Chaparral Cars

Chaparral Cars was a United States automobile racing team which built race cars from 1963 through 1970. Chaparral cars was founded in 1962 by Hap Sharp and Jim Hall, a Texas oil magnate with an impressive combination of skills in engineering and race car driving. The combination of the last names of the two founders resembled the Spanish word "Chaparral" (Roadrunner) so it was chosen. Despite winning the Indianapolis 500 in 1980, they left motor racing in 1982. Chaparral cars also featured in the SCCA/CASC Can-Am series and Endurance racing.

Chaparral was a leader in effective designing of air dams and spoilers. Their high point being the 1966 2E can-am car. The 2J is the first "ground-effects" car. The unique use of a semi-automatic transmission beginning with the Chaparral 2 is a major reason for their early success. Tires weren't good enough yet to be able to use all the power the 327 Chevy engine could make in 1964, so the torque converter allowed for better traction.

The development of the Chaparral chronicles the key changes in race cars in the 1960s and 1970s in both aerodynamics and tires. Jim Hall's training as an engineer taught him to approach problems in a methodical manner and his access to the engineering team at Chevrolet as well as at Firestone changed aerodynamics and race car handling from an art to empirical science. The embryonic data acquisition systems created by the GM research and development group aided these efforts. An interview with Jim Hall by Paul Haney illustrates many of these developments. Canadian Automobile Sport Clubs

1
1957. Jim Hall raced the front engined Chaparral 1 through 1962. Like the Scarab they were built in California by Troutman and Barnes. They were the only Chaparrals to be raced by someone other than Chaparral cars.

2
The first Chaparral 2-Series was designed and built to compete in the United States Road Racing Championship and other sports car races of the time, particularly the West Coast pro Series that were held each fall.

First raced in late 1963, it developed into the dominant car in the series in 1964 and 1965. Designed for the 200 mile races of the sports car series, it was a winner. Not built for endurance racing, in 1965 it shocked the sportscar world by winning the 12 Hours of Sebring in a pouring rain storm, on one of the roughest tracks in North America.

The Chaparral 2 featured the innovative use of fiberglass as a chassis material. The Chaparral 2C had a conventional aluminum chassis.

It is very difficult to identify all iterations of the car as new ideas were being tested continually.


 * The 2A is the car as originally raced, featuring a very conventional sharp edge to cut through the air. It also featured a square tail with a concave tail reminiscent of the theories of Dr. Wunibald Kamm. Almost immediately an issue with the front end being very light at speed with a consequent impact on steering accuracy and driver confidence. The first aerodynamic appendages began to appear on the 2A.


 * As the car evolved, it grew and changed shape. Most call these the 2B, as raced through the end of 1965.


 * The 2C is the next car with the innovative in-car adjustable rear wing. The integrated Spoiler/wing, designed to lie flat on the straight(low drag) and tipped up under braking through the corners. This was a direct benefit of the clutchless semi-automatic transmission which kept the left foot free to operate the wing mechanism. The 2C was based on a Chevrolet designed aluminum chassis and was a smaller car in every dimension than the 2B.  Without the natural non-resonant damping of the fiberglass chassis,  Jim Hall nicknamed it the EBJ — "Eye Ball Jiggler".

Alongside the development of aerodynamics was Hall's development of race tires. Jim Hall owned Rattlesnake Raceway adjacent to his race shop; the proximity allowed him to participate in much of Firestone's race tire development.

A two-article series in Car and Driver magazine featured Jim Hall's design theories. The article turns speculation about vehicle handling into applied physics. It was the precursor to the elaborate data collection and management of current racing teams.

The 2D was the first closed cockpit variant of the 2 series, designed for endurance racing in 1966. It won at 1000 km Nürburgring in 1966 with Phil Hill and Joakim Bonnier driving. It also competed in the 1966 24 Hours of Le Mans, withdrawing after 111 laps. The Chaparral 2D's 327 Chevrolet engine had 420 horsepower, and weighed only 924 kg.

The 2E was based on the Chevrolet designed aluminum 2C chassis and presented Jim Hall's most advanced aerodynamic theories to the racing world in the 1966. The 2E established the paradigm for virtually all racing cars built since. It was startling in appearance, with its radiators moved from the traditional location in the nose to two ducted pods on either side of the cockpit and a large wing mounted several feet above the rear of the car on struts. The wing was the opposite of an aircraft wing in that it generated down-force instead of lift and was attached directly to the rear hubs, loading the tires, for extra adhesion while cornering. A ducted nose channeled air from the front of the car up, creating extra down-force as well. By depressing a floor pedal that was in the position of a clutch pedal in other cars. Hall was able to feather, or flatten out, the negative angle of the wing when down-force was not needed, such as on a straight section of the track, to reduce drag and increase top speed. In addition, an interconnected air dam closed off the nose ducting for streamlining as well. When the pedal was released, the front ducting and wing returned to their full down-force position. It was a brilliant design. Until they were banned, many sports racing cars, as well as Formula One cars, had wings on tall struts. Many were not as well executed as Hall's. The resulting accidents from their failures caused movable wings mounted on the suspension (as movable aerodynamic devices) to be outlawed.

The 2E scored only one win at the 1966 Laguna Seca Can-Am with Phil Hill driving. Hall stuck to an aluminum 5.3 liter Chevrolet engine in his lightweight racer, while the other teams were using 6 to 7 liter iron engines, trading weight for power.

The 2E was a crowd favorite and remains Jim Hall's favorite car.

In the 2F Hall applied the aerodynamic advances of the aluminum 2E to the older fiberglass chassis closed-cockpit 2D for the 1967 racing season. A movable wing, on struts, loaded the rear suspension while an air dam kept the front end planted. The radiators were moved to positions next to the cockpit. An aluminum 7 liter rat motor replaced the 5.3 liter engine of the 2D. While always extremely fast, the extra power of the larger engine was too much for the automatic transmission to handle and it broke with regularity. When a solution was found to the transmission problems, the 2F scored its only win on 30 July 1967 in the BOAC 500 at Brands Hatch with Phil Hill and Mike Spence driving. After this race, the FIA changed its rules, outlawing not only the 2F as well as the Ford GT40 Mk.IV (winner at Le Mans that year) and the Ferrari 330 P3/4 and 365 P4 (winner at Daytona, 2nd at Le Mans).

As with the 2D, the 2F raced wearing a Texas license plate.

The 1967 2G was a development of the 2E. It featured wider tires, and a 427 aluminum Chevrolet engine. While on par with his competitors in terms of power, the lightweight 2C chassis was stretched to the limit and it was only Hall's driving skill that kept the car competitive. For the 1968 Can-Am series, still larger tires were added.

Jim Hall's racing career was effectively ended in a severe crash at the Stardust Grand Prix Can-Am race. His car flipped after rear ending the slow moving McLaren of Lothar Motschenbacher, although he did drive in the 1970 Trans-Am Series while fielding a team of Camaro Trans-Am cars.

Never one to be complacent, Jim Hall noted that the increasing down-force also created enormous drag. Seeking a competitive edge, the 2H was built in 1969 as the replacement for the 2G to minimize drag, rather than maximize down-force. However, the anticipated gains in speed were more than offset by the reduced cornering speeds and the car was consistently slower than anticipated.

A failure, it eventually was fitted with a huge wing.

2J
The most unusual Chaparral is the 2J. On the chassis' sides bottom edges are articulated plastic skirts that seal against the ground (a technology that would later appear in Formula One). At the rear of the 2J are housed two 17-inch, JLO (pronounced "EE-lo") fans driven by a single 45 hp two stroke twin snowmobile engine. The car had a "skirt" made of Lexan extending to the ground on both sides, laterally on the back of the car, and laterally from just aft of the front wheels. It was integrated with the suspension system so the bottom of the skirt would maintain a distance of one inch from the ground regardless of G forces or anomalies in the road surface, thereby providing a zone within which the JLO fans could create a partial vacuum which would provide a downforce on the order of 1.25-1.50 G of the car fully loaded (fuel, oil, coolant). This downforce, materially greater than the weight of the car, had one journalist remark--literally quite accurate--that the 2J, which weighed less than ton, with its JLO motors running and generating their downforce of 1+ G could have been unveiled to the public on the ceiling. This gave the car tremendous gripping power and enabled greater maneuverability at all speeds. Since it created the same levels of low pressure under the car at all speeds, down-force did not decrease at lower speeds. With other aerodynamic devices, down-force decreases as the car slows down or achieves too much of a slip angle, both of which were not problems for the "sucker car".

The 2J competed in the Can-Am series and qualified at least 2 seconds quicker than the next fastest car, but was not a success, because it was plagued with mechanical problems. It ran for only one racing season, in 1970, after which it was outlawed by the Sports Car Club of America (SCCA). Although originally approved by the SCCA, they succumbed to pressure from other teams, McLaren in particular, who argued that the fans constituted "movable aerodynamic devices", outlawed by the international sanctioning body, the FIA, a rule first applied against the 2E's adjustable wing. There were also complaints from other drivers saying that whenever they drove behind it the fans would throw stones at their cars. McLaren argued that if the 2J were not outlawed, it would likely kill the Can-Am series by totally dominating it — ironically, something McLaren had been doing since 1967. A similar suction fan was used in Formula 1 eight years later for the 1978 Swedish Grand Prix, by the Brabham BT46B, but was banned soon after. It was ruled that the fans were considered movable aerodynamic devices and thus both 2J and the BT46B were outlawed under the same rule that outlawed movable wings years earlier.

2K
The 2K was a Formula One-inspired ground effect Indy car designed by Briton John Barnard. Debuting in 1979 with driver Al Unser Sr., it went on to win six races in 27 starts over three seasons. Its greatest success came in 1980, when Johnny Rutherford drove it to victory in both the Indy 500 and PPG Indy Car World Series championship.

Museum
In 2005, a wing of the Permian Basin Petroleum Museum in Midland, Texas was dedicated to the permanent display of the remaining Chaparral cars and the history of their development by Midland native Jim Hall.

Tributes

 * The 2005 Monterey Historic Automobile Races honored Chaparrals as the featured marque. Hall's Chaparral 2A had won the Monterey Sports Car Championships at Laguna Seca Raceway in 1964.
 * In the 2009 Monterey Sports Car Championships, Gil de Ferran painted his Acura ARX-02a to resemble a Chaparral in tribute to Jim Hall, for whose team de Ferran drove in his first two seasons in Champ Car, and also to commemorate de Ferran's final professional race. An exhibition race featuring the Acura and three Chaparrals was held that Friday, and Hall performed a demonstration lap shortly before the race.