Rotary engine inventor Felix Wankel born - Aug 13, 1902 - HISTORY.com Rotary engine inventor Felix Wankel born Share this: Rotary engine inventor Felix Wankel born Author Rotary engine inventor Felix Wankel born URL Publisher A+E Networks The German engineer Felix Wankel, inventor of a rotary engine that will be used in race cars, is born on August 13, 1902, in Lahr, Germany. Wankel reportedly came up with the basic idea for a new type of internal combustion gasoline engine when he was only 17 years old. In 1924, Wankel set up a small laboratory where he began the research and development of his dream engine, which would be able to attain intake, compression, combustion and exhaust, all while rotating. He brought his knowledge of rotary valves to his work with the German Aeronautical Research Establishment during World War II, and to a leading German motorcycle company, NSU Motorenwerk AG, beginning in 1951. Wankel completed his first design of a rotary-piston engine in 1954, and the first unit was tested in 1957.

In other internal-combustion engines, moving pistons did the work of getting the combustion process started; in the Wankel rotary engine, an orbiting rotor in the shape of a curved equilateral triangle served this purpose. Fewer moving parts created a smoothly performing engine that was lightweight, compact, low-cost and required fewer repairs. After NSU officially announced the completion of the Wankel rotary engine in late 1959, some 100 companies around the world rushed to propose partnerships that would get the engine inside their products. Mazda, the Japanese automaker, signed a formal contract with NSU in July 1961, after receiving approval from the Japanese government. In an attempt to experiment with the rotary engine and perfect it for use in its vehicles, Mazda formed an RE (Rotary Engine) Research Department in 1963. The Cosmo Sport, which Mazda released in May 1967, was the planet’s first dual-rotor rotary engine car. With futuristic styling and superior performance, the Cosmo wowed car enthusiasts worldwide. Mazda began installing rotary engines in its sedans and coupes in 1968, and the vehicles hit the U.S.

market in 1971. In the wake of a global oil crisis in 1973-74, Mazda continually worked on improving its rotary engines to improve fuel efficiency, and by the end of that decade its sports cars had become popular in both Europe and the United States In addition to Mazda, a number of other companies licensed the Wankel engine during the 1960s and 1970s, including Daimler-Benz, Alfa Romeo, Rolls Royce, Porsche, General Motors, Suzuki and Toyota. Meanwhile, Wankel continued his own work with the rotary piston engine, forming his own research establishment in Lindau, Germany, in the mid-1970s. In 1986, he sold the institute for 100 million Deutschmarks (around $41 million) to Daimler Benz, maker of the Mercedes. Wankel filed a new patent as late as 1987; the following year, he died after a long illness. Related Videos What type of engine did Felix Wankel invent? What type of engine did Felix Wankel invent?

+1 vote posted Oct 9, 2015 by Rajni Share this question Your comment on this question: Email me at this address if a comment is added after mine:Email me if a comment is added after mine Privacy: Your email address will only be used for sending these notifications. Anti-spam verification: To avoid this verification in future, please log in or register . 2 Answers +1 vote During World War II, Wankel developed seals and rotary valves for German air force aircraft and navy torpedoes, for BMW and Daimler-Benz. He conceived the Wankel engine in 1924 and won his first patent in 1929. answer Oct 10, 2015 by Amit Kumar Pandey Your comment on this answer: Email me at this address if a comment is added after mine:Email me if a comment is added after mine Privacy: Your email address will only be used for sending these notifications. Anti-spam verification: To avoid this verification in future, please log in or register .

0 votes Felix Heinrich Wankel (13 August 1902 – 9 October 1988) was a German mechanical engineer and inventor after whom the Wankel engine was named. answer May 18 by Kapil Kumar Your comment on this answer: Email me at this address if a comment is added after mine:Email me if a comment is added after mine Privacy: Your email address will only be used for sending these notifications. Anti-spam verification: Felix Wankel, Inventor, Is Dead - Creator of Rotary Engine Was 86 - NYTimes.com Felix Wankel, Inventor, Is Dead; Creator of Rotary Engine Was 86 By GLENN FOWLER Published: October 14, 1988 Felix Wankel, the inventor of the rotary engine for automobiles that bears his name and of other automotive and aeronautical equipment, died Sunday at his home in Lindau, West Germany, on Lake Constance. He was 86 years old. A research engineer who was known as a brilliant mathematician with a mechanical bent, he never received a university education.

His crowning achievement, the Wankel rotary piston engine, was developed over many years between the two World Wars in a private experimental shop that Mr. Wankel had set up while he was selling scientific books for a living. The revolutionary engine did not became a dominant factor in automobile production, but it found a small but secure niche, notably in the Mazda motor cars produced in Japan. The engine has two moving parts, a triangular rotor and a single elliptical chamber. The big difference between Mr. Wankel's engine and the conventional internal combustion engine is that the Wankel has no piston and no cylinders. It is designed to generate more power in less space than conventional engines. Auto Companies Unenthusiastic Designing the Wankel engine was far less difficult than getting it manufactured because help from an experienced automotive company was necessary. Like countless other inventors with ideas both brilliant and bizarre, he elicited little enthusiasm among major manufacturers in his native Germany. It was not until the late 1950's that he finally got an audience and financial support from the N.S.U. Werke Motor Company, a small but progressive manufacturer in West Germany whose initials stand for ''Sewing Machine Union of Neckarsulm.'' Mr.

Wankel developed a satisfactory prototype, but it was not until a decade later that he was able to get the engine into production for Mazda cars in Japan. The Wankel-engine Mazda was introduced in the United States in 1971. In the first decade, Mazda sold 200,000 rotary-engine cars in the United States, priced at up to $12,000. The RX-7 rotary line is still offered here by Mazda, with current prices ranging from $24,000 to $30,000. Mr. Wankel was born in 1902 in Lahr in the Black Forest; his father was a forest ranger. The family was not prosperous, and Felix was forced to go to work before finishing secondary school. He later recalled that, from his youth, he had a single gift: technical drawing. He never learned to drive a car; ''I was always too dreamy, and my eyesight was too poor for a driver's license.'' But he tinkered with automotive machinery whenever he could find the time, finally acquiring enough money selling books for a Heidelberg publishing house to set up the shop where he developed the rotary engine.

A Start on Motorcycles By 1926, Mr. Wankel was able to concentrate on engineering full-time. His goal was the rotary automobile engine, but he started by experimenting with rotary valves on motorcycle engines. He applied for patents on his rotary concept in 1933. He had been an early follower of Hitler but quit the Nazi party in 1932. Before he got the patents, he was arrested for what he said were his attempts to uncover corruption in the party. His release was effected by Hans Nibel, technical director of Daimler-Benz, makers of Mercedes-Benz automobiles. Mr. Nibel gave Mr. Wankel a job doing research on sealing components, rotary valves and rotary engines. A year later he and went to the rival Bavarian Motor Works. In 1936 the German Air Ministry invited Mr. Wankel to continue his research in a government aviation institute. Always at odds with the authorities, he refused, but finally went to work for the German Government when Hermann Goring agreed to have a separate institute, the Wankel Test Institute, set up just for him. There Mr.

Wankel devised a system for cooling the pistons of an aircraft engine, and later in conjunction with Mercedes-Benz developed a rotary valve for aircraft engines that was widely used in World War II. Imprisoned at War's End At the war's end he was imprisoned by the French occupation forces for a year and his workshop was dismantled as part of the Allied effort to prevent the defeated Germans from engaging in research work. After his release he settled in Lindau, where he continued the experiments that culminated in the successful Wankel engine. He never joined N.S.U., but was a member of a separate corporation known as Wankel-N.S.U., which held the patients and arranged licenses for production. Mr. Wankel remained vigorous throughout his life. Among his hobbies were rowing and running, and he maintained a prodigious work schedule, often staying at his research facility on Lake Constance until the early morning. Mr. Wankel's wife died in 1978. They had no children.

Photo of Felix Wankel (1972) The Inventor Of The Rotary Engine Was A Nazi Nutjob The Ten Craziest Automotive Pioneers Of All Time The Ten Craziest Automotive Pioneers Of All Time The Ten Craziest Automotive Pioneers Of All Time Spaceships, flying cars, and rocket boosters: these are the craziest designers in the history of… Read more Read more Felix Wankel was a great inventor, having invented the rotary engine with no university diploma on his resume, just experience from working in a book shop. In the 1960s, it seemed like the Wankel engine was going to be then next great innovation in car design. Even GM bought into the hype. The engine ended up being too thirsty for the fuel-crisis '70s, and by the end of the decade only one carmaker stuck around with the rotary: Mazda. After earlier dreams of a full-rotary lineup, Mazda kept the engine going in its fantastic RX-line of sports cars, which ended up being the final cars to use rotaries .

The Last Mazda Wankel Engine Has Been Built The Last Mazda Wankel Engine Has Been Built The Last Mazda Wankel Engine Has Been Built Last Friday, June 22, 2012, the Wankel rotary engine's last remaining and steadfast devotee,… Read more Read more It's because of this orphan status, and because of the legacy of cars like the double-rotor 1990s RX-7, the triple-rotor Cosmo, and the wailing, Le Mans-winning, quad-rotor 787b that the Wankel engine, and its creator have a quasi-cult following. Some call them rotards . Advertisement Advertisement You could call Felix Wankel a bit cult-ish, too, but he was more interested in militarizing the Aryan race than restoring sports cars. Born in 1902 in the Baden state of Germany, Felix Wankel was an early supporter and member of the Nazi Party. He saw his first Nazi rally on a trip to Bavaria with his widowed mother in 1920, writes Marcus Popplow in Felix Wankel: more than an inventor's life.

You can read much of the book right here on Google Books, if you speak German. A comprehensive summary of his Nazi career starts on page 36. He was hardly 19 years old when he joined the 'German People's Protection and Defiance Federation' in 1922, the most active anti-Semitic group in Germany at the time, which is probably saying something. Only a year later he was a member of the official Nazi party, the NSDAP. Throughout the 1920s, Wankel regularly traveled in public wearing a swastika, and when he posed for pictures, it was often with one on, writes Popplow. Popplow also notes that Wankel often wrote anti-Semitic passages in his diary, though during interviews in the 1980s Wankel stated that these entries, along with anti-Semitic leaflets he distributed were only youthful mistakes. Sponsored In 1926, Wankel met with his regional leader of the Nazis, Robert Wagner and was appointed to run Baden's Hitler Youth. Wankel, however, fell out with Wagner, as Wankel wanted the Nazi party to be more militaristic.

Wankel was so displeased with Wagner's more political aspirations that he publicly accused Wagner of corruption in 1931. Wagner stripped Wankel of his title and then kicked him out of the Nazi Party. The Badische city archive gives a quote from Wagner, describing how much he hated Wankel. Advertisement Advertisement Wankel is a man of entirely one-sided intelligence, which produces only in the negative ... , thereby poisonous ... acts. Wankel didn't stop his accusations, and Wagner had him arrested in '33. Of course, this didn't stop Wankel, a charismatic speaker (as noted by the local Badische newspaper ) with good connections thanks to his technical presentations to top-ranking Nazis. Hitler's economic adviser got Wankel out of jail and Wankel formed his own splinter Nazi party in Baden. Wankel got himself a federally-appointed factory in Lindau in 1937, and though he was initially denied re-entry into the Nazi Party, Hitler's economic adviser intervened once more to make him an officer in the SS in 1940. In 1942, Wankel was kicked out by the Nazis once more, for unknown reasons.

After the war, the French imprisoned him for his Nazi ties. It's difficult to disassociate the man's Nazi side from his inventions, because his Nazi bent was particularly turned towards technology. Wankel even met with Himmler (you can see a photo of this meeting right here ) and also Hitler to discuss the importance of technology and technical education. Wankel's best connection to the Nazi party came from Hitler's aforementioned economic adviser and industrialist Willhem Kepler. His first car, and his first rotary engines were built in the 1920s and 1930s. Advertisement Some argue that Wankel may be a brutally misunderstood character — that his Nazi ties were only to support his technical career , that he was making a deal with the devil, so to speak. It does not appear that there is evidence to support this theory. I think you can gather that Wankel wasn't a casual member of the Nazi party. He was booted out once (if not twice) for being too radical. The guy was a Nazi. Advertisement Photo Credits: Getty Images/Mazda, Der-Wankelmotor.de Advertisement Popplow, Marcus. Felix Wankel: Mehr als ein Erfinderleben .

Erfurt; Sutton Verlag, 2011. "Erfinder und politisch wankelmütig," Badische Zeitung, August 13, 2011. This article can be found right here . Advertisement Hagedorn, Jutta. "Technisches Genie mit Schattenseiten," Badisches Stadtarchiv, August 10, 2002. This article can be found right here . Felix Wankel | German inventor | Britannica.com German inventor Otto von Guericke Felix Wankel, (born Aug. 13, 1902, Lahr, Ger.—died Oct. 9, 1988, Lindau , W.Ger.), German engineer and inventor of the Wankel rotary engine. The Wankel engine is radically different in structure from conventional reciprocating piston engines. Instead of having pistons that move up and down in cylinders, the Wankel engine has a triangular orbiting rotor that turns in a closed chamber.

Each quarter turn of the rotor completes an expansion or a compression of the gases inside the chamber, permitting the four functions characteristic of all internal-combustion engines—intake, compression, expansion, and exhaust—to be accomplished during one turn of the rotor. The only moving parts are the rotor and the output shaft. In theory, the advantages of this design include its light weight, few moving parts, compactness, low initial cost, fewer needed repairs, and relatively smooth performance. Felix Wankel, inventor of the Wankel engine, a rotary internal-combustion engine (RCE). © dpa/Corbis Wankel never earned an engineering degree or acquired a driver’s license. The son of a forestry official in the Black Forest region of southern Germany , he grew up in straitened circumstances after his father was killed in World War I . As a young man, convinced that he could design a practical rotary engine (the concept was well known but usually dismissed as unworkable), he set up a small engineering business in Heidelberg while financing himself with other jobs such as bookselling. He was briefly a member of the Nazi Party before it rose to power.

During the Nazi period and World War II he lived in Lindau, on Lake Constance (near the border with Switzerland), where he worked on designs for seals, unconventional rotary valves, and rotary engines for automobile and airplane engines. At various times he worked for the Daimler-Benz and BMW automobile companies as well as the German air force. At the end of the war, Wankel’s workshop was dismantled by the Allied authorities, and in 1951 he began working in Lindau with the research department of an engine manufacturer, NSU Motorenwerk AG. He completed his first design of a rotary engine for NSU in 1954, and prototype units were tested in 1957 and 1958. In 1961 Mazda , a Japanese automobile company, contracted with NSU to produce and develop the Wankel engine in Japan. Rotary-engine Mazda cars were introduced to the Japanese market in the 1960s and to the American market in 1971. Wankel established a series of his own research establishments at Lindau, where he continued to work under contract for various companies on the fundamental problems and future applications of the rotary engine.

Britannica Stories Felix Wankel - Rotary Engine Wiki Felix Wankel <google uid="C01"></google> Felix Wankel Prof.hc.Dr.Ing.e.h. Felix Heinrich Wankel フェリクス・ヴァンケル (August 13, 1902-October 9, 1988) was the German inventor of the Wankel engine . Wankel was born in Lahr, Germany, in the upper Rhine Valley. Since his mother was widowed in World War I, Wankel received no university education or even an apprenticeship. However he was able to teach himself technical subjects and conceived the idea of the Wankel engine in 1924. In the 1930s, he had a disagreement with Adolf Hitler, and was imprisoned by the Nazis for some months. During World War II, he developed seals and rotary valves for German air force aircraft and navy torpedoes. After the war, he was imprisoned by the Allies for some months, his laboratory was closed, his work confiscated, and he was prohibited from doing more work.

In 1951, he began development of the engine at NSU (NSU Motorenwerke AG) , leading to the first running prototype on February 11 1957. His Wankel engine design was first licensed by Curtiss Wright in New Jersey. Mazda in Japan solved the chatter marks problem. The engine has been successfully used by Mazda in several generations of their RX-series of coupés. In later years, Wankel was granted an honorary Doctorate of Engineering (Dr.-Ing.). He was known for his championing of animal rights and opposition to the use of animals in testing. He never had a driver's license. Felix Wankel died in Heidelberg. Dr Felix Wankel - A brief history of the Inventor and Engineer Dr Felix Wankel (13 August 1902 - 9 October 1988) Thinking on tangents rather than laterally he has been called legendary, brilliant, a master engineer and even egotistical, amateurish, eccentric, fanatical and futile. The word that will always be Felix Wankel to me is "genius".

He was, to this day, one of the few engineering minds of the modern era who did not believe the more conventional, but infinitely more complex, reciprocating engine was the ultimate answer. He believed it could be done better and more easily and spent most of his life on a project that would eventually realise this belief. Hence begins the story of the Wankel Rotary Engine. A story that, thanks to Felix, can now be told with a happy ending. The promising thing is, the story does not really end there and even today, thousands of people all over the world are still working hard at developing and refining this revolutionary engine. From the enthusiast in his garage, busily porting his next set of housings to the big budget race teams developing new hard wearing materials for use in high performance race engines. The world of Rotary engines just gets bigger every day and with large multinationals like Mazda still pouring millions into Rotary research and development, our favourite engine looks to be alive and well heading into the next millennium.

Felix Wankel was born an only son to Rudolf and Martha Wankel on 13 August 1902 in Lahr, a small town in the Swabia district, South Western Germany near the Swiss border. It is this area of Germany where Wankel would live out almost his entire life. The inhabitants of this particular area, although jokingly known to be stupid, somewhat crude people, have in reality produced some of engineering's finest minds when it comes to twentieth century engine design. Not far from Wankel's village is the town of Stuttgart, home to names like Daimler, Otto and Benz, known for their refinement of the conventional reciprocating engine and of course the revolutionary diesel engine. At age twelve, Wankel was left fatherless in the first months of the Great War. Money his fathers estate had left the family was all but wiped out by skyrocketing inflation during the 1920s, basically preventing an already less than keen Wankel from attending either a technical type secondary school or seeking an apprenticeship in an engineering field. Personally Wankel felt that school was a bit of a bore.

From 1921 to 1924 Wankel was employed at the University book shop in Heildelberg, dealing mainly in scientific publications. Suffering a kidney complaint during his time there, he was transferred from the printing room away from the lead type, and was positioned in the storeroom where he quickly devised a new and more efficient way to stack books very high without risk of the pile falling. He did this by arranging the books in an unconventional fashion to maximise the stability of the stack. Such was the fertility of his mind that he would constantly see a better way to do things in all aspects of life. Of course this position supplied him with almost limitless amounts of research material to pour over and it was at this time he was also attending night school and completing a correspondence course, building the knowledge base that we know today resulted in the Rotary engine design. He would, later be awarded an Honorary Doctorate from the Technical University of Munich, recognising his contributions to engineering science in 1969. In 1924, he began his work on the Rotary engine while still in the employ of the university book shop.

This work, though on and off in nature, would last him most of his productive life and he would be employed by many various people over time seeking to tap into the genius of his mind that must have been obvious to any observer. Wankel was known for his unusual, some would say, undisciplined attitude toward seeing an idea through to it's ultimate, refined form. Opting rather to abandon his research and quickly move on to his next project with almost boyish enthusiasm as soon as a previous idea had reached a stage of successful operation, meeting with his personally strict testing doctrine. To the bewilderment, and sometimes, annoyance of his colleagues Wankel would often behave indifferently to the pleas and enquiries from those still engaged in refining what he had long considered past projects, far to distracted by his latest ideas to backtrack. My analogy is that Wanklel would be happy to build the finest of houses but leave the gardens and landscaping to someone else as he is off, busy improving on his designs elsewhere.felix During the WW2 years, at times for Hitler's own war effort, Wankel was involved in the development of a rotary disc type valve for use in aircraft and torpedo engines.

The Rotary engine project was somewhat shelved during this time. Later, Wankel was employed by, collaborated with and advised many different organisations over the years including BMW, Daimler-Benz, DVL, Junker Aircraft and NSU. It was during this time, working professionally on various projects for others, that he also privately continued working on his own many ideas such as designs for compressors and pumps, but more importantly the embryonic sketches for what was to become the first of the DKM (Drehkolbenmotor - or Rotary Piston Motor) engines. Early in 1957, this DKM engine would run for the first time, however it would be some months of hard work before a successful 2 hour test could be completed, eventually turning in a peak of a little over 20 horsepower. His later design, the KKM (Krieskolbenmotor - Translation please??) engine would first run in July 1958. Wankel lived out his later years quietly, still turning in long hours of research and testing in his private facility, the Institute, at his home in Swabia and as always maintained his reclusive nature.

Up until the early seventies he had always been satisfied with an old Borgward saloon as his car when he was given a Rotary engined NSU Ro80. He died on 9 October 1988 in Lindau, West Germany. Wankel's extensive working life and various affiliations with different people are too complex and far reaching to present here in any great detail and will be the subject of a future essay. by G Anderson Honorary doctorate degree from Technische Universität München, December 5, 1969. The Federation of German Engineers (VDI) Gold Medal, 1969. The Grand Federal Service Cross, Germany's highest civilian honor, 1970 The Franklin Medal, Philadelphia, Pennsylvania, 1971. The Bavarian Service Medal, 1973. The "Honour Citizen" of Lahr,1981, and the title of Professor in 1987. The Soichiro Honda Medal, 1987.

Honorary citizenship of Lindau (declined) See also Wankel engine | Tractor & Construction Plant Wiki | Fandom powered by Wikia Tractor & Construction Plant Wiki A Wankel engine in Deutsches Museum in Munich, Germany The Mazda RX-8 , a sports car powered by a Wankel engine The Wankel engine is a type of internal combustion engine that uses a rotary design to convert pressure into a rotating motion instead of using reciprocating pistons . Its four-stroke cycle takes place in a space between the inside of an oval-like epitrochoid -shaped housing and a rotor that is similar in shape to a Reuleaux triangle but with sides that are somewhat flatter. This design delivers smooth high- rpm power from a compact size. It is the only internal combustion engine invented in the twentieth century to go into production. [1] Since its introduction the engine has been commonly referred to as the rotary engine, though this name is also applied to several completely different designs . The engine was invented by German engineer Felix Wankel.

He received his first patent for the engine in 1929, began development in the early 1950s at NSU Motorenwerke AG (NSU), and completed a working prototype in 1957. [1] NSU then licensed the concept to companies around the world, which have continued to improve the design. Because of their compact design, Wankel rotary engines have been installed in a variety of vehicles and devices such as automobiles (including racing cars ), along with aircraft , go-karts , personal water craft, chain saws , and auxiliary power units . The most extensive automotive use of the Wankel engine has been by the Japanese company Mazda .

Contents First DKM Wankel Engine DKM 54 (Drehkolbenmotor), at the Deutsches Museum in Bonn, Germany First KKM Wankel Engine NSU KKM 57P (Kreiskolbenmotor), at Autovision und Forum, Germany In 1951, the German engineer Felix Wankel began development of the engine at NSU Motorenwerke AG , where he first conceived his rotary engine in 1954 (DKM 54, Drehkolbenmotor). The so-called KKM 57 (the Wankel rotary engine, Kreiskolbenmotor) was constructed by NSU engineer Hanns Dieter Paschke in 1957 without the knowledge of Felix Wankel, who remarked "you've turned my race horse into a plow mare". [2] The first working prototype DKM 54 was running on February 1, 1957 at the NSU research and development department Versuchsabteilung TX. [3] It produced 21 horsepower; unlike modern Wankel engines, both the rotor and the housing rotated.

[1] Considerable effort went into designing rotary engines in the 1950s and 1960s. They were of particular interest because they were smooth and quiet running, and because of the reliability resulting from their simplicity. An early problem of buildup of cracks in the epitrochoid surface was solved by installing the spark plugs in a separate metal piece instead of screwing them directly into the block.[ citation needed ] Among the manufacturers signing licensing agreements to develop Wankel engines were Alfa Romeo , American Motors , Citroen , Ford , General Motors , Mercedes-Benz , Nissan , Porsche , Rolls-Royce , Suzuki , and Toyota . [1] In the United States, in 1959 under license from NSU, Curtiss-Wright pioneered minor improvements in the basic engine design. In Britain, in the 1960s, Rolls Royce Motor Car Division pioneered a two-stage diesel version of the Wankel engine.

[4] Also in Britain, Norton Motorcycles developed a Wankel rotary engine for motorcycles , based on the Sachs air cooled Wankel that powered the DKW/Hercules W-2000 motorcycle, which was included in their Commander and F1 ; Suzuki also made a production motorcycle with a Wankel engine, the RE-5, where they used ferrotic alloy apex seals and an NSU rotor in a successful attempt to prolong the engine's life. In 1971 and 1972 Arctic Cat produced snowmobiles powered by 303 cc Wankel rotary engines manufactured by Sachs in Germany. Deere & Company designed a version that was capable of using a variety of fuels. The design was proposed as the power source for United States Marine Corps combat vehicles and other equipment in the late 1980s. [5] Mazda and NSU signed a study contract to develop the Wankel engine in 1961 and competed to bring the first Wankel powered automobile to market.

Although Mazda produced an experimental Wankel that year, NSU was first with a Wankel automobile on sale, the sporty NSU Spider in 1964; Mazda countered with a display of two and four rotor Wankel engines at that year's Tokyo Motor Show . [1] In 1967, NSU began production of a Wankel engined luxury car, the Ro 80 . [6] However, problems with apex seal wear led to frequent engine failure, which led to large warranty costs for NSU, and curtailed further Wankel engine development. [1] Mazda 's first Wankel engine, at the Mazda Museum in Hiroshima, Japan Mazda, however, claimed to have solved the apex seal problem, and was able to run test engines at high speed for 300 hours without failure. [1] After years of development, Mazda's first Wankel engine car was the 1967 Cosmo 110S . The company followed with a number of Wankel ("rotary" in the company's terminology) vehicles, including a bus and a pickup truck . Customers often cited the cars' smoothness of operation.

However, Mazda chose a method to comply with hydrocarbon emission standards that, while less expensive to produce, increased fuel consumption, just before a sharp rise in fuel prices. Mazda later abandoned the Wankel in most of their automotive designs, but continued using it in their RX-7 sports car until August 2002 (RX-7 importation for Canada ceased with only the 1993 year being sold. The USA ended with the 1994 model year with remaining unsold stock being carried over as the '1995' year.). The company normally used two-rotor designs, but the 1991 Eunos Cosmo used a twin- turbo three-rotor engine. In 2003, Mazda introduced the Renesis engine with the RX-8 . The Renesis engine relocated the ports for exhaust and intake from the periphery of the rotary housing to the sides, allowing for larger overall ports, better airflow, and further power gains. Early Wankel engines had also side intake and exhaust ports, but the concept was abandoned because of carbon buildup in ports and side of rotor. The Renesis engine solved the problem by using a keystone scraper side seal.

[7] The Renesis is capable of delivering 238 hp (177 kW) with better fuel economy, reliability, and environmental friendliness than previous Mazda rotary engines, [8] all from its 1.3 L displacement. In 1961, the Soviet research organization of NATI, NAMI and VNIImotoprom started experimental development, and created experimental engines with different technologies. [9] Soviet automobile manufacturer AvtoVAZ also experimented with the use of Wankel engines in cars but without the benefit of a license . [10] In 1974 they created a special engine design bureau, which in 1978 designed an engine designated as VAZ-311. In 1980, the company started delivering Wankel-powered VAZ-2106s (VAZ-411 engine with two-rotors) and Ladas , mostly to security services, of which about 200 were made. [11] [12] The next models were the VAZ-4132 and VAZ-415.

Aviadvigatel , the Soviet aircraft engine design bureau, is known to have produced Wankel engines with electronic injection for aircraft and helicopters, though little specific information has surfaced. Although many manufacturers licensed the design, including Citroën with their M35 and GS Birotor , using engines produced by Comotor , General Motors , which seems to have concluded that the Wankel engine was slightly more expensive to build than an equivalent reciprocating engine, and Mercedes-Benz which used it for their C111 concept car, only Mazda has produced Wankel engines in large numbers. American Motors (AMC) was so convinced "...that the rotary engine will play an important role as a powerplant for cars and trucks of the future...", according to Chairman Roy D. Chapin Jr. , that the smallest U.S. automaker signed an agreement in February 1973, after a year's negotiations, to build Wankels for both passenger cars and Jeeps , as well as the right to sell any rotary engines it produces to other companies.

[13] [14] It even designed the unique Pacer around the engine, even though by then, AMC had decided to buy the Wankel engines from GM instead of building them itself. However, GM's engines had not reached production when the Pacer was to hit the showrooms. Part of the demise of this feature was the 1973 oil crisis with rising fuel prices, and also concerns about proposed US emission standards legislation. General Motors' Wankel did not comply with those emission standards, so in 1974 the company canceled its development, although GM claimed having solved the fuel consumption problem; unfortunately, they never published the results of their research. This meant the Pacer had to be reconfigured to house AMC's venerable AMC Straight-6 engine with rear-wheel drive Design Edit The Wankel cycle. The "A" marks one of the three apexes of the rotor. The "B" marks the eccentric shaft and the white portion is the lobe of the eccentric shaft. The shaft turns three times for each rotation of the rotor around the lobe and once for each orbital revolution around the eccentric shaft.

In the Wankel engine, the four strokes of a typical Otto cycle occur in the space between a three-sided symmetric rotor and the inside of a housing. The expansion phase of the Wankel cycle is much longer than that of the Otto cycle. [15] In the basic single-rotor Wankel engine, the oval-like epitrochoid -shaped housing surrounds a rotor which is triangular with bow-shaped flanks (often confused with a Reuleaux triangle , [16] a three-pointed curve of constant width , but with the bulge in the middle of each side a bit more flattened). The theoretical shape of the rotor between the fixed corners is the result of a minimization of the volume of the geometric combustion chamber and a maximization of the compression ratio , respectively. [15] The symmetric curve connecting two arbitrary apexes of the rotor is maximized in the direction of the inner housing shape with the constraint that it not touch the housing at any angle of rotation (an arc is not a solution of this optimization problem ). The central drive shaft, called the eccentric shaft or E-shaft, passes through the center of the rotor and is supported by fixed bearings.

[17] The rotors ride on eccentrics (analogous to cranks) integral to the eccentric shaft (analogous to a crankshaft). The rotors both rotate around the eccentrics and make orbital revolutions around the eccentric shaft. Seals at the corners of the rotor seal against the periphery of the housing, dividing it into three moving combustion chambers . [15] The rotation of each rotor on its own axis is caused and controlled by a pair of synchronizing gears [17] A fixed gear mounted on one side of the rotor housing engages a ring gear attached to the rotor and ensures the rotor moves exactly 1/3 turn for each turn of the eccentric shaft. The power output of the engine is not transmitted through the synchronizing gears. [17] The force of gas pressure on the rotor (to a first approximation) goes directly to the center of the eccentric, part of the output shaft. The best way to visualize the action of the engine in the animation at left is to look not at the rotor itself, but the cavity created between it and the housing. The Wankel engine is actually a variable-volume progressing-cavity system.

Thus there are 3 cavities per housing, all repeating the same cycle. Note as well that points A and B on the rotor and e-shaft turn at different speed, point B moves 3 times faster than point A, so that one full orbit of the rotor equates to 3 turns of the e-shaft. As the rotor rotates and orbitally revolves, each side of the rotor is brought closer to and then away from the wall of the housing, compressing and expanding the combustion chamber like the strokes of a piston in a reciprocating engine . The power vector of the combustion stage goes through the center of the offset lobe. While a four-stroke piston engine makes one combustion stroke per cylinder for every two rotations of the crankshaft (that is, one-half power stroke per crankshaft rotation per cylinder), each combustion chamber in the Wankel generates one combustion stroke per each driveshaft rotation, i.e. one power stroke per rotor orbital revolution and three power strokes per rotor rotation.

Thus, power output of a Wankel engine is generally higher than that of a four-stroke piston engine of similar engine displacement in a similar state of tune; and higher than that of a four-stroke piston engine of similar physical dimensions and weight. Wankel engines also generally have a much higher redline than a reciprocating engine of similar power output. This is in part because the smoothness inherent in circular motion, but especially because they do not have highly stressed parts such as a crankshaft or connecting rods. Eccentric shafts do not have the stress-raising internal corners of crankshafts. The redline of a rotary engine is limited by wear of the synchronizing gears[ citation needed ]. Hardened steel gears are used for extended operation above 7000 or 8000 rpm. Mazda Wankel engines in auto racing are operated above 10,000 rpm. In aircraft they are used conservatively, up to 6500 or 7500 rpm. However, as gas pressure participates in seal efficiency, running a Wankel engine at high rpm under no load conditions can destroy the engine.

National agencies that tax automobiles according to displacement and regulatory bodies in automobile racing variously consider the Wankel engine to be equivalent to a four-stroke engine of 1.5 to 2 times the displacement; some racing series ban it altogether. [18] Engineering Edit Apex seals, left NSU Ro80 Serie and Research and right Mazda 12A and 13B Left Mazda old L10A Camber axial cooling, middle Audi NSU EA871 axial water cooling only hot bow, right Diamond Engines Wankel radial cooling only in the hot bow Felix Wankel managed to overcome most of the problems that made previous rotary engines fail by developing a configuration with vane seals that could be made of more durable materials than piston ring metal that led to the failure of previous rotary designs. [19] Rotary engines have a thermodynamic problem not found in reciprocating four-stroke engines in that their "cylinder block" operates at steady state, with intake, compression, combustion, and exhaust occurring at fixed housing locations for all "cylinders".

In contrast, reciprocating engines perform these four strokes in one chamber, so that extremes of "freezing" intake and "flaming" exhaust are averaged and shielded by a boundary layer from overheating working parts. The boundary layer shields and the oil film act as thermal insulation, leading to a low temperature of the lubricating film (max. ~200 °C/400 °F) on a water-cooled Wankel engine. This gives a more constant surface temperature. The temperature around the spark plug is about the same as the temperature in the combustion chamber of a reciprocating engine. With circumferential or axial flow cooling, the temperature difference remains tolerable. [20] [21] [22] [23] Four-stroke reciprocating engines are less suitable for hydrogen. The hydrogen can misfire on hot parts like the exhaust valve and spark plugs. Another problem concerns the hydrogenate attack on the lubricating film in reciprocating engines. In a Wankel engine, this problem is circumvented by using a ceramic apex seal against a ceramic surface: there is no oil film to suffer hydrogenate attack.

Since ceramic piston rings are not available as of 2009 [update] , the problem remains with the reciprocating engine. The piston shell must be lubricated and cooled with oil. This substantially increases the lubricating oil consumption in a four-stroke hydrogen engine. [24] [25] Materials Edit Unlike a piston engine, where the cylinder is cooled by the incoming charge after being heated by combustion, Wankel rotor housings are constantly heated on one side and cooled on the other, leading to high local temperatures and unequal thermal expansion . While this places high demands on the materials used, the simplicity of the Wankel makes it easier to use alternative materials like exotic alloys and ceramics . With water cooling in a radial or axial flow direction, with the hot water from the hot bow heating the cold bow, the thermal expansion remains tolerable. [26] Sealing Edit Early engine designs had a high incidence of sealing loss, both between the rotor and the housing and also between the various pieces making up the housing. Also, in earlier model Wankel engines carbon particles could become trapped between the seal and the casing, jamming the engine and requiring a partial rebuild.

It was common for very early Mazda engines to require rebuilding after 50,000 miles (80,000 km). Further sealing problems arise from the uneven thermal distribution within the housings causing distortion and loss of sealing and compression. This thermal distortion also causes uneven wear between the apex seal and the rotor housing, quite evident on higher mileage engines.[ citation needed ] The problem is exacerbated when the engine is stressed before reaching operating temperature . However, Mazda Wankel engines have solved these problems. Current engines have nearly 100 seal-related parts. [1] Fuel consumption and emissions Edit Just as the shape of the Wankel combustion chamber is resistant to preignition and will run on lower- octane rating gasoline than a comparable piston engine, [27] it also leads to relatively incomplete combustion of the air-fuel charge, with a larger amount of unburned hydrocarbons released into the exhaust.

The exhaust is, however, relatively low in NOx emissions; this allowed Mazda to meet the United States Clean Air Act of 1970 in 1973 with a simple and inexpensive 'thermal reactor' (an enlarged open chamber in the exhaust manifold ) by paradoxically enriching the air-fuel ratio to the point where the unburned hydrocarbons (HC) in the exhaust would support complete combustion in the thermal reactor; while piston-engine cars required expensive catalytic converters to deal with both unburned hydrocarbons and NOx emissions. This raised fuel consumption, however, (already a weak point for the Wankel engine) at the same time that the oil crisis of 1973 raised the price of gasoline. Mazda was able to improve the fuel efficiency of the thermal reactor system by 40% by the time of introduction of the RX-7 in 1978, but eventually shifted to the catalytic converter system. [17] According to the Curtiss-Wright research, the extreme that controls the amount of unburned HC in the exhaust is the rotor surface temperature, higher temperatures producing less HC. [28] They showed also that the rotor can be widened.

Quenching is the dominant source of HC at high speeds, and leakage at low speeds. [29] The shape and positioning of rotor recess-combustion chamber- influences emissions and fuel use, the MDR being chosen as a compromise. [30] In Mazda's RX-8 with the Renesis engine, fuel consumption is now within normal limits while passing California State emissions requirements, including California's Low Emissions Vehicle or LEV standards. The exhaust ports, which in earlier Mazda rotaries were located in the rotor housings, were moved to the sides of the combustion chamber. This approach allowed Mazda to eliminate overlap between intake and exhaust port openings, while simultaneously increasing exhaust port area. The side port trapped the unburned fuel in the chamber decreased the oil consumption and improved the combustion stability in the low-speed and light load range. The HC emissions from the side exhaust port Wankel engine is 35 to 50 percent less than those from the peripheral exhaust port Wankel engine.

[31] [32] Advantages NSU Wankel Spider, the first line of cars sold with a rotor Wankel engine Mazda Cosmo , the first series two rotor Wankel engine sports car Wankel engines are considerably simpler, lighter, and contain far fewer moving parts than piston engines of equivalent power output. For instance, because valving is accomplished by simple ports cut into the walls of the rotor housing, they have no valves or complex valve trains ; in addition, since the rotor rides directly on a large bearing on the output shaft, there are no connecting rods and there is no crankshaft . The elimination of reciprocating mass and the elimination of the most highly stressed and failure prone parts of piston engines gives the Wankel engine high reliability, a smoother flow of power, and a high power-to-weight ratio. The surface/volume-ratio problem is so complex that one cannot make a direct comparison between a reciprocating piston engine and a Wankel engine in terms of the surface/volume-ratio. The flow velocity and the heat losses behave quite differently. Surface temperatures behave absolutely differently; the film of oil in the Wankel engine acts as insulation.

Engines with a higher compression ratio have a worse surface/volume-ratio. The surface/volume-ratio of a Diesel engine is much worse than a gasoline engine, but Diesel engines are well known for a higher efficiency factor than gasoline engines. Thus, engines with equal power should be compared: a naturally aspirated 1.3-liter Wankel engine with a naturally aspirated 1.3-liter four-stroke reciprocating piston engine with equal power. But such a four-stroke engine is not possible and needs twice the displacement for the same power as a Wankel engine. The extra or "empty" stroke(s) should not be ignored, as a 4-stroke cylinder produces a power stroke only every other rotation of the crankshaft. In actuality, this doubles the real surface/volume-ratio for the four-stroke reciprocating piston engine and the demand of displacement. [33] [34] The Wankel, therefore, has higher volumetric efficiency and a lower pumping loss through the absence of choking valves.

[35] Because of the quasi-overlap of the power strokes that cause the smoothness of the engine and the avoidance of the 4-stroke cycle in a reciprocating engine, the Wankel engine is very quick to react to throttle changes and is able to quickly deliver a surge of power when the demand arises, especially at higher rpm. This difference is more pronounced when compared to four-cylinder reciprocating engines and less pronounced when compared to higher cylinder counts. In addition to the removal of internal reciprocating stresses by virtue of the complete removal of reciprocating internal parts typically found in a piston engine, the Wankel engine is constructed with an iron rotor within a housing made of aluminium , which has a greater coefficient of thermal expansion . This ensures that even a severely overheated Wankel engine cannot seize, as would be likely to occur in an overheated piston engine. This is a substantial safety benefit of use in aircraft. In addition, valves and valve trains that do not exist cannot burn out, jam, break, or malfunction in any way, again increasing safety.

A further advantage of the Wankel engine for use in aircraft is the fact that a Wankel engine generally has a smaller frontal area than a piston engine of equivalent power, allowing a more aerodynamic nose to be designed around it. The simplicity of design and smaller size of the Wankel engine also allows for savings in construction costs, compared to piston engines of comparable power output. Wankel engines that operate within their original design parameters are almost immune to catastrophic failure. A Wankel engine that loses compression, cooling or oil pressure will lose a large amount of power, and will die over a short period of time; however, it will usually continue to produce some power during that time. Piston engines under the same circumstances are prone to seizing or breaking parts that almost certainly results in major internal damage of the engine and an instant loss of power. For this reason, Wankel engines are very well suited to snowmobiles and aircraft, which often take users into remote places where a failure could result in frostbite or death. Due to a 50% longer stroke duration compared to a four-cycle engine, there is more time to complete the combustion. This leads to greater suitability for direct injection .

A Wankel rotary engine has stronger flows of air-fuel mixture and a longer operating cycle than a reciprocating engine, so it realizes concomitantly thorough mixing of hydrogen and air. The result is a homogeneous mixture, which is crucial for hydrogen combustion. [36] Disadvantages Edit Rolls Royce R6 two stage Wankel Diesel engine Although in two dimensions the seal system of a Wankel looks to be even simpler than that of a corresponding multi-cylinder piston engine, in three dimensions the opposite is true. As well as the rotor apex seals evident in the conceptual diagram, the rotor must also seal against the chamber ends. Piston rings are not perfect seals: each has a gap to allow for expansion. The sealing at the Wankel apexes is less critical, as leakage is between adjacent chambers on adjacent strokes of the cycle, rather than to the crankcase. However, the less effective sealing of the Wankel is one factor reducing its efficiency,[ citation needed ] limiting its use mainly to applications such as racing engines and sports vehicles where neither efficiency nor long engine life are major considerations.

Comparison tests have shown that the Mazda rotary powered RX-8 uses more fuel than a heavier vehicle powered by larger displacement V-8 engine for similar performance results. [37] The time available for fuel to be port-injected into a Wankel engine is significantly shorter, compared to four-stroke piston engines, due to the way the three chambers rotate. The fuel-air mixture cannot be pre-stored as there is no intake valve. Also the Wankel engine, compared to a piston engine, has 50% longer stroke duration. The four Otto cycles last 1080° for a Wankel engine versus 720° for a four-stroke reciprocating piston engine. There are various methods of calculating the engine displacement of a Wankel. The Japanese regulations for calculating displacements for engine ratings use the volume displacement of one rotor face only, and the auto industry commonly accepts this method as the standard for calculating the displacement of a rotary. However, when compared on the basis of specific output, the convention results in large imbalances in favor of the Wankel motor.

For comparison purposes between a Wankel Rotary engine and a piston engine, displacement and corresponding power output can more accurately be compared on the basis of displacement per revolution of the eccentric shaft. A calculation of this form dictates that a two rotor Wankel displacing 654 cc per face will have a displacement of 1.3 liters per every rotation of the eccentric shaft (only two total faces, one face per rotor going through a full power stroke) and 2.6 liters after two revolutions (four total faces, two faces per rotor going through a full power stroke). The results are directly comparable to a 2.6-liter piston engine with an even number of cylinders in a conventional firing order, which will likewise displace 1.3 liters through its power stroke after one revolution of the crankshaft, and 2.6 liters through its power strokes after two revolutions of the crankshaft. A Wankel Rotary engine is still a 4-stroke engine and pumping losses from non-power strokes still apply, but the absence of throttling valves and a 50% longer stroke duration result in a significantly lower pumping loss compared against a four-stroke reciprocating piston engine.

Measuring a Wankel rotary engine in this way more accurately explains its specific output, as the volume of its air fuel mixture put through a complete power stroke per revolution is directly responsible for torque and thus power produced. The trailing side of the rotary engine's combustion chamber develops a squeeze stream which pushes back the flamefront. With the conventional two-spark-plug or one-spark-plug system and homogenous mixture, this squeeze stream prevents the flame from propagating to the combustion chamber's trailing side in the mid and high engine speed ranges. This is why there can be more carbon monoxide and unburnt hydrocarbons in a Wankel's exhaust stream. A side-port exhaust, as is used in the Renesis , avoids this because the unburned mixture cannot escape. The Mazda 26B avoided this issue through a 3-spark plug ignition system. (As a result, at the Le Mans 24 hour endurance race in 1991, the 26B had significantly lower fuel consumption than the competing reciprocating piston engines.

All competitors had only the same amount of fuel available, because of the Le Mans 24 h limited fuel quantity rule.) [38] A peripheral intake port gives the highest MEP, however, side intake porting produces a more steady idle. [39] All Mazda-made Wankel rotaries, including the new Renesis found in the RX-8 , burn a small quantity of oil by design; it is metered into the combustion chamber to preserve the apex seals. Owners must periodically add small amounts of oil, marginally increasing running costs — though it is still reasonable and comparable in some instances when compared to many reciprocating piston engines. Applications Mazda 787B In the racing world, Mazda has had substantial success with two-rotor, three-rotor, and four-rotor cars. Private racers have also had considerable success with stock and modified Mazda Wankel-engine cars. [40] The Sigma MC74 powered by a Mazda 12A engine was the first engine and only team from outside Western Europe or the United States to finish the entire 24 hours of the 24 Hours of Le Mans race , in 1974.

Mazda is the only team from outside Western Europe or the United States to have won Le Mans outright and the only non-piston engine ever to win Le Mans, which the company accomplished in 1991 with their four-rotor 787B (2,622 cc/160 cu in—actual displacement, rated by FIA formula at 4,708 cc/287 cu in). The following year, a planned rule change at Le Mans made the Mazda 787B ineligible to race anymore due to weight advantages.[ citation needed ] The Mazda RX-7 has won more IMSA races in its class than any other model of automobile, with its one hundredth victory on September 2, 1990. Following that, the RX-7 won its class in the IMSA 24 Hours of Daytona race ten years in a row, starting in 1982. The RX7 won the IMSA Grand Touring Under Two Liter (GTU) championship each year from 1980 through 1987, inclusive.

Formula Mazda Racing features open-wheel race cars with Mazda Wankel engines , adaptable to both oval tracks and road courses, on several levels of competition. Since 1991, the professionally organized Star Mazda Series has been the most popular format for sponsors, spectators, and upward bound drivers. The engines are all built by one engine builder, certified to produce the prescribed power, and sealed to discourage tampering. They are in a relatively mild state of racing tune, so that they are extremely reliable and can go years between motor rebuilds. [41] The Malibu Grand Prix chain, similar in concept to commercial recreational kart racing tracks, operates several venues in the United States where a customer can purchase several laps around a track in a vehicle very similar to open wheel racing vehicles, but powered by a small Curtiss-Wright rotary engine. In engines having more than two rotors, or two rotor race engines intended for high-rpm use, a multi-piece eccentric shaft may be used, allowing additional bearings between rotors. While this approach does increase the complexity of the eccentric shaft design, it has been used successfully in the Mazda's production three-rotor 20B-REW engine, as well as many low volume production race engines.

(The C-111-2 4 Rotor Mercedes-Benz eccentric shaft for the KE Serie 70, Typ DB M950 KE409 is made in one piece. Mercedes-Benz used split bearings.) Motorcycle engines Edit Norton Interpol2 prototype From 1974 to 1977 Hercules produced a limited number of motorcycles powered by Wankel engines. [42] The motor tooling and blank apex seals were later used by Norton to produce the Norton Commander model in the early 1980s. [43] The Suzuki RE5 was a Wankel-powered motorcycle produced in 1975 and 1976. It was touted as the future of motorcycling, however, other problems and a lack of parts interchangeability meant low sales. [44] Dutch motorcycle importer and manufacturer van Veen produced small quantities of their dual rotor Wankel-engined OCR-1000 between 1978 and 1980, using surplus Comotor engines. However, from the 1980s onwards, rotary engines have not been produced for sale to the general public for road use.

Norton has used a Wankel engine in several models including the F1, F1 Sports, RC588, RCW588, NRS588, most notably Steve Hislop riding to various victories on Norton's F1 in the TT in 1992. Norton now makes a 588cc twin-rotor model called the NRV588 and is in the process of making a 700cc version called the NRV700. [45] Aircraft engines Diamond DA20 with Diamond Engines Wankel Sikorsky Cypher UAV powered with a UEL AR801 Wankel engine The first Wankel rotary-engine aircraft was the experimental Lockheed Q-Star civilian version of the United States Army 's reconnaissance QT-2, basically a powered Schweizer sailplane , in 1968 or 1969. It was powered by a 185 hp (138 kW) Curtiss-Wright RC2-60 Wankel rotary engine. [46] Aircraft Wankels have made something of a comeback in recent years. None of their advantages have been lost in comparison to other engines.

They are increasingly being found in roles where their compact size and quiet operation is important, notably in drones, or UAVs . Many companies and hobbyists adapt Mazda rotary engines (taken from automobiles) to aircraft use; others, including Wankel GmbH itself, manufacture Wankel rotary engines dedicated for the purpose. [47] [48] One such use are the "Rotapower" engines in the Moller Skycar M400 . Wankel engines are also becoming increasingly popular in homebuilt experimental aircraft.[ citation needed ] Most are Mazda 12A and 13B automobile engines, converted to aviation use. This is a very cost-effective alternative to certified aircraft engines, providing engines ranging from 100 to 300 horsepower (220 kW) at a fraction of the cost of traditional engines. These conversions first took place in the early 1970s.

With a number of these engines mounted on aircraft, as of 10 December 2006 the National Transportation Safety Board has only seven reports of incidents involving aircraft with Mazda engines, and none of these were a failure due to design or manufacturing flaws.[ citation needed ] Peter Garrison, Contributing Editor for Flying magazine, has said that "the most promising engine for aviation use is the Mazda rotary." Mazdas have indeed worked well when converted for use in homebuilt aircraft. However, the real challenge in aviation is producing FAA-certified alternatives to the standard reciprocating engines that power most small general aviation aircraft. Mistral Engines, based in Switzerland, developed purpose-built rotaries for factory and retrofit installations on certified production aircraft. The G-190 and G-230-TS rotary engines were already flying in the experimental market, and Mistral Engines hoped for FAA and JAA certification by 2011. As of June 2010, G-300 rotary engine development ceased, with the company citing a need for cash flow to complete development.

[49] Mistral claims to have overcome the challenges of fuel consumption inherent in the rotary, at least to the extent that the engines are demonstrating specific fuel consumption within a few points of reciprocating engines of similar displacement. While fuel burn is still marginally higher than traditional engines, it is outweighed by other beneficial factors. [50] [51] Since Wankel engines operate at a relatively high rotational speed with relatively low torque, propeller aircraft must use a Propeller Speed Reduction Unit (PSRU) to keep conventional propellers within the proper speed range. There are many experimental aircraft flying with this arrangement. Pratt & Whitney Rocketdyne have been commissioned by DARPA to develop a diesel wankel engine for use in a prototype VTOL flying car called the "Transformer". [52] The engine, based on an earlier UAV diesel wankel concept called 'EnduroCORE', [53] will utilize wankel rotors of varying sizes on a shared eccentric shaft to increase efficiency. [54] The engine is claimed to be a 'full-compression, full-expansion, diesel-cycle engine'.

An October 28, 2010 patent from Pratt & Whitney Rocketdyne, describes a Wankel engine superficially similar to Rolls-Royce's earlier prototype that required an external air compressor to achieve high enough compression for diesel-cycle combustion. [55] [56] The design differs from Rolls-Royce's diesel wankel mainly by proposing an injector both in the exhaust passage between the combustor rotor and expansion rotor stages, and an injector in the expansion rotor's expansion chamber, for 'afterburning'. Other uses Edit UEL UAV-741 Wankel engine for a UAV Small Wankel engines are being found increasingly in other roles, such as go-karts , [57] [58] personal water craft and auxiliary power units for aircraft. [59] [60] The Graupner/ O.S. 49-PI is a 1.27 hp (947 W) 5 cc Wankel engine for model airplane use which has been in production essentially unchanged since 1970; even with a large muffler, the entire package weighs only 380 grams (13.4 ounces).

[61] [62] The simplicity of the Wankel makes it well-suited for mini, micro, and micro-mini engine designs. The Microelectromechanical systems (MEMS) Rotary Engine Lab at the University of California, Berkeley has been developing Wankel engines of down to 1 mm in diameter with displacements less than 0.1 cc. Materials include silicon and motive power includes compressed air. The goal is to eventually develop an internal combustion engine that will deliver 100 milliwatts of electrical power; the engine itself will serve as the rotor of the generator , with magnets built into the engine rotor itself. [63] [64] The largest Wankel engine was built by Ingersoll-Rand ; available in 550 hp (410 kW) one rotor and 1,100 hp (820 kW) two rotor versions, displacing 41 liters per rotor with a rotor approximately one meter in diameter. It was available between 1975 and 1985.

It was derived from a previous, unsuccessful Curtiss-Wright design, which failed because of a well-known problem with all internal combustion engines : the fixed speed at which the flame front travels limits the distance combustion can travel from the point of ignition in a given time, and thereby limiting the maximum size of the cylinder or rotor chamber which can be used. This problem was solved by limiting the engine speed to only 1200 rpm and the use of natural gas as fuel; this was particularly well chosen, since one of the major uses of the engine was to drive compressors on natural gas pipelines .

[65] Yanmar Diesel of Japan, produced some small, charge cooled rotor rotary engines for uses such as chainsaws and outboard engines, [66] some of their contributions are that the LDR (rotor recess in the leading edge of combustion chamber) engines had better exhaust emissions profiles, and that reed-valve controlled intake ports improve part-load and low RPM performance.(Kojiro Yamaoka & Hiroshi Tado, SAE paper 720466, 1972) In 2010 Audi revealed that in their electric car the A1 e-tron they would have a small 250 cc Wankel engine running at 5,000 rpm that would recharge the car's batteries as needed. [67] Non-internal combustion Edit In addition for use as an internal combustion engine, the basic Wankel design has also been utilized for gas compressors , and superchargers for internal combustion engines, but in these cases, although the design still offers advantages in reliability, the basic advantages of the Wankel in size and weight over the four-stroke internal combustion engine are irrelevant.

In a design using a Wankel supercharger on a Wankel engine, the supercharger is twice the size of the engine. The Wankel design is used in the seat belt pre-tensioner system [68] of some Mercedes-Benz [69] and Volkswagen [70] cars. When the deceleration sensors sense a potential crash, small explosive cartridges are triggered electrically and the resulting pressurized gas feeds into tiny Wankel engines which rotate to take up the slack in the seat belt systems, anchoring the driver and passengers firmly in the seat before a collision. [71] See also Urban Dictionary: wankel wankel A Rotary engine of extreme perfection which has been tested to speeds in excess of 18000 rpm the main component is a triangular driver, with three hardened rounded tips which rotate against a stater type outer cylinder. Masda have the monopoly on them and use them on the RX range. Earlier engines suffered from burnt out tips. My new Mazda RX8 will eat your Porsche for breakfast then spit it back out because it will have discovered that it had just eaten a jumped up VW beetle that Hitler commissioned...eeeegh! oooh i love my wankel.

Question: What type of engine did Felix Wankel invent?
Answer: Rotary