I recently restored an Air Command 447. The engine is an overhauled Rotax 447 with a 4 blade Ultraprop, I used McCutchen 25ft blades. The first flight resulted in the copter only rising about ten feet in the air at max power and could not rise any higher. So my questions are - Is this a horsepower problem? Or a prop thrust problem? Or a too heavy or too long blade problem? Any input out there will be a great help!