Aerodynamics on Land: Aiming for 800 M.P.H.

When Ed Shadle was growing up, you could buy a junker for a couple hundred dollars, pound out the dents, drop a big engine in it, paint it candy apple red, take it to the outskirts of town and race from stoplight to stoplight until the cops told you to go home.

The vehicle must have at least four wheels — two of them steerable — and be back at the original start line within 60 minutes. And that’s it. “You race Formula One or Nascar, the rule books are as thick as the Bible,” Mr. Shadle said. “For this, the rule book is a half-page long.”
But consider the challenges. Rubber tires turn to molten licorice at anything above 350 miles per hour, so the Eagle uses custom-built, single-billet aluminum alloy wheels, grooved for traction on soft surfaces. They will not work on asphalt or concrete. The brakes are special alloy magnets that generate 4,700 brake horsepower as the magnetized drum approaches the moving aluminum wheel, slowing it gradually without ever locking up.
The big imponderable is the sound barrier. In the sky, the shock wave simply dissipates. But on land, it bounces off the ground and can flip a racer into the air. Since each car is unique, the problem has to be solved differently every time. Computer modeling is important — but only up to a point.