Turboshaftmotor

A turboshaftmotor, or turboshaft engine, is a gas turbine engine designed to deliver shaft power rather than jet propulsion. It consists of a gas generator, which includes a compressor, a combustion chamber, and a high-pressure turbine, and a separate power turbine connected to an output shaft. The primary portion of the gas energy is extracted by the power turbine to drive the shaft, while the remaining energy is expelled with the exhaust. This arrangement provides a high power-to-weight ratio and is well suited for driving rotor systems and other mechanical loads.

In operation, air is compressed and mixed with fuel in the combustor, producing high-energy gases that expand through the turbines. The gas generator turbine drives the compressor, while the power turbine extracts energy to turn the output shaft. The shaft speed is reduced through a gearbox to match the requirements of the driven load, such as helicopter rotors. Starting is typically achieved with an electric starter or an auxiliary power unit, and lubrication is essential for reliability. Turboshafts are distinct from turboprops, where part of the engine’s power is intended to drive a propeller; in turboshafts the primary output is shaft power, with any surplus exhaust energy usually not used for propulsion.

Applications include helicopters and other rotorcraft, where compactness and rapid throttle response are important. Aero-derivative turboshafts are also used as auxiliary power units or as mechanical or electrical drives on ships and in industrial settings. The design emphasizes high power-to-weight, reliability, and quick transient response, often at the expense of simple overall efficiency in cruise.