Mr. Demont de Puteaux, known for having tried many rotary engines since 1906, proposed another 300 CV rotary at 2,000 rpm in 1912. This engine turned out to be an advance at the time, although no application is known.

"Demont diagram"

-It is a rotary engine with double effect pistons.

-The diameter of the pistons was 175 mm and the stroke 80 mm. The total diameter of the engine was 75 cm.

-The crankshaft was stationary and the crankcase and its cylinders rotated on ball bearings, and the propeller was fixed to the crankcase.

-The mixture was introduced through the hollow crankshaft at the rear. It had 12 face cams at the rear.

-The connecting rods were connected inside the piston tube. It had 6 cylinders.

-We obtained a schematic diagram for the Demont engine, also known as "tubular engine".

-The arrows indicate the direction of cooling air circulation.

-The combustion chambers are in the piston with the larger diameter.

"Demont schematic diagram"

From Appendix 9: We achieved a complete Demont engine design with special cylinders and pistons. An atypical engine as we saw in the main text. (PeT = pl).

“Disposition of the cylinders” (PiP=pl)

“Cylinder and piston” (PiP=pl)

From Appendix 10: An atypical engine presented at the 1914 Paris Air Show.

-Now we have a new schematic diagram of the mentioned engine with details that improve our understanding.

"Demont semi cross-section"

-We see the different piston diameters but also the actuation of the valves with a drum that has tracks in the front part of the crankshaft.

-New real Demont engine diagram with special piston details. It was a 300 CV engine.

"The 6-cylinder Demont engine"