Team Lotus developed the Lotus 56 as an evolution of the concept pioneered by the STP-Paxton Turbocar, nicknamed "Silent Sam," which had nearly won the 1967 Indianapolis 500. Rather than continuing with the cigar-shaped bodywork of its predecessor, designer Maurice Philippe introduced a radical wedge-shaped aerodynamic body — a form that would eventually define open-wheel car aesthetics for a decade. The car retained four-wheel drive and used a modified version of the ST6 gas turbine, though revised USAC regulations had significantly reduced the permitted air intake size, limiting power compared to the previous year's turbine entry. To compensate, the Lotus 56 relied on advanced suspension design, reduced weight, and its pioneering aerodynamics.
The development period was marked by profound tragedy. Team leader Jim Clark, who had briefly tested the car, was killed in a Formula 2 race in Germany before the 1968 season began. His replacement, former teammate Mike Spence, was then killed at Indianapolis itself during testing. The team pressed on with drivers Graham Hill, Joe Leonard, and Art Pollard.
At the 1968 Indianapolis 500, Joe Leonard claimed pole position, underlining the car's competitiveness. Unlike the previous year, when the STP-Paxton turbine had comprehensively outpaced the field, the Lotus 56 faced more even competition — a testament to the tighter regulations and the improved aerodynamic efficiency of conventional rivals. Hill retired after losing a wheel, and Pollard suffered a fuel pump drive shaft failure. Leonard led the race in the closing laps, only for his fuel pump shaft to fail just eight laps from the finish. For the second consecutive year, an STP turbine entry had led at Indianapolis and failed to convert.
USAC responded by imposing additional restrictions on turbine-powered cars, effectively removing them from competition. Shortly afterwards, four-wheel drive and turbine engines were banned from Indianapolis entirely.
In 1969, Art Pollard returned to Indianapolis with an Offenhauser-powered variant of the Lotus 56 chassis. He qualified on the fourth row but retired early with mechanical failure after just six laps.
Colin Chapman had conceived the Lotus 56 as a dual-purpose design capable of competing at both Indianapolis and in Formula 1. The Formula 1 derivative, designated the Lotus 56B, featured front and rear wings and additional fuel tanks. Emerson Fittipaldi first drove it in the non-championship 1971 Race of Champions at Brands Hatch, where the car was dramatically the fastest in wet practice before the race dried out, leaving it lost in the midfield.
At the International Trophy at Silverstone, the 56B lasted only three laps of the opening heat before suspension failure ended Fittipaldi's race. Dave Walker then drove the car at the Dutch Grand Prix, charging from 22nd to 10th in just five laps of a very wet circuit before sliding off the road. Fittipaldi used the car once more at the 1971 Italian Grand Prix, bringing it home in eighth place — the only championship points finish the 56B would record.
The Lotus 56 never won a race, yet its influence on motorsport was profound. Alongside Jim Hall's Chaparral programme, the Lotus 56 demonstrated the potential of aerodynamic efficiency in racing car design. The distinctive wedge shape pioneered by Maurice Philippe was directly incorporated into the Lotus 72, which went on to win three Formula 1 World Championships. The car's influence extended even to popular culture: Mattel produced a model of the "Lotus Turbine" as one of its mass-produced Hot Wheels die-cast cars. The Lotus 56 stands as one of motorsport's great near-misses — a technically advanced machine whose time simply ran out before the regulations could.