ORIGINAL: Jim Thomerson
I think Da Rock's explaination of pitch distribution along the blade is quite optomistic. The usual best is to make a helical pitch prop, where the pitch at any station gives the same forward "screw motion" as any other. And yes people put wash in or wash out to make things better, they hope.
da Rock's explanation was more an observation of what you'll see on any prop and restatement of how the disign is done. And the idea is that any station along the prop is often designed to give the same forward motion as any other. We both seem to be saying about the same thing. so???????????
What seems to be obvious from what everyone has said, including me, is that there is a tremendously complex set of variables concerning a props performance. And it seems to be the observation of quite a few that there really isn't any scientific way to apply what we can buy to what we have on our models.
And Cruncher gave a pretty decent explanation of why that is. Can you imagine what a dyno would cost, and what it'd be like if it was affordable.