cutting props
In my experience I have found that cutting a prop to a smaller diameter results in a prop with an effective higher pitch. On a given engine it will turn more rpm, have less pull (static thrust) but more top speed.
Hold a prop on a flat surface by pressing on the hub. Now, sight down the blade from the tip toward the hub. You will notice that the pitch at the tip is lower than at the hub. If you have say a 16x8 prop, the 8 pitch is in the outer half of the blade where the blade is moving the fastest. The inner half of the prop will have greater than an 8 pitch. Cut an inch off each tip to make this a 14 inch prop. You have reduced the area of the 8 pitch in proportion with the higher pitch inner half. This effectively gives the prop a higher pitch rating.
We all know that lower pitch results in more thrust. So, cut off the flat tips and increase the pitch, but reduce the thrust.
I have tested this on my bench setup several times. If you want more top speed, cut down a prop. If you want more pull, go to a larger diameter prop and/or lower pitch.
Don't take the 50/50 relationship to be an absolute. It varies with each prop design. But the theory holds up the same.
Just my $.02.