Motorsports: a sure-fire win for composites

Carbon and resin sail to victory…

The Vendée Globe, the solo round-the-world sailing race, is in full swing! Since the first edition held in the late 1980s, the time spent at sea by the winner has dropped from 109 to 74 days! Although sailors are now better prepared than ever, this alone does not fully explain such an improved performance. Other likely candidates for the improvement include the design of the boats and the evolution of the materials used. In these fields, the appearance of foils was a real revolution, to the point that some of the ships are even called flying boats!

Carbon and epoxy resin foils now make it possible for sailboats to literally fly.

However, the description is more than just fanciful imagination. The foils are designed like aeroplane wings placed perpendicularly to the water’s surface on each side of the hull. They cause the hull to lift out of the water when the boat gains speed. The ship thus displaces less water and can therefore gain speed to the point where it can move faster than the wind. The concept of foils first appeared in the 1970s and they have long been used on many passenger motorboats. The most famous of these are found in Hong Kong Bay. Their foils are made of steel, a very strong but also very heavy material. Not too much of a problem when you have powerful engines to do the heavy lifting.

So why did it take almost 50 years for foils to become a common sight on ocean racing yachts? And why talk about a revolution? Quite simply because the right materials were not yet available. In order to be efficient, a racing boat must be light; this means that steel could not be used for the foils. The first tests were carried out in the 1980s using aluminium, a lightweight material whose flexibility unfortunately cancelled out the desired effect. Fibreglass and epoxy resin were on the right track, but still too heavy.

Then came carbon fibre, an extremely high-end material in the 1980s and 1990s. Since then, carbon fibre has become more affordable and its complexities have been mastered. Resins based on liquid thermosetting polymers, such as epoxy, have a lot to do with this, as they are increasingly less difficult to use and no longer need to be heated to high temperatures to be moulded. Because carbon fibres are fairly strong and very lightweight, they can be used to fulfil the wildest ambitions of naval architects and skippers alike. As a result, the round-the-world sailing record for crewed and multihull sailing is currently 40 days, and the pure speed record is over 120 km/h. This level of performance was unimaginable just 10 years ago. Even Jules Verne couldn’t have predicted that.

Whether they are intended for yachting or regattas, sails have long been made of synthetic materials such as polyester or PBO.

In the same field, it would be unfair not to mention the performance of the sails which, in the Formula 1 vehicles of the seas, are made of fibres of PBO (Polybenzobisoxazole), a polymer that does not deform, better known as Zylon®. Competition-grade sails are now made of this fibre, sometimes pre-impregnated with a thermosetting adhesive to give them rigidity or even encapsulated between two Mylar© films. Glued or even moulded, they are above all designed to have a real aerodynamic profile, like a vertical aeroplane wing.

Coal in the machine! From one Formula 1 to another, there is only a short step between the two. The performance of the original kind, those that race on circuits, also owes a lot to polymers. The racing cars are also carbon-coated and have been so for much longer than boats. However, the budgets are not the same. 85% of the parts on the racing cars are made of polymer composites. The reason for this is always the same: weight-reduction, a constant in this field! Although the first F1 cars were made of steel, aluminium quickly became the preferred material, making the vehicles about 30% lighter.

Fibreglass and epoxy resin then appeared in the 1980s. The weight reduction was minimal but the ease with which this composite could be moulded made it easier to profile the parts, improving their aerodynamics. Then came the time of carbon. Ultra-strong, easily mouldable, ultra-lightweight, resistant to wide temperature variations... it is the king of all composite materials. It has become so ubiquitous that parts manufacturers have been investigating new techniques to further improve its moulding. Thus, they now manufacture laser-engraved polyurethane and epoxy resin moulds. This technique is close to 3D printing and enables them to quickly make custom moulds. It is using this technology that bucket seats, in particular, can be designed to be perfectly adapted to the morphology of the drivers. As a result, these cars were achieving such heights of performance that the International Motor Sports Federation decided to restrict their use because the safety of the drivers was at stake. The record of 378km/h will therefore not be broken any time soon.

Plastics take to the skies

After sea and land comes the air. Here too, polymers contribute to the most incredible records. We have all seen those daredevils jumping from cliffs and hurtling through the air wearing only their wingsuit. This wingsuit is a flexible suit shaped like a wing that increases the glide ratio and therefore enables the wearer to fly further and for longer periods. It is a clever combination of nylon®, a polyamide, and elastane marketed under the name Lycra®, an ultra-elastic polymer textile. Nylon® was chosen for its resistance to friction and because it can withstand the air pressure during flight without issue. As for the Lycra®, which is sometimes reinforced with polyester parts, its elasticity enables the wearer to retain control of their movements, especially during landing.

Fitting electric motors to a wingsuit was quite the challenge. BMW did it and the parachute test pilot reached a speed of 300km/hour.

The best flyers very often exceed 100km/h. However, the speed record was literally shattered in November 2020 and it is all down to car manufacturer BMW. The company, in a desire to demonstrate its mastery of the electric motor, designed just such a motor small enough to fit into a wingsuit. The system delivers a total power of 15 kW thanks to its two 7.5 kW fully carbon and resin turbines. The wingsuit was developed over the course of 3 years.

And it was a success, as parachute test pilot and professional base jumper Peter Salzmann reached a speed of 300 km/h in horizontal flight after jumping from a helicopter at an altitude of 3,000 m. As for the descent speed record, it was 400km/h and was beaten by Fraser Corsan who jumped out of a plane at an altitude of 11,000m.

Polymers in search of open spaces

If there is anyone who could be described as a daredevil, that person is surely Austrian national Felix Baumgartner. In October 2012, he made a parachute jump from space or more precisely from an altitude of 39 km. In making this jump he broke many records, including the highest parachute jump, the longest free fall and the first human to break the sound barrier in free fall. This feat was made possible thanks to the quality of his equipment and his team of scientists and engineers. Their missions: to design a transport capsule - a suit capable of resisting this fall of more than 4 minutes with a peak at 1,173 km/h, a parachute to slow the fall, and a balloon enabling it to reach the frontiers of space. While the capsule's frame was made of steel, its envelope was a sphere of fibreglass and polymer resin, a very strong material that was sufficiently insulating to ensure the parachutist was protected in the stratosphere. Felix Baumgartner was equipped with a pressurised suit designed to protect him from temperature variations ranging from -65° to 40°C. The David Clark Company, the manufacturer, remains tight-lipped about its composition, but it is a safe bet that it was strongly inspired by the space suits developed for NASA, which comprise a plethora of polymers such as Nylon©, Lycra©, polyester and even Mylar© and Kevlar©. As for the helmet, it was an assembly of different composite materials (that is all we know) chosen for their light weight and resistance to impact. The last component was the helium-filled balloon that enabled the capsule to reach the gates of space. It was made of strips of high-performance polyethylene film, a material barely 0.0002 mm thick.

39km of altitude, breaking the sound barrier… Felix Baumgartner’s jump beat many records. Polymers had a hand in those achievements.