The year is now 2015 and my car is approaching its “rolling chassis” stage – mirroring events of 50 years ago in Jaguar’s Competition Department. It was then 1965 and William Heynes, Jaguar’s Engineering Director still had hopes of seeing the car on track to contest that year’s Le Mans endurance race. Time was short but the skilled team working behind closed doors were used to working to such tight deadlines …
Let us go back a couple of years …
William (“Bill”) Heynes, Jaguar’s Engineering Director takes note of a change to the Le Mans regulations which now open the door to sports/racing prototypes of up to 5.0 litres (305 cu in) in capacity. No doubt, he smiled to himself as he was now in a position to bring a plan he had long kept in the back of his mind to the fore …
William Heynes of Jaguar
For Bill Heynes, racing engines had always been in his blood. Having left Humber in 1935 where he completed his engineering apprenticeship, Heynes joined William Lyons at SS Cars. Six months later he was working closely with and became one of the prime architects of an overhead-valve conversion for the Standard 6-cylinder engine. The first cars to have this engine installed were known as SS Jaguars. One of these first cars was the SS Jaguar 100. The power unit Heynes had a hand in designing soon powered this car to best performance in the 1936 Alpine Trial – showing these cars were more than just pretty faces.
Ten years later, Bill Heynes combined his talents with Harry Weslake, Walter Hassan and Claude Baily to produce Jaguar’s legendary and long-lived 6-cylinder XK engine – an engine which was to bring Jaguar success, not only in the showroom, but also in the highest-level of competition. Cars powered by these engines still dominate fields in historic racing today. After successes in the 1950s at La Sarthe with the works C-Types and D-Types, Jaguar switched their efforts to road cars and formally retired from racing in 1956 (although the factory continued to support private entrants).
Left to right: Walter Hassan, William Heynes and Claud Baily of Jaguar
Heynes did not disband Jaguar’s Competition Department and ensured its personnel remained intact after 1956. Key amongst these personnel were Malcolm Sayer who had masterminded the design of the highly-successful C-Type, D-Type and the E-Type prototypes. Another member of this select team was the South African Derrick Whyte, a talented chassis engineer who had cut his teeth at Connaught and became associated with their well-engineered, beautifully-built and superbly-handling cars. The third member of the team was Alex Frick whose expertise lay in tubular chassis frame design.
By 1963 Jaguar were on the brink of a return to racing with their Lightweight E-Types. However, the change in regulations for Le Mans in 1963 meant these beautiful cars would have been completely overwhelmed by the 5-litre prototypes now allowed by the regulations. The way was clear for Bill Heynes to carry out his plan for a full assault at Le Mans with a new mid-engined prototype sports car powered by Jaguar’s own 5-litre quad-cam V12 – an engine which was first and foremost aimed at racing with a possible secondary use in one of Jaguar’s future road cars. Unlike the XK 6-cylinder engine which was aimed fairly and squarely at road use and later modified for racing.
On 9th July 1965, Heynes despatched a young Mike Kimberley to Silverstone to see what he could learn. His brief? To brush up on the latest in Sports Racing Car design to see what the others were doing.
Fast-forward to 2010.
The story and fate of Jaguar’s car designed to carry out this assault at Le Mans is now well-known.
In short …
Only one car was built and circumstances conspired to prevent the car from ever turning a wheel in anger. Construction began in 1965 and the sole example built was completed in 1966. Its breaking of the UK closed-lap circuit record in 1967 in the hands of its main Test & Development Driver David Hobbs, showed its potential. This record was to stand until 1999 until beaten by a McLaren F1 road car.
Many myths and stories have been built up around this legendary car over the years. In recent years, exhaustive and comprehensive research by respected author Peter Wilson has established the facts surrounding this car – research which has been substantiated by interviews of those who were there as well as a mass of surviving contemporary documents and reports. Peter’s book “XJ13 – The definitive story of the Jaguar Le Mans car and the engine that powered it” provides a definitive record and builds on earlier writings from Jaguar historians such as Andrew Whyte, Paul Skilleter, Bernard Viart, Michael Cognet and Philip Porter.
The car underwent a series of clandestine but official tests arranged by its Project Manager Mike Kimberley (later to become CEO of Lotus Cars). Professional race-driver David Hobbs piloted the car in all official tests, supported by Norman Dewis and Richard Attwood. The one-and-only original was put under wraps in 1967 where it remained until 1971 when it was wheeled out to help publicise the forthcoming Series 3 V12 E-Type. The sad fate of the car in the hands of Norman Dewis is now well-documented. The car was crashed and its mostly-intact underlying structure was clothed in a new body fashioned by skilled craftsmen at Abbey Panels.
The sublimely beautiful lines of Sayer’s masterpiece were altered during the rebuild and the car remains in this altered form to this day. Regularly displayed at prestigious events the car forms a backdrop to Jaguar’s rich heritage and testament to the genius of Malcolm Sayer.
Many replicas of Jaguar’s current car exist although none have yet come close to capturing Sayer’s original 1966 form. Jaguar’s one-and-only altered original was digitally scanned recently and the resultant body is being applied to a GT40-inspired chassis which contains parts of an engine which, although never installed in a car in period, does contain surviving original prototype quad-cam components. This car, however, replicates the car as it stands today with its many differences to the 1966 original.
In 2010, I acquired the only surviving complete original prototype quad-cam V12 built to a specification similar to that of the engine which powered the original car in 1966. Four years of exhaustive and painstaking research have resulted in the accumulation of original and unique data for Jaguar’s original 1966 masterpiece.
What to do with this engine and all this data?
What would YOU do?
First of all, the following must be emphasised:
There is, and always has been, one Jaguar XJ13. The car is owned by the Jaguar Daimler Heritage Trust. Undoubtedly, their car is unique and has continuous history linking it back to the one and only original. It may have been described as a, “Jaguar-built replica” by authors Viart & Cognet in their 1985 book, “Jaguar – A Tradition of Sports Cars” (page 318), with forward by William Lyons himself, but this may be a little unfair as most of the underlying structure was salvaged and re-used. The engine installed in the car today is a different engine to the one originally installed in the XJ13 in the Spring of 1966 but it remains one of the very few prototype quad-cam engines that have survived and was installed in the car in period. OK, the body may be completely new, and different in some respects to the original body, but there can be no doubt that the car gracing the Jaguar Heritage collection can describe itself as the unique Jaguar XJ13.
What Neville is attempting to create can only ever be a facsimile and homage to the original XJ13 and its designer Malcolm Sayer. There is, and always has been, ONE Jaguar XJ13.
Four years of painstaking research – supplemented by interviews with those who were present at the time – resulted in a collection of data which could be used to precisely define the geometry and form of the original 1966 car. Having exhausted information available in Jaguar Heritage’s own archive, additional information was unearthed from records, photographs, reports as well as documentation passed down through the families of surviving relatives. This accumulated mass of data was combined by Neville using computer-aided design techniques to arrive at a digital model of the car and its underlying structure. This data includes the precise location of key mechanical and body components as well as suspension geometry as measured in 1966. The hope is that the finished recreation will duplicate the driving experience and characteristics of the original.
The prospect of actually driving the car under its own power for the first time is something which keeps me awake at night … 🙂
As time went on, both myself and the people entrusted with the build of my car came to respect the skills of the builders of Jaguar’s original XJ13 more and more. Without doubt, today’s use of computers and rapid-prototyping does make life easier. Wheras I was able to digitally model and “trial-fit” virtual components and body panels on a computer screen, these techniques weren’t available in 1964 and the builders of the original made do with “trial and error” as well as experience born from years of mastery of their craft.
In September of 1964, although there had been no official “go-ahead”, Bob Blake assisted by Geoff Joyce andRoger Shelbourne set about translating Malcolm Sayer’s hand-written data into wooden “buck” which could be used to shape the outer body skin.
Photo taken during the crashed car’s rebuild in 1972/73 showing the original rear body buck in the foreground.
The bucks (two in total – front and rear) were to be sent to Abbey Panels who would form the outer skins leaving Jaguar to fabricate the car’s monocoque/chassis. All they needed now was the formal go-ahead.
I followed a similar process – translating 3D data (and data derived from original technical drawings and photographs) into a “virtual” wooden buck which could be used to shape the outer body skin of my recreation. I was assisted in this process by CAD/3D specialists. Considerable work was needed to remedy shortcomings in the supplied buck by our first so-called “3D Specialist” to ensure faithfulness to the original car but we eventually ended up with something which could be used in the real world! To ensure accurate replication of details such as headlamp apertures, air scoops and windscreen surround, parts of the wooden buck had incorporated solid 3D sections which would be used as “hammer formers”. At this stage, the wooden buck only existed on a computer screen.
©Neville Swales – Digital representation of full-size body buck (third-scale model in foreground). Looks “pretty” but this is only a digital representation needing considerable work by skilled artisans for its use in “the real world”. NOTE TO SELF: Don’t be taken in by pretty digital images on a computer screen!
©Neville Swales – Close-up of actual buck.
©Neville Swales – Hammer-form nose-cone and headlamp 3D sections.
©Neville Swales – Nose-cone 3D section being CNC machined
Before this virtual buck was turned into reality, I digitally replicated the XJ13’s underlying chassis/monocoque and was able to virtually “trial fit” the body onto it to ensure everything was as it should be.
©Neville Swales – Trial-fitting virtual components
©Neville Swales – Trial-fitting virtual components
I was also able to add suspension components, engine, wheels and tyres etc to ensure everything would fit together without fouling when the digital model became reality. At this stage, it was possible to view the model from every possible angle as well as estimate things like final weight distribution, centre of gravity and the way light would catch the finished body surfaces. These are all things unavailable to Jaguar in 1964 and, instead, would have relied on trial-and-error as well as pure skill. The original builders were truly craftsmen.
Something which certainly wasn’t available to Jaguar in 1964 was the ability to print small-scale 3D models of the body before committing to buck manufacture. It is all very well being able to see things on a computer screen but being a bit “old school”, I didn’t feel comfortable giving the go-ahead to manufacture a full-size buck until I had something I could hold in my hand. Something which could be held and, in theory, be painted so the way it caught the light could be studied. I therefore commissioned a number of small-scale 3D-printed models to give himself greater confidence in the accuracy of the final body. 1/3rd and 1/6th bucks were also produced to show details which may not have been apparent at a smaller scale. These small-scale models did show some shortcomings in the digital data arrived at by my chosen 3D specialist and some manipulation of the data was required to arrive at something more satisfactory. I do recommend the use of 3D-printed models if you are considering taking the same path because things which can look “pretty” on the screen do not always translate ideally into “the real world”. It always helps to have something you can hold in your hand!
Finally, reasonably satisfied with the accuracy of the model, I gave the go-ahead for a full-size buck to be made directly from the CAD data – knowing that it could only represent a “guide” and the skills of the bodyshop would overcome any shortcomings. My faith in the skills of my chosen bodyshop (North Devon Metalcraft) proved to be well-founded.
Meanwhile, back at Jaguar, there was still no formal “go ahead” for the outer body skin to be made by Abbey Panels. The Competition Department staff knew that, if the car was going to be ready for the 1965 Le Mans, they really needed to get on with it. Derrick White pressed Bill Heynes but was told “not yet”. First signs of a lack of urgency around the project were becoming evident. Sadly, knowing what we do now, the best chance of a win at Le Mans would have been in 1965 – before Ford’s GT40 had got into its stride leaving Ferrari as the only serious competition.
As Peter Wilson reports in his book, “XJ13 – The definitive story of the Jaguar Le Mans car and the engine that powered it”,
“… as the surface plate we had in the Competition Department was not large enough, or indeed remotely suitable, Bob Blake, Geoff and Roger constructed a very rigid wooden platform on which to build the monocoque. This consisted of a cross-braced perimeter frame constructed from 9 x 3” timber, topped with ¾ inch thick plywood sheet. It was marked out with ’10 lines’ – lines 10 inches apart, either side of the longitudinal centreline, along the length of the platformand similarly in the transverse direction, from the front ‘zero’ datum point (the centreline of the front wheels). This would enable accurate referencing of each of the myriad of construction reference points defined by Malcom Sayer’s drawings.”
As a further means of ensuring accuracy of the replica monocoque, I turned to his computer again and commissioned a “monocoque buck” based on these reference points which would be precisely located in relation to the ’10 lines’. The originally supplied monocoque buck proved not to be fit for purpose and I commissioned a further buck to ensure faithfulness to the original.
©Neville Swales – Monocoque buck showing ’10 lines’ on baseboard
My chosen bodybuilders, Paul & John Evans of North Devon Metalcraft, used this monocoque buck to fabricate and build the front and rear suspension sections. Paul designed his own jigs to precisely locate all suspension components consistent with Jaguar’s original data.
Back in the January of 1965, Bob Blake made a start on the monocoque. At the time, it was believed that it was still possible to have the car up and running in time for Le Mans – although time was very, very tight. The hard-working members of the Competition Department were used to these tight deadlines. For example, work had started on the E2A E-Type Prototype in January of 1960. It was ready to run before the end of February and went on to race at Le Mans in June of the same year.
An XJ13 at the 1965 Le Mans was still a possibility.
The monocoque centre section consisted of the floor and outer sills. These were produced in two halves, as mirror-images of each other and joined along the centreline of the car using a double row of 3/16” dome-headed rivets. The sills had internal stiffeners and were roller-welded along their lengths. The Competition Department didn’t possess equipment to do this themselves so the entire assembly was shipped to Abbey Panels so they could be welded there. The welded sill sections were returned to Jaguar where bulkheads and door apertures were added. The team had been added to by that time by Denys Davies who assisted Derrick White with fabrication of detailed suspension components.
©Neville Swales – Original rear monocoque construction detail
©Jaguar Heritage – Original front monocoque construction detail
©Neville Swales – 2013 vs 1965
Paul & John at ND Metalcraft decided to fabricate a “prototype” sill structure in steel just “to get it right” before they fabricated the final version using the (rather expensive) original-spec aluminium.
©Neville Swales – Prototype all-steel monocoque on the originally-supplied monocoque buck (later to be replaced by a more accurate and usable item).
©Neville Swales – Prototype all-steel monocoque
©Neville Swales – Trial-fitting of front suspension on steel prototype monocoque
©Neville Swales – Prototype front suspension on steel prototype monocoque
©Neville Swales – Final monocoque – front suspension detail (NB original XJ13 does not have collapsible steering column section)
This steel prototype has since been destroyed and its place taken by the final aluminium version. As with the original, the front suspension consists of a steel framework riveted to the floor and front bulkhead. After many iterations and failed attempts by Derrick White to persuade Bill Heynes to use a state-of-the-art purpose-designed front suspension setup, Heynes prevailed and the XJ13 was fitted with a modified 1964 Lightweight E-Type front suspension as can be seen in the following picture:
©Jaguar Heritage – Front suspension detail – as 1964 Lightweight E-Type
I replicated the front suspension as far as I was able to arrive at the following:
©Neville Swales – Final monocoque – front suspension detail