane with a straight wing. This model has a flat bottom wing. Other modelers have reported a great tendency for this plane to climb when speed is increased. Some of tried to change the main wing incidence (raised the trailing edge) but had little effect. Others have added down thrust to the motor and had good results. The horizontal stabilizer is set at zero incidence.

My questions are:
1. Is this tendency due to the flat bottom wing (my guess).
2. Can this be properly compensated for without adverse effects on slow, medium and high speed flight?
3. Will a change in the horizontal stabilizer incidence help?
4. What is the best method to correct this problem?

Thanks,
Vic