A very early type of jet engine using a compressor driven by an external motor, rather than by a turbine.

A motorjet is a very early type of , with the first design dating from 1910. Like a or , a motorjet draws air in through one or more intakes, passes this air through a compressor, and uses it to burn in a combustion chamber, with the exhaust gases providing thrust. Unlike a turbojet or turbofan, which power the compressor from a turbine in the engine's exhaust stream, a motorjet's compressor is driven by an external motor (which sometimes drives a in addition to the compressor). The need for a second motor to drive the compressor makes motorjets heavier and lower-performing than turbojets or turbofans; as a result, aircraft designed after the mid-1940s have tended to shy away from motorjets.