Windmill Schematic A replica of the first windmill in North America will soon begin construction at the Mid-America Windmill Museum. With th financial support of the Dekko Foundation, the Robertson's Post Windmill has become reality. It's layout is based on plans of a 17th century post mill preserved in Cambridgeshire, England, and also incorporates features of former American Mills. The average size for the simple post mills in the Mid-America region was 14 feet by 12 feet and stood 30 feet high.
Post mills have little gabled cabins pivoted to rotate atop a strong upright post.
On the front were large crossed sails consisting of lattice frames covered in board or canvas. The sails of the windmill have to face into the eye of the wind for the mill to operate effectively. Three types of windmills had evolved in Western Europe and were in common use by the 17th Century and had to meet this requirement. Four such armscaught the air and spun an attached main drive axel, or wind shaft. Inside the cabin the horizontalaxel was geared to a vertical shaft that rotated the grinding wheel.