“The big problem now is not with the technologies, but material sciences. Heat being the biggest antagonist.
Avoiding disintegration is the obstacle.”
I was a designer on enabling technologies (mach 25) for the NASP. That was my very first hypersonic project. What a great little team we were. We were successful. Withstanding 3000 degrees f and the shock of hypersonic flight for hours on end was accomplished. That’s why I say we should already be there.
Simulated, or real?
I saw a Ramjet Motor at Rocketdyne and, to me, it looked too simple to work. I was assured it does.
It was all about materials and very, very precise shape and surface.
But I haven't a clue what was inside where I could not see.
I just know if they get it, all of it, working together people are going to be wowed.
That said, considering the stresses and heat involved I expect a great deal of maintenance between flights.