15 Nov 04
After World War II, Daimler-Benz launched a motorsport programme intended to revive memories of the successful Silver Arrow racers of the Thirties. Chief engineer Rudolf Uhlenhaut - said to have been a very talented driver who had beaten Fangio's lap times in testing - oversaw the construction of a lightweight tubular steel spaceframe chassis, consisting of grid-style tubing welded into a series of triangles, two large bulkheads each side for optimum torsional rigidity and independent coil-spring suspension. The bodywork teams at Mercedes' facilities at Unterturkheim and Sindelfingen produced a lightweight aluminium shell which demonstrated all the latest developments in aerodynamic theory, with integrated headlights and a low-riding stance; the finished prototypes had a drag coefficient of 0.25Cd, ground-breaking for the time. The light weight of the bodyshell compensated for the relatively heavy steel axles, developed from those of the 300-series production models of the time. Conventional doors could not be fitted, given the shape of the spaceframe construction, so a slightly awkward compromise was reached whereby a section of the coupe's roof and framed window pivoted upwards and outwards for the driver and co-driver to scramble in and out.
The engine - a development of Daimler-Benz's 2996cc straight-six also used in the 300 limousine and 300S coupe and cabriolet - was mounted at 50 degrees, giving a low centre of gravity and good weight distribution, as well as allowing for the long, low bonnet. This initial competition car's engine, the M-194 unit, featured three Solex carburettors, overhead valves suspended in a V-shape from the cylinder head and an overhead camshaft; it was good for 175bhp and worked with an all-synchromesh four-speed gearbox. Interior comforts were sparse: this was a stripped-out racing car, not a boulevard cruiser.
Making its debut in 1952, the 300SL - 300 to denote the 3.0-litre engine, SL "Sport Leicht", or "Sport Lightweight" - made an instant impact. Finishing in second and fourth places in the Mille Miglia thousand-mile road race of May '52, a three-car team then made a clean sweep in the Bern Grand Prix before going on to take first and second places in the Le Mans 24 Hours, setting a new average speed record of 155.575kmph. Shortly afterwards, four SLs took the first four places in a race at the Nurburgring - the fourth car to finish being the first roadster prototype. Towards the end of the year, four 300SLs with their engines boosted to 3.1-litres and 180bhp contested the gruelling and notoriously dangerous five-day Carrera Panamericana race through Mexico, taking first and second places despite a series of accidents, punctures and the controversial disqualification of one car for alleged technical infringements. After such a successful year, Mercedes switched to focusing on its eight-cylinder W196 single-seaters for Grand Prix events, and the SL story could have ended there if it hadn't been for the company's US importer, Max Hoffman.
