Turboshaft

A gas turbine engine designed to deliver most of its useful output as shaft power rather than jet thrust. It commonly drives helicopter rotors, marine propellers, and industrial machinery.

Gas turbine: A rotary engine that extracts energy from continuously flowing combustion gases to produce shaft work or thrust. A turboshaft is a gas turbine configured to prioritize shaft work over exhaust thrust.
Helicopter: A rotorcraft whose lift and control are produced by powered rotating blades. Turboshafts commonly drive its main rotor through a transmission.
Compressor: A machine that raises a gas’s pressure by adding mechanical work. It pressurizes incoming air before combustion in a turboshaft.
Turbojet: A gas turbine engine that produces thrust mainly by accelerating exhaust through a nozzle. A turbojet directs more energy into jet thrust instead of a driven output shaft.
Gas turbine cycle: The thermodynamic cycle in which air is compressed, heated by combustion, and expanded through a turbine. This cycle supplies the energy that the turboshaft converts into rotation.
Turboprop: A gas turbine engine that drives an aircraft propeller through a reduction gearbox. It also converts turbine power into shaft work, but uses a propeller for propulsion.
Combustion chamber: A chamber in which fuel burns with compressed air to produce hot gas. Its hot gas drives the turbine stages that supply shaft power.
Turbofan: A gas turbine engine in which a fan accelerates bypass air to produce much of its thrust. A turbofan’s primary output is propulsive thrust, unlike a turboshaft’s shaft power.
Free power turbine: A turbine stage mechanically independent of the gas generator that extracts power from its exhaust flow. Many turboshafts use this separate turbine to drive the output shaft at load-dependent speed.
Marine propulsion: The systems that generate and transmit thrust to move a vessel through water. Turboshafts can drive marine propellers or waterjets through gearing.

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