Hill had no trouble getting to grips with left-foot braking. During his first race in the 2D, at Daytona, he and co-driver Jo Bonnier qualified second and led before being slowed by a variety of teething problems and finally sunk by an upright failure. There were two Chaparrals the next month at Sebring, but both of them broke early. Three starts, three DNFs. What were the chances of a lone 2D surviving 1000 kilometres at the Nürburgring?

Pretty good, as it turned out. Now sporting a distinctive snorkel over the cockpit to ram cold air into the engine, the Chaparral was leading when rain started falling. An agonisingly long pitstop to change tyres squandered most of a 4min cushion. And the worst was yet to come. “When I turned on the windshield wipers,” Hill says, “they immediately slipped off the attachment and started wiping the damn hood instead of the windshield.”

Then the rain stopped, and things got really bad. Mud from the track slopped onto the windshield, blinding Hill. “I knew I had to do something,” he says. “But I couldn’t risk shutting off the engine because the batteries were so small that I was afraid I wouldn’t be able to get it restarted. And I could not stop the car because crunching it into gear when the engine was running was a definite no-no.”

So just after the Foxhole, on the slowest part of the circuit, Hill downshifted into first gear, slowed to a crawl, unlatched the gullwing door and levered himself out of the seat to reach outside the car and wipe off a small patch of windshield. Then he went on his merry way — but not before he was spotted by a camera, leading to a TV report that the Chaparral had broken and Hill was climbing out of the car.

“Someone wrote in a story recently that when I stopped in the pits at the end of that lap, the crew was packing up to leave,” Hill says. “That’s not true. I didn’t stop in the pits. I had no reason to. But they were packing up when I tore past.”

The Chaparral went on to score its first win on foreign soil. But Le Mans was a disaster, so the 2D was shelved and work began on its successor.

Like the 2D, the 2F was built around the tub of the original Chaparral 2. Yet, with its hip-hugging radiators and slabsided shape, it looked like something from a different century. The most obvious — and arresting — addition was the giant wing, which hung over the rear deck like a levitating coffee table. Additional downforce was generated by cleverly routing air through the nose.

Oh, and there was one other big change — literally. The small-block was replaced with an aluminium version of the 7-litre big-block Chevy V8 then being raced in NASCAR. Even without exotic tweaks, the engine produced 525bhp. It proved to be more than the transaxle could handle. “We kept losing seals in the gearbox,” Hill recalls. “I still don’t understand why GM couldn’t come up with a quick fix for it.”

The 1967 season was a study in epic frustration. During its first seven races, the 2F recorded 10 consecutive DNFs (there were two-car entries at three races). The team was snake-bitten from the start. At Daytona, a Chaparral was leading the works Fords and Ferraris when Hill made a rare mistake.

“Mike Spence came in and said everything was fine,” Hill says. “So I went out, and I wasn’t even going very fast when the car started to slide on the marbles that had built up where the road course rejoins the banking. I didn’t even try to shut it off. I figured there was no way I could slide all the way into the wall. But I did. I have never felt as bad as I did after that. Jim wasn’t too happy either.”

And that was a high point for much of the season. Consider this litany of woe. Sebring: fastest lap and a gearbox failure. Monza: pole and a driveshaft failure. Spa: fastest lap and a gearbox failure. Nürburgring: pole, fastest lap and a gearbox failure. Le Mans: yet another gearbox failure. Oh, and in between all these breakdowns, a flat tyre knocked Hill and Hap Sharp out of the Targa Florio.

But everything finally came right at Brands Hatch at the end of July. Despite being slowed by driveshaft problems, Spence qualified on the front row next to a Lola T70. Then he and Hill ran away from the factory Ferraris. Hill never raced professionally again. Thanks to a new 3-litre formula for 1968, neither did the 2F. But it showed the way for the next generation of prototypes.

“It was amazing at the Nürburgring,” Hill says. “Instead of flying like a ski jump, it would come right back down to the ground.

“The car was an overt, ambitious and successful attempt to deal with new principles such as aerodynamic performance. Without question, it was a real milestone.”