coriolis wrote:
I find the aerodynamics of fixed pitch props relatively easy to
understand - the angle of attack varies with both forward speed and RPM.

However, something puzzles me about constant speed prop thrust. I
realise that the blades twist to give a different pitch, and therefore
when you increase MP to maintain the same RPM the blades will be at a
higher helix angle. However, won't the angle of attack (calculated by
the relative wind) by the same? Isn't that the idea? If the prop is at
the same angle of attack, why is the thrust higher? Once again, I know
the pitch is higher, but isn't the angle of attack the important thing
in generating lift (which is what thrust is) rather than simply the
pitch angle? I've seen texts that say you get a bigger bite, but that
doesn't seem to explain why that matters since lift is predicated on
angle of attack.

Anyone have a good explanation?

TIA
I'll give this a shot:
Fixed Pitch Prop:
prop AoA inversely proportional to IAS
prop AoA proportional to prop RPM

Const Speed Prop:
prop AoA inversely proportional to IAS
prop AoA proportional to throttle setting
& therefor shaft HP

Brian W