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Inside Mazda

Mazda Cosmo Rotary

Where it all began, the Mazda Cosmo Sport.

50 Years of Revolution

Without the rotary engine, there would probably be no Mazda. And without Mazda, the rotary engine certainly wouldn’t have been in production for nearly 50 years. It was Mazda’s engineers who took Felix Wankel’s unique engine design concept to fruition, and commercial success, five decades ago this year.

A rotary engine is smaller and lighter than a conventional piston engine, with a superior power-to-weight ratio. As it has no reciprocating parts—just a three-sided rotor spinning in a housing—it is quieter and smoother as well. The rotary also offers outstanding performance for a given displacement. This was a big carrot to a company full of car enthusiasts.

Mazda also embraced the rotary in order to be different, a “defy convention” philosophy that continues to this day. In the ‘50s and ‘60s, Japan’s Ministry of International Trade and Industry, the architect of the country’s post-war industrial policy, was trying to make its nascent automotive sector globally competitive. It wanted to streamline the number of carmakers, reasoning that bigger manufacturers would be more likely to compete with U.S. and European heavyweights. Smaller automotive manufacturers such as Mazda were vulnerable to a forced merger.

But a “think different” carmaker, pioneering a bold new type of engine, was much more likely to maintain its independence. Enter the rotary engine: a distinct reason to buy a Mazda—a car that appealed to fans of driving rather than just to those who simply wanted to get from A to B.

The highly lauded, rotary-powered Cosmo Sport (also known as the 110S) of 1967 not only cemented Mazda’s reputation as a small but highly influential carmaker, but guaranteed the company a permanent place in the automotive firmament outside of Japan. Over the following pages, we’ll study the engine’s development, its racing history, and its future.

Mazda Rotary

KENICHI YAMAMOTO The project lead engineer’s hard work was duly rewarded: he later became president and chairman of Mazda.

Overcoming Adversity

While other carmakers had tried and failed to make the rotary engine a success, Mazda doggedly refused to let the challenges of this complex powerplant get in its way. The recurring problem was scratching—nicknamed “devil’s claw marks”—on the inner surface of the engine casing. This was caused by the apex 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.

Mazda’s engineers, led by Kenichi Yamamoto, eventually not only solved the problem with a graphite-aluminum alloy seal, but also overcame other drawbacks, such as excessive oil consumption and a lack of low-end torque. At long last, the rotary engine became feasible in real-world ownership, combining reliability with spectacular power for its size.

This winning combination led to significant sales success for Mazda in the 1970s. Around 100,000 rotary-powered cars were sold in the U.S. in 1972 alone, and the rest of that decade saw half of Mazda’s car production powered by the rotary engine.




Featuring beautiful Bertone-designed bodywork and impressive performance, this was Mazda’s only front-wheel drive, rotary-engined car. As stunning today as it was when it debuted.

The world’s only rotary-powered pickup truck, the REPU was available solely in the U.S. and Canada and boasted Mazda’s 1.3-liter 13B rotary engine. Fifteen thousand were built—the majority of those in 1974.
This minibus was built for the Japanese market and was powered by the 13B rotary engine. The Super-Deluxe model (pictured) could accommodate 13 passengers and the Deluxe model seated 26 people.
2008 MAZDA RX-8
Penned by current Mazda design boss Ikuo Maeda, the RX-8, which first went on sale in 2003, looks every inch a concept car made for the road, with its futuristic profile and “freestyle” doors.


Pistons go up and down, rotaries go round and round…

Suck In the intake phase, air and fuel are sucked into the chamber
Squeeze As the three-tipped rotor turns, it compresses the fuel-air mixture
Bang Spark plugs ignite the fuel, forcing the rotor to turn in its power phase
Blow The exhaust gases are then pushed out by the next turn of the rotor



Driving an immaculate Mazda RX-3 is a great way to experience the rotary engine. This particular 1973 Super Deluxe version features the 1,146cc 12A rotary unit, which puts out around 110 hp—enough to make the RX-3, which weighs less than one ton, very lively indeed. Every sensation is amplified, from the banshee-like wail of the rotary engine at 8,000 rpm to the way the suspension squats down under acceleration and the wood-rimmed steering wheel kicks back over a bumpy road.

The real action begins to happen at 5,000 rpm and keeps happening until long after your cylinder-engine-calibrated brain tells you to shift. The gear lever has a long throw, but it’s a slick, precision movement that’s immensely satisfying when coupled with the mini dance of clutch, brake and throttle-blip evident in a heel-and-toe downshift. It is this feeling of being connected to the driving experience that makes Mazdas such fantastic cars. The racing version of the RX-3 was hugely successful, claiming multiple victories over the Nissan Skyline GT-Rs that had dominated Japanese touring car racing in the early 1970s. A spell behind the wheel of this RX-3 gives you a taste of those triumphs.


Rotary on track

While Mazda’s most famous rotary race win was in the legendary 787B at Le Mans in 1991, there have been numerous rotary racing successes over the years.



Since the rotary engine was put on hiatus following the end of the Mazda RX-8 production in 2012, it’s been left to another type of motor racing to re-ignite interest in rotary power. Enter the world of the Formula D drifting championship, and meet New Zealand’s drift superstar “Mad” Mike Whiddett.

Previously racing a four-rotor Mazda RX-7 and a three-rotor turbocharged RX-8, Mike’s latest steed features his fastest and most ambitious creation yet: an MX-5 ND with a 2.6-liter twin turbo four-rotor engine putting out a terrifying 1,000 hp. Keep an eye out for Mike this year, as he continues in his quest to take the Formula D championship title. With this car, he’s just got to be in with a fighting chance…






In recent times, the rotary engine’s chief bugbear was its relatively poor fuel economy and higher level of emissions compared with the best modern gasoline or diesel engines, including Mazda’s own SKYACTIV powerplants. But when its potential benefits are so striking—light, compact, smooth, quiet, free-revving—surely there is still a future for the rotary engine?

The rotary may indeed be on the verge of a comeback. As the primary power source, it may be comparatively thirstier as revs rise and fall and loads vary. But at constant and optimal rpm, such as experienced by a generator, it is ideal. Little wonder that Mazda has experimented with using these delightfully small engines—one-third the size of a conventional gas or diesel engine—as on-board power generators, or “range extenders.” In 2013, Mazda demonstrated a tiny single-rotor 330 cc unit generating on-board power for an electric Mazda2. Development continues.

There are other future possibilities. Rotary engines can run superbly on hydrogen, the universe’s most abundant element. It’s also very clean: combusting hydrogen produces only water vapor. Mazda built a number of experimental hydrogen-powered rotaries, including a commercially leased fleet of RX-8s for an environmental study undertaken with the Norwegian government.

Regardless of the technical direction the rotary takes in the future, one thing is more than likely: it will be a thing of beauty. At the 2015 Tokyo Motor Show, Mazda showcased the striking RX-Vision sports car concept (above). With the letters RX traditionally known to preface a Mazda rotary-engined model, the RX-Vision quickened the pulses of rotary enthusiasts worldwide. Mazda merely stated at the time that the rotary remained a symbol of the company’s tirelessly challenging spirit, and that rotary engine research and development continues. But from the company that solved the infamous devil’s claw marks and put rotaries on the world automotive map, who would rule anything out?


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