Stefan Gasparin, of Czech Republic, began building CO2 engines in 1972. He designed and built over 60 variations from 1 through 18 cylinders including single-cylinder, inline, opposed flat, “V,” rotary, and radial configurations. He was registered in the Guinness Book of World Records in 1989 for producing the world’s smallest CO2 engine.
The G24NN two-row 18-cylinder radial engine features a bore in each cylinder of 3.175mm and the stroke is 3mm. It weights 53 grams. Only 19 of these engines were built before the company was closed in 2006. This one (#20), was custom built by Mr. Gasparin just for Paul Knapp’s Miniature Engineering Museum in 2011.