On behalf of Auto Union AG, Chemnitz, Ferdinand Porsche developed a racing car in 1933, initially named Type P after him. The acceptance criteria were that the engine had to produce at least 250 hp. The car had to complete ten laps of the Avus without interruption and be capable of speeds of over 250 km/h on the straights. Work began in March 1933 and one year later Hans Stuck drove the finished car to a world record on the Berlin AVUS.
The racing car department was stationed at the Horch plant. The main reason for this: The necessary special machinery and highly qualified employees were available there. The racing car department initially consisted of 30 selected Horch employees, who were increased to around 50 over time.
Head of the racing department:
Willi Walb 1933 – 1935
Dr. Karl Feuereißen 1936 – 1939
Work on the Porsche design in the racing department began in March 1933; it was headed by Ferdinand Porsche, who was not an Auto Union employee but worked under contract.
The racing cars with the four rings on the bodywork were in use between 1934 and 1939. They competed for
the first time at the AVUS race in Berlin in 1934. Their bodies were silver right from the start, as the
aluminum of the outer skin was visible. Unlike all other competitors, the engine was positioned behind
the driver. Improved several times, the car had reached three stages of development by 1937:
1934 Type A: 295 hp
1935 Type B: 375 hp
1936 Type C: 520 hp
The basic design concept had not changed. The 16-cylinder V-engine was positioned in the middle of the car and behind the driver, thus anticipating the layout commonly used in racing car construction today by decades. With a displacement of six liters, the engine was so elastic - maximum torque 87 m/kg at 2500 rpm - that it made do with a four-speed gearbox. The Auto Union Type C was the most successful German Grand Prix racing car in 1936. It won three out of five Grand Prix races, half of the circuit races and all hill climbs in which the Auto Union took part. Over 30 world records were set with it. For the latter purpose in particular, intensive research and tests were also carried out in the wind tunnel in order to compensate for lower engine performance compared to the competition thanks to superior aerodynamics in the design of the bodywork. A speed of over 400 km/h was achieved for the first time on a normal road with such a car.
The successor model for the 1938 season, the Type D, was the car designed by racing engineer Eberan von Eberhorst for the new 3-liter formula. The 12-cylinder V-engine had three camshafts and achieved almost 500 hp in 1939 thanks to its lower piston weight, higher revs and twin supercharger. In contrast to the previous single-stage compressors, the cylinder could now be supercharged. As performance increased, so did the “thirst” of the engines: over 100 liters of the special fuel per 100 km ran through the carburetor.
The chassis was shorter than that of the Type C and the driver now sat right in the car's center of gravity. This was mainly due to the changed arrangement of the fuel tanks, which were no longer positioned in a U-shape behind the driver, but to the left and right of him. The rear axle, which was designed as a “de Dion axle”, was completely new.