If he slows down his RPM, will his plane drift down? After all he is hovering too. I would think that a large dia X low pitch prop would be the answer. It would require a high RPM, but also will create more HP without causing more torque. I am no expert by any means, but this seems right to me. Example: HP = torque X RPM right? So to get the same HP by decreasing the torque will require more RPM. My 2 cents.

Richard