Inside Revolution: Celebrating the Jaguar D-type
With car values now measured in millions for cars with strong provenances, D-types are still raced, albeit sparingly, in prominent historic races across the world. Notably, Goodwood and the Le Mans Classic are high on the agenda for racing owners, while the Woodcote Trophy series from Motor Racing Legends is another platform for these exquisite sports-racers.
Back in 1954, Jaguar unveiled the D-type to an appreciative audience as the British challenger to Ferrari and Mercedes in the new World Sportscar Championship. The D-type took over from the C-type, or XK120C, which was twice a winner at Le Mans in the early 1950s.
The D-type design drew considerably from aeronautical engineering expertise. Importantly, the sleek D-type broke new ground in using a monocoque construction, rather than the spaceframe that had become the accepted norm for racing car manufacture.
The monocoque construction used sheets of aluminium alloy to form the central tub, which included the cockpit. The D-type was the first Jaguar, and one of the first racing cars, to use a monocoque and the early cars had a front subframe welded to the monocoque. On later cars the subframe was bolted to the monocoque.
The subframe carried the engine, suspension, and steering, while the rear suspension and differential were mounted directly onto the tail of the monocoque. Another innovation was the use of deformable bag tanks for the fuel, with fuel cells incorporated into the monocoque.
Though there was much that was new about the D-type, several concepts were successfully carried over from the C-type, including disc brakes and the well-proven XK engine. However, the engine was developed to suit the new model, for bodywork expert Malcolm Sayer, drawing on his aviation experience, required a very low frontal area for the D-type.
To drop the height of the XK engine, a dry-sump oil system was designed, and the engine was installed at eight degrees to the vertical. The result was a considerably lower frontal area, capped by the trademark off-centre bulge in the bonnet to accommodate the top of the engine. At its highest point, the D-type stood just 32 inches tall.
With the top speed at Le Mans firmly in mind, Sayer also paid attention to the underneath of the car and created a low-drag floor. Finally, in a bid to increase high speed stability, and in response to wind-tunnel testing, a large vertical fin was added behind the cockpit. The car was designed without compromise to continue and further enhance the Jaguar brand as it took on the world. Victory at Le Mans was the target for it would carry huge marketing and advertising value for the brand. A whole season of work and development focussed on that Le Mans win, the single most important event on the racing calendar.
With the horror of World War Two less than a decade past and the privations of rationing still fresh in the nation’s memory, the D-type became a motor sport success story that captured the heart of the nation. The car was automotive beauty, and the drivers were heroes at a time when austerity remained a key part of everyday life. Yet, ironically, it was a small private team based in an Edinburgh Mews that brought the D-type the success it truly deserved.
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