Chaparral’s Jim Hall was a visionary in the field of motorsport aerodynamics. His radical way of thinking produced designs decades ahead of their time. The pioneering of downforce inducing spoilers in 1966 earned him a great amount of respect and paved the way for widespread implementation throughout the industry.
By 1970 however, Hall was faced with a problem. Due to countless accidents caused by broken wing struts in Formula 1, the use of high mounted wings and movable aerodynamics was banned across the entire motorsport world. Because most of his cars had used such designs, Hall had to come up with something completely different. After years of exploring the pros and cons of high downforce as well as low drag designs Hall was ready to implement something entirely different into his new Can Am car.
Even though movable aerodynamics and high mounted wings were banned, Can Am was still the sole category with the most liberal rule book on the planet. Hall used this fact fully to his advantage for his newest design. He started out with a traditional aluminium monocoque chassis, and fitted a fuel-injected 7.6L (465 ci) aluminium Chevrolet V8 developing 760 horsepower and 881 nm (650 ft lbs) in the back. In traditional Chaparral style the engine was mated to an in-house developed 3-speed automatic gearbox.
His next step was a bit more unusual. The giant V8 was joined by a 400cc Rockwell two-cylinder two stroke snowmobile engine. This tiny power plant was connected to two giant 17-inch fans taken from a military tank engine. The fans would suck all of the air out from under the car to create a partial vacuum. Hall called this principle “ground-effect”.
This was made possible by fitting lexan skirts around the perimeter of the car, starting just behind the front wheels. A lateral piece of lexan between the front wheels and behind the rear wheels closed off the square, forming a giant box under the car. The skirts were tuned in relation to the suspension to prevent them from actually hitting the road surface at all times.
As soon as the car was started up, the low pressure area created by the massive fans would violently “suck” it down into the road. This effect pushed its tires hard into the tarmac, which made them grip much harder. Extremely wide tires were fitted to make the most of this phenomenon.
Traditionally, one of the drawbacks of a car producing high downforce from big spoilers was a massive amount of aerodynamic drag. This would slow down the cars on the straights. Another flaw was the fact that the wings could not function at low speeds, as the air would not be flowing over the car fast enough to produce sufficient downforce. Cars that were set up to rely on downforce to assist in handling would prove to be very tricky when driven through slow corners.
The 2J suffered from none of these problems. It already produced 1.25-1.50 G of downforce when parked on the grid, courtesy of its diligent snowmobile engine. This meant the car would enjoy incredible amounts of grip and traction at any and all speeds. A further advantage was the fact the the car had no need for big wings, which allowed for a simple and effective low drag body design.
Feeling pretty confident in his concept, Jim Hall rushed to bring the car into competition. He feared other teams would get wind of his ideas and try to copy them. In the 1970 Can Am season, the 2J would have to take on the giants of the now well-developed sport. Hard hitters like the Porsche 917PA spyder, Ferrari 512 S Spyder, various Lola’s and McLaren’s all-conquering M8D were in its way.
1969 Formula 1 World Champion Jackie Stewart (GB) was hired to drive the revolutionary car. This was not a small feat for the small Chaparral firm, as Stewart was in high demand and commanded an equally high price. In spite of this, his interest was sparked by Hall’s offer and he agreed to make a deal. More than anything, the fresh World Champion wanted to know what the heck this seemingly magical car actually was.
Famously, Jackie Stewart was one of the first high-profile race drivers to worry deeply about safety. When first presented with the car, he walked around inspecting the seat belts, shoulder harness and the steering wheel. Stewart had some demands here and there, but was delighted with another clever Chaparral innovation. Jim Hall and his engineers had developed the quick-release steering wheel, giving Stewart the opportunity to leave the car in a hurry if he needed to.
The 2J missed the first two rounds of the championship, but was ready for the third at Watkins Glen. Despite its rushed introduction, it still managed an impressive 3rd placing in its first ever qualifying session. This put the experimental machine behind the mighty McLarens of Denny Hulme (NZ) and Dan Gurney (USA). Sadly the race ended in a disappointing DNF due to an unfortunate brake failure. Nevertheless the almost limitless potential of the design had been proven.
Reworking of the car’s teething problems took another three rounds. It reappeared at Road Atlanta for seventh round with extremely experienced sportscar ace “Quick” Vic Elford behind the wheel, since Jackie Stewart had other commitments. Elford put the car firmly on pole by 1.2 seconds, beating the presumed invincible McLarens. On race day inconsistent performance from the snowmobile engine caused Vic to drop down into 6th position, recording the car’s first ever finish. The 2J missed the next round at Donnybrooke for further redesigns and would fail to start at Laguna Seca due to persistent reliability problems.
At Riverside Vic Elford blasted the field by putting the car on pole by an amazing margin of a full 2 seconds.This left the rest of the field in a bad mood. Elford would lead most of the race unthreatened, until the snowmobile engine decided to call it quits in the middle of a high speed turn. The car suddenly lost all artificial downforce and snapped into a violent spin. “Quick” Vic lived up to his name and kept the car out of the wall with lightning fast reflexes. Without the added downforce the car was hopelessly slow and overweight, so the team decided to pull it out of the race.
Even though the car failed to finish on numerous occasions, its qualifying prowess had greatly worried the competing teams. They knew once the car’s reliability problems would be sorted, it would become virtually unbeatable. Without wasting time they filed a mass of complaints immediately after the Riverside event.
McLaren, in an ultimate display of lack of self-awareness, said the 2J’s possible dominance would surely kill the Can Am series. This was ironically something they themselves had been doing since 1967. Several drivers from other teams complained that the huge fans would throw stones at them when they followed behind. In the end the incessant whining turned out to be successful. The car’s fans were ruled to be “movable aerodynamic devices”, which meant the 2J was banned from competing in Can Am any further.
The Chaparral 2J was a machine decades ahead of it opposition, in true Chaparral style. It’s ambitious and complex design yielded amazing speed, but came at the cost of reliability. Technical failures would see it drop out on more than one occasion, but politics would be it’s true downfall. In the end tidal wave of complaints from its rivals washed away its chances of ever winning a race.
After years of defending his outlandish designs, Jim Hall tired of fighting his rivals and the racing authorities. He closed down his shop for over a decade, later returning to racing with the successful 2K Indycar. Hall had however drawn up a new Can Am car for 1971 using venturi-tunnels in the underbody of the car to create ground-effect without using an extra engine. This brilliant principle would later show up in Formula 1 in 1977 with the 78 “wing car”, and in 1978 Brabham would fit a similar fan system on the infamous BT46B.