I am planning to build a stunt trainer for a Cox sure start Motor. The plane should be 20" wing span with 120 square inches. The engine will produce about 14,000 rpm with a 6X3 prop.
It will have about 12 oz of static thrust and should fly the plane between 35 = 40 mph. what should the maximum weight be for good stunt trainer flights. I am expecting it to weigh between 8 and 11 oz. all up weight.