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AUTO UNION TYPE C

THERE WAS A TIME when Grand Prix cars had front engines. Ah, but the exception was exceptional indeed: the Auto Union. What’s more, these cars were documented by two giants of automotive journalism, Laurence Pomeroy and Karl Ludvigsen. Here are tidbits about the 1936–1937 Auto Union Type C gleaned from Pomeroy’s The Grand Prix Car, Volumes 1 and 2, 1955, and Ludvigsen’s “Auto Union Grand Prix Car,” in Automobile Quarterly; Volume VIII, Number 1, Summer 1969.

Type C Auto Unions by Gotschke. The Automobile Quarterly issue enhanced Ludvigsen’s technical analyses with “Auto Union Rennwagen: Paintings by Walter Gotschke.”

“May 10, 1936. The C-Type in a driving sandstorm during the Tripoli GP at Mellaha. In addition to battling the Alfas and Mercedes, Auto Union fought among themselves during this one. It was Achille Varzi and Hans Stuck who had the disagreement—and Varzi won out….” This and the following Gotschke illustrations are from Automobile Quarterly, Summer 1969.

Grand Prix Regulations at the Time. In 1934, the Association Internationale des Automobile Clubs Reconnus established what was essentially a Formula Libre, its principal regulation being a maximum weight of 750 kg (1653 lb). As a point of comparison, Formula One technical regulations for 2020 run for 111 densely packed pages and include a 745-kg minimum weight at all times during the event.

The 750-kg regulation ran through the end of 1937. And the mid-engine 6.0-liter, 16-cylinder, 520-hp Auto Union of 1936 was an example of this limit exploited to an extreme.

Troubled Grands Prix. By 1936, Grands Prix were getting caught up in international politics. The year before, Italy had invaded Abyssinia and the League of Nations imposed economic sanctions. Mussolini retaliated by boycotting French and British motorsports events. On March 7, 1936, Germany’s Third Reich, which supported both Auto Union and Mercedes-Benz Grand Prix teams, entered the demilitarized Rhineland. And on July 18, the Spanish Civil War erupted, with Germany testing its military hardware there as well.

The 1936 and 1937 Grands Prix. Though Alfa Romeo dominated non-championship Grands Prix, Auto Union and Mercedes-Benz overwhelmed the Italian Alfas and Maseratis and French Bugattis in the nine races of the 1936 and 1937 championships. Brend Rosemeyer’s Auto Union took first in three of the four 1936 events; Rudolf Hasse’s Auto Union was victorious once in 1937, with Mercedes taking the other four.

This and the following image by L.C. Cresswell in The Grand Prix Car.

The Auto Union C Type’s V-16. The Auto Union C Type was designed by Dr. Ing. h.c. Ferdinand Porsche. Originally 4.5 liters, its supercharged V-16 grew to 6.0 liters; power rose from 295 hp at 4500 rpm to 520 hp at 5000.

Cross section of the Auto Union 16-cylinder engine. Notice the lateral pushrods activating the exhaust valves from a single centrally located camshaft.

Pomeroy noted, “Dr. Porsche’s original concept centered around the use of the largest engine possible within the very rigourous weight limit of 750 kg, and on the first design a boost of only 10 lb. per sq. in. (1.66 ata) was used. Despite successive increases in engine size it was also necessary to raise the b.m.e.p. and boost pressures, and in 1937 the limit of a single Roots-type was reached.”

Pomeroy write that boost never grew beyond 13 psi gauge. To put this in perspective, today’s Formula One cars operate at around 3.5 bar (1 bar being atmosphere’s 14.5 psi, this is around 50 psi absolute, or 35.5 psi gauge).

A Potent Blend. Grand Prix cars of the Thirties were fueled by bizarre mixtures. Pomeroy called them “Petrol-Alcohol.” Ludvigsen got more specific: One fuel cited for the Auto Union V-16 cars was a blend of 60.0-percent alcohol, 20.0-percent benzol, 8.0-percent gasoline, 10.0-percent diethyl ether, 1.5-percent toluol/nitrobenzol, and 0.5-percent ricinus oil.

“October 22, 1938: Although the political situation threatened its cancellation, the Donington Grand Prix was finally held four weeks late, and British spectators were treated to a virtuoso performance by Tazio Nuvolari in the D-Type Auto Union.”

By the end of the era, both Auto Union and Mercedes-Benz were using such mixtures. “On twisty tracks,” Ludvigsen wrote, “the [3-liter] 1939 D-Type delivered about 2.3 miles per gallon of fuel. Not so highly boosted, the 1937 C-Type ran some twenty percent farther per gallon [delivering about 2.8 mpg] at approximately the same racing averages, in spite of having twice the displacement.”

A modern Formula One car, with its turbocharged hybrid powerplant, is said to get around 6.9 mpg. ds

© Dennis Simanaitis, SimanaitisSays.com, 2019

2 comments on “AUTO UNION TYPE C

  1. carmacarcounselor
    December 16, 2019

    I would be interested to learn how those horsepower numbers relate to modern SAE Net. I recall an article in an early Road & Track (late ’50s?) in which they quoted some figures on how much horsepower it took just to drive the supercharger.

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