Designing a spin for the tail end of things

Wed, Aug 8, 2007, 01:00

PastImperfect: Wunibald Kamm and the 'K-Tail'The name of Wunibald Kamm is well-known in automotive circles as the designer of a "cut-off" vehicle tail - the so-called "K-Tail" - which dramatically reduced the effort needed to move cars through the air. But strangely while Kamm did play a role in developing the K-Tail, it was another man whose name also began with "K" who actually patented the idea.

While Kamm was interested in streamlining, his interest only extended to times when he could incorporate it into other work, such as observation balloons, supercharged car engines, aircraft undercarriages and high-altitude aero engines.

Born in Basel, Switzerland in April 1893, Kamm's family moved to Cannstatt in 1901 where the young Kamm was in the same school class as Daimler's youngest son, Gottlieb. Entering Germany's army in 1914, he studied the mechanics and stability of captive observation balloons, suggesting improvements for which he was granted a patent.

One of his first roles after the end of the war was in sorting out chronic vibrations in the engines of the Graf Zeppelin, while in the second World War, he worked on everything from propeller design to flutter in aircraft tail-wheels. Between the wars, Kamm worked as an engineer for Daimler under Ferdinand Porsche.

It was towards the end of his Daimler period that Kamm produced the first of his pioneering small car designs. The SHW - named after the Schwäbischen Hütten Werke, which financed its construction - was a 4/5 seater of light weight with low wind resistance and front-wheel-drive.

Freiherr Reinhard Koenig-Fachsenfeld, a pioneer German aerodynamicist, was working on the design of an aerodynamic body for a bus. He discovered that longer, taller bodies which were then cut off with rounded edges achieved significantly better aerodynamic figures. Koenig-Fachsenfeld patented his idea while at around the same time Kamm published a text proposing similar solutions for low-drag vehicles.

Several prototypes - the K-cars - were built, incorporating this thinking. After the war he moved to the US before returning to Germany in 1955, joining the Battelle Institute, where he continued to work until his retirement.

Kamm died of cancer in 1966 leaving his name on automobile rear section design in the form of the "K-Tail" and the "Kamm" both of which are little understood and even today, seldom correctly applied.