The design study of a racing car is not limited to its bodywork. Underneath, the flow of air can create a ground effect capable of sucking the air out from below the car! Underestimated for a time, this unique solution is now regulated.

January 28, 1938, between Frankfurt and Darmstadt – The season started far from the circuits, on a portion of highway, with a duel between two record attempting constructors. To beat Mercedes, Auto Union (Audi) equipped their Type C with a V16 engine producing close to 600 horsepower. Following aerodynamic tests in a windtunnel, engineers added skirts which generated a ground effect allowing the driver to keep control of the car when going at speeds of 450 kph.  Unfortunately, these additions would not be enough, and a gust of wind swept the Silver Arrows off the road, ejecting driver Bernd Rosemeyer, who died on the spot.

After this painful experience, the Auto Union would move on, each maker prefering to concentrate their efforts on the motor and chassis. It wasn't until the early 1960s that Charles Deutsch would lead detailed studies on the complementary nature of the bodywork, suspensions, chassis and tyres, and also ground effects. With the CD model entered in the 1964 Le Mans 24 Hours, Deutsch opened the door for modern aerodynamics, simple bodywork profiles being replaced with designs optimised in aerodynamic and dynamic handling.

Very quickly, mastering the flow of air around a car became the key to success, and wings are born. After racing with the most daringly large rear wing ever seen at Le Mans in 1967 (Chaparral 2F), Jim Hall became interested with what was under the car. And true to style, he didn't do things lightly! For the 1970 season, he invented the first active ground effects car in the world: the flow of air under the car is sucked up by two fans in the rear, generating impressive levels of downforce. Although the endurance racing world would quickly ban the use of auxillary engines, the concept would return eight years later in F1 on the Brabham BT46 designed by Gordon Murray.

Today, ground effects on LMP cars is limited to two channels measuring 1750mm in length.

Julien HERGAULT / ACO - Translated by Rainier Ehrhardt / ACO