The XB-1 aircraft from the American Boom Supersonic has opened 2025 by successfully completing its 11th test flight on January 10. It is now approaching its first supersonic test. During 2024, the demonstrator has already completed ten test flights at the Mojave Air & Space Port in the California desert. During the 11th flight test, which lasted 44 minutes, Boom's chief test pilot, Tristan "Geppetto" Brandenburg, took the XB-1 up to an altitude of 29,481 feet. The aircraft once again reached a maximum transonic speed of Mach 0.95, exceeding the cruising speed of modern airliners. "Transonic" speed is defined as speeds just below the supersonic limit, corresponding to Mach 1, according to a press release.

Objectives of the 11th test

The main purpose of this test, the company explains, was to expand the dynamic pressure range experienced by the aircraft, reaching 383 Knots Equivalent Airspeed (Keas), a value higher than that expected for the first supersonic flight. "This represents the maximum level of dynamic pressure that the XB-1 will encounter, even exceeding the parameters estimated at Mach 1.1. Dynamic pressure, determined by the speed and density of the air, plays a crucial role in the performance of an aircraft approaching supersonic speeds. As the speed increases, especially at low altitude, dynamic pressure increases significantly, affecting the stability and maneuverability of the aircraft. For this reason, during flight tests, each parameter -both dynamic pressure and Mach number- is increased gradually and in a controlled manner to ensure safety and precision".

Countdown to the 12th test

Brandenburg will take the XB-1 to 34,000 feet for the most ambitious flight in its history: “the world’s first independently developed supersonic jet will break the sound barrier in the Bell X-1 Supersonic Corridor and the Black Mountain Supersonic Corridor in Mojave, California", the company says. The aircraft will fly for about 30 to 45 minutes, approximately on January 28 at 6:45 am PST/9:45 am EST/2:45 am GMT. The flight will be live-streamed. The supersonic livestream will be hosted by former British Airways Chief Concorde Pilot Mike Bannister, who has logged nearly 7,000 supersonic hours on Concorde. He will be joined by experienced members of the XB-1 team, Chief Flight Test Engineer Nick Sheryka and Boom consultant and former Chief Engineer Greg Krauland, to discuss each key moment of the test.

Since the model’s historic first flight on March 22, 2024, the demonstrator has made significant progress in its test program. The XB-1 represents a milestone in Boom’s research and development toward Overture, the future supersonic airliner designed to offer fast and efficient flight. This technology demonstrator integrates some of the most advanced solutions available, including:

- Digitally optimised aerodynamics, to minimise drag and maximise efficiency;

- Carbon fiber composite materials, combining lightness and strength;

- Advanced air intakes for supersonic engines, for better airflow management;

- Augmented reality vision system, which ensures optimal visibility during take-off and landing.

With these developments, the XB-1 lays the foundation for a future where supersonic flight can become part of the everyday reality of commercial aviation, without sacrificing safety or sustainability, the note concludes.