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. His 3-cylinder engine has no connecting rods, but rather a bearing on the crankpin that lifts a solid piston like a cam against a pushrod lifter. The engine has a 7mm bore, 4.2 mm stroke, and weighs 33 grams. It is displayed on a wood base with the Gasparin “G” logo and laminated prop.