Originally Posted by Nippissing
Now I have to ask the difference between diameter and pitch? And is stainless prop worth it?
Diameter is straightforward; it's the measurement across the prop tip to tip. Pitch is the "angle" of the blades; measured in how far the prop will travel through a solid medium in one revolution. Both pitch and diameter will affect the WOT rpm, bot lowering rpm as they increase. Typically, you'll lose roughly 150-250 rpm per inch of pitch increase, and 100 rpm for a quarter inch of diameter, assuming all else remains equal (which they never do. Ballpark numbers but can be way off.)
Stainless add another level of complexity: blade shapes are usually cupped (reducing rpm vs uncupped for a given blade shape), they are heavier (takes more to spin them), and they deform less (aluminums tend to lose a bit of pitch while running.) Generally, you'll drop an inch or two going from aluminum to stainless assuming the same diameter is used.
My personal feeling is that you should have two (or more) props: A short prop for heavy loads, and a longer one for running light. And a spare in case you hit something (and tools and hardware to change it out.)