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

Gloire_bb said:

You aren't getting away from them by speed alone whe you're detected. BVRAAM is faster, and it doesn't really need J-36 for that, J-16 will do.

You can dart in and out faster than system can respond, but the only positive difference will be if it sees you regardless of your stealth. Otherwise, subsonic VLO will be detected later. And if it's this kinda of all-seeing radar network, you still won't go for supersonic design, but rather for something like low altitude dart Blitzo mentioned several pages ago.

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Speed just means you don’t need to spend a lot of time in places you shouldn’t be hanging around in.

And the cruise means that you can sustain evasion from something like the J-36 (including its missiles) if you have a head start. For example, there is talk of the B-21 operating from Guam — a J-36 could chase a B-21 all the way to Guam, and still be able to loiter overhead. Or chase it for 2000km+ as it escapes back to AK or HI.

The PLA was probably expecting that “full size” NGAD from Lockheed too. Not the F-47 poor man’s compromise.

GTI said:

Speed just means you don’t need to spend a lot of time in places you shouldn’t be hanging around in.

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It isn't "just". Speed comes with:
1, less effective plane forms for radar stealth, much higher stability requirements, problems with RAMs and more required air flow to engines. You're outright less stealthy, and given how finicky VLO stealth is - we're speaking about losing orders of magnitude in stealth(i.e. detection range will increase several times). Your "places you shouldn't be in" just get larger.
2, you're turning much less efficient i.e. you aren't nearly as free in choice of optimal flight paths around defenses.
3, you're much brighter, and worse still, you are suddenly not just somewhat visible in LWIR, but also appear in MWIR. Which means every f-35, J-16 and likely J-20A/35 around.
4, and how much speed are we talking about? Other than Hustler, pen speed for majority supersonic heavy bombers was(is) at most M=1.4. It's not that terribly faster than M=0.95. is this x1.5 really worth 2-3-4 times increase in danger spaces?

And for all this, you pay a lot.

Gloire_bb said:

It isn't "just". Speed comes with:
1, less effective plane forms for radar stealth, much higher stability requirements, problems with RAMs and more required air flow to engines. You're outright less stealthy, and given how finicky VLO stealth is - we're speaking about losing orders of magnitude in stealth(i.e. detection range will increase several times). Your "places you shouldn't be in" just get larger.
2, you're turning much less efficient i.e. you aren't nearly as free in choice of optimal flight paths around defenses.
3, you're much brighter, and worse still, you are suddenly not just somewhat visible in LWIR, but also appear in MWIR. Which means every f-35, J-16 and likely J-20A/35 around.
4, and how much speed are we talking about? Other than Hustler, pen speed for majority supersonic heavy bombers was(is) at most M=1.4. It's not that terribly faster than M=0.95.

And for all this, you pay a lot.

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I’m glad you actually tried to clarify / ask about the theorised specifications.

Top speed / supercruise in the region of M 1.4 to 1.8 is all that’s being put on the table here (maybe even M 1.2). There are no problems with RAM, stealth, stability etc. that would be insurmountable [for China].

I won’t even entertain discussion on it.

While a large J-36 is by no means easy, this absurd notion that it’s technologically unachievable, or that hypersonic or high supersonic speed is required, is puzzling.

GTI said:

Top speed / supercruise in the region of M 1.4 to 1.8 is all that’s being put on the table here (maybe even M 1.2). There are no problems with RAM, stealth, stability etc. that would be insurmountable [for China].

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You're looking at it as some sort of demonstration, like from space race. China isn't doing things because they're hard instead of easy here, strategic bombers of all kinds are an 80 years old achievement.
China's getting a capability. Not absolutely urgentlg, but as of mid-2020s lack of it already harms China directly. The most optimal path to this capability is subsonic flying wing.

GTI said:

While a large J-36 is by no means easy, this absurd notion that it’s technologically unachievable, or that hypersonic or high supersonic speed is required, is puzzling.

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It isn't unachievable. It will just produce a worse result, at much higher technical risk, for more money, just to satisfy egos. Which is a type of well-intentioned mismanagement more harmful than actual corruption.

latenlazy said:

I don’t think you guys understood what I was pointing out. Profiles C and D have the exact same frontal aspect shaping but do not have the same RCS on at frontal aspect. The same is true for A and B My point is “edge alignment” is not the explain all heuristic you’re making it into.

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I'm not sure you understand what "edge alignment" is. It doesn't mean the edges are all aligned behind each other, so the they look the same from a certain angle, e.g. the frontal aspect, it means they're aligned in the same angle relative to each other, i.e. forming many parallel lines.

People tend to think radar waves bounce off of objects like lights on a mirror, but that's not how it works. EM waves can actually hit an object and then bend around the object, traveling along its surface. It would then only scatter when the surface is no longer present, i.e. at the trailing edge of the object. That's why in post #4649 two pages back the EM waves are shown to be bouncing off of the trailing edge, not the leading edge. This is also why larger planes can be just as stealthy or even stealthier than smaller ones. EM waves have to travel longer on a larger plane before scattering at the trailing edge, giving RAM more time to absorb them. More to the point of this post, this is why an object that looks the same from the frontal aspect can have different RCS.

It’s not really an ego problem. If what’s being posited is true, that expanded air intercept capabilities ala J36 air frigates and networked ISR ala satellite/starlink/CCA make any subsonic aircraft as good as dead or extremely vulnerable to interdiction —VLO, ULO, ELO whatever madeup term is being thrown around now — then either you make the aircraft survivable (by going fast) or you might as well not make a bomber at all. (yay for the PLARF I guess, yay for strike aircraft, rip for H20)

tldr; the point is that B2 B-21 type aircraft and evolutionary type development along this doctrinal tree is dead. these aircraft are cooked in a 6th gen fighter populated airspace.

dingyibvs said:

I'm not sure you understand what "edge alignment" is. It doesn't mean the edges are all aligned behind each other, so the they look the same from a certain angle, e.g. the frontal aspect, it means they're aligned in the same angle relative to each other, i.e. forming many parallel lines.

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I’m not sure you understand what I was pointing out? Where did I suggest edge alignment means the “edges are all aligned behind each other”.

The density and capability of ISR networks drops off "rapidly" as you get further from territory you control and further into contested / no-man's territory for reasons of survivability and sustainability. A subsonic aircraft that is a sitting duck at one location can be an invisible archer a few hundred nautical miles further back. At which point the determining characteristic for mission success is not speed but stealth, range (and the expanded routing options), and payload. All of which face significant trade-offs once you start venturing into supersonic speeds.
Sure, you could make a supersonic bomber that gets out of dodge fast once it blows its load. But can this supersonic bomber carry enough munitions to maximize pkill? Can it remain undetected long enough to prevent pre-emptive interception? Can its payload cover the entire distance to target without being unceremoniously shot out of the sky? Does it have legs long enough to route around enemy ISR nodes to get as close as possible?

latenlazy said:

I’m not sure you understand what I was pointing out? Where did I suggest edge alignment means the “edges are all aligned behind each other”.

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When you said "Profiles C and D have the exact same frontal aspect shaping but do not have the same RCS on at frontal aspect." That seems to imply that frontal aspect shaping is the key determining factor on frontal aspect RCS, or am I understanding you wrong? What did you mean by edge alignment if that's not the case? Clearly the trailing edges for all 4 profiles are aligned at different angles.

Nautilus said:

The density and capability of ISR networks drops off "rapidly" as you get further from territory you control and further into contested / no-man's territory for reasons of survivability and sustainability. A subsonic aircraft that is a sitting duck at one location can be an invisible archer a few hundred nautical miles further back. At which point the determining characteristic for mission success is not speed but stealth, range (and the expanded routing options), and payload. All of which face significant trade-offs once you start venturing into supersonic speeds.
Sure, you could make a supersonic bomber that gets out of dodge fast once it blows its load. But can this supersonic bomber carry enough munitions to maximize pkill? Can it remain undetected long enough to prevent pre-emptive interception? Can its payload cover the entire distance to target without being unceremoniously shot out of the sky? Does it have legs long enough to route around enemy ISR nodes to get as close as possible?

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This discussion has gotten extremely silly. Everyone is trying to do imaginary engineer around imaginarily projected constraints.

dingyibvs said:

When you said "Profiles C and D have the exact same frontal aspect shaping but do not have the same RCS on at frontal aspect." That seems to imply that frontal aspect shaping is the key determining factor on frontal aspect RCS, or am I understanding you wrong? What did you mean by edge alignment if that's not the case? Clearly the trailing edges for all 4 profiles are aligned at different angles.

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If C and D have the exact same frontal shaping but *do not* have the same RCS, that would be implying frontal aspect shaping is *not* a singularly definitive determinant.

If it was as simple as “trailing edges must also align” then A wouldn’t have a lower RCS than B (see attached). Once again, you guys are over-extrapolating off rules of thumb that aren’t that useful for gauging real world designs. The 2D planform is not irrelevant but we also cannot draw definitive conclusions about real world designs based only on 2D planforms.

Insofar as people want to say “well Northrop went with the same planform for the B-21 and all these other flying wings exist” yes of course if the planform has reliably favorable attributes it will be used *but that does not mean we can conclusively say other planforms cannot attain similar levels of RCS reduction provided sufficient work is put into them on other aspects of RCS design outside of the 2D planform*. I am absolutely sure the 2D planform used by the B-21 is excellent for minimizing RCS and I am sure that if your most important engineering requirement is RCS reduction this the best place to start, but this does not mean you can then also say with categorical confidence “any other plane not using this 2D planform cannot possibly reach the B-21’s RCS” *because these planes and their RCS are not only their 2D planforms*.