Handbuilt from plans found online. This Victorian engine was designed and built in mid 1800s and started the decline of steam engines. Otto is the person that the 4 stroke thermodynamic cycle is named after. Langen designed the roller clutch. The actual historical engine burned lamp gas and ignited using a pilot light like a stove. This model is fired by a chainsaw sized spark plug and 6V automotive coil. The fuel is acetylene being made on demand in the SS cylinder shown in the video. Water drips on calcium carbide similar to old fashioned miners helmets. The throttle speed is governed by the exhaust valve opening. This model was made using a benchtop manual lathe and mill out of castiron, aluminum, brass and steel. The most difficult part was line boring the cylinder ass my 9x20 lathe barely had room for it.