Model history: After his revolutionary Chaparral 2J was banned during the 1970 Can-Am season, Jim Hall temporarily turned his back on racing. In the decade before his departure, Hall had been a prominent figure in American sports car racing as driver, constructor and team owner. He took up that latter role again in 1974 when he fielded a F5000 Lola for Brian Redman. Hall's team won the title three years running and subsequent efforts in the resurrected Can-Am championship and Indy racing were equally successful. In 1978 Al Unser drove a Chaparral entered Lola to victory in the Indy 500 at Hall's first attempt. When Unser returned to Indy a year later he was behind the wheel of the all-new, highly advanced Chaparral 2K.
What had made the 2J of 1970 so special and at the same time controversial was its ingenious aero package. Instead of using wings to push the car to the track, it featured two fans that sucked the air from underneath the car. The resulting low pressure area under the car resulted in a similar downforce levels without the drag created by wings. The sport's governing body determined that the fans were moveable aerodynamic devices and declared the 2J illegal. A few years later Lotus built a Formula 1 car that used the same principles but without using a fan. Instead the underside of the Lotus 78 was shaped like a the top surface of an aircraft wing. As on the 2J, skirts mounted in the 'side-pods' sealed off the low pressure area. As an aerodynamic pioneer, Hall took a great interest in the Lotus 'ground effect' car. It no doubt inspired him to once again build a car of his own design.
For the actual design of the 2K, Hall called upon the services of British engineer John Barnard. His designs for Lola had already contributed greatly to the success of Chaparral Racing of the previous years. Barnard created a conventional bonded and riveted aluminium monocoque chassis. At the front, lower wishbones and top rockers were fitted while the rear-end sported double wishbones. The new Chaparral was powered by a Cosworth-built 2.65 litre V8 engine. Equipped with a single turbocharger, it produced in excess of 700 bhp. This was fed to the rear wheels through a Weismann four-speed gearbox. Following Chapman's principles, full length side-pods were fitted, lined by moveable skirts. The narrow engine and gearbox allowed the ground effect tunnels to run all the way to the integrally mounted rear wing.
Liveried in the simple but effective Pennzoil colours, the first Chaparral 2K was ready in time for Unser's defense of the Indy title. Indy racing's first proper ground effect car instantly made its mark as Unser qualified the car on the first row. He immediately grabbed the lead in the race and looked set to take a startling debut victory for the new Chaparral until a transmission seal in the gearbox expired on lap 104. Unser was eventually classified 22nd. At the 2K's next outing Unser managed a second place finish. During the remainder of the season, Unser regularly showed how quick the Chaparral was but he had to wait for the elusive victory until the final race of the season at the Phoenix International Raceway. He had placed the 'Yellow Submarine' second on the grid and led 138 of the 150 laps of the race. Unser crossed the line ahead of his brother Bobby and his Penske team-mate Rick Mears.
For the 1980 season, Hall hired fellow Texan and two-time Indy 500 winner Johnny Rutherford to drive the Chaparral 2K. The team picked up where it had left off in 1979 by winning the opening round at Ontario. Rutherford continued this great run at Indy, scoring his third and the team's second win in the classic event. 'Lonestar J.R.' went on to win a further three races in the Chaparral that year. In twelve races he finished on the podium eight times and took a total of five wins, which was more than enough to beat Penske's Bob Unser in the CART championship. The 2K was used again in 1981 but by now many of the other manufacturers had caught up with ground effect cars of their own. Rutherford only managed to win the opening race and finished fifth in the standings. After continued poor results in the first races of the 1982, Hall decided to replace the ageing Chaparral 2K with a fresh March chassis for Rutherford to complete the season with. At the end of the year, Hall once again retired from racing.
In his final exploit as a constructor, Hall had managed to successfully break conventions again. Like many of his revolutionary designs, the Chaparral 2K worked as well on the track as it did on paper. Seven victories in little over three seasons of racing is a very impressive feat, especially considering Chaparral Cars never fielded more than one car per race. After a season packed with trial and error, the 2K was as reliable as it was quick in 1980. Rutherford only failed to place the car inside the top five on two occasions. The victory in the Indy 500 was a more than fitting crown for Jim Hall's career in racing. It was also wholly appropriate that Hall could finally achieve some real success with the 'ground effect' principles he had helped develop in the first place. As an entrant, Hall would return to Indy racing once more in the early 1990s with considerable success but no more Chaparrals were produced.
It is believed that three Chaparral 2Ks were built of which two have survived. One is still owned by Jim Hall, the second is on permanent display at the Indy Hall of Fame and the third is presumed to have been destroyed by Rutherford during a massive crash at Phoenix in 1980.
Chassis 2K-01 was the first of three Chaparral USAC/CART racers constructed. From the Indy 500, it was raced by Al Unser during the 1979 season. Unser finally scored a victory in the final round of the year at Phoenix. During 1980, it was raced by Johnny Rutherford in his run to the championship. It was also one of the two cars used by Rutherford during the build-up to the Indy 500. Today it is owned by the Indianapolis Hall of Fame Museum and is currently in full running order. It is seen here during the 2011 Goodwood Festival of Speed where the Indy 500 centennial was celebrated. Among its drivers were Johnny Rutherford and also the late Dan Wheldon.
The second Chaparral 2K built, chassis 2K-02 was pressed into service late in the 1979 season. Al Unser drove it at Michigan and on the Ontario Speedway. In the following season, new Chaparral driver Johnny Rutherford used the car, scoring his first victory for the team on the Ontario Speedway. Chassis 2K-02 was also used by Rutherford on his way to his third Indy 500 victory. Still owned by Jim Hall, this Chaparral 2K is today on display in Midland, Texas' Petroleum Museum. It is seen here during the 2005 Monterey Historics where Jim Hall was honoured.