The Aermotor Windmill - Design History and Evolution

The Aermotor Windmill - Design History and Evolution
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Aeromotor Windmill

The earliest windmills in the United States were imports made by the European colonialists in the mid-19th century. In 1888, Charles Brush developed the first indigenous wind-powered turbine. This turbine had a 56-foot diameter rotor with 144 blades mounted on a 60-foot tower and produced 12 kW of power.

Almost simultaneous to Charles Brush’s windmill, engineer Thomas O. Perry developed another windmill. This windmill had a slightly off-center wind wheel, counterbalanced by a coiled governor spring. The off-centered wheel automatically turns away from increasing wind and slows its speed, and the resultant tension on the spring causes the wheel to return when the wind decreases. A friction brake that tightens when switched off prevents freewheeling. This new “mathematical” windmill learned from the mistakes of previous experiments and incorporated a back gearing that allowed the wheel to make three revolutions for each stroke, resulting in much greater power to lift water, the primary use of windmills at that time. LaVerne Noyes adopted this model and sold such windmills through his Aermotor Company, established in 1888.

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The Path to Dominance

Initially, people received the Aeromotor windmill with skepticism, with the company able to sell just 24 windmills in the first year of operations. Outstanding design, quality of workmanship, and superior performance, however, soon erased the skepticism, and Aermotor sold 20,000 windmills in 1892 alone. Aermotor guaranteed its 8-foot steel windmill to do more work than any 10-foot wooden windmill of the time, and in practice Aermotor did do more work than most of the 12-foot windmills in existence at that time.

Mass production saw prices drop six fold, with 8ft. windmills costing about $25 and 20ft. mills costing about $300.

Aermotor soon dominated the windmill industry across the United States and had an overwhelming majority of the six million windmills installed across the United States during the early part of the 20th century.

Technical Evolution

The Aeromotor windmill has evolved continuously over the years.

The major upgrade came in 1915 when Aermotor introduced its auto-oiled windmill that shifted the demand of regular maintenance from weekly to annually.

This auto-oiled windmill worked on the principle of a main shaft and two pinion gears at opposite ends of the windmill turning the wheel, with the main casting doubling as the oil reservoir. The enclosed gear case facilitated bathing all moving parts with lubricating oil continuously, with the crank gears carrying lubricants to the bearings. A galvanized sheet steel hood protected the head of the mill from dust and the elements.

The earliest models, the 502 and 602, had V-shaped steel arms riveted to curved bar steel rims using steel clips, and Babbitt bearings at the extreme end of the main shaft. The Aermotor 702 launched in 1933 featured replaceable bearings and screw-type wheel arms, with the rear bearings shifting to between the pinions. The Argentinean 702 model windmills that prevailed during the 1970s had spool shaped hubs.

The next major upgrade occurred in 1981 with the launch of a new 802 model. This new model remains similar to the 702 model and incorporates garlock bearings and a fiberglass hood. The 702 model however retains its popularity over 802s, with old reconditioned 702 model windmills still commanding prices almost as high as that of other factory fresh mills.

Aermotor windmills traditionally came in four versions, in six, eight, ten, twelve, fourteen, and sixteen inches sizes. The large 20-inch windmills introduced between 1922 and 1966 weighing forty nine hundred pounds and having a five-gallon oil reservoir found extensive use for deep well plumbing and became a common landmark in the Southwest desert.


Aeromotor WindmillAermotor started diversification as early as 1904 when the catalogue listed a wide range of accessories such as Aeromotor well pumps, wood and metal tanks, power mill equipment such as feed cutters, power saws, corn shellers, and many other specialty items

In 1926, Aermotor launched “Bilby" towers, named after its designer, Jasper Bilby. This inner tower provided an undisturbed instrument platform and found widespread acceptance by the Army Engineer Corps and the Coastal and Geodetic Survey. Aermotor also pioneered the manufacture of electric transmission towers and forest observation towers. Other major products during this period were gasoline engines and electric generators.

Between 1941 and 1946, Aermotor became a subcontractor for Bell and Howell and built precision lens mounts for the highly secret Norden Bombsight.

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Corporate History

Aermotor as a company arrived by 1918 when La Verne Noyes donated nearly two and one half million dollars to establish scholarships at many colleges and universities such as University of Chicago and University of Iowa for veterans of the World War. These scholarships are still available today. La Verne Noyles died in 1919 leaving no direct heirs, and left the Aermotor Company to a tax paying trust, listing 48 colleges and universities as beneficiaries.

The ownership of Aermotor Company changed hands in 1958, when Motor Products, later known as Nautec purchased the company. They moved the manufacturing operations to Broken Arrow, Oklahoma from Chicago and the headquarters to Conway, Arkansas.

During this time, the company started purchasing castings from outside vendors, and by 1970, all castings came from an Argentinean vendor. Later on, the entire manufacturing process shifted to Argentina.

Ownership of Aermotor again changed hands in 1976, when Valley Steel Product Co. purchased the company. They cancelled the licensing agreement with the Argentinean vendor and returned the manufacturing to a dedicated facility in Arkansas.

In 1984, the Valley Pump Group was itself purchased by the Mueller Co. of Decatur, Illinois, who then sold off Aermotor to an investor group. They shifted base to San Angelo, Texas, changed the name to Aermotor Windmill Corporation, and by 1998 sold it off to Kees Verheul.

The many ownership changes notwithstanding, Aermotor has not deviated from its policy of not forgetting about the item once it leaves the warehouse, a fact that supplements the company’s strong sales and after-sales network as major reasons for the continued popularity and acceptance of the Aeromotor windmill.


  1. Aermotor Windmill Company History
  2. History of the Aermotor Windmill