Dimensionning Propeller WAGENINGEN Du-Delta diagram

[Ogrim]

Hello Everyone,
I need further explanation on the dimensionning of a propeller.

My method is the following :
Determine total resistance > assuming total resistance is equal to thrust > calculate Bu > find all coef etc ...

But we always find Bp Delta diagram, but for calculating Bp we need to know the engine power right ?
how do you did it since I want to calculate it at the end ?

Therefore, I would like to find the Bu-Delta diagram (for B.3.35) or understand the way to use Bp-Delta Diagram.
Thank you for your help

 

[jehardiman]

You seem to be missing the point here, both Bp and delta are functions of n. Make the selection of n then Pd is directly solvable from the max eta curve on the Bp-delta chart. With Pd you can use the gearing eta to get Pi.