Breaking the ‘Boom’
Like some prodigious inventors, Michael Buonanno (AE ’01) truly understood the importance of his project when his first child was born.
He’d just started working on a new supersonic aircraft design for NASA, and one evening at his southern California home, he was trying hard to convince his newborn to catch some sleep. He eventually succeeded—then imagined a plane flying overhead, breaking the sound barrier. All his effort, destroyed with an indelibly distinct sonic boom.
“That’s when it went from, ‘What’s the big deal?’ to, ‘Absolutely, this would not be acceptable,’” Buonanno laughs.
His decade-long project, the X-59, is the pinnacle of his passion: from a kid who loved drawing airplanes all the way to his current gig as an air vehicle lead and fellow at Lockheed Martin, he’s been fascinated by advances in aviation. Advances which, along one vector at least—speed—halted in the 1960s. Eventually, sonic booms led to international bans on speeds above roughly 700 mph over land.
But Buonanno, heading a multidisciplinary team under a NASA contract, wants to change that.
“We could get out of this stagnant period that we’ve been in since the 1960s, where air travel has not gotten any faster and really has gotten slower,” the life-long aircraft designer says. “We’ll get where we want to go more quickly.
“We’ll move away from the sonic boom altogether.”
HONORING A LEGACY
Born and raised in upstate New York, Buonanno became fascinated with planes after an influential elementary school history teacher spoke on the importance of aviation during World War II. Shortly thereafter, he devoured a book that his mother bought on the subject, cover to cover.
“I was convinced at a young age that I wanted a career in aviation. I really had no ambiguity,” Buonanno says.
He initially wanted to be a pilot, but an accident at age 11, when he fell through a glass door and almost bled out, resulted in some loss of mobility in one of his arms. So he pivoted to engineering.
After graduating from Illinois Institute of Technology in the midst of a weak job market, he decided to pursue graduate school, culminating in a Ph.D. from Georgia Institute of Technology in 2005. He started at Lockheed Martin immediately after graduation as a conceptual design engineer. There, he became enmeshed in one of the most highly specialized units in the company.
Lockheed Martin’s Advanced Development Programs, also known as ‘Skunk Works,’ got its pseudonym during World War II when the company’s Burbank, California facility grew from 3,000 people to about 100,000. Pressed for space, they placed a specialized unit in a circus tent, right next to a chemical processing plant.
The unit was charged with tackling seemingly impossible “special mission needs,” with its first project being the P-80, the first United States jet fighter to go into large production. Other hallmarks include the U-2 spy plane and Buonanno’s favorite, the SR-71.
“It was designed for one thing: to go fast. And it did that very successfully,” he says.
Not only was the SR-71 sleek, and in Buonanno’s mind, beautiful, it was the pinnacle of speed—the fastest plane ever flown. Or, with all the caveats, the fastest manned, air-breathing airplane. Built in 1963 and capable of Mach 3—three times the speed of sound—it was where world-wide advances in speed stopped.
“The progress in speed was more or less like the progress in computing power: It roughly doubled every decade, from 1903 [when the Wright Brothers flew 36 meters in 12 seconds] until the 1960s,” Buonanno notes.
That’s when speeds breached the 767 mph sound barrier, and progress came up against consequence. The environmental impact, or “acoustic disturbance,” of sonic booms made such speeds over land untenable. Sonic booms stay with aircraft as they fly, trailing a 50-mile-wide swath of acoustic shock. Internationally, there are now bans on going faster than the speed of sound over any land mass.
Which brings Buonanno to his current project.
MUFFLING THE BOOM
For the last decade, Buonanno has been trying to figure out how to break the sound barrier over land. Quietly.
Shock waves are a near-instantaneous rise in pressure and temperature. Each individual surface, edge, antennae, or crevasse on an aircraft creates a small shock wave.
“Many of our tactical fighters—F-16s, F-18s—when they go supersonic, all those shock waves coalesce, focus together before the shock waves hit the ground. So instead of a series of small disturbances, they focus on one very loud double-bang,” Buonanno notes.
The goal of the X-59 project is to disperse all those shock waves over a gradual time frame, so people on the ground don’t begrudge the muffled “boom.” The PLdB (a different industry measure of decibels) of a Concorde airplane breaking the sound barrier is 108. The X-59 is projected at 75.
“You can’t make it [the sonic boom] completely go away, but you can make it so quiet that it blends into the background noise of everyday life,” he says.
“The longer you spend in this project, the more you appreciate we could potentially change the way the world travels,” says Ryan Reynolds, senior program manager for the X-59 project.
Reynolds says Buonanno, who he has known since they both started at Lockheed Martin in 2006, is a calm cornerstone for the team on the high-pressure project: smart, a good listener, and supportive.
“In the heat of schedule and cost pressure and technical challenge, he manages to keep more of a family feel than a hierarchical one,” Reynolds says.
They’re now building an experimental aircraft, or X-plane, which they hope to fly later this year. If successful, Buonanno says, NASA—working with international regulatory organizations—could potentially work to remove the flat-out ban on supersonic travel over land.
“If you fly from the west to east coast [of the U.S.], which I do quite regularly, it now takes six hours. Round trip for a meeting is basically three days,” he says. Supersonic travel over land could potentially cut travel time in half, shortening such trips by a day, even two.
“It’ll mean that we can get back on the trend of continuous advances in terms of travel speed until the 1960s,” Buonanno says. “And it’s not going to wake up your sleeping baby.” •