The 1/4 scale Cirrus 4-cylinder inline aero engine model is one of six made by Merritt Zimmerman in 1989. It operates on gasoline with oil mixed in for lubrication. Zimmerman also made seventy-five 1/6 scale model Cirrus 4-cylinder engines. (One of the 1/6-scale model also is on display.)
Zimmerman began building miniature engines in the 1940s. He designed and produced his own castings and also did his own machining. At 83, in less than six weeks, Zimmerman designed, built and tested a 1/4-scale model of the 5-cylinder Kinner radial engine. His engine and drawings were published in construction articles in Strictly IC magazine in 1993.
The inline engine has cylinders in a straight row, or in two rows side-by-side. The full-size Cirrus 4-cylinder was commonly used in the Avro Baby (designed in 1918) and the de Havilland D.H. 60 Moth (1930-1936). This engine is 19″-long, 8″-wide, and 10″-high.