Auto Union’s ultimate Grand Prix challenger was the two-stage supercharged V12 D-type. Mick Walsh braves the 485bhp Mercedes-Benz beater from Chemnitz.
There’s nothing like the routine of starting an Auto Union’s 3-litre, triple-cam V12. With bonnet removed from its brutal, slug-like form, three specialists from Crosthwaite & Gardiner perform the well-practised ritual of preparing this mid-engined 1939 titan. First all the plugs are removed from the magnificent Robert Eberan von Eberhorst-designed 60˚ V12 before the remote starter motor is plugged into the tail to crank up the oil pressure. Once the needles prick up on the black aviation instruments, the next stage is priming four-star into the twin Solex carburettors that feed the mighty two-stage superchargers. Space is tight at the back end above the de Dion axle and ZF differential, so it’s done with a brass syringe.
Once the floats are full, the final stage is ready. We’re running a light load of methanol in the rear tank behind the cockpit rather than the full race level in the side pannier tanks. The four-star is only squirted into the carbs for start-up whereupon the twin aircraft DB pumps behind the driver’s head start feeding the high-octane 50/40/10 mix of methanol, four-star and toluene bonding agent. After the peaceful, methodical routine, the fearsome high-torque V12 erupts like a deafening rifle barrage before the methanol is sucked into the heads. Then the ferocious cackle turns into a clear, blood-curdling roar. With throttle opened, the noise peaks with a painful, brutal blare. I swore not to wear earplugs under a linen helmet, determined to get the full effect of this mighty motor, but quickly understood the knowing smiles of the C&G crew.
While the oil warms, the steering-wheel lock is released and the broad, leather-covered four-spoke is removed for access. Nuvolari would clamber in with the wheel in place but bulkier, taller aces such as Hans Stuck and Hermann Müller needed more room. With narrow ribbed footwell between the beefy oval chassis tubes, and supportive but upright cord seat, the cockpit is wide but short. Considering the power on tap, the drilled, widely spaced pedals look almost dainty hinged off the bottom bar. It’s impossible to heel and toe. Compared to period rivals, the D-type is flush with gauges, dominated by the big rev counter that reads to 8000rpm plus five smaller dials and a three-step magneto switch. Surprisingly, there are two oil pressure gauges, for the crank and camshaft. “They’ll both dance around but if one is at odds with the other, something is amiss,” says engine builder Ian Harold.
The V12 could rev to 10,000rpm but drivers didn’t usually exceed 7000rpm, where power peaked at a potent 485bhp. Weighing in at 1875lb (850kg), that gave a stonking 579bhp per ton. More handy was the maximum torque of 404lb ft at 4000rpm. With roller mains for its fabulous Hirth built-up crankshaft, the V12’s character contrasted with the earlier V16, revving higher, quicker and smoother.
With wheel locked back, I’m instructed that second is ideal to start in because of the torque. Down to the right between the seat corner and petrol tank is a stubby, chunky lever sitting in a five-speed gate with a dog-leg first inside and forward. This works an unfeasibly long rod linkage to the ’box, way back behind the engine.
The clutch is surprisingly light, with good bite and feel, but at tentative speeds the gearbox feels slow and clumsy. Yet C&G’s Ian MacFarlane says this is the best Auto Union ’box: “With the C-type you have to snatch and crash the gears, but with the D-type’s dog clutches it’s cleaner and quicker.” At higher revs I discover that he’s right – the faster you go, the sharper the change.
The brakes too are phenomenal. Keen to test them before I start to explore the D-type’s dramatic punch, the wide, finely finned drums pull up straight and strong. Four shoes with a cylinder each, they are better adapted to drum distortion as heat builds up during a long battle. This complex, dual-circuit set-up was the best of its day and it really inspires confidence.
Out of fast turns the engine’s response is thunderous: in second or third the torque will easily spin the narrow 7x19in rears. Yet, with the weight over them, it predictably puts the power down better than any front-engined racer. Expecting a fierce late surge, the performance is strident and progressive as long as you are on the power. But feather the throttle and the engine chokes. Most dramatic is the backfire when you lift off into a tight turn. As with the brutal exhaust bark, you feel everything through your upper body.
Pushing harder through twistier, undulating turns, the chassis is impressively neutral compared to front-engined Alfas and Maseratis. With the 45:55 weight bias, which didn’t change during a long race even as fuel emptied, the D-type is remarkably sure-footed despite its narrow tyres. Von Eberhorst’s regret when watching GP cars in the ’60s was that he never had the wider tyres to fully exploit the Auto Union’s power.
The strangest sensation is the upright seat combined with the close, vertical wheel. Unlike later laydown positions, you don’t feel part of the car and it’s difficult to gauge what the rear end is doing. It’s little wonder test drivers spun Auto Unions several times before adjusting to their impressive but knife-edge limits. Unlike front-engined racers, you rarely see shots of D-types in lurid, opposite-lock slides because its neutral balance was better exploited by the smoother style and feel of ’bike riders. Hardest work is the steering. You expect the triple-thread cam-type box to lighten up but, with no stretch to the wheel, it’s a physical action that needs upper body strength as much as arm muscles. With two turns lock-to-lock, the action is high-geared and, despite the damping provided by a flexible clutch between the column and gear case, there’s still a fair amount of kickback. The alarming wheel flex maybe worked as an extra damper. More worrying is the tramp as you charge into a rough corner or over a crossing. On the paving at Belgrade, Nuvolari must have felt every stone through his muscular arms but quality hydraulic and friction dampers saved his back over a 2½-hour race.
After 15 laps I pull over feeling as if I’ve done a tough workout: I ache right through from my teeth to my torso from the noise, concentration and steering effort. As the engine clicks and hisses, I think about a haunting photo discovered by Walter Baumer of a D-type ditched in a deep gully under the trees at Spa on a black June day in ’39. It was the first motor race for young Georg ‘Schorsch’ Meier. Just imagine starting your car career at the awesome, rain-soaked Ardennes road circuit. Running an impressive sixth, Meier was overtaking a back-marker through Blanchimont when the slower Maserati moved across and forced him into a lurid spin. The moody shot says it all, with rear body crushed, steering wheel discarded nearby and tell-tale rev counter needle frozen at 6000rpm. On the long walk back to the pits, Meier witnessed Dick Seaman’s explosive, fatal impact. The following weekend Meier was back on a works BMW motorcycle, winning the Dutch GP at Assen. Looking at the plate-sized VDU rev counter, I couldn’t help thinking about Meier’s bravery and fortitude.
After the death of the brilliant Bernd Rosemeyer, AU team manager Dr Karl Feuereissen considered ’bike aces to be the most suitable candidates to control the tricky mid-engined cars. Nuvolari’s signing was the big scoop in ’38 but even the fearless, wiry Italian took several months to attune to the D-type. At least he had race car experience, unlike Meier and Ewald Kluge who were plucked from the ’bike-racing ranks for a test at the Nürburgring short circuit. For Meier, a talented rider who became the first foreigner to win the TT, it must have been like stepping from a Bücker Jungmeister biplane into an ME262 jet. “Before the test I had never driven any kind of racing car, just ordinary saloons in which I drove normally,” Meier recalled to Silver Arrows author Chris Nixon in ’86. “With nearly 500bhp, the difference from anything I’d driven was colossal. Of course I found it heavy to drive after motorcycles and the rear engine was always trying to slide round in front of me.” Meier practised for the Eifel GP: “Around the Nürburgring I found the Auto Union a handful on all those twists and turns and ups and downs. All that horsepower and those narrow tyres made it difficult, but I managed a lap of 10 mins 16 secs, just 9 secs slower than Nuvolari. At Spa, a circuit I knew well, I was more confident. The Auto Union handled beautifully on those fast corners. After setting good practice times, it was frustrating when the grid was decided by ballot.”
Meier was selected for the French GP at Reims on 7 July where he put the D-type on the third row position, just 5 secs behind Nuvolari. At the first fuel stop, Meier was running fourth: “In the pits my car caught fire. I jumped out but my arm was badly burned – I still have the scars. The mechanics quickly put out the fire and I went back into the race. My arm was very painful, so I held it out in the wind to cool it, although it made driving difficult as the Auto Union was very heavy to steer. But it was worth it, because I finished second behind team-mate Hermann [Müller]. It was a wonderful result for Auto Union.” Lewis Hamilton’s record is mighty but to come second in only your second car race is staggering. The following week Meier won his second motorcycle GP in a fortnight at Spa.
After Mercedes dominated at Bern, Nuvolari claimed the last race of this amazing era for Auto Union, the Yugoslavian GP around the bumpy Belgrade park circuit. Mysteriously, Lang was announced European Champion for Mercedes but Müller should have won it for Auto Union having out-scored his rival. With the onset of war, the German ruling body changed the scoring system and Müller never got the recognition he deserved. Even Nuvolari acknowledged the pace of the 30-year old from Bielefeld who’d also started on ’bikes. After the war he was back at the Chemnitz factory but as a prisoner working as a woodcutter. That’s all part of the magnetism of these amazing, underdog German challengers.
The C&G team has been converted too after its unique restoration experience. “Mercedes are over-engineered,” says project co-ordinator Clive Robbins, “and, with an unlimited budget, they were just showing off. They are too sophisticated. Auto Unions were built to a price but were no way compromised. It’s amazing what they did with lesser resources. The D-type was a major step forward and much easier to drive.”
That of course is all relative. Imagine holding this magnificent machine at 180mph down the old Nationale N31, exhaust stubbs blasting exotic fumes as the V12 yowls like a bull at stud. And with a badly burnt arm. Awesome.
This article was originally published in the September 2007 issue of Classic & Sports Car magazine, which retains the copyright to all words and images.