approached by California car builders Troutman and Barnes, who were seeking funding for a new front-mid-engined, two-seat road racer. Hall backed the project and named the vehicle Chaparral. He had success with the Chaparral 1, winning the Road America 500 and other races. But almost as soon as it was completed Hall began thinking of a successor vehicle he would build himself. Influence Possibly no designer from the second half of the 20th century has had more enduring influence. Hall pioneered wings, movable aerodynamic devices, side-mounted radiators, semi-automatic transmissions and composite monocoque chassis structures, all of them innovations later adopted by and still present today in every Formula 1 car. He was one of the first to recognize and demonstrate the performance benefits of torsional rigidity. The chassis of his Chaparral 2 — it later became known as 2A to distinguish it from subsequent Chaparrals — was by design about four times stiffer than those of the leading sports cars of the day. Hall also introduced the world's first constant downforce racecar, the 1970 Chaparral 2J, which used a snowmobile engine to power two fans to reduce the air pressure between the bottom of the car and the road regardless of vehicle speed. (Both wings and ground effect tunnels generate downforce that varies with vehicle speed.) At the 1970 Riverside Can-Am the 2J qualified more than two seconds faster than the championship-winning McLaren M8D. The 2J was also the first car equipped with vacuum-protecting “skirts,” another innovation later adopted by Formula 1. Although it was quickly banned, the 2J “vacuum cleaner” concept was copied eight years later by Brabham Formula 1 designer Gordon Murray who figured out a way to circumvent the rules. The resulting Brabham BT46B, won the only race in which it was entered, the 1978 Swedish Grand Prix, proving significantly faster than Colin Chapman's ground effect-tunneled Lotus 79, which secured that year's championship. The development of downforce, from spoilers on his Chaparral 2A to wings movable and otherwise on his Chaparral 2C, 2D, 2E, 2F, 2G and 2H to the suction system on his 2J, was arguably Hall's single greatest contribution to the sport and the one most copied. In 1979, Hall also became the first to bring ground effect tunnels to IndyCar racing with his groundbreaking Chaparral 2K. Today, because of Hall, downforce is part of the design brief for every major form of racing car