Rumpler uncompromisingly applied the knowledge he had gained in aircraft design to an automobile, presenting his Tropfenwagen in 1921. The streamlined shape not only allowed a very low fuel consumption but also ensured optimum efficiency. The power output of the engine was converted into speed in the most efficient way possible. In addition, the new design certainly stirred up the industry but it did not stir up any dust. What may seem to be unimportant today was a key consideration at a time when many roads were simply gravel tracks. Tests in the Volkswagen wind tunnel confirmed this droplet-shaped prototype's low drag value in 1979. To this day, the Cd value of 0.28 which was measured can be considered to be exemplary.
400 km/h on the autobahn thanks to streamlining
In the 1930s, roads became better and vehicles became more powerful. Enthusiasm for motor racing grew throughout Europe. At racing circuits such as the Nürburgring or the Avus in Berlin, thousands of spectators cheered drivers on to faster and faster lap records. Optimized aerodynamic drag gave cars a decisive edge on the track. Strands of wool glued to the body provided new information in the wind tunnel. If the air flow remained constant, there was scarcely any movement of the strands. It is only when flow was interrupted that the strands waved backwards and forwards. In 1937, a further record was achieved. The Auto Union Type C racing car broke through the 400 km/h barrier not least because of its low drag value of 0.237. However, this was not on the racing circuit but on the Frankfurt-Heidelberg autobahn which had been closed for the purpose.
A Beetle sports model makes history in the wind tunnel
Soon afterwards, the automobile euphoria of engineers and industry was brought to an abrupt halt by the Second World War. Materials and machinery were needed for the war effort and were no longer available for fast vehicles on the autobahn.
During measurements made decades later in March 2003, a special VW Beetle sports version produced in 1947 thrilled the Volkswagen Research and Development team. In comparison with a standard Beetle produced at the same time, which had a rounded design intended mainly to ensure a spacious interior, the Volkhart V2 Sagitta not only looks but actually is more slippery. With a phenomenal drag coefficient of only about 0.22, the elegant sports coupe was a step ahead of the record racing cars of the 1930s.
The 1950s and 1960s
Beetle, tailfins and a new wind tunnel in Wolfsburg
However, the streamlined Sagitta was to remain an exception over the next few decades. In post-war Germany, cars mainly needed to be practical. The Beetle provided Germany with mobility and set off on its success story throughout the world. On the other side of the Atlantic, cars became larger and presented a more and more jagged appearance with giant tailfins. Thanks to cheap fuel and increasingly powerful engines, aerodynamic drag was of secondary importance, at least on production vehicles.
In Germany, Volkswagen took a ground-breaking step: 10 million Volkswagens had rolled off the production lines by 1965. According to the CEO at the time, Heinrich Nordhoff, the next 10 million were to be even better.