In 1933, Louis Jusseaume and Roland Victor Nicolas Payen obtained patent No. 749304 on the invention of a toroidal (toric) engine for industry, land vehicles, naval and especially for aeronautic use.

-In the aviation version, it is a two-cylinder, four-stroke aircraft engine.

“Frontal cross-section patent drawing”

-It had double ignition with two spark plugs per cylinder. The two cylinders are fixed.

-Modules could be added to form engines with more cylinders and in 2, 3, or more coupled groups.

-They can also be two-stroke cycle engines without controlled valves, which further simplifies the engine and its weight by having fewer parts.

-It can be used with or without a compressor and the same for reduction gear for the propeller speed.

-It has also been studied to run on gasoline, oil, heavy oil, steam, blue gas (Blau-Gas), etc., or with an injection system.

“Side cross-section”

-Can be considered a "semi-rotary" engine according to the patent description.

Author's Note: Payen is also the builder of Payen planes, small planes with a combination of hang gliding and "canard" very interesting. A copy is exhibited at the Musée de l’Air et de l’Espace de Le Bourget.

“A confiscated Payen for study”