Boom Supersonic is an American startup whose goal is to return to building supersonic passenger planes, almost twenty years after the Concorde was decommissioned. On Wednesday, Boom unveiled XB-1, its first prototype, which for now is not a passenger plane: it looks more like a military fighter and can only carry the pilot. But thanks to this prototype, Boom intends to develop new technologies that, according to the company, could halve the duration of flights within a decade. Other companies, as well as NASA, are working on similar projects and it seems plausible that in a few years the supersonic jets could return to being used as airliners. However, there are still many technical, economic and environmental difficulties.
Supersonic aircraft are aircraft capable of exceeding the speed of sound. As is known, it is not the first time that someone has tried to start a commercial program using supersonic jets: Air France and British Airways did so with the Concorde, the first supersonic jet airliner, which made its first flight in 1976 but was decommissioned. in 2003. In 2000 there was a serious accident: a Concorde crashed to the ground shortly after taking off from Paris Charles de Gaulle airport and 113 people died. Three years later Air France and British Airways, also due to the reduction in the number of passengers due to the accident, assessed that the program was not economically sustainable and interrupted it.
– Read also: History of Concorde
Boom Supersonic was founded in 2014 by Blake Scholl, an aviation engineer and former manager at Amazon, where he was in charge of advertising. Scholl assembled a team of veterans from major aviation companies and raised tens of millions of dollars simply by presenting his idea to investors, even before building a prototype. To date, Boom has raised $ 200 million, and may soon announce a new round of investment. Scholl's idea, in summary, is that thanks to the technological advances of the last twenty years, not only is it possible to create a safe and economically sustainable civil supersonic jet, it is also possible to make it more accessible to the public. Scholl says a return London-New York ticket to travel on his jet will cost $ 5,000, roughly what a business-class ticket costs today. For the same route, 12,000 dollars were spent on the Concorde, which adjusted for inflation today corresponds to about 20,000 dollars.
Obviously, the main feature of the new supersonic jet would be speed: Overture should travel at Mach 2.2, that is 2,300 kilometers per hour, carrying 55 passengers (then it could become more). Boom estimates that the London-New York route, which usually takes seven hours to travel, would take three and a half hours. The Los Angeles-Sydney route would go from 15 hours to 6 hours and 45 minutes.
The technological innovations that according to Boom should allow a program of civilian supersonic jets to restart are numerous, as Bloomberg noted. The engines are much more efficient than those that were available to the Concorde designers. Additionally, the new jets will be constructed of carbon fiber rather than aluminum, which will make the aircraft lighter and easier to build.
In computer-generated images, Overture looks similar to the old Concorde, but there is a very obvious difference: in the Concorde, the front of the fuselage, pointed, was movable thanks to a complicated mechanism: during the flight it was pulled up, to make the aerodynamic jet, while during take-off and landing it was lowered, to allow the pilots to see the runway. With the new jets there is no longer a need for this mechanism: the tip always remains upwards, and the pilots maneuver with a camera system and thanks to the on-board computers.
Another important difference concerns the possibility of using software to simulate the design of the new jets instead of using the wind tunnel, as happened with the Concorde. At Bloomberg, Scholl said dozens of wind tunnel tests were done for the Concorde, each taking six months and millions of dollars.
XB-1 is an abridged version of Overture. It can only accommodate the pilot, and will initially be used for ground testing. If the ground tests go well, starting in 2021 it will be flown and this will allow the engineers to define the design of Overture. The XB-1 uses three J85-15 engines designed by General Electric to be mounted on military jets, and can run at speeds of Mach 1.3. Overture, on the other hand, will have engines designed with Rolls-Royce. According to the company's forecasts, if the prototype tests go according to plan, the Overture project could be completed within a few years. Coronavirus crisis permitting, test flights could begin in 2026 and the first commercial flights will begin in 2029.
These timelines are the first problem for Boom. At the time of founding, Scholl said it would have its jets ready for test flights by 2017, and that the first commercial passengers could fly in 2020. Boom, therefore, is about a decade behind, but according to Marco Trombetti , Italian tech entrepreneur and investor in Boom Supersonic, it is normal for these very ambitious engineering projects to be delayed: “Boom's delays worry me as much as Elon Musk's announcements,” he says, recalling how Tesla's CEO also has a long history of promises kept with years of delay, but how this has not prevented him from achieving success. Several airlines, such as Virgin Atlantic and Japan Airlines, have already placed orders for dozens of supersonic aircraft built by Boom.
Boom is not the only company active on the subject. Two other American companies, Aerion and Spike Aerospace, have plans to produce supersonic jets to carry passengers, and then there's NASA. Together with Lockheed Martin, historical military supplier, the American space agency is designing a supersonic aircraft to carry passengers, called X-59 QueSST, which should begin test flights in 2022 and has a fundamental characteristic: compared to the average of jets supersonic, it is relatively quiet.
Noise is another of the historical problems of supersonic aircraft, which having very powerful engines are noisier than normal airliners. Above all, when a jet exceeds the speed of sound it produces a huge and frightening roar, which is difficult to get used to: just a few days ago when a military fighter exceeded the speed of sound over Paris for a few minutes the citizens feared an explosion. For this reason some countries such as the United States have banned aircraft from flying at supersonic speed over their territory: this was another reason for the Concorde's failure, because it greatly reduced the possible routes. But things could change: in 2018, US President Donald Trump signed a law calling on the federal aviation authority to consider lifting the ban. Furthermore, all the startups in the sector are studying technologies to make their jets quieter.
– Read also: Would you take a flight that goes nowhere?
Supersonic flight also has other problems, of costs and environmental impact: to go so fast, a lot of fuel is consumed and polluted much more, and the issue is all the more sensitive at a time when, before the pandemic, the consequences environmental aspects of air travel were a hotly debated topic. In addition, fuel is the largest cost item for airlines, usually accounting for between 20 and 35 percent of operating costs.
A 2018 study by the International Council on Clean Transportation (ICCT), a nonprofit, argues that a supersonic jet could burn between five and seven times more fuel than an airliner. On a flight between London and New York, fuel consumption would be around 600 kg per passenger, double the consumption for a normal business class passenger and between six and eight times the consumption for a normal economy class passenger. This means that a return flight between San Francisco and Tokyo would cost $ 1,400 per passenger of fuel alone, compared to $ 360 for business passengers on regular scheduled flights. Furthermore, the ICCT estimates that CO2 emissions would increase by 70 percent and nitrogen monoxide emissions by 40 percent.
Supersonic flight companies believe this data is incorrect and ensure that new technologies in engines and fuel blends make fuel economy more efficient and sustainable. Boom promised last year that its XB-1 tests will be carbon neutral (it's not clear how this can happen, though) and that Overture's supersonic program will be ecologically sustainable.
