Throwing Physics a Curve

David Peters studies the aerodynamics of baseballs and helicopters

1 min read

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

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​​Why the World’s Militaries Are Embracing 5G

To fight on tomorrow's more complicated battlefields, militaries must adapt commercial technologies

15 min read
4 large military vehicles on a dirt road. The third carries a red container box. Hovering above them in a blue sky is a large drone.

In August 2021, engineers from Lockheed and the U.S. Army demonstrated a flying 5G network, with base stations installed on multicopters, at the U.S. Army's Ground Vehicle Systems Center, in Michigan. Driverless military vehicles followed a human-driven truck at up to 50 kilometers per hour. Powerful processors on the multicopters shared the processing and communications chores needed to keep the vehicles in line.

Lockheed Martin

It's 2035, and the sun beats down on a vast desert coastline. A fighter jet takes off accompanied by four unpiloted aerial vehicles (UAVs) on a mission of reconnaissance and air support. A dozen special forces soldiers have moved into a town in hostile territory, to identify targets for an air strike on a weapons cache. Commanders need live visual evidence to correctly identify the targets for the strike and to minimize damage to surrounding buildings. The problem is that enemy jamming has blacked out the team's typical radio-frequency bands around the cache. Conventional, civilian bands are a no-go because they'd give away the team's position.

As the fighter jet and its automated wingmen cross into hostile territory, they are already sweeping the ground below with radio-frequency, infrared, and optical sensors to identify potential threats. On a helmet-mounted visor display, the pilot views icons on a map showing the movements of antiaircraft batteries and RF jammers, as well as the special forces and the locations of allied and enemy troops.

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