PLA next/6th generation fighter thread

[gelgoog]

Also, thinking about it, remember how there were indications that the H-20 programme was on hold?

Instead of building H-20s, it might be that the PLAAF have decided that it is better to go for outright air superiority with the Chinese NGAD. That would cover Guam and potentially Darwin in Australia, which are both isolated "island" bases.

I suspect if there was a change in the H-20 program it would have been them changing it from using WS-10 engines to WS-15 engines.
That would enable them to further increase the range and maximum takeoff weight of the bomber.

A non flying wing airframe configuration, that you would need to have a high speed combat aircraft, would reduce aircraft range and payload making it suboptimal as a saturation bomber. Although there are other compromise solutions where you can you have both. Like with lifting body designs. In that case you can have both high speed and decently high range and high payload only at the expense of maneuverability. Which you would not need in a bomber. One example of such a design is the late Soviet Cold War Sukhoi T-4MS design.



In the case of a tactical fighter bomber I think they could just redesign the J-20 to have larger internal storage for bombs and fuel. Equip it with WS-15 engines standard from the onset and that would be more than enough.

 

[Gloire_bb]

I still think the US whole game plan for 6th gen is kind of misguided though. The smaller fighters should instead be drones and it is a horrible idea to use a small fighter as a drone controller. You will need a two seater aircraft minimum I think. The best option is probably two 6th generation aircraft. A light optionally manned fighter, and a heavy drone control/fighter bomber aircraft.

Nothing prevents smaller fighter to be an effective drone controller. Same reasons that allow CCAs in first place also free up pilot for control; second seat could be fitted even into WW1/2 fighters - second human isn't exactly that big and heavy. Human interfaces, datalinks and software don't gain from aircraft size.
Yes, less fuel - but it can be serviced and refueled with CCAs themselves. Also, by tinkering down performance requirements, making an efficient small cruiser isn't exactly impossible.

If anything, notion that it always should be a heavy, advanced manned component, accompanied by small expendable CCA is not a given.

Many age of Sail admirals commanded their battleline from a frigate, placed behind the line - in fact, other than personal inspiration/glory by example, everything else was better this way.

 

[Gloire_bb]

Carrier operations put hard limits on the size and number of aircraft you can field. The odds of USN unveiling something with a combat radius of ~3000km are extremely low.

Kind reminder that 2000+ missions were norm for long range/strategic carrier strike since 1950s to 1990s, and they often did so with bulky/heavy early nuclear weapons and with wasteful penetration part of flight(high supersonic dash for vigilante, long terrain hugging for intruder).
Carrier strategic bombers did it, intruders with refuel did it. It didn't became impossible later, just this whole mission disappeared in 1992.
Add JASSM-XR on top to even those old aircraft - and you're there.

USN can't do it now because of Shornet and f-35c limitations. If it's a requirement for a new aircraft, and with MQ-25 available already - it will be achieved without much research and development.

 

[Wrought]

Kind reminder that 2000+ missions were norm for long range/strategic carrier strike since 1950s to 1990s, and they often did so with bulky/heavy early nuclear weapons and with wasteful penetration part of flight(high supersonic dash for vigilante, long terrain hugging for intruder).
Carrier strategic bombers did it, intruders with refuel did it. It didn't became impossible later, just this whole mission disappeared in 1992.
Add JASSM-XR on top to even those old aircraft - and you're there.

USN can't do it now because of Shornet and f-35c limitations. If it's a requirement for a new aircraft, and with MQ-25 available already - it will be achieved without much research and development.

A-5/6 were dedicated strike aircraft with little to no A2A capability. And Super Hornets are actually bigger than Intruders. You can certainly get more range by sacrificing other aspects, it's true, but somehow I don't think USN is looking for a bomber with F/A-XX.

 

[Blitzo]

Nothing prevents smaller fighter to be an effective drone controller. Same reasons that allow CCAs in first place also free up pilot for control; second seat could be fitted even into WW1/2 fighters - second human isn't exactly that big and heavy. Human interfaces, datalinks and software don't gain from aircraft size.
Yes, less fuel - but it can be serviced and refueled with CCAs themselves. Also, by tinkering down performance requirements, making an efficient small cruiser isn't exactly impossible.

If anything, notion that it always should be a heavy, advanced manned component, accompanied by small expendable CCA is not a given.

Many age of Sail admirals commanded their battleline from a frigate, placed behind the line - in fact, other than personal inspiration by example, everything else was actually better.

The question shouldn't be whether a smaller fighter can be an effective drone controller, the question should be what the desired characteristics for an effective drone controller would be for the needs of a next generation combat aircraft.

After all, "smaller" and "larger" is relative. I could say that a 23m long fighter is a "smaller next generation combat aircraft" in the drone controller role, relative to a B-21 sized aircraft which is a "larger next generation combat aircraft".
Of course, I'm sure you probably have a smaller aircraft in mind than a 23m long fighter when talking about a "smaller fighter as an effective drone controller".


As for the benefits of larger aircraft size in the drone controller role -- I would argue that on the contrary, a larger airframe offers benefits for increased onboard organic processing and computing capability (important for the fusion and synthesis of large numbers of CCAs), more potent datalinks, and more future growth potential -- all the usual SWAP-C stuff.
While the end displays and human user interface doesn't need a larger airframe, everything else which feeds into it will indeed be rate limited by the size of the airframe.

As for fuel -- given your manned combat aircraft is the most important linchpin (command element) of your combat aircraft force composed of a rather large fleet of CCAs, minimizing the vulnerability windows of your manned aircraft (including aerial refuelling frequency) seems rather important to me.


Putting all of this another way, one can consider the "manned next gen combat aircraft" + "complementary CCA" aspect in two ways. Hold the "complementary CCA" as equal in both scenarios below:
1. Heavyweight manned next gen combat aircraft of equal quantity + complementary CCA force
2. Lighter weight manned next gen combat aircraft of equal quantity + complementary CCA force

In both scenarios, the capability and size of the complementary CCA force is the same, and the quantity of the "manned next gen combat aircraft" is also the same -- the only difference is that option 1 has a heavyweight/larger airframe, while option 2 has a lighter weight/smaller airframe.
For such a scenario, I cannot see why the lighter weight option would be preferable.

IMO, the lighter weight option would require financial reasons for it to make sense (e.g.: the absolute amount of budget is lower), or possibly if one wants option 2 to consist of a quantity of manned fighters which numbers greater than the heavyweight option. But one has to then make a serious case for justifying that the loss in per unit capability of a lighter weight manned aircraft is worth the quantitative benefit versus a heavyweight manned aircraft.



As it stands, I expect a 6th generation fighter for the PLA to desire substantial onboard unrefuelled combat radius, comprehensive stealth, a sizeable (albeit not outsized) weapons bay to carry out its own organic/onboard engagements at long range, substantial sensing and datalinking and processing capability with requisite SWAP-C to enable future growth potential of new avionics/datalinks/sensors etc. A degree of supersonic performance would likely still be required such as some degree of supercruise, but endurance/range would likely rank somewhat higher than it -- while traditional maneuvrability in the subsonic and transonic regimes would be relatively deprioritized than previous generations.

I would be surprised if that could all be achieved in a fighter which is not relatively large, twin engined, and adopting something like a big dorito/arrowhead.

Of course in the more distant future if the need for onboard weapons and even sensors is reduced due to greater maturity of offboard CCAs taking up the weapons and sensors role, then sure maybe you can go with a fighter which is on the smaller side while retaining good range, and onboard processing etc. But otherwise I can't quite see it yet, unless one is facing significant financial pressures and/or willing to trade individual aircraft characteristics for quantity.

 

[Blitzo]

I'm not a very good artist, but this drawing somewhat depicts my vision for a heavy weight J-XD proposition.

On the right, is the J-20 we all know. In the middle, is one of the tailless dorito air tunnel models we've seen under study over the years.

On the left, is my vision of a heavyweight J-XD based on that planform, scaled with the J-20 on the right. It comes to about 26m long, and a wingspan of 22m.
Most of it is self explanatory, but for sake of clarity:
- Black circle is cockpit (single pilot sized)
- Brown rectangles are for landing gear
- Green rectangles are for weapons bay -- main ventral bay and two small side bays
- Yellow curvy thingy is approximate air intake path -- starts ventrally and S ducts dorsally (think YF-23) to the engine
- red rectangle/circle is engine (I drew them as ovals in the frontal aspect picture, pretend they are circles)




Bits of note:
- Main ventral weapons bay I envision as being sized to enable carriage of up to six VLRRAMs like PL-17s (which would not take up the full length of the bay in a 6x1 configuration), or twelve PL-15s (which would take up the full length of the bay in a 6x2 configuration). Or it can carry the equivalent number of the new BVRAAM which J-20 is designed to carry six of in place of four PL-15s, which would be eighteen "PL-Xs" (in a 9x2 configuration)
- Side/ventral bays are for a BVRAAM -- either a single PL-15 or PL-X, but in future iterations could be replaced as avionics bays or a DEW bay.
-I haven’t depicted sensors, EW and datalink antennae, but they would consist of a number of distributed arrays around the airframe but also have a traditional radome sensor as well.
-Many of the specific details and geometries are obviously omitted because I am bad at drawing
(intake geometry, specific contours, etc)
-Overall this aircraft would of course be much heavier than a J-20 and have a slightly larger total footprint, however I consider it to still be a “tactical” sized aircraft, albeit on the larger size
-Substantial internal volume for fuel, avionics, and SWAP-C for future growth
-I haven’t depicted control surfaces, but they would essentially be the same as what the wind tunnel model or the similar Lockheed RESTORE has (moving wingtips, slats, trailing edges etc), see below images





This isn’t meant to be unfalliable, more a rough depiction of what I think the priorities of a heavy weight J-XD. If the PLA does go for a heavyweight J-XD option, to be honest I think what I depicted may be a bit large – perhaps something in the 23-24m length rather than 26m length would be more plausible.



That said I do think some sort of tailless arrowhead/dorito seems like a plausible configuration to pursue. I’m open to the idea of dorsal fold down V tails that “fold” against the fuselage smooth during normal operation and “fold out” when needed like take off or landing

 

[Gloire_bb]

As for the benefits of larger aircraft size in the drone controller role -- I would argue that on the contrary, a larger airframe offers benefits for increased onboard organic processing and computing capability (important for the fusion and synthesis of large numbers of CCAs), more potent datalinks, and more future growth potential -- all the usual SWAP-C stuff.

There are interesting questions here: whether airframe size matters for sufficient processing(and should it even be done specifically on the control node), whether datalinks are affected by size/power relative to the mission(is there a need to increase datalinks to those levels?), and, perhaps most importantly, are the most important future gains are to be gained by hardware(and not software) on the control node?
I won't challenge those notions outright, but I still want to put a question mark over all of them for us to consider.
The question, IMHO, is not just in the ideal CCA - it's obviously the best and the most capable one, preferably one that can kill everything even without CCAs. The question, IMHO, is how to preferably keep the actual posture (with possible geopolitical requirements - again, up to and including chance for forward basing), not try to change it and compensate with CCAs. CCAs are substrate of future air power, but I don't think they're a sufficient reason to change the classification of the manned element.
Limiting the latter to just rear-based heavy, for example, arises all the same questions about its reaction time and modus operandi - what good such teaming is, if CCAs are fighting alone because the control node couldn't make it in time?
Or, more stupid still, we aren't fighting anything and we just need to check with the human eye on a civilian liner without a transponder and not answering anything.

Apart from question of the (single) optimal size of the future platform and the need to urgently go to it, it also a question about the need to go for a new heavy platform at this point in time(J-20 is just over 5 years old): new platform gives us more stealth and more power(new generation engines) - both are very high investments in fields where China is playing catch-up (i.e. there are significant risks of programs underperforming). Language on DEWs, for example, recently got toned down quite a lot - apparently pew-pew dreams on agile platforms in the skies aren't exactly as easy as they seamed.

Software, comm tech, and CCAs on the other hand are exactly Chinese strengths and often relative weakness of the competition, but just as importantly - they're areas of main capability growth. Like, try a G60/Xingwang aircraft dish on it and CCAs, or play a software game.
We know how western car manufacturers struggle with software, for example, and we know how LM struggles with software that should've been already here.

I.e. in the case of a heavy class platform, there is already an up-to-date platform with modern(integrated) architecture, conformal datalinks and space for future growth.
At the moment, it makes more sense to update smaller nodes, where hardware is absolutely behind the curve - and I would like to refer here to the study you've mentioned, which was a study of a single-engined fighter with minimum rational weapon load (4 MRAAMs) in a voluminous integrated fuselage.

 

[Blitzo]

There are interesting questions here: whether airframe size matters for sufficient processing(and should it even be done specifically on the control node), whether datalinks are affected by size/power relative to the mission(is there a need to increase datalinks to those levels?), and, perhaps most importantly, are the most important future gains are to be gained by hardware(and not software) on the control node?
I won't challenge those notions outright, but I still want to put a question mark over all of them for us to consider.
The question, IMHO, is not just in the ideal CCA - it's obviously the best and the most capable one, preferably one that can kill everything even without CCAs. The question, IMHO, is how to preferably keep the actual posture (with possible geopolitical requirements - again, up to and including chance for forward basing), not try to change it and compensate with CCAs. CCAs are substrate of future air power, but I don't think they're a sufficient reason to change the classification of the manned element.
Limiting the latter to just rear-based heavy, for example, arises all the same questions about its reaction time and modus operandi - what good such teaming is, if CCAs are fighting alone because the control node couldn't make it in time?
Or, more stupid still, we aren't fighting anything and we just need to check with the human eye on a civilian liner without a transponder and not answering anything.

I think those are certainly interesting questions -- I would argue whether those are questions which can be afforded to be asked by national military forces when developing their next generation manned fighter aircraft based on current technologies, or whether they would consider it prudent to develop a larger fighter that had the ability to accommodate greater SWAP-C and associated hardware upgrades as an option if needed, rather than assume that advancements will be weighted in favour of software or offboard capabilities and not having the greater airframe size and growth potential when the rubber hits the road.

I don't see how heavyweight fighters would necessarily be "rear based" relative to lightweight fighters in context of operating alongside CCAs, or why heavyweight fighters would be less optimized in reaction time or modus operandi?
If anything a heavyweight fighter should have superior endurance and persistence.

The only difference is if one is procuring a larger number of lightweight fighters relative to heavyweight fighters due to financial reasons, which may impact availability/sortie generation depending on what the difference in respective fleet size is.

Apart from question of the (single) optimal size of the future platform and the need to urgently go to it, it also a question about the need to go for a new heavy platform at this point in time(J-20 is just over 5 years old): new platform gives us more stealth and more power(new generation engines) - both are very high investments in fields where China is playing catch-up (i.e. there are significant risks of programs underperforming). Language on DEWs, for example, recently got toned down quite a lot - apparently pew-pew dreams on agile platforms in the skies aren't exactly as easy as they seamed.

I would argue a new platform gives more SWAP-C for subsystems, as well as endurance and range, with those being more important than the advancements in stealth and power relative to J-20.
By the time J-XD may be ready, J-20 will have been in service for some 15+ years. Of course, J-20s will still be in service and relevant and have seen upgrades, but a 15-20 year new generation service cycle is about normal, and operating alongside substantial numbers of the prior generation is also normal (J-20s operating alongside J-16s, J-10C and other upgraded 4th gens for example -- no reason why J-XD couldn't operate alongside large numbers of upgraded J-20s as well as large numbers of CCAs).

I don't think DEW was considered a major component of 6th generation capabilities for quite a few years now.

Software, comm tech, and CCAs on the other hand are exactly Chinese strengths and often relative weakness of the competition, but just as importantly - they're areas of main capability growth. Like, try a G60/Xingwang aircraft dish on it and CCAs, or play a software game.
We know how western car manufacturers struggle with software, for example, and we know how LM struggles with software that should've been already here.

It's not just a matter of software -- many of the struggles with F-35 Block 4 is related to the TR3 hardware, which in turn is related with the smaller size of the aircraft and more limited SWAP-C.
More importantly, while areas of offboard systems have substantial room for growth, currently they remain relatively immature, therefore possessing a sufficiently capable organic manned fighter with room for growth capacity and redundancy if other offboard systems do not pan out, or if offboard systems are compromised/targeted in a conflict, just seems like a prudent and low risk route to take currently.
Maybe when the 7th generation of fighter aircraft emerge, CCAs and super constellations and AI will be so advanced that the manned fighter only needs to serve as a controller without any meaningful onboard weapons or sensors of its own, but I think we are far from that yet.

I.e. in the case of a heavy class platform, there is already an up-to-date platform with modern(integrated) architecture, conformal datalinks and space for future growth.
At the moment, it makes more sense to update smaller nodes, where hardware is absolutely behind the curve - and I would like to refer here to the study you've mentioned, which was a study of a single-engined fighter with minimum rational weapon load (4 MRAAMs) in a voluminous integrated fuselage.

I would actually argue the fact that we have access to that specific paper means that it's probably rather likely that the internal configuration depicted probably isn't going to be what the J-XD will be, and is just a generic stand in for the aerodynamic study.


All of this isn't to say the idea of a "lighter weight" J-XD is infeasiable, nor am I inherently philosophically against the idea.
But IMO there is a good reason to believe that a lighter weight J-XD at this stage is the much more unlikely option that the PLA would be weighing up at this stage.
It's a reasonable default/null hypothesis position to take for now, to expect J-XD to be a larger, heavier weight manned fighter rather than a smaller, lighter weight manned fighter. If new information or rumours comes to light to change that idea, then of course it can be reassessed.

 

[tphuang]

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I've been discussing this article with a couple of people

Matt Milas, president of Honeywell Defense and Space, says he is concerned that program officials are favoring the more radical upgrade option, which he warns would require replacing the cooling system’s “plumbing”—the network of tubes bearing a liquid coolant that snakes through the F-35’s interior, including through the jet’s load-carrying bulkheads. “That presents a lot of problems because now you have to swap out some of the plumbing,” Milas tells Aviation Week. “When you swap out the plumbing, you have to take the skins off the wings and things like that.”

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So far, two companies have publicly expressed interest in the PTMU overhaul effort, albeit with very different proposals for how to turn down the temperature of the stealth fighter.

Honeywell builds the F-35’s current cooling system, dubbed the Power and Thermal Management System (PTMS), a single apparatus that combines an auxiliary power unit, environmental controls and emergency power system. Its proposed solution would upgrade the aircraft’s heat exchangers and improve the flow of liquid coolant, but be carried out by moving around parts of the existing system and upgrading key elements — a tactic Honeywell has said could tamp down cost and development risk.

Company officials have said the proposed changes would provide the cooling necessary to offset 80 kilowatts of heat generated by the F-35’s subsystems, an objective set by the JPO.

Henry Brooks, president of Collins Aerospace power and controls said, “A new power and thermal management system is not only critical to the current overall performance of the jet, but it will be essential to enabling future requirements well beyond Block 4.”

Just take a look at how much of a pain it is to get thermal management system right on F-35. This is directly an issue caused by having a smaller airframe. The collins aerospace solution sounds like it would require even more change. With a larger airframe like J-20, you can just have more interior space for cooling & power generation alongside all the high end electronics you'd want to stick inside the airframe.

J-20A itself already needs to be a pretty big upgrade over original J-20. And we've seen them add a hump at the back to give it more interior space. And we've seen the picture of J-35 mockup vs J-15B. It's huge. So, because China started J-20 and J-35 later than F-35, it had the foresight that you need larger aircraft to carry all this stuff.

And with next generation, you have more powerful engine & more efficient power modules. Which means, you can stick in much more powerful EW suites, communication suites, computational power and things like that. Even if you don't about things like range, having more interior space is huge for having enough room for all this other stuff.

Having a larger wings presumably allow you to stick EW pods operating on different band further away from each other, so they don't interfere with each other as much. Although I guess this is not as critical of a requirement.

It also gives you more surface area to circulate the liquid cooling so that it's spread across the entire aircraft and doesn't increase your IR signature as much.

But the key here is that you are going to build the biggest possible aircraft while still retaining enough maneuverability (at least comparable to 5th gen). And the more powerful engines will allow you to do that.

So, if the next generation engine has 25% more thrust than previous generation (145kN vs 181kN), then you can have an aircraft that's 20 to 25% heavier. That gives you a lot of room to work with. I would keep the weapon bay as it is.

 

[Gloire_bb]

F-35 isn't a small airplane, and this problem isn't about smaller aircraft. It's about screwed up design.
This happens with aircraft of any size.