Quote:
Ahead of its time, an experimental car was presented at the IAA Show in Berlin in the year 1939 – the Schlörwagen. Karl Schlör von Westhofen-Dirnstein (1911-1997), a German engineer developed this car at the research institute for aerodynamics (AVA) in Göttingen. His aim was to minimize the use of fuel by following the construction of aircraft wings for the car body. And he succeeded.
His prototype – with its nickname “Göttinger Ei” – built on the chassis of the Mercedes-Benz 170 H, had 20 % to 40 % less fuel consumption as its series model. The engineer even proclaimed a higher top-speed of around 30 % to 40 %. All of this was achieved by a streamlined body design which almost completely covered the wheels and – in contrast to later fuel efficient cars, aerodynamic experimental cars and record cars – which offered space for a complete family like today´s vans. The windows were fully integrated into an even surface of aluminium body, and a completely sealed underbody was also a big impact. The final result was a drag coefficient of 0.186 during contemporary measurements, but a later test with a replica model by Volkswagen technicians in the seventies resulted at a drag coefficient of 0.150. Some modern prototypes were better in the meantime, but they never offered the same passenger capacity. The drag coefficients are between 0.240 and 0.300 of today´s production cars with the same capacity.
Nevertheless, the Schlörwagen did not make it from prototype to series production because of two reasons: The shape and – again – the shape! With its low drag, the Schlörwagen reacted very heavy to side winds. This made it difficult or even dangerous to control the vehicle. Furthermore, people were not yet ready for a design like this. Even though, the internal values of the car were decisive, the body shape was considered as very strange and ugly for the times.
Even during the years of World War II, the Schlörwagen stayed an experimental car and was disassembled later. Karl Schlör unsuccessfully tried again to get the permission to rebuild his car, which was denied by the British Military Administration. Then, to Mr. Schlör’s disappointment, the chassis and the empty body were destroyed.
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There are details that I had not heard before. I think that side wind instability was also partly due to the weight of the rear engine, and to the early Porsche designed rear suspension and axle. An electric drivetrain would be much better in the Schlörwagen.
And a centerline fin on the back would probably offset the aero problem. The wind tunnel tuft test photo shows that the plan taper in the back was too steep, and there was lift / drag added as a result.
As good as the Schlörwagen was - it could be made even better.