Many of Chapman's successes came from innovation. The Lotus 25 was the first monocoque chassis in F1, the 49 was the first car of note to use the engine as a stressed member, the Lotus 56 Indycar was powered by a gas turbine engine and was fitted with four-wheel drive, the Lotus 63 was the first mid-engined F1 car to race with four-wheel drive, and the 72 broke new ground in aerodynamics. Chapman was also an innovator as a team boss. For , the FIA decided to permit sponsorship after the withdrawal of support from automotive-related firms, such as BP, Shell and Firestone. In April, Team Lotus was the first works team to paint their cars in the livery of their sponsors, with Clark's Type 48 F2 appearing at Hockenheim in the red, gold and white colors of Imperial Tobacco's Gold Leaf brand. The first Formula One car in this livery was Graham Hill's Lotus 49B entered at the 1968 Spanish Grand Prix in Jarama.