collapse into a single shock wave and create a percussive
boom that sounds like a thunderclap. The airplane’s tail
then creates a second shockwave, and a second boom. No
one aboard hears the cacophony, but everyone along the
flight path can, even when the jet is cruising at altitudes be-
yond 50,000 feet. The Concorde generated a boom loud
enough to rattle windows, startle people, and frighten ani-
mals. This prompted the U.S. and many European nations
to ban overland flights by supersonic airliners.
Boom isn’t concerned about the boom because it is fo-
cusing on oceanic flights. Aerion and Spike don’t have the
luxury of ignoring the problem, because bizjets must be
capable of flying everywhere. While Aerion aims to quiet
its airplane by flying it at a speed and altitude that can
keep the boom from reaching the ground, Spike thinks
aerodynamic sculpting can minimize the racket. Re-
search by Lockheed Martin’s famed Skunk Works division
suggests this would work if the craft flies at a prescribed
altitude and with the right attitude, so to speak.
Spike will almost certainly crib from Lockheed’s on-
going work with NASA on its X-59 QueSST, a “quiet”
supersonic jet intended to prove the viability of boom-
suppression tech. Mitigating the sound requires directingon the project, drawing heavily from government coffers
to pull it off. Airbus needed 17 years and some $25 billion
to bring the A380 to market, while Boeing devoted eight
years and at least $32 billion to the 787 Dreamliner.
Still, no less an aviation luminary than Virgin Group
founder Richard Branson is betting that Boom can pull it
off. His company has offered Boom engineering, manufac-
turing, and flight-test assistance—and preordered 10 jets.
AERION AND SPIKE HAVE
in some ways even loftier ambi-
tions than Scholl’s outfit: They
want to quell the sonic boom,
something that has vexed gener-
ations of aeronautical engineers.
Aircraft compress the air
around them as they move
through the sky, violently jamming together the mole-
cules that comprise Earth’s atmosphere into pressure
waves. These waves, which radiate around the airplane
like rings from a pebble dropped in a pond, typically dis-
sipate without much fuss. But when a craft exceeds the
speed of sound, it races ahead of those ripples, which
POPSCI.COM•SPRING 2019 91Plane Cool
(1) A mock-
up of Boom’s
demonstration
flyer;
(2) the mighty
Concorde;
(3) the Soviet
Tupolev Tu-144.A