J-20 5th Generation Fighter VII

Eurofighter said:

And second, which is even more interesting, note the angle in the back of the weapons bay, which is sloped down and backwards, meaning that there is still additional space both in the vertical direction as well as to the back when the bay is fully closed.

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I don't understand this point, isn't the back white bit an overlap for the doors and bay to create a tight seal? Or are you speaking of something else. Can you draw out which section please.

I agree there is plenty of horizontal space, but the PL15 is so long I don't see how the fins would be offset

doublepostsorry

I have marked the area in question in the attached photo. What I mean is that the sloped angle at the back of the bay shows there is some vertical space left in the bay allowing two additional missiles to be sort of "stacked" below the existing 4 missiles. The problem is that is it hard to get a precise measurement of how much that additional space in the vertical direction actually is. But it is not a stretch to see that it is possible to utilize that additional space for more (or bigger) weapons.

Eurofighter said:

actually happy you brought up this photo. I agree that missile almost touch the bottom which makes it unlikely to make room for additional missiles by shifting to the fore or to the back.
However, first note that there is still plenty of room on the side and also in between the missiles. The still available room is actually quite specious, and like mentioned before, especially if you compare to the cramped up bay from F22.
And second, which is even more interesting, note the angle in the back of the weapons bay, which is sloped down and backwards, meaning that there is still additional space both in the vertical direction as well as to the back when the bay is fully closed. And that room could be sufficient to allow you to arrange additional missiles in a stacked fashion: one additional missile in each half of the bay, hanging slightly down from the middle and to the back compared to the current ones (also note that we have photos going around almost since the very beginning showing potential additional attachment points in the bay). But like I said, unfortunately the angle from where the photos is taken does not permit precision measurement of the vertical space, so it is really hard to be conclusive. But you got to admit there is something there isn't it?

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Well, for a country that's never seen large scale air to air combat except maybe very limitedly during the Korean war, I suspect that 4+2 set up is plenty in the minds of Chinese military doctrine.
If there's any space left, I suspect the priority would be given to the future increase in missile size for longer range AWACS killers.

byhyew said:

Well, for a country that's never seen large scale air to air combat except maybe very limitedly during the Korean war, I suspect that 4+2 set up is plenty in the minds of Chinese military doctrine.
If there's any space left, I suspect the priority would be given to the future increase in missile size for longer range AWACS killers.

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When was the last time anyone got involved in large scale modern air combat? DCS doesn't count

Eurofighter said:

I don't believe there is conclusive evidence (i.e. measurements with sufficient precision) that this is not possible even with current PL-15. Remember we have plenty of photos showing the weapons bay. But those photos are all taken directly from beneath, which means that the depth view of the bay is more or less distorted, so we are not able to fully access if the bay offer enough room for a "stacked" storage configuration for the missiles (like what you also see for F22). Also, if you look how cramped up the F22 weapons bay actually is compared to J-20's, but somehow still be able to fit six missiles. I bet if we see F22 with only 4 missiles in the bays, then it will also look like it wouldn't be able to fit six.

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Please not again this lame old discussion ! It has been proven more than once that under the current situation only four PL-15 fit into the bay but there is a new slightly slimmer AAM under development, maybe even test so that six can be held.

More missiles is always better if they don't come at great cost to performance. J-20 doesn't disappoint when it comes to missiles capacity. No doubt it is intended and probably does carry 6 MRAAMs and 2 SRAAMs. If drop-away pylons can be done, the J-20 can even consider carrying some wing mounted LRAAMs, to be fired and the underwing pylons discarded, long before the J-20 is effectively spotted and its stealth made useless afterwards.

The only modern PLAAF fighter that seems to be designed with the 4+2 layout is the J-10. It's A2A payload is 2 MRAAMs short in comparison to modern F-18s, F-16s, and Mig-29/35s. I don't understand why it appears CAC did not give those inner pylons AAM capability. The J-10 can perform inflight refuel and hold a fuel tank on its main centre fuselage pylon.

ougoah said:

More missiles is always better if they don't come at great cost to performance. J-20 doesn't disappoint when it comes to missiles capacity. No doubt it is intended and probably does carry 6 MRAAMs and 2 SRAAMs. If drop-away pylons can be done, the J-20 can even consider carrying some wing mounted LRAAMs, to be fired and the underwing pylons discarded, long before the J-20 is effectively spotted and its stealth made useless afterwards.

The only modern PLAAF fighter that seems to be designed with the 4+2 layout is the J-10. It's A2A payload is 2 MRAAMs short in comparison to modern F-18s, F-16s, and Mig-29/35s. I don't understand why it appears CAC did not give those inner pylons AAM capability. The J-10 can perform inflight refuel and hold a fuel tank on its main centre fuselage pylon.

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If you are in the middle of a flat desert with your enemy 100 yards away, would you pick a Colt-45 with 6-8 bullets or a sniper-rifle with a nice scope but only 4 rounds? Even if you have two other friends with their own shining Colt-45's, do you still like your chances against the sniper rifle?

quantity is important but missile quality is much more crucial. PL-15's diameter is bigger than AIM-120's thus giving J-20 a huge first-shooter advantage. as a pilot, it is a very worthy trade-off. when the AIM-260 JATM is in service, PL-15 probably can get a propellant upgrade and maintain its lead. the problem with both the F-22 and F-35 is that they were designed for 350 pound/7" diameter missiles. J-20's obviously good for 500-pound/8" missiles. 20 years from now, missiles will probably be offloaded to UCAV's anyway so internal space can be used for even greater range or more sensors/data links.

Eurofighter said:

I have marked the area in question in the attached photo. What I mean is that the sloped angle at the back of the bay shows there is some vertical space left in the bay allowing two additional missiles to be sort of "stacked" below the existing 4 missiles. The problem is that is it hard to get a precise measurement of how much that additional space in the vertical direction actually is. But it is not a stretch to see that it is possible to utilize that additional space for more (or bigger) weapons.

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That area can't be utilized for missile storage, the bay doors move through that area while they are opening. The designers of the J20 didn't just decide to section off a quarter of the weapons bay because they felt like it.

benny said:

I've done some editing. Thought I'd share what J-20 could look like in different forms
View attachment 63692
J-20 without canards

View attachment 63693
J-20 w/o canards and shortened fuselage

View attachment 63695
J-20 w/o vertical stab, canards and shortened. It looks like one of the 6th generation fighter concept envisioned a decade ago.

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Show me a version of the J-20 with canards, but without tailfins.



IMO, if a strike variant of the J-20 is desired, moving the engine off center as with the Su-57 is desirable.

There's roughly 8-10 meters available on the J-20 in length if a channel is placed between the engines. Making it 1.4 meters wide (or adding 700mm spacing), it could theoretically fit the DF-21D in terms of diameter, but not in length (would need 10.7 meters to squeeze it in). Making it 1 meter wide, it could fit the Kinzhal missile, making the J-20 an excellent striker.

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What's come up recently is that the NGAD has taken its first flight, and likely it'll be a tailfinless UHF-stealth optimized air superiority fighter / interceptor aimed at taking out Chinese AEW&C. This makes it even more imperative for the Chinese to continue to develop the J-20 platform.

A canard-ed tailless J-20, for instance, would be an excellent strike fighter, but to make it fully a UHF-stealth fighter both the tailfins and the canards would have to go.

But relying on TVC for pitch and yaw control would be quite a challenge. The advantage of the J-20's canards is that the canards make the development of the J-20 into a TVC-dependent fighter much easier; a strike variant wouldn't necessarily need the same hard maneuvering as a an air superiority variant so removing the tailfins would further decrease risk and allow experience in working a tailfinless TVC aircraft's aerodynamics.

Once the TVC has become fully mature, then the J-20 can evolve into a NGAD-like configuration, with neither tailfins nor canards and very strong UHF-stealth.

If Chinese engine thrust continues to increase, the interceptor version (i.e, the NGAD) with neither canards nor tailfins could be comparably maneuverable as the strike and dogfight versions.