Bring supersonic travel to skies all over the world and make it accessible to the broader public, but also sustainable on an economical and environmental level, redefining the commercial aviation market. This is the objective of Boom Supersonic, an American start-up that plans to take the vacant place left by Concorde after its final flight in 2003. “Overture” is the name of the supersonic jet that the company plans to build in 2023, after successful testing of the XB-1prototypes that are scheduled to take off on their first experimental flight beyond the sound barrier from the Mojave spaceport in California at the end of this year. According to the schedule, Overture should then be completed by 2025, with the first passenger flight forecast for 2029.
The Denver-based company’s pledge is a futuristic one: “Reach anywhere in the world within four hours at a cost of just 100 dollars”, states CEO Blake Scholl in an interview with CNN, in which he describes a scenario that can only come to light thanks to the upcoming technological advances over the arc of two or three generations of aircraft, i.e. one or two decades. According to the same CEO’s past statement, initially, tickets should cost around 5.000 dollars. In the 90s, the price to board a Concorde rose to up to 12,000 dollars, which in today’s money is the equivalent of 20.000 dollars.
A technological masterpiece of the 1960s, the Anglo-French aircraft could reach a cruise speed of ‘Mach 2.02, but it was only used by British Airways and Air France. The aircraft was extremely expensive to run and maintain and these issues continued to be unresolved until its very last flight in 2003. The plane’s only competitor was the Soviet’s Tupolev, which remained in service for approximately twenty years, but only ever transported passengers with Aeroflot for six months, between 1977 and 1978. Able to reach a speed of up to 2.35 Mach, it is still the fastest non-military plane in history even today.
In terms of the Overture, the aircraft can reach a speed of 1.7 Mach, covering 2.000 kilometres (1243 miles) per hour. That’s double the velocity of a Boeing 787, which can reach a subsonic cruise speed of 0.85 Mach, covering just over a thousand kilometres (621 miles) an hour. Flying at an altitude of up to 18.2 kilometres (11.3 miles), a similar performance would halve the time currently necessary to serve the 500 transoceanic routes that Boom intends to cover. Crossing the Atlantic, the supersonic jets will be able to connect New York and London, or Madrid and Boston, in just three and a half hours. Whereas, flying over the Pacific, it would take just four and a half hours to get from Tokyo to Seattle, or eight and a half from Sydney to Los Angeles. With a length of 64.5 metres, Overture will be able to transport 65-88 passengers (its predecessor could carry up to 128), seated in two single files, and carry out direct flights thanks to a flight range of approximately 7.800 kilometres (4888 miles).
Running costs will be 75% lower than those of the Concorde, explains Scholl, but as well as the challenge of economic sustainability, there is also the issue of the environment, which Boom hopes to achieve with a 100% zero-emission aircraft. With the target of consuming the same amount of fuel as a subsonic business class flight, the first tests were carried out on XB-1 engines in January 2019, using a mix of 80% Sustainable Aviation Fuel (SAF) made from animal fat.
Five months later, the company signed a deal for a collaboration with the Prometheus Fuels start-up, a project that converts the CO2 in the atmosphere into liquid fuel that has the same molecular make-up as fossil fuel. Powered by clean, renewable energy sources, the technology relies on electrochemical and catalytic processes. The sustainable turbofan propulsion system will be designed by Rolls-Royce, the same company that supplied the Olympus 593 turbojet used on the Concorde.
The XB-1prototype was specifically designed to test out the many other technical specifications that will also need to be applied on the Overture, both on a reduced 1:3 scale and with different types of engine, given that the aircraft will be using three General Electric J85-15 turbojets. Modern developments in materials have allowed for the replacement of the aluminium of fifty years ago with a carbon fibre composite material, which will help eliminate aerodynamic disturbances and reduce sonic boom (the aircraft will only be able to exceed the sound barrier when crossing the oceans) and provide better heat resistance, as temperatures can reach up to 125° C at extremely high altitudes. The delta wing system that stabilises the aircraft will be similar to the one that made the Concorde so famous, but Boom has shelved the idea of a droop-nose, adopting a remote vision system that uses a frontally installed video camera to widen the pilot’s visual, which is significantly obstructed by the long nose.
“Physics does not permit the construction of an ugly supersonic aircraft”, remarked Scholl, adding, however, that “We’ll either fail or we’ll change the world”. The development costs to arrive at Overture’s maiden flight could reach 8-billion dollars, with each individual aircraft costing 200 million. The project will be assessed by the American Federal Aviation Administration (FAA), and has already aroused the interest of investors, partners and potential clients. Established in 2014, to date, the company has received 250 million dollars in funds, already reached ‘unicorn’ status with valuations of over a billion, and currently employs 150 people. And several flight operators are already knocking on Scholl’s door.
The latest company to want its name on the first Overture passenger flight in 2029 was United Airlines. In fact, in June, the American airline has already signed a 3-billion-dollar contract for fifteen aircraft and also taken options for a further thirty-five planes.
This will be Booms first cash payment, even though the company already has preorders amounting to 6 billion, including an order from Japan Airlines for twenty aircraft and an order of ten vehicles from Richard Branson’s Virgin group.
According to a report by the UBS financial services company, the global supersonic flight market will be worth 160 billion dollars by 2040 and, Boom Supersonic is not the only company to want a slice of the action. For example, the same Virgin Galactic is currently working on a supersonic Mach 3 tourist aircraft in collaboration with NASA, which could take passengers from London to New York in just two hours. In this case also, according to a contract signed in 2020, Rolls-Royce will be supplying the engines,.
In turn, in 2018, the American space agency awarded a 247-million-dollar tender to Lockheed to design, build and test the X-59, a silent, supersonic aircraft that should reduce sonic boom to a sound similar to someone closing a car door. The first tests are planned to be held in 2022. Meanwhile, Spike Aerospace is working on a Mach 1.6, 18-seater aircraft; the Russian aviation consortium, the United Aircraft Corporation, has joined forces with a foundation supported by the Arab Emirates to develop a project, and the Japanese space agency is toying with the idea of a 5 Mach supersonic jet that can carry 30-50 passengers.
But the runway to the supersonic challenge is still littered with obstacles. In fact, Aerion Supersonic, which has been operating since 2003, caused uproar in May when it suddenly announced that it was closing due to trouble raising the capital to get from the planning to the production phase of their first AS2 jet, with development costs amounting to 4 billion dollars. The aircraft was supposed to carry a dozen passengers and had already gained widespread interest, with a good 11 billion dollars-worth of pre-orders. Aerion had even patented a system that would eliminate the so-called ‘sonic boom’ and was also developing a Mach 4 craft that could carry 50 passengers. However, without finance, supersonic travel will not get off the ground.