Racing lightly on the track

Since Audi entered Le Mans prototype racing (LMP1) in 1999, the safety rules have never been as strict and race cars never as complex as this year. Designers – whether in production or race-car engineering – have to resolve target conflicts on a daily basis. However, the concept design of the new R18 e-tron quattro created a challenging requirement. The racing weight of LMP1 cars compared to last year could drop from 915-870kg, with 45kg making a big difference in racing. At the same time, new regulations had requirements that increased weight. For example, to protect the driver in the case of lateral impacts, the rules prescribed Zylon side panels. This tough and impact-resistant material prevents lateral intrusions of pointed objects in the cockpit in an accident. The monocoque itself was also redesigned to withstand higher test loads. The eight-wheel tethers (two per wheel), which prevent the separation of the wheels in accidents, were also new. The R18 e-tron quattro was equipped with a rear-crash structure made of carbon fibre-reinforced plastic (CFRP), which absorbs energy. The regulations permitted transmissions with seven instead of six forward gears. The new gear pair and its actuation made a difference on the scales as well, so engineers had to make the car lighter than before while achieving the lower minimum weight. Audi has consistently increased CFRP content. For the 2014 season, the steering wheel column of the sports prototype was made from this for the first time. However, it was banned in various areas. For instance, the wheel suspension elements still had to be made of metallic materials. Due to regulatory specifications and technical options, the room for manoeuvre becomes more constrained year after year. In spite of this, Audi achieved its target weight in the R18 e-tron quattro with the diesel hybrid meeting the 870kg limit. In total, the car is safer, lighter and more efficient than any predecessors, and Audi’s light-eight technology played a major part in this.