- Fuel and air are ignited by a spark inside the engine's combustion chambers in order to turn a rotor that is attached to the vehicle's driveshaft. This is similar to the operation of a regular piston engine, but a rotary engine has four separate chambers instead of one that drives a single piston. The fuel mixture is shifted from one chamber to the next for each phase of the combustion cycle. The four phases of combustion are intake, compression, ignition, and exhaust.
- The first rotary engines were developed in the 1890s by Stephen Balzer. His company was unable to stay afloat, but other manufacturers picked up the design. The rotary engine sold well until improvements in piston engine design made the rotary model obsolete. In the 1950s, German engineer Felix Wankel began production of a more efficient and reliable rotary engine design, which was initially used in motorcycles before being picked up by Mazda for use in automobiles.
- Because it has far less moving parts than a standard piston engine, a rotary engine is lighter and breaks down less frequently. There are no timing belts, camshafts, valves, or flywheels to deal with. This also reduces the cost of manufacturing, making the rotary engine an economical choice as well as an efficient one. The spinning action of the rotary engine allows it to run at higher speeds and generate more horsepower over a shorter time frame than a comparable piston engine.
- Their light weight makes rotary engines a good choice for use in airplanes or boats, where any added weight drastically affects the vehicle's speed. A rotary engine is less likely to freeze up while operating, so it is also a safer choice for aircraft. Rotary engines may also be found in portable items like chainsaws or generators.
- There are some inherent flaws in the rotary design, however. Over the life of the engine, the fuel and air mixture may start to leak from one combustion chamber into another, which reduces the engine's efficiency. Rotary engines are designed to hold only small amounts of oil, so the oil reservoir must be checked and topped off frequently. This added maintenance and shorter engine life are two of the main reasons that the rotary engine has not become popular for use in automobiles.
