Jaguar D-Type

Lore & Background

Engine displacement began at 3.4 litres, was enlarged to 3.8 L in 1957, and remained at that size for the D-Type's Le Mans career; the 3.0 L rule introduced in 1958 did not affect the D-Type, as no D-Type raced at Le Mans that year. D-Types won Le Mans in 1955, 1956 and 1957. After Jaguar temporarily retired from racing as a factory team, the company offered the remaining unfinished D-Types as street-legal XKSS versions, whose perfunctory 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 production is thought by some to have totaled 71 D-Types, including 18 for factory teams and 53 for privateers (this count includes 16 D-Types that were converted into road-legal XKSS versions). Jaguar is quoted as claiming it built 75 D-Types.

In Their Own Story

The sun beats down on the Mulsanne Straight as the roar of the XK engine echoes off the trees. Inside the cockpit, Roy Salvadori grips the wheel, his eyes fixed on the distant horizon where the Mercedes SLR is a fleeting shadow. The air inside the cockpit is thick with heat and the smell of high-octane fuel. As he approaches the first corner, the car's long tail slices through the wind effortlessly, a testament to Malcolm Sayer's genius. It is not just speed that wins here; it is endurance, precision, and the sheer will to push the machine beyond its limits for twenty-four relentless hours.

Reader's Guide

The design applied aeronautical technology, revolutionary at the time. 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 influence and overall body design was 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. The D-Type required a minimal frontal area. To reduce the XK engine's height dry sump lubrication was developed, 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 '[a] 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. Mechanically, many features were shared with the outgoing C-Type. Its front and rear suspension and innovative all-round disc brakes were retained, as was the XK engine. Apart from the new lubrication system, the engine was further revised as development progressed during the D-Type's competition life. Notably in 1955, larger valves were introduced, together with asymmetrical cylinder heads to accommodate them. Elements of the body shape and many construction details were used in the Jaguar E-Type from 1961 to 1969.

Did You Know?

• D-Types won Le Mans in 1955, 1956 and 1957.
• The 1956 Le Mans winner was a D-Type entered by Ecurie Ecosse and driven by Ron Flockhart and Ninian Sanderson.
• Mercedes-Benz withdrew from motorsport after the 1955 Le Mans disaster, so there was no German factory opposition in 1956.
• In 1957, Ecurie Ecosse finished first and second at Le Mans, the best result in the D-Type's racing history.
• A 1955 D-Type sold at auction in 2016 for $21,780,000, the most expensive Jaguar ever to sell at auction.