Ok, I understand the relationship between a prop's pitch and airspeed, but I am having difficulty determining the exact change in static RPM with a change in Pitch. For example, if one knows the static RPM of a prop with a pitch of 58, what will be the static RPM if the pitch of that prop is changed to 53? Does anyone have a reliable formula to predict this? Obviously, the static RPM will be higher, but I need to know exactly how much higher. Anyone?? There is a direct relationship between the airspeed between the two pitches because the pitch is the theoretical distance in inches that the prop will move through the air in one revolution if there were no resistance or drag. So one can calculate the theoretical airspeed in miles per hour. Again, this assumes there is no resistance or drag. But, how does one calculate the change in RPMs with the change in pitch. I do not see a direct numerical calculation here because the active ingredient now is actually the resistance and the drag. HELP?
Charles

A rule of thumb that I’ve heard is 50rpm per inch of prop pitch change - assuming nothing else changes about the prop (like diameter, metal vs composite, etc.)

Here’s a website that doesn’t talk much about static rpm but is pretty informative towards prop selection:

https://www.eaa.org/en/eaa/aircraft-bui ... er-dilemma

Rule of thumb I've heard is about 100rpm for every 3" of pitch change--
so about 33 rpm per inch.