A rotary engine

Rotary engine

The rotary engine was an early type of internal-combustion engine, usually designed with an odd number of cylinders per row in a radial configuration, in which the crankshaft remained stationary and the entire cylinder block rotated around it...

is a type of internal combustion piston engine used in some early aircraft, motorcycles, and cars. Virtually the whole engine rotates about a fixed crankshaft.

Rotary engine may also refer to:

• Pistonless rotary engine
  Pistonless rotary engine
  A pistonless rotary engine is an internal combustion engine that does not use pistons in the way a reciprocating engine does, but instead uses one or more rotors, sometimes called rotary pistons...
  
   - pistonless internal combustion engines, e.g. the Wankel engine
  Wankel engine
  The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into a rotating motion instead of using reciprocating pistons. Its four-stroke cycle takes place in a space between the inside of an oval-like epitrochoid-shaped housing and a rotor that...
  
  used in some NSU
  NSU Motorenwerke AG
  NSU Motorenwerke AG, normally just NSU, was a German manufacturer of automobiles, motorcycles and pedal cycles, founded in 1873. It was acquired by Volkswagen Group in 1969...
  
   and Mazda
  Mazda
  is a Japanese automotive manufacturer based in Fuchū, Aki District, Hiroshima Prefecture, Japan.In 2007, Mazda produced almost 1.3 million vehicles for global sales...
  
   cars.
• Turbine
  Turbine
  A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
  
   - a rotary engine that extracts energy from a fluid flow
• Windmill
  Windmill
  A windmill is a machine which converts the energy of wind into rotational energy by means of vanes called sails or blades. Originally windmills were developed for milling grain for food production. In the course of history the windmill was adapted to many other industrial uses. An important...
  
   - a rotary engine that extracts energy from wind
• Waterwheel - a rotary engine that extracts energy from water

For internal combustion piston engines with a fixed engine block of radially-mounted cylinders driving a rotating crankshaft, see radial engine

Radial engine

The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...

.