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Kammback on a 1969 Fiat 850 Coupe '69 Fiat 850 Coupe, example of Kammback.jpg
Kammback on a 1969 Fiat 850 Coupe

A Kammback—also known as "Kamm tail" or "K-tail"—is an automotive styling feature. The rear of the car slopes downwards before abruptly cutting off with a vertical surface. A Kammback minimizes aerodynamic drag while maintaining a practical shape for a vehicle.


The Kammback is named after German aero-dynamicist Wunibald Kamm for his work developing the design in the 1930s.

An efficient aerodynamic body shape of a vehicle improves its efficiency and fuel consumption. [1]

Some vehicles incorporate the kammback design based on aerodynamic principles, while some use a cut-off tail as a design or marketing feature.


1950 Nash Airflyte 1950 Nash Airflyte Ambassador Super (9351640857).jpg
1950 Nash Airflyte
1952 Borgward Hansa 2400 2007-09-08 02 Borgward Hansa 2400 (Ausschn, ret).jpg
1952 Borgward Hansa 2400

As the speed of cars increased during the 1920s and 1930s, designers observed and began to apply the principles of automotive aerodynamics. [2] As aerodynamic drag increases, more energy, and thus more fuel, are required to advance a vehicle. [3]

In 1922, Paul Jaray patented a car based on a tear-drop profile (i.e. a rounded nose and long tapering tail) to minimize the aerodynamic drag that is created at higher speeds. [4] [5] The streamliner vehicles of the mid 1930s—such as the Tatra 77, Chrysler Airflow and Lincoln-Zephyr—were designed according to these discoveries.

However, the long tail was not a practical shape for a car, so automotive designers sought other solutions. In 1935, German aircraft designer Georg Hans Madelung showed alternatives to minimize drag without a long tail. [6] In 1936, a similar theory was applied to cars after Baron Reinhard Koenig-Fachsenfeld developed a smooth roofline but with an abrupt end at a vertical surface, effective in achieving low amounts of drag similar to a streamlined body. [5] [7] [8] He worked on an aerodynamic design for a bus, and Koenig-Fachsenfeld patented the idea. [9] Koenig-Fachsenfeld worked with Wunibald Kamm at Stuttgart University, investigating vehicle shapes "provide a good compromise between everyday utility (e.g. vehicle length and interior dimensions) and an attractive drag coefficient". [5] [7] In addition to aerodynamic efficiency, Wunibald Kamm emphasized vehicle stability in his design. [7] He proved mathematically and empirically the effectiveness of the design. [10]

In 1938, Kamm produced a prototype using a Kammback, based on a BMW 328. [11] The Kammback, along with other aerodynamic modifications, gave the prototype a drag coefficient of 0.25. [12]

The earliest mass-produced cars using Kammback principles were the 1949–1951 Nash Airflyte in the United States and the 1952–1955 Borgward Hansa 2400 in Europe. [7]

Aerodynamic theory

The ideal shape to minimize drag is a "teardrop," a smooth airfoil-like shape, but it is not practical for road vehicles because of size constraints. [1] However, researchers including Kamm found that abruptly cutting off the tail resulted in a minimal increase in drag. [5] The reason for this is that a turbulent wake region forms behind the vertical surface at the rear of the car. This wake region mimics the effect of the tapered tail in that air in the free stream does not enter this region (avoiding boundary layer separation), therefore smooth airflow is maintained, minimizing drag. [11]

Kamm's design is based on the tail being truncated at the point where the cross section area is 50% of the car's maximum cross-section, [5] [13] which Kamm found represented a good compromise, as by that point the turbulence typical of flat-back vehicles had been mostly eliminated at typical speeds.

The Kamm tail presented a partial solution to the problem of aerodynamic lift, which was becoming severe as sports car racing speeds increased during the 1950s. The design paradigm of sloping the tail to reduce drag was carried to an extreme on cars such as the Cunningham C-5R, [14] resulting in an airfoil effect lifting the rear of the car at speed and so running the risk of instability or loss of control. The Kamm tail decreased the area of the lifting surface while creating a low-pressure zone underneath the tail.

Some studies showed the addition of a rear spoiler to a kammback design was not beneficial because the overall drag increased with the angles that were studied. [1]


1964-1969 Ford GT40 Ford GT40 (rear).jpg
1964-1969 Ford GT40
1974-1985 Citroen CX Citroen CX rear.jpg
1974-1985 Citroën CX
2000-2006 Honda Insight Honda-Insight-Rear.jpg
2000-2006 Honda Insight
2009-2015 Toyota Prius 2009 Toyota Prius (ZVW30R) liftback (2011-12-06) 02.jpg
2009-2015 Toyota Prius
2011 Audi A7 2011 Audi A7 (4G) 3.0 TFSI quattro hatchback (2016-01-07) 02.jpg
2011 Audi A7

In 1959, the Kamm tail came into use on full-body racing cars as an anti-lift measure, and within a few years would be used on virtually all such vehicles. The design had a resurgence in the early 2000s as a method to reduce fuel consumption in hybrid electric vehicles.

Several cars have been marketed as Kammbacks, despite the profile not adhering to aerodynamic philosophy of a Kammback. These models include the 1971–1977 Chevrolet Vega Kammback wagon, [15] the 1981–1982 AMC Eagle Kammback, [16] [17] [18] [19] the AMC AMX-GT and the Pontiac Firebird–based "Type K" concept cars. [20] [21] [22] [23] [24]

Some models that are marketed as "coupes"—such as BMW and Mercedes SUVs—"use a sort-of Kammback shape, though their tail ends have a few more lumps and bumps than a proper Kammback ought to have." [25]

Cars that have had a Kammback include:

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Coupe Closed two-door car body style with a permanently attached fixed roof which is shorter than a sedan

A coupe or coupé is a passenger car with a sloping or truncated rear roofline and two doors.

Grand tourer High-performance luxury car

A grand tourer (GT) is a type of sports car that is designed for high speed and long-distance driving, due to a combination of performance and luxury attributes. The most common format is a front-engine, rear-wheel-drive two-door coupé with either a two-seat or a 2+2 arrangement. Grand tourers are most often the coupé derivative of luxury saloons.


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Fastback Type of styling to rear car bodywork

A fastback is an automotive styling feature, defined by the rear of the car having a single slope from the roof to the tail. The kammback is a type of fastback style.

Grille (car)

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Wunibald Kamm 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.

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  34. Zenlea, David (8 February 2012). "First Drive: 2012 Toyota Prius C". Automobile. Retrieved 27 February 2016. ...featuring the same Kammback profile as the Prius and Prius V hatchbacks...
  35. Peters, Eric (22 May 2014). "2014 Honda Insight Review". National Motorists Association. Retrieved 27 February 2016. ...a Kammback layout, meaning the roof slopes gradually backward where it meets up with a fairly tall/vertical tail section.
  36. Halvorson, Bengt (20 February 2017). "2017 Hyundai Ioniq Hybrid". Car and Driver. Retrieved 19 June 2019. Despite the Ioniq’s wind-cheating Kamm-back profile, the styling is far more conservative than that of the polarizing Prius.
  37. Express, Auto (19 April 2021). "Ford Mustang Mach-E review - Practicality, comfort and boot space" . Retrieved 3 June 2021. ...Mach-E’s sloping coupe-style roof line...
  38. Turkus, Brandon (15 December 2020). "2021 Ford Mustang Mach-E First Drive Review: A Faster Horse" . Retrieved 3 June 2021. ...he black roof hides some of the mass from the front and sides, but viewed from behind, design sorcery can't obscure the height of the rear glass, the Kammback tail, or the rear fenders' girth...