Changes in how sharp the angle is where the dimple breaks from the surface of the ball and dimple depth provide room for the most variables. As a general rule of thumb, deeper dimples produce lower, flatter trajectories. Shallow dimples produce higher, ballooning trajectories. The key, Thurman says, is to create a dimple with enough depth to produce air turbulence around the ball as it rotates in flight. Thurman, along with technicians Susan Beachum and Donna Haynes and fellow engineer Ron Borecki, test a variety of ball designs at Wilson's research and testing laboratory, which sits at one end of a 13-acre driving range about a mile from the company's golf ball manufacturing plant.
Most companies come out with one or two new golf ball designs each year.
Ball designs that were in production four years ago are no longer being produced. Computers linked to the driving machine and to sensors along the fairway record the performance of each ball hit by the near-perfect swings of the mechanical golfer. Thurman works in an office adjoining the lab. Baskets of balls covered with lines, dots, and other felt-pen markings fill some corners in the office. With a few strokes on his computer keyboard, the engineer can bring up the image of his latest creation on the computer screen.