PLA next/6th generation fighter thread

[Nx4eu]

how about the blockage of air flow into intakes in that position right behind cockpit?

In my model the intake isn't fully blocked by the cockpit, air flow separation and turbulence is certainly a possibility especially in high AoA maneuvers. (In a real aircraft, these would definitely been solved beforehand). I however don't possess fluid simulation software nor a wind tunnel to demonstrate my fictional model.

Guess I have to put a disclaimer on my model, everything Except the intake position has been explicitly hinted at, the intake position on my model was wholly decided by me to make the design appear "ugly" as it was rumored months ago. Do not construe it's location as an accurate depiction of the real aircraft.

I don't know what the purpose of this aircraft is, neither it's role or abilities as I do not work for AVIC, but based on the rumors of it being large aircraft with 3 engines with broad LO stealth capabilities, I purposely modeled it as if it were like a tactical bomber with a focus on stealth, speed, and range over a multirole/air superiority fighter. This could be completely wrong. But those are my reasonings to my intake configuration.

 

[SlothmanAllen]

Three engines would sure be interesting to see! Could this type of arrangement point to something more exotic than just three turbofan engines? Maybe some sort of combined cycle system?

I guess I would put myself in the skeptical of three turbofan engine arrangement. Though I am not aerospace engineer so it really doesn't matter what I think . That pessimism is really just based on the fact that no other modern aircraft use that arrangement and it seems like it would be expensive to maintain. I think that comes from a time when engine technology was not mature enough and once turbofan technology matured, everyone moved to either two or one engine set-ups for fighter aircraft.

 

[Blitzo]

That configuration is ridiculous based on what we know so far imo.why need 3 engines?

You should read like the last 40 pages of the thread first.

 

[AndrewS]

In light of the development across the Pacific, would China's three-engine J-XD run into similar problems, even at a smaller degree and even with a more stellar financial management capabilities and less tolerance for corruption within the PLA compared to the Pentagon? Therefore, in retrospect - Would a high-low pair of J-XD models similar to the J-20/A-J-35A pair which are also paired with UCAVs be more affordable, balanced and effective for the PLAAF, instead of a sole heavy J-XD model paired with UCAVs?

A few comments here

1. Presumably a J-XD with 3 engines would have a significantly longer range, sufficient for operations to Guam on the 2IC some 3000km away. For operations in the 1IC (at most 1500km), smaller planes with 1 or 2 engines would be sufficient Sometime after 2030, I expect there to be enough J-20 and J-35 (accompanied by CCAs, UCAVs, 4th gen fighters, missiles etc) to deal with the 1IC by themselves in any case. So there wouldn't be a pressing need from the Chinese Air Force for a smaller 6th gen aircraft.

But given that the Chinese Navy will presumably develop a twin-engine 6th gen aircraft for carrier operations, it'll be straightforward to have an Air Force version as well. Like the current situation with the J-20 and J-35/J-31.

2. Looking at the geography, the US only has a handful of land bases which are at a 1500-3000km distance from China. So that helps inform the US requirement for 200 NGADs, capable of operating the 3000km distance from Guam to China.

In comparison, the Chinese Air Force have many more available bases, and a J-XD reaching 3000km can cover many additional operating areas beyond the Western Pacific eg. ASEAN and the Malacca Straits, Darwin in Australia, India, the Persian Gulf.

So my guess is that the J-XD will have a larger production run than the NGAD, which will help reduce costs.

 

[zeronet]

ASFAIK, the painter of this graph actually is the first guy releasing the 3-engine configuration for j-xd, so he deserves more credibility imo.

this belly bay configuration is close to what I am thinking j-xd should be given the information we have: 3-engine, side by side configuration with high tw ratio. This picture is definitely not j20 since no canards found. It is wide, with 8 missiles in major bay. I doubt there will be side bays considering he cannot describe it as exactly accurate as the real thing, so ignore the side bays. The width is definitely close to the reality because it’s a side by side configuration. The two intakes provide air flow to three engines, I believe they are on the side position just like the pic shows. I also don’t think the major bay is deeper than j20, to keep the cross section area appropriate for super cruise performance. But we have ucavs to carry the loads, that is the tradeoff to make, together with 3 engines already messing up the major bay

 

[Nx4eu]

View attachment 141227
ASFAIK, the painter of this graph actually is the first guy releasing the 3-engine configuration for j-xd, so he deserves more credibility imo.

this belly bay configuration is close to what I am thinking j-xd should be given the information we have: 3-engine, side by side configuration with high tw ratio. This picture is definitely not j20 since no canards found. It is wide, with 8 missiles in major bay. I doubt there will be side bays considering he cannot describe it as exactly accurate as the real thing, so ignore the side bays. The width is definitely close to the reality because it’s a side by side configuration. The two intakes provide air flow to three engines, I believe they are on the side position just like the pic shows. I also don’t think the major bay is deeper than j20, to keep the cross section area appropriate for super cruise performance. But we have ucavs to carry the loads, that is the tradeoff to make, together with 3 engines already messing up the major bay

And so some quick modifications later. Doesn't look too ugly now does it. Though I must admit, I do think my intakes are too small.

 

[latenlazy]

More conceptual research into 6th-gen configurations. Rear fuselage design for stable tail-less supersonic flight.

And so some quick modifications later. Doesn't look too ugly now does it. Though I must admit, I do think my intakes are too small.
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Was your modeling intentionally drawing from this earlier study or did you arrive at a similar planform accidentally?

 

[Blitzo]

And so some quick modifications later. Doesn't look too ugly now does it.
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Two intakes for three engines is also definitely viable (two main ducts, that each separate into a lateral primary duct that each feed their respective side engine, and a smaller medial secondary duct which joins with the other medial secondary duct that feeds into the central engine).

I also do think that side intakes makes more sense for this aircraft, which even if it is expected to be bigger than a traditional fighter aircraft, would probably still be expected to conduct some higher AoA maneuvers than a full pedigree bomber, so side or even ventral intakes probably makes more sense than dorsal intakes.


It would be neat if you could model what that airframe would look like with the V tails being able to fold down.

Nice job

 

[Nx4eu]

Was your modeling intentionally drawing from this earlier study or did you arrive at a similar planform accidentally?

No comment needed …

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For some reason, both

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and

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are quoting the post with above drawing without explicitly saying anything. They may be implying the 6th gen is using this triple engine design.

I used these drawings shown earlier

 

[Neurosmith]

A potential concern with a three-engine configuration would be the space allotted for the internal weapons bay. Single-engine fighters like the F-35 allows the bay to penetrate into the fuselage in the areas around the engine/inlets while twin-engine aircraft have a bay that occupy the space between the engines/inlets.

If a triple-engine design goes the "traditional route" but incorporating all engines/inlets entirely in the fuselage, it would need to go with a dual-inlet design in order to accommodate a sizeable weapons bay. Alternatively, if the third engine is a "special type", it could be mounted externally like the SR-72 so that it doesn't interfere with the weapons bay space.