Jaguar XKSS
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Car producer : |
Jaguar |
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Model: |
XKSS |
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Year: |
1954-1957 |
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Type: |
Roadster |
The Jaguar D-Type is a sports racing car that was produced by Jaguar Cars Ltd. between 1954 and 1957. Although it shares many of its mechanical components with the C-Type, including the basic Straight-6 XK engine design (initially 3.4 litres and uprated to 3.8 litres in the late fifties), the structure of the car was radically different. The innovative monocoque construction brought aviation industry technology to competition car design, together with an aeronautical understanding of aerodynamic efficiency.
D-Types won the Le Mans 24-hour race in 1955, 1956 and 1957. After Jaguar temporarily retired from racing as a factory team, the company offered the remaining unfinished D-Types as XKSS versions whose extra road-going equipment made them eligible for production sports car races in America. In 1957 25 of these cars were in various stages of completion when a factory fire destroyed nine of them.
Total D-Type production is thought to have included 18 factory team cars, 53 customer cars, and 16 XKSS versions.
The structural design, revolutionary at the time, applied aeronautical technology. The "tub", or cockpit section, was of monocoque construction, mostly comprising sheets of aluminium alloy. Its elliptical shape and comparatively small cross-section provided torsional rigidity and reduced drag. To the front bulkhead was attached an aluminium tubing subframe for the engine, steering assembly, and front suspension. Rear suspension and final drive were mounted to the rear bulkhead. Fuel was carried in the tail and the designers followed aviation practice by specifying a deformable Marston Aviation Division bag in place of a conventional tank.
The aerodynamic bodywork was largely the work of Malcolm Sayer, who had joined Jaguar following a stint with the Bristol Aeroplane Company during the Second World War and later worked on the C-Type. For the D-Type, he insisted on a minimal frontal area. To reduce the XK engine's height, Jaguar's Chief Engineer William Haynes and former Bentley engineer Walter Hassan developed dry sump lubrication, and it has been said that the car's frontal area was also a consideration in canting the engine at 8½° from the vertical (which necessitated the offset bonnet bulge). Philip Porter, in his book Jaguar Sports Racing Cars, says that "more likely reason was to provide extra space for the ram pipes feeding the three twin-choke Weber carburettors." Reducing underbody drag contributed to the car's high top speed; for the long Mulsanne Straight at Le Mans, a fin was mounted behind the driver for aerodynamic stability. For the 1955 season, factory cars were fitted with a longer nose, which lengthened the car by 7½ inches and further increased maximum speed; and the headrest fairing and aerodynamic fin were combined as a single unit that smoothed the aerodynamics and saved weight.
D-Types fielded by a team under the leadership of Jaguar's racing manager Lofty England were expected to perform well in their debut at the 1954 24 Hours of Le Mans race. In the event, the cars were hampered by fuel starvation caused by problems with the fuel filters, necessitating pit stops for their removal, after which the entry driven by Duncan Hamilton and Tony Rolt speeded up to finish less than a lap behind the winning Ferrari. The D-Type's aerodynamic superiority is evident from its maximum speed of 172.8 mph on the Mulsanne Straight compared with the 4.9 litre Ferrari's 160.1 mph.
For 1955 the cars were modified with long-nose bodywork and engines uprated with larger valves. At Le Mans, they proved competitive with the Mercedes-Benz 300 SLRs, which had been expected to win. Mike Hawthorn's D-Type had a narrow lead over Juan Manuel Fangio's Mercedes when another Mercedes team car was involved in the most catastrophic accident in motorsport history. Driver Pierre Levegh and more than 80 spectators lost their lives, while many more were injured.
Mercedes withdrew from the race. Jaguar opted to continue, and the D-Type driven by Hawthorn and Ivor Bueb went on to win.
