Variable cycle propulsion device for supersonic airplanes using diverted exhaust gas

The variable cycle propulsion mechanism has a propulsor (1) carrying gas products escaping through a tube creating a thrust, and an auxiliary propulsion unit (14) separate from the propulsor. The auxiliary propulsion unit operate for subsonic flights, landings and take offs and has a gas mechanism passing gas from the main propulsion unit when operating, or switched off for supersonic flights.