Professor Ferdinand Porsche was the genius behind the mid-engined Auto Union.The 750kg Formula for grand prix cars was originally scheduled to run from 1934 to 1936 inclusive, and put no limit on engine capacity, so the Professor designed his remarkable, Roots-supercharged V16 as a 6-litre unit, but decided to restrict it to 4.4 litres initially.The 1934 A-type Auto Union had a bore and stroke of 68x75mm (4358cc) and produced 295bhp at 4500rpm.
For the 1935 B-type, the bore was increased to 72.5 mm,giving 4951cc and the power rose to 375bhp at 4800rpm. Finally, for the 1936 C-type, the bore and stroke increased to 75x85mm, giving Porsche’s ultimate capacity of 6005cc, producing 520bhp at 5000rpm.
In this form the Auto Unions, led by the phenomenal Bernd Rosemeyer, swept all before them,giving MercedesBenz such a beating that the Stuttgart concern withdrew from racing before the Italian GR That year Rosemeyer secured the European Drivers’ Championship, the Mountain Championship and the German Road Championship.
The 750kg Formula was held over for 1937 and Professor Porsche saw no reason to alter his winning car. When the Avusrennen was scheduled for the end of May, Auto Union decided to build two fully-enclosed streamliners on C-type chassis for this high-speed event. These whetted Rosemeyer’s appetite for some speed records, which had up to that point been Hans Stuck’s domain.
Sadly, both cars apparently disappeared ‘somewhere in Russia’ after the war. No drawings or photographs of their construction survived, but we do know that they were tested in the wind tunnel of the Deutsche Versuchsanstalt für Luftfahrt in Berlin and produced the sensationally low drag coefficient of 0.237.
Driven at Avus by Rosemeyer and Luigi Fagioli, these were mechanically identical to the normal C-types raced by Ernst von Delius and Rudolf Hasse.
Although Rosemeyer failed to win at Avus, he had reached around 235mph on the straights. Just three days after winning the Eifel GP at the Nurburgring on June 13, he set six new records on the autobahn in one of the streamliners, including a Flying Mile at 242.09mph.The Land Speed Record then stood to Sir Malcolm Campbell and Bluebird at 301.1 mph, but that was on the wide open spaces of Utah Salt Flats. Bernd had been running on a two-lane autobahn.
In October 1937, during the official Rekordwoche on the same Frankfurt-Darmstadt autobahn, Rosemeyer became the first man to break the 250mph barrier on the road, improving his Flying Mile record to 252.46mph. He also set 15 other records with the two streamliners.