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SR-72: US secret hypersonic jet to allegedly break sound barrier in 2025
(interestingengineering.com)
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this post was submitted on 04 Jan 2024
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Futurology
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These speeds have an actual use for the military. Since they are faster and fly higher than anything else in the sky, it is really hard to get a missile to intercept these birds. Hence, they can fly over interesting locations, take pictures, and scedattle.
Maybe even drop a payload. Which effectively turns them into reusable ICBMs.
Oh I know, but the point I'm making is that things higher up go faster. The space station orbits the Earth in 92.9 minutes. Also, using mach numbers doesn't really tell you anything without an altitude or pressure. Mach 1 at ground level is faster than mach 1 at 60,000 feet.
The military is accutely aware of this, just look at the U-2 spy plane. That thing flies so high that the speed of sound is so low and the stall speed so high that they're nearly the same - this is referred to as "coffin corner" of the flight envelope. Pilots have to be exceptionally careful banking at this altitude, as the inner wing will go slower than the outer wing in a turn, so you can have the tip of one wing stalling and the tip of the other wing breaking the speed of sound.