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Jaguar´s Winning Sports Car

Jaguar Heritage Magazine Issue Number 5

With the success of the XK120 in sporting events, Jaguar developed the model into a true competition car.

Three Jaguar XK 120s were carefully prepared by the factory and entered into the 24hour race at Le Mans in 1950. It was a reasonable success, one car held on to third place until the clutch expired just three hours from the finish. The two surviving cars finished twelfth and fifteenth.

William Lyons and William Heynes were delighted with the performance of the XK120 at Le Mans, but both men realised that it was never going to be competitive against pure sports-racing cars. They had to develop the XK120 chassis and the XK engine purely for competition work and return to Le Mans in 1951. However Lyons was not one to spend money unnecessarily and had to be convinced about the value of of a car dedicated for Le Mans the following year. Given the suffix C for competition, work began in secret on a lightweight XK120. Lyons himself designed a body that he thought would be ideal to clothe the XK10 chassis. This was made in model form but was not built. It shows that Lyons was not always right, but he knew that the correct the design was important, so he fully backed the version from Bill Haynes and Malcolm Sayer. However Lyons did ask for three lightweight XK120 bodies of standard shape to be made, in case the C-type was not ready.

Work Begins

Malcolm Sayer (1916-1970) had studied automobile engineering at university, but had joined the Bristol Aeroplane Company as an aero-engineer, the pay and prospects were better and here he was immersed in the world of aerodynamics. Following World War Two he left Bristol and worked for a time in Iraq before returning to Britain and applying for a job at Jaguar. He joined the firm in 1950.

Sayer´s background in motor and aero engineering was of great importance. He understood aerodynamics and their application to other branches of science. One of the first things he did at Jaguar was to install a wind tunnel, the first at Jaguar and start work on developing the concept XK120 C.

Sayer was tasked with designing a body that was aerodynamically more efficient than the XK120 but that could still be identified as being related to the Jaguar XK120. To save weight Haynes discarded the heavy XK120 chassis and adopted a multi-tubular space frame unit; Bob Knight, under Heynes´ direction, carried out the work. The foundation of the chassis was a drilled channel-section framework, but the strength lay in a triangulated box of tubes in the middle, with sub-frames carrying the engine and suspension in the front. The critical centre section, which contained the driver and passenger seats, was braced laterally, longitudinally and vertically. Sayer´s background in aviation can be detected here. Heynes retained the XK120 front suspension but the rear suspension was modified considerably. The half-elliptical springs were replaced by a single transversely mounted torsion bar, connected to the live rear axle by trailing arms, while torque reaction members prevented lateral movement. Rack and pinion steering was introduced, another first for Jaguar, in place of the recirculating ball type.

“We had about seven months,” recalled Heynes in later years, “to design, make and prove a car from a clean sheet of paper and to complete three cars for the race.” He went on to add, “We worked on drawings and models; we built up frames and bodies in wood and made use of broomsticks in the mock ups of the tubular frames.” At that time Jaguar did not have a dedicated competition department, so the design engineering and the experimental teams carried out the main tasks. The work on the XK120C was fitted into the normal working day alongside other everyday business.

“Everyone involved would work extra hours and week-ends to get the work done,” recalled Heynes.

Harry Westlake started with the standard 3.4 litre XK six-cylinder engine, retaining the wet-sump lubrication and the twin SU carburettors, but modified both the inlet port and the exhaust system. He also introduced high-lift camshafts and a lighter flywheel to boost the engine output to 210 bhp at 5,800 rpm (the XK120 engine offered 180 bhp at 5,300 rpm). The four-speed gearbox had ratios of 3.31, 4.51, 6.59 and 11.2:1 though closer ratios, including 3.99:1 third gear were later made available.

Testing Times

Small wooden models were made of the Sayer design and tested in the wind tunnel. As data was gathered the body was subtly altered and what emerged was a beautiful sleek purposeful sportscar. Although officially known as the XK120 ‘C’ the car was by now being referred to as the ‘Type - C’ and soon became the ‘C-type’ in the press. Abbey Panels, which had made the aluminium XK120 bodies, made the body panels for the C-type. The bonnet especially was magnificently sculptured. It was not simply a bonnet; it was an integral part of Sayer’s aerodynamically structured design. The early car had large side louvres which were later changed and it did not have any louvres on the top of the bonnet. That Jaguar had a potential winner in the making was only revealed to the public when a photograph and a description were published in The Motor for June 20th, 1951. Two days later more details appeared in The Autocar. So complete was the secrecy that nothing had leaked out about the C-type before this announcement. Le Mans was just a week away.

Testing of the first C-type, chassis number XKC001, was carried out at Silverstone and the MIRA test track. All the drivers, Whitehead, Walker, Moss, Fairman and Johnson were able to test-drive the cars. Only Clemente Biondetti, who was to share the driving with Leslie Johnson, was unable attend the testing. The three cars were completed in time and made ready for the drive to France.

‘Lofty’ England, Phil Weaver and Jack Emerson accompanied by tow mechanics, John Lea and Joe Sutton, drove the cars to Le Mans. A Bedford 13cwt lorry carrying spares escorted them. England said of the drive “We thought people should see that our cars were capable of being driven on the road, and if anything was going to fall off, then by the time you have driven across France on their bumpy roads, it would fall off. Much better to know before you start! Besides driving there would save money.”

Heynes arrived in a Jaguar Mark VII for the practice session and Lyons arrived after the start of the race by air in the Dunlop aircraft. Jaguar had arrived to do battle in one of the most testing of races with an untried car.

They were certainly the most modern looking of the 1951 entrants, but were not regarded as a threat. Aston Martin had entered five cars; there were six 4.5 litre Talbots and Ferraris also on the grid. Briggs Cunningham had brought two of his big 5.4 litre Cunninghams to Le Mans; so what could the untried 3.4 litre XK- powered C-type accomplish?

It was only during practice that the C-type threat could be measured. Peter Walker, driving XKC 003 averaged 104mph (167.4km/hr) in the dark at a mid-week session. However, there were problems. C-type XKC 001 suffered engine trouble and had to be rebuilt by Jack Lea; the Marchal headlamps proved inadequate and more powerful examples were ordered. This required the manufacture of the new backshells to accommodate them. Lofty, Heynes and Weaver set about making repairs to Moss´s C-type when he struck the rear end of Morris-Goodall´s Aston Martin during the Thursday night practice session.

Le Mans

At four o´clock on Saturday June 23rd, 1951, the race began at a wet and overcast Le Mans. Stirling Moss, Peter Walker and Clemente Biondetti sprinted to their cars and were away. By the end of the second lap Moss was second to one of the big Talbots driven by Gonzalez from Argentina. After three more laps Moss was in first place with Biondetti moving into third position. After five more hours Moss was still leading with the Walker/Whitehead and Biondetti/Johnson C-types in second and third places. Moss also shattered the lap record at 105.2mph (169.3km/hr) taking 4 minutes 46.8 seconds. All looked good for the Jaguar team and then Biondetti noticed a drop in oil pressure. He stopped at the pits and oil was found in the sump but none was being circulated to the engine. Nothing could be done, as the rules at the time only allowed the use of tools and parts carried in the car. So the C-type had to be retired. Moss/Fairman and Walker/Whitehead were still in first and second places.

The cars appeared to be going well, but then on lap 94 Moss suffered the same fate as Biondetti and ground to a halt with a broken con-rod after Arnage corner. It appeared that a weld on the main oil feed pipe had broken due to engine vibration. Only one C-type was still in the race and took the lead but it could still go the way of the other cars. Peter Whitehead and Peter Walker were instructed to keep engine revs down and drive as smoothly as ossible. This they did and the Jaguar performed faultlessly during the following laps. Peter Whitehead drove the final phase and took Jaguar XKC 003, race number 20, to victory. The car was 45 minutes and 77 miles (124kms) ahead of the Talbot that came in second. The Jaguar C-type had covered 2,243.886 miles (3,611.085 km) at an average speed of 93.495mph (150.461km/hr)

Before the win at Le Mans Jaguar was a small, relatively unknown manufacturer. After the win the name was known worldwide. It was publicity that simply could not be bought. Jaguar sales increased substantially as a result. As Lofty commented a few years later. “As soon as we won Le Mans people knew what a Jaguar was and the name went forward very, very quickly.”

Building on the success at Le Mans, Jaguar entered the C-type in other events that year. At the Tourist Trophy race at Dundrod in Ireland the three cars were entered. The copper oil delivery pipes that had been blamed for the troubles at Le Mans were replaced with steel ones. Stirling Moss, driving XKC 002, took first place at an average speed of 82.55mph (132.847km/hr). Second place was taken by Leslie Johnson and Tony Rolt took fourth position. The C-types were awarded the Team Prize.