Auto Union Rennstall

Auto Union AG was formed in 1932 from the merger of four German automobile manufacturers: Audi, DKW, Horch, and Wanderer. Auto Union chairman Klaus von Oertzen sought a showpiece racing project to establish the new company's identity. At the 1933 Berlin Motor Show, German Chancellor Adolf Hitler announced state funding for a high-speed German automotive racing programme, allocating an annual sum of 500,000 Reichsmarks to support competitive Grand Prix development. Rather than funding one team, Hitler agreed that both Auto Union and Mercedes-Benz should receive equal state support, with each team receiving 250,000 Reichsmarks annually — a figure that later grew considerably.

Auto Union engaged Dr. Ferdinand Porsche, who had already developed his own P-Wagen project racing car around the new 750 kg formula, and purchased Porsche's Hochleistungsfahrzeugbau company for 75,000 Reichsmarks, relocating its operations to the Horch plant in Zwickau. The resulting car was a radical design unlike any contemporary Grand Prix machine.

The Auto Union racing cars, types A through D, were built as Grand Prix racing cars from 1934 to 1939. Their most distinctive feature was a rear mid-engine, rear-wheel-drive layout — an arrangement largely without precedent in top-level Grand Prix racing at the time and not revisited in Formula One until the late 1950s. The fuel tank was located in the centre of the car, directly behind the driver and ahead of the engine, ensuring that the car's front-rear weight distribution remained consistent as fuel was consumed. The cars were supercharged and eventually produced almost 550 horsepower, with the engine generating sufficient torque that driver Bernd Rosemeyer once drove an Auto Union around the Nürburgring in a single gear to demonstrate the powertrain's flexibility.

The cars' handling was widely considered difficult, owing to the rear weight bias and extreme power. Despite this, their acceleration and outright pace were formidable.

The initial 1934 season was led by Hans Stuck, who won the German, Swiss, and Czechoslovak Grands Prix and claimed the European Mountain Championship in hillclimb events. In 1935, Achille Varzi joined the team and won the Tunis Grand Prix and Coppa Acerbo, while Stuck again took the European Mountain Championship and a new sensation, Bernd Rosemeyer, won the Czech Grand Prix.

1936 was Auto Union's most successful season. The Type C, powered by a 6-litre engine producing 520 bhp, was dominant in Rosemeyer's hands. He won the Eifelrennen, German, Swiss, and Italian Grands Prix as well as the Coppa Acerbo, claiming the European Championship — the team's only drivers' title. In 1937, against the new and highly effective Mercedes-Benz W125, Auto Union won five races to Mercedes' seven. Rosemeyer took the Eifel and Donington Grands Prix, the Coppa Acerbo, and the Vanderbilt Cup.

Rosemeyer was killed in January 1938 during an attempt on the land speed record on a German autobahn, a major blow to the team. Tazio Nuvolari was recruited and won the Italian and Donington Grands Prix that year. In 1939, Nuvolari won the Yugoslavia Grand Prix and Hermann P. Müller won the French Grand Prix before war brought racing to a halt.

In total, between 1935 and 1937, Auto Union drivers won 25 races.

The Second World War ended Auto Union's racing programme. The company's Saxon plants were occupied by the Red Army following the Allied victory, and the racing cars stored in a colliery were removed to Moscow. Auto Union AG was subsequently liquidated in the Soviet-occupied zone. The company was re-founded in Ingolstadt, Bavaria, in 1949, eventually evolving through successive mergers and Volkswagen's acquisition into the modern Audi company. The four-ring logo, symbolising the original four constituent marques, survives as the trademark of Audi AG to this day.

Auto Union Rennstall remains one of the most technically audacious racing programmes in the history of motorsport. The team's mid-engined, rear-mounted power configuration anticipated the layout that would become universal in single-seater racing two decades later. Drivers Bernd Rosemeyer, Tazio Nuvolari, and Hans Stuck are among the most revered figures of the pre-war Grand Prix era, and the Silver Arrow campaigns of Auto Union and Mercedes-Benz together defined a period of unparalleled German dominance in international motor racing.