Kammback
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A Kammback is a car body style influenced by the research of the German aerodynamicist Wunibald Kamm in the 1930s.
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[edit] Aerodynamics
Kamm showed that a better drag-reducing tail end design for a car is one that tapers and is then cut off abruptly.
The point at which this must happen, in order for the design to be a true Kammback, is controversial. A popular definition is that the cut-off should occur where the cross sectional area is approximately 50% of the car's maximum cross-section. Thus a minivan is not a Kammback.
Prior to Kamm's thesis, a teardrop shape that tapered smoothly to a point was considered optimal. Kamm showed that an abbreviated teardrop actually worked better; the air still flowed as if the entire teardrop were still there, but without the surface drag of the long point.
Usage of the term has fallen off as Kamm's principles have become more generally accepted.
[edit] Kammback cars
Many cars have had a Kamm tail, especially sports cars, like 1940 BMW 328 "Mille Miglia" Kamm, the 1968 Ferrari Dino and 1970 Citroën SM, as well as cars for ordinary motorists, like the 1970 Citroën GS and the 1970 AMC Gremlin (which fails the 50% test by having a sharp cut from roof to base of car).
American car manufacturers have described certain models as Kammbacks with greater or lesser degrees of accuracy. In many cases, it has simply been used as a substitute for "station wagon" or "hatchback".
[edit] General Motors
General Motors produced a 2-door station wagon version of the Chevrolet Vega in the 1970s that was called a Kammback, although it lacked appreciable rear-end taper before the cut-off rear and thus cannot accurately be said to follow Kamm's design.
In 1978, a Kammback version of the Pontiac Firebird was considered with prototypes built and shown on the auto show circuit. In many respects similar to what the British would call a shooting brake (a station wagon version of a sporting coupé), this "Type K" did not have a tailgate but rather lifting side windows for access to the cargo area. Costs eventually killed the project, but from 1980 replica aftermarket conversions were available for a short time from an independent manufacturer. In 1986 Chevrolet built two similar Camaros, but again the concept did not reach production.
[edit] American Motors
AMC stylist Richard A. Teague became a fan of this truncated somewhat-"Kammback" style in the late 1960s as he considered simple ways of adding to AMC's model range. He came up with the idea of truncating a larger car to make a smaller, enabling the two cars to share a lot of common tooling. This concept first came to the public as the AMX, a cut-down 2-seat version of the 4-seat Javelin coupé, although this shared the Javelin's rear and was not a Kammback. A still further cut-down concept car with a Kammback tail, the AMX GT, was shown in 1968, but never entered production. Instead, Teague adapted the concept to AMC's next car, the compact Hornet, to produce the Gremlin subcompact in 1970. The Gremlin kept the Kammback style until the end of the model line in 1977; then, the rear sail panel was opened up with a larger rear window, along with other refinements and the car was rebadged as the Spirit sedan. The Spirit sedan continued through the 1982 model; in 1981 and 1982, a 4WD spinoff found extra life as the AMC Eagle Kammback.
[edit] Others
In 1985, the Fiat Group introduced a rather luxurious small town car named the Y10, initially under the Autobianchi brand and later badged as a Lancia, featuring an abrupt tail which, combined with its clean lines and bodywork detailing, gave a drag coefficient of 0.30, resulting in excellent fuel economy.
Other Kammback cars have included the Alfa Romeo GTV, the Citroën CX, the Maserati Khamsin, and the Volvo S60. The feature is also visible on hybrid cars designed for extremely high gas mileage, such as the second-generation Toyota Prius and the Honda Insight.
One of the most well-known examples of the use of the Kammback is the Alfa Romeo Spider. When the Spider was first introduced as the Duetto in 1966, it had a smoothly rounded tail. In 1971 Alfa Romeo brought out a new edition of the Spider. The new car's styling was almost identical to the Duetto except for the replacement of the "round-tail" with a so-called Kamm-tail. While Alfisti are still sharply divided in their preference for one version over the other, the supporters of the round-tail version have to concede the Kamm-tail's superior aerodynamics.
[edit] External links
- Article on the origins of Kammback design
- The Pininfarina 1800 - an explicitly Kamm-influenced design which informed the Citroën CX and Rover SD1
