Throwing Physics a Curve

David Peters studies the aerodynamics of baseballs and helicopters


It’s March, and that means two things for David Peters—the start of the baseball season and appearing on television. Ever since his hometown St. Louis Cardinals won the 2006 World Series, he’s appeared regularly on local news to explain the mechanics behind curveballs and suchlike.

”I’m a ham—I don’t mind being the center of attention,” he says, laughing. ”And it gives us a hook for explaining science to the public.”

Peters holds a Ph.D. in aeronautics and astronautics from Stanford, worked for McDonnell-Douglas on the Apollo and Skylab space programs, and serves as the McDonnell-Douglas Professor of Engineering at Washington University in St. Louis. But he’s best known for the Pitt-Peters model, which helicopter flight simulators use to describe rotor-induced airflow in real time. And he brings the same high-tech creativity to the ballpark.

”Modern computational fluid dynamics codes can successfully predict the pressures and resultant motions of a baseball, just as they can for a F-18 fighter,” Peters says. ”The codes can predict the different motions of a curveball, fastball, knuckleball, slider, or changeup, since each has a different spin that results in a different pressure and flow field. These types of predictions were not possible until recently. Based on this, some Japanese aerospace engineers have been trying to use aerospace theory to develop a brand-new pitch.”

See Peters in action at