S U P E R SO N I C Supersonic summer Can society learn to stop worrying and love the boom? By Captain Robin Evans, Senior Log Contributor C oncorde famously overcame technical hurdles to circumvent economic ones. Though the supersonic airliner has been silent for two decades, humankind never stays still for long, and a steady push back to Mach 1 is about to start bearing visible, if less audible, fruit in the nation that objected the most. The US has a complicated sociopolitical history with sonic booms and, without its own design, was unlikely to permit its carriers to operate a rival, though it did come to grudgingly value Concorde on specific routes. Now, the US supersonic overflight ban of April 1973 is being reconsidered, with NASAs X-59 sonic-boom suppressor unveiled in January. Then, airborne in March, came Boom Supersonics XB-1, the demonstrator for its Overture supersonic airliner. Both use the latest technology for a revisionist approach to these historic, acoustic and economic hurdles. NASAs technical challenge has been to design a body and wing that avoids a strong, double shockwave at ground level, enabled by computational fluid dynamics (CFD) and modern acoustic understanding. Booms challenge is to secure a market, mitigating all the previous objections, in entirely different times. More than 75 years since the sound barrier was broken, how and why have these independent efforts come about to fix it? Humane factors Time magazine of May 1965 wrote: When those who were uncertain about the advisability of supersonic planes were reminded that the French, British and Russians were already working on them, eight out of 10 patriotically agreed the US should proceed with an SST [supersonic transport] of its own. Boeing reached high: initially a swingwing, their 2707 was a Mach 3, 250-seater. Time magazine speculated: It may some day be possible to design supersonic aircraft so that their booms will be less annoying and damaging, but this is by no means certain. The FAA summed up by urging more study an amber rather than green light to the supersonic age. Operation Bongo was the controversial benchmark study of population response to sonic booms in St Louis (1961) and 26 THE LOG Sum 24 pp26-31 Supersonic.indd 26 13/06/2024 12:43