Aviation Maintenance Terms beginning with W

Wake

The high-velocity stream of turbulent air behind an operating aircraft engine.

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Wankel engine

See rotating combustion (RC) engine.

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Waste gate

A controllable butterfly valve in the exhaust pipe of a reciprocating engine equipped with an exhaust-driven turbocharger. When the waste gate is open, exhaust gases leave the engine through the exhaust pipe, and when it is closed, they leave through the turbine.

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Watt

The basic unit of power in the metric system. One watt is the amount of power needed to do one joule (0.7376 foot- pound of work) in one second. One watt is 1⁄746 horsepower.

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Wet-sump engine

An engine that carries its lubricating oil supply in a reservoir that is part of the engine itself.

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Wet-sump lubrication system

A lubrication system in which the oil supply is carried within the engine itself. Return oil drains into the oil reservoir by gravity.

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Whittle, Sir Frank

The British Royal Air Force flying officer who in 1929 filed a patent application for a turbojet engine. Whittle’s engine first flew in a Gloster E.28 on May 15, 1941. The first jet flight in America was made on October 2, 1942, in a Bell XP-59A that was powered by two Whittle-type General Electric I-A engines.

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Windmilling propeller

A propeller that is rotated by air flowing over the blades rather than powered by the engine.

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Work

The product of a force times the distance the force is moved.

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Worm gear

A helical gear mounted on a shaft. The worm meshes with a spur gear whose teeth are cut at an angle to its face. A worm gear is an irreversible mechanism. The rotation of the shaft, on which the worm gear locks the spur gear so its shaft cannot be rotated.

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Wrist pin

The hardened steel pin that attaches a piston to the small end of a connecting rod.

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