In Caracciola's footsteps

An irresistible opportunity to take a pedigree Mercedes to the Goodwood hill’s summit

Late on Sunday afternoon at the Goodwood Festival of Speed, I was offered a drive in one of the Mercedes-Benz Museum’s 60-year-old W194 300SL coupés.

Of course, I rudely rejected any such proposal (this bit isn’t true). Having driven one of their two magnificent, muscle-bound (and utterly deafening) 300SLR Uhlenhaut coupés, the rather cramped cockpit of the lightweight 300SL came as the first surprise. Once on the move, the SL’s eager agility and sure-footed, nimble feel came as the second. Indeed, aiming this historic little aerodyne up the Goodwood hill was a revelation, emphasising how the W194 had been conceived as the then cash-strapped Daimler-Benz company’s riposte to Ferrari’s contemporary heavyweight 4½-litre V12 engined sports cars. The German engineers – restricted to a production-based power unit - built light to maximise manoeuvrability and power-to-weight ratio.

hey were impressed by the ine example of Jaguar’s C-type, which had won at Le Mans in 1951 using a lightweight frame and body with a production-based six-cylinder engine and gearbox plus many other standard parts.

Mercedes-Benz technical director Fritz Nallinger wanted to do something similar for Mercedes’ post-war return to racing in 1952, and in his company’s latest three-litre 300 saloon – the W186 – he had the perfect donor. Frame and bodywork apart, virtually all the 300 saloon’s basic design elements would be adopted for the 300SL – Sport Leicht (Lightweight) – racing coupés. But since the production-based iron-block engine and drive-line assemblies were heavy for racing, designer Franz Roller’s engineering team saved every ounce possible in the new coupé’s chassis and body.

Perhaps most significantly, senior pre-war racing engineer Rudi Uhlenhaut had worked for two years with the British Army’s Royal Electrical & Mechanical Engineers in occupied Germany. While with them he read about the 500cc ‘poor man’s motor racing’ movement in Great Britain, and about Italy’s Dante Giacosa-designed space-frame Cisitalia D46 lightweight monoposti.

He had then designed a rear-engined racing car of his own, with a very deep multi-tubular chassis frame that peaked at the scuttle centre. The lattice spaceframe chassis for the 300SL would emerge with a similar high point, while every component tube was either in tension or compression, as a true spaceframe should be.

As Uhlenhaut once explained to me, if every tube intersection had been universally jointed, or just tied together with loppy cloth, the frame would still retain its shape, regardless.

In his fantastic history of Mercedes-Benz’s racing cars, Karl Ludvigsen cites the 1952 W194 chassis frame as having been as stiff in torsion as the oval-tube structure of the pre-war W154 Grand Prix chassis, yet it weighed only 110lbs against the W154’s 155lbs. And the post-war space-frame didn’t require any of the extra body supports that added further mass to the pre-war chassis.

To achieve the W194 frame’s exceptional rigidity, its cockpit-bay structure had to be deep, dictating high sills where doors would normally be cut. And this deep-sill requirement is what prompted the distinctive gullwing door design. To lower the bonnet line, the 300-derived engine was canted 50 degrees from vertical with the crankshaft centre offset to the car’s right, providing a wider footwell for the driver (but tough luck on the passenger).

The iron-cased four-speed gearbox from the production 300 was used, with long-throw, centerline gearchange. Alin drum brakes (as special as the chassis) and Sindelingen-made aluminium body completed the recipe. The W194’s design team missed their dry-weight target of 780kg – about 1716lb – but 1914lb was judged to be good enough. Breathing through three Solex carburettors, their modified 300-based engine developed slightly more than 170bhp at 5200rpm, while rival Jaguars, Ferraris, Cunninghams and Talbots were blessed with at least 200bhp.

The works team of these 300SL coupés made its debut in the 1952 Mille Miglia – the new cars’ ine shape and straight-line speed putting the wind up young Stirling Moss, who warned Jaguar that the C-type’s shape was hopeless in comparison – which led directly to that year’s ‘droop snoot’ C-type flop at Le Mans. Karl Kling led to Rome before knock-off hub delays helped Giovanni Bracco win for Ferrari, with the German second, team-mate Rudi Caracciola fourth and Herrmann Lang retiring after hitting a stone that unshipped his car’s back axle.

Two weeks later, four SLs were ielded in the Swiss GP supporting race at Bern’s Bremgarten circuit. But while Kling, Lang and Fritz Riess inished triumphantly 1-2-3, Caracciola had his maroon car’s rear brakes lock and he smashed head-on into a trackside tree, sustaining leg injuries that ended the veteran champion’s racing career.

Three new SLs contested Le Mans, and finished 1-2 after the collapse of the Jaguar and Talbot challenges – the latter when single-handed ‘Levegh’s car threw a con-rod while leading into the 24th hour. Lang/Riess shared the winning car, with Theo Helfrich/ Hans Niedermayer second.

Four works 300SLs then ran at the Nürburgring German GP meeting on August 2, as ‘chop-top’ open spyders. Kling’s was a new, even shorter-wheelbase car that had initially sported a supercharged 230bhp engine. Astonishingly no team driver – nor engineer Uhlenhaut – could get this car around the 14-mile Nürburgring any more than a mere 0.3sec faster than its unsupercharged sisters, despite having 50 more horsepower. All four SLs thus raced unblown and Lang headed a 1-2-3-4 finish.

The Daimler-Benz importer in Mexico City pleaded for Stuttgart to enter the season-end Carrera PanAmericana. Two 300SL coupés and two spyders were shipped. After Karl Kling/Hans Klenk (below) were joined by a buzzard bursting through their windscreen – and Hermann Lang/Erwin Grupp struck a dog – they inished 1-2 in this order, humbling Ferrari. Kling averaged 102mph – a staggering feat over 1933 miles of public highway, 60 long years ago.

The ‘Prat Motors’ liveried car that I drove – shut up – is the second-placed Lang/Grupp Carrera car, and lifting the carpet on the cabin deck behind its seats revealed original alloy panels bearing a peeling coat of burgundy paint. When the Rennabteilung had required a fresh coupé for the Mexican trip they grafted a new front frame onto Caracciola’s crashed Bremgarten car, and that’s the coupé I drove. To say I felt privileged is an understatement. A Caracciola and Lang car, no less. That will do nicely, thanks.

Doug Nye