In general, there are only two types of wind engines: those made of wood, and those made of galvanized steel. Of course, there are style variations to their gearboxes, vanes, sails, and towers that tend to be factory-specific and too numerous to list.
A great resource that profiles and chronicles specific wind engine models is T. Lindsay Baker’s A Field Guide to American Windmills.
The following is a general guide to wind engine capabilities:
Wind engines were originally developed for pumping water from wells and, to this day, pumping continues to be their primary function. Wind engines were necessary for developing railroads in the nineteenth century to power steam engine locomotives; brought fresh water to urban areas for both consumption and fire protection; were an asset to Midwest farmers who no longer had to manually pump and haul water to livestock; and they made settling the West possible by bringing drinking water to otherwise dry lands too far from rivers.
Because strong storms and tornados often disrupt power in areas of Texas, Oklahoma, and elsewhere, wind engines are still preferred over modern, electric pumps. There you will find wind engine manufacturers like Aermotor in operation.
Wind engine remnants can still be found on farms throughout Illinois. In many cases, the sails, motor, and pump are removed, but the tower remains. Wind engine parts are a popular find at antique stores in the state. Those who restore wind engines or collect memorabilia often find parts and literature on the Internet.
Marketing agencies and salesmen for wind engine manufacturers explored the idea of incorporating wind engines in a variety of farm uses. Because of their smaller size, wind engines were unsuccessful in replacing custom windmills completely, since they cannot deliver the power needed to grind grain or saw lumber. Still, they were employed to turn hay balers, presses, and even grain machinery (such as a corn sheller or a grain elevator).
Farm machine windmills were mounted to the rooftops of barns to provide direct power to the machinery within. These were often larger in diameter and designed to turn a wheel, from which a belt could be run to the machines. Though not classified as a wind engine, there are examples of annular-sailed custom windmills that could run multiple machines or grind grain. One such well-photographed mill is the Ruffle Windmill in Haverhill, Suffolk, U.K. (now destroyed).
A few wind engines have been used to make electricity. Probably the most famous example would be the wind “dynamo” of Charles F. Brush, but over the years others similarly experimented with annular-sailed turbines, including Jacobs Wind Electric. Some prototype turbines with annular sails may be seen, but are not very common. See Wind Turbine Types for more information about these.
The wind engines on display at Batavia's Riverwalk are all designed to pump water.
Photo by Tom Haskell
This is among the last surviving Challenge double-wheel engines, one of very few capable of performing the same tasks of a custom windmill.
Photo from The Harden Foundation