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Dr. Ing. Felix Heinrich Wankel (1902-1988)

Inventor and Developer of the Practical
Rotary Combustion Engine - Wankel RCE

  • 1921: Finished formal education (high school) age 19.
  • 1933: Applied for patent on a DKM engine.
  • 1936: Received patent.
  • 1951: Collaboration with NSU and Walter Froede.
  • 1957: DKM engine runs.
  • 1958: KKM engine runs.
  • 1969: Honorary Doctorate from Technische Universität Müinchen.

Felix Wankel was born August 13, 1902 at Schillerstrasse 11 (4?) in Lahr in the Black Forest in Swabia in Germany (Otto, Daimler, and Benz also came from Swabia). He was the only child of Rudolf Wankel (1867-1914), a senior forestry official (Grossh. Bad. Oberfoerster, Forstassessor, Forstbeamten), and Martha Gertrud (Gerty) Heidlauff (1879-?). His father was killed in August 1914 by schrapnel at Dornach (Elsass (Alsace?)) in World War I as an Oberleutnant.

Early Work

Wankel went to Unterprima High School, but he graduated from high school at the age of 19. Although the poverty of his family (widowed mother in postwar Germany) meant he had to go to work and could not apprentice or follow further full-time studies, he gained academic recognition within his own time. His first job was in 1921, printing, stocking, and apprenticing in sales for a scientific book publisher in Heidelberg, but Wankel devoted his energy to tinkering, especially after losing the sales job in 1924 in the German Depression. He opened his own workshop that year in Heidelberg.

Felix Wankel conceived the idea of a rotary engine in 1924. Wankel's first attempt to obtain a patent was in 1926 for a "grease turbine", but it was predated by an Enke design from 1886. In 1927 he made drawings of the shape of the "drehkolbenmaschine without uneven moved sections" or rotary piston engine and of sealing parts. He received his first patent in 1929 (DRP 507 584). He would continue to be issued patents for six decades. In 1933 he applied for a patent for a engine, which he received in 1936.

Like many middle class Germans of his time, ruined by the runaway inflation of the 1920's, Wankel had been attracted by the political and economic philosophies of national socialism. As a young man he was a member of the Hitler Youth where he met his wife, Emmy Kirn, and then a member of the NSDAP party. He resigned from it in 1932 which was the right idea, but there was no best time to do so, because in 1933 the Nazis came into power. This lead to conflict because Wankel had exposed some corruption by the provincial chief (Gauleiter) Wagner. He was arrested and held in prison by the Nazis for some months in Lahr until an industrialist and an engineer intervened on his behalf.

By 1936 he had resettled in the Lindau Bodensee area. In the following years, Wankel mostly made his way by ingenious work on rotary valves and sealing technology for Lilienthal, BMW, DVL, Junker, and Daimler-Benz. During this time he developed various DKM prototypes and also rotary pumps and compressors. When the French army invaded in 1945, his workshops and research were dismantled (destroyed) by the French and he was imprisoned until 1946.

Collaboration with NSU

During the Allied occupation, Felix Wankel began secretly writing his book on the organization of rotary piston engines. He was able to rebuild a research operation by 1951 when he interested NSU in development. This lead to collaboration with Walter Froede , head of the motorcycle racing program, who would ultimately make the decision to adopt the type.

The first truly functional Wankel rotary engine was a DKM type that ran in February 1957 . By May a prototype was able to run for two hours and produce 21 bhp. The first KKM engine ran on July 7, 1958.

Many people had proposed rotary engine designs, but none had pursued it for as long or as relentlessly as Felix Wankel. He and NSU rigorously investigated all technical aspects such as sealing, spark plug positioning, port timing, cooling, lubrication, combustion, materials, and manufacturing tolerances. Thus where all others had failed, he and NSU were able to succeed by combining imaginative invention and scientific engineering.

In 1957 Wankel had the good business sense to create Wankel GmbH with his partner at the time Ernst Hutzenlaub, to manage royalties. In August 1971 Wankel GmbH was sold to LonRho for 100 million DM ($26.3 million). He created a research institute (TES) in Lindau / Bodensee (in 1976?) as a branch of the Frauenhoffer Institute, but exercised an option to buy it back later. TES was supported by Daimler Benz until 1993.


Felix Wankel was awarded an honorary doctorate degree from Technische Universität München on December 5, 1969. He received the Federation of German Engineers Gold Medal in 1969, Germany's highest civilian honour the Grand Federal Service Cross in 1970, the Franklin Medal in Philadelphia in 1971, the Bavarian Service Medal in 1973, the "Honour Citizen" of Lahr in 1981, and the title of Professor in 1987.

He declined honorary citizenship of Lindau when the city rejected his application to build a boathouse with museum there. He set it up on the Swiss side of the Bodensee, partly as a satellite research institute (place to think), partly as a way to obtain Swiss citizenship, partly for taxes, and partly for neutrality in case of war.

Wankel never possessed a driver's license in his life. There are Felix-Wankel-Straße streets in Aalen, Dachau, Euskirchen, Heilbronn, Neckarsulm, Oldenburg, Ostfildern, Rottenburg, Schweinfurt, Sennfeld, Stuhr (Bremen), and Zaberfeld, and a Felix-Wankel-Ring in Lenting, all in Germany.


In 1986 he sold his Institute for 100 million DM to Daimler Benz. He was very active late in life, filing a patent in 1987 that was granted in Jan. 1989. After a long illness, Dr. Wankel passed away on October 9, 1988, in Lindau , Germany, where he did much of his research and where Wankel R & D is located (though some place his death in Heidelberg).

Animal Welfare

Dr. Wankel had a strong impulse towards animal welfare . Since 1972 there is the Felix Wankel Tierschutz Forschungspreis: Prize for Protection of Animals in Research, maximum DM 50,000 for outstanding research to limit, replace, or as much as possible discontinue experiments with live animals. It may also be awarded for research that promotes the concept of animal protection. Write to Dekanat der Tierärztlichen Fakultät der Ludwig Maximilians Universität, Veterinästraße 13, 80539 München, Germany, Tel: 089-2180 2512.

In 1994 or 95 it was won by Dr. Markus Stauffacher at the Institute for Laboratory Animals at the University of Zurich, for work in the area of animal husbandry. In 1997 it was won by Kuck and Winter for an "Alternative Method Myograph" for physiological instruction. In 1978, the International Society for Livestock Husbandry (Internationale Gesellschaft für Nutztierhaltung - IGN) was created from the suggestion of Dr.h.c. Felix Wankel and with his support.

A quotation from Felix Wankel: "Wenn jemand Tierschlachtung und Tierversuch noch völlig unbeeindruckt bejaht, dann ist in seiner menschlichen Entwicklung ein Stückchen Steinzeit noch nicht überwunden". "If someone slaughtering animals or doing bio-assay is still completely unimpressed, then in human development a bit of Stone Age is not yet overcome."

Felix Wankel wurde am 13. August 1902 in Lahr geboren und starb am 9. Oktober 1988 in Lindau. Er war Ingenieur und entwickelte den Wankel Drehmotor. Dieser unterschied sich durch die Präsenz eines umkreisenden Drehzylinders in der Form eines gekrümmten gleichseitigen Dreiecks. Die Vorteile in der Maschine bestanden in Leichtigkeit, wenigen beweglichen Teilen, Kompaktheit, geringen Anfangskosten und hoher Leistung. 1954 entwickelte Wankel den ersten Drehkolbenmotor, der von .

How a Wankel Rotary Engine Works

 You don't have to look too hard to notice that the functions of the intake, compression, power and exhaust strokes are present in the Wankel as one of its rotors goes through a single revolution.

And because the Wankel does all this in one revolution, not in two complete turns as happens in most other car engines, it's also reminiscent of the two-stroke engines you're apt to find in your lawn mower or your boat's outboard motor. In fact, the Wankel sounds very much like these conventional twostrokers as it runs.

What's more, there's nothing really unusual about the operating hardware that works with the rotary engine. It's fed by either a carburetor or a fuel injection system, depending upon emissions requirements in demand at the time it was built. It fires the fuel-air mixture by means of spark plugs. It gets rid of burned gases through an exhaust system. And it propels the car by means of a rotating output shaft and a conventional powertrain, just like other automotive engines.


Now that we've somewhat diffused the mystery of the rotary engine, let's look inside one and discover what makes it tick. Here's what we'll see.

Figure I puts us squarely in front of the heart of the engine's interior, looking rearward. The bulgy triangle-shaped part with a geared hole in its center is one of the rotors that are standard in every current Mazda Wankel engine.

As the rotor turns clockwise (in the illustration) within its housing, the smaller gear that mates with the rotor gear is pulled along by the rotor gear teeth, also in a clockwise direction. And because it's attached firmly to the output shaft, rotation of that smaller gear turns the shaft. This is how the Wankel sends rotating power (or torque, to give it thecorrect name) to turn shafts, gears, U-joints and what-have-you on itís way to the driving wheels of the car.

In addition to the rotor and the output shaft, the rotary engine's key components in the power-production fonnula are the spark plugs and the intake and exhaust ports. We've already covered how altering the size and/or shape of the ports can significantly increase horsepower


Okay, now we're going to fire up this powerplant and see what happens in slow motion. We'll begin the show by looking at the illustration "A" of Figure 2.

Notice that the rotor flank (the almost-flat side of the rotor) at the left side of illustration "A" is starting to create a working chamber with the inside curved wall of the housing. This chamber is taking in a charge of the fuel-air mixture from the open intake port in response to the increasing volume as the rotor turns clockwise.

While the rotor continues to turn in illustration "B", the expanding chamber draws in still more of the fuel-air mixture until at "C" the trailing edge of the rotor closes off the intake port to seal the fuel-air mixture in the chamber.

Continued clockwise rotation as the rotor moves toward Top Dead Center creates compression.

At D the spark plugs fire. Two spark plugs are used for each rotor to help assure proper combustion and reduce emissions within the Wankel's long, thin combustion area.

Expansion of the burning fuel-air mixture, as shown in "F", creates pressure in this chamber, forcing the rotor to turn. Rotation of the rotor causes it to transmit torque to the eccentric shaft. This (expanding charge) principle is the same for all internal combustion engines.

At "G", the leading apex seal passes the exhaust port and burnt gasses escape out the port and through the car's exhaust system.

At "H", the last remnants of the exhaust gases are being carried by their own momentum out the exhaust port even as the leading apex seal is uncovering the intake port to accept another fuel-air charge. In practice, this technique is the same as providing a slight amount of valve overlap for more efficient scavenging of exhaust gases with a reciprocating piston engine. And as with a piston engine, the resulting dilution of the fuel-air mixture helps to keep emission levels of unburned hydrocarbons and oxides of nitrogen under control.


Now let's pick up a point that fell by the wayside in our necessarily brief overview. Perhaps you may have noticed that some illustrations in this series are almost deadringers for others in the sequence of events. No, we didn't get lazy with the illustrations. The reason for this is that there were two more chambers sharing the rotor and housing with the chamber we were watching. In turn, these two rotor chambers were going through the same steps as the one we watched, only later. While the first chamber was pushing out exhaust gases, for example, the fuel-air mixture with the second chamber was being ignited and the third chamber was getting a fresh charge of fuel and air.

In effect, each rotor acts like three pistons of a conventional reciprocating engine. With the two-rotor Wankel that's a Mazda standard, it's like having a conventional six under the hood. And you know how smoothly they can run.

Figure 1: Parts of the Rotary engine

Figure 2: Combustion cycle of the Rotary engine

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