Culver Propellors - Prop Pitch Calculator

Pitch selection reference guide

View Entire Guide or use our Pitch Calculator below:

*Prop Pitch Calculator*

Engine RPM		engine RPM at cruise
Cruise Airspeed (MPH)		anticipated cruise airspeed
Reduction Ratio (optional)	:1	1.3 or 1.6 or 2.58 etc. (blank for none)
Prop Length (optional)		in inches

Prop RPM
Recommended Prop Pitch		(assumes no "slip")
Tip Speed (Ft/Sec)		(if prop length given)
Tip Speed Mach %		(if prop length given)

Recommended pitch is theroetical as it assumes no "slip".
For very high pitch props (70"-80") the calculated Tip Speed has been adjusted 5%-6% to approximate true helix Tip Speed. Otherwise circular Tip Speed is shown.
Ideal Tip Speed varies depending on the H.P. per square ft of the prop disc.
The efficiency of a propeller is reduced as the tip speed approaches the speed of sound. Beyond 80% of the speed of sound, further increases in RPM has little affect on thrust. Thus, it is important to keep tip speeds below 75%-80% of Mach.