In modern motor racing, German manufacturer Audi is known for its sports racing roadsters like the R8 which won Le Mans five times, and the pioneering diesel-engined R10.
But in the 1930s, it built open-wheeled Grand Prix cars, called Auto Unions, with a ground-breaking rear-engined layout and fearsome horsepower.
Auto Union, whose GP cars became the first racing cars to bear Audi’s four ring emblem, was established in 1933.
In the following four years, it had taken part in 54 races, winning 32 and setting 15 world and 23 class records with the A, B, C and D-type single-seater racing cars.
The cars were difficult to drive, and six-litre V16 engined versions pumped out a staggering 545bhp.
In 1937, one was the first car to exceed 400km/h on a closed-off public road.
In 1938 to meet new regulations, Auto Union used a 3.0-litre V12 developing 500bhp in a car that weighed a total of 850kg.
Auto Union drivers included the legendary Bernd Rosemeyer, Tazio Nuvolari and Hans Stuck who drove these mammoth V12 and V16 heavyweights to glory at speeds of more than 240mph (385km/h).
The Auto Union was the first successful mid-engined Grand Prix car (positioned behind the driver and ahead of the rear axle), the precursor of current Formula 1 design. It would take 27 years from when Stuck set new world speed records on the Auto Union A-type’s 1934 debut for this layout to become the norm in Grand Prix racing.
British restoration experts, Roach Manufacturing plus Crosthwaite & Gardiner have built a 1939 Auto Union D-Type replica.
The D-Type’s first race with its unusual double-supercharger engine configuration was the 1939 Belgium Grand Prix, and H.P. Muller won the car’s very next race (French GP).
Audi’s museum in Ingolstadt, Germany, has a restored V12 mid-engined 1938 Auto Union D-Type.
Its chassis is one of the few to survive the exodus to the Soviet Union at the end of World War II in 1945.