É um texto muito grande, mas digno de se ler
Mazda Cosmo SportThe story of vision, dedication and loyalty behind Mazda's svelte 2-seat sports car and its engine
By Sam Mitani • Photos By Koichi Ohtani 
SHIMIZU, Japan — Many of you may not recognize the car shown here at first glance — understandable, considering the Mazda Cosmo Sport was never marketed in the U.S. So why is it being featured in the pages of this magazine? Well, one reason is that it's a nimble, lightweight sports car, the kind we like here at R&T.
But the main reason is to tell the story behind the car's powerplant, Mazda's first production rotary engine. To get a full appreciation of cars such as the Cosmo Sport and especially the RX-7 and RX-8, one must turn back the pages to when Mazda was still known as Toyo Kogyo, perhaps even as far back as to the day the atomic bomb was dropped on the quiet city of Hiroshima.
Hours after that fateful evening of August 6, 1945, Toyo Kogyo, a manufacturer of 3-wheeled industrial vehicles, converted its facilities into a makeshift hospital and a gathering place for those looking for loved ones. And despite losing more than 200 employees to the blast, the company was able to resume business after only three months. Not long after, an up-and-coming engineer named Kenichi Yamamoto, who returned to Hiroshima from Tokyo to look for his family (he lost his sister and father in the bombing), joined the company
The following years at Toyo Kogyo — as well as the city — were concentrated on rebuilding. In the meantime, two companies to the north, Nissan and Toyota, began producing and marketing automobiles on a never-before-seen scale. Their impact on the domestic business sector was so significant that the Japanese government wanted to limit the number of primary automobile makers to no more than three. Toyo Kogyo's president, Tsuneji Matsuda, a proud but shrewd man who would rather have died than see his company become a subsidiary of another, set his sights on becoming the third of Japan's Big Three. And to do so, he needed a passenger car. He assigned Yamamoto, then 36 years old, to head the development of a "4-wheel" automobile.
The result was the Mazda R360 Coupe, a diminutive 4-seater that emphasized value. It proved a winner at the dealerships, selling a few thousand units. But despite its success, Toyo Kogyo still faced the possibility of being bought out.
It was then that Matsuda received news of a new type of engine that had been "successfully" developed in Germany. Conceived by Felix Wankel and produced by NSU, this powerplant was reputed to be far superior to its piston counterpart — it was smaller and believed to be more durable and efficient. Matsuda immediately flew to Germany, believing that this new technology was destined to save his company. And despite knowing the engine had not yet been perfected, Matsuda in 1961 acquired the rights to produce and further develop the Wankel, paying an exorbitant amount of licensing money to the German company.
Once the ink dried on the document, he turned to his able confidant, Yamamoto, to oversee the development of this engine, which was to be placed into a new line of passenger cars. Yamamoto enthusiastically accepted the assignment, but little did he know then that he was embarking upon the challenge of his life.
"Mr. Rotary" Kenichi Yamamoto
He tested a prototype powerplant immediately. Once he loaded it into a mule, he was horrified to discover that the "revolutionary" Wankel engine was not what it was reputed to be. It wasn't even close to being viable for production, with problems far greater than he had imagined.
The storage rooms at Toyo Kogyo began to overflow with failed prototypes. Some of the other manufacturers also working on the rotary engine gave up, publicly stating that developing it into a viable automotive powerplant was impossible.
It seemed that Matsuda's gamble had backfired. Yamamoto, sensing the hopelessness of the situation after hundreds of failed efforts, decided to throw in the towel. He visited the president's office for what he thought would be the last time. "I'm sorry but I don't have what it takes to fulfill this assignment," he told Matsuda.
Expecting the volatile Matsuda to explode with rage, Yamamoto found the president to be unusually calm. Matsuda turned to his dejected engineer, looked him in the eye and said in a low compassionate voice: "There's only one person in this world who can make this rotary work, and that's you. You, who call this city home. You, who love this city more than anything else in the world."
Built on the Miata platform, powered by the Renesis rotary, Mazda’s Cosmo 21 may get the green light for production next year. Volume will be limited, and the price will be somewhere near $50,000.Matsuda, who incidentally lost his brother to the bomb, was putting the fate of his company into the hands of another, something no one could have ever imagined him doing. With that, Yamamoto promised to give it one more go. He handpicked the best engineers in the company to form a team. They became known as "
the 47 rotary warriors." Yamamoto rallied his troops by saying, "This is our chance to show the world what we Hiroshimans are made of." He asked them to sacrifice everything for the cause.
At about this time, added inspiration was provided by the first glimpse of the car that the engine was to go into. It wasn't a boxy sedan that most of them expected, but a sleek, svelte sports car with flowing lines.
After a few months, the engineers were able to stop the oil leak by using a rubber seal on the rotor. It was never tried before because it was believed that the rubber would melt from the engine heat, but the temperature on the rotor itself turned out to be much lower than expected. Now all that remained were the devil's fingernail marks. And the devil was a worthy foe indeed. Yamamoto had tried more than 500 different metals and combinations of metals to form the apex seals, but none proved effective — they were either too coarse, scratching the inner engine wall, or too soft, prohibiting the rotor from spinning effectively. Then, one day, Yamamoto happened to fix his gaze upon his pencil. He realized immediately that he held in his hands exactly what he was looking for. The carbon graphite in pencil lead was resistant to scratching and its surface was unusually slick. All he needed to do was make the material hard enough to stand the rigors of a spinning rotor.
He asked his chief metallurgist, Jun Miyata, to try to produce an appropriate material. Miyata mixed the carbon with all sorts of hard metals but couldn't get the desired results. Then, purely as an experiment, he mixed the carbon with a soft metal: aluminum. To his surprise, the aluminum-impregnated carbon proved to be the winning formula.
The new formula was immediately tested. Yamamoto and his crew placed the engine on the test bed. No marks. Then they plopped it into a mule and took it to the test track where it ran and ran and ran. Finally after about 70,000 miles, they brought the car in and disassembled the engine. They inspected the bore lining; the fingernail marks were nowhere to be found.
The arduous ordeal was over. After more than five years, Yamamoto and his team had finally achieved their goal. And the rotary engine was ready for production.
In total, 1176 Cosmo Sports were produced, which included about 900 stretched-wheelbase versions. The car you see on the previous pages, number 11321, is among the last to come down the line. It has been carefully maintained by Yasunobu Mochizuki, the president of the Cosmo Owners Club.
The car is a delight to drive with a light, nimble nature that's similar to that of the Miata. The engine resonates with a unique hum, a sound that could come only from a rotary. The two-rotor powerplant, dubbed the 10A, began life producing 110 bhp, but later ones, including his 1972 model, pumped out 128 bhp at 7000 rpm and 103 lb.-ft. of torque at 5000. This enabled the 2110-lb. car to run to 60 mph in roughly 7.5 seconds (quicker than today's Miata!) and to the quarter-mile mark in roughly 15.5.
Despite possessing such wonderful performance, the rotary engine did not receive its fair share of praise. Thus, a new challenge faced Yamamoto; he needed to somehow convince the public that his Wankel was as good or even better than its piston counterpart.
He turned to Hiroshi Yamamoto (no relation) to look for an appropriate venue. The young Mazda race specialist found one. It was an event called the Marathon de la Route, an endurance race that started and finished in Liege, Belgium, driving through mountain roads to the famed Nürburgring, where the cars would race for 84 hours straight. At the start of the race, no one even gave the little Japanese sports car a second look. Things would change.
Two Cosmo Sports were entered. One experienced non-engine-related problems during the 82nd hour at the Nürburgring and had to be withdrawn. But the other cruised around the famed circuit effortlessly. During the ride back to Liege, Belgians crowded the streets, pulling for the little Japanese car to win the race. The Mazda didn't win, but it did finish in 4th place behind a couple of Porsche 911s and a Lancia Fulvia, a result that exceeded everyone's expectations.
Fast forward 23 years, to 1991. A rotary-powered Mazda claims the checkered flag of the world's most prestigious endurance race — the 24 Hours of Le Mans. With this win, the Mazda 787B became the only rotary-powered car to ever win the event. And while other Japanese car companies, ones that nearly consumed Mazda a few decades before, have tried to conquer the famed French circuit on numerous occasions, the little Hiroshima-based carmaker still stands as the only one to do so. Overseeing this victorious effort was Takaharu Kobayakawa, one of the engineers who worked on the original Cosmo Sport rotary. Indeed, the heritage of the 787B's Le Mans win can be traced directly back to the days of the rotary engine's infant stages, perhaps even as far back as that fateful day in 1945.
Who could have predicted then that from the rubble of this tragedy a world champion would triumphantly emerge.
1972 Cosmo Sport Specifications Curb weight 2110 lb.
Wheelbase 92.5 in.
Length 162.6 in.
Width 62.6 in.
Height 45.9 in.
Engine & Drivetrain
Engine 2-rotor Wankel
Displacement 982 ccCompression ratio 9.4:1
Horsepower 128 bhp @ 7000 rpm
Torque 103 lb-ft @ 5000 rpm
Transmission 5-speed manual
Chassis & Body
Layout front engine/rear drive
Brakes, f/r discs/drums
Wheels steel, 15 in.
Steering type rack & pinion
Suspension, f/r upper & lower A-arms, coil springs, tube shocks/De Dion, leaf springs, tube shocks
Edited by: Rviper 
at: 5/13/03 11:31:14 pm
