Calculate RPM and prop tip speed
This calculator determines your motor's maximum RPM and propeller tip speed. Prop tip speed is critical for efficiency - tips moving at or near speed of sound create excessive noise and waste power.
Formulas:
Max RPM = 4.2V × Cells × KVTip Speed (Mach) = (Prop Circumference × RPM / 60) / Speed of Sound (343 m/s)Ideal (0.9-1.0 Mach): Best balance of efficiency and thrust. Prop tips stay subsonic for optimal performance.
Low (< 0.7 Mach): Prop tips are slow. You might benefit from larger props or higher KV motors.
High (> 1.0 Mach): Prop tips are supersonic. You'll experience excessive noise and reduced efficiency.
Calculate optimal motor KV for your setup