## All Cars with Rotary Engines
A rotary engine is a type of internal combustion engine that uses a rotor that spins within a figure-8 shaped chamber to convert pressure into rotating motion. This differs from the more common reciprocating piston engine, which uses pistons moving up and down within cylinders to convert pressure into rotating motion.
Rotary engines have a number of advantages over reciprocating piston engines, including:
* **Smoother operation:** Rotary engines have no reciprocating parts, which makes them smoother and quieter than reciprocating piston engines.
* **Higher power-to-weight ratio:** Rotary engines are more compact and lightweight than reciprocating piston engines, which gives them a higher power-to-weight ratio.
* **Lower emissions:** Rotary engines produce fewer emissions than reciprocating piston engines, due to their more efficient combustion process.
However, rotary engines also have some disadvantages over reciprocating piston engines, including:
* **Lower fuel efficiency:** Rotary engines are less fuel efficient than reciprocating piston engines, due to their higher compression ratio.
* **Shorter lifespan:** Rotary engines have a shorter lifespan than reciprocating piston engines, due to the wear and tear on the rotor and chamber.
* **More complex design:** Rotary engines are more complex to design and manufacture than reciprocating piston engines.
Despite their disadvantages, rotary engines have been used in a number of production cars, including:
### Mazda RX-7
The Mazda RX-7 was a sports car produced by Mazda from 1978 to 2002. It was the first production car to use a rotary engine, and it remained the only production car to use a rotary engine until the Mazda RX-8 was introduced in 2003. The RX-7 was a popular sports car, and it was praised for its smooth operation, high power-to-weight ratio, and low emissions.
### Mazda RX-8
The Mazda RX-8 was a sports car produced by Mazda from 2003 to 2012. It was the second production car to use a rotary engine, and it was the only production car to use a rotary engine after the Mazda RX-7 was discontinued in 2002. The RX-8 was a popular sports car, and it was praised for its smooth operation, high power-to-weight ratio, and low emissions.
### NSU Ro 80
The NSU Ro 80 was a luxury sedan produced by NSU from 1967 to 1977. It was the first production car to use a rotary engine, and it was the only production car to use a rotary engine until the Mazda RX-7 was introduced in 1978. The Ro 80 was a technologically advanced car, and it was praised for its smooth operation, high power-to-weight ratio, and low emissions. However, the Ro 80 was also plagued by reliability problems, and it was discontinued in 1977.
### Citroën GS Birotor
The Citroën GS Birotor was a compact car produced by Citroën from 1973 to 1975. It was the only production car to use a Wankel rotary engine, which is a type of rotary engine that uses two rotors instead of one. The GS Birotor was a technologically advanced car, and it was praised for its smooth operation, high power-to-weight ratio, and low emissions. However, the GS Birotor was also plagued by reliability problems, and it was discontinued in 1975.
### Mercedes-Benz C111
The Mercedes-Benz C111 was a concept car produced by Mercedes-Benz from 1969 to 1979. It was the first car to use a four-rotor Wankel rotary engine, and it was one of the fastest cars in the world at the time. The C111 was never put into production, but it paved the way for the development of the Mazda RX-7 and RX-8.
### Future of Rotary Engines
Rotary engines have a number of advantages over reciprocating piston engines, but they also have some disadvantages. However, rotary engines are still being developed, and there is potential for them to become more efficient, reliable, and affordable in the future.
One of the most promising developments in rotary engine technology is the use of hydrogen fuel. Hydrogen fuel burns more cleanly than gasoline, and it produces no emissions. Rotary engines are well-suited to hydrogen fuel, and they could potentially be used to create zero-emission vehicles.
Another promising development in rotary engine technology is the use of new materials. New materials are being developed that are more wear-resistant and heat-resistant than the materials that are currently used in rotary engines. These new materials could potentially extend the lifespan of rotary engines and make them more reliable.
Rotary engines have the potential to be a more efficient, reliable, and affordable alternative to reciprocating piston engines. With continued development, rotary engines could one day become the dominant type of internal combustion engine used in cars.
