Monster in a Box: The Sucker Car/Jim Hall

by Neil M. Denari

Airflow Obsession
After designing and producing variations of five different sport racing cars in the 1960’s, Jim Hall, the mastermind of Chaparral Racing, conceived and designed the most advanced car of its time, the Chaparral 2J. Racing, in contrast to street legal cars, even those of considerable style and speed, is a simple game: cross the finish line first and you win. Like all innovators, Hall was concerned with the ways in which the nuances and logics of the machine, the course, the elements, and the driver all fit together to achieve the highest performance possible within a given set of race parameters. His earlier Chaparral models were, to a certain extent, a serial progression away from the governing conventions of forms and materials that dominated the Can-Am (Canadian-American) and LeMans style endurance circuits of the 1960’s.

Determined to use aerodynamics as the primary factor in design, Hall unleashed less style and more form based on the contours of air movement over, under, and through the envelope of the car. By the time he arrived at the thinking that provided the inspiration for the 2J, his obsession with airflow had shifted from a surface model to a machine model, essentially using the brutality of power within the car as a means to resist the lateral inertial forces acting on the car, especially those occurring during extreme cornering. Thus was invented the most technologically advanced form of Ground Effects: Vacuum Assisted Roadholding and what was the first car to merge fluid and mechanical forms of aerodynamic design.

Vacuum Formed
In looking at circuit racing from a practical point of view, Hall figured that having to slow the car down to traverse tight corners, s curves, and various chicanes, was the main impediment to increasing overall quickness around the track. Maintaining high speeds through the turns, even if it meant giving up a bit of top end speed, would allow a consistent and aggressive line with little braking required. Hall calculated that the time spent in full throttle on straight conditions was considerably less than the areas spent changing gears and braking to deal with the complexities of circuit racing. Therefore, more overall time would be made up if a car could be designed to resist excessive lateral movement through the curves.

On the Chaparral 2E, F, and G, Hall’s advanced airflow management centered around an inverted airfoil wing raised high above the body and turbulent air, so it could run in a stream of clean air. These superstructural devices not only radically changed the performance of the cars; the optical recognition of speed had now shifted from smooth curvatures to assemblies of moving parts. While efficient in their ability to produce tremendous downforce on the rear end of the car, Hall searched for even more control of the forces needed to stabilize and ground the car gravitationally. He had to, because all movable aerodynamic devices had been banned by the FIA, the governing racing body. Instead of pushing the car down from above, Hall inverted the solution by imagining that sucking the car down to the ground from below would increase its ability to maintain a fast line through the turns and succeed in eliminating wasteful milliseconds on braking patterns. The 2J became a machine of force whose form was dictated by the mechanisms of program.

Like a vacuum cleaner hose stuck on a rug, the air under the 2J was sucked out of an area underneath the car which was closed off against the road surface by operable Lexan polycarbonate panels. In this, the FRP body acted like a plenum chamber to contain the artificially generated low pressure area. Instead of running this vacuum from the main engine of the car, Hall added a dedicated engine to run the fans needed to remove the air from the plenum. A Rockwell-JLO snowmobile engine (274cc / 55bhp) is mounted at the rear of the car, effectively making a cantilevered beam out of the two combined engines. This beam, in combination with the lightest weight monocoque chassis ever built, balanced the car and was strong enough to resist the extra force on the frame generated by the vacuumed air.

Geometry as Indicator
In combination with a front end of conventional downforce surface design, the boxlike form of the rear end of the car produced one of the most unlikely mergers in any field of industrial design, then or now. Looking more like a chopped refrigerator than a visually fluid and logically deformed body, indeed, the 2J moved like a fox, despite its unorthodox hedgehog form. That the world’s most advanced car would appear as an object seeming to be governed by a Cartesian system usually associated with the larger and less supple medium of architecture is surely where the fascination with this vehicle comes from. Its primitive exterior and mechanically complex interior suggests a paradoxical relationship equal to the relationships between basic architectural form and the fluctual, complex pathways of the human body moving through space. As architecture is disciplined now more by ideology than by industry, the 2J’s morphed box was a moment in high-tech determinism, a monster-in-abox solution to a simple problem. If the 2J is ugly in racing terms, then as a building it would suddenly become an exquisite object whose linear and transitional morphology from contoured profiles to blunt right angles would no doubt index programmatic shifts or on a formal level, it would describe an ideological regime that is not content to define a position through one end or the other. This car was new, not schizophrenic, because if it were merely the latter, it would not have been banned from racing in November 1970, after just four races.






















Neil M. Denari Architects