Boom Supersonic speeds past halfway point to breaking sound barrier (2025)

Boom Supersonic wasted little time proceeding with the fourth test flight of its XB-1 prototype aircraft, reaching on Friday a new top speed of Mach 0.617 — more than halfway to supersonic flight.

Blake Scholl, founder and chief executive of Boom, said the company remains on pace to break the sound barrier by the end of this year.

At Mach 1, the prototype can fly at the speed of sound, which is 761 miles per hour.

Each one-tenth beyond Mach 1 represents a 10% increase beyond the speed of sound, so Mach 1.1 is 10% faster, Mach 1.2 is 20% faster and Mach 1.3 is 30% faster.

The flight took place at the same Mojave Air & Space Port facility as other tests in March, August and on Sept. 13. Chief test pilot Tristan “Geppetto” Brandenburg was again at the controls, as he is scheduled to be for the first supersonic flight.

Boom reached a key milestone June 17 with the completion of its $500 million “superfactory” at Piedmont Triad International Airport. The Denver-based manufacturer has pledged to create at least 1,781 jobs at full production.

Boom’s demonstrator XB-1 aircraft is advancing through its flight test program to confirm its performance and handling qualities, with 10 subsonic flights planned before reaching supersonic speeds.

Among the key developments from the fourth flight are: maximum altitude of 16,150 feet; flight time of 48 minutes; and applied elevated g-forces of 2.78g in preparation for supersonic flight.

The flutter excitation system is a vibration device that Boom says “we can turn on in order to hit structural vibration modes deliberately before we would encounter them naturally in flight.”

The landing gear was retracted at a max speed of 225 knots, completing this portion of system testing. During future test flights, the team will retract the landing gear immediately after takeoff.

According to Boom executive Kathy Savitt, the Overture timeline at PTI remains as follows:

In July, Boom utilized Tuesday the influential U.K. Farnborough International Airshow to announce several new operational developments for its Overture aircraft and Symphony engine.

The latest developments involve:

Overture is expected to be the first large commercial aircraft to have a net-zero carbon impact from Day One, running on 100% sustainable aviation fuel.

The completion of the 170,000-square-foot factory shell at PTI represents a key symbolic milestone for one of the highest-risk, highest-reward projects in Triad and U.S. manufacturing history.

It’s also the most tangible, hands-on example of how far Boom is ahead of its eight global competitors in their common goal of resuming supersonic flight following the grounding of the Concorde in 2003.

The aircraft is being designed to carry 65 to 80 passengers at Mach 1.7 over water with a range of 4,250 nautical miles.

The initial Boom projection is producing up to 33 Overture aircraft annually at a projected price tag of $200 million.

In keeping with Boom’s ambitious nature since its January 2022 commitment to the PTI facility, Scholl said during the June ribbon-cutting ceremony the manufacturer plans to eventually double annual production, which would require another plant that could add another 600 jobs.

The “baseline” plan is to build one more just like it here, Scholl said.

“So, we’ll double up production, and we’ve got designs on the third one as well, that would fit right here on the same site.”