The Role of Aerodynamics in the 1955 Le Mans Crash

Paper i proceeding, 2008

In the 1955 Le Mans race the worst crash in motor racing history occurred and this accident would change the face of motor racing for decades. After the crash numerous investigations on the disaster were performed, and fifty years after some interesting books were launched on the subject. However, a number of key questions remain unsolved; and one open area is the influence of aerodynamics on the scenario, since the Mercedes-Benz 300 SLR involved in the crash was equipped with an air-brake and its influence on the accident is basically unknown. This work may be considered as a first attempt to establish CFD as a tool to aid in resolving aerodynamic aspects in motor sport accidents and in the present paper, CFD has been used to investigate the aerodynamics and estimate the drag and lift coefficients of the Mercedes-Benz 300 SLR used in the Le Mans race of 1955. The CAD data was obtained by scanning a 1:24 model car and these data were then pre-processed in ANSA and Harpoon, resulting in a volume mesh with 13.5 million cells. Drag and lift coefficients were calculated for a free-stream velocity of 200 kph. Different flow cases were simulated; the Mercedes-Benz 300 SLR on and off the ground, and with and without the air brake in operation. It has been found that the air-brake generates a significant drag increase and a down force on the rear part of the vehicle, as has been documented by the drivers. Furthermore, the Mercedes-Benz 300 SLR is exposed to a lift force in the position on the ground without the airbrake engaged.