Originally Posted by martini
Another thought just occurred to me, yes bit quiet at work today
Pitch is the displacement of the prop, ie a 21" pitch prop would move forward a theoretical 21" through a solid mass (no slip).
Therefore any DIAMETER prop of a certain pitch would be comparable to another of equal pitch, they'll both move through a solid mass the same distance per revolution. Obviously discounting all the other variables, surface area, cupping, etc.
Or am I talking sh*t again?
Yes! Reducing diameter increases RPM but the ration is variable depending on other factors almost too many to mention!
We have had quite a bit of prop work done for racing over the years and it is a black art - I can guarantee that Steel Developments have more experience than all of us put together, give them the the information and let them recomend the prop for you to fit.
For instance do you know if more bow lift would help? Sometimes a change in model of prop with different characteristics can give you 500 rpm .... but it might make it harder to control in rougher conditions