The whole world was once convinced that the brainchild of Felix Heinrich Wankel (13 August 1902 - 9 October 1988), the Wankel engine, would conquer the world, would mean the end for the engines with bouncing pistons. NOT!
And in fact it has already gone wrong with the Drehkolben engine from Wankel
In his genius he was technically too complex. NSU bought the license rights and developed the case into the highly manageable Rotationskolben engine. And for convenience, it was called Wankelmotor.
The Wankel engine, so named after its manufacturer Felix Wankel, is an engine that does not work with a piston moving up and down in a cylinder and a crankshaft, but it works with a triangular rotor that rotates in a somewhat oval drum. A phase of combustion always takes place on each of the three sides of the rotor at the same time, while the gasoline-air mixture enters on one side, a combustion takes place on the second side (simply by a spark plug, where the spark plug is a rather difficult life) while on the third side the very hot exhaust gases are just flowing away in the muffler.
Simple and compact
In addition to the rotating rotor, there are actually no moving parts in the wobble block and the compact and relatively high-power source seemed ideal for use in cars and motorcycles. And lawn mowers. Moreover, such a Wankel motor runs very nicely without vibration, and that was - certainly in those days when balance shafts were not yet commonplace - a big plus. In short, the Wankel engine would be a resounding success. Yet?
Every advantage ...
But it was not all sunshine and happiness, because - certainly the early - Wankel engines also had serious disadvantages. The fuel consumption was high and, moreover, the engine ran on mixed lubrication (like a two-stroke), so the oil consumption was also serious. There were also problems in the field of materials: the seals on the corners of the rotor caused problems. In addition, with a Wankel engine, relatively much combustion heat is delivered to the engine block, which therefore had to be properly cooled.
That heat, incidentally, was the reason there was once an experimental one Citroën M35 went up in flames. The experimental 'hydraulique' was parked on a dry grass field after a ride. Entirely by its nature the Citroën by squatting. The hot exhaust manifold set fire to the dry grass ...
Yet it was believed
But there were a considerable number of manufacturers (there were more than 30) who also became licensees of the wonder bike. That happened in both the car and motorcycle world.
NSU was the first to launch a car with it in 1964 and their Ro80 would later become an icon. Mercedes and Citroën did a lot of development work, but in the end it was only Mazda that actually continued and until 2012 still delivered a car with a shaky engine. The wankel engine seemed to get many followers in the motorcycle world. In 1974 Hercules came out with the W2000, a compact, light shaky motorcycle. Such an 1800 was made of it.
In the course of the 1970s, the disadvantages of the wankel engine turned out to be greater than the advantages. The Suzuki RE 5 was about the downfall of Suzuki. Only the English Norton seemed too stubborn to throw in the towel quickly. Thanks to Hercules / DKW, they stepped into the shaky world when all other brands had dropped out, and in 1983 they released their fully subsidized Commander. That was also a seperate.