Throughout the 20th century, the aerospace industry was consumed by the pursuit of speed, culminating in supersonic commercial air travel.
From the early pioneers in the 1910s and 20s, through the beginning of commercial airliners in the 30s and 40s, and then into the mass adoption of air travel in the 50s and 60s, the speed of flying was the number one driver of growth. Each new aircraft generation marketed itself as the “fastest and easiest way to travel”, and the “new standard in luxury”.
Indeed, the principles of speed and luxury have always been intertwined with both each other, and the concept of flying as a whole. This is why in the early 1950s, the vision was clear: the next progression in commercial air travel would be to break through the sound barrier.
Going supersonic with Concorde
France and the UK began research into supersonic commercial flight in 1954, eventually resulting, 22 years later, in Concorde. However, the lifetime of supersonic travel turned out to be short, with Concorde’s life ending after 27 years in 2003 due to changing economic factors and safety concerns.
Since then, several factors other than speed have been associated with “luxury” travel, such as quietness, efficiency and refinement, hence spelling the end of supersonic passenger travel.
Boom Overture – the next supersonic symphony
However, in 2014 an American start-up, Boom Technology Inc., envisaged a reignition of supersonic travel and set out to create a new generation of supersonic airliner: the Boom Overture.
While Boom is not the only company who has pursued this mission – indeed Exosonic, Hermeus and Spike Aerospace, among others, are all vying to compete with Boom in this space – their project has both the biggest scope and the most advanced level of development. While many of these other companies are proposing the replacement of smaller business jets with supersonic alternatives, Boom is pitching their product as a commercially viable one, more similar to Concorde.
The Overture would seat between 64 and 80 passengers depending on configuration (Concorde had between 92 and 128 seats), and as such would be focused on a “point-to-point” model of air travel. Boom says that they have identified over 600 routes on which the Overture could be profitable and benefit from reduced flight times by factors of between 33-51%, such as Honolulu to Tokyo, Zurich to Philadelphia, and Los Angeles to Tahiti.
The Overture will be able to travel at a cruising speed of Mach 1.7 (this is only possible over water, with the over-land cruising speed being just under Mach 1), at a cruising altitude of 60,000 ft and over a maximum range of 4,250 nm (7,867 km). These factors will enable the potentially revolutionary flight time reductions which Boom has proposed. One of the primary developments required to achieve these speeds is the design of Boom’s cutting edge Symphony turbofan engine, of which each Overture will have four.
Boom have partnered with highly experience and historied aerospace manufacturers for the development of Symphony, including Florida Turbine Technologies Inc. (FTT, part of Kratos Defense & Security Solutions), GE Additive (part of General Electric), and StandardAero. The primary innovations in Symphony engines include their two-spool, medium-bypass, air-cooled turbofan design, as well as its use of revolutionary manufacturing techniques such as additive manufacturing (AM). This enables lightweighting of many components, as well as reduced overall complexity and cost as a result of the higher component geometric complexity afforded by AM.
Symphony’s design is also optimized for use with 100% sustainable aviation fuel (SAF), underlining Boom’s focus on the future of supersonic travel being a highly sustainable endeavour within the context of modern ESG priorities. FTT has already started development on several dozen test units of Symphony, highlighting the advanced state of Boom’s development compared to other supersonic start-ups.
Boom have also partnered with several additional aerospace manufacturers which have aligned with Boom’s strategic priorities. Spanish aerostructure company Aernnova Aerospace S.A. has been contracted to design and build the Overture’s wing structure. The wings were designed to be especially thin in order to reduce drag, consequently enhancing both supersonic performance and transonic handling. The major structural fuselage components will be developed and manufactured by Italian aerospace and defence prime Leonardo S.p.A., who have designed a specialized narrowing fuselage which minimizes wave drag and maximizes fuel efficiency at supersonic speeds.
The landing gear will be developed by Safran Landing Systems, while Eaton will develop the hydraulic and fuel systems. Other technical partners include Aciturri Aeronáutica S.L.U. and Collins Aerospace, which have been contracted to produce many smaller systems for Overture.
But will it fly?
There is some evidence that Boom could be successful in their mission. In the last two years, American Airlines and United Airlines, two of America’s biggest, have placed orders of 20 and 15 Overture aircraft respectively, with options to order up to 75 more.
Furthermore, the U.S. Air Force (USAF) entered a three-year strategic partnership with Boom last year, valued at up to $60m. The purpose of the partnership is to accelerate research and development (R&D) on the Overture, with a view to the aircraft playing a role similar to other commercially derived aircraft in the USAF’s global logistics, where rapid transport could be a key future strategic capability.
Boom also received a contract alongside two other manufacturers (Exosonic and Hermeus) from the USAF Presidential and Executive Airlift Directorate to develop variants of the Overture specifically to transport the president and other high-ranking officials as a potential replacement for the two Boeing 747-8 aircraft currently used as Air Force One.
Doubts creeping in
However, there is some doubt concerning the viability of the Overture. The original plan was for construction of the production line to begin in 2023 after the first successful test flight of Boom’s one-third-scale supersonic demonstrator, the XB-1, in 2021. Unfortunately, while construction has recently begun, the XB-1 has still not completed a single test flight, even after the test date was pushed back first by a year to late-2022, and then another year to mid-2023.
This therefore justifies scepticism about the company’s aims for the Overture to complete its first test flight in 2026 – just three years away – before its type certification in 2029 and first passenger flight in 2030.
Further doubt was cast on the project when Rolls-Royce, manufacturers of the Olympus engines used by Concorde, pulled out of their agreement to manufacture the Overture’s engines last year, just two years after the original contract was signed.
While their replacement FTT is a subsidiary of Kratos, and therefore highly experienced in the general aerospace industry, their expertise in supersonic jet engines is limited.
In conclusion, while there is plenty to like about Boom and their mission to create a new era of sustainable supersonic flight and despite the legitimacy of their technical partners and current clients, there are still many questions Boom will have to answer before it can prove that supersonic airliners are not only back, but here to stay.