Aviation: Turboshaft Engine

A gas-turbine engine that delivers power through a shaft to operate something other than a propeller is referred to as a turboshaft engine. The output shaft may be coupled directly to the engine turbine, or the shaft may be driven by a turbine of its own (free turbine) located in the exhaust stream. As mentioned with the turboprop, the free turbine rotates independently. This principle is used extensively in current production of turboshaft engines. The turboshaft engine’s output is measured in horsepower instead of thrust because the power output is a turning shaft.