In the rearview mirror: NSU puts the first Wankel on the road

It may have been relatively small, but it was a star of the 1963 Frankfurt Motor Show: 60 years ago, NSU presented the world's first production car with a rotary piston engine, the Wankel Spieder. It rolled off the production line in 1964 - and after just three years, it was gone again. Nevertheless, NSU wrote automotive history with this small sports car.

The company had been in contact with designer Felix Wankel at an early stage. The first result of this cooperation was a rotary-slider-controlled 250-cubic motorcycle engine based on the NSU Lux and Max models. However, as a strong trend towards automobiles was emerging in the mid-1950s, the focus soon turned to developing power units for cars. Wankel had taken his idea further and designed it as a rotary engine; in this, a pointed oval piston rotates in a likewise rotating, almost circular body. NSU extended the contract with Felix Wankel - the aim of the collaboration was to develop rotary piston engines, abbreviated DKM. On February 1, 1957, the DKM 54, the world's first rotary engine, ran on the test bench in Neckarsulm. It stood out for its smooth running. However, after 15 hours on the test bench, the first sealing problems appeared. And so the development engineers at came to the conclusion that the engine concept had to be fundamentally revised.

To reduce the complexity of the principle and simplify the technology, the piston in the successor unit rotated in a fixed housing. At the beginning of 1959, the KKM 250 underwent its first tests on the test bench. After further improvements, the engine was finally used as a test vehicle in an NSU Prinz in the summer of that year. A short time later, the engineers installed the successor KKM 400 engine in an NSU Sport Prinz a little later.

In September 1963, the time had finally come: shortly before the International Motor Show in Frankfurt, the Neckarsulm plant stood still for an hour as Dr. Gerd Stieler von Heydekampf, then Chairman of the NSU Board of Management, officially presented the "NSU Spider," as it was then officially known, to the employees. The applause was great - and so were the expectations. The new sports car, designed by iconic designer Bertone, was an absolute eye-catcher. At the Frankfurt Motor Show, the car was euphorically celebrated, especially because of its revolutionary engine. The drive was lightweight - with transmission, alternator and starter, the total weight was just 125 kilograms - and required little space. The Wankel was therefore mounted as an underfloor engine in the rear, which meant that the Spider had a trunk in both the front and the rear.

The new Motor impressed experts with its extremely low vibration and, according to NSU advertising, ran as smoothly as a six-cylinder. For many, the engine was quickly known simply as the "Wankel engine". Word of its advantages spread quickly and soon well-known car and engine manufacturers were acquiring licenses for the new rotary engine technology from Neckarsulm - including General Motors, Daimler-Benz, Porsche, Nissan, Toyota and Toyo Kogyo, better known today as Mazda and as the company that is currently reviving the rotary engine in the MX-30 R-EV as a range extender.

The licensing business was profitable for the Neckarsulm company, but sales of its own car were sluggish. The Wankel Spider could be bought one year after its IAA presentation, starting in the fall of 1964, in red or white at a price of around 8500 deutschmarks. By July 1967, exactly 2375 units of the world's first Wankel car had been produced. With a further developed engine based on the Wankel principle, the twin-disc Wankel engine in the NSU Ro 80, NSU made another attempt to establish this engine technology in the same year - again without the hoped-for market success.
A combined special exhibition at the Audi Forum Neckarsulm and the German Two-Wheeler and NSU Museum Neckarsulm will celebrate 150 years of NSU until May 5, 2024. (aum)