In the 1960s anyone giving much thought to the future of commercial air travel would probably have told you that by 2017 every flight you’d take would be in a jet capable of flying supersonically – faster than the speed of sound. Today you don’t have to look at an airline timetable for too long to see that flight times don’t reflect a supersonic journey.
While Concorde was the first commercial jet to break the sound barrier in the 1970s, the promise of a supersonic future eventually faded. High fuel costs, sagging margins and sonic booms – the ear-shattering shockwave that comes from a jet at supersonic speeds – made for a turbulent flight path. Concorde flew for nearly 30 years, but it never became the standard that many assumed it would.
Supersonic travel today
Now, lighter materials and enhanced flight technologies mean that once-dormant supersonic initiatives are again taking flight. Of particular note is Denver, Colorado-based Boom Supersonic. In late-March the privately held startup announced that it had just closed a $33-million round of fundraising for the test-flight phase of its XB-1 programme. This marked a new era as a government agency wasn’t leading the charge on commercial supersonic flight. It seems the seventies could be back. And very soon.
Beyond the revival of a mid-century jet-set mentality, proponents of supersonic travel hope new technologies will mean better margins. Virgin Galactic’s Sir Richard Branson has so much faith in the forthcoming XB-1 Boom jets that he has doubled down, placing the first orders for the aircraft type. “Virgin Galactic’s decision to work with Boom was an easy one. We’re excited to have an option on Boom’s first ten airframes,” Sir Richard said in late-2016. Risks have rarely deterred the billionaire entrepreneur – Virgin logos on the tails of the first Boom jet fleet would be par for the course.
Still, the subject of noise is conspicuously missing from much of the information that Boom has put forth regarding the XB-1 jet. The startup’s bid to go supersonic has less to do with noise reduction and more to do with reviving the high-speed, intercontinental premium experience that Concorde used to offer. The company maintains the XB-1 will make a “much quieter ‘boom’ than Concorde”, yet cruise 10 per cent faster at 1,451mph.
Peter Coen, supersonic programmes manager at Nasa, says the venture projects are a, perhaps noisier, tranche of the fast re-emerging drive for commercial supersonic flight. “That’s one disconnect between what Nasa’s doing and what the venture capital folks are doing,” he says. “They’re looking to get into the market immediately with minimum technology and we’re looking at growing the market and the technology simultaneously so a larger market can be served in a more environmentally compatible or friendly fashion.”
Regulators have the last word with laws on the books that prohibit supersonic flight over many of the world’s populated areas. Anything beyond trans-oceanic travel, where the shocking and eardrum-bursting sonic booms produced by these jets won’t bother anyone, is out of the question.
According to Mr Coen, Nasa’s vision consists largely of a world where supersonic flight becomes standard over open ocean and land. But for that to happen, regulations must change or supersonic jets must get quieter. US Federal Aviation Administration law stipulates operators must “ensure that flights entering or leaving the United States will not cause a sonic boom to reach the surface within the US”. In short, airlines couldn’t use the Boom jets to fly supersonically overland between New York and Los Angeles. The laws aren’t much different in Europe. This, for now, means supersonic flight options would be the thing of intercontinental travel and not much else.
International aviation authorities, both governmental and non-governmental, are working to define what supersonic regulations might look like in the coming era, but the onus is on engineers to prove any new technologies make more of a gentle thump and less of a shocking boom