Hi Paul,

Would you know the pitch and diameter of this propeller (see attachment)?

Thanks,

JP

The diameter is 68 inches.

The angle of attack on the back side of the blade 2/3 rds of the way out is
30 degrees. How that translates to prop pitch is unclear as the blade is
twisted. The blades are also bent back.

The gear box ratio is 2.17:1. My guess on the HP is 180.

Paul Lamar


Hi Paul,

Thanks a lot,

Here is the formula for pitch having the diameter and the angle at 3/4
Radius

Diameter        68  ..  68 ..   68 ..   68 ..     68..   68
Pitch              93 ..    89 ..    85 ..   82..      78..   75
Angle             30 ..   29 ....  28 ....  27....  26  ..  25


Formula is Pitch (in) =   2 x R(3/4) x 3.14 x  Tan(30)
Since your angle is going to be a bit less than 30 degrees at 3/4 radius
instead of 2/3 radius
I calculated all values from 25 to 30 degrees.

JP