H-20 bomber (with H-X, JH-XX)

[Blitzo]

It all comes back to this. Engines.

While China's caught up very quickly in aircraft engines of all types, particularly military ones, it still lags the US slightly to perhaps up to a decade.

US and China are both flying fuel combusting engines derived from last century. Combustion reaction engines will always be the primary limit to what we can do in aviation and there's no sight of anything revolutionary. People talk about flying saucers, anti-gravity this that and whatnot but if they existed, the world would undergo an industrial revolution we've never seen. Variable cycle engines will give these next generation aircraft a bit more push overall and a lot more efficiency - range. H-20 would have been designed around WS-15 I or II and intended for next gen engines like J-36. Even if it has the push and shape to go supersonic, it wouldn't be able to lob those heavy ALBMs we see strapped to H-6s. If there's a long and non-stealthy bomber that is designed to go supersonic and lob these large ALBMs strapped externally, it sure wouldnt be anywhere near stealthy. They can make it LO with effort but these two roles are so distinct.

There is no particular reason why a H-20 designed around stealth, range, and internal carriage of large hypersonic weapons, would need to be supersonic capable.

In fact I'm not even sure why the notion of supersonic performance for this aircraft is being touted at all.... and when the need for supersonic performance is omitted, the engine situation also becomes a fair bit simpler as well (variable cycle loses much of its attractiveness)

Wouldn't an air launched YJ-20 approach a maximum range of 2000km, and be able to be carried in an IWB of under 10m length?

Air launched YJ-20 is optimized for UVLS naval launch. It has certain fixed limitations on its payload size, onboard ECCM etc. Being a biconical hypersonic/aeroballistic weapon it also is not a hypersonic waverider glider or a hypersonic cruise missile.

We are talking about a high ender/larger air launched weapon. A more capable warhead, onborad ECCM etc are all a given.

 

[FriedRiceNSpice]

Air launched YJ-20 is optimized for UVLS naval launch. It has certain fixed limitations on its payload size, onboard ECCM etc. Being a biconical hypersonic/aeroballistic weapon it also is not a hypersonic waverider glider or a hypersonic cruise missile.

A hypersonic cruise missile of equivalent range would definitely be larger than a HGV of equivalent range, but wouldn't a waveriding vehicle have a superior gliding range to a biconical vehicle?

 

[Tomboy]

To be honest, a modified, but enlarged planform that is like J-36 or X-47A in geometry could be somewhat viable for the aircraft we are thinking. And it could be only subsonic; adopting such a planform doesn't mean it will need to be supersonic capable at all.

Thing with that planform is that it'll have worse RCS than B-21's planform, actually from this study, it's quite a bit worse overall although B-21's planform has higher spike at the one angle where everything is aligned to. Which is why I think cranked arrow design should be ruled out for an ELO/ULO strategic bomber.

 

[Blitzo]

A hypersonic cruise missile of equivalent range would definitely be larger than a HGV of equivalent range, but wouldn't a waveriding vehicle have a superior gliding range to a biconical vehicle?

I don't see how that relates to what I've written.

The key point isn't about whether the air launched hypersonic is biconical, glide or HCM, rather it is about how any UVLS sized weapon will be less capable than the air launched weapon we are talking about due to it being smaller (sized for UVLS)

 

[ougoah]

There is no particular reason why a H-20 designed around stealth, range, and internal carriage of large hypersonic weapons, would need to be supersonic capable.

And I'm saying it couldn't be made supersonic. You can't have an aircraft that is stealth, strategic ranged, has the internal carry capacity of large ALBMs like YJ-21 and also be supersonic. But it isn't accurate to say there isn't any value in a non-stealthy, long ranged, high capacity supersonic aircraft that can lob YJ-21s. You made a case for survivability and the need for stealth being greater than the need for speed for these aircraft mission profiles. I'm inclined to agree. The stealth H-20 is far more important than a non-stealth but supersonic H-20 that does everything else exactly the same.

In fact I'm not even sure why the notion of supersonic performance for this aircraft is being touted at all.... and when the need for supersonic performance is omitted, the engine situation also becomes a fair bit simpler as well (variable cycle loses much of its attractiveness)

This forum has discussed this endlessly (and I've contributed to those conversations). It probably comes from the whole Tu-22M purchase fiasco paraded by Russian propaganda during the early Syria years. Then the conversation on H-20 introduced this supersonic idea when it kept getting delayed and rumours of entire redesigns were brought up or invented.

 

[Blitzo]

View attachment 158947
Thing with that planform is that it'll have worse RCS than B-21's planform, actually from this study, it's quite a bit worse overall although B-21's planform has higher spike at the one angle where everything is aligned to. Which is why I think cranked arrow design should be ruled out for an ELO/ULO strategic bomber.

Uhhh the planform I described is nothing like any of the flying wing configurations above.
When I say an evolved J-36 or X-47A planform, this is what I'm thinking about:





Furthermore, even if hypothetically the RCS of such an aircraft was "worse" than a B-21.... who cares? The H-20 would have a different role not to mention a vastly different size.

Unless of course meeting the RCS of B-21 is viewed as a design requirement, in which case that is just a design and engineering question and is eminently solvable because as I wrote previously, a H-20 designed around weapons bay length would not be a B-2 or B-21 or WZ-X style flying wing to begin with.

And I'm saying it couldn't be made supersonic. You can't have an aircraft that is stealth, strategic ranged, has the internal carry capacity of large ALBMs like YJ-21 and also be supersonic. But it isn't accurate to say there isn't any value in a non-stealthy, long ranged, high capacity supersonic aircraft that can lob YJ-21s. You made a case for survivability and the need for stealth being greater than the need for speed for these aircraft mission profiles. I'm inclined to agree. The stealth H-20 is far more important than a non-stealth but supersonic H-20 that does everything else exactly the same.


This forum has discussed this endlessly (and I've contributed to those conversations). It probably comes from the whole Tu-22M purchase fiasco paraded by Russian propaganda during the early Syria years. Then the conversation on H-20 introduced this supersonic idea when it kept getting delayed and rumours of entire redesigns were brought up or invented.

If no one is talking about the requirement for such an aircraft to have a supersonic speed, then why do you think it's useful to point out that such an aircraft couldn't be made supersonic?
I mean, I fully agree with you. A large, supersonic, stealthy bomber would be basically impossible to build and procure in a realistic way from a cost perspective

But in the last few pages no one has touted the idea of H-20 being supersonic. You're the one who raised it, and have created this alternate discussion where the technicalities of whether a supersonic H-20 is viable from an engineering versus cost perspective.


Instead, the question has been around H-20 being able to carry large/long hypersonic weapons and the planform such an aircraft would need.

 

[latenlazy]

True no compromise between stealth and payload as the B-2 can attest. Stealth and speed is arguable. Pure flying wing (low speed) should be geometrically stealthier than something like J-36 (higher speed geometry) with two sweep angles. However this difference in ULO levels could be so marginal they can be overcome with materials. There are other elements in aircraft manufacturing that demand more attention than having one extra physical angle. These include gaps and gap management, moving surface management. J-36 is hingeless and utilises so many new breakthroughs in metamaterials, aircraft manufacturing techniques and moving surface/gap management. It could even be higher than B-21 since we don't know if B-21 employ hingeless and movable skins like J-36 already shown to be.

So even assuming no compromise between ULO stealth and payload and ULO stealth and speed ie you can make a supersonic "flat craft" like J-36. But there is compromise between bomber level payload + speed. There's obviously also compromise between agility and payload but bombers need not worry much for agility since that's asking for too much too soon.

H-20 will be able to only pick two of the three - ULO stealth, payload, speed. It can't have all three. Hence why I suggested that if it is true the PLA has two next gen "bombers" in development. They are H-20 which is ULO stealth and payload plus a hypothetical (J)H-xx which is payload and speed or ULO stealth and speed.

You are confusing speed and agility. Agility is about your control surfaces etc etc. Speed is just about your wing and fuselage shape. It’s not even about your T:W ratio. Supersonic bombers only have a T:W of like 0.4-0.5. A supersonic bomber doesn’t need to supercruise like the J-36, just dash. Nothing prevents a B-2 sized bomber with a narrower aspect ratio for higher speed from carrying a similar payload, especially if you decide to go with 4 WS-15 class engines.

 

[latenlazy]

H-20 should have no problem carrying munitions with 2000-3000km range even without an oversized IWB. If we are talking about a platform for carrying even larger missiles, then such a missile would be expected to have ranges of 5000-8000km, at which point we are no longer talking about a tactical system.

Uhhh why would you need an H-20 to carry a missile with the range of an intercontinental missile? You always have intercontinental ground missiles for intercontinental missile attacks.

 

[Tomboy]

Uhhh the planform I described is nothing like any of the flying wing configurations above.
When I say an evolved J-36 or X-47A planform, this is what I'm thinking about:

View attachment 158948

Furthermore, even if hypothetically the RCS of such an aircraft was "worse" than a B-21.... who cares? The H-20 would have a different role not to mention a vastly different size.

Unless of course meeting the RCS of B-21 is viewed as a design requirement, in which case that is just a design and engineering question and is eminently solvable because as I wrote previously, a H-20 designed around weapons bay length would not be a B-2 or B-21 or WZ-X style flying wing to begin with.

IMO, personally I'm thinking of this, a true diamond shaped aircraft which would allow for long weapon bay while also maintaining ELO as it also like B-21/B-2's shaping has only 4 angles where everything is aligned to. As I recall, I'm pretty sure some people were calling into question the survivability of B-21. I feel like having similar level of stealth should be a given at this point, US air defenses are still pretty potent, and they are actively trying to modernise it against stealthy aircraft.

 

[FriedRiceNSpice]

Uhhh why would you need an H-20 to carry a missile with the range of an intercontinental missile? You always have intercontinental ground missiles for intercontinental missile attacks.

My point was that while H-20 should be designed for launching hypersonic weapons with 2000-3000km range, a different platform should be utilized for even larger air launched hypersonic weapons with potentially 5000-8000km range, and that such a platform would diverge significantly from the H-20 in terms design characteristics and requirements. I interpreted the original discussion as concerning the need for a bomber to carry missiles even larger than the Beijing heavy hammer (13m+ missile, which I believed would be substantially larger than what would be required for 2000-3000km ramge missile).