Describe a turboshaft engine with no physical connection between the compressor and the power output shaft.

Describe a turboshaft engine with no physical connection between the compressor and the power output shaft.

• A. Free Turbine
• B. Geared Turbine
• C. Turbocharger
• D. Conventional Turbine

Answer: (A)

A turboshaft with no mechanical link between the compressor and the power output shaft is a free-turbine arrangement. Here, there are two separate shafts: a gas-generator turbine that drives the compressor, and a separate free power turbine that drives the helicopter rotor through a gearbox. Because the power turbine is not connected to the compressor shaft, the rotor speed can be controlled and changed independently of the compressor’s speed. This decoupling makes starting easier and allows the rotor to respond to power demands without forcing the compressor to follow rotor speed. The energy from exhaust flow drives both turbines, but only the free turbine powers the output shaft, keeping their speeds separate. This is in contrast to designs where a gear or direct shaft linkage ties rotor speed to the compressor. The turbocharger option and the conventional single-sh shaft turbine don’t describe this independent power-turbine setup.

A turboshaft with no mechanical link between the compressor and the power output shaft is a free-turbine arrangement. Here, there are two separate shafts: a gas-generator turbine that drives the compressor, and a separate free power turbine that drives the helicopter rotor through a gearbox. Because the power turbine is not connected to the compressor shaft, the rotor speed can be controlled and changed independently of the compressor’s speed. This decoupling makes starting easier and allows the rotor to respond to power demands without forcing the compressor to follow rotor speed. The energy from exhaust flow drives both turbines, but only the free turbine powers the output shaft, keeping their speeds separate. This is in contrast to designs where a gear or direct shaft linkage ties rotor speed to the compressor. The turbocharger option and the conventional single-sh shaft turbine don’t describe this independent power-turbine setup.