[ballooney]

I think the GP might have meant that Mach 3 at ground level is even more technically astonishing - a lot of the historial benchmarks for airspeed (mach 2 fighters and interceptors, the SR71's mach 3) were only valid at very high altitudes were the atmosphere is sufficiently thin to make the achivement teneable from a drag and heat-flux perspective. To cruise along at Mach 3 at sea level is a quite astonishing display of brute force.

[lupusreal]

I'm skeptical of such a capability. Even granting the engines the power and durability to do that, what about the rest of the airframe and avionics? How do they prevent those from being baked if not outright melted? The SR-71 required a substantial engineering effort to withstand the shock heating at that speed but the SR-71 flew very high in thinned air.