It is known that commercial supersonic flight is on its way back, but the fact that it can be done without a sonic boom is a revelation. Boom Supersonic, a company at the forefront of supersonic aircraft design, recently unveiled an important innovation: “Boomless Cruise“. This approach allows the sound barrier to be broken without causing the shock wave to reach the ground.
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The XB-1 supersonic test
On January 28, 2025, Boom Supersonic’s XB-1 technology demonstrator successfully completed its first supersonic flight, exceeding Mach 1 three times without producing an audible boom on the ground.
This achievement was made possible by the physical phenomenon known as Mach Cutoff, which deflects shock waves into the atmosphere, preventing them from reaching the ground.
To create this effect, supersonic flight must occur at precise altitudes and speeds that vary with atmospheric conditions.
Because sound travels more slowly at higher altitudes, when an aircraft breaks the sound barrier at these altitudes, the resulting boom cannot reach the ground. As the shock waves travel downward, the increased speed of sound in denser air causes them to refract upward instead.
However, factors such as temperature and wind also affect sound propagation. This means that the optimal altitude and speed for a supersonic aircraft to avoid producing a noticeable boom depends on the specific atmospheric conditions at any given time.
“The actual challenge is getting very accurate atmospheric forecasts on temperature and on wind – computing the practical Mach-cutoff flight speed is pretty straightforward from there”
— Bernd Liebhardt at the German Aerospace Center
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Demonstrating Boomless Cruise
During the XB-1 flight test, special microphones strategically placed along the flight path showed that the sonic booms did not reach the ground as the aircraft flew at Mach 1.12.
Boom used the XB-1’s supersonic flight data to validate the sonic boom models and refine the algorithms that predict Mach-limit operation.
The data was further reinforced by XB-1’s second supersonic flight, which took place on February 10, 2025. The flight pushed the top speed reached to Mach 1.18 and provided more data on the shockwave. The flight was XB-1’s 13th and final, as it has now served its demonstration purpose.
The success of the test campaign demonstrates the scalability of the technology and sets the stage for the future of commercial supersonic flight without noise restrictions.
These results show that supersonic flight is possible without the disturbance of a sonic boom, opening the way for supersonic travel over land aboard Boom’s supersonic aircraft, Overture.
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Overture: the future of commercial supersonic flight
Boom Supersonic’s Overture airliner will be the first to use this technology for commercial flights. Optimized for speed, Overture will be able to reach supersonic speeds without emitting an audible boom, resulting in much shorter flight times.
Boom aimed to fly Overture at Mach 0.94 over land masses, nearly 20% faster than today’s subsonic aircraft, while only exceeding Mach 1 over oceans, reaching a top speed of Mach 1.7, about twice the speed of today’s commercial jets.
However, measurements from the XB-1’s supersonic flight indicate that Overture can travel up to 50% faster than conventional aircraft over land without producing a significant sonic boom.
The Symphony engine, designed specifically for Overture, is a major contributor to this advancement. This propulsion system is designed to generate effective thrust in both the transonic and supersonic phases, allowing high speeds to be maintained without compromising fuel efficiency.
In addition, Overture’s superior autopilot will be able to maintain the fastest possible speed based on atmospheric conditions while avoiding an audible sonic boom.
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Next steps
Boom Supersonic has already received 130 orders and pre-orders for Overture from American Airlines, United Airlines, and Japan Airlines. Construction of the Overture Superfactory in Greensboro, North Carolina, was completed in 2024, with a production capacity of up to 66 aircraft per year.
The next step in the program is the Symphony engine test phase, which is scheduled to begin in late 2025. These tests will be critical in determining the performance of the compressor, combustor, and turbine, as well as fine-tuning the engine design prior to certification.
The adoption of Boomless Cruise technology is a significant advancement for the supersonic aircraft industry. Boom Supersonic’s Overture promises to transform air travel by making travel faster and cheaper while eliminating the disadvantages of previous models.
If all goes according to plan, commercial supersonic travel may be back sooner than we think.
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