What turbine engine is used to drive an output shaft, commonly used in helicopters?

• A. Shaft Turbine
• B. Turboshaft Engine
• C. Jet Engine
• D. Piston Engine

Answer: (A)

Helicopters use a turbine that provides shaft horsepower to turn the rotor through a gearbox. This is achieved with a turboshaft engine, where the gas generator drives a power turbine that is connected to a shaft. The shaft power is what actually rotates the rotor, not jet exhaust thrust. The turbine’s energy is extracted to drive the rotor, and the exhaust is managed so most thrust isn’t produced forward.

That’s why turboshaft is the correct idea: it’s designed to produce powerful, controllable shaft output to drive the rotor. Terms like “shaft turbine” aren’t standard in aviation, and a jet engine would mainly produce thrust rather than rotor power, while a piston engine is a different, reciprocating type.