Sergey Negrub, an engineer from Bashkiria, has patented a concept for a three-mode jet engine that can operate as a turbojet, ramjet, and rocket engine within a single design. The power plant design is intended for flights in the atmosphere and in rarefied layers up to near space.
The key idea is to combine a conical-auger compressor, turbine, and combustion chamber inside a hollow shaft, which allows the engine to change operating modes without completely rebuilding the cycle.
In the first mode, the unit functions as a classic gas turbine engine: air is compressed by the compressor, fuel burns in the hollow shaft, and energy is distributed between the turbine and the nozzle. This ensures takeoff and acceleration in dense layers of the atmosphere, the engineer explains.
In the second mode, the turbine is turned off, and the engine switches to ramjet mode. The air flow enters through the compressor and generates thrust due to the oncoming flow and autorotation of the rotor.
In the third mode, the system switches to the rocket principle of operation: the oxidizer supply from a separate tank is opened, and the combustion chamber inside the shaft begins to operate independently of atmospheric oxygen. This allows the engine to function at altitudes of tens of kilometers and in a rarefied environment.
According to Negrub's idea, this scheme can be used in aerospace air-launch systems, and in the future, for launching vehicles into orbit with minimal involvement of classic rocket stages.