Motorjet

A motorjet is a rudimentary type of jet engine which is sometimes referred to as thermojet, a term now commonly used to describe a particular and completely unrelated pulsejet design.

The compressed air is channeled into a combustion chamber, where fuel is injected and ignited.

A jet engine also can provide thrust at higher speeds where a propeller becomes less efficient or even ineffective; in fact, a jet engine gains efficiency as speed rises, while a propeller loses it (outside of a certain design range).

Motorjet research was nearly abandoned at the end of World War II, as the turbojet was a more practical solution to jet power, using the jet exhaust to drive a gas turbine and providing the power to drive the compressor without the additional weight and complexity of a piston engine that generated no thrust.

However, metallurgy and understanding of the design of turbines had advanced to a point after World War II where it was feasible to create a turbine to operate reliably in the high-velocity hot-gas environment downstream of the combustor, and the motorjet idea lost favor.