Reducing CostsThe problem, of course, is that wind tunnels aren't cheap. In order to reduce the cost of construction from stratospheric to reasonable levels, Eaker had to improvise. Fortunately, his experience as an aerodynamicist allowed him to do all the design work himself. One of the most important characteristics of the design is that although Eaker's tunnel fits full-scale race cars, it is actually quite small. Most tunnels are a closed circuit, cycling the moving air through a loop over and over again. Eaker's design is an open circuit. The tunnel fully eliminates three-fourths of the traditional tunnel; instead of a circle, it is a straight line. Air is sucked in one end and exits out the other end approximately 150 feet away. A smaller tunnel means less construction costs, fewer maintenance costs, and a smaller building to house the tunnel.
Other unique design features are the 22 fans stacked in a precise alignment to move the air through the tunnel. Before Eaker built his tunnel, the accepted thinking was that a wind tunnel required a single, gigantic fan in order to move air through a tunnel in a consistent, linear manner. But giant fans of the quality and power required for wind-tunnel work cost hundreds of thousands of dollars. Instead of accepting conventional wisdom, Eaker devised a layout using readily available fans that can move the air as efficiently without breaking the bank. The fans are actually placed at the end of the tunnel and pull, not push, the air through it. As the air enters the large opening in the tunnel, it is only travelling approximately 30 mph. The tunnel funnels the air down into a smaller area so that when it reaches the testing area of the tunnel, it is travelling 130 miles per hour. The tunnel opens back up so that when the air reaches the fans, it has slowed back to just over 30 mph. After the air exits, it is still trapped inside the building that houses the tunnel and simply makes its way back to the tunnel's entrance at a stately 10 mph.
Not only did Eaker design the wind tunnel himself, he very nearly built it himself. Early on, he and a few employees, working in his garage, cut panels for the tunnel's intricate floor. When they ran out of space, they moved to a 25x25-foot building in a self-storage facility. The wooden ribs that hold all the panels in place all required custom cuts because of the specific curves that make up the tunnel's interior walls-they were all cut by Eaker's minister, who is an amateur woodworker, in his workshop. Finally, Eaker wrote all the complicated software that tracks all six possible forces on a car (drag, downforce, side force, roll, pitch, and yaw). A lot of the design for the tunnel is unconventional, but it works. "I don't know how most people build wind tunnels," Eaker says. "I just knew how we had to build ours to make the most of our available resources."
Now operating as the Aerodyn Wind Tunnel, Eaker's operation is working at near capacity two shifts per day. Race teams sign up for the day session, which requires booking the facility for 10 hours (7 a.m. until 5 p.m.) at $1,250 an hour. A second, evening shift is also available (from 6 p.m. until midnight or through 4 a.m., depending on a particular team's needs) to meet demand. A staff of at least three technicians is on hand to assist the race team, which typically will send between three and six crewmen, to test. Eaker's team will set up the car in the tunnel and run the facility, but they will not offer any advice on what changes will help or hurt a car's aero characteristics. "It's the only way we can avoid any appearance that we are giving away information we may have learned during another team's test," Eaker explains. "We will help a team test anything they want. We're here to run the tunnel for them, but we won't give away information."