Thanks Mike!
Great explaination of desired airflow vs. HP.
Several years ago our aerial applicators mounted gearboxes and longer props
to their round engined Air Tractors. Not only did they reduce the prop
speed and noise but they increased the airflow around the airplane
produceing a better spray pattern.

Jim


No, Helio owners only care about STOL performance. The Helio requires
high
power for takeoff only. Actually what it requires is high static thrust
and
it benefits from a large diameter prop so that thrust flows over more of
the
slats/wing/flaps. The geared engine can use a larger diameter prop
without
the tips going supersonic. Once airborn, the airplane is not going to go
very fast (135-140kts) with its large wing and large exposed wheels no
matter how much power is availible.