Last year, Mazda celebrated forty years of rotary-engine zoom. We ate cake, fantasized that a new rotary might soon resuscitate the RX-7, and then began compiling these cool facts related to Felix Wankel's wonder motor.
Herr Wankel (1902-88) endured major hardship. His father was a World War I casualty. Poverty denied him an apprenticeship and a university education. During his twenties, he was a member of the Hitler Youth. The Nazis imprisoned Wankel in the 1930s, and the French locked him up again in 1945.
Throughout his life, Wankel never held a driver's license. Munich's technical university presented him with an honorary doctorate degree in 1969.
At seventeen, Wankel dreamed that he drove a car he had constructed to a concert. To friends in the dream, he bragged, "My car has a new type of engine, half turbine, half reciprocating. It's my invention!"
Five years later, Wankel opened a shop in Heidelberg to commence work on his dream machine. His first patent was issued in 1929. Before and during WWII, Wankel worked on rotary valves and seals for aircraft engine makers, including BMW and Daimler-Benz.
Wankel's experimental engine ran in 1957, producing 21 hp. Both the rotor and its housing rotated in this early design.
Wankel's rotary engine is the only internal-combustion engine invented in the twentieth century to achieve production status.
Mazda president Tsuneji Matsuda signed a study contract with Wankel's development partner, NSU, in 1961. Mazda's first experimental rotary engine fired up later that year.
Kenichi Yamamoto became chief of Mazda's rotary research department in 1963. After problems with apex seals were solved, experimental engines were capable of running 300 hours at high speed.
More than a dozen automotive, motorcycle, marine, and industrial manufacturers signed license agreements to develop rotary engines. Alfa Romeo, AMC, Citroën, Ford, GM, Mercedes-Benz, Nissan, Porsche, Rolls-Royce, Suzuki, and Toyota all joined the rotary club.
Mazda and NSU raced to produce the first rotary-powered automobile. NSU won with its $2979, 64-hp, single-rotor Spider two-seater introduced in 1964. Mazda countered with a display of two- and four-rotor engines at that year's Tokyo Motor Show.
Following the Cosmo Sport 110S's introduction at the 1966 Tokyo show, Mazda began selling its first rotary car the following year. Only 1176 two-rotor coupes were produced through 1972.
After NSU's two-rotor Ro80 luxury sedan bowed in 1967, owners traditionally saluted one another on the road with fingers raised showing how many times the apex seals in their engines had been replaced. NSU merged with Audi in 1969, and the Ro80's Wankel was shelved in '77.
The rotary engine's competition baptism came in 1968, when a Cosmo Sport finished fourth overall in the eighty-four-hour Marathon de la Route endurance race at the Nürburgring.
Rotary engines were attractive to some makers striving for exhaust-emissions compliance, because they produced lower NOx pollution than piston engines. Poor thermal efficiency and sealing challenges ultimately thwarted the engine's popularity.
Rotaries are simpler, lighter, and more compact than piston engines of comparable power. Unlike reciprocating engines, their moving parts are in perfect balance. Since no valve train components are present, friction is substantially lower.
While there are only three major moving components - two rotors, one eccentric shaft - in a Mazda rotary engine, nearly 100 seal-related parts are also required.
Each rotor forms three working chambers inside the figure-eight-shaped trochoid housing. Rotors turn one-third as fast as the eccentric shaft that takes power out of the engine. As a result, each chamber delivers torque over 270 of the 1080 degrees required to complete the combustion process, versus 180 out of 720 degrees for a piston engine. This long-duration torque delivery underlies the rotary's smooth operation.
The first racing victory for a rotary engine on American soil occurred in 1973, when Patrick Bedard, an editor at Ann Arbor's other car magazine, drove a Mazda RX-2 to a noisy win at a Lime Rock IMSA RS event.
In 1974, a Mazda RX-3 set a 160-mph Bonneville record. Three subsequent records, topped off by a 242-mph two-way average in 1995, were set by one normally aspirated and two turbocharged Mazda RX-7s.
The California rotary-engine-tuning emporium, Racing Beat, was founded in 1971 by engineer Jim Mederer and business manager Ryusuke Oku. Racing Beat constructed all the engines and three of the race cars cited in items 18 and 19. Mederer built the 930-hp, twin-turbo rotary for the RX-7 he drove to the C-Blown Modified Sports land-speed record at Bonneville in 1995.