It seems almost incredible today, but by 1936 the Auto Union racing cars were reaching speeds of up to 235mph on the long straights of the Avus circuit – truly, the birth of a legend

Driven by Hans Stuck, August Momberger and Hermann Prince zu Leiningen, this was their first appearance in competition. Technically, the Auto Union was intriguing because of its rear-mounted engine, and the Type A was designed to make the most of the new Grand Prix rules, which stipulated that the cars were limited to a total dry weight of 750kg – but the engines could be of any size and there was no restriction on the type of fuel.

Ferdinand Porsche was the brain behind the Auto Union racing cars. He designed them for the new motor-vehicle manufacturing group of that name that had been created in 1932 by a merger of the Audi, DKW, Horch and Wanderer brands, and supervised their construction and testing from March 1933 onwards at Auto Union’s racing department, which was located at the Horch factory in Zwickau. Approval of his design was subject to the engines developing at least 250bhp at 4500 rpm. Driver Hans Stuck confirmed this with a world speed record run on the Avus circuit in March 1934.

During the Avus race held shortly afterwards, the new Auto Union racing cars put up a most impressive show. Even during practice, Hans Stuck’s average lap speed of 152mph had made it clear who was the fastest contender. Although the race itself was marred by rain, Auto Union outpaced the other entrants (with Momberger recording the highest average speed of 137mph). By the tenth lap, Stuck had built up a whole minute’s lead over his nearest rivals – but then a fault developed. At the finishing line, Momberger was third, behind Alfa Romeo drivers Guy Moll and Achille Varzi, so that a place on the podium was secure. And incidentally, the competing team with the three-pointed star as its badge was still struggling with obstinate technical problems and chose not to enter for this race at all.

The Auto Union Grand Prix cars went through three stages of improvement by the 1937 season:

1934 Type A: 295bhp

1935 Type B: 375bhp

1936/37 Type C: 520bhp

During this period, the basic design concept remained unchanged. The V16 engine was in the centre of the chassis, behind the driver’s seat, and thus anticipated by several decades the layout used almost exclusively on modern racing cars. In its final form, the engine had a displacement of 6.0-litres and was extremely flexible: its maximum torque was 87 mkg at 2500 rpm, which meant that only a four-speed gearbox was necessary. A single camshaft operated all 32 valves; the crankshaft, originally a one-piece unit, was soon replaced by a version developed by Hirth, a specialist company. This consisted of individual segments bolted together through splined couplings.

The most famous drivers of these cars were Bernd Rosemeyer, Hans Stuck, Hermann Paul Müller, Ernst von Delius, Rudolf Hasse and Achille Varzi.

For the 1938 season, the formula changed and, since Ferdinand Porsche’s contract had terminated and he was no longer available, Chief Engineer Robert Eberan von Eberhorst drafted out a new design.

It was an expensive operation: from the first to the final racing season, expenditure rose from 1.3 to 2.5 Reichsmarks (RM). In 1935, a complete racing car cost about 50,000 RM; four years later, the figure had risen to about 70,000 RM. A staff of approximately 60, including the race mechanics, was needed in the racing department, which was formed in 1933. Its members were specially chosen, in most cases from the workforce of the Horch factory in Zwickau, where the racing department was located.

Between 1934 and 1939, Auto Union spent about 13.2 RM on Grand Prix racing, and received approximately 2.7 RM in subsidies from the government, an annual average of about 20 percent of its costs. In those years, Auto Union entered for 61 circuit races in all, 30 of them Grand Prix events. It won 24 of the races for which it entered and also took 23 second and 17 third places. In 1934, 1936 and 1938 an Auto Union driver was German road racing champion.

Auto Union learned a great deal from motor sport: aerodynamics, weight-saving construction and high-performance engines were all at the heart of its philosophy. At the same time, these specialised, highly tuned cars demonstrated the immense technical know-how, the precision machining methods and the skills possessed by Auto Union’s employees after many years of supplying products of consistent high quality.

Although the war put paid to the Silver Arrows' greatest sporting achievements, their legacy continues to live on.