RX-Rated: Mazda’s Early Rotary Cars, Part 1

Mazda has a long history with rotary engines, going back to the Cosmo Sport and R100 of the late 1960s. With the recently announced demise of the RX-8 — the last rotary-engined model still in production — we look back at the origins of the Wankel engine and the history of the early Mazda rotary engine cars: the Mazda Cosmo Sport 110S, Familia Rotary (Mazda R100), and Luce Rotary Coupé (R130).

1971 Mazda R100 coupe badge

FROM CORK TO CARS: THE DAWN OF MAZDA

The company we now know as Mazda dates back to the January 1920 formation of Toyo Cork Kogyo Co. Ltd. (roughly, “Oriental Cork Industrial Company”) in the Japanese city of Hiroshima. The company’s initial business, the manufacture of synthetic cork products, soon fell on hard times and in early 1921, its creditors appointed a new president, 45-year-old Jujiro Matsuda, a fisherman’s son and one-time blacksmith’s apprentice who had previously founded his own firearms company, Matsuda Works.

Matsuda took Toyo Cork Kogyo in new directions, including the manufacture of machine tools and a brief stab at building motorcycles. By 1927, the cork business had been abandoned and the company’s name became simply Toyo Kogyo Co. Ltd.

In 1931, Toyo Kogyo introduced its first successful motor vehicle: the Mazda-GO DA Type truck, a three-wheeled, cargo-carrying motorcycle powered by a 500 cc (30 cu. in.) engine. The “Mazda” trade name, also used by General Electric for a brand of light bulbs, was selected primarily as an alternative transliteration of “Matsuda,” but it also meant “wisdom” in the ancient Avestan language of the Zoroastrian religion, most commonly associated with the supreme Zoroastrian deity, Ahura Mazda (Lord of Wisdom).

Initially distributed by Mitsubishi, the little Mazda three-wheeler sold well both before and after World War II, spawning several follow-on models and eventually the company’s first four-wheeled truck, launched in 1950. While Jujiro Matsuda had contemplated building automobiles around 1940, the war and subsequent reconstruction tabled those plans and Toyo Kogyo did not offer its first passenger vehicle until 1960.

Like many early Japanese automobiles, the initial Mazda R360 Coupe was a tiny kei car powered by an air-cooled V-twin engine, not vastly different from the motorcycle-engined European “bubble cars” of the time. Nonetheless, the R360 and the subsequent four-seat Mazda Carol, introduced in 1962, were quite successful in the growing Japanese market, briefly making Mazda Japan’s best-selling automotive marque.

1964 Mazda R360 Coupe front 3q copyright 2010 Rex Gray (CC BY 2.0 Generic) modified by Aaron Seversno
A 1964 example of the Mazda R360 coupe, Toyo Kogyo’s first passenger car. Launched in 1960, it was powered by a 356 cc (22 cu. in.) air-cooled two-cylinder engine with 16 hp (12 kW); since the R360 weighed less than 900 lb (about 400 kg), that was enough for a top speed of around 55 mph (90 km/h). At introduction, the R360 cost only ¥300,000, equivalent to about $835. A four-cylinder model, the Mazda Carol, followed in 1962. The R360 was discontinued in 1966, but the Carol survived through 1972. (Photo: “1964 Mazda R360 Coupe” © 2010 Rex Gray; resized and modified 2011 by Aaron Severson and used under a Creative Commons Attribution 2.0 Generic license with modifications offered under the same license)

Despite that success, Toyo Kogyo faced a more serious, long-term threat to its existence. While the Japanese economy was expanding rapidly, the domestic auto industry was still quite small and very vulnerable. With considerable diplomatic pressure to relax import restrictions, Japan’s Ministry of International Trade and Industry (MITI) was contemplating drastic measures to protect native industry from a potential flood of foreign-made cars. One rumored possibility was a consolidation of domestic automakers into as few as three or four major conglomerates, an alarming prospect to smaller companies like Toyo Kogyo, which under such a plan would either disappear or be absorbed into larger automakers like Nissan or Toyota.

Jujiro Matsuda’s son Tsuneji, who had succeeded his father as president in 1951, decided that the only way for Toyo Kogyo to survive as an independent company was to offer products or technology that rivals could not match. Cars like the R360 and Carol were competent efforts, but they were fairly conventional. For the company to have a future, Mazda needed something unique.

WANKEL DREAMS: THE BIRTH OF THE ROTARY ENGINE

Matsuda found his answer two continents away, at NSU-Motorenwerke in Neckarsulm, Germany, which had recently announced a novel new rotary engine co-developed by NSU and independent engineer Felix Heinrich Wankel.

Although Felix Wankel’s name is still closely linked with the rotary engine, it was not a new idea even when Wankel first started working on it in the 1920s. Plans and patents for rotary steam engines had been developed as far back as 1769, although it’s unclear if they were ever built or would have worked if they had been built. Wankel’s own interest in rotary internal combustion engines had begun when he was only 17 years old, stemming from a dream he once had about a car powered by an engine combining the best attributes of piston engines and turbines. He patented his first rotary engine in 1934 while pursuing a related idea, rotary valves for piston engines. Wankel was subsequently commissioned by the German air ministry to apply the latter concept to aircraft engines, work that led to his arrest and a brief imprisonment after the war. He was released in 1946 and eventually resumed his work at a new research lab in the Bavarian city of Lindau.

Felix Wankel 1950s copyright Mazda
Felix Wankel, circa the late 1950s. (Photo circa 1958, copyright and courtesy Mazda)

In 1951, Wankel signed a consulting agreement with NSU to develop rotary valves for motorcycle engines, later followed by a rotary supercharger. (NSU had made automobiles before the war, but sold its auto business to Fiat in 1929 and did not return to passenger car production until 1957.) However, Wankel remained eager to develop a true rotary engine and lobbied strenuously for NSU to underwrite the project. At first, the NSU board was not overly enthusiastic, but by 1954 Wankel had persuaded company management to share the development costs and any patents related to the new engine.

The engine that we now think of as the Wankel rotary was actually a substantial departure from Wankel’s initial early-fifties concept, the Drehkohlbenmotor (DKM, rotary-piston engine). Developed mostly in Lindau by Wankel and his research partner, Ernest Höppner, the DKM featured a trochoidal (triangular) inner rotor with a spark plug set into one face. Both the inner rotor and the rotor housing (sometimes described as an outer rotor) spun around a common stationary center shaft with the combustion process taking place between the two rotating bodies.

DKM prototypes, which first ran in 1957, had excellent volumetric efficiency — particularly considering that the intake charge had to be routed through the center shaft and inner rotor — and could sustain very high speeds with almost no vibration. From a practical standpoint, however, the DKM left much to be desired. Low-speed performance was poor and high rotational inertia made the engine reluctant to change speeds, problematic for anything other than stationary applications. Furthermore, the transmission or output shaft had to be geared to the outer rotor/rotor housing, which was inconvenient from a packaging standpoint. Changing spark plugs required tearing down the entire engine.

1957 Drehkolbenmotor DKM54 stand copyright 2005 Ralf Pfeifer at German Wikipedia CC BY-SA 3.0 Unported
Felix Wankel’s first running prototype Drehkohlbenmotor, the DKM 54, photographed at the Deutsches Museum in Bonn in 2005. (Photo: “DrehkolbenmotorDKM54” © 2005 Ralf Pfeifer at German Wikipedia; resized and used under a Creative Commons Attribution-ShareAlike 3.0 Unported license)

Recognizing those problems, NSU research chief Walter Fröde pushed for an alternative design, the Kreiskolbenmotor (KKM, circuit piston engine), which first ran in mid-1958. In Fröde’s KKM design, a trochoidal inner rotor drove the output shaft via cycloidal gears, causing the rotor to trace an epitrochoidal path (a shape often compared to a peanut or a cocoon) along the inner surface of the rotor housing (see the sidebar on the next page), which unlike in the DKM remained stationary. This approach sacrificed some of the DKM’s smoothness and rev potential as well as posing certain challenges for cooling, but offered much better low-speed behavior and was vastly easier to install and maintain. Wankel was unhappy with the KKM, considering it a cheapening of his concept, but the practical advantages were hard to ignore. The NSU board made it clear that the cash-strapped company could not afford two different rotary designs, so Fröde eventually persuaded Wankel to abandon the DKM.

Even so, the rotary project was a big gamble for NSU and the Neckarsulm firm lacked the resources to fully develop or exploit the new engine on its own. With prototypes running on test stands, NSU started looking for partners and licensees to share the work and the cost. The first was the American aviation company Curtiss-Wright, which in October 1958 paid a reported $2.1 million (plus a 5% per-engine royalty) for exclusive, sublicensable U.S. rights. Over the next few years, NSU would receive more than 100 other license requests covering everything from lawnmower engines to heavy-duty diesel applications.

When Tsuneji Matsuda heard about the rotary engine in late 1959, he concluded that it was exactly what Toyo Kogyo needed. The rotary was mechanically elegant, had great potential, and was radically different from anything else on the road. Matsuda made initial overtures in early 1960 and visited Neckarsulm with a group of engineers that October to see NSU’s development engines and negotiate the licensing agreement. MITI approved the deal in mid-1961. The reported license fee was ¥280 million (about $780,000 at the contemporary exchange rate).

The agreement gave Toyo Kogyo the right to use and sell the rotary engine in Japan and Asia. All they had to do now was make it work.

SIDEBAR: Inside the Rotary Engine

The rotary combustion engine — commonly known as the Wankel — is a type of four-stroke internal combustion engine in which the movement of a three-lobed (trochoidal) rotor within a peanut-shaped (epitrochoidal) housing completes the four stages of the combustion cycle. The rotor drives an eccentric shaft through cycloidal gears and the eccentric shaft in turn drives the output shaft, which rotates three times for each revolution of the rotor. The following animation illustrates the process:

Wankel Cycle anim_en copyright 2005 User:Y_tambe CC BY-SA 3.0 Unported
The basic combustion process of a rotary engine. Note that the hypothetical engine illustrated above has its intake and exhaust ports in the rotor housing (peripheral ports). The position of the ports has an effect comparable to the camshaft profile of a reciprocating engine; peripheral ports improve high-speed breathing and power at the expense of low-end torque while side ports (which in this view would be mounted ‘behind’ the rotor in the upper part of the chamber) have the opposite effect. Most NSU rotaries had peripheral ports, but Mazda opted for side intake and peripheral exhaust ports for better idle quality and low-speed response. Dual spark plugs were common but not universal on the production rotary engines. On Mazda rotaries, one plug fired 5 to 15 degrees after the other to promote more complete combustion. (Animation: “Wankel Cycle anim en” © 2005 User:Y_tambe; used under a Creative Commons Attribution-ShareAlike 3.0 Unported license)

As shown in the above animation, the rotary is dramatically simpler than a reciprocating engine. While the rotary does have counterweights at each end of the eccentric shaft to balance the wobble caused by the rotor’s eccentric motion, a Wankel engine has no connecting rods, no crankshaft, and no valves or valve gear. Intake and exhaust are through fixed ports, either in the side plates or in the rotor housing. (Of course, the rotary still requires the same accessories as a piston engine: water and oil pumps, alternator or generator, et al.)

Compared to piston engines, rotary engines have a number of advantages and several serious disadvantages:

PROS

  • Fewer parts: A rotary engine has fewer than half as many parts as a piston engine, which reduces manufacturing costs and (at least in theory) repair and overhaul costs.
  • Light weight and compactness: With no valvetrain, connecting rods, or bulky crankshaft, a rotary engine takes up less space than a comparable reciprocating engine and usually weighs less, benefiting packaging (and often performance and handling as well).
  • Smoothness: Unlike the pistons of a reciprocating engine, the rotors in a rotary engine never change direction and each power cycle has a longer duration than that of a reciprocating engine; both factors greatly reduce vibration. Because of the eccentric motion of the rotor, the rotary is not quite as smooth as is a turbine engine, but rotaries have little of the shake inherent to many piston engine configurations.
  • Rev potential: With excellent volumetric efficiency (which at some speeds can exceed 100%) and relatively low rotational inertia, a rotary engine can rev quickly and reach very high engine speeds.
  • High specific output: A rotary engine can produce more power than a reciprocating engine of the same swept volume (geometric displacement). With the advent of variable valve timing and fuel injection, the difference is no longer as great as it once was, but for many years a rotary engine was considered comparable to a piston engine of two times the rotary’s total geometric displacement. For example, the output of a 995 cc (61 cu. in.) rotary engine was roughly equivalent to that of a 1,990 cc (121 cu. in.) piston engine.
  • Modest octane requirements: Because of the size and shape of their combustion chambers, rotary engines generally have lower octane requirements than do piston engines.
  • Low NOx emissions: Rotary engines tend to have lower combustion temperatures than do piston engines, substantially reducing nitrogen oxide (NOx) emissions.

CONS

  • Ease of manufacture: A rotary engine may have fewer parts than a piston engine, but some components, such as the rotor housing, are complicated or difficult to produce, driving up manufacturing costs.
  • Difficult sealing: With their mathematically complex curves, adequate sealing is challenging and often problematic for rotary engines, from the corner and apex seals at the tips of the rotors to the O-rings between the rotor housings and side plates. Oil sealing is also more complicated than the piston rings of a reciprocating engine.
  • Fuel consumption: Compared to OHV or OHC piston engines, the thermal efficiency of a rotary engine is poor and a certain amount of fuel mixture clings to the chamber surfaces and rotor, where it is eventually forced out the exhaust ports without being burned. As a result, rotary engines tend to be thirsty for their size and output, with high specific fuel consumption (units of fuel burned per unit of power produced per hour). Based on the Society for Automotive Engineers’ thermal equivalency formula, a rotary engine has thermal efficiency (and thus fuel economy) comparable to a reciprocating engine of three times its geometric displacement. By that formula, for example, a 995 cc (61 cu. in.) rotary engine would be about as thermally efficient — and thus about as thirsty — as a 2,985 cc (182 cu. in.) piston engine!
  • Oil consumption: Even with effective oil sealing, rotary engines consume some oil for rotor lubrication, much like a two-stroke engine. Many production rotaries have used metering systems to inject small amounts of oil either into the carburetor or (in later engines) directly into the rotor chamber itself.
  • High HC and CO emissions: The same factors that cause the rotary’s high fuel consumption and low nitrogen oxide emissions contribute to higher levels of unburned hydrocarbon (HC) and carbon monoxide emissions.
  • Higher cooling requirements: The rotary’s low thermal efficiency means that more of the energy of combustion is lost as heat than in most modern reciprocating engines. That waste heat puts a heavier load on both the cooling and oil systems of a rotary engine than with a piston engine of comparable output, requiring greater radiator capacity and sometimes the use of an engine oil cooler.

KENICHI YAMAMOTO AND THE CHATTER MARKS FROM HELL: THE MAZDA ROTARY ENGINE

As elegant and straightforward as it seemed on paper, Toyo Kogyo engineers quickly discovered that the rotary engine had many serious problems. At the time the license agreement was approved, even NSU had yet to build a truly production-ready engine and the early single-rotor prototypes suffered a very rough idle and prodigious oil consumption. Cooling was also problematic and the gap in the water jacket around each spark plug housing produced thermal stresses that would eventually crack the rotor housing.

The biggest problems, however, were with the complex apex and corner seals at each rotor tip. Those seals were responsible for maintaining compression and segregating exhaust gases from the intake charge, but they experienced considerable stress from the combustion process, limiting their useful life; when the seals wore out, the engine suffered dramatic power loss. Few of the early tip seals had anything approaching an acceptable lifespan, usually failing after less than 200 hours of operation. Harder materials lasted longer, but exacerbated another problem: the tendency of the apex seals to leave vicious “chatter marks” on the inner surface of the rotor housing. During the first two years of development Toyo Kogyo reportedly scrapped hundreds, if not thousands of ruined test engines.

Although the Japanese engineers were progressing more quickly than their NSU counterparts were in some areas, the development process was undoubtedly expensive and Toyo Kogyo might well have given up had it not been for the determination of Tsuneji Matsuda. The story among company employees was that the normally implacable Matsuda had actually kowtowed before Toyo Kogyo’s principal financiers while pleading for the resources to continue the rotary project. Whether or not that was true, Matsuda made it clear that he considered the rotary the key to the company’s survival — a commitment that eventually won over even one of the engine’s harshest internal critics, engineer Kenichi Yamamoto.

Yamamoto, born in Kumamoto in September 1922, had received a degree in mechanical engineering in 1944 from the prestigious Imperial University in Tokyo. Conscripted after graduation, he had been commissioned as a naval lieutenant and sent to work with Kawanishi Aircraft at the naval works in Tsuchiura, where he was eventually assigned to work on kamikaze aircraft. When the war ended, jobs for skilled engineers were scarce and Yamamoto ended up as an assembly line worker at the Mazda plant in Hiroshima, which had only recently reopened after being damaged in the American atomic attack. Yamamoto’s articulateness and technical drawing skills (which he had continued to practice) did not go unnoticed, however, so a few years later he was transferred him to engine development, working on the design of Toyo Kogyo’s first OHV engine.

early Wankel engine copyright Mazda
An early rotary engine, possibly a single-rotor NSU engine. In this view, the rotary’s compact dimensions are readily apparent. The engine itself is dwarfed by its air cleaner and carburetor, gearbox, and accessories. (Photo circa early 1960s, copyright and courtesy Mazda)

By his own account, Yamamoto was not pleased when the company licensed the rotary engine in 1961. He considered the rotary conceptually sound, but he was all too aware of the many pitfalls facing any new engine design and saw the whole project as a boondoggle and a waste of resources. Given those doubts, one can imagine his reaction when he learned in April 1963 that he had been reassigned to lead the new Rotary Engine Research Department.

Yamamoto’s first six months in his new job did little to assuage his doubts. Despite the dedication of his hand-picked engineering team, known internally as the 47 Samurai, the rotary’s major problems seemed intractable — particular the chatter marks, whose cause was initially elusive. Nonetheless, Yamamoto decided to give it his best effort, particularly after he heard Matsuda give a speech to Toyo Kogyo suppliers that June, outlining the threat of MITI’s consolidation plans.

By the time Toyo Kogyo exhibited prototypes of the new rotary at the Tokyo Auto Show in October, Yamamoto had become so frustrated and discouraged that he told Matsuda he wanted to resign. Matsuda persuaded him to stay by appealing not only to Yamamoto’s company loyalty, but also to the memory of the siblings they had both lost in the bombing of Hiroshima.

Matsuda rewarded Yamamoto’s perseverance with an infusion of new resources. In 1964, Toyo Kogyo set up a state-of-the-art rotary engine lab with 30 test cells and computers to process the test data, still a novelty in the mid-sixties. Over the next three years, the company would quadruple the size of its rotary engineering staff.

Gradually, Yamamoto and his team came to grips with the rotary’s major flaws. The chatter marks were eventually traced to the apex seals hitting their resonant frequency within the engine’s operating range, which was addressed with changes to the seal design and materials. The apex seals of Mazda’s early production rotaries were self-lubricating pyrographite, impregnated with aluminum for greater strength, which eliminated the chatter marks and provided a useful life of at least 60,000 miles (100,000 km). Meanwhile, better oil seals, developed in partnership with Nippon Oil Seal Co. and Nippon Piston Ring Co., finally reduced oil consumption to a manageable level. By 1967, Toyo Kogyo was finally ready to launch its first rotary-engine production car.

MAZDA COSMO SPORT

To showcase its new engine, Toyo Kogyo decided to develop an entirely new car not based on any existing model. Known internally as Project L402A and later christened Mazda Cosmo Sport, it was the first Mazda sports car: a low-slung monocoque coupe with a very low hood line that took full advantage of the rotary’s compact dimensions.

Although Toyo Kogyo had gone to Italy for some past design work, the Cosmo Sport was styled in-house, looking rather like the bonsai offspring of a 1961 Ford Thunderbird and Chrysler’s 1963 turbine car. Unlike Mazda’s early kei cars, the Cosmo Sport had a front engine and rear-wheel drive. Front disc brakes were standard and the sole transmission was a four-speed manual gearbox.

1967 Mazda Cosmo Sport 110S front 3q
The early L10 Cosmo Sport was 163 inches (4,140 mm) long on an 86.6-inch (2,200mm) wheelbase, standing only 45.9 inches (1,165 mm) high. Curb weight was quoted at 2,024 lb (918 kg). The Cosmo Sport had quick rack-and-pinion steering, but some reviewers criticized it for being numb on center and complained that crosswinds response was less than reassuring. (author photo)

The earliest Cosmo Sport prototypes had a two-rotor engine known as the L8A, with a total swept volume of 798 cc (49 cu. in.). (Unlike NSU, Toyo Kogyo engineers had largely abandoned single-rotor engines, concluding that multiple rotors provided better low-end torque and idle quality. Mazda would briefly explore a return to the single-rotor concept in the 1970s in search of greater fuel economy, although they never offered a single-rotor engine in any production car.) To improve low-speed performance, the L8A had two spark plugs for each rotor, one firing 5 degrees after the other. To manage the separate advance curves for the twin plugs, there were two complete ignition systems, including twin distributors.

The first two running prototypes of the new car were finished by October 1963 and Matsuda actually drove one to the Tokyo Auto Show later that month. However, Toyo Kogyo displayed only the engines at that show, delaying the Cosmo Sport’s public debut until September 1964. According to some accounts, Matsuda opted to wait as a show of respect to NSU, whose first Wankel Spider had debuted in Frankfurt only a few weeks before the 1963 Tokyo show. According to others, NSU pressured Toyo Kogyo to delay the launch and discouraged plans to show the Cosmo Sport overseas, lest it steal the Spider’s thunder.

1967 Mazda Cosmo Sport 110S rear 3q
The Mazda Cosmo Sport had double wishbone front suspension with coil springs, but the rear was a de Dion layout with a fixed differential and a beam axle on semi-elliptical leaf springs, located by trailing links. The unassisted disc/drum brakes were adequate for the Cosmo Sport’s weight, but feel and pedal effort drew some criticism. In response, the L10B cars added a standard vacuum servo. (author photo)

Initially, the L8A had peripheral exhaust ports and a combination of side and peripheral intake ports, which linked to the primary and secondary barrels of the standard four-barrel carburetor. While the additional peripheral intake ports improved high-end power, Yamamoto’s team found them detrimental to low-speed response and idle quality and finally decided to delete them, leaving only the side intakes. That change left the L8A somewhat underpowered, so the engineers increased the rotor diameter, raising total swept volume to 982 cc (60 cu. in.). With a single Zenith-Hitachi four-barrel carburetor, the revised “L10A” engine was rated at 110 PS (108 hp, 81 kW) at 7,000 rpm, with a maximum of 96 lb-ft (130 N-m) of torque at 3,500 rpm.

Toyo Kogyo built about 60 preproduction cars for evaluation in 1965 and 1966, but the Cosmo Sport didn’t actually go on sale until May 30, 1967. It was not only the first production Mazda with a rotary engine; it was the world’s first two-rotor production car, debuting more than four months before NSU’s Ro80 sedan. (Curtiss-Wright had previously tested its two-rotor RC2-60 U5 engine in a modified Ford Mustang, but that engine was never offered for public sale.) Since Toyo Kogyo had only recently revised its license agreement to allow sales of the rotary engine outside Japan, the Cosmo Sport was initially offered only in the home market, with a starting price of ¥1,480,000 (around $4,100). Only a few cars ended up overseas, many of them purchased by other automakers or rotary licensees like Curtiss-Wright, who were eager to figure out what made the Cosmo tick.

1967 Mazda Cosmo Sport 110S L10A engine 1
The yellow, single-snorkel air cleaner marks this as a 110 PS (81 kW) L10A Cosmo Sport; the more powerful L10B had a blue air cleaner with twin snorkels. In either form, the 982 cc (60 cu. in.) engine was very compact and the use of cast aluminum for both the rotor housing and side housings kept dry weight to only 225 lb (102 kg), a full 90 lb (41 kg) lighter than Volvo’s comparably powerful B18 four. Note the twin distributors and ignition coils, common to most Mazda rotaries until 1974. (author photo)

The curious foreign journalists who had the opportunity to test the Cosmo Sport were mostly impressed. It handled well, with quick steering and basically neutral balance, but the real star was the engine. The L10A was not especially quiet (although some reviewers found its exhaust note quite charming), but it was exceptionally smooth and it would rev to 8,000 rpm with an alacrity and enthusiasm alien to most contemporary reciprocating engines. Low-end torque was not abundant, but as engine speeds increased, performance brightened considerably. Reaching 60 mph (97 km/h) took less than 9 seconds and advertised top speed was 115 mph (185 km/h), impressive for a small sports car of the era and faster than many V8-powered American cars.

The Cosmo Sport was not sold in large numbers — only 343 were built between May 1967 and September 1968 — nor was it intended to be. Its construction involved a great deal of hand labor and it’s hard to imagine Toyo Kogyo made any money on it. If the little Mazda coupe was not a profitable exercise, however, it was an effective proof of concept and it drew attention from around the world, including many markets the company had yet to enter.

Even more attention came in August 1968, when Toyo Kogyo entered two Cosmo Sports in the Marathon de la Route endurance race at the Nürburgring. The Nürburgring cars had various engine modifications, including the restoration of the L8A’s auxiliary peripheral intake ports, but were otherwise close to stock. One car was felled by a broken axle during the race, but the other took fourth place, the first flush of a long and often illustrious competition career for Mazda rotaries.

Mazda Cosmo Sport on test track (ID 0255s) copyright 1968 Mazda
The revised Mazda Cosmo Sport on a test track (possibly at Toyo Kogyo’s own Miyoshi Proving Grounds), pursued by what looks to be a new Mazda Familia Rotary Coupé. (Photo circa 1968; copyright and courtesy Mazda)

In September, Toyo Kogyo introduced an updated Cosmo Sport known as the L10B. While engine displacement was unchanged, porting, carburetion, and intake modifications boosted the 982 cc (60 cu. in.) engine to 130 PS (128 hp, 97 kW), comparable to the Nürburgring cars. Externally, the L10B looked little different than before, but the front wheels were moved forward 5.9 inches (150 mm), increasing wheelbase to 92.5 inches (2,350 mm); overall length was actually slightly reduced. (We don’t know the rationale for the change, but it may have been an effort to improve ride quality.) Meanwhile, the gearbox acquired an overdrive fifth gear; a vacuum servo was added to the brakes; the wheels were enlarged to 15 inches (381 mm); and air conditioning was newly optional, mounted on the shelf behind the front seats.

The changes added about 110 lb (50 kg) to the Cosmo Sport’s curb weight, but with the added power, the L10B was even faster than before, with an advertised (and probably conservative) top speed of 124 mph (200 km/h). The revised Cosmo was more expensive as well, with base price rising to ¥1,580,000 (a bit under $4,400). Although the L10B was once again offered only with right-hand drive, a few were officially exported. It appears that most export models used the earlier engine and four-speed gearbox and carried the “110S” identification of the L10A cars.

1967 Mazda Cosmo Sport interior (ID 204) copyright 2007 Mazda
Despite its rocket ship exterior styling, the interior of the Mazda Cosmo Sport (here an early L10A, with four-speed gearbox) was refreshingly no-nonsense, featuring full instrumentation and somber black trim, leavened with a wood-rimmed steering wheel and then-fashionable hound’s-tooth check upholstery. (Photo circa 2007, copyright and courtesy Mazda)

The L10B remained in limited production through the 1972 model year. The Cosmo received a bit of extra publicity in 1971, when the car was featured on the television series Return of Ultraman, and at least one Cosmo Sport was used as a highway interceptor by the Hiroshima Prefecture Police into the mid-1970s. However, the L10B was expensive for the Japanese market and sales rarely topped 200 units a year. The final production tally was 1,176, not including the earlier L10A models.

The Cosmo Sport was an interesting exercise, but it was really only a prelude to Toyo Kogyo’s biggest gamble: the first mass-market Mazda rotary.

RX-85: THE FAMILIA ROTARY AND MAZDA R100

In November 1967, Toyo Kogyo began rolling out the second generation of its compact family car line, the Mazda Familia, originally launched in 1963–1964. The Familia was rapidly becoming the company’s volume product and the new version was the first model slated for export in meaningful numbers. At launch, the Familia was offered only with four-cylinder piston engines, but at the Tokyo Auto Show that fall, Toyo Kogyo exhibited a rotary version of the new coupe, identified as the RX-85 and powered by a de-tuned version of the Cosmo Sport’s 982 cc (60 cu. in.) two-rotor engine.

1968 Mazda Familia Rotary Coupe R100 front 3q copyright 1968 Mazda
An early press photo of the 1968 Mazda Familia Rotary Coupé. The rotary-engined Familia, known as R100 in some export markets, was 150.8 inches (3,830 mm) long on an 89-inch (2,260mm) wheelbase. Shipping weight was 1,775 lb (805 kg), rising to 2,010 lb (912 kg) with a full tank of fuel. (Photo circa 1968, copyright and courtesy Mazda)

The production RX-85, now dubbed Familia Rotary Coupe, arrived in July 1968. To reduce production costs, its 10A engine used cast iron side housings and traded the Cosmo Sport’s chrome-molybdenum eccentric shaft for a cheaper chrome steel unit. With revised porting and carburetor settings, output dropped to 100 PS (99 hp, 75 kW) and 98 lb-ft (132 N-m) of torque, still a healthy improvement on the 59 PS (58 hp, 43 kW) of the Familia 1200’s 1,169 cc (71 cu. in.) SOHC four. In other respects, the rotary car was very much like the Familia 1200, with a four-speed gearbox, MacPherson struts, and a live axle on semi-elliptical springs. Early production models even had the same 10.6 U.S. gallon (40 liter) capacity as the 1200, although on later rotary Familias the fuel tank was enlarged to 13.2 gallons (50 liters) to compensate for the rotary’s greater thirst.

Starting at ¥660,000 (around $1,840), the Rotary Coupe was significantly more expensive than a piston-engined Familia, but also a great deal faster. Toyo Kogyo advertised a top speed of 112 mph (180 km/h) and 0-400 meter (approximately a quarter mile) acceleration in 16.4 seconds; 0-62 mph (0-100 km/h) times were around 11 seconds. Independent testers outside Japan found those figures somewhat optimistic, but the rotary Familia still had brisk performance and there were few other street engines of that time that could happily run to 7,000 rpm. The trade-off was fuel economy. The Familia Rotary’s thirst was not outrageous — in the neighborhood of 20 mpg U.S. (11.8 L/100 km) overall — but it was more comparable to that of six-cylinder engines than of the small fours offered elsewhere in the line. Buyers who expected fuel consumption in line with the 10A’s geometric displacement were to be sorely disappointed, something that would become the rotary engine’s bête noire.

1971 Mazda R100 coupe dash
The well-appointed interior of a Familia/R100 Rotary Coupé. This LHD car is a 1971 U.S. model. (author photo)

SIDEBAR: Rotary Engine Displacement

As with a piston engine, the output of a rotary engine depends a great deal on its swept volume. The displacement of each chamber of a rotary engine is a function of the thickness of the rotor, the rotor diameter, and the eccentricity of the rotor’s motion. In a multi-rotor engine, the swept volume of each rotor is identical, so the engine’s displacement is the swept volume of one chamber times the number of rotors. For example, the early Mazda 10A rotary had two rotors, each displacing a nominal 491 cc (30 cu. in.), for a total geometric displacement of 982 cc (60 cu. in.). Most (though not all) of Mazda’s subsequent production rotaries used rotors of the same thickness as the 10A, but were enlarged by increasing the rotor width (comparable to boring a piston engine), altering the eccentricity (comparable to increasing a piston engine’s stroke), or adding additional rotors.

Since each rotor is beginning its next intake cycle even before the current power ‘stroke’ is completed, a rotary engine produces more power than a reciprocating engine of the same geometric displacement, offset to some degree by lower thermal efficiency; the rotary also consumes more fuel. Calculating the rotary’s equivalence to a reciprocating piston was a matter of some concern for countries like Japan and France, which based vehicle-related taxes and registration fees on engine displacement, and to racing officials, who are generally reluctant to loose a wolf among the sheep. With a geometric displacement of 982 cc, the Mazda Familia Rotary would ordinarily compete in the under-1,000 cc sedan racing classes, but comparing its 100 PS (74 kW) output to the 55 hp (41 kW) of an early 997 cc Mini Cooper suggested that that would be anything but a fair contest.

1967 Mazda L10A engine press image copyright 1967 Mazda
Press image of the early Mazda L10A engine. Although the engine’s geometric displacement was 982 cc (60 cu. in.), the Japanese Ministry of Transportation initially treated it as 1.5 times its actual displacement (i.e., 1,473 cc/90 cu. in.) for tax purposes. For racing, the L10A was generally considered the equivalent of a 1,964 cc (120 cu. in.) piston engine, allowing 10A-powered cars to compete in under-2,000 cc classes. (Image circa 1967, copyright and courtesy Mazda)

Exactly how to compare rotary displacement to that of piston engines was the subject of much debate, beginning almost as soon as the rotary was invented. Because each rotor divides its chamber into three sections of equal size, each of which is simultaneously executing one stage of the combustion cycle, some experts advocated a 3:1 equivalency; even NSU used that formula with its early KKM engines. Most rotary users, however, were understandably reluctant to embrace the 3:1 formula, since it risked making their rotary-engined cars unsalable in certain markets. Most governments and racing officials eventually adopted an equivalency of 2:1, but when the Society of Automotive Engineers issued its official definitions in June 1978 (SAE standard J1220), the SAE hedged their bets with separate formulas for equivalent displacement (2:1) and thermodynamic equivalency (3:1). The latter has largely forgotten, but it does put the fuel economy of early rotary engines in perspective. A 3:1 equivalency would make Mazda’s later 13B comparable to a 3,924 cc (239 cu. in.) piston engine!

1971 Mazda R100 coupe fender badge
The Mazda Familia name was not widely used overseas. Piston-engined export models were generally badged “Mazda 1200,” while the rotary versions were christened Mazda R100. (author photo)

Initial sales of the Familia Rotary Coupe were modest, amounting to only 6,925 units in 1968. In mid-1969, Toyo Kogyo added a four-door sedan, the Familia Rotary SS (presumably for “sport sedan”), with a base price of ¥638,000 (about $1,775), and began exporting the rotary models to Australia and Thailand. Sales expanded to Europe in the spring of 1970.

The Cosmo Sport’s Nürburgring exploits had apparently whetted Toyo Kogyo’s appetite for competition, because the company entered a Familia Rotary Coupe in the Singapore Grand Prix in April 1969, fitted with a 195 hp (145 kW) racing version of the 10A engine. The car won its class, the Familia Rotary’s first racing victory. Three more cars, de-tuned to a still-robust 187 hp (139 kW), entered the Spa-Francorchamps 24 Hour in Belgium that August, taking fifth and sixth. Those cars subsequently headed to the Nürburgring for the 1969 Marathon de la Route, but only one finished the race, taking fifth overall. A Familia Rotary Coupe, tuned for 214 hp (160 kW), won the All Japan Suzuka Automobile Race in November 1969.

The following summer, Mazda R100 coupes competed in the RAC Tourist Trophy and West Germany’s Touring Car Grand Prix before taking a second shot at the Spa-Francorchamps 24 Hour, once again coming in fifth. If not a spectacular success, the racing campaign was a credible effort and paid dividends to later privateers. Many of the pieces developed for the competition cars subsequently became available over the counter in a series of sport kits.

Toyo Kogyo took its first steps into the U.S. market in early 1970, although early sales were limited to the Pacific Northwest. The Familia was part of the initial lineup, offered either with a conventional four-cylinder engine (as the Mazda 1200, in sedan, coupe, or wagon form) or with rotary power (as the R100 coupe). With a starting price of $2,495 POE, the American R100 was $550 more expensive than the conventionally powered 1200 coupe, which had only 64 gross horsepower (48 kW) to the R100’s 100 hp (75 kW). We have no sales breakdowns for the 1970 model year, but total U.S. sales for all Mazda cars and trucks amounted to fewer than 2,500 units. Those sales would grow spectacularly over the next three years.

1971 Mazda R100 coupe front 3q
The Familia Rotary/R100 originally came with the 982 cc (60 cu. in.) 10A engine, which in U.S. trim was rated at 100 hp (75 kW) and 92 lb-ft (125 N-m) of torque. Substituting the larger 12A and 13B engines from later Mazda rotary vehicles is a straightforward swap, providing more power with only a very modest weight penalty; this car is now powered by a later 13B (1,308 cc/80 cu. in.) engine. (author photo)

Export sales, racing success, and the addition of the sedan brought about a healthy increase in total Familia Rotary/R100 production, which climbed from around 28,000 in 1969 to a peak of 31,328 in 1970, representing around 14% of Toyo Kogyo’s total passenger car production that year. The rotary Familia received a number of minor updates late that year, but it was now overshadowed by newer models, and sales for 1971 and 1972 dropped off substantially. The Familia rotaries were withdrawn from Australia in late 1971 and from the U.S. after the 1972 model year, and from the home market in 1973; the redesigned Familiar that bowed that October was not offered with a rotary engine. Total production of the rotary Familias was 95,891 units.

ROTARY RARITY: THE LUCE R130

Alongside the RX-85 at the 1967 Tokyo Auto Show was another prototype, the RX-87, a hardtop coupe loosely based on the Bertone-styled Mazda Luce 1500, which had debuted in August 1966. The RX-87 was decidedly Italianate, looking rather like a cross between an Alfa Romeo Giulia coupe and a second-generation Chevrolet Corvair two-door hardtop.

Under the hood, the RX-87 traded the standard Luce’s 1,490 cc (91 cu. in.) SOHC four for a new 1,310 cc (80 cu. in.) 13A rotary engine. (The 13A was not related to the later Mazda 13B engine; it had different internal dimensions, where the 13B was a straightforward development of the 10A/12A series.) Unlike the Luce, which had a conventional front-engine/rear-wheel-drive configuration, the RX-87 mounted the compact 13A longitudinally ahead of the front wheels, driving a four-speed transaxle — it was Toyo Kogyo’s first front-wheel-drive car.

1970 Mazda Luce Rotary Coupe RX-87 badge copyright 2011 Murilee Martin per
The R130 was formally known as the Mazda Luce Rotary Coupé, but production cars, like the prototype, also wore “RX-87” badges on the rear fenders, just aft of the doors. (Photo © 2011 Murilee Martin; used with permission)

Christened Mazda Luce Rotary Coupé or R130, the production version of the RX-87 went on sale in October 1969. The R130 was the largest passenger car Toyo Kogyo had yet offered, significantly bigger than the Luce sedan on which it was nominally based. The Rotary Coupé’s 13A engine had less power than the smaller engine in the Cosmo Sport L10B, 126 PS (124 hp, 93 kW) at 6,000 rpm, but substantially more torque: 127 lb-ft (172 N-m) at 3,500 rpm.

Like the Cosmo Sport, the R130 had double wishbone front suspension (albeit with unusual rubber torsion springs rather than coils), front disc brakes, and a standard vacuum servo, but the Luce’s rear suspension was independent, with coil springs located by semi-trailing arms. In keeping with its price — ¥1,450,000 (a bit over $4,000) for the base Deluxe model, ¥1,750,000 (around $4,850) for the air-conditioned Super Deluxe — the R130 was well equipped and luxuriously trimmed, with a hefty dose of sound insulation. Toyo Kogyo marketed the R130 as a personal luxury coupe rather than a sports car, but it had brisk performance and a claimed top speed of 119 mph (190 km/h).

1970 Mazda Luce Rotary Coupe front 3q copyright 2010 Jens Kramer per
The 1969–1972 Mazda Luce Rotary Coupé was 180.5 inches (4,585 mm) long on a 101.6-inch (2,580mm) wheelbase with a curb weight of around 2,830 lb (1,285 kg) in Super Deluxe trim. Overall height was 54.5 inches (1,385 mm). The R130 was a true pillarless hardtop, with no B-pillars. (Photo © 2010 Jens Krämer; used with permission)

The R130 was offered only with right-hand drive and we don’t believe it was officially exported, although some eventually ended up in markets like Australia and South Africa. At home, the big coupe’s size, thirst, and high prices made it very rare. Only 976 were built before production ended in 1971. In October 1972, the R130’s place in the lineup was taken by a somewhat smaller, RWD coupe version of the second-generation Luce, sold in some markets as the RX-4.

Surprisingly, Toyo Kogyo never offered another rotary production car with front-wheel drive. The company’s next FWD model, the 1980 BD Familia (323 or GLC in other markets), was offered only with conventional four-cylinder engines.

ROTARY EXPANSION

By 1970, worldwide interest in the rotary engine had increased dramatically, with nearly every major automaker seriously considering rotary power. That November, General Motors signed a $50 million licensing agreement, joining a list of licensees that included not only Curtiss-Wright and Toyo Kogyo, but also Alfa Romeo; Daimler-Benz; Porsche; and the military vehicles arm of Rolls-Royce, which was developing an unusual rotary diesel for main battle tanks. The main attraction was no longer the rotary’s light weight, smoothness, or mechanical simplicity, but its exhaust emissions.

Photochemical smog had been a growing problem in major urban areas for years, particularly in areas like Los Angeles, which are prone to atmospheric inversion layers. In the early fifties, scientific studies had linked smog to unburned hydrocarbons (HC) and nitrogen oxide (NOx) emissions from factories and motor vehicles. The state of California established the first limits on automotive emissions in 1959, followed in 1963 by the state of New York. In 1964, the U.S. Congress gave the federal government authority to regulate air pollution at a national level. The trend was not limited to the United States. Large Japanese cities had smog problems as well and there had been debate in the Japanese National Diet throughout the decade about the possibility of automotive emissions standards.

In December 1970, the United States enacted the Clean Air Act (sometimes known as the Muskie Act, after Sen. Edmund Muskie, D-Maine), which defined stringent national limits for automotive carbon monoxide (CO), HC, and NOx emissions, slated to take effect in 1975. (California had already implemented its own standards for NOx emissions, which took effect in 1971.) In response, Japan’s Environmental Agency proposed comparable regulations for Japanese vehicles along with a phase-out of leaded gasoline.

1971 Mazda R100 coupe front
For 1971, Mazda’s fledgling U.S. operation switched to the new SAE net rating system, dropping the R100’s nominal output to 77 hp (57 kW) and 80 lb-ft (109 N-m) of torque. Like all North American Mazda rotaries, the R100 now had a thermal reactor to control hydrocarbon emissions. Federalized cars also received round headlights, as the rectangular units used in other markets were not legal in the U.S. (author photo)

In both countries, the new standards triggered a political firestorm. Many automakers insisted that meeting the proposed standards was technologically impossible, particularly the new NOx limits. CO and HC emissions could be controlled by improving combustion efficiency or with add-on equipment like air injection, but NOx was a more difficult proposition, in part because some measures that reduced HC and CO (such as running very lean mixtures) actually increased nitrogen oxide emissions.

It was in this area that the rotary engine showed new promise. As a side effect of its combustion chamber shape, high surface-to-volume ratio, and relative low thermal efficiency, the rotary had greater HC emissions than did a comparable piston engine, but those same factors contributed to much lower NOx levels. (Nitrogen oxide emissions depend in large part on combustion temperatures, which are generally lower in a rotary than in a comparable reciprocating engine.) In fact, the Mazda rotaries were among the very few engines manufactured in 1970 that could meet the 1975 NOx standards without modifications. The rotary’s hydrocarbon emissions, meanwhile, could be brought under control with the use of a thermal reactor, which injected air into the exhaust stream to complete the combustion process. Toyo Kogyo had already developed that technology, which was included on all U.S.-bound rotaries.

1971 Mazda R100 coupe rear 3q
The Mazda R100 coupe is relatively low, standing only 53 inches (1,345 mm) high, but has a narrow tread width — 47.3 inches (1,200 mm) in front, 46.9 inches (1,190 mm) in back — which combined with narrow wheels and rather soft suspension settings to limit its maximum cornering grip. U.S. cars got larger 145SR14 radial tires on 14-inch (356 mm) wheels compared to the 13-inch (330 mm) wheels and 6.15 x 13 bias-plies on Japanese cars, but aftermarket wheels and rubber were commonly substituted. (author photo)

As a result, Toyo Kogyo was one of only a handful of auto manufacturers in the U.S. or Japan to admit that meeting the proposed NOx standards would indeed be feasible; company spokespeople told the press that Mazda would have an all-rotary U.S. lineup by 1975. By 1971, automakers like Ford would by knocking on Toyo Kogyo’s door, hoping to buy rotary engines for their own products. Almost overnight, the rotary — and by extension, Mazda — had gone from interesting oddball to possible savior of the auto industry.

That shift of fortune was a vindication for Tsuneji Matsuda, who had fought for the rotary through all its technical hurdles despite considerable skepticism both inside and outside the company. Sadly, Matsuda died in November 1970 and the presidency of the company passed to his son, 48-year-old Kouhei Matsuda, previously Toyo Kogyo’s executive vice president. Over the coming decade, Kenichi Yamamoto would take up his former boss’s banner as the Mazda rotary’s principal champion.

In part two of our story, we’ll look at Mazda’s subsequent rotary models — including the Capella/RX-2, Savanna/RX-3, Luce AP/RX-4, Cosmo/RX-5, and the unusual Mazda Rotary Engine Pickup — and chart Toyo Kogyo’s spectacular rise and fall in the mid-1970s.

# # #

ACKNOWLEDGMENTS

The author would like to thank Jens Krämer for the use of his photos; Halie Schmidt of Hill & Knowlton, Mazda’s PR agency, for her assistance in obtaining images and information from Mazda’s archives (some of which were provided on a nifty flash drive shaped like a trochoidal rotor); and Bob Nichols for the generous loan of his camera at the show where many of the photos for this article were taken.

The title of this article was inspired by the tagline of a mid-nineties U.S.-market Mazda ad, although the original ad was for the Miata, not a rotary-engined car.

For the record, the author has never owned a Mazda rotary, but does own a Mazda3 sedan, and years ago was compensated by a marketing firm hired by Mazda for participating in a couple of owner focus groups related to that model.


NOTES ON SOURCES

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Rx2… Capella 616” (no date, home.alphalink.com. au/ ~hillsk/ capella1.htm, accessed 9 October 2011); Andrew Tobias, “The Mazda Drives East,” New York Vol. 5, No. 48 (27 November 1972), pp. 66-69; Charles Trieu, “1973 Mazda RX 3 – Rotary Experiment,” Super Street February 2010, www.superstreetonline. com, accessed 10 October 2011; Mark Warner, Street Rotary: How to Build Maximum Horsepower & Reliability into Mazdas (New York: HPBooks, 2009); Larry Webster, “How It Works: The Mazda Rotary Engine (With Video!)” Popular Mechanics September 2011, www.popularmechanics. com/ cars/ news/ fuel-economy/ how-it-works-the-mazda-rotary-engine- with-video, accessed 7 October 2011; J. Patrick Wright, On a Clear Day You Can See General Motors: John Z. DeLorean’s Look Inside the Automotive Giant (Chicago, IL: Avon Books, 1980); Wally Wyss, “Mazda Wankel vs. Comet 302,” Motor Trend Vol. 23, No. 5 (May 1971), pp. 76-78, 87; and an email to the author from Ben Hsu of Japanese Performance Cars, 28 October 2011.

Additional information on Mazda’s rotary competition efforts came from “Bathurst 1971: Hardie-Ferodo 500,” “Bathurst 1972: Hardie-Ferodo 500,” “Bathurst 1973: Hardie-Ferodo 1000,” “Bathurst 1974: Hardie-Ferodo 1000,” “Bathurst 1975: Hardie-Ferodo 1000,” and “Bathurst 1976: Hardie-Ferodo 1000” (no date, Unique Cars and Parts, www.uniquecarsandparts. com.au, accessed 7 November 2011); Patrick Bedard, “Rotary Racer and Piston Politics,” Car and Driver Vol. 19, No. 10 (April 1974), pp. 58-74; Jim Donnelly, “Baby, It’s You: IMSA RS, the Ellis Island of Japanese-branded sedan racing,” Hemmings Sports & Exotic Car #56 (April 2010); “Former Hunterdon resident Walt Bohren, Mazda car racer for many years, drowns in British Virgin Islands,” Hunterdon County Democrat 10 February 2011, www.nj. com, accessed 13 October 2011; Michael J. Fuller, “An Interview with Jim Downing,” conducted 20 January 1996 (2000, www.mulsannescorner. com/ downing.htm, accessed 12 October 2011); Alexis Gosseau, “IMSA RS Challenge : everybody could go racing” (25 October 2009, IMSAblog, alex62.typepad. com/ imsablog/ 2009/ 10/ imsa-rs-challenge-everybody-could-go- racing.html, accessed 10 October 2011); Berny Herrera, “Rotary Power Shines at the 2006 SCCA Solo National Championships” (4 October 2006, RotaryNews.com, rotarynews. com/node/view/844, accessed 12 October 2011); Jeff Koch, “Le Mans-winning Mazda 787B to appear at the Japanese Classic Car Show” (24 August 2011, Hemmings Blog, blog.hemmings. com/index.php/2011/ 08/24/ le-mans-winning-mazda-787b-to-appear-at-the- japanese-classic-car-show/, accessed 13 October 2011); Aaron Robinson, “Checkered Past,” Car and Driver April 2007, www.caranddriver. com, accessed 15 October 2011; Chris Rosamond, “Epic Mazda 787B Rides Again: 700hp rotary racer to return for Le Mans demo” (23 May 2011, PistonHeads, www.pistonheads.com/news/default.asp?storyId=23665, accessed 13 October 2011); “Second Crop of Classes Halfway to a Solo National Championship” (27 September 2007, SCCA, 216.58.238.210/ newsarticle.aspx? hub=3&news=3163, accessed 12 October 2011); and Brock Yates, “The New Little Engine That Couldn’t,” Sports Illustrated 16 April 1973, pp. 79-81, sportsillustrated.cnn. com, accessed 19 October 2011.

Additional information on the environmental legislation of the 1970s and the 1973 OPEC embargo came from Chris Bishop, ed., The Encyclopedia of 20th Century Air Warfare (London: Amber Books/Barnes & Noble, 2004); California Environmental Protection Agency Air Resources Board, “Key Events in the History of Air Quality in California” (13 January 2011, ARB, www.arb.ca. gov/ html/brochure/ history.htm, accessed 18 October 2011); Anthony Curtis, “Is cleanliness three-cornered?” New Scientist and Science Journal Vol. 49, No. 740 (25 February 1971), pp. 415-417; Environmental Protection Agency, “Milestones” (9 July 2007, EPA, www.epa. gov/ oms/ invntory/ overview/solutions/ milestones.htm, accessed 10 October 2011); David Halberstam, The Reckoning (New York: William Morrow and Company, 1986); Michio Hashimoto, “History of Air Pollution Control in Japan,” How to Conquer Air Pollution: A Japanese Experience (Studies in Environmental Science 38), ed. Hajime Nishimura (Amsterdam: Elsevier Science Publishers B.V., 1989), pp. 1–90; David C. Isby, Jane’s Air War I: Fighter Combat in the Jet Age (New York: Collins Reference, 1997); National Traffic Safety and Environmental Laboratory, “Overview and Future Prospect of Emissions Regulations in Japan” (4 February 2003, NTSEL, www.ntsel. go.jp/e/ symposium/040203session4.pdf, accessed 10 October 2011); Donald Neff, Warriors Against Israel: How Israel Won the Battle to Become America’s Ally 1973 (Ft. Collins, CO: Linden Press, 1981); Hajime Nishimura and Masayoshi Sadakata, “Emission Control Technology,” How to Conquer Air Pollution: A Japanese Experience, pp. 115–115; the official website of the Organization of the Petroleum Exporting Countries, www.opec. org, accessed 14 November 2011; and the Wikipedia® entries on the 1973 oil crisis (en.wikipedia.org/wiki/1973_oil_crisis, accessed 13 October 2011) and the Yom Kippur War (en.wikipedia.org/wiki/Yom_Kippur_War, accessed 14 November 2011).

Additional information came from the Auto Editors of Consumer Guide, “1963-1966 NSU Wankel Spider” (24 July 2007, HowStuffWorks.com, www.howstuffworks. com/ 1963-1966-nsu-wankel-spider.htm, accessed 7 October 2011); International Money Fund, “Cooperation and reconstruction (1944–1971)” and “The end of the Bretton Woods System (1972–1981),” About the IMF: History, N.d., www.imf.org/external/about/history.htm, last accessed 2 April 2014; Jim Kaler, “Capella” (13 December 1998, University of Illinois Department of Astronomy, stars.astro. illinois.edu/ sow/ capella.html, accessed 13 October 2011); “Kohei Matsuda, Former President of Mazda,” New York Times 4 August 2002, www.nytimes. com, accessed 14 November 2011; Jona Lendering, “Ahuramazda and Zoroastrianism” (no date, www.livius. org/ ag-ai/ ahuramazda/ ahuramazda.html, accessed 13 October 2011); “NSU Wankel Spider” (2008, NSU Prinz, www.nsuprinz. com/ Models /NSU_Spider.asp, accessed 7 October 2011); Masaaki Sato, The Honda Myth: The Genius and His Wake (New York: Vertical, Inc., 2006), and The Toyota Leaders: An Executive Guide, trans. Justin Bonsey (New York: Vertical, Inc., 2008); “Showroom Stock Sedans: The Nine Cars on the Track,” Car and Driver Vol. 17, No. 11 (May 1972), pp. 38-45; Eiji Toyoda, Toyota: Fifty Years in Motion (Tokyo: Kodansha International, 1987); the Wikipedia entries on the Bretton Woods system (en.wikipedia.org/wiki/Bretton_Woods_system, accessed 1 November 2011), Jim Downing (en.wikipedia.org/wiki/Jim_Downing, accessed 12 October 2011), Jujiro Matsuda (en.wikipedia.org/wiki/Jujiro_Matsuda, accessed 13 October 2011), the Mazda Capella (en.wikipedia.org/wiki/Mazda_Capella, accessed 28 October 2011), Mazda Cosmo (en.wikipedia.org/wiki/Mazda_Cosmo, accessed 16 October 2011), the Mazda Familia (en.wikipedia.org/wiki/Mazda_Familia, accessed 26 October 2011), Mazda Grand Familia (en.wikipedia.org/wiki/Mazda_Grand_Familia, accessed 3 November 2011), the Mazda Luce, en.wikipedia.org/wiki/Mazda_Luce, accessed 16 October 2011, the Mazda R100 (en.wikipedia.org/wiki/Mazda_R100, accessed 7 October 2011), the Mazda RX-2 (en.wikipedia.org/wiki/Mazda_RX-2, accessed 9 October 2011), the Mazda RX-3 (en.wikipedia.org/wiki/Mazda_RX-3, accessed 10 October 2011), NSU Motorenwerke (en.wikipedia.org/wiki/NSU_Motorenwerke, accessed 7 October 2011), the NS Savvanah (en.wikipedia.org/wiki/NS_Savannah, accessed 13 October 2011); The Return of Ultraman (en.wikipedia.org/wiki/The_Return_of_Ultraman, accessed 9 October 2011), and the SS Savannah (en.wikipedia.org/wiki/SS_Savannah, accessed 13 October 2011).

Some historical exchange rate data for the dollar and yen came from Lawrence H. Officer, “Exchange Rates Between the United States Dollar and Forty-one Currencies” (2011, MeasuringWorth, http://www.measuringworth.org/exchangeglobal/, used with permission). Exchange rate values cited in the text represent the approximate equivalency of Japanese and U.S. currency at the time, not the contemporary U.S. suggested retail prices, which are cited separately. Please note that all exchange rate equivalencies cited in the text are approximate; this is an automotive history, not a treatise on currency trading or the value of money, and nothing in this article should be taken as financial advice of any kind!


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21 Comments

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  1. I’ve always loved Mazda’s rotary cars. Fantastic article, and I can’t wait for part 2…

  2. Great story looking forward to part 2. A friend in Tasmania had several of those bertone Luces nice cars the later models had the 1800 Capella engine.

  3. Thanks for the Mazda rotary article. I’m looking forward to reading Part 2. Despite growing up around Mazda rotary-powered cars, I learned quite a bit!

  4. It’s a real shame that no one can seem to lick the engine’s fuel and oil consumption problems. I have heard some discussion of Mazda using rotaries in hybrids, which makes some sense to me. Rotaries are so small and, on paper at least, elegantly designed.

    Man, that Luce coupe is a looker.

    1. I don’t know about hybrids, but Mazda has done quite a bit of development on a hydrogen-fueled rotary, which has been offered on a limited basis for fleet sales in some markets.

      If the next-generation 16X engine materializes, Mazda is hoping to reduce fuel consumption substantially, in part by adopting direct injection. Still, since piston engines keep improving in that regard, as well, I don’t know that the rotary will ever match the reciprocating engine in specific fuel consumption. Some things can be mitigated (like wall quench), but other factors, like the combustion chamber surface area to volume ratio, are sort of the nature of the beast.

      The Luce R130 is indeed a very nice-looking car. I’d never seen one before I started researching this story.

  5. Very interesting article, well, as usual, Aaron!
    The topic was somewhat forgotten in France after Citroën heavily invested in the technology, eventually failed to make it work and had to drop the project in the early 70’s. They had been so serious about it that the models developed in the late 60’s, the GS and the XM, were designed for a rotary. They had to hastily develop a reciprocating engine for the GS and make it fit in the engine bay that was not large enough.
    The XM eventually was painfully fitted with a Peugeot engine.
    Anyway Citroën was never able to design a good engine. This huge investment and its failure played an important role in the demise of the company.

    Nick

    1. “They had been so serious about it that the models developed in the late 60’s, the GS and the XM, were designed for a rotary.”
      You mean the SM, don’t you?

      1. I believe Nicolas was probably referring to the CX, which replaced the Citroën DS in 1974. I’ve never heard anything about the SM being intended for rotary power — of course the production cars had the Maserati V6 — but I think the CX was. The XM was the CX’s eventual successor, introduced in the late eighties.

  6. Right Aaron, my pen slipped, it was the CX.
    The XM was its successor.
    The SM, stangely enough, was fitted with the (in)famous Maserati V6 even though Citroën had such a faith in the future of the rotary as the ultimate replacement of the reciprocating.

    Nick

    1. Timing may have had something to do with it. Citroën didn’t build the first M35 single-rotor cars until the fall of 1969, and as I understand it, they were essentially evaluation models, not yet intended for large-scale production. The BiRotor wasn’t introduced until 1974, about four years after the SM debuted. Even if Citroën were keen to give the SM rotary power, it probably wouldn’t have been ready until a few years after launch, even in a best-case scenario.

      If things had worked out differently, I imagine Citroën might have added a rotary engine to the SM later, perhaps in a second-generation version for the mid-seventies. Of course, even if the Comotor engines had been more successful, the SM was not, and might have been dropped without ever getting a rotary engine.

  7. For them the rotary was the future type of engine for all applications, just as well as they were persuaded they had a market for the SM.
    With NSU, Mazda and others working on it it’s understandable.
    Your article is very interesting by showing how Mazda made a success of it, or at least could partly make a living with it, well… that’s a success, isn’t it?
    Strangely enough it didn’t catch on as an aviation engine either.
    Nick

  8. [quote=Administrator] Citroën didn’t build the first M35 single-rotor cars until the fall of 1969, and as I understand it, they were essentially evaluation models, not yet intended for large-scale production. The BiRotor wasn’t introduced until 1974, about four years after the SM debuted.[/quote]
    Starting in 69 a limited number M35, and in 73 GS Birotor, were sold to selected, faithful (and masochist) clients but the engine proved such a burden to maintain that Citroën offered to buy them back and scraped them. A few people only turned down the offer. The maintenance contracts were canceled for them. The few models still in existence are now very expensive collectors’ items, the day dream of all the GS enthusiasts.
    So there was actually a future for the rotary! ;-) As usual the car that nobody wanted became the car that nobody can afford.

    Nick

    1. The source I was looking at (John Hege’s [i]The Wankel Rotary Engine: A History[/i]) suggests that Citroën had basically intended to buy back the early evaluation engines from the outset, which would make a lot of sense.

      I don’t know about France, but in the U.S., automakers are legally obligated to provide parts support for production models for a specific period of time, typically 15 years — obviously not an appealing prospect for cars or engines that don’t end up in mass production! For that and other reasons, some automakers have tended to offer such evaluation vehicles only as a closed-end lease or other type of loan-out, with no option to actually purchase and keep the vehicle at the end; I assume that not actually selling it avoids triggering certain legal requirements.

  9. The Europeans have basically the same obligations as the Americans. As far as I understood, the deal was under specific conditions and since Citroën offered to buy them back it could cancel any support for those who rejecter the offer. It’s stupid it didn’t keep one example for history.

    Mazda is the only one who succeeded with a rotary over the years while all the others flopped.
    Well done!
    Nick

  10. This is an interesting article as usual, I’m waiting for the second part. While you’re at it, how about an article covering GM’s attempt to build a rotary engine?

    1. I thought about it, but in researching this article, I’m finding that detailed information about its development seems to be surprisingly scarce. While the development of the NSU, Mazda, and Curtiss-Wright engines is pretty well-documented, GM played it very close to the vest. To really do it justice would probably require talking to some of the engineers who worked on it, assuming that the people involved are still living, and willing (and able) to talk about the program.

  11. No need to mourn it’s passing. A technological dead end. I don’t miss the
    ffffttttt exhaust “note” of them at all.
    Used to be a few about Brisbane, Delighted to see and hear that rust and enlightenment of the owners has made them almost extinct.

    Good riddence. So it could rev to 5 digits.
    BFD.

  12. Wow, FANTASTIC article! Thanks for the great piece on Mazda, the detail and depths you go to are above and beyond. One of the best history-of-automaker stories that I’ve read. Thanks again!

  13. Another great article Aaron. Really appreciating your narrative drive and level of scholarship. I’m starting to believe the R100/1200 body was designed by Bertone as well, but can’t verify. Do you know of any text that addresses the connections between the Italian design houses and the Japanese manufacturers in depth?

    1. I so far haven’t found anything to suggest one way or another whether the first-generation Familia was done by Bertone, although it’s certainly plausible given that Bertone did the first Luce and the Luce Rotary Coupé in that period. Even if Stilo Bertone didn’t do the Familia or the first Capella, those designs have a definite Italian flavor, much more so than subsequent products of Toyo Kogyo’s in-house design studio, which feel more typically mid-seventies Japanese.

  14. I really like that little sidebar referring how to calculate the Wankel’s full displacement. I know Japan has different regulations than the U.S. and that Mazda had no choice to only count one chamber for each rotor (Geometric Displacement) due to extra taxes being placed on “bigger” cars. Either way, I really hope Mazda brings their Wankel rotaries back to the streets, because that awesome RX-Vision concept needs to be on the roads

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