Helicopter Engines Key Terms

Understand these essential helicopter engines key terms as you research helicopter engines

By Angela King, Freelance Writer

Helicopter engines vary based on the type and style you need or prefer. From turboshaft or "gas turbine" engines to piston-powered engines, you need to know the terminology associated with helicopter engines to choose the best engine options for your helicopter.

Whether you own or sell single-engine or twin-engine helicopter models or want to learn how to fix helicopter engines, know these important helicopter engines key terms to ensure you have a firm understanding of the basic parts of helicopter engines.

Turboshaft or "gas turbine" engines

A turboshaft engine, also referred to as a "gas turbine" engine, is a type of jet engine used in most helicopters. In a turboshaft engine, air is compressed and mixed with fuel and then burned or combusted. This combustion runs the compressors and the rotor blades of a helicopter.
Try: Aerospaceweb.org offers more in-depth information on turboshaft and other types of engines.

Piston-powered helicopter engine

The alternative to a turbine helicopter engine, a piston-powered engine uses pistons to initiate combustion rather than a turbine. The more pistons in the engine, the more powerful the engine is--and the heavier the engine. Because of the weight of piston-powered engines, they are considered less reliable than turbine engines and are not as popular.
Try: Hovercontrol.com offers more information on piston-powered helicopter engines.

Airframe and powerplant certification

Airframe and powerplant certification allows a trained and authorized mechanic to service helicopter engines. In order to earn certification, you must enroll in an FAA endorsed and licensed school and pass oral and written examinations.
Try: For further information on airframe and powerplant certification, visit Education Center Online.

Single-engine vs. twin-engine helicopters

A single-engine helicopter uses one turboshaft engine unit to lift and power the helicopter in flight. Twin-engine helicopters, usually larger helicopters with a greater weight load, require the power that two turboshaft engines produce in order to support lift and sustained flight. While single-engines are safe and economical, many pilots need twin-engines due to load or prefer the safety of twin-engines if the first engine fails.
Try: The Association of Air Medical Services offers more information on single and twin helicopter engines.

Torque effect

Torque effect is the effect the direction the main rotors in a helicopter engine has on the direction the helicopter rotates. Torque effect states that a helicopter will rotate in the opposite direction of the main rotors. Helicopters are equipped with tail rotors to combat torque effect.
Try: Read more about torque effect at DynamicFlight.com.

Sprag clutch

A sprag clutch is the key component in a helicopter that takes the power generated by the engine and passes this power to engage and operate the rotors.
Try: Renold offers more information on the function of a sprag clutch.