ORIGINAL: daveopam
I can't help with the science of it. However I have run both the APC 16x6 and the MA Scimitar 16x6 on a Saito 1.25 mounted to a profile Fusion. On the ground the Scimitar gives an extra 900rpm. In the air the Scimitar jumps out of a hover. The APC is a steady pull.The Scimitar is supposed to make more thrust at a lower RPM. It does feel that way but the lighter wood prop also spools up much faster than the APC. So is the jump from a hover spool up or design related? I tend to believe it is some of each. Now if you sport fly with both props the APC makes the plane fly faster WOT straight and level. Even though the APC turns less RPM. At least when static. So I'm thinking the APC has to be more efficient at higher RPM. After all the spool up is a mute point running along at WOT. This could go back and forth all do I suppose.
David
A differance in prop speed from one prop to another is not an indication of efficieny. It may be a differance in pitch and total area. At any rate if it were from a change in efficiency then the engine would slow down not speed up, because the prop is moving more air and doing more work.