Chengdu next gen combat aircraft (?J-36) thread

[AndrewS]

Browsing through Reddit LCD forum because I am bored. I saw this post by SFMara which is kind of interesting and counter intuitive to me



While there is certain logic to this, it seems just a bad idea to build a central controlling manned fighter that isn’t as good as your chief adversary. Smaller aircraft might be able to operate from more austere air bases but they just don’t have the power generation to compete with something like J36. And it would seem to me that if this is what US defense establishment draws up to counter China’s 6th gen, they will be at a huge disadvantage in EW and that is disastrous when it comes to missile attack that can also come from mainland assets.

I don't think the USAF have a choice, if they are rational.

Current specifications for NGAD require a 3000km operating range.
So it can reach China when operating from Guam and the rest of the Second Island Chain.
The assumption is that these airbases are available because it is too far for the Chinese Air Force to establish air superiority.

But now?

No matter how many NGADs there are, only a handful of bases are available in the Second Island Chain.

And given that the Chinese Air Force (with the J-36) and Rocket Force can keep those bases under attack, just like in the First Island Chain.

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Smaller aircraft can compete with a J-36 in terms of EW. But they will have to accept lower speeds and performance elsewhere. And yes, they will have to accept that their airbases in the First Island Chain will be under attack.

 

[sevrent]

I don't think the USAF have a choice, if they are rational.

Current specifications for NGAD require a 3000km operating range.
So it can reach China when operating from Guam and the rest of the Second Island Chain.
The assumption is that these airbases are available because it is too far for the Chinese Air Force to establish air superiority.

But now?

No matter how many NGADs there are, only a handful of bases are available in the Second Island Chain.

And given that the Chinese Air Force (with the J-36) and Rocket Force can keep those bases under attack, just like in the First Island Chain.

---

Smaller aircraft can compete with a J-36 in terms of EW. But they will have to accept lower speeds and performance elsewhere. And yes, they will have to accept that their airbases in the First Island Chain will be under attack.

We dont know what range requirment it is but I suspect 1000nm as a bare minimum baseline, which shouldnt be too hard. F-35 using NGAP tier engines would be boosted from 770nm CR to just around 1000nm alone in that tiny airframe. Something YF-23 sized should be able to push 1500+nm quite comfortably which would add up alongside the quoted $300 million price tag. F-22 back then was around $210 million in comparison.

If they pursue NGAS that would as well that allow them to relax range requirement even more. Time will tell in a few months I suppose.

 

[Stealthflanker]

Also, how does your calculated 210km range reconcile with THAAD's claimed detection range of many thousands of kms. Are the thousands of km range measured against >>0dbsm targets? My understanding of BMD radars is that they take advantage of the very low background noise level from objects in space to achieve their detection range. Would this make them more vulnerable to increased noise from jamming?

Regarding the target, the thousand km range for THAAD refers to the "Barrier Search" mode. For which the radar search the horizon for "pop up" missile.




As ballistic missile ascend to the apogee it will "pass" the search fence, during this phase which usually still boost phase, the missile is still intact (not yet releasing its PBV or HGV) and the BMD Radar may have clear look at the missile's side. Which RCS can be approximated by Cylinder, and it's very high.

Simple approximation for cylinder RCS :



a is the radius of the cylinder, L is length while lamdba is wavelength. Using the previously established frequency of TPY-2 and a model ballistic missile with body diameter of say 1.5 m or 0.75 m in radius and 10 meters in length yield RCS value of some 500000 sqm. Thus making it relatively easy to detect during boost phase.

Thus for the previously established range for TPY-2 that 210 km for 0.01 sqm which i assume the warhead. It can pick the missile in about :

R=210*(523598/0.01)^(1/4)
R=210*85
R=17850 km

or 85 times longer according to 4th root laws.

 

[kurutoga]

We dont know what range requirment it is but I suspect 1000nm as a bare minimum baseline, which shouldnt be too hard. F-35 using NGAP tier engines would be boosted from 770nm CR to just around 1000nm alone in that tiny airframe. Something YF-23 sized should be able to push 1500+nm quite comfortably which would add up alongside the quoted $300 million price tag. F-22 back then was around $210 million in comparison.

If they pursue NGAS that would as well that allow them to relax range requirement even more. Time will tell in a few months I suppose.

In the 2020 design NGAD the ambition of USAF was "cruising in West Pacific" but in their newer smaller proposal that requirement is dropped. The big challenge is, with the presence of J-36 and new systems from PLA, if NGAD range requirement is lowered, US forces will have to retreat to Aleutian and Hawaii. Congress may not say so explicitly, but the people on the ground who fight the war have to accept the fact. I think the range of F/A-XX is also critical because it decides the location of the carriers.

Distance between 2nd and 3rd island chain is huge. IMHO Trump has to negotiate with China if he wants to keep US influence in Japan, or, the only other option is an expensive, no-compromise NGAD

 

[BoraTas]

This is very interesting and informative. I am aware of the decreased sidelobe effectiveness but I didn't know what a reasonable sidelobe gain would be for TPY-2 which is why I calculated the power density.

In David Adamy's equation, combining terms related to the jammer we have -Pj-Gj-Grj+20log(Dj)+J/S. Putting in the values I got a -4.84dB, 10^(-4.84/40)=0.756, so a 24.4% reduction in range? It seems that some the very low Grj plays a big part here.

Also, how does your calculated 210km range reconcile with THAAD's claimed detection range of many thousands of kms. Are the thousands of km range measured against >>0dbsm targets? My understanding of BMD radars is that they take advantage of the very low background noise level from objects in space to achieve their detection range. Would this make them more vulnerable to increased noise from jamming?

The TPY-2 has a mode called forward based that scans very very slowly with a massive dwell time. The TPY-2 can switch between terminal and forward based modes within hours which is why China made the TPY-2 in SK a problem. It is used for early warning and decoy discrimination in that mode. It is especially important for the latter since it would see the missiles going to North America for a long time with high SNR and from multiple aspects.

I think in case of a Sino-American War unless SK declares strict neutrality from the start that THAAD installation in SK would get DF-27'd just in case. The THAAD has an engagement floor at reportedly around 40 km. At shorter ranges such a low altitude shouldn't be a problem for the DF-27

 

[Deino]

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antwerpery

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Thursday at 5:46 PM​

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The J36 will be at the center of China's combat web and will only be used in large scale conflicts. In a large scale conflict, it's gonna to be surrounded by hundreds of other aircraft and probably personally always be escorted by a squadron of drones. Kinda like a carrier strike group. Asking why it can't dogfight is like asking why an aircraft carrier doesn't have anti-submarine and anti-missile capabilities like a destroyer or frigate.​

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kurutoga

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Yesterday at 12:43 AM​

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US has the lead in low orbit constellation: Starlink​

Stoa1984's Commentary

Again, if one uses the tea set analogy, it would be accurate to compare the J-36 stealth fighter to one of the many teacups while the core central asset would be the orbital DEW WMD array, made of a mix of dual-use civilian-military Starlink/Bluebird-type platform comprising Guowang/GW60 and more Proliferated Low Earth Orbit (pLEO) megaconstellations.

It would be utterly futile to discuss any future hypothetical conflict scenario while totally overlooking this most powerful asset.

And as a matter of fact, this orbital DEW WMD array would not only be able to prosecute a war but conclude it with a decisive victory within a few minutes after start. As long as the PLA doesn't fight the only other superpower, that is the U.S.

Indeed, what one needs to understand is that the first ~30'000 Guowang/GW60 satellites will be followed in the second and third phases by even more capable platforms.

Here the analogy with the documented U.S. space program:

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Phased arrays comparison of Globalstar Gen2, Iridium-NEXT, Starlink Gen 2, Bluebird Block 1 and Bluebird Block 2.

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• Globalstar Gen2: 1.4m x 1.4m Phased Array
• Iridium-NEXT: 2m x 2m Phased Array
• Starlink Gen 2: 2.7m x 2.3m Phased Array
• Bluebird Block 1: 8m x 8m Phased Array
• Bluebird Block 2: 15m x 15m Phased Array

This indicates that SpaceX will soon upgrade its fleet of 42'000 satellites to the next Starlink Gen 3 with 8m x 8m Phased Array antennas. And ultimately to the still undisclosed Starlink Gen 4 (?) with 15m x 15m Phased Array antennas although in a more limited numbers (60 Bluebird Block 2 announced by AST SpaceMobile so far).

The size of these Bluebird Block 2 with 15m x 15m Phased Array antennas will be comparable to the Cold War early warning radar PAVE PAWS (PAVE Phased Array Warning System). The peak transmitted power of PAVE PAWS were rated at 580 kW.

Add to this as the teapot, the future Chinese space solar power station (SSPS-OMEGA), able to steer MW level microwave beams on ground targets.

Can we stop spreading BS and nonsense?

 

[iewgnem]

Probably a clean-sheet stealthy dedicated refueling UAV would be better overall IMO instead of re-engineering J-36 into it.

Frankly, I'd be surprised if something already isnt in the works.

We will likely see alot of platforms and munitions pop up over the next few years that will make up the eco-system of the 6th gen PLAAF.

PLA historically hasn't been big on single purpose clean sheets, e.g. H-6 family, Y-8/9 based platforms, Y-20 based platforms and Flanker variants.

Yeah clean sheet can be done, or maybe it's better to use H-20 as base for stealth tanker, but I would not rule out a J-36U buddy tanker / drone tanker.

 

[AndrewS]

In the 2020 design NGAD the ambition of USAF was "cruising in West Pacific" but in their newer smaller proposal that requirement is dropped. The big challenge is, with the presence of J-36 and new systems from PLA, if NGAD range requirement is lowered, US forces will have to retreat to Aleutian and Hawaii. Congress may not say so explicitly, but the people on the ground who fight the war have to accept the fact. I think the range of F/A-XX is also critical because it decides the location of the carriers.

But even if the F/A-XX is going to match the notional 3000km range of the larger land-based NGAD, it doesn't change the balance of power.

At the very most, the US Navy could have 3 deployed carriers (aka floating airbases) at a distance of 3000km.

But China should be able to control the air at that distance, because it can field a larger force of J-36.

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Given that the J-36 is already flying, that implies it will be in service ahead of NGAD or F/A-XX.

At the same time, we'll probably see China "outspending" the US in arms race and building more 6th gen aircraft.

If you ignore the undervalued exchange rate controlled by the Chinese government, then in terms of actual output of goods and services, the Washington-based World Bank purchasing power parity numbers suggest the Chinese economy is actually 25% larger than the US economy.

And if you correct for measurement differences (such imputed rent in the US and the undercounting of Chinese consumption figures), the indications are the Chinese economy is somewhere between 50-100% larger than the US.

Distance between 2nd and 3rd island chain is huge. IMHO Trump has to negotiate with China if he wants to keep US influence in Japan, or, the only other option is an expensive, no-compromise NGAD

If they're still planning on operating NGAD from the Second Island Chain, it doesn't matter how expensive or no-compromise the NGAD is. Nor does it really matter how many NGADs are built.

Let's say there is a better NGAD and they concentrate enough to retain local air superiority around Guam, the limitation is still the number of airbases. Those airbases and their runways will still be under attack, which means more aircraft will be trapped on the ground, unable to takeoff and therefore vulnerable to follow on attacks.

And trying to operate an Air Dominance aircraft from the Third Island Chain will require something bigger than the B-21. Even if technologically feasible, the cost is going to be unaffordable. NGAD at $300 Mn is already being called unaffordable, and the B-21 is $800 Mn

 

[mack8]

To get back in time a bit, is there more info/artwork or anything of value about the 2021 Chengdu triangular aircraft seen in satellite pictures? Any guesstimates as to it's size, how many engines, when exactly it might have flown etc.?

 

[MarKoz81]

Part 4: As chief designer Wang Haifeng said, EW will be a key feature for 6th generation. Here I do some back of the envelope calculation on how EW will degrade US attempts at BMD and explain why speed and altitude will keep the J-36 survivable where the B-21 cannot.
View attachment 142596
The one hundred trillion times (-140dB) is a bit of an extreme case (i.e. 1500km detection againt a -20dBsm RV). Things improve a bit to "only" ten billion times (-100dB) when the RV is at 150km.

Previous infographics on the J-36:
Definition of 6th gen and possible J-36 missions
Concepts of PLAAF air superiority oriented combat drones
J-36 in OCA (will be updated to include drones)
J-36 in DCA (updated with drones)
J-36 tactics vs B-21

Supercruising into delusion, deploying stand-off nonsense and defending with all-aspect ignorance. This is 7th gen of awful.