Rotary Engine | Britannica

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rotary engine Ask Anything Homework Help Written and fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors History Britannica AI Ask Anything Table of Contents Table of Contents Ask Anything

rotary engine, internal-combustion engine in which the combustion chambers and cylinders rotate with the driven shaft around a fixed control shaft to which pistons are affixed; the gas pressures of combustion are used to rotate the shaft. Some of these engines have pistons that slide in toroidal (doughnut-shaped) cylinders; others have single- and multiple-lobed rotors. Early rotary engines were used in World War I aircraft. They were air-cooled, with cylinders arranged circularly around a crankshaft fastened rigidly to the fuselage. The propeller was attached directly to the circular frame on which the rotating cylinders were mounted. Various inefficiencies in these engines led to their abandonment after the war.

After World War II the development of a new kind of rotary engine reawakened interest. The Wankel is the most fully developed and widely used of the rotary engines. In the Wankel engine the rotor, in the form of an equilateral triangle, rotates with an orbital motion in a specially shaped casing and forms rotating crescent-shaped combustion chambers between its sides and the curved wall of the casing. The three apexes of the rotor are provided with spring-loaded sealing plates that maintain a continuous sliding contact with the concave inner surface of the casing, and the combustion chambers increase and decrease successively in size as the rotor turns. The fuel charge from a carburetor enters the chamber through an intake port, is compressed as the size of the chamber is reduced by the rotation of the rotor, and at the appropriate time is ignited by a spark plug.

Key People: Lawrence Hargrave (Show more) Related Topics: internal-combustion engine Wankel engine rotor (Show more) See all related content

The Wankel engine was first tested for use in automobiles in 1956. It has since come to be used for such industrial applications as driving air compressors, where small, light-weight, high-speed engines with mechanical simplicity are needed. See also gasoline engine.

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