NSU Ro80
The Neckarsulmer Strickmachinen Fabrik (sewing machine factory) started to produce cars already in 1906, but ceased in the mid twenties, only to restart production at the end of the fifties.
Their most important claim to fame is that they funded the development of Dr. Felix Wankel, the rotary engine, which had no conventional piston but a sort of triangular shaped rotor that turned around in a circular housing and by creating “spaces” alongside the rotor combustion chambers could be generated. The biggest problem of the engine was always the sealing of rotor against the interior side of the housing, but the big advantage was the abolishment of vertical up and down movement of pistons. This allowed for a very nice willingness to rev and created a turbine like smoothness.
The first series production car was the NSU Wankel Spider, basically a Sport Prinz Coupe, which was partly used as a testbed for the public. This car was presented in 1964 and based on the success, NSU decided to take the plunge with a full sized sedan, which was presented in 1967.
This was the RO80 which was highly acclaimed, and not only for the engine but also for its futuristic design and very potent chassis. The engine was now a bi-rotor version which produced 115 BHP. The 3-speed gearbox was attached to an automatic clutch (torque-converter) to compensate for the relative lack of low-end torque. This, in combination with the inherent characteristics of the Wankel engine, resulted in a rather high fuel consumption, which, especially after 1973, was not a good selling point. The car deservedly got the Car of the Year award for 1967.
The teething problems, again with the sealing of the rotor resulted in many costly repairs (under warranty) but eventual all the problems were sorted out and the car became reasonably reliable. At that time however also NSU’s financial resources had gone back to a very worrying state, and the company was eventually taken over by Volkswagen which did not continue with brand name not with the Wankel experiment, leaving Mazda as the sole producer working along those principles. A short experiment by Citroen also proved less than satisfactory.
Production of the RO80 lasted until 1977 and about 37,400 were made. Many have later been fitted with conventional engines (Ford or Audi) but real believers kept the NSU or replaced it with a Mazda rotary engine.
Here is an example shown at the Concours d’Elegance at the Loo, in 2004