Auto Union Type D (Single-Supercharged)

The scent of high-octane fuel at the start of the 1938 Grand Prix season was heavily laced with mourning. In January, the Auto Union squad had been brutally shattered by the death of their talisman, Bernd Rosemeyer, during a terrifying high-speed record attempt on the autobahn. Compounding this emotional devastation was a drastic alteration to the international rulebook. The governing AIACR had abolished the unrestricted 750 kg formula, mandating a maximum engine capacity of just 3.0-litre (183 cu in) for supercharged cars. To replace the monstrous, widow-making 6.0-litre (366 cu in) V16 Type C, Auto Union engineer Robert Eberan von Eberhorst stepped out of Ferdinand Porsche’s shadow to create the 1938 Auto Union Type D. It was a machine forced to battle not only the searing grief of its own racing department but also the ruthlessly efficient, state-sponsored might of the new Mercedes-Benz W154.

Beneath the meticulously louvred, unpainted aluminium skin of the Type D lay an exercise in mechanical refinement that finally tamed the mid-engined beast. Eberhorst discarded the heavy V16 in favour of a bespoke 60-degree V12. Displacing exactly 3.0-litre (183 cu in) and force-fed by a single Roots-type supercharger, this metallurgical jewel produced a staggering 420 bhp. Unlike the guttural, low-revving thunder of its predecessor, the new V12 emitted a frantic, high-pitched mechanical shriek as it tore towards its redline. Power was delivered to the rear cross-ply tyres through a robust five-speed manual transaxle. Crucially, the lethal handling characteristics of the older cars were eradicated. Eberhorst retained the mid-engine layout but pushed the driver’s seat slightly further back to improve the polar moment of inertia. More importantly, he banished the treacherous rear swing axles to the scrapheap, replacing them with a sophisticated De Dion rear suspension setup located by a Panhard rod. This transformed the chassis dynamics; the vicious snap-oversteer was replaced by a progressive, predictable balance. Stopping the 850 kg (1874 lbs) silver dart relied on massive, hydraulically operated aluminium finned drum brakes, which fought heroically against speeds exceeding 300 km/h (186 mph).

Despite the engineering brilliance of the Type D, the 1938 season commenced as a bleak, desperate struggle. The car was fast, but without Rosemeyer, Auto Union lacked a pilot capable of wrestling a mid-engined grand prix car to victory against the dominant Mercedes-Benz drivers. Salvation arrived in the diminutive, fearless form of Tazio Nuvolari. The legendary Italian ace, frustrated by the uncompetitive Alfa Romeos, signed with the German squad mid-season. Nuvolari, completely unfazed by the Auto Union’s unorthodox layout, quickly bent the single-supercharged Type D to his will. The combination was electrifying. In September, Nuvolari unleashed the full fury of the V12 on home soil, securing a deeply emotional, hard-fought victory at the Italian Grand Prix at Monza. A month later, the “Flying Mantuan” transported the Auto Union to the undulating parkland of the Donington Grand Prix. There, beneath the autumn leaves, Nuvolari put on a masterclass of car control, initiating glorious four-wheel drifts and utterly humiliating the Mercedes-Benz armada to claim a dominant win.

The Auto Union Type D Monoposto was a magnificent, shrieking vindication of the mid-engine philosophy. It proved unequivocally that when paired with a refined De Dion rear suspension, placing the engine behind the driver was not a lethal quirk, but the definitive architecture of racing speed. For the following 1939 season, the Type D would be upgraded with a complex twin-supercharger system to combat the relentless march of Mercedes-Benz engineering, yet it is the 1938 single-supercharged iteration that remains the purest expression of Eberhorst’s design. It stands as a glorious, screaming monument to resilience—the silver projectile that allowed a grieving team and an ageing Italian genius to conquer the Grand Prix world.