Kopek on Shelby's trashing of Pete Brock

[Steve Cassani]

Howard criticized the car's aerodynamics, specifically Brock's application of some of Kamm's theories regarding air flow over a moving surface as opposed to a static body with air flowing over it. Recall that the latter is tested in a wind tunnel; the former is verified - using tufts of yarn - after the design implementing the theories has been built and is capable of moving at the desired speed. Howard's work in aviation gave him experience in both but most of his work was with wind tunnels - moving air, static model.

Brock's application of Kamm's work was modified to solve problems not directly attibutable to the theories Brock used:

(1) The openings on either side of the tail were closed - Kamm expected the moving car to create lower air pressure in the cut-off space directly behind it. This was true at a distance of several inches to perhaps a foot behind the car, depending upon vehicle velocity. It was not true in the boundary layer against the surface of the car. Here the air pressure was disturbed beyond what anyone could predict at the time. Brock planned for the lower air pressure trailing the car to draw hot air from the rear brakes. The turbulance around the openings resulted in air being drawn into the car, increasing air pressure in the wheel wells. No mistake: the tufts showed what was happening and the theory was not constructed to predict air flow within an inch or so of the surface of the car.

(2) The roof and windshield were not constructed exactly to Brock's dimensions. Whether the differece was contributory is a matter of conjecture; the tufts showed the flowing air to split up and down as it passed along the sides of the car, missing the air vents in the B-pillars. The solution: clear plastic slabs were added on each side of the A-pillar, creating lower air pressure in their wake and forcing the air back, following the the side windows and into the vents.

These are not the sorts of problems Ken Miles knew how to solve and 15,000 miles of testing are not needed to identify these problems and craft solutions. The changes have Pete Brock's knowledge written all over them, along with Phil Remington's uncanny ability to 'see' a solution before anyone says it. No one else. As Trevor might comment: "Aye, and there's the rub."