Invented by German engineer Felix Wankel, and patented by him in 1929, the ingenious Wankel rotary motor was a viable alternative to the ubiquitous internal combustion engine, achieve four strokes – intake, compression, combustion and exhaust – while rotating.
Wankel struck a deal with German motorcycle (and later revived passenger car) manufacturer NSU in 1951, with the Bavarian firm bravely introducing the world’s first Wankel-powered motor car (the NSU Spider) in 1964. As a rotary engine is smaller and lighter than a conventional piston unit, with a superior power-to-weight ratio, it has no reciprocating parts — just a three-sided rotor spinning in a housing — so it is quieter and smoother too, offering outstanding performance for a given displacement. At the time Mazda’s President, Tsuneji Matsuda, quickly recognised the rotary engine’s potential and soon put pen-to-paper on a technical co-operation deal with NSU.
Mazda itself later claimed that “without the rotary engine, there would probably be no Mazda. And without Mazda, the rotary engine certainly wouldn’t have been in production for over 50 years.” As cash-strapped NSU struggled with this new rotary engine (ultimately leading to the Company’s collapse and 1969 absorption into Audi) Mazda’s engineers took Wankel’s unique engine design concept to fruition, and ultimately commercial success.
Mazda also embraced the rotary in order to be different, a ‘defy convention’ philosophy that thankfully still continues in this all-too rare (these days) engineering-led car company. While other car makers had tried (but failed) to make the Wankel engine a success, Mazda doggedly refused to let the challenges of this complex motor get in its way.
The Wankel’s recurring mechanical problem was scratching — nicknamed ‘devil’s claw marks’ — on the inner surface of the rotary engine’s casing, caused by the seals on the triangular rotor juddering, instead of sliding smoothly, against the inner casing. This scoring led to poor seal durability, and caused the early demise of rotary proposals from many other automotive manufacturers, including Citroën, Mercedes-Benz, Ford, General Motors, Nissan and many others.
Led by gifted engineer Kenichi Yamamoto, Mazda eventually solved the Wankel problem with a graphite-aluminium alloy seal, and also cured other drawbacks, such as excessive oil consumption and a lack of low-end torque. At last, Mazda had made the rotary engine realistically feasible in real-world ownership, combining reliability with strong power for its size.
The acclaimed rotary-powered 1967 Mazda 110S Cosmo Sport (as already covered in Bob Murray’s ‘top seven Mazdas’ GRR selection) cemented Mazda’s reputation as a small but influential carmaker, ultimately securing the organisation a permanent place in motoring history. Mazda’s later rotary-powered RX-7 and RX-8 sportsters significantly helped to enhance this reputation and really put Mazda on the map, both models also mentioned in Bob’s top seven.
By the early 1970s, around 100,000 rotary engined Mazdas per annum were being sold in the USA alone, so despite the mid-‘70s fuel crisis, the rest of that decade saw half of Mazda’s total car production powered by the rotary engine.
To complement Bob Murray’s ‘Top Seven’ Mazda models, including the Wankel Cosmo 110S, Savanna RX-7, RX-8 and Le Mans-winning 787B (the first, and to-date, only rotary powered car to win the legendary 24-hour race), here are a baker’s dozen of lesser-known rotary-powered Mazda models to savour.