Wunibald Kamm (April 26, 1893 in Basel – October 11, 1966 in Stuttgart) was an automobile designer, engineer, and aerodynamicist. He is best known for his breakthrough in reducing car turbulence at high speeds; the style of car bodywork based on his research has come to be known as a Kammback or a Kamm-tail.
One goal of automotive aerodynamics is to reduce the air turbulence, or drag, caused by the shape of the automobile. Aerodynamic drag may be reduced either by reduction of frontal area or by reduction of drag coefficient. In bodies such as automobiles and airships, drag decreases after the rear of a car's cross-sectional area is reduced to fifty percent of the car's maximum cross section; "the best position is nearer 45 per cent of the length, and ... to have this maximum cross- section nearer the rear end than the front, and its drag has proved even less". There are other aspects of the car's design such as keeping the flow of air attached to the body far to the back of the car as possible to minimize pressure drag (the Bernoulli relationship). A design with less drag means higher efficiency and an increased maximum velocity, given the same powertrain.
German Professor, Wunibald Kamm worked with aerodynamics engineer Baron Reinhard von Koenig-Fachsenfeld. They developed a design with a smooth roofline and a taper in the automobile's body that is suddenly chopped off at the rear end. This design makes the air flow act as if a full tapered "tail" was present on the vehicle. A full size prototype was developed in 1938. It was a four-door sedan featuring a sharply truncated rear end. The test car represented a compromise between a low air resistance and practicality in the automobile's size and shape.
In the 1920s, Kamm worked he worked for Daimler designing engineering race car engines. Thereafter, a prototype, namely the Kamm “SHW Wagen” incorporated principles that have become standard parts of the car engineering toolbox. He paid particular attention to the suspension and minimizing vehicle weight. These improvements included extreme low weight design, an aluminum semi-monocoque body, front wheel drive, boxer-style engines (horizontally opposed cylinders), independent suspension on all wheels, and coil springs mated to hydraulic shock absorbers. His comprehensive approach to automotive engineering and design presaged the concept of "Mechatronics," a word that did not come into existence until 1971.
Established in 1930, the Research Institute of Automotive Engineering and Vehicle Engines located near Stuttgart (German: Forschungsinstitut für Kraftfahrwesen und Fahrzeugmotoren Stuttgart - FKFS) was called the "Kamm-Institut" after its founder and long-time director.
He is a member of the Automotive Hall of Fame. He did pioneering work in aerodynamics, driving dynamics, tire technology, minimalist construction techniques, engine combustion efficiency. Wind tunnels were an effectively applied technology, and he "built the first full-scale wind tunnel for motor vehicles." "Dr. Kamm, even today, and perhaps even more so because of his foresight, is considered one of the greatest researchers in automotive engineering." His work on turbulence is considered to have been "breakthrough" and fundamental.
He came to the United States of American as one of the first hundred German scientists stationed at the Dayton, Ohio Wright-Patterson Air Force Base. there he was as a consulting engineer until 1953. That year, he went as a professor to the Stevens Institute of Technology in Hoboken, New Jersey. For three years beginning in 1955 he was head of Mechanical Engineering at the Battelle Memorial Institute in Frankfurt, Germany.
The first "Kamm coupe"
In late summer of 1938, BMW tested a prototype of the so-called "Kamm-Coupe" based on their 328 chassis. It had a drag coefficient of only 0.25 compared to the great 1940 Mille Miglia winning BMW 328 Touring Coupe with drag coefficient 0.35. This automaker's naming of its coupé model appears to be the earliest use of "Kamm" to publicly describe an automobile body incorporating the Koenig-Fachsenfeld's design patent.
Kammback named production cars (USA)
- AMC Gremlin and AMC Eagle—The design was not to improve streamlining, but to improve space efficiency.
- Chevrolet Vega—The station wagon model had more taper than the Gremlin, but not enough to gain aero-effects.
The Kammback "cut off tail" design continues to be popular. Most often, however, it only insinuates streamlining when used in production cars. It is then only a design trick to make the vehicle look "fast".
Dr. Kamm's wind cheating principle is used in a variety of popular mass-market vehicles, supercars, highly efficient hybrid powered cars, as well as outright racecars.
- Institution of Mechanical Engineers (1970). Journal of Automotive Engineering, Volume 1. Institution of Mechanical Engineers (Great Britain). Automobile Division. p. 18.
- SAE transactions 27. Society of Automotive Engineers. 1932. p. 118.
- Barnard, R. H. (2001). Road vehicle aerodynamic design: an introduction. St Albans: MechAero. p. 43. ISBN 978-0-9540734-0-4.
- "Wunibald I.E. Kamm". Automotive Hall of Fame. Retrieved May 29, 2014.
- Hirschel, Ernst-Heinrich; Prem, Horst; Madelung, Gero (2003). Aeronautical research in Germany: from Lilienthal until today (Print) 147. New York: Springer-Verlag. p. 221. ISBN 978-3-540-40645-7. Retrieved 2 September 2010.
- "History (1930-1945)". Forschungsinstitut für Kraftfahrwesen und Fahrzeugmotoren Stuttgart. Retrieved 3 September 2010.
- Ihrig, Ron (December 3, 2004). "Part 3: Production, Physics, Politics – Only the Strong Survive". Car Design News. German Design History. Car Design News cardesignnews.com. Retrieved September 6, 2007.
- Robinson, Peter; LOCI Ltd (2002). "The Pininfarina 1800". LOCI Ltd. Retrieved May 29, 2014. - an explicitly Kamm-influenced design which informed the Citroën CX and Rover SD1
- Ziemnowicz, Christopher (2004). "The Origin of the Kammback Design". Retrieved May 29, 2014. archived from the original at Wayback Machine Internet Archive
- BMW Designers Wunibald Kamm on the website with overview of automotive designers working for BMW.