In his recent victory at the US Masters tournament, golfer Danny Willett unknowingly received an assist from an unexpected source –- The Boeing Co.’s computational fluid dynamics (CFD) software.
CFD software, more commonly used on airplanes and automobiles, improved the aerodynamics of Willett’s driver, giving it greater club head speed and stability. “With CFD, we can analyze the drag associated with the club’s crown, face, sole, or hosel,” said Evan Gibbs, research and development manager of woods at Callaway Golf, which makes the new driver. “And we can see how much it impacts the club head speed.”
The resulting club, Callaway’s XR 16 Pro Driver, is said to offer a boost of about 1 mph to 2 mph. It’s being employed, not only by Willett, but golfer Lydia Ko, who used it to win the Ladies Pro Golf Association’s (LPGA) ANA Inspiration Tournament April 3.
See the XR 16 Pro in action by clicking on the image below.
Pro golfer Danny Willett won the 2016 Masters using a driver designed with computational fluid dynamics software from The Boeing Co. Willett first used Callaway Golf’s XR 16 driver in a February tournament in Dubai, which he also won.
(Source: Callaway Golf)
The team effort between Boeing and Callaway was years in the making. Callaway’s engineers worked with the giant aircraft manufacturer on composite clubs a decade ago, during Boeing’s 787 design. Recently, they returned for the aerodynamics collaboration. “We’d been looking at aerodynamics for many years, and we wanted to take it to the next level,” Gibbs told Design News. “To do that, we knew we needed to improve our understanding of aerodynamics, so we brought in Boeing.”
The aerodynamic challenge, common to the design of all drivers, is to reduce the drag that’s created whenever a golfer swings the short, stout head of a wood at high velocities. Specifically, the issue is pressure drag. Pressure drag is created whenever air flows across the face of the club and strikes the crown. Once that happens, the flow separates from the club head, creating a turbulent wake on the trailing side that sucks the club head backward, slowing its forward motion. That phenomenon is common, engineers say, because a wood is a so-called “bluff body” –- a flat surface in front of a short, rounded shape.
Boeing’s in-house CFD software enabled Callaway and Boeing to create a so-called “trip step” (a small step shape near the crown) in the front of the club head, prior to the point where the flow separates. “What we were trying to do is delay the separation,” Gibbs said. “We wanted to keep the flow attached to the club head longer, which minimizes the wake.” By doing so, he said, they could reduce the pressure drag behind the club.
To test whether the trip step worked, the engineering team used a robot to swing the club. By employing clubs of identical length and weight on the robot and then measuring swing velocity, they were able to determine that club head speed increased by 1 mph to 2 mph, Gibbs said.
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At the same time, the engineering team was able to use the CFD software to optimize the shape of the club head to provide it with more “forgiveness” –- that is, more stability on off-center hits. “Often times, the same elements that make a club super fast also make it less forgiving, and vice versa,” Gibbs said. “Being able to combine those two things in such a unique way is what makes this driver different.”
The team effort served both companies well, Gibbs said. Callaway engineers learned about aerodynamics, while Boeing engineers were exposed to a design process that had to be completed in months, rather than the 10 to 12 years that are typical for the design of a giant aircraft.
”We’ve worked with consultants before, but this is the first time we’ve used an outside company to design a specific feature on a club,” Gibbs said. “Being able to tap into their knowledge gave us a huge advantage.”
Most of all, though, the engineering teamwork provided a boost for Willett, whose drives averaged 305 yards in the Masters’ final round. “It did exactly what (Callaway tour reps) said it was going to do,” Willett is said to have told Callaway. “It gave me a little more ball speed and helped me control my ball flight.”
Senior technical editor Chuck Murray has been writing about technology for 32 years. He joined Design News in 1987, and has covered electronics, automation, fluid power, and autos.