I understand that the dynamics change as the plane starts to move forward-this is why I specified static. Yes I also know about H.P. and the relation of of prop pitch and diameter. What I don't understand is at what pitch do I lose efficfency do to the blade being stalled. You say that the speed at which the air is flowing over the blade(RPM) has no baring on stall, just angle of attack, there seems to be something wrong with that-but for this aplication what you say is propably true.

I know that I would take a lot more h.p. to turn the 15 x15 than the 15 x4 12,000 RPM But if the Static thrust measured with the 15 x 4 was 16LBS.

What would you guess to be the static thrust of a:

15 X 1 at 12,000 rpms
15 X 2 at 12,000 rpms
15 X 6 at 12,000 rpms
15 X 8 at 12,000 rpms
15 X 10 at 12,000 rpms
15 X 12 at 12,000 rpms
15 X 14 at 12,000 rpms
15 X 20 at 12,000 rpms

At what pitch does the stall make the prop inefficient at static?