Why a Mach 5 passenger plane is a crazy idea that might just work

Almost two decades since Concorde retired, interest around supersonic travel has been picking up pace, and several super-fast planes are under development. Airlines seem interested: United has already committed itself to offering supersonic routes as early as 2029. But what about hypersonic travel, which happens at speeds of Mach 5 -- five times the speed of sound -- and above? That would get an aircraft from New York to London in just 90 minutes, compared to about three hours for Concorde, and between six to seven hours for a regular passenger jet. Is it even possible? Hermeus, an Atlanta-based startup whose goal is to develop hypersonic aircraft, believes so. It's already testing a new type of engine it says will eventually be capable of reaching Mach 5 (over 3,000 mph). The engine is designed for a small, unmanned hypersonic aircraft Hermeus is currently creating for the US Air Force, but scaled to a bigger size, it will be able to power a passenger plane. That passenger plane is a long way away -- Hermeus hopes to get it in the air for the first test flight before the decade is out, in 2029 -- but because its technology has to be built almost entirely from the ground up, the company is already planning it out. For a start, it will be much smaller than current airliners and even Concorde, which had a capacity of around 100 passengers. Story has more.<br/>