Boom Supersonic’s flight plan has to be measured in years

A small airplane that looks like a fighter jet but doesn’t bear a single weapon could be a pathfinder towards a reinvention of commercial aviation—or a flying footnote destined for a spot in a museum. Boom Supersonic’s XB-1 testbed airplane has high odds of being the first privately funded aircraft to shoot through the sound barrier. But that accomplishment won’t matter much unless this startup can then build its Overture airliner, a delta-winged, four-engined jet designed to fly at Mach 1.7 and cut many transatlantic flight times in half.  And then Boom will have to guide Overture through an environment that may be as tricky as transonic flight: safety certification on both sides of the Atlantic prior to revenue service that it hopes to see begin in 2030. Boom CEO Blake Scholl professes his confidence during an August visit to Boom’s facility at Mojave Air & Space Port in California’s high desert: “It’s not impossible, because it’s been done before.”  Boom’s flight plan Boom’s version of a minimum viable product is a single-aisle passenger jet optimized for a single market: the shorter set of trans-Atlantic flights that start with the lucrative New York to London route.  Overture will carry from 64 to 80 passengers, depending on seat layout, in an all business-class configuration and cut existing travel times in half: Instead of six to eight hours to go from Newark or JFK to Heathrow, depending on the direction, Overture should soar across the pond in three and a half.  Its service range of 4,250 miles would also cover such common trans-Atlantic routes as Washington to Frankfurt, while trans-Pacific routes would require refueling stops. United Airlines and American Airlines have placed orders with Boom, both with language stipulating that Overture must meet their own operational and safety requirements: United signed up for 15 in 2021, with American following a year later with a 20-plane order. Boom expects more orders to come, having built a 179,000-square foot structure in Greensboro, North Carolina, that will hold an assembly line capable of constructing 33 Overtures a year. Scholl says airlines should be able to print money with this jet. “The economic goal is to be highly profitable at the same kind of fares that people already pay in business class,” he says. “The break-even fare with 80% of the seats full is $3,500.” That’s well below typical transatlantic biz-class fares, but a veteran airline-industry analyst questions Scholl’s math. “The pilots are going to demand a hefty premium to fly a supersonic plane,” says Henry Harteveldt of Atmosphere Research. And, he notes, if airlines thought they could make that much more money from a supersonic airliner, they would have asked for one after the 2003 retirement of the pioneering Concorde. “Some airline somewhere would have gone to some aircraft manufacturer,” he observes. “We didn’t see that from Emirates,” Harteveldt says of the famously spendy Dubai-based airline.  Boom has also signed up the defense contractor Northrop Grumman to explore possible defense and government versions for purposes like VIP transport or express delivery of compact cargo—an answer, Scholl suggests, to a question like “how quickly can we get something to Taiwan?” The 2020s are not the 1960s But a new supersonic airliner would benefit from another half century of progress in aerospace engineering. “We’ve made improvements to fuel efficiency,” says Chris Combs, a professor of aerodynamics at the University of Texas at San Antonio. “We’ve learned things about reducing drag. There’s been a lot of materials-design advances.” For example, like such modern airliners as Boeing’s 787 and Airbus’s A350, Overture will be built from carbon-fiber composite structures instead of the traditional aluminum. That should make for a lighter and more fuel-efficient aircraft—and composites don’t expand nearly as much as aluminum when heated by supersonic speeds.   Overture’s turbofan engines, unlike Concorde’s much less efficient turbojets, will not require fuel-guzzling afterburners to break Mach 1 and will comply with today’s strictest noise regulations during takeoff and landing. Like Concorde, Overture will still generate a sonic boom, so it will max out at Mach .94 over land, about 20% faster than today’s airliners, and only accelerate past Mach 1 over oceans.  Scholl notes that Overture’s design speed of Mach 1.7—down from the Mach 2.2 the company touted back in 2016—is itself a compromise in favor of fuel efficiency.  Overture’s four Symphony engines, now in the later stages of design by a group of companies led by Florida Turbine Technologies, a subsidiary of the firm Kratos Defense, can also fly on 100% “sustainable aviation fuel” made without fossil fuels. If, that is, SAF suppliers can make enough of it. Admitting that “today there isn’t enough of it, and it costs too much,” Scholl says Boom is banking on advances in maki