The German engineer Felix Wankel was granted a patent for his rotary engine in 1929. He began development in the early 1950s at NSU, and completed a working prototype in 1957.
The Wankel engine was hailed by some as the next major step forward in automobile design. It has fewer moving parts than a conventional piston engine, and its rotary motion makes the drive mechanism much simpler. It can be made much smaller than a piston engine, and has an excellent power–to–weight ratio. Unfortunately there were issues with material stress and fuel leaks, and rotary–engined cars earned a reputation for unreliability.
It was in 1964 that NSU offered the world's first Wankel engined car: the Spider. This was withdrawn in 1967 and replaced by another rotary–engined production saloon: the Ro 80, which was in production for ten years. It won a Car of the Year award in 1967, but reliability and sales were disappointing.
The development of the rotary engine was very cost–intensive for NSU, and problems with the seals of the engine rotor significantly damaged the brand's reputation amongst consumers. Engines required frequent rebuilding to replace worn seals, and warranty costs associated with installation of the engine in the Ro 80 destroyed the financial viability of the company. In 1969 NSU was taken over by Volkswagen, and the marque was merged with Auto Union to form Audi's second incarnation.
Meanwhile Mazda had begun collaborating with NSU to develop rotary–engined cars, in a bid to differentiate itself from other Japanese manufacturers. This strategy was successful to an extent, as Mazda's exports increased. The RX series of high–performance cars continued to use rotary engines up to 2012, when the RX–8 was withdrawn after failing to meet European emissions standards. In 2015, the RX–Vision was named "Most Beautiful Concept Car of the Year" at the Tokyo Motor Show.
© Haydn Thompson 2018