formular for pitch??

[georgiaboy]

Is there a formular for the pitch of a prop? Is 1" of pitch per so many inches of prop diameter or what constitues an inch of pitch. Also is there a table or formular for total water displacement per inch of pitch per diameter of prop.
I know there are countless reasons for the performace variations for any given props application but thought I would like to know what a prop displaces in a controled environment.

 

[troypolla]

Re: formular for pitch??

Pitch is just the amount of movement through the water a prop will travel in 1 rotation. Ex. a 15p prop will travel 15 inches through the water in 1 rotation given that slip is 0%

 

[Dhadley]

Re: formular for pitch??

You can work the slip formula backwards to come up with an approximate pitch. You'd have to know about what rpm you're shooting for, the gear ratio and the speed you're looking for. Be realistic.

There's no substitute for experience though. Let us know what ya got -- I'll bet someone here has something similar and can come up with a good starting point.

 

[Silvertip]

Re: formular for pitch??

Here's a link to a prop calculator and there are many more that accomplish the same thing. Search for "prop calculators". A prop works like a wood screw or a bolt and nut in that one turn of the screw or bolt (the prop in this case) results in a given amount of movement through the water. Unfortuantely, the prop is working in a liquid so the pitch for any prop does not take into account the slippage.
http://www.csgnetwork.com/marinepropcalc.html