Did You Know That?


| November/December 1972



1884 Frick Traction Engine

1884 Frick Traction Engine, very early notice link motion. Courtesy of Wm. Strayer, R. D. 1, Dillsburg, Pa. 17019.

Wm. Strayer

Alvordton, Ohio 43501

Many of the steam traction engine manufacturers built some compound engines. A compound engine uses the steam twice before it is exhausted up the smokestack to increase the draft. The low pressure cylinder generally has about double the piston area of the high pressure cylinder, and gets its steam after it leaves the high pressure cylinder, or no steam direct from the boiler.

The tandem compound has both piston heads on the same piston rod. In the cross-compound, the high and low pressure cylinders are set side by side with two cranks set 90 degrees apart. The Woolf compound was a tandem, and used by many early manufacturers who knew their economy, but later discontinued building them due to paying royalty on the patent, and extra cost of building.

The Woolf patent expired about 1915, and the Port Huron Engine & Thresher Co. used their own name on the cylinder name plate. Although they built a very good simple piston valve steam traction engine, they realized the greater economy of their compounds. They built only tandem compounds the last eight years building engines.

Economy runs made at several thresher reunions about 10 years ago, show a 40 year old 24-75 Hp. Port Huron 'Longfellow' developed a Hp. hour on 20.2 Lbs. of water, and evaporated 8.75 Lbs. of water per pound of coal with a 57.65 Hp. load on the Baker Prony brake.

This economy run compares favorably with a Corliss stationary steam engine. Compared with over a dozen other steam traction engines including Baker Uniflows in these tests, all other engines used an average of over 50 percent more water, and over 100 percent more coal per horsepower hour.