Hobbies And Interests
Rotating Vanes
The familiar site of a windmill includes the rotating vanes, or sails, turned by the wind. A common number is four with the vanes crossing each other in the middle. Windmills require more vanes than the modern wind turbine which has three blades. It takes more effort to produce mechanical energy as opposed to electricity, the purpose of the modern wind turbine. Once installed these devices require no human effort; the wind does all the work to turn the vanes.
Windshaft
The vanes rotate around a windshaft that turns as the vanes turn. An example of this feature is found in the Outwood Windmill, England's oldest windmill still in operation. It was built in 1665 and weighs around 25 tons. Its top floor house the oak windshaft that holds the revolving sails.
Main Shaft
The Outwood Windmill is an example of a post mill, so named for the one large post, or shaft. Its post is made from one large oak tree. The mill itself is 39 feet high with the sails being 60 feet across. The purpose of the main shaft, or post, is to continue to transfer the wind energy from the sails to the bottom of the windmill.
Uses
Once the wind is blowing and all the parts are turning the mechanical force produced is available for several uses. The Outwood Windmill is currently used to produce flour. Other historical uses for windmills included the Dutch using them to drain water to reclaim land and farmers using windmills to pump water. The concept of the windmill to produce electricity is the basis for the modern wind turbine.