Jim Lacey’s article, Tales of a Three-Legged Tilting Tower, in the December 2013 issue of Farm Collector sent me down windmiller’s memorabilia lane. He mentioned the torsion-style vertical spring governor on the U.S. Ace windmill. It had a vane hinge pin inside of the spring. This was a carryover from the earlier open-geared U.S. Model B. It worked like the spring on a mousetrap. After The Ace, the following Model F used the horizontal stretch-spring governor. It worked like the spring on an old-fashioned screen door.
The torsion-type spring was used on the original Aermotor, the open-geared Ideal and Samson mills made by Stover, the prewar Woodmanse and others. One drawback: This type of spring was hard to replace without removing the vane.
Jim mentioned that the Ace was faster on the downstroke than the upstroke. Most pumping mills had this feature. It was usually accomplished by having the pitmans more near the vertical on the upstroke. This gave them more leverage. Because of the angularity of the pitmans, the downstroke was faster. However, one of the features touted by U.S. was that the Ace had no pitmans.
The Ace’s pumping action was achieved by a horizontal slot in the rocker arm. A crank pin fit into this slot. As the crank pin revolved around the shaft, the pin moved back and forth in the slot. This gave up-and-down pumping action to the rocker arm. The angularity of the rocker arm and the proximity of the sliding pin to the rocker arm’s fulcrum provided a faster downstroke.
This idea was not unique to the U.S. Ace. It was used several decades before by Decorah Windmill Co. The 4-foot Hercules that I wrote about in a May 2011 letter to Farm Collector also had this feature. However, the motion was accomplished by a vertical crosshead slide with a horizontal slot for the pin. It was the easiest running windmill I ever saw. However, a windmill that small needed all the power it could get.
Jim mentioned the merits of a three-legged tower. Then why were so many more four-post towers built? Four-post towers were more stable at ground level. I once saw an Aermotor on a three-post tower in a pasture. The ground was apparently soft, and the tower was a precarious 20 degrees out of plumb.
The Ace was probably a replacement head for the mill in Jim’s article. One fault with the tilting tower was that if a gust of wind hit while the tower was in a horizontal position, it would tend to “weather vane” and twist the tower.
The main thing is that Jim and the others saved an Ace windmill. Kudos to them!
A. Clyde Eide,
Apt. 3205, 3801 E. Crest Dr.,
Bryan, TX 77802