Chaparral or Jim Hall that’s a big name in North American road and oval racing. Known for his inovative way of work, the materials involved and of course, his look at the aerodynamics. Yes, back in the late sixties, early seventies, Chaparral was known as the aero master in CanAm racing even if that lead to one of his car being banned from the series and eventually to his first retirement but that’s another story..!
The Chaparral 2K was an Indy racer designed and using some principles that Jim Hall had actually tried back in 1970 with his 2J CanAm design, ground effect. Jim even if retired was still arround watching and looking at the cars and design. Interest came back when the Lotus 78 Formula One car came out using the same principle but in a much different way. While Jim designed the 2J CanAm car as a “suction” car using two anxiliary motors to suck the air from the underbody of the car, the Lotus 78 was designed using an all new design. The underside of the car was shaped like the top surface of an aircraft wing. This is without doubt what led him to that new car being built, with this new way, no need of anxiliary motors and that solved the major problem of the motors failing during the races on the 2J which lead in time to so many retirements or DNFs.
The design of the chassis was the work of John Barnard, the man behind theWorld Championship winning McLaren M23 and who will later start an all new era in chassis design withe famous McLaren MP4, the first ever carbon chassis made for the category. But anyway, the chassis was a conventional aluminium monocoque featuring front inboard suspension with top rockers. All that was matted to a Cosworth DFX V8 producing in excess of 700HP and a Weissmann 4-Speed gearbox. The interesting bit are the tunnels which ran all the way from the front wheels to the back of the car and it’s integrated rear wing. Another unusual feature of the car was the back end, suspension and packaging. The car featured a sort of sub-chassis on which the wing was mounted as well as the suspension which in some way were mounted outboard as you can see on the picture below. This allowed for better tunnels and air-flow as nothing was in the way and that airflow was maximized with the exit of the tunnels being right in the low pressure zone of the wing in a way that it reduced the drag of the car.
The car was successfull from the start in 1979, Al Unser Sr. qualified the car, the first ever ground effect car to race at the Indy 500 on the front row that same year. Grabbing the lead at the start, the car showed a phenomenal pace and it looked like a debut victory for the car until the transmission broke at mid-distance. The following races were great, the car showing that the design was effective and fast. Victory came in the penultimate round of the season at Phoenix. 1980 saw the car winning the Indy 500 with Johnny Rutherford at the wheel, having qualified on pole with an average speed of 192,257 mph (309,408 km/h). A total of 5 wins and 8 podiums was more than enough that year to take the CART championship as well. In 1981, the opposition had worked out the concept as well and the car proved less dominant, in 1982, the car did participate in the first races before being replaced by a March chassis which lead to the second retirement of Jim Hall and Chaparral.
As a one car team, Chaparral proved his thinking and design once again, 7 wins in three season including the Indy 500 and only two finish out of the top five. A great result and a testimony to the man that in a way faced mixed fortunes with his early ground effect car but who finally came back and beat the opposition and introduced a new trend in the category.