Interesting info Gene. 8)
I use an ART pitch guage, which is the dial indicator type. I must admit I dont try to measure the pitch over the whole blade of a prop at once, I use the guage at the 5 degree setting and measure small sections of the blade, particularly the leading and trailing egde.
I feel that the 'pitch' of a prop as listed by the manufacturer is a pretty arbitrary thing, and not neccessarily that useful.
I have measured most of my props on the guage looking at small portions of the pitch and have observed a few things. Mono props tend to have a lot of pitch progression, ie start a low pitch, finish at high pitch. The really fast rigger props tend to have less pitch progression. For example a 2170 has about 5" at the leading edge and a bit over 6" at the trailing edge, while a large X series prop migh have about 3.5" at the leading edge and over 6" at the trailing edge. I used to wonder how tradional hydro props like 14 series could be used on mono's after being cupped. The cupping effectively gives them the large pitch progression while reducing the lift.
What does this mean for modifying props? Not sure yet. Merely getting the pitch progression of one prop and applying it to another does not necessarily make a good prop. But it must be a factor.
Nitrocrazed racing: We will build a better pitch guage....
