What do propeller numbers mean (e.g. 10x6)?

The first number is the diameter in inches and the second is the pitch in inches. A 10x6 prop is 10 inches diameter with a 6-inch pitch. Pitch means the theoretical distance the prop would move forward in one revolution, like a screw thread.

How do I choose the right prop size?

Match the prop to your motor. Low KV motors (below 1000) suit larger, lower-pitch props (12x6, 14x7). High KV motors (2000+) suit smaller, higher-pitch props (6x4, 7x5). The motor specification sheet will list recommended prop ranges.

What is tip speed and why does it matter?

Tip speed is how fast the propeller tips travel through the air. Above Mach 0.5 (170 m/s), efficiency drops and noise increases significantly. Above Mach 0.7, compressibility effects cause major efficiency loss. Keep tip speed below Mach 0.5 for best results.

Should I prioritise diameter or pitch?

Larger diameter gives more thrust at lower speeds — good for climbing and hovering. More pitch gives more speed at the cost of thrust. Trainers and 3D planes favour large diameter, low pitch. Speed models favour smaller diameter, higher pitch.

ModelCalcs

Propeller Calculator — Prop Matching

Match propeller diameter and pitch to your motor for optimal thrust and efficiency.

Diameter (inches)

Pitch (inches)

Motor RPM (loaded)

How We Calculate This

Calculates theoretical pitch speed, tip speed and estimated static thrust from propeller specifications and motor RPM.

Formula

Pitch speed = Pitch (inches) x RPM / conversion factors
Tip speed = Pi x Diameter x RPM / 60
Static thrust (g) = 4.392e-8 x RPM x Dia^3.5 x Pitch^0.5

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.