Mercedes 300 SLR Coupe, Classic choice

PLEASE IMAGINE IT IS THE YEAR 1955, THAT YOU ARE A hardworking German accountant, and that you are poorling along the autobahn in your puny Messerschmitt Kabinenroller. Suddenly you hear thunder and instinctively look up. At this very instant a projectile on wheels swishes past your featherweight vehicle and your day is ruined. Was that a secret weapon, being tested by the armies of occupation? No, that was just the chief engineer at Mercedes-Benz driving his company car on his way to the work office.

The famous Mercedes-Benz engineer Rudolf Uhlenhaut, who led the way for a number of inventions and firsts used to drive an unlikely company car in this SLR Coupe. Mercedes 300 SLR Coupe, Classic choice

To start the story, we need to go back to the year 1906, and to London. It was there that Rudolf Uhlenhaut, the son of a German banker, was born. Brought up in a multilingual environment, he quickly decided that all he wanted to do was to be an engineer. In 1931 he joined the research and development department at Mercedes, and in 1936 became the head engineer of the sports department. When World War Two was over, he rejoined Mercedes as soon as it was possible and was put in charge of passenger car development

In mid-1951 he was put in charge of the programme to build a new road racing car, one that would be capable of blowing all competition, including Ferrari, out of the water. Rudolf decided to apply a lot of lateral thinking and designed a tubular spaceframe chassis with an incredibly low weight, to which all suspension members and the powertrain would be attached. To maintain torsional stiffness, Uhlenhaut's chassis had very prominent side sills, which all but precluded the installation of normal doors. Rudolf immediately decided to attach door hinges to the top of the cabin roof and thus the legendary Gullwing body was born.

DESIGN EXCELLENCE 

Rudi's relentless pursuit of excellence led him to design in 1955 an SLR-based coupe which could be utilised in long distance road races. Two examples of this exceptional car were quickly built, and both survive in the vaults of the Mercedes museum. One of them runs, but few people are permitted to drive it.

Back to 1955. The car was state of the art. The handsome body was fashioned out of the magnesium alloy Elektron, normally used for aircraft parts, such as propeller blades, as it is lighter than aluminum. The chassis was the same as the one used on the 300SLR (Stirling Moss's Mille Miglia car) and very similar to the one used in the Formula One car of the time. The engine was also carryover from the open top 300 SLR: eight cylinders, in line formation, canted to one side with a three-litre capacity. The desmodromic valvetrain the valves have no springs at all, something also found on some Ducati bike engines,) and direct mechanical fuel injection would make headlines now, let alone in 1955. The engine produced over 300bhp and was said to be exceptionally flexible, pulling without protest all the way from 1,000rpm to the 7,500rpm redline.

The power was taken from the crankshaft and conveyed to the rear wheels via a five-speed manual gearbox and a limitedslip differential. The engine's odd angle and the power take off meant that the floor tunnel housing the drive shaft was located between the driver's legs. It is a bit weird, to sit like Moss in his racer, with legs splayed, the clutch pedal on the left, and the brake and gas pedals on the right. Sir Stirling once told me that getting used to it was no problem at all. This car, known internally as the Uhlenhaut Coupe could really move, and to prove that, the German magazine Automobil Revue clocked it on an empty autobahn at 4am, at the average of 177mph, with a peak top speed of precisely 181mph. It was the perfect tool for a talented driver.

TESTING ONE 

And Uhlenhaut was one. When testing the Formula 1 car's suspension at the Hockenheimring in 1954, Uhlenhaut, of course driving the beast himself, came within 3.5 seconds of Fangio's best time at that circuit. He never raced, preferring instead a life on the side lines, helping his heroes beat everyone. Rudi was simply a genius as an engineer: who else would have come up with the idea for a hydraulically activated air brake or for the system which sprayed oil on brake drums to prevent wheel lockup?

But there are people at Mercedes who still remember the story the wild streak in Rudolf Uhlenhaut. The man lived outside Munich, and usually commuted to the Stuttgart factory at Unterturkheim every day by car. And this car, the unique SLR Coupe, was his company car. Imagine the empty autobhans in those days with no speed limits anywhere. The commute was around 125 miles and reputedly, Uhlenhaut was able to cover that in 52 minutes. To put that into perspective, the Stuttgart to Munich autobahn is not straight, like a road in Montana might be, and it has a number of tightening curves too. But that's not all.

That coolest of Mercedes engineers in history drove his car the way that the top drivers of the time drove theirs: braking as little as possible, drifting the car around corners. In order to be able to complete the last four-wheel drift of his commute in his driveway, Rudi installed the first power-operated gate in that part of Germany. Witnesses no longer remember if the gate was radio controlled or perhaps activated by a member of the Uhlenhaut household upon hearing the ground shaking bellow of that thoroughbred racing engine. Children from neighbouring houses were able to hide behind a fence in time when they heard Uhlenhaut approach: the deafening noise was a safety measure. Driving the coupe was more than a bit like driving a modern Formula 1 or DTM on the public road today, just think about that.

TRUE WONDER And one more thing. Do you know why so many great passenger cars were built by Mercedes between 1959 and 1972? Because a great guy named Uhlenhaut was in charge of passenger car development in those days. No wonder then...

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