Prop absorb vs power

[bit]

One question.
The power absorbed by the propeller is:
Diameter^4 x Pitch x Rpm^3 x 1.3 / 1E +14 ?

Example:
Propeller 23" x 14"
1500 RPM = 172 hp
1050 RPM = 59 hp
600 RPM = 11 hp
The calculations are correct?
Thank you, Bit

[jehardiman]

No.

Power absorbed is a function of torque and rpm. Torque is a function pitch, diameter, rpm, and speed of advance. Therefor your equation cannot be correct, though it may be a curve fit of some specific data.

See the following lecture notes.

http://ocw.mit.edu/NR/rdonlyres/D5F21440-9EC4-4104-A081-E03D8784D82A/0/02propeller_test.pdf