The SLR Phenomenon - Past and Future

The Stuttgart-based engineers conducted rigorous tests to make sure the engine would last. First, it was put through its paces at race speed over a distance of more than 6,000 miles, then subjected to a 32-hour non-stop run on a test rig.

This exhaustive test program was a key element in preparing for endurance road races such as the Mille Miglia, Tourist Trophy and Targa Florio, where reliability and durability was even more important than raw speed. The experience gained from pre-season testing paid dividends for the Mercedes team and helped earn the 300SLR a formidable reputation: the Silver Arrow engine, chassis and bodywork proved virtually indestructible.

"The car's powers of endurance are quite unbelievable," exclaimed Peter Collins in October 1955 after claiming victory in the Targa Florio. "This is a highly developed racing machine which also happens to be built like a tank, only with the lightning reactions of a wild cat. It is a truly magnificent feat of automotive construction."

An Engineer with Gasoline in his Blood

Uhlenhaut frequently displayed a talent for improvisation. For example, during the 1955 Buenos Aires race, Stirling Moss complained that excessive force was required to brake effectively in his W196. Uhlenhaut got down on his hands and knees underneath a service truck, plucked out its brake booster unit and promptly fitted it into the W196.

High-Strength Filigree under the Skin

However, the "three-dimensional tubular steel frame" required more room underneath the doors than earlier designs, which meant that the door sills had to be moved up, ruling out the use of conventional doors. As a result, the team simply mounted the hinges to the roof, allowing the doors to open upwards instead of to the side, and the legendary gullwing doors were born. Rudolf Uhlenhaut used this same design for the 300SLR frame, as it had proved to be not only rigid and stable, but also extremely light. The tubular steel frame weighed only 110 pounds. While the engine alone accounted for 514 pounds, the 1955 Mille Miglia version of the SLR tipped the scales at less than 2,000 pounds.

To keep the hood as low as possible, the straight-eight engine was mounted at a 33-degree angle. However, the driveshaft then ran from the clutch at an angle under the driver's seat to the transmission, which was located behind the rear axle. As a result, the driver had to straddle the driveshaft tunnel, operating the clutch pedal on the left, the accelerator and brakes on the right!

An Air Brake is Developed For the 300SLR

The idea for this "wind brake" came from director of motorsports Alfred Neubauer, who was looking to develop a system to reduce the wear on conventional brakes and tires during long-distance races such as Le Mans and Reims. Neubauer wanted to use wind resistance to slow the car in particular at Le Mans, as the French track forced drivers to use the brakes hard and often to bring the car down from its maximum speed to as little as 25 mph. Although Mercedes-Benz enjoyed considerable on-track success in 1955, its winning run was overshadowed mid-season by a tragic accident during the Le Mans 24-hour race. Forced off the track as it approached the pit lane, one of the 300SLR racing sports cars was unable to stop and careered into a spectator grandstand. In all, 82 people were killed in what was clearly an appalling disaster. Although they were leading, the Mercedes team called all of its cars into the pits and retired them from the race.

"Uhlenhaut Coupe" Becomes the Fastest Sports Car of its Time

Rudolf Uhlenhaut's new "company car," which he appeared in for the first time at the Swedish Formula 1 circuit, provided a fascinating side-show to the race itself. Spurred on by Mercedes' success in 1955, the Stuttgart engineer had spent time between races mulling over the idea of fitting the open 300SLR racing sports car with an enclosed cockpit for future endurance events.

Uhlenhaut's new coupe recorded a speed of 180 mph during a test conducted by "Automobil Revue" magazine at four o'clock in the morning on a closed section of motorway outside Munich. "We are driving a car which barely takes a second to overtake the rest of the traffic and for which 120 mph on a quiet motorway is little more than walking pace. With its unflappable handling through corners, it treats the laws of centrifugal force with apparent disdain," scribbled the lucky test reporter after a total of more than 2,000 miles. His only regret was that this was a sports car "which we will never be able to buy and which the average driver would never buy anyway." Only two examples of the SLR coupe were ever built.

For the SLR coupe's bodywork, the Mercedes engineers used ‘Elektron', an easy-to-work magnesium alloy which is even lighter than aluminum. The cabin resembled an aircraft cockpit, and the curved windshield generated little wind resistance. As in the 300SLR racing sports car, the engine in the "Uhlenhaut Coupe" was angled, and again, the driver had to control the pedals with his legs apart. The massive brake drums on the driven axles were moved inboard, to reduce unsprung weight and improve handling.

For anyone not already in the know, opening the boot lid was something of a mystery, with the inconspicuous "D" (for Germany) sign serving as the release lever.

Rudolf Uhlenhaut later called the SLR coupe "the fastest ‘company car' the company has ever built." The coupe attracted attention wherever it went, thanks to its standing not only as the fastest car registered for road use but also, one can assume, the loudest.

As a result, the police were only willing to grant it a license for road use if Uhlenhaut agreed to fit a muffler to the two exhaust pipes whenever he took the car out in public. Although the part in question - which was about the size of a suitcase - had the desired muffling effect, it jutted out noticeably from the right-hand side of the car and looked unwieldy. This could be the reason why old photos of the "Uhlenhaut Coupe" tend to show the left-hand side of the car. No matter, the excitement surrounding the car remained unaffected.

A Farewell to Motorsports

In 1959 Uhlenhaut took over as the head of passenger-car development at Mercedes-Benz and continued to define the technology and character of the brand's cars until his retirement in 1972. Rudolf Uhlenhaut died on May 8, 1989 just short of his 83rd birthday.

As the technical inspiration behind the Formula 1 Silver Arrows and the SLR racing sports car, as well as the creator of the 300SL Gullwing, Uhlenhaut left a legacy of very special cars. The "Uhlenhaut Coupe" of 1955 was without doubt one of the most outstanding super sports cars ever produced. For experts and motor racing enthusiasts alike, its name is synonymous with all-round technical genius, driving pleasure and reliability.

Portraits - The legendary SLR and some of its drivers

Sir Stirling Moss: A Life in the Fast Lane

The son of a dentist from London's West End, Moss grew up surrounded by horsepower in the most literal sense - his family was heavily involved in equestrian world. However, the 16-year-old Sterling invested the money he won in riding competitions not in a horse, but a race car. Although his father Alfred had himself been an amateur racing driver and finished 16th in the Indianapolis 500 in 1924, he decided to take away his son's car and gave him a bicycle instead.

In 1953, his ambition to be a racing driver undiminished, Moss contacted Alfred Neubauer. However, the Mercedes director of motorsports advised him to gather a bit more experience at grand-prix racing, and then they could talk again. This led Moss to sign with the Maserati racing team in 1954. At the Italian Grand Prix in Monza he seized his chance, leaving the rest of the field in his wake. It was only a ruptured oil line which deprived him of victory, with Juan Manuel Fangio capitalizing on his misfortune to take the win for Mercedes-Benz. However, Moss' performance earned him an invitation back to Untertürkheim. His contract as a Mercedes driver covered the period from January 1 to December 12, 1955, and Fangio now found himself in the company of another talented foreign driver on the Mercedes team.

The 1955 Mille Miglia is universally considered to be one of the greatest races of all time. At 7.22 a.m. on Sunday May 1, 1955, Stirling Moss and co-driver Denis Jenkinson roared away from the starting line in Brescia in their number-722 Mercedes-Benz 300SLR racing sports car. At 5.29 p.m., precisely ten hours, seven minutes and 48 seconds later, they crossed the finish line, having covered the 1,000-mile route at an average speed of nearly 100 miles per hour - a figure unmatched by anybody since.

Although Stirling Moss was never crowned Formula 1 World Champion, he came tantalizingly close on a number of occasions. Four years in a row between 1955 and 1958 he was the runner-up - three times behind Fangio. On the fourth occasion, in 1958, fellow countryman Mike Hawthorn bested Moss by just a single point.

Stirling Moss' record with Mercedes

Denis Jenkinson: The Writer with a Gift for Racing

He traveled to his first assignments as a reporter in an old Fiat 1500, his complete motorsporta library in the back seat. "He drove anything with wheels - and he drove them as fast as they would go," remembers a witness to Jenkinson's racing style. He started off with motorbikes and enjoyed considerable success on two wheels. Indeed, Jenks became world side-car champion in 1949 alongside Eric Oliver.

Jenkinson had always had a dream of taking part in the Mille Miglia, tasting the action and then writing about his experience. "But only as a co-driver to Stirling Moss. I'd only want to sit next to him, not anyone else," he was keen to emphasize.

In 1955 his turn came: Jenks was to be Stirling Moss' co-driver in the number-722 Mercedes-Benz 300SLR racing sports car. During practice for the Mille Miglia, Jenkinson had noted down every detail of the route - every hill top, corner and bridge - on a roll of paper, which he then kept in a waterproof case. The "toilet roll, " as he called his road book, became a 15-foot roll of paper. During the race, Jenks and Moss communicated with each other using hand signals.

Part credit for the 1955 Mille Miglia record win should also go to the small man with the distinctive beard. Jenks remained loyal to Moss and completed another two Mille Miglias as Moss' co-driver after that memorable first win. Following Daimler-Benz' withdrawal from motorsports in 1955, the successful pairing continued to compete in the 1000-mile classic, racing on two further occasions for Maserati, including the final edition of the high-speed race in 1957.

Jenks lived the life of a recluse in a simply-furnished house, which was actually more like a workshop. "Why forty?" Jenks was heard to grumble at Goodwood in 1995, during the celebration to mark the 40th anniversary of their Mille Miglia victory. "If we don't want to hold out until the centenary, we could at least wait until the 50th anniversary." Unfortunately, Denis Jenkinson died in November 1996, and none other than Stirling Moss wrote of his former co-driver: "The world of motorsports has lost a very special person."

John Cooper Fitch: Speed in his Genes

In 1948, the latter-day John Cooper Fitch opened an MG sports-car dealer in White Plains, New York. In 1950, he combined the chassis from a Fiat 1100 with a Ford engine to construct the Fitch Model B racing car. In 13 races in 1951, Fitch recorded ten class wins and six overall victories, enough to secure him the American Sports Car Championship organized by the Sports Car Club of America. Shortly afterwards, Fitch was recruited by millionaire Briggs Cunningham to race for his team. At the Le Mans 24-hour race in 1952, Alfred Neubauer signed up Fitch as a factory driver for the Carrera Panamericana in November 1952 after the American was impressive in testing with a 300SL. Unfortunately, Mercedes' new arrival was disqualified from the Panamericana after an unintentional breach of race regulations.

In the 1955 Mille Miglia, Fitch took fifth place overall and first place in the series-production sports cars category in a 300SLR. However, one of his finest moments came in winning the Tourist Trophy later that year as co-driver to Stirling Moss in the legendary Mercedes racing sports car. After Daimler-Benz withdrew from motor racing in October 1955, Fitch was hired as a designer by the American car maker Chevrolet.

John Cooper Fitch's record with Mercedes

1955
Mille Miglia…………………5th
Tourist Trophy……………1st (as co-driver for Stirling Moss)
Targa Florio………………4th

Hans Herrmann: the Swabian Arrow

However, his first outing - at the wheel of a Porsche 356 in the 1952 Hessen Winter Tour - ended after Herrmann took a succession of wrong turns. It was a different story, though, in his next race - the ADAC Tour of Germany in April 1952 - with the Stuttgart driver taking a class victory. The determined Herrmann was now beginning to get noticed, and Mercedes director of motorsports Alfred Neubauer invited him to a junior driver's competition in autumn 1953 at the Nürburgring. Herrmann made the most of his opportunity in the Mercedes 300SL, and duly qualified for the Mercedes works team.

Hans Herrmann's first Formula 1 race was the French Grand Prix in Reims in July 1954, where he was forced to retire with engine trouble. He was to endure more bad luck a year later, when he hit a crash barrier in his Formula 1 car during practice for the Monaco Grand Prix. Then, later that year in the legendary Mille Miglia, Herrmann had to retire again, this time with a defective fuel tank.

It wasn't until the princely age of 42 that Hans Herrmann finally retired from competitive racing, signing off on June 14, 1970 with one final victory in the Le Mans 24 hours, at the wheel of a Porsche.

Hans Herrmann's record with Mercedes

1955
Argentinean GP.....4th
Buenos Aires GP....Did not finish
Mille Miglia...........Did not finish