OUR "ORIGINAL" STIRLING CYCLE HOT AIR ENGINE This miniature Stirling Cycle Engine measures 7" x 4-1/4" and comes complete with built-in alcohol burner. Red flywheels and chassis mounted on a green base, these all-metal beauties silently running at speeds in excess of 1,000 RPM attract attention and create awe wherever displayed. This model comes completely assembled and ready to run.