Boom Supersonic’s prototype passenger jet, the XB-1, has officially gone supersonic. The human-piloted demonstrator hit Mach 1.122 (or 1,385 kilometers per hour) at a 10.7-kilometer altitude over the Mojave Desert on 28 January—marking a major step in Boom’s plans to market commercial aircraft flying roughly twice as fast as today’s subsonic airliners by 2030.
In addition to proving XB-1 could break the sound barrier, the test validated critical technologies that will be scaled up for Overture, Boom’s Mach 1.7 jet. Designed to carry 64 to 80 passengers at altitudes up to 18 kilometers, Overture could cut flight times in half for many common transoceanic routes. Boom is eyeing hundreds of “supersonically viable” options, such as Tokyo to Seattle (reducing an 8.5-hour flight to about 4.5), Los Angeles to Sydney (from 14.5 to 8.5 hours), and New York to London (from 6.5 to 3.5 hours). Over land, the aircraft could fly about 20 percent faster than current commercial jets, at Mach 0.94.
Boom tells IEEE Spectrum it’s preparing for a second supersonic test on 10 February (weather permitting) at California’s Mojave Air and Space Port, during which the company is partnering with NASA for specialized photography. The mission aims to break the sound barrier again and continue collecting data on XB-1’s performance and handling qualities, which affect the pilot’s ability to control the aircraft under various flight conditions.
The successful test followed a carefully structured program to accelerate through subsonic, transonic, and supersonic speeds. Jeff Mabry, Boom’s vice president of XB-1 and Overture, says this involved checking handling qualities, flying qualities, and aircraft systems operation at incrementally increasing speeds and altitudes to ensure safety and performance. “It is always in our hearts and minds that a human pilot is in XB-1, not a drone,” Mabry says.
XB-1 has completed 12 test flights since March 2024, each evaluating critical components and capabilities such as the landing gear, environmental control system, and operating altitudes. Engineers also tested and modified the flutter excitation system, which intentionally vibrates the aircraft to assess its structural response.
[embedded content]- YouTubeHappening Now. Watch XB-1’s supersonic test flight in real-time. Join us and see XB-1 break the sound barrier from the viewpoint …
Engineering a Supersonic Jet
XB-1’s supersonic flight marks the first independently developed jet to break the sound barrier and the first human-piloted civil supersonic flight in decades.
If successful, Overture could become the first commercial supersonic airliner since the Concorde, a Mach 2 aircraft developed in the 1960s by the British Aircraft Corporation and France’s Sud Aviation. The Concorde, which entered service in 1976, could cross the Atlantic in under three hours, but high operational costs, inefficiency, and excessive noise made it economically impractical—ultimately leading to its retirement in 2003.
“As we saw with Concorde, we expect strong demand from North America to/from Europe, but what is unique to Overture is its global operability, with meaningful time savings across routes in all regions of the world,” Mabry says.
Boom says its Symphony turbofan engine will be quieter than Concorde’s deafening afterburners were.Boom Supersonic
XB-1 and Overture incorporate several advancements missing from Concorde: Instead of Concorde’s droop nose design for runway visibility, Boom uses a head-worn augmented reality vision system with external cameras and sensors. Overture’s medium-bypass turbofan engine, Symphony, will run on sustainable aviation fuel and produce noise levels comparable to subsonic jets, unlike Concorde’s deafening, CO2-emitting afterburners.
Supersonic jet design presents unique engineering challenges, particularly in heat management and structural integrity. Concorde’s airframe could expand by up to 25 centimeters during flight due to Mach 2’s extreme temperatures. The craft was coated with a white paint designed to accommodate that stretching.
Mabry says Overture’s structure will experience thermal stresses, especially where composite and metallic parts meet. “The fuselage length will not grow like Concorde during cruise, but metallic parts will want to expand a bit at high temperatures or shrink at low temperatures, compared with the adjacent composite structural elements,” Mabry says. “These stresses are being considered [in the design] and will be verified during testing.”
Most of the structure uses lightweight carbon fiber composites, which exhibit lower thermal expansion than Concorde’s aluminum alloys. Composites enhance aerodynamics and fatigue resistance, a reason why they’re used in modern airframes like Boeing’s 787 (50 percent of the main structure) and Airbus’s A350 (53 percent).
Boom has optimized Overture for Mach 1.7, a speed intended to balance performance and material constraints. According to Mabry, the structure’s maximum temperatures during Mach 1.7 cruise allow for the use of lightweight composites, which are easier to shape into a low-drag, aerodynamic design than aluminum.
Next Steps
Boom sees a significant unmet market for supersonic transoceanic travel, claiming Overture could open 600 routes to hundreds of millions of travelers while being profitable for airlines at fares similar to first- and business-class tickets. (Rates will ultimately be left up to the airlines.)
Boom’s supersonic jets won’t rely on a droop-nose design like the Concorde had.Boom Supersonic
The company aims to secure U.S. Federal Aviation Administration and European Union Aviation Safety Agency certification by the end of the decade, clearing Overture to carry passengers. Orders currently total 130 aircraft, including from American Airlines, United Airlines, and Japan Airlines. While the company didn’t disclose specific cost estimates for Overture, it confirmed its previous projection of US $200 million per unit remains unchanged.
“Our goal is to roll out the first Overture in three years and be flight testing in four,” says Boom CEO Blake Scholl. In about 18 months, Boom plans to start producing aircraft at a new superfactory in North Carolina. The facility will initially output 33 units annually, then scale up to 66.
Meanwhile, about 50 engineers, technicians, support staff, and pilots are working on XB-1’s flight test program. Scholl expects to begin engine core tests on Symphony by late 2025 to analyze the performance of the compressor, combustor, and turbine section.
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