Rotary Engines: Advantages, Disadvantages, and Uses

Despite not being popular in modern automobiles, rotary engines offer an alternative to conventional reciprocating piston combustion engines. While many automakers are quick to point out the many disadvantages of rotary engines, they also come with distinct advantages. The advantages of rotary engines include their mechanical operation, simplicity, and more. The main disadvantage is their design elements that lead to operational inefficiencies. This blog will explain both the pros and cons of rotary engines and explain why they are beneficial for certain applications.

The first advantage of rotary engines is their mechanical operation. A rotary engine utilizes a triangular-shaped air-cooled rotor to divide the space within an engine, thereby enabling a standard four-stroke cycle of intake, compression, ignition system, and exhaust system. The moving rotor transports fuel to the various engine compartments for each step in the cycle. In this way, rotary engines are similar to reciprocating piston engines. Rotary engines can be built with any number of rotors, just as piston engines can have any number of cylinders. The rotors engage a drive shaft, thereby powering the vehicle's drive mechanism such as the propeller of a plane or wheels of a car.

A second advantage of rotary engines is their mechanical simplicity. Rotary engines contain far fewer parts than a comparable piston engine. This decreases the costs associated with both design and manufacturing, all while leading to decreased weight. Compared to standard reciprocating engines, rotary engines do not have valves, camshafts, rocker arms, timing belts, or flywheels. This decreases weight, lowers the chance of malfunction, and makes for easier repairs. The power-to-weight ratio of rotary engines made them a popular choice in aircraft.

Another advantage of rotary engines is their reduced vibration. The revolutionary motion of rotary engines allows it to operate with much less vibration than piston engines. This allows them to run at higher RPM and produce more power. The final advantage is that, in the event of a breakdown, rotary engines do not seize up. Loss of compression or other causes of engine failure will still result in a significant loss of power, but the rotary engine will continue to run for as long as possible, while a piston engine would stop operation immediately under similar circumstances.

Despite their many pros, rotary engines come with cons as well. For one, rotary engines contain design elements that lead to operational disadvantages. One such disadvantage is leakage between the engine chambers, which is relatively common and results in a loss of efficiency over time. Also, rotary engines are not expected to last as long as traditional reciprocating engines. Furthermore, other design elements cause rotary engines to burn engine oil in small amounts, therefore requiring regular checking of oil levels. Increased maintenance and short lifespan generally make rotary engines more preferable for specific applications rather than mass-production automobiles.

Because of their unlikeliness to seize during operational failure, rotary engines are a much safer choice in aircraft, allowing the pilot to land safely even with a failed engine. While uncommon in automobiles, rotary engines are still found in sports and racing cars, most notably the RX series of Mazda sports cars. This is primarily due to rotary engines’ ability to run at higher RPM and produce more power over a shorter duration. Other applications that utilize rotary engines include go-karts, personal watercraft, gas generators, motorcycles, and chainsaws.

At Sourcing Streamlined, owned and operated by ASAP Semiconductor, we can help you find all types of aircraft rotary engine parts and deliver them with short lead times and competitive prices. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at +1-714-705-4780. Our team of dedicated account managers is standing by and will reach out to you in 15 minutes or less.


November 2, 2022

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