Steppe Windmill: Sails, Wind Power, Gearing and Millstones

A wooden post mill (vitryak) turning grain into flour · blade-element model of the sails, real gear train and stones

Presets

Wind and turning the mill

Sails

Gearing and millstones

Stone nut (lantern pinion), the brake wheel has 64 cogs

Live readouts

Graphs

Experiment: which sail pitch is best?

How steeply should the sails be set to the wind? The sweep runs the blade-element model for every pitch and compares the best pitch with the analytic optimum (ideal rotor inflow angle minus the best lift-to-drag angle of attack).

Numerical checks

The science

Display

Sun height (time of day)

Drag to orbit, pinch or wheel to zoom, two fingers or right-drag to pan. Sizes are real: the sails span 12 m.