BOOM! XB-1 breaks sound barrier

Boom Supersonic’s subscale XB-1 demonstrator has broken the sound barrier for the first time, achieving Mach 1.1122 in the same hallowed Mojave Airspace where Chuck Yeager achieved the world’s first supersonic flight in 1947.

boom mojave supersonic run

Boom Supersonic’s XB-1 test aircraft has achieved supersonic success, with its scaled demonstrator reaching Mach 1.1122 (652 KTAS) during a milestone mission from California’s Mojave Air and Space Port less than a year after its first flight. Achieving a maximum altitude of 35,920 feet in the supersonic corridor above Mojave, the aircraft reached supersonic speed three times before being safely recovered to base.

Progress has certainly been speeding up over the last year for Boom Supersonic’s flight test programme, with the XB-1 demonstrator project having now achieved its objective of reaching supersonic speeds. “A small band of talented and dedicated engineers has accomplished what previously took governments and billion dollars,” explained Boom Supersonic founder and CEO Blake Scholl.

This is also the first time a supersonic jet has been developed by an entity other than a nation state and represents the first civil supersonic aircraft in American history.

XB-1 is 62.6 feet long with a wingspan of 21 feet and is powered by three GE J85-15 engines with a combined max thrust of 12,300 pounds of force. Providing the foundation for the upcoming Overture supersonic airliner, Boom explained that XB-1 was designed to validate key technologies – including an augmented reality vision system for takeoff and landing, digitally-optimised aerodynamics, carbon fibre composites and supersonic air intakes.

The milestone flight was streamed from a Northrop T-38 chase aircraft through the integration of a Starlink Mini phased-array antenna paired with an aviation data plan, which Boom had previously tested driving up and down the runway mounted to a 1995 Mazda Miata. The online livestream was hosted by former Concorde Chief Pilot Mike Bannister, a longstanding supporter of the venture.

XB-1 was piloted by Boom Supersonic Chief Test Pilot Tristan ‘Geppetto’ Brandenburg, who upon getting out of the aircraft, commented: “that’s the best she’s ever flown”. Thanking every team member instrumental in the achievement, he added: “Our discipline and methodical approach to this flight test programme created the safety culture that made a safe and successful supersonic flight possible.”

Lessons leveraged from the programme will now be used to develop Boom’s supersonic ‘Overture’ airliner, slated as the successor to Concorde, which will carry 64-80 passengers at Mach 1.7. Expected to enter service by the end of the decade, Boom’s pre-order book of 130 units already includes agreements with American Airlines, United Airlines, and Japan Airlines. Speaking at Farnborough International Airshow in 2024, Scholl described the iconic Concorde as “the story of a journey started  but not yet finished,” concluding: “we have time to do this well”.

“We’re not going to stop until everyone can benefit from this,” concluded Scholl. “This afternoon we celebrate, tomorrow it’s back to work. It’s time to go big…. To scale it up. And bring back supersonic flight in a mainstream way”.

Although the XB-1 made its maiden flight on 22 March 2024, progress then seemed to stall before Scholl explained in July that the campaign was to shortly recommence. Highlighting how the first flight produced “better than forecast handling qualities in pitch and yaw,” the roll characteristics – allegedly described by the first test pilot as “a little bit exciting” – were addressed with the implementation of a new system.

With hew chief test pilot ‘Geppetto’ (who flew the chase aircraft for the inaugural excursion) on board, flights then recommenced at pace. These continued to validate and log data points, and negotiating minor issues along the way (such as inconveniences with a sub-optimal Flutter Excitation System on flight four). During test flight 10, on 19 December 2024, XB-1 reached Mach 0.95.

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