What the... So China is really working on a Mach 4 manned combat aircraft!? Not long ago we were discussing about an air launched missile with M=4, H=23km launch parameters.
Would you be surprised that China's working on mach 5+ manned aircraft?
Why else has China been developing and test flying so many combined cycle engines, scramjets and detonation engine aircraft? Not just missiles, for reusable aircraft. They didn't even make it too much of a secret since you know, the US watches each flight closely with space and sea based monitoring. It's partly why the US is on record on multiple occasions saying that they've watched "many hundreds" of Chinese hypersonic test flights over the last two decades. It's why they say China's hypersonic aircraft and missile programs and far ahead of the US.
Three pillars of hypersonic manned aircraft; materials (this parts easy and pretty much mastered, just a matter of pushing and optimising even further), engines (China's flown TRCC, RBCC, rotating detonation engines and oblique detonation engines for many years), hypersonic flight control (HGVs and HCMs are stepping stones to scaling this to manned aircraft).
Question is what can you do with high supersonic/ hypersonic manned aircraft that you can't do with ballistic missiles, HCMs combined with stealth strike aircraft with much more range and payload. Nothing useful that's worth the extra effort. My guess as to why China's pouring in so much material and energy into this is because the first few generations may not be worth much compared to existing alternative platforms but this technology branch is certainly worth pursuing and what better time to start making an effort than the very moment when you realise something is worthwhile.
