At the 1963 Frankfurt Motor Show - 60 years ago - NSU presented the revolutionary Spider. The car was not surprising for its lines, which corresponded to the Prinz coupé, but for its mechanics. The conventional engine had been replaced by a Wankel rotary engine, so named because it was the work of Fritz Wankel.
Many saw this engine as a great option for the future. So much so that numerous brands paid royalties for the patent and researched this engine. Mercedes, Rolls-Royce, Citroën, Alfa Romeo, Audi, Chevrolet, Nissan, Ford, Suzuki and Toyota tested this type of engine and even Sbarro installed it in a Porsche 914.
Some showed prototypes, like G.M.'s Aerovette. Others, like Citroën - in addition to NSU, of course - marketed it in small series. But the majority only studied it and did some tests, eventually installing it in one of the models they manufactured. Or they used it as a marketing strategy, like Mercedes did with the C111.
MAN analyzed its viability for trucks, with a diesel version. Perkins worked on them and also on nautical engines with a power of up to 4,500 HP.
But everything went to hell at the beginning of the 70s. There were reliability problems - or durability, if you prefer: at 40,000/45,000 km it was already necessary to start changing some parts - and above all they consumed more than a conventional engine. The oil crisis and emissions standards did the rest.
The NSU Ro 80 did not achieve the expected sales (less than 40,000 cars in 7 years) and the brand was saved from bankruptcy by Audi, which tested the engine by installing it in an Audi 100 body to give life to the Audi 200. However However, the commercial version ended up having a conventional 5-cylinder engine.
Only the Japanese at Mazda preserved this track. Until a decade ago, the Mazda RX-8 has been the example of a great and peculiar sports car with a Wankel engine, "the last of the Mohicans." But it stopped selling 11 years ago.
Now, Mazda has launched the MX-30 R-EV, a plug-in hybrid that uses a small Wankel engine as a thermal unit, but exclusively to recharge the battery. More than a hybrid, it is almost an 'extended autonomy electric'
The advantages of the Wankel block are clear. It has fewer parts (it does not require pistons or connecting rods, nor valves or camshaft), it is smaller and lighter, and the lubrication is by a 'mixture' of gasoline and oil, as in 2-stroke motorcycles. Likewise, it not only offers a good level of power and torque but is also smooth to operate.
It is a triangular-shaped rotor but with curved sides, which rotates inside a fixed oval casing. The rotor, rotating on an eccentric axis, drags the fuel mixture and configures combustion chambers of various sizes to offer the typical 4-stroke cycles: intake, compression, explosion and expulsion or exhaust.
Some patents date back to 1925 but it was in 1951 when Felix Wankel began to develop it. Signed by NSU, the company's engineers worked to turn the idea into something practical. The first NSU engine offered 21 HP, still with a single rotor and the casing that also rotated - later a fixed one was chosen.
Mazda, which had been interested in technology from the beginning, showed more powerful two- and three-rotor engines in 1964. It would be the only automobile firm that would preserve these blocks to this day.
Perhaps everything would have remained an anecdote if in 1967 NSU had not taken a giant step with the NSU Ro 80 sedan. A high-end sedan, very advanced in its time both for its lines and for its technology, which was chosen 'Car of the Year in Europe'.
It was front-wheel drive, had four-wheel independent suspension and power disc brakes. Its engine, built by Comotor (a joint venture between Citroën and NSU), mounted two rotors and developed 115 HP. Citroën also launched two models with a rotary block on the market, including a version of the GS with this engine.
At the same time, Mazda launched the Cosmo, a sports car with a rotary engine, in Japan. Mazda was the great promoter of this type of engine, it solved some of its problems and has manufactured more than 2,000,000 vehicles powered by this mechanism. He has even used it successfully in competition. A Mazda 787 B, with a 4-piston rotary block and 700 HP, won the 24 Hours of Le Mans in 1991.
The Cosmo had a double rotor, 491 cc and produced 110 HP. As a result of the first oil crisis, Mazda worked to reduce consumption (they managed to do so by 40%), emissions and solved some of the sealing problems.
This allowed it to launch an entire family of RX models. The RX-7 made a great leap both in the mechanical section (the engine incorporated electronic injection and turbo for the first time) and in the chassis, the first to be designed specifically for a car with a rotating block.
In 1995 the Mazda RX-8 arrived, with 192 and 231 HP versions. And even in 2000 it tested a hydrogen version of the RX-8, an engine that was also tested in the Premacy Hydrogen HE Hybrid.
