Originally Posted by
Jhieminga
I'm also surprised that they want to aim for Mach 3. History shows that using a conventional structure is easier to produce and operate, and that leaves you at Mach 2 and a bit (127 deg C on the nose was Concorde's hard limit). Can you go faster using composites? We're into relatively unknown territory there as this is not a quick dash to high speed, but sustained flight for several hours at that speed. The only type that has done that before was built using lots of titanium.
Around Mach 3 is the sweet spot for Ramjet efficiency, so I suspect that's what they're shooting for. As for materials, you can get pretty high temps with the proper composites (and I suspect most - if not all - all new aircraft are going to made of mostly composites).
But I still don't see how they can get reasonable fuel efficiency going Mach 3 compared to today's ~0.8. So a niche market where time is more valuable than money...