Re: PLAAF new JH-XX / H-X bomber soncepts
Furthermore, the one image we have of the potential flying wing indicates four engines. If each of those is a WS-10, we could be looking at something with a mtow that is far above 100 tons.
I think an 80 ton MTOW for H-18 is realistic.
But your'e right, a 4 WS-10 flying wing will definitely be well over 100 tons and be in B-2 territory.
---
I think you might be underestimating the weight classes of these potential bombers. What we're seeing, if both these bombers materialize, is the PLAAF's attempts to completely transform what their force composition looks like and drastically expand what they're capable of. Personally, I'm still skeptical about China developing both a flying wing and a supersonic bomber, because that would almost categorically necessitate that one be a significant weight and range class above the other, and that doesn't quite fit with where I think China's security interests and needs would extend to within the next decade. We'll see.
If we look at the PLA's future air force without the lens of a US style force structure, I think H-18 and H-20 both make a lot of sense.
One of the limitations of small/medium sized stealth fighters is their short range, for they must rely wholly on internal fuel and payload to retain their VLO. Just look at F-22 and F-35. That is why CAC has gone for J-20 with a much greater internal volume. They know that the missions PLAAF wants to fight in future will require long range and high endurance.
In that sense, one has to wonder whether the PLAAF needs an F-35 sized stealth fighter, when future 4+ fighters like J-10B/C and new flanker variants can do the job of short/medium range A2A combat just as well, especially if integrated into a wider AEWC network and with frontline J-20 support.
The best site to fight an enemy aircraft is when they're on the ground. Therefore I propose that the PLAAF may reject procuring large numbers of J-21 akin to USAF procuring of F-35, and instead use that cash to buy more J-10B/C, J-16/J-11D (which would probably all be magnitudes cheaper), as well as H-18 and H-20, and also larger numbers of J-20.
If both J-20 and J-21 are acquired by the PLAAF, they will probably end up with similar J-20 numbers to USAF -- so not that high. If they can reject the many hundreds of J-21, and settle for a non-stealth aircraft, they can instead use the savings to produce more long range J-20s, H-18s and H-20s.
With its long endurance, J-20 can conduct air superiority missions well beyond the first island chain. H-18 may indeed be capable of carrying long range interception as well, if equipped with AAM and a large radar. Both H-18 and H-20 will be able to hit airbases where US "short range" F-35 and F-22s are based, as well as striking at bases where they could station air refuellers. Without aerial refuelling, USAF F-35s and F-22s become far less of a threat, and indeed USN carrier based aircraft will be hard pressed to strike at mainland targets as well (all long range CVN sorties currently require USAF tanking, and this won't change in the future given F-35 is such a small plane).
Sure, J-10B/C, J-16 etc will be challenged by regional air forces with their own F-35s or stealth fighters. But with a continuing modern IADS on the mainland, as well as the short range of F-35, Japanese F3 and KFX, all potential opposing stealth fighters will be hard pressed to make a dent into the PLA's vast strategic depth. If anything, PLAAF 4+ generation fighters, supported by a massive PLA AEWC network, along with a small number of high end J-20s in frontline support, could probably contest the skies well into the first island chain -- and that's assuming H-18s, H-20s do not strike at airfields first, and assuming the lion's share of J-20s are not engaged.
So ultimately the H-18/H-20 will provide PLAAF a capability they have in some degree at present -- the ability to strike at regional targets with precision and high degree of success. Today that is accomplished by mostly IRBMs and LACMs. In future, that force will likely grow, but will also be supplemented by more flexible and harder to detect stealth bombers with their own stand off LACMs.
It would be a bold decision to make to deviate from a proven "high, low" fighter fleet (F-15/F-16, F-22/F-35, Su-27/Mig-29 etc) of past decades, to a "high, high, superlow" fighter/bomber fleet (J-20, H-18/H-20, J-10B/C/J-16), but I believe it would be the most beneficial one for PLAAF. At cursory glance, a PLAAF of the mid 30s should aim for:
400 J-20s
100+ H-18s
40 H-20s
120+ (?) legacy H-6Ks
800-1000 J-10 and flanker variants
All supported by a high number of AEWC, tankers, and ELINT aircraft.
Otherwise they will have to give up much of their J-20s, H-18s and H-20s for a lower end stealth fighter like J-21, which simply wont' have the range and endurance to be where it needs to be.
