The castings and materials of this vacuum motor comes from Bengs Modellbau in Germany.
Building instructions and materials are good quality, however, a dedicated attention is needed during the machining process of the cylinder,piston and the crank as otherwise there is no chance to get the engine run smoothly.
This type of engine is called flame eater or flame-licker, due to the fact that it operates with the help of a flame that enters into the cylinder with the out stroke of the piston. Once the entry of the flame is closed with the help of a sliding valve, hot air get in contact with the air cooled part of the cylinder and causes a sudden drop in pressure that is sufficient to suck the piston to create the exhaust stage.
Width :100 mm
Height : 110 mm
Piston diameter : 16mm
Stroke : 26mm
I have made a one piece crank from steel instead of suggested 4 piece crank from steel and brass and also used double bearings at each side to obtain a better strength against 100 mm flywheels.