prop question

[aussie]

Originally Posted by Destroyer

Aussie, the primary benefit of a stainless prop is that it is more efficient. If memory serves me correctly, I believe that a 17P Stainless is usually considered to be the same as a 19P Aluminum, all other things like rake and diameter being the same. The general rule of thumb is that you go down in pitch 2 inches when you change from an Aluminum to a Stainless. With Stainless you get more strength with less blade thickness, meaning less drag when the prop spins. Drag costs horsepower just to turn the prop and before thrust comes into play. Also, Stainless will not 'flatten' out like aluminum. Your 18" pitch may be functioning like a 16" at WOT due to pitch flex. The rule of thumb we always had was jump 2" of pitch when switching from alum to stainless. You may lose 100 rpm at WOT when trimmed the same as aluminum, but the cupping on a stainless prop will allow you to trim higher, bringing the rpms's back the same or even a little bit more. So yes, to answer your question, it probably would be right to say a stainless prop of 17 inch pitch would be about the same as a 18-19 inch Aluminum, all other factors being the same.

im only asking from what I read the hole shot should be similar but a wot the aluminum would flex and I would think a steel prop would run smoother from not changing shape . I have 2 props same spec one aluminum one steel ill have to wait and see the benefits in performance myself seeing is believing