How to develop an engine fit for superheroes

Rotary power has been a signature of Mazda innovation ever since the company launched the Cosmo 110S

Andrew Roberts
Tuesday 08 May 2012 19:09

In the 1960s, there was always a sense of deep frustration from reading in the World Car Yearbook about tantalising vehicles that stood little or no chance of ever being officially sold in the UK. In May 1967, a time when an Austin A60 Cambridge could still be yours for less than £900, Mazda began to produce a diminutive and stunningly elegant coupe powered by a twin rotor engine – the first such production car in the world.

The rotary engine had been developed by Felix Wankel in 1957 in conjunction with the West German motorcycle manufacturer NSU. In July 1961, the Japanese machine tool manufacturer Toyo Kogyo bought the rights to the engine. The company had only begun producing cars the year before, with a diminutive 360cc coupe sold under the Mazda brand name, and the company president was keen to gain a technological edge over Toyota and Nissan with a signature engine. One of the first challenges for the company's engineers was developing a replacement for the NSU's cast iron apex seals, which tended to wear out prematurely – resulting in a drastic loss of power and appalling fuel economy. As the legend would have it, a Mazda engineer was idly looking at the carbon tip of his pencil and was immediately struck with inspiration for a new form of rotor coating – a carbon-aluminum hybrid.

Extensive testing also demonstrated that a dual-rotor setup was far superior to the original single-rotor unit in terms of torque stability, so Mazda replaced the NSU's single spark plug with two units – the first mounted in the most logical place to ignite the fuel mixture at the optimum point for low speeds while the second achieved ignition for maximum performance in all weathers. Meanwhile, at the 1963 All Japan Motor Show, NSU launched the Spider – a small, rear-engined, two-seater roadster – becoming the first manufacturer to introduce a Wankel-powered car. At the same event, a brace of Twin Rotor engines were proudly on display at the Mazda stand. There was also another publicity coup d'état when Mazda's president drove into the venue behind the wheel of a twin rotor-powered, front-engined, rear-wheel drive coupe. The styling of the new 110S Cosmo may have sported overtones of the Jaguar E-Type and the Ford Thunderbird, but the coachwork was devised entirely in-house. The Cosmo was theoretically ready for production by January 1965, but Mazda was still constantly refining the project.

In 1966, 60 pre-production models were issued to dealers across Japan for a ruthless evaluation, the Cosmos being driven by literally thousands of drivers for nearly half a million miles to ensure that their forthcoming range-topper was suited for both urban motoring and cruising along the Meishin Expressway. Mazda was also hoping to make sure it's vehicle would be devoid of the clatter that was already all too familiar to owners of the single rotor NSU Spyder.

After three years of intense testing, and 8 billion yen spent on rotary engine research the Cosmo became the second most expensive sports car made in Japan – the first being Toyota's 2000GT – costing the equivalent of £2,600.

The Cosmo's top speed was 115mph and could do 0-60 in 11.5 seconds – performance figures that completely belied its 982cc power plant. The new Mazda boasted rack-and-pinion steering, disc brakes and coil spring suspension up front, while the four-speed transmission fed power to the rear wheels through a De Dion axle with leaf springs and trailing arms. The cabin was fully equipped with telescopic steering, reclining seats and even adjustable extractor vents in the B-pillar – a sharp contrast to the likes of the MGB with its optional heater.

The launch of the Cosmo managed to steal a march on NSU's twin rotor Ro 80 by several months and a 1968 facelift brought a longer wheelbase, a five-speed gearbox, the option of power assisted brakes and a top speed of 120mph. Such a car was destined to be an object of desire rather than an everyday sight – a vehicle worthy of no less a screen superhero than Ultraman. Toyota's 2000 GT may have been in You Only Live Twice, but 007 never actually takes the wheel, whereas the very sight of Ultraman driving his red and white Cosmo regularly caused rubber-suited monsters to surrender on the spot.

Production of the original Cosmo ceased in 1972, after only 1,519 were made, only six of them were sold in the USA. Kenichi Yamamoto, the engineer who led the rotary development project, would eventually become the chairman of Mazda and, to this day, the firm is automatically associated with rotary powered motoring. And with Ultraman leading the Monster Attack Team in his Cosmo 110S.

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