Pre-war Auto Union Grand Prix cars are, probably, one of the most famous racing cars in history. Indeed, German silver cars were technically most advanced racing machines of its time, as well as one of the most successful ones. The rivalry between Auto Union and Mercedes in the 1930s is definitely one of the pinnacles of motorsport history. Type A Auto Unions were built in 1934 and were powered by V16 4.L engine capable of 295 PS. The chassis was constructed with steel tube leader framework. As a consequence of the mid engine design the driver was placed far forward. The main fuel tank was mounted between the driver seat and the engine. Uneven weight distribution and the large amount of weight in the rear of the car made Auto Unions difficult to handle. Along with the main design with the open wheels and open cockpit, several streamlined cars (speedlimousines) with full cabin and enclosed rear wheels were built and used in some races and record runs. Type B built in 1935 was the second car in series of Auto Union racers produced in 1934 – 1939. The car was based in 1934 A-type model, but with very significant modifications. The original Porsche-designed V16 engine now had bigger valves and new cylinders, increasing compression from 7 to 8.95. The displacement of the engine was increased to 4,954 cubic centimeters (instead of 4,358 cc in A-type), as well as compressor pressure (0.75 bars vs 0.61),which resulted in the increase of power to 375 PS compared to 295 PS in type A. Chassis was constructed using new longer 105 mm chassis tubes. The cooling system was totally rebuilt with the frame no longer carrying water to the radiator. The two tanks were replaced with a single 210 liter main tank behind the driver keep fuel for 320 km Grand Prix distance. German drivers Hans Stuck, Bernd Rosemeyer and Italian Achille Varzi were regular Auto Union drivers for Grand Epreuves and major Hill Climbs, while Hermann zu Leiningen and Paul Pietsch occasionally drove in some other races. Despite at least 4 new B-type were built, three out of 5 1934 A cars were upgraded for 1935 season with higher compression, improved gearbox and brakes. Two of them were streamlined speedlimousines which were raced in 1935 Avus-Rennen in Berlin. The races held at Avus circuit which actually was two long stretches of public Autobahn connected by two short curves. The configuration of the circuit predispose to very high speed, so streamlined version might have some advantage over regular open-cockpit cars. Four Auto Unions were entered for the Avus race: Stuck and Varzi used conventional GP cars, and A-type modified streamliners were given to Rosemeyer and zu Leiningen. Talented 25-years old Rosemeyer was newcomer to the team while for 33-years old Nobleman Prince zu Leiningen it was his 6 season in Grand Prix racing. But for both of them the race ended equally unsuccessfully with the retirements in preliminary heats. Rosemeyer’s car suffered from tire puncture and engine problems in heat 1, and zu Leiningen did not finish heat 2 due to engine failure. This Brumm model of the car driven by zu Leiningen is designated as Auto Union B, but actually it is type A chassis modified for 1935 season.
|Herman zu Leiningen||3||Auto Union AG|