In 1939, at the Berlin Auto Show, Karl Schlör showed a prototype aerodynamic rear-engine car called the Schlörwagen (nicknamed “Göttinger Egg” or “Pillbug”). He redesigned the exterior by setting the windows flush with the shell for better airflow and extending the body over the front wheels.
According to the Schlörwagen, it achieved a top speed of 135 mph (84 mph) – 20 km/h (12 mph) faster than the Mercedes – and consumed 8 liters of fuel per 100 kilometers – 20 and 40 percent less fuel than the Mercedes. Karl Schlör estimates that the vehicle could reach a speed of 146 km/h (90 mph).
At the Berlin Auto Show in 1939, the car was unveiled to the public for the first time. However, the people saw it as ugly despite receiving a lot of publicity. When World War II began, the project was shelved, and mass production never took place. There is no trace of the prototype, and it was never put into production.