3 ms·
No. A lot of hypersonic stuff is partly classified. So the journalists are left with the definition: hypersonic speed is Mach 5 and higher. Mach 5 is where the
by credit_guy 3y ago
No. A lot of hypersonic stuff is partly classified. So the journalists are left with the definition: hypersonic speed is Mach 5 and higher. Mach 5 is where the heat produced in the boundary layer (by compression, mainly) is high enough that chemical reactions take place and you need to account for them in your computational fluid dynamics.
As a rule of thumb, when you hear boost-glide vehicle, the speed is close to Mach 20. If it’s air breathing (ramjet or scramjet) the speed is slightly higher than Mach 5, but probably less than Mach 10.