Chengdu J-20 pictures, analysis and speculation Part II

[sferrin]

Maybe the central point is mean for one larger weapon at the expense of the two AAMs. Like the F-22 does when it swaps 3 AIM-120s for one JDAM.

 

[Deino]

My most favourite so far ...

 

[totoro]

I've forgot one more thing. While amraam has wings and fins of same span, pl-15 has shorter span wings. Seems to me like 27ish cm minimum width (38 cm wingspan). Different span of wings could allow pl-15, unlike amraam, to be staggered in such a fashion that distance from weapon bay wall to missile body is not the same as body to body distance. One could squeeze a few more centimeters from such an arrangement. Issue here, of course, would be length of the bay, as it needs to be at least 4,45 meters long for mid-body wings to fit. Such length is within possibility, though it's at the highest end of measurement estimates.

 

[VTOLicious]

My most favourite so far ...

Neat! Thx for sharing.

 

[Blitzo]

Maybe the central point is mean for one larger weapon at the expense of the two AAMs. Like the F-22 does when it swaps 3 AIM-120s for one JDAM.

I think F-22 swaps 2 AIM-120s for one JDAM?

Someone else on another forum thought on similar lines to you, but the idea that the side double/pair points could be points compatible with both launch rails for bombs or AAMs, and the middle single/pair points only compatible with AAMs, the idea being side double/pair points being more "robust" to allow them to carry a heavier load for a PGM as well as a lighter load like AAM, while the middle single/pair points being only rated for lighter loads like AAM.

I think there's credit to both that idea and your idea, the logic works both ways reasonably well unfortunately.

 

[CiTrus90]

Awsome pictures, thanks for sharing Deino

 

[gTg]

Maybe the central point is mean for one larger weapon at the expense of the two AAMs. Like the F-22 does when it swaps 3 AIM-120s for one JDAM.

I think F-22 swaps 2 AIM-120s for one JDAM?

Someone else on another forum thought on similar lines to you, but the idea that the side double/pair points could be points compatible with both launch rails for bombs or AAMs, and the middle single/pair points only compatible with AAMs, the idea being side double/pair points being more "robust" to allow them to carry a heavier load for a PGM as well as a lighter load like AAM, while the middle single/pair points being only rated for lighter loads like AAM.

I think there's credit to both that idea and your idea, the logic works both ways reasonably well unfortunately.

Does the PLAAF have an equivalent to SDB? If yes the second option would make sense.

 

[sferrin]

If they don't, they will.

 

[Blitzo]

Maybe the central point is mean for one larger weapon at the expense of the two AAMs. Like the F-22 does when it swaps 3 AIM-120s for one JDAM.

I think F-22 swaps 2 AIM-120s for one JDAM?

Someone else on another forum thought on similar lines to you, but the idea that the side double/pair points could be points compatible with both launch rails for bombs or AAMs, and the middle single/pair points only compatible with AAMs, the idea being side double/pair points being more "robust" to allow them to carry a heavier load for a PGM as well as a lighter load like AAM, while the middle single/pair points being only rated for lighter loads like AAM.

I think there's credit to both that idea and your idea, the logic works both ways reasonably well unfortunately.

Does the PLAAF have an equivalent to SDB? If yes the second option would make sense.

we've seen a few such weapons offered for export before at past defence expos, so the option is definitely there for the air force if they want it

 

[Blitzo]

One of my personal favourite angles of J-20 in flight from the last few days, one which I don't think we've been able to see enough of (or at all!) over the last few years given the high opsec...

 

[thefrecklepuny]

Actually looks like the ''MiG 31 Firefox''.

 

[sferrin]

My most favourite so far ...

 

[billybob]

It looks so much shorter in this view! Still very impressive though.

 

[FighterJock]

I like the look of the new J-20 camouflage scheme, much better than the previous all black scheme. B)

 

[Trident]

One of my personal favourite angles of J-20 in flight from the last few days, one which I don't think we've been able to see enough of (or at all!) over the last few years given the high opsec...

It would be excellent if it wasn't for the ventral strakes - now that the rest of the aircraft has been tidied up so nicely, they're the one remaining eye-sore IMHO. Kind of like training wheels on a professional racing bike.

Other than that, I've been thinking about the gun location proposed by Deino and although it seems like a logical position, I'm not entirely convinced. As the upper surface of the inlet does not slope downwards very strongly, I would have expected a bulge for the muzzle (think F-35A or T-50) or a much longer door hiding a trough (as on the F-22). Also, it would place the end of the barrel very close to the acutator/shaft for the canard (it looks as though the packaging problem would not be insurmountable, but certainly extremely challenging nonetheless).

OTOH, as others have pointed out, modern HOBS missiles and HMDs may finally have ushered in the era where a gun is no longer an absolute necessity (consider also the F-35B/C).

 

[VH]

But can J-20 super cruise? So far all we have seen J-20 do is engage in mild horizontal turns. Hopefully we will see a lively vertical performance at the upcoming airshow? That is if she has the engines for it.

 

[Blitzo]

It would be excellent if it wasn't for the ventral strakes - now that the rest of the aircraft has been tidied up so nicely, they're the one remaining eye-sore IMHO. Kind of like training wheels on a professional racing bike.

I kind of like the ventral strakes on the bottom; from the front it looks like an X-wing or one of those jets from ace combat, but maybe it's just me.

Other than that, I've been thinking about the gun location proposed by Deino and although it seems like a logical position, I'm not entirely convinced. As the upper surface of the inlet does not slope downwards very strongly, I would have expected a bulge for the muzzle (think F-35A or T-50) or a much longer door hiding a trough (as on the F-22). Also, it would place the end of the barrel very close to the acutator/shaft for the canard (it looks as though the packaging problem would not be insurmountable, but certainly extremely challenging nonetheless).

OTOH, as others have pointed out, modern HOBS missiles and HMDs may finally have ushered in the era where a gun is no longer an absolute necessity (consider also the F-35B/C).

I think there are too few stealth fighters in existence for us to actually make a judgement about what a "plausible" gun mount+panel should really look like. The F-35A and T-50 are one example with more obvious bulges, whereas F-22 has a much more subtle and difficult to ID mount that I'd hazard no one would be able to positively and confidently ID if they didn't already know where it was.

In J-20's case, I actually think the gun panel is probably here instead (different to Deino's location, but on the same side), and there is quite a dip from that position to the front of the intake for clearance, which is especially obvious from the front:

(my write up from about a year back on it http://plarealtalk.com/2015/12/22/j-20-gun-armament/)

 

[Blitzo]

But can J-20 super cruise? So far all we have seen J-20 do is engage in mild horizontal turns. Hopefully we will see a lively vertical performance at the upcoming airshow? That is if she has the engines for it.

I'm sure we will get this information all in due time.

Given Zhuhai will be J-20's first public outing and given this is the Chinese Air Force and their tendency to be low profile, I wouldn't be surprised if they just have J-20s take off, do a medium speed fly by, and land and not show off the plane in any sort of fancy way. Maybe the 2018 airshow instead.

 

[siegecrossbow]

But can J-20 super cruise? So far all we have seen J-20 do is engage in mild horizontal turns. Hopefully we will see a lively vertical performance at the upcoming airshow? That is if she has the engines for it.

https://www.youtube.com/watch?v=z68qRHAoAY4

0:27 - 0:39 in the second link.

 

[Trident]

I kind of like the ventral strakes on the bottom; from the front it looks like an X-wing or one of those jets from ace combat, but maybe it's just me.

Well, it's no use arguing personal tastes, so we'll just have to disagree

In J-20's case, I actually think the gun panel is probably here instead (different to Deino's location, but on the same side), and there is quite a dip from that position to the front of the intake for clearance, which is especially obvious from the front:

How would the projectile clear the airframe once fired from that location though? There is plenty of vertical separation between your proposed muzzle position and the upper inlet lip, but without a bump there needs to be "groove" through the airframe until the firing path clears the outer mold line, which would only happen substantially in front of that location. On the F-22 there is only a very subtle bump around the muzzle, but a pretty significant dent in front of it and a correspondingly long door covering a sufficiently large frontal projected area.

No such bump and/or dent is visible in your proposed gun position on the J-20 - IMHO, if it has a cannon it will indeed be fitted in the location Deino has suggested, where at least the upper surface of the inlet slopes down immediately in front (though again, it seems like a really tight job to me).

 

[Deino]

Two J-20As laded today at Foshan close to Zhuhai ....

 

[sferrin]

https://www.youtube.com/watch?v=z68qRHAoAY4

0:27 - 0:39 in the second link.

Yep. Somebody needs to get that spotter a 4k video camera.

 

[Blitzo]

Well, it's no use arguing personal tastes, so we'll just have to disagree


How would the projectile clear the airframe once fired from that location though? There is plenty of vertical separation between your proposed muzzle position and the upper inlet lip, but without a bump there needs to be "groove" through the airframe until the firing path clears the outer mold line, which would only happen substantially in front of that location. On the F-22 there is only a very subtle bump around the muzzle, but a pretty significant dent in front of it and a correspondingly long door covering a sufficiently large frontal projected area.

No such bump and/or dent is visible in your proposed gun position on the J-20 - IMHO, if it has a cannon it will indeed be fitted in the location Deino has suggested, where at least the upper surface of the inlet slopes down immediately in front (though again, it seems like a really tight job to me).

Why would there need to be a "groove" through the airframe for the firing path to clear? The firing path from that kind of muzzle position would still be able to clear the airframe quite safely from what I can see/imagine.

The firing path/clearance forward of the muzzle for my proposed location of the gun doesn't appear to have meaningfully less clearance than F-22's gun location IMO.

 

[Trident]

Why would there need to be a "groove" through the airframe for the firing path to clear? The firing path from that kind of muzzle position would still be able to clear the airframe quite safely from what I can see/imagine.

But that's just the point, the location is similar to the F-22's albeit with an even flatter upper surface, so there is if anything an even greater need for a groove/dent and yet there is no sign of one.

http://img32.mtime.cn/up/2012/11/07/043406.17987312_o.jpg

 

[Blitzo]

Why would there need to be a "groove" through the airframe for the firing path to clear? The firing path from that kind of muzzle position would still be able to clear the airframe quite safely from what I can see/imagine.

But that's just the point, the location is similar to the F-22's albeit with an even flatter upper surface, so there is if anything an even greater need for a groove/dent and yet there is no sign of one.

http://img32.mtime.cn/up/2012/11/07/043406.17987312_o.jpg

Is it flatter though? I think in the space anterior to the muzzle of the gunport for F-22 and the space anterior to my proposed gunport muzzle for the J-20 the fuselage is about similar.

The dent/groove on the F-22's gunport from what I see is at the same location as the gunport's panel/muzzle, rather than in front of the panel/muzzle. That suggests to me that the dent/groove upon the F-22's gunport's panel is unrelated to clearance anterior to the gun.

edit: if the F-22's dent/groove for its gunport extended forward to near the air intake before the fuselage there begins to slope downwards, then I think it would make sense to argue that such a thing would be expected for my proposed J-20 gunport as well. But the fact that F-22's dent/groove barely extends beyond the gunport's firing panel suggests to me it is unnecessary.

 

[Sundog]

Has it ever been officially stated that the J-20 has a gun?

 

[Blitzo]

Has it ever been officially stated that the J-20 has a gun?

I'm not sure if it's even been officially stated that the J-20 has a radar.

Relying on official statements at this stage of J-20's development/service to try and ascertain its characteristics or rule out characteristics is silly, as it would be for most other PLA projects.

If we're fortunate, we might get official specs and characteristics about the aircraft in four years or so, when it starts to enter service in greater numbers.

 

[kcran567]

If there is a gun the whole assembly will have to move up and down? The upper surface looks too flat for viable opening, even when compared to F-22.

 

[Trident]

The dent/groove on the F-22's gunport from what I see is at the same location as the gunport's panel/muzzle, rather than in front of the panel/muzzle. That suggests to me that the dent/groove upon the F-22's gunport's panel is unrelated to clearance anterior to the gun.

edit: if the F-22's dent/groove for its gunport extended forward to near the air intake before the fuselage there begins to slope downwards, then I think it would make sense to argue that such a thing would be expected for my proposed J-20 gunport as well. But the fact that F-22's dent/groove barely extends beyond the gunport's firing panel suggests to me it is unnecessary.

The actual muzzle is located at the very rear of the door, where the small bump is. So the dent does extend in front of the gun for the entire length of the door, and then some.

 

[Sundog]

Has it ever been officially stated that the J-20 has a gun?

I'm not sure if it's even been officially stated that the J-20 has a radar.

Relying on official statements at this stage of J-20's development/service to try and ascertain its characteristics or rule out characteristics is silly, as it would be for most other PLA projects.

If we're fortunate, we might get official specs and characteristics about the aircraft in four years or so, when it starts to enter service in greater numbers.

Don't be an ass, of course it has a RADAR as it has missiles. Either answer the question or not. It's obvious you don't know. That's what you should have started with.

 

[Blitzo]

Don't be an ass, of course it has a RADAR as it has missiles. Either answer the question or not. It's obvious you don't know. That's what you should have started with.

But your question wasn't asking whether we (or I) knew if it had a gun or not, but asking if anyone had officially said if it had a gun or not.

So my reply was to say that we typically do not get any official information about an aircraft's characteristics (or any other project) this early on, in other words, at this point it would be unreasonable to expect any sort of official information -- including official confirmation or denial of whether it had a gun or not... not to mention even information about its overall dimensions.

Your question shouldn't have been "Has it ever been officially stated that the J-20 has a gun?" but "Is it reasonable for us to expect official statements about J-20's characteristics?" Of course I was being facetious in my last reply, but your question was also a little bit presumptuous as well.

 

[Blitzo]

If there is a gun the whole assembly will have to move up and down? The upper surface looks too flat for viable opening, even when compared to F-22.

If there is a gun at that position, it would make little to no sense for it to have to move up and down -- I cannot think of any recent fighter that has had such a contraption for its cannon.

IMO, either that proposed location is the J-20's gun mount and it is able to work like F-22's and all the clearance and location are able to function, or it simply isn't the gun mount.

And it looks viable to me, from the front.

====

The actual muzzle is located at the very rear of the door, where the small bump is. So the dent does extend in front of the gun for the entire length of the door, and then some.

Okay, I think I see what you mean now in terms of grooves and dents.

I thought you were saying that the groove/dent needed to extend from the gun's muzzle all the way to the top of the engine inlet, which obviously isn't the case for either F-22 or J-20.

My reply in this case, is to ask why F-22 has a groove atop its gun door in the first place? Consider it -- if the gun door followed the same external shape of the fuselage on the shoulder -- but the gun remained in the same internal position and everything -- would the gun door still be able to fire with enough clearance? Of course it would. The change of the shoulder fuselage just changes the geometry of the gun door when and lifts the gun door panel upwards a few cm to be continuous with the fuselage, but it doesn't change the vertical clearance that the gun has to work with when the panel opens. That would be what I think J-20's gun door is like -- i.e.: it is simply continuous and smooth with the rest of the fuselage, and there is no reason to expect a groove at that location.
So that just leaves the groove/dent extending slightly in front of F-22's gun door, but again, why is that groove there? Is it there to provide an extra few cm of clearance, that the F-22's fuselage at that location is unable to provide, for only that 30cm or so in front of F-22's gun door? Well then, instead of simply assuming J-20 should also have a groove in front of its own gun door, wouldn't it make more sense to consider whether J-20's fuselage at that location may already provide that sufficient clearance or not?

The above couple of paragraphs is basically my round-about way of saying that if we really want to use something as subtle as a "groove" overlaying part of F-22's gun mount, then we should consider why that groove is there and whether it makes sense to expect J-20 to have it as well, or whether it could make sense for them to have a gun port without it.

And IMO, given the differences in the fuselage shape of both aircraft at the upper/shoulder locations, there is no reason for us to only consider the possibility of a gun mount on J-20 and having it be prerequisite on the presence of a groove.

 

[Trident]

I thought you were saying that the groove/dent needed to extend from the gun's muzzle all the way to the top of the engine inlet, which obviously isn't the case for either F-22 or J-20.

Nah, nowhere near that extreme of course, just far enough for the projectile path to pass clear of the outer mold line.

My reply in this case, is to ask why F-22 has a groove atop its gun door in the first place? Consider it -- if the gun door followed the same external shape of the fuselage on the shoulder -- but the gun remained in the same internal position and everything -- would the gun door still be able to fire with enough clearance? Of course it would. The change of the shoulder fuselage just changes the geometry of the gun door when and lifts the gun door panel upwards a few cm to be continuous with the fuselage, but it doesn't change the vertical clearance that the gun has to work with when the panel opens.

I don't think it would, the fact that the door is part of the dent is merely to ensure that there is no hard break in the surface that would pose RCS problems. Look at it as a more sophisticated, more smoothly shaped version of the Rafale's gun muzzle with its frangible cover:

http://cdn1-europe1.new2.ladmedia.fr/var/europe1/storage/images/europe1/economie/les-trois-premiers-rafale-ont-ete-livres-a-legypte-1369230/21295294-1-fre-FR/Les-trois-premiers-Rafale-ont-ete-livres-a-l-Egypte.jpg

http://www.superfighter.hu/RAFALE_2006KE/LIGHTSANTENNASPARTRAFALE2006INHUNGARY/photos/photo14.jpg

I mean, sand those edges down thoroughly and fit a permanent door and you'd get something a lot like the F-22's installation.

So that just leaves the groove/dent extending slightly in front of F-22's gun door, but again, why is that groove there? Is it there to provide an extra few cm of clearance, that the F-22's fuselage at that location is unable to provide, for only that 30cm or so in front of F-22's gun door? Well then, instead of simply assuming J-20 should also have a groove in front of its own gun door, wouldn't it make more sense to consider whether J-20's fuselage at that location may already provide that sufficient clearance or not?

Indeed, and to my eye, the J-20 fuselage has very little curvature in any direction at that location but instead looks like an almost entirely flat plane - so if anything, there would need to be an even more obvious dent, compared to the F-22. Or a much longer door hiding the entire thing (unlike the F-22), and there is no sign of either.

 

[icyplanetnhc (Steve)]

The reason for the F-22's fuselage having a slight depression in front of the gun muzzle is so that the muzzle cover door won't be excessively long, IIRC. By visual inspection, in the ports that you've highlighted, the J-20's fuselage doesn't appear to taper enough for there to be good clearance for the gun muzzle. The frontal profile picture you've given belies the J-20's longer fuselage, which I think would give a lower taper ratio compared to the F-22's. Even with taper, you may still need a slight depression like on the F-22 for the reasons given above. Of course, you can also work around that by giving the gun a great incidence angle with respect to the nose, but that may present an even more significant packaging problem. Currently I find it more likely that the J-20 doesn't have an internal gun.

Not only that, the value of an internal gun with the advent of HOBS missiles and HMD (and direct energy weapons currently under development, though it remains to be seen how the power requirements play out) has been called into question, and I wouldn't fault the Chinese for opting to forgo an internal gun. Just my opinion.

Speaking of which, but is the T-50 muzzle cover frangible or does it consist of a door? Based on my rough inspection from testing videos, there doesn't appear to be any kind of clearance or provision for a door mechanism.

 

[Trident]

Of course, you can also work around that by giving the gun a great incidence angle with respect to the nose, but that may present an even more significant packaging problem.

As the image posted by kcran567 shows, the F-22 gun is already set at a pretty substantial incidence angle - any more and you'd be in Schräge Musik territory (joking, of course, but strafing ground targets would probably become a problem because of the required steep dive angle).

Speaking of which, but is the T-50 muzzle cover frangible or does it consist of a door? Based on my rough inspection from testing videos, there doesn't appear to be any kind of clearance or provision for a door mechanism.

Not sure, it seems to be metallic on the flying prototypes but then we can't be sure they're actually fitted with a working gun installation. One fairly elegant possibility would be a rotary door (think Buccaneer bomb bay).

 

[Blitzo]

Nah, nowhere near that extreme of course, just far enough for the projectile path to pass clear of the outer mold line.

I don't think it would, the fact that the door is part of the dent is merely to ensure that there is no hard break in the surface that would pose RCS problems. Look at it as a more sophisticated, more smoothly shaped version of the Rafale's gun muzzle with its frangible cover:

http://cdn1-europe1.new2.ladmedia.fr/var/europe1/storage/images/europe1/economie/les-trois-premiers-rafale-ont-ete-livres-a-legypte-1369230/21295294-1-fre-FR/Les-trois-premiers-Rafale-ont-ete-livres-a-l-Egypte.jpg

http://www.superfighter.hu/RAFALE_2006KE/LIGHTSANTENNASPARTRAFALE2006INHUNGARY/photos/photo14.jpg

I mean, sand those edges down thoroughly and fit a permanent door and you'd get something a lot like the F-22's installation.

RCS control would make sense.

Indeed, and to my eye, the J-20 fuselage has very little curvature in any direction at that location but instead looks like an almost entirely flat plane - so if anything, there would need to be an even more obvious dent, compared to the F-22. Or a much longer door hiding the entire thing (unlike the F-22), and there is no sign of either.

I respectfully disagree, I think the position of the proposed gun door is at a position where the fuselage at that location begins to arc down anterior to it, and I think there is little to no need for a dent in front of the gun door.

Unfortunately it is difficult to truly compare the two without some accurate and representative 3D models.

 

[Blitzo]

The reason for the F-22's fuselage having a slight depression in front of the gun muzzle is so that the muzzle cover door won't be excessively long, IIRC. By visual inspection, in the ports that you've highlighted, the J-20's fuselage doesn't appear to taper enough for there to be good clearance for the gun muzzle. The frontal profile picture you've given belies the J-20's longer fuselage, which I think would give a lower taper ratio compared to the F-22's. Even with taper, you may still need a slight depression like on the F-22 for the reasons given above. Of course, you can also work around that by giving the gun a great incidence angle with respect to the nose, but that may present an even more significant packaging problem. Currently I find it more likely that the J-20 doesn't have an internal gun.

Not only that, the value of an internal gun with the advent of HOBS missiles and HMD (and direct energy weapons currently under development, though it remains to be seen how the power requirements play out) has been called into question, and I wouldn't fault the Chinese for opting to forgo an internal gun. Just my opinion.

I think it's definitely possible that J-20 does not have a gun, but considering the Chinese Air Force and Chinese military overall are quite conservative and considering that for most of their history they've never really had the benefit of reliable MR A2A missiles (until the last decade or more), I would be surprised if they were willing to forgo such a "traditional" weapon especially given the importance of it as a fallback, last ditch option, and on what is intended to be their premiere fighter aircraft for the next few decades as well.

That's why I'm willing to consider J-20 having a gun as more likely than not, at the current state of things where we have no official info about its gun status. It might turn out that J-20 does not have a gun, and if that does turn out to be the case I would be immensely surprised.

 

[Ian33]

A two barrel job, side by side laid flush and raised slightly. With today's computers and guided shells the extra degree or two isn't a problem.

 

[kcran567]

Of course, you can also work around that by giving the gun a great incidence angle with respect to the nose, but that may present an even more significant packaging problem.

As the image posted by kcran567 shows, the F-22 gun is already set at a pretty substantial incidence angle - any more and you'd be in Schräge Musik territory (joking, of course, but strafing ground targets would probably become a problem because of the required steep dive angle).

Speaking of which, but is the T-50 muzzle cover frangible or does it consist of a door? Based on my rough inspection from testing videos, there doesn't appear to be any kind of clearance or provision for a door mechanism.

Not sure, it seems to be metallic on the flying prototypes but then we can't be sure they're actually fitted with a working gun installation. One fairly elegant possibility would be a rotary door (think Buccaneer bomb bay).

Here's another one showing the firing angle, even so there is plenty of curvature on top surface of F-22 3-4 degrees more than J-20.

 

[sferrin]

A two barrel job, side by side laid flush and raised slightly. With today's computers and guided shells the extra degree or two isn't a problem.

I've not heard of anybody trying guided shells on an aircraft.