AUTO HISTORY
Auto historian Bill Vance recounts the saga of one of the world’s most prized automobiles, the D-Class Jaguar that ruled the 24hour race at Le Mans during the 1950s.
The highly regarded English Jaguar, now owned by India's Tata Motors, had pretty humble roots. It began in 1922 when two young Blackpool motorcycle enthusiasts William Lyons and William Walmsley established the Swallow Sidecar Co. to build zeppelinshaped, aluminum-clad, motorcycle sidecars.
They advanced to customizing Austin Sevens and others and relocated to Coventry where they were soon building whole cars called SSs using Standard Motor Co. chassis and engine. The Jaguar name appeared in 1935.
Following the Second World War the SS name had become toxic so the company was renamed Jaguar Cars Ltd. It continued building pre-war designs while developing new models, the first being the XK120 Roadster introduced in 1948.
The XK120 was stunning in appearance and performance, and while intended for touring not racing it was soon being campaigned. The factory even entered a three-car team in the Le Mans, France 24-hour race in 1950. Although not expecting to win it demonstrated enough potential to convince Jaguar to develop a competition model. This resulting C-Type would be an attempt to return Britain to its Le Mans glory days of Bentley’s five wins in the 1920s.
The C-Type with styling by aerodynamicist Malcom Sayer fulfilled Jaguar's hopes by winning Le Mans in 1951. It returned in 1952 with a new long, aerodynamic nose and smaller air intake. Unfortunately insufficient air entered, causing overheating which forced the entire factory team to retire early. First and second places went to the sensational new Mercedes-Benz 300SL coupes.
Jaguar brought the regular nosed C-Types back for 1953 with a new secret weapon: disc brakes which allowed drivers to go deeper into corners before braking. It was the decisive factor and Jaguars finished first, second and fourth.
In spite of the C-Type's success, competition from such marques as Ferrari, Cunningham and Aston Martin was getting stronger and Jaguar knew it would need a new design to remain competitive.
The result was the 1954 D-Type. Whereas the C-Type had a multiple steel-tube space-frame, the smaller D-Type had a monocoque body with the light alloy skin panels contributing to overall stiffness. A square-tube aluminum space frame carried the engine, front suspension and rack-and-pinion steering, and a rear one supported the spare tire and fuel tank.
Front suspension was independent with A-arms and longitudinal torsion bars while at the rear was a beam axle and single lateral torsion bar anchored in the middle. The rear axle was secured by four trailing arms and a vee-shaped frame attached to the body. A large fin behind the driver improved directional stability.
Power came from the XK120's sturdy double overhead cam 3.4litre inline six with horsepower increased to 245 from the XK 120's 160; it would ultimately reach over 300. For a lower profile the engine had dry sump lubrication and was tilted eight degrees to the right. It drove through a new four-speed, allsynchro manual transmission.
In spite of only three months' development time for the 1954 Le Mans the D-Type came in second between the winning 5.0litre Ferrari V12 and the third place 5.5-litre Cunningham V8. The D-Type suffered fuel filter clogging from a batch of dirty gasoline.
Then began the D-Type's Le Mans glory years. With a 190 mm (7.5 in.) longer more aerodynamic nose it finished first and third in 1955, first in 1956 and first, second and third in 1957.
The factory dropped out of racing in 1956 but the Scottish Ecurie Ecosse team continued racing the D-Types. It would score many more victories both in Europe and America, but its pinnacle was Le Mans, the race for which it was designed.
How fast was the D-Type? During the 1954 Le Mans race Stirling Moss reached 278 km/h (173 mph) on the long Mulsanne straight.
On regular roads Road & Track (5/56) reported zero to 97 km/h (60 mph) in 4.7 seconds and zero to 161 km/h (100 mph) in 12.1 seconds. They recorded a top speed of 261 km/h (162 mph) in the California desert, remarkably good performance even 60 years later.
Although the D-Type was designed for competition Jaguar did produce some 67 dual purpose versions for those hardy types who wanted one for racing and highway use.
There was also a more civilized road-going sports version called the Jaguar XKSS spun off the D-Type. It was fitted with a wider cockpit, proper windshield, bumpers, a rudimentary folding top and luggage rack (the trunk was full of fuel tank and spare tire). The stabilizing fin and driver's headrest was removed.
With its three consecutive Le Mans wins the Jaguar D-Type gave Britain its finest hours in international sports car competition, making it a truly iconic car. It was also the inspiration for the beautiful Jaguar E-Type production car.