Revolutionary Technology in Formula One: The Monocoque Chassis

For a long time in the development of the automobile, it was common to build a car by fitting a separate body to an underlying rigid frame in a method called body-on-frame construction. While this technology had some advantages, such as the easy development of custom bodywork by coachbuilders, there was much left to be desired. With all of the torsional and bending strain placed on the rigid frame, it was necessary for this component of the car to be heavy and cumbersome in order to be strong enough to provide sufficient resistance against forces.

The earliest Formula One cars, such as the pre-war voiturettes of 1950 and 1951, were built on ladder frames, where the rigid frame only made up part of the bottom of the car, and the rest of the bodywork provided no structural support at all. This was quickly replaced with a more advanced chassis type when the sport moved to Formula Two rules in 1952. The spaceframe chassis, which was used on cars from the dominant Ferrari 500 of 1952 and 1953 to the Ferraris, Coopers, Lotuses and BRMs of the early 1960s, was based around interlocking struts placed in a geometric pattern around the body in such a way as to place the strain of torsion and bending all over the car.

Surprisingly for the top echelon of formula racing, though, spaceframes were old technology. The Second World War had necessitated a lot of technological and mechanical development in aircraft, and the improvements made in that field filtered down to car design in the post-war years. In the run-up to the war, the British, French and German air forces had independently designed fast interceptor fighter aircraft built on monocoque fuselages. The monocoque itself was not a particularly new idea, dating back to some reconnaissance aircraft of the First World War, and had been trialed in several pre-war car designs including the Lancia Lambda and the Citroën Traction Avant.

By the time Colin Chapman, owner of Team Lotus, designed his own monocoque Formula One cars, the technology had found its way into several commercial road-going vehicles, such as the Morris Minor and Chapman’s own Lotus Elite. It was therefore well-known that monocoque design provided substantial advantages over a ladder frame chassis in road cars, but it was yet to be demonstrated that these advantages would be worth the effort in Formula One racing.

Colin Chapman was known for his famous statements on car design, apocryphally stated as “Simplify, then add lightness”. Chapman, who had briefly been a pilot in the Royal Air Force, maintained a deep interest in aeronautical engineering techniques for the rest of his career in car design. Monocoque chassis use the body of the car as a supporting member in conjunction with the chassis, greatly increasing rigidity and therefore structural integrity. When Team Lotus introduced their Lotus 25 in 1962, the car was significantly lighter than its competitors and became the first of Lotus’ many successful Formula One models.

In fact, the Lotus 25 almost won both the Drivers’ Championship and the International Cup for F1 Manufacturers on its debut in 1962, but an engine failure for Jim Clark in the last race gave the championship victory to Graham Hill, driving for BRM with a more conventional spaceframe car. The results of the 1962 season underlined a weakness of the design characteristics of Team Lotus; while Graham Hill was classified at the end of every race that season, Jim Clark, despite his smooth driving style, had retired four times. The Lotus 25 was mechanically unreliable, and perhaps under a more leaden foot than that of the preternaturally talented Clark, the car may not even had made it that close to the championship that year.

That said, the car was clearly quick, and after the disappointment of the year before, 1963 would prove a change of fortune for Clark and Team Lotus, taking both championships convincingly against competition which persisted in using their spaceframe cars from the previous year. The advantages of the monocoque design had been clearly demonstrated, and another garagiste team joined Cooper in the annals of Formula One history.

Unfortunately, Jim Clark and Team Lotus were unable to repeat the feat in 1964. Ferrari and BRM, Lotus’ biggest competitors, had caught up technologically and built their own monocoque cars, and this combined with the Lotus 25’s recurrent unreliability left Lotus floundering at the end of the year. They would come only third, while John Surtees would secure the title for Ferrari after a year-long battle with Graham Hill in his BRM. Yet, by the time the Lotus 25 was replaced by the Lotus 33 a few races into the 1965 season, it had revolutionised the way that Formula One cars would be built in the future. The monocoque chassis is universal among modern Formula One cars, along with its near-universal presence in road cars.

However, there would be a few last significant demonstrations of spaceframe design in Formula One, taking place during the 1966 and 1967 seasons, where the increase of engine power from the new 3-litre engine formula gave the advantage to those who could acquire a reliable engine. Jack Brabham, having won the 1959 and 1960 Drivers’ Championships in mid-engined Coopers, had set up Motor Racing Developments, better known as Brabham, and chose a high-torque, lightweight aluminium engine from the Australian engineering company, Repco. This engine, which would prove the class of the field even with a deficit of power versus the Ferrari and Honda V12s, was allied to a conservative series of designs by Ron Tauranac, who still preferred the spaceframe.

There was one advantage of the spaceframe design which was of significance to Jack Brabham – it was easier to repair than a monocoque design, as a piece of tubular frame could be cut out and replaced a lot quicker than having to remove a whole section of body and weld in a replacement in such a way as to retain structural integrity and strength. Yet, in a season of unreliability, this was a secondary issue compared to the temperamental new engines used by most teams. Despite the dated design of his Brabham BT19, Jack Brabham would win the 1966 Drivers’ Championship with superior reliability and a run of four consecutive wins.

This was followed up by another Drivers’ Championship victory in 1967 for Brabham’s team, this time for Denny Hulme, but by the time 1968 came, other teams had caught up in the engine race, most significantly Team Lotus. Their assistance in the development of the Cosworth DFV had given them access to the engine which would dominate the next two decades, while the Repco engine didn’t cope well with additional power. By 1970, even Tauranac had conceded to the monocoque. Meanwhile, this would merely be the first in a series of innovative solutions from the mind of Colin Chapman.

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5 Responses

  1. I like this article but I was expecting more of a description of the advantages of the monocoque type chassis besides less weight and load bearing designs. Nice background though

    • Given the proportion of my traffic which comes from this article, I think I’ll have to do a proper comparison of monocoque chassis versus other types fairly soon, if only not to disappoint everybody that reads the article.

      • There’s not a lot of material available that compares monocoque chassis versus other types so it would be good to get your perspective on the subject. From reading this particular article I can tell that you too appreciate detail so whenever you do write a comparison I think you will not disappoint. Thanks for the response!

  2. […] The Monocoque Chassis – A Technophile’s IndulgenceRevolutionary Technology in Formula One: The Monocoque Chassis. Posted on September 16, 2011 by rakanalysis. For a long time in the development of the … […]

  3. Respected dear friends ,
    Greetings !
    A monocoque bus is much better than convensional bus .
    Like :
    ! . Lighter in weight .
    2, More impact strength .
    3 . Easy to fabricate .
    4. Less fuel consumtion .
    etc..
    Regarsd ,
    Kalsi

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