Carbon fibre efficiency

Carbon fibre efficiency

The Ferrari F138 and Luna Rossa AC72 catamaran share more than good looks and Italian style. One magic ingredient, carbon fibre, has become the essential material for victories both on land and on sea

Estimated reading time: 9 minutes

The history of composite materials began very early… this may sound silly, but one of the first examples of the combination of a fibre with a matrix or resin was found in primitive mud and straw huts. The fibre is the part with the best mechanical characteristics, while the matrix holds the structure together. Today, we use composite materials extensively even if the term tends to refer to the higherquality, more expensive part of this construction technique. Fibreglass is the best known type and the one most commonly used in various forms. With carbon fibres and epoxy resins, you can build with the best mechanical characteristics, whether with a single “skin” and a number of layers, or by using the “sandwich” technique, placing a neutral layer (a light material to create a thickness) between two surface skins. Carbon fibre is used to build aeroplanes, cars and boats.

Today, carbon fibre is used to build most of the single-seaters
It was first used in the 1980s, most famously with the construction of the invisible Stealth aircraft. The Ferrari F138 and Luna Rossa, which is challenging for the America’s Cup for the fourth time, are both almost completely built in carbon fibre. However, there is one basic difference between the two even if thetechnologies in the use of these materials are closely related: Ferrari creates cars at its own plant in Maranello, while Luna Rossa Challenge uses external suppliers, notably the Persico shipyard. As Rory Byrne, the celebrated Ferrari designer and a key figure behind all those title-winning Prancing Horse F1 cars during the Michael Schumacher era, explains: ‘The first car with a chassis built entirely of carbon fibre was the McLaren in 1982. From then on all the teams have adopted it and there have been continuous evolutions. Today, carbon fibre is used to build most of the single-seaters, replacing titanium, which had been an important material for many years and is now used only when necessary.’ What do cars and boats have in common? ‘Carbon fibre has the right response when what is needed is maximum rigidity and resistance with minimum weight. Carbon fibre is a supple material, which can be moulded into any shape, with advantages in everything from aerodynamics to aesthetics, because it allows every solution.’ Byrne’s response backs up a view shared by the other designers.

It is interesting to note that, in the early 1980s, the composite technique was more widespread in boats than in cars and contributed to the progress of performance in the two sectors more than in others. At Ferrari, the level of sophistication in the use of fibre is evident in the new LaFerrari, where fibre is used that has different characteristics depending on the type of stress to which the part is subjected (just as happens for the unitised body of the F1 car). Roberto Biscontini, a naval architect on the Luna Rossa design team, takes us back in time: ‘I find it fascinating to highlight how, even with incredible technical evolution, we keep borrowing structures from nature. After all, the philosophy of a piece of carbon laminate is not very different from a piece of wood: there are fibres that are unidirectional and hollow, with the advantage that carbon fibre can take on any shape we wish to give it. ‘This return to shapes developed in nature is not haphazard; the evolution of so many millennia has a significance. Even in our calculation procedures, in order to save time, we use what is called the Genetic Algorithm, because it simulates the decision-making mechanisms of the process of evolution with a comparison of elements that I would define as similar to the law of nature, where what works is always conserved. With the current power of calculation in just a few days we can simulate processes that took millennia.’ The differences between cars and boats are fewer you might think, even though cars move on asphalt, where the reactions are known, and the sea is less predictable and creates extraordinary events that can quickly become dangerous. Byrne adds: ‘It is interesting to note that, though moving in a different system, with us on land and boats on water, we need fluid dynamic systems that resemble each other; by using wings in cars we seek the ground effect to cling to the road, whereas in boats it is the lifting effect that is needed. It is a matter of looking for compromises with speed.’ Special boats have been chosen for the next America’s Cup; catamarans of around 22 metres that have the capacity to rise above the water, “flying” like hydroplanes.

Carbon fibre has the right response when what is needed is maximum rigidity and resistance with minimum weight
This radically changesthe resistance and therefore their power: these boats reach record speeds that have until now only been achieved by craft built to beat records and sail faster than 40 knots, which is a little less than 80km/h. Not very fast compared to performance on land, yet an enormous speed when sailing on water. While on the road speed depends on the power of the engine and a series of other fixed parameters, at sea the maximum speed is associated with the wind strength. The stresses on the structure and the dangers also increase. And then the wind is not the same for everyone: even at a distance of a few dozen metres it may blow differently for two competitors, in terms of both speed and direction. In addition to knowing how to exploit the vessel to its limits, as F1 drivers do, the helmsmen must also know how to steer the boat where the wind is best. Having this kind of insight often creates ahuge advantage, hence the need for a back-up team of tacticians and navigators. Corrado Lanzone is the Head of Scuderia Ferrari Production: ‘Not only do we build the parts of the car, we also create the material used to build them, which is a combination of fibre, not just carbon fibre but also Kevlar, Zylon and resins with various characteristics. Beyond mechanical qualities, the problems we have to resolve also concern the resistance to high temperature in the proximity of the engine and a series of specifications required by the regulations for the reinforcement parts on the sides. The major breakthrough in carbon fibre use occurred when we began to build the small parts; the suspension arms are perhaps the most obvious thermometer of this evolution and have now lost all their metal parts. The future could be in Graphene, a one-atom-thick carbon sheet.’ The state of the art in cars has been achieved in the gearbox housing; this is a special part, complex and fundamental, where, due to heat expansion, the metal parts are reduced to being just the support for the ball bearings. Biscontini explains: ‘Unidirectional fibres have significantly changed our way of making these items; orienting the fibres means not only that the piece is lighter, but also that it breaks less often. Over the years there has been an important evolution; the boats are better. They have sometimes failed, as in the round the- world race, but this has happened under extreme conditions. The catamaran for the America’s Cup was built without previous experiences and did not break because, with engineering and the structural research we came very close to achieving the optimum resultconceived on the drawing board.’ The crucial points for the boats’ performance are the structure of the foil, the daggerboards and their tuning systems. Tiny adjustments are enough to go fast or slow, an important part consists in learning how to use the boats.

Matteo Plazzi, Thomas Gaveriaux and Will Brooks are the heads of construction for Luna Rossa. They stayed in Auckland for the launch and the first trials of Luna Rossa, which was completed, assembled and launched in New Zealand. Plazzi, who as navigator of Oracle BMW is one of five Italians who have won the America’s Cup, explains: ‘I see a major difference between the two worlds in the dimensions of the structure and in the timescales devoted to research, development and construction; all this obviously affects the strategic decisions. In an America’s Cup cycle we build one or at most two boats, with a construction time of at least 20 weeks; we cannot devote huge resources to the small pieces and we focus on the fundamental structures. In F1 much more time is devoted to research and more accurate tools can be employed to make pieces in the autoclave. Thus the engineering time devoted to the details becomes an important variable.’ Gavireaux adds some more detail about the material: ‘There are two elements where carbonfibre is used best for its characteristics; they are the structure of the foil, which is a truly impressive piece, and the daggerboards, which take all the strain when the boat takes off [foiling], with around seven-and-a-half tons of vertical load and three and a half lateral; the internal loads of the structure reach over 300 tonnes.’ The daggerboard is actually no more than a metre wide, and minor variations in its incidence on the water are decisive. The foil is 38 metres high and weighs 1325 kilograms; inside there is a complex structure that “twists” it to change its profile. Brooks adds: ‘I think that, more than in carbon fibres, the future development of our technologies lies in the resins and manufacturing process and that there is scope to use nanotubes.’ We are entering the territory of nanotechnologies, a way of giving a direction to the structure and the fibre, as always saving weight. As Ferrari and Luna Rossa show, carbon fibre remains a common denominator for high technology objects, and its methods of use reveal a grammar underlying a common language, built in the name of performance. And now, with the new LaFerrari, it leaves the track and regatta courses and encounters an elite public that can savour the symbolic and concrete meanings of this magical fibre. The Reds win… with black.

 

Da issue n° 21 May 2013

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  • Antonio Levatino

    I look forward to to further use of CF by Ferrari!

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