The Schlörwagen German experimental vehicle from 1939 achieved a drag coefficient of 0.15 — making it dramatically more streamlined than a modern Prius:
Despite the lack of widespread wind tunnel testing and computer modeling, the 1920s and 1930s were a booming era for aerodynamics. The Czech Tatra 77, Chrysler Airflow, and Mercedes-Benz 540K Streamliner were impressive attempts to limit drag. These cars “conformed to the still fairly primitive understanding of aerodynamics (or streamlining) of the day, which approximates to making a car as close to a teardrop as possible,” says Sam Livingstone, director at Car Design Research and a judge for the World Car Awards. They looked a bit unusual but not loony, and they went into production, with varying levels of success.
The Schlörwagen was something else altogether. German engineer Karl Schlör, at the Aerodynamischen Versuchsanstalt (Aerodynamic Institute) in Göttingeng, started with a 38-horsepower Mercedes 170H. Inspired by the shape of airplane wings, he redesigned the exterior, setting the windows flush with the shell for cleaner airflow and extending the body over the front wheels. “Basically, the Schlörwagen is a wing on wheels,” says Andreas Dillmann, head of the Institute of Aerodynamics and Flow Technology at the German Aerospace Center (DLR), the successor to the Aerodynamischen Versuchsanstalt.
The result, unveiled at the 1939 International Motor Show in Berlin, was nicknamed the “Göttingen Egg.” It was nearly seven feet wide (just inches narrower than a first-generation Hummer) and had three-row seating for seven.
The changes worked: The 170H topped out at roughly 65 mph. The Schlörwagen, using the same engine, hit 84. And it needed just eight liters of fuel to cover 62 miles, a 20 to 35 percent improvement. The 0.15 drag coefficient is beaten only by modern designs of less practical cars like the General Motors EV1 and Volkswagen XL1.