The Grass Chopper Engine


| April/May 1990



Hot air grass chopper

Baby Mitchell is fascinated by Uncle Tea's hot air grass chopper.

In July of 1989 the women folk of our family were busy making plans for our daughter An's marriage scheduled for July 15th, when I received a flyer from the I.R.O.N. (that's Idaho Retrievers of Nostalgia), announcing a meet on that same day in Rigby, Idaho. I told my wife, Darlene, that I was sorry, but I would not be able to make it to the wedding because of the engine meet. POW! Needless to say I did attend the wedding.

In September when the Utah Antique Machinery Association had its big show in Salt Lake City, An, out of courtesy to her father, brought her new husband, Tea Cooper, to our show. Tea had no previous interest in antique machinery. The couple only planned on making quick walk around and staying maybe an hour. They looked at the gas engines, the steam engines, the log sawing, the tractor pulling contest, the thrashing demonstration and the plowing demonstration. I let Tea drive my little steam tractor while I operated my miniature saw mill.

Instead of staying only an hour, they ended up spending the whole day. Not only that day, but they came back and spent all of the next day. Tea was hooked, I mean hooked good on old engines.

After the show Tea told me that he wanted an engine. He didn't particularly care what kind. Old gas engines are not always readily available and are sometimes a little expensive for newlyweds. A model engine would require machine tools. I suggested a hot air engine and gave him a design concept that I had worked up one day during my lunch break. It incorporated readily available materials and for the most part only required household tools to build.

About a week later Tea had gathered various materials and assembled them into this 'Mickey Mouse' looking contraption. The very first time a fire was put into it, it took right off running.

The stove and water jacket are empty tomato cans from Joe Vera's Mexican Restaurant. The displacer cylinder is a discarded propane cylinder. The displacer is an aluminum 'Koala Springs' drink can. The power cylinder came from an automobile shock absorber. The crankshaft turns on ball bearings from a roller skate, and the flywheels are the ends of a rope spool from the hardware store.