Dimensionning Propeller WAGENINGEN Du-Delta diagram

Discussion in 'Props' started by Ogrim, Jul 31, 2019.

  1. Ogrim
    Joined: Jan 2013
    Posts: 10
    Likes: 1, Points: 3, Legacy Rep: 13
    Location: Southampton [UK]

    Ogrim Junior Member

    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
     
  2. jehardiman
    Joined: Aug 2004
    Posts: 3,762
    Likes: 1,148, Points: 113, Legacy Rep: 2040
    Location: Port Orchard, Washington, USA

    jehardiman Senior Member

    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.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.