United Airlines is first on the runway, hoping to become the fastest airline in the world-a supersonic airline. United ordered 15 jets from Boom Supersonic, which claims its “Overture” aircraft will be able cut flight times nearly in half. Think of Newark to London in just three and a half hours. How about traveling from San Francisco to Tokyo in only six hours.
THE RETURN OF SUPERSONIC?
Does this all sound familiar? That’s because it is. We had nearly two decades of supersonic travel, if you could afford a ticket on the Concorde, starting in the 1980s. The British-French jet provided flights which broke the sound barrier (traveling faster than Mach 1) until it was retired in 2003-a victim cost of operation and noise issues.
There has been a push since then to improve the technology, reduce sonic booms, pollution, and cost of operation. There are plenty of players and hurdles to overcome before we return to supersonic travel. But it is coming?
United is making a big bet. In addition to the 15 aircraft now on order, it has an option to purchase 35, more making a fleet of 50 carrying 65-88 passengers at a speed of up to 1.7 Mach. But, and this was a big selling point for United, the Overture is net-zero carbon. That’s because it will use what is called “100% sustainable aviation fuel.” SAF, as it is known, is not just bio-jet fuel from plants and animals. It can also be made from sustainable “non-biological resources.” It’s being used today, but it is not available in the quantities airlines will need. In their June 3, 2021 announcement United and Boom said they will work together to “accelerate production of greater supplies of SAF.”
United’s CEO Scott Kirby, who wants to make his airline more sustainable, highlighted that the changes in fuel and aircraft design are bringing about this re-birth of supersonic travel. Kirby says, “today’s advancements in technology are making it more viable for that to include supersonic planes. Boom’s vision for the future of commercial aviation, combined with the industry’s most robust route network in the world, will give business and leisure travelers access to a stellar flight experience.” The founder of Denver based Boom Supersonic, Blake Scholl, says this is about making the world more accessible. “At speeds twice as fast, United passengers will experience all the advantages of life lived in person, from deeper, more productive business relationships to longer, more relaxing vacations to far-off destinations,” Scholl said.
Sounds great, but you will have to wait a bit. The new technology hasn’t been proven in flight yet Boom hasn’t flown its test aircraft the XB1, and the “Overture” hasn’t been built. Boom says the “Overture” will be rolled out of a hangar in 2025. Its first flight is set for 2026. Passengers, if all goes as planned, will board in 2029.
Boom Supersonic is now one of the few players in supersonic transport (SST). Just a few weeks before this announcement, Aerion Supersonic of Reno, Nevada, suddenly shutdown its efforts to build a smaller supersonic business jet. Aerion was working on the “AS2” aircraft carrying 8-10 passengers. Aerion said a funding round failed to raise the necessary capital. The company had a big backer in Boeing.
Boeing is not unfamiliar with supersonic travel. In 1971 it gave up on its SST, the Super Sonic Transport jet. Funding was pulled, after nearly two decades of research, design, and prototype work on the 318 foot long aircraft which was expected to travel at Mach 2.7. In the early 2000’s Boeing pitched the “Sonic Cruiser” to airlines. It would have traveled just under the speed of sound. Airlines weren’t buying it, and Boeing moved on to produce the 787.
YOU CAN BUILD IT-WILL THEY CERTIFY IT?
Boom’s jet and any new players face a major obstacle; those sonic boom that supersonic jets produce. The new SST’s might be certified to fly over oceans. But United and other potential customers would undoubtedly like to use supersonic transport for trans-continental flights as well. The problem; there are noise restrictions for aircraft over land. The Federal Aviation Administration says existing rules prohibit “…a true flight Mach number greater than 1 over land in the United States and from a certain distance off shore [sic] where a boom could reach U.S. shores.” So, there’s a desire to go supersonic, but the boom is the limiting factor.
So how is the boom problem solved? By quieting the shattering of the sound barrier. There is a push by both the government and industry to figure out how to make a new SST a reality. The FAA says it is taking steps “to advance the development of civil supersonic aircraft,” and that Congress has directed the FAA and its Admnistrator to “exercise leadership” to certify the “safe and efficient operation of civil supersonic aircraft.”
However, the FAA is making it clear to jet makers exactly what must happen before they can test their aircraft. The agency recently posted a new proposed rule. Boom submitted a comment that suggested the company is so confident its planned jet would be quiet that the “FAA would be unlikely to identify any significant sonic boom noise impacts for individual supersonic flight test programs…” The FAA did not agree with Boom’s characterization.
That may just be some squabbling. The U.S. government is trying to help industry re-enter supersonic travel. As mentioned, Congress has told the FAA administrator to show leadership. And NASA is working to give data to the FAA that will allow it to set the rules for this fast aircraft.
NASA RESEARCH-THE QUIET BOOM
NASA calls it QueSST; Quiet Supersonic Technology. NASA is hoping to prove that design changes can “quiet the boom.” It’s building a demonstration aircraft the X-59. Like Boom, NASA’s aircraft has not flown yet. The problem for researchers is that at the speed of sound a jet is moving so fast it is slamming into air molecules which cant’s be pushed aside quickly enough and that sonic boom is the result. By changing the design of supersonic aircraft (longer nose with addition of canards- winglets), the hope is to “quiet the boom.” The X-59 hasn’t flown yet either. It is more than half built. No aircraft has yet proven its technology. So, certification of a brand new aircraft is not a certainty. All the simulations suggest this will work, but let’s see when an aircraft takes to the skies.
A quarter century after the Concorde disappeared, Supersonic Transport could be coming back at the end of the decade. But how much will a ticket cost?