# Kammback
A **Kammback** is an automotive body style in which the roofline tapers downward toward the rear of the car and then ends in an abrupt, roughly vertical cut-off, a shape named after the German aerodynamicist Wunibald Kamm. The design applies a finding from 1930s aerodynamic research: a full teardrop-shaped car body gives the lowest drag but is impractically long, and the tail can be truncated with only a modest drag penalty because the vertical rear surface creates a turbulent wake that acts like the missing tail, letting air from the top of the car flow smoothly past[1](https://www.motortrend.com/features/what-is-a-kammback).
| Key fact | Detail |
|---|---|
| Definition | Roofline tapers toward the rear and is cut off abruptly at a vertical surface (the Kamm-tail or Kamm-Heck)[1](https://www.motortrend.com/features/what-is-a-kammback) |
| Origin | Wunibald Kamm received a 1936 patent for a streamlined car body with a cut-off rear; he had studied vehicle streamlining in a small wind tunnel at 55 m/s in 1932[2](https://www.deutsche-biographie.de/sfz39669.html) |
| Truncation rule | Optimum drag coefficients are typically achieved when the car's cross-sectional area at the rear is about 50% of its maximum cross-section, followed by a sudden truncation of the tail[3](https://catchmentsandcreeks.com.au/docs/Race-Car-Aerodynamics-screen.pdf) |
| Landmark prototype | BMW 328 Kamm Coupé (1938–39), model-measured Cd of about 0.25 versus about 0.35 for the comparable Touring Coupé, top speed 230 km/h[4](https://www.press.bmwgroup.com/canada/article/detail/T0079889EN/a-victory-of-passion-and-precision-70-years-ago-bmw-won-the-mille-miglia?language=en) |
| Early production use | The 1949 Nash Airflyte was among the earliest production cars with a Kammback design[1](https://www.motortrend.com/features/what-is-a-kammback) |
| Modern examples | Second- and third-generation Toyota Prius, Honda Insight (Cd 0.25), Audi A7, Hyundai Ioniq, and early-1970s Ford Mustangs[1](https://www.motortrend.com/features/what-is-a-kammback) • [5](https://hondanews.eu/eu/en/cars/media/pressreleases/34323/insight-2000) |
| Trade-off | The shape yields aerodynamic benefit but is poor for rear-seat headroom, which limits its use in four-door vehicles[1](https://www.motortrend.com/features/what-is-a-kammback) |
## Aerodynamic principle
The rear of a car is a bluff body, and most of its aerodynamic drag comes from the pressure difference between the front and rear created by the wake[6](https://research.chalmers.se/en/publication/176766). A long, gradually tapering tail keeps flow attached and minimizes this pressure drag, but the length needed is impractical for a road car. Kamm's solution was to taper the body until its cross-section had fallen to roughly half of the maximum, then cut it off vertically. Because the cross-section behind the separation is already diminished, the wake is smaller and the increase in drag is minimized[3](https://catchmentsandcreeks.com.au/docs/Race-Car-Aerodynamics-screen.pdf) • [7](https://s3.eu-central-1.amazonaws.com/eu-st01.ext.exlibrisgroup.com/27UOJ_INST/storage/alma/7A/27/1D/15/9B/91/17/B5/6A/80/37/34/8C/67/A2/E0/uj_11199%2BCONTENT1%2BCONTENT1.2.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAJUYRSPBSIJGGDX6A%2F20260331%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260331T093604Z&X-Amz-Expires=119&X-Amz-Signature=e314de87724fb7018f91d41e98936a5b86e7d967fb57cd7b3c663280526d9400&X-Amz-SignedHeaders=host&response-content-type=application%2Fpdf). A 1939 assessment of the era's work credited the Kamm tail design with drag coefficients of 0.25 to 0.3[8](https://scholarworks.indianapolis.iu.edu/server/api/core/bitstreams/3f680fde-f103-4d8e-814a-933221d560cd/content).
The popular interpretation of the Kamm back, that a truncated tail has almost the same drag as a fully streamlined one, holds only for some near-axisymmetric bodies. A 2020 SAE review by Jeff Howell, Eleanor Rajaratnam, and Martin Passmore of Loughborough University found that for many more car-like shapes the drag reduction from an elongated tail varies almost linearly with the reduction in cross-sectional area, so a longer tail keeps helping[9](https://saemobilus.sae.org/papers/streamlined-tails-effects-truncation-aerodynamic-drag-2020-01-0673). Kamm's own research also showed that the low drag of slender-tailed cars is achieved only when flow around the front of the car remains attached; separation caused by a steep windscreen increases drag dramatically and disturbs flow over the rest of the car[7](https://s3.eu-central-1.amazonaws.com/eu-st01.ext.exlibrisgroup.com/27UOJ_INST/storage/alma/7A/27/1D/15/9B/91/17/B5/6A/80/37/34/8C/67/A2/E0/uj_11199%2BCONTENT1%2BCONTENT1.2.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAJUYRSPBSIJGGDX6A%2F20260331%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260331T093604Z&X-Amz-Expires=119&X-Amz-Signature=e314de87724fb7018f91d41e98936a5b86e7d967fb57cd7b3c663280526d9400&X-Amz-SignedHeaders=host&response-content-type=application%2Fpdf).
## Wunibald Kamm and the BMW Kamm Coupé
**Wunibald Kamm** (1893–1966) became professor of automobile engineering at the Technical University of Stuttgart and in 1930 founded the Forschungsinstitut für Kraftfahrwesen und Fahrzeugmotoren (FKFS) in Stuttgart-Untertürkheim, a research foundation supported by the state of Württemberg and the automotive industry[2](https://www.deutsche-biographie.de/sfz39669.html) • [10](https://carsite.co.za/developments-in-aerodynamics). In 1932 he studied vehicle handling and streamlined bodies in a small wind tunnel at 55 m/s airspeed, supplementing the results with road tests, and in 1936 he received a patent on a streamlined car body with a cut-off rear[2](https://www.deutsche-biographie.de/sfz39669.html). Some accounts give partial credit for the design to the aerodynamicist R. V. Koenig-Fachsenfeld, even though Kamm had published a paper showing the design in 1934[7](https://s3.eu-central-1.amazonaws.com/eu-st01.ext.exlibrisgroup.com/27UOJ_INST/storage/alma/7A/27/1D/15/9B/91/17/B5/6A/80/37/34/8C/67/A2/E0/uj_11199%2BCONTENT1%2BCONTENT1.2.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAJUYRSPBSIJGGDX6A%2F20260331%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260331T093604Z&X-Amz-Expires=119&X-Amz-Signature=e314de87724fb7018f91d41e98936a5b86e7d967fb57cd7b3c663280526d9400&X-Amz-SignedHeaders=host&response-content-type=application%2Fpdf).
The best-known early application was a racing prototype. After wind tunnel testing showed that an earlier streamlined body did not fit the BMW 328 chassis, BMW's design department under Wilhelm Meyerhuber drew a new body under project number AM 1008, with the chassis extended by 20 centimeters for straight-line stability and an Elektron space frame weighing just 30 kilograms[4](https://www.press.bmwgroup.com/canada/article/detail/T0079889EN/a-victory-of-passion-and-precision-70-years-ago-bmw-won-the-mille-miglia?language=en). The resulting Kamm Coupé was significantly larger than the comparable Touring Coupé yet 20 kilograms lighter, and it proved far less sensitive to side winds. Its model-measured drag coefficient of about 0.25 was well below the Touring Coupé's roughly 0.35, and the car reached 230 km/h in testing on the Munich to Salzburg autobahn in late summer 1939[4](https://www.press.bmwgroup.com/canada/article/detail/T0079889EN/a-victory-of-passion-and-precision-70-years-ago-bmw-won-the-mille-miglia?language=en). The outbreak of war ended its racing prospects, the original car was lost, and BMW built a replica in 2010[1](https://www.motortrend.com/features/what-is-a-kammback).
## Production and near-production use
Kammbacks have appeared on automobiles since the 1940s, primarily on European cars where hatchbacks are a common body style. One of the earliest production cars to use the design was the 1949 Nash Airflyte[1](https://www.motortrend.com/features/what-is-a-kammback). Later examples frequently cited as true to the concept include the first-generation Datsun Z cars, the [Audi A7](https://www.edgepedia.org/audi-a7), the [Hyundai Ioniq](https://www.edgepedia.org/hyundai-ioniq), and Ford Mustangs from the early 1970s[1](https://www.motortrend.com/features/what-is-a-kammback).
The design found a natural home in hybrids, where low drag directly improves fuel economy. The [Honda Insight](https://www.edgepedia.org/honda-insight) of 2000 combined a long tapered roof with a tail designed to reduce the area of air separation, achieving a drag coefficient of 0.25, which Honda described as the best aerodynamic characteristic in a mass production car at the time[5](https://hondanews.eu/eu/en/cars/media/pressreleases/34323/insight-2000). The second- and third-generation [Toyota Prius](https://www.edgepedia.org/toyota-prius) are among the most common Kammbacks on the road; the second-generation car's "triangle silhouette," introduced in 2003, improved aerodynamics while establishing the model's distinctive styling[1](https://www.motortrend.com/features/what-is-a-kammback) • [11](https://global.toyota/en/prius20th/evolution/?trk=article-ssr-frontend-pulse_little-text-block).
## Kammbacks in name only
Several well-known vehicles carried the Kammback name without having a true Kammback shape. The 1970 Chevrolet Camaro Kammback was a two-door wagon or [shooting brake](https://www.edgepedia.org/shooting-brake) based on the Camaro; although the design yielded aerodynamic benefits, it was not a genuine Kammback. GM returned to the theme with the 1985 Pontiac Trans Am Kammback, another shooting brake concept. The [Chevrolet Vega](https://www.edgepedia.org/chevrolet-vega) two-door wagon, marketed as the Vega Kammback and influenced by the Camaro concept according to designer John Houlihan, has only a slight roofline taper and lacks the deeply sloped roof and vertical cut-off. In 1980 AMC put its Gremlin on a four-wheel-drive chassis and called it the AMC Eagle Kammback, but the rear slope starts too far rearward, is too steeply raked, and has no vertical cut-off[1](https://www.motortrend.com/features/what-is-a-kammback).
The loose usage has a history: in 1970s North America the style was applied to the Chevrolet Vega wagon and the [AMC Hornet](https://www.edgepedia.org/amc-hornet) wagon, leading many people to treat "Kammback" as another word for station wagon or hatchback even though it refers to the specific aerodynamic design of the rear of the car[12](https://automobile.fandom.com/wiki/Car_body_style).
## Why the shape is uncommon
Kammbacks are difficult shapes to design. They deliver aerodynamic benefit but are poor for rear-seat headroom, and because most vehicles are produced in a single four-door body style that requires a tall roofline, few cars are designed as Kammbacks. Hybrids such as the Hyundai Ioniq and Toyota Prius continue to use the shape for its fuel-saving properties; [Motor Trend](https://www.edgepedia.org/motor-trend) points to the comparison between the third-generation Prius and the smaller, lighter Prius C, whose traditional hatchback shape is less aerodynamic than the larger Kammback Prius[1](https://www.motortrend.com/features/what-is-a-kammback).
## References
1. [What Is a Kammback Car? Motor Trend](https://www.motortrend.com/features/what-is-a-kammback)
2. [Kamm, Wunibald, Deutsche Biographie](https://www.deutsche-biographie.de/sfz39669.html)
3. [An Introduction to Race Car Aerodynamics](https://catchmentsandcreeks.com.au/docs/Race-Car-Aerodynamics-screen.pdf)
4. [A victory of passion and precision. 70 years ago BMW won the Mille Miglia, BMW Group Press](https://www.press.bmwgroup.com/canada/article/detail/T0079889EN/a-victory-of-passion-and-precision-70-years-ago-bmw-won-the-mille-miglia?language=en)
5. [Insight 2000, Honda News Europe](https://hondanews.eu/eu/en/cars/media/pressreleases/34323/insight-2000)
6. [Analysis of the Base Wake on Passenger Vehicles, Chalmers University](https://research.chalmers.se/en/publication/176766)
7. [Adaptive Automotive Aerodynamics (2013)](https://s3.eu-central-1.amazonaws.com/eu-st01.ext.exlibrisgroup.com/27UOJ_INST/storage/alma/7A/27/1D/15/9B/91/17/B5/6A/80/37/34/8C/67/A2/E0/uj_11199%2BCONTENT1%2BCONTENT1.2.pdf?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAJUYRSPBSIJGGDX6A%2F20260331%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260331T093604Z&X-Amz-Expires=119&X-Amz-Signature=e314de87724fb7018f91d41e98936a5b86e7d967fb57cd7b3c663280526d9400&X-Amz-SignedHeaders=host&response-content-type=application%2Fpdf)
8. [Advances in Vehicular Aerodynamics, IUPUI](https://scholarworks.indianapolis.iu.edu/server/api/core/bitstreams/3f680fde-f103-4d8e-814a-933221d560cd/content)
9. [Howell, J., Rajaratnam, E., Passmore, M. (2020). Streamlined Tails - The Effects of Truncation on Aerodynamic Drag, SAE 2020-01-0673](https://saemobilus.sae.org/papers/streamlined-tails-effects-truncation-aerodynamic-drag-2020-01-0673)
10. [Developments in aerodynamics](https://carsite.co.za/developments-in-aerodynamics)
11. [The evolution of the Prius, Toyota Motor Corporation](https://global.toyota/en/prius20th/evolution/?trk=article-ssr-frontend-pulse_little-text-block)
12. [Car body style, Autopedia](https://automobile.fandom.com/wiki/Car_body_style)
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*Topic: Encyclopedia › Technology and the built world › Transport and spaceflight › Road transport › Automobiles › Car body styles and types*
*Initially written Sep 17, 2026 · Reviewed: Oct 15, 2026 · Edited: Oct 15, 2026 · Last review: Oct 15, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license