With a refined design announced on Tuesday for its Mach 1.7 Overture jet, Boom Supersonic’s dream of reviving commercial air traffic exceptionally fast seems a little more real. But this update to Overture, a small plane in the making since 2016, still leaves an important part undefined.
The biggest configuration change Denver Boom revealed during the Farnborough International Airshow outside London an additional engine has been added: the Overture now has four instead of the three of the previous design.
The new design places each engine in a separate pod below Overture’s delta wing and features a carbon composite fuselage that tapers above the wing for better supersonic aerodynamics (known as a “area rule” design). This makes it less like the Concorde jets that crossed the Atlantic at speeds just above Mach 2 until 2003 and more like the Air Force’s Vintage 1956 B-58 Supersonic Bomber.
“The aircraft is now designed for manufacturability and maintenance,” says Boom CEO Blake Scholl londonbusinessblog.com. “The tail-mounted engine in the old design would have been difficult to access and maintain.”
He notes that a twin-engine design, something shown in a 2016 render from Boom, would require larger-diameter engines than the company would hope to use for supersonic flight.
With the switch from three engines to four, the Overture jet’s range — 4,890 miles — and fuel economy won’t change, Scholl says: “Everything we’ve said about fuel efficiency about the planes over the years remains true.”
Boom continues to praise Overture’s ability to fly on 100% renewable jet fuel, which can be made from sources such as used cooking oil or carbon dioxide extracted from the air with direct air capture machines.
But the identity of the company that will build those engines remains up in the air. Tree signed a 2020 venture with Rolls-Royce to investigate whether any of that manufacturer’s current engines could be modified, but Scholl won’t say whether Rolls would build Overture’s engines. “We’ve been working behind the scenes on the engine for a long time because it’s a fundamental part,” he says.
In a conversation on the Collision conference in Toronto in June, Scholl had previously indicated that the company could modify a current subsonic engine and that Boom had “multiple options that are quiet, that are economical.”
Tuesday’s announcement states that the Overture will take off and fly without using noisy afterburners, something the Concorde needed and bothered many people on the ground. As a resident of the then rural area next to Washington Dulles International Airport told the Washington Post in 1977: “The horses panic and run like mad across the field as the Concorde passes.”
Boom, however, isn’t focused on reducing the loud sonic boom caused by Overture — a subject of recent government and industry research — and so will limit supersonic flight to over oceans, at land speeds as low as just below Mach 1.
“If you choose the gentler levels of sonic boom, that comes with an efficiency debt,” Scholl says. “We’re focusing all our efforts on fuel efficiency and putting the sonic boom where no one will hear it.”
Boom predicts that a flight from New York to London would take three and a half hours (from about seven o’clock now), while Seattle would fly to Tokyo in four and a half (from about 10 hours). However, a refueling stop is required for departures to Japan from much further south on the west coast.
Boom’s announcement also suggests a change to Overture’s passenger accommodations. Previous Boom renderings showed only one seat on each side of the aisle, but Scholl says that would change to a two-by-two layout in the forward section of the cabin, then two-by-one in the narrower fuselage above the wing. The jets are expected to have a range of 65 to 80 seats.
“It’s 65 in a very luxurious interior,” says Scholl. “At 80, it’s still fun, but it’s not as spacious. We are working on an interior update that we can share earlier next year.”
Boom’s announcement also mentioned a partnership with defense contractor Northrop Grumman to develop “a special mission variant for the US government and its allies.” Scholl describes a possible government use case: “How many allies can the Secretary of State visit in a day?”
Boom’s most high-profile customer remains United Airlines, which signed a deal to purchase 15 Overture jets in 2021 — provided Overture meets “United’s demanding safety, operational and sustainability requirements,” the airline noted in a statement. his announcement. United has options for another 35, while Japan Airlines placed options for 20 overtures in 2017.
Boom’s next step will be to fly its smaller XB-1 prototype, a step it once hoped to make by the end of 2017. That jet rolled out of its Centennial, Colo., late last year for testing on the groundwith test flights scheduled for later this year.
Next comes groundbreaking work for the plant in Greensboro, NC, followed by construction of the first Overture jet from 2024. Five years will then be left to get the aircraft in flight tests, certified by government regulators and delivered to airlines to meet the planned schedule. Boom’s deadline in 2029. welcoming paying passengers on board.
That may seem like a lot of runway. But in the safety-driven, test-driven culture of commercial aviation, Boom will have to perform many tasks precisely to achieve takeoff speed on the planned schedule.