Lotus 56 – the turbine car
At Indy the next year, as Clark’s Lotus 38 ate its own engine, Chapman bore witness to the experimental, turbine-powered, four-wheel-drive STP-Paxton Turbocar that lead most of the race. Piloted by Parnelli Jones, it led until just eight miles from home. The chairman of STP and the man behind the Turbocar, Andy Granatelli, proposed a partnership with Lotus, and persuaded Chapman to pursue the turbine route for the next year’s Indy 500.
The resulting design – designated 56 – incorporated the Ferguson all-wheel-drive and a mid-mounted Pratt & Whitney ST6 turbine engine into the iconic wedge-shaped aluminium monocoque designed by Maurice Philippe. Carefully developed in the wind-tunnel, the design was simple but aerodynamically advanced for the time.
Battered by the devastating loss of Jim Clark, Chapman and Lotus were set to field four Lotus 56s for the 1968 Indy 500. Mike Spence, Clark’s Indy replacement, had set impressive times at the Speedway in practice, but tragedy struck again when he crashed and succumbed to his injuries. In the face of great loss, Lotus fielded three 56s in 1968 driven by Graham Hill, Joe Leonard and Art Pollard. There was no doubting the cars speed. Hill and Leonard both set record times in qualifying, grabbing pole and second on the starting grid. In the race, Hill retired on lap 110 after hitting the wall and a fuel delivery problem on the Leonard car saw him retire in the lead with nine laps to go. Pollard’s car failed similarly moments later. For such a cutting-edge machine the Lotus 56 was remarkably fast from the get-go and came agonisingly close to a win on its debut. Unfortunately, both turbine engines and four-wheel-drive systems were subsequently outlawed by the USAC.
Though rendered obsolete in America, the 56 resurfaced in 1970 for testing fitted with large front and rear wings. The four-wheel-drive system was effective, but terrible lag from the turbine meant a driver had to maintain throttle through braking zones just to keep turbine speed necessary for acceptable acceleration. Whilst entered into a few F1 events in 1971, the 56B proved temperamental with little success and was ultimately shelved.
The Lotus 56 remains iconic despite its chequered competition history. It pushed the boundaries of design, engineering and even motorsport regulations to the limit.