Chinese SST.
 

This seems to have slipped under the radar.
I searched through Pprune but couldn't find any reference to it. Anyone know any more?

https://www.globaltimes.cn/page/2025...ering%20phase.

First I'd seen of it, interesting.

Worth mentioning that M=4+ you're out of supersonics, and into hypersonics, where the behaviour of air, which is becoming ionized, becomes increasingly driven by the plasma chemistry. There's a whole new set of laws of aerodynamics to learn there, which few people even begin to understand yet.

I somehow doubt that its primary role is civil air transport.

G

At M4+ you are into X-15 territory for the aero-thermodynamics, heat resistant materials and hot structures. Concordes M2 cruise was very much temperature limit for aluminium structure. The raison d'etre for X-15 was to determine which aero theory gave the best correlation to measured values.