Propeller Pitch Speed Calculator — Theoretical Max Speed

Pitch is the theoretical distance the propeller would advance in one revolution if there were no slippage, like a screw moving through a solid. A 6-inch pitch prop moves forward 6 inches per revolution in theory. Higher pitch = more speed but more load on the motor.

Theoretical speed assumes zero slippage. The propeller always advances less than its geometric pitch because some slip is needed to generate thrust. This calculator applies a (1 − slip) factor: the 75% default means roughly 25% slip, within the typical 10-25% range for a well-matched RC prop. The factor here is a speed-reduction (slip) figure, not the same thing as true propulsive efficiency (thrust power ÷ shaft power), but it is the standard way to estimate real pitch speed.

Tip speed is how fast the outer edge of the propeller moves through the air. When tip speed approaches the speed of sound (Mach 1, ~343 m/s), efficiency drops dramatically and noise increases. Keep tip speed below Mach 0.7 for best results.

Larger diameter provides more thrust at lower speeds (better for takeoff and climbing). Higher pitch provides more speed but requires more power. For slow flyers and trainers, use larger diameter with lower pitch. For speed models, use smaller diameter with higher pitch.