Determining Propeller pitch

[kevin aubuchon]

I would like to determine the pitch of my prop on my 9.9HP outboard. If its not a high thrust prop, I would change it. I thought I would measure the forward distance (not circumference) from the beginning to the end of 1 revolution. Anybody have a more exact method (or correct method if I'm wrong)? Thanks in advance.

CD25
kevin aubuchon



kaubuchon@primary.net

[Matt Cawthorne]

Kevin,
Dave Gerr in his book "The Propeller Handbook" outlines the procedure. It involves measuring the blade angle at some radius and plugging it into a formula. I don't have my copy with me so I can't give the formula to you directly. I think that you can determine the advance of the prop by using a 45 degree triangle to figure the radial position where the blade angle is such that the advance is equal to the tangential motion (2*pi*R). On many larger props the diameter and pitch are stamped into the hub. For instance the designation 15RH14 indicates a 15 inch diameter right handed prop with a pitch of 14 inches.

Good luck

I would like to determine the pitch of my prop on my 9.9HP outboard. If its not a high thrust prop, I would change it. I thought I would measure the forward distance (not circumference) from the beginning to the end of 1 revolution. Anybody have a more exact method (or correct method if I'm wrong)? Thanks in advance.

CD25
kevin aubuchon

Mcawthor@bellatlantic.net

[Ed Roberts]

Suggest showing prop to Evinrude/Johnson dealer and saying " Is this a high-thrust prop?"



edwardroberts@sprintmail.com