The term “Kammback” refers to an automotive body style with a roofline that tapers downward toward the car’s rear before being cut off abruptly. Early studies found that a car with a teardrop shape yielded the best aerodynamics, but it necessitated a body that was impractically long. Further experimentation showed that the end of the teardrop could be lopped off without a significant drag increase; the vertical surface created turbulence that effectively filled in for the missing tail, allowing air from the top of the car to flow smoothly.
Origin of the Kammback
Several designers and engineers worked on the truncated-teardrop shape. In 1938, German engineer and aerodynamicist Wunibald Kamm designed a prototype BMW 328 with such a body, intended for entry in the 1940 Mille Miglia. BMW called the car the Kamm Coupe, and the body style became known as the Kamm-tail, or Kammback. The original 328 Kamm Coupe was lost, but BMW created a replica in 2010.
Kammbacks have been used for several automobiles since the 1940s, primarily for European cars where hatchbacks are a more common body style. However, one of the earliest production cars to use a Kammback design was the 1949 Nash Airflyte. Among the most common Kammbacks you’ll see today are the second- and third-generation Toyota Prius. The first-generation Datsun Z cars, Audi’s A7, today’s Hyundai Ioniq, and Mustangs from the early 1970s all use a Kammback design.
Cars Called Kammback That Weren’t Actually Kammbacks
General Motors built some of the best-known Kammbacks-that-weren’t-Kammbacks. The 1970 Camaro Kammback was a two-door wagon/shooting brake based on the Camaro, and while the design did yield aerodynamic benefits, it was not a true Kammback. GM returned to this theme a decade-and-a-half later with the 1985 Pontiac Trans Am Kammback, another shooting brake concept that was not a genuine Kammback.
According to designer John Houlihan, the Camaro Kammback was a significant influence on the Chevrolet Vega two-door wagon, which was marketed as the Vega Kammback. While the Vega wagon does have a very slight taper to the roofline, it, like the Camaro concept, is not a true Kammback because it lacks a deeply sloped roofline and the vertical cut-off at the tail.
In 1980, AMC took its venerable Gremlin, stuck it on a four-wheel-drive chassis, and called it the AMC Eagle Kammback. But it was more false advertising: While the back is indeed sloped, the incline starts too far rearward, is too steeply raked, and there’s no vertical cut-off. This Kammback isn’t a Kammback.
Kammbacks are difficult shapes to design; while they yield great aerodynamic benefit, they are terrible for rear-seat headroom. As the majority of vehicles are produced in a single body style—one with four doors—a tall roofline is a necessity, which is why few cars are designed as Kammbacks.
Hybrids like the Hyundai Ioniq and Toyota Prius still use a Kammback shape for its fuel-saving aerodynamic properties. Proof that it works is found when comparing the fuel economy of the third-generation Prius to the Prius C: The C is smaller and lighter, but its traditional hatchback shape is less aerodynamic than the larger Kammback Prius.
BMW and Mercedes SUV “coupes” like the X4, X6, and GLC and GLE coupes use a sort-of Kammback shape, though their tail ends have a few more lumps and bumps than a proper Kammback ought to have.
Kammbacks In the Future
With two-box SUVs dominating the family-car market, we are unlikely to see a resurgence of mainstream Kammbacks, though we are more likely to see them in the performance segment. Slick “four-door coupes” are increasingly popular, and we’ve seen several such cars adopt a Kammback shape, including the Audi A7/S7/RS7 family and the Kia Stinger. The Kammback’s beauty is that it is both functional and attractive, and as a result, we’ll take as many as we can get. To see and learn more about Kammback’s, subscribe now to the MotorTrend App and check out this episode of Junkyard Gold.