THE last commercial supersonic flight was BA002, from New York to London, on October 24th 2003. Blake Scholl, boss of Boom Supersonic, in Denver, hopes people will not have to wait another two decades for the next. Boom’s putative Concorde replacement, Overture, which is intended to carry 64-80 passengers (Concorde carried 100), has not yet been built. But on January 28th XB-1, a one-third-scale demonstrator that the firm is using to test its airframe technology, broke the sound barrier for the first time.
This 34-minute flight, the culmination of 11 previous subsonic ones, took off from Mojave Air and Space Port in California. Its three faster-than-sound legs, maxing out at Mach 1.11, happened in the Bell X-1 Supersonic Corridor—a piece of airspace, designated for such high-speed activities, between Mojave, a civilian facility, and Edwards Air Force Base, one of America’s main centres for testing military aircraft. It was also the XB-1’s penultimate outing. The plan is to fly it once more, next week, and then retire it to concentrate on building Overture.
There is still a way to go, though, before passengers can check in. Not only must lessons learned from XB-1 be transferred to Overture’s larger airframe, but Boom has also to produce engines to match. The demonstrator is powered by a trio of General Electric’s J85-15 engines, previously installed in a Canadian fighter aircraft. The main event will have four so-called Symphony engines. These are being developed in-house and from scratch after the dissolution, in 2022, of a partnership with Rolls-Royce.
Mr Scholl reckons a Symphony prototype will be available for ground testing by the end of the year, and a version with all the wrinkles ironed out should be ready, by 2028, to be matched with the Overture airframe in Boom’s factory in North Carolina—thus permitting a maiden flight that year. On this schedule, commercial flights would start in 2029.
There is certainly commercial interest. According to Mr Scholl, the order book stands currently at 130. He sees the relationship between Concorde and Overture as mirroring that between the Apollo project and the rockets created by SpaceX. Both Concorde and Apollo, though technological successes, were built for reasons of national pride. When politics moved on, they became redundant. Elon Musk’s offerings were designed from the get-go to make money. Mr Scholl has similar plans for Overture.
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