A windmill gear pair can raise the slow sail-shaft speed for a faster output shaft. Enter a speed ratio to compare the output RPM, revolution time and ideal torque tradeoff.
Windmill Form 1 Interactive Calculator
Enter sail RPM and ideal step-up ratio. Results are kinematic and lossless—not wind power, usable torque or mill capacity.
Equation Used
- Sail speed and step-up ratio are entered independently.
- The gear pair is rigid and lossless.
- Torque fraction is reciprocal ratio only.
- Pitch circles are illustrative and tooth form is not designed.
- Wind aerodynamics, load, efficiency, strength and safety are omitted.
Ideal Windmill Gear Step-Up
The connected pitch-circle drawing shows the entered speed increase and opposite mesh direction.
What This Calculator Represents
A single ideal speed-ratio stage.
Ratio comparison
T=60/Nout
tauout/tauin=1/R
Worked Scenario
At 12 rpm and 6.6667:1, ideal stone speed is 80 rpm, period 0.75 s/rev and reciprocal torque fraction 15%.
Assumptions and Limits
No tooth design, losses, wind power, load or structure is calculated.
Frequently Asked Questions
Is ratio a speed increase?
Yes.
Are losses included?
No.
Is torque in N m?
No; only a percentage ratio.
Are teeth selected?
No.
Is sail RPM predicted?
No.
Can this size a mill?
No.
References
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