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An Anonymous Coward writes:
The BBC writes about a hypersonic plane concept patented by Airbus. With the mix of engine types, comparatively exotic fuel, it sounds like those tickets might get really expensive. We'll see if this ever flies, and if so, whether it will be a commercial success, unlike the supersonic Concorde. On the military end, things might be of more interest...
According to the documents, the jet would reach speeds as high as Mach 4.5, or four-and-a-half times the speed of sound. That compares to Mach 2 for Concorde.
The patent application says that the aeroplane would use a variety of engines that would serve different purposes and power would come from hydrogen stored onboard.
Two turbojets under the fuselage and a rocket motor in the rear would be used during take-off. It would lift off vertically like a Space Shuttle. Once launched, the turbojets would be shut down and retracted and the rocket motor would then kick in to climb to an altitude of more than 100,000 feet. Then ramjets, more usually used on missiles, would be ignited and the flight would reach a top speed of Mach 4.5.
(Score: 0) by Anonymous Coward on Thursday August 06 2015, @05:50PM
OK so take a look at this article [sengpielaudio.com]. Pressure from sonic boom degrades at 1/r not 1/r^2. Since car alarms work off pressure, I bet you could still set off a decent amount even at 30 km altitude, especially since the aircraft is still accelerating at that point, mostly pointed up (sonic boom pointed downward). I haven't done the math (doubt I could tbh) but who knows.