Just nitpicking a bit, but I don’t think the canard is actually generating the inner vortex. That one is being generated from the LERX independently, though some downwash flow from the canards might be energizing those vortices further. The vortex outside of the LERX is being generated by the dogtooth that’s formed from the leading edge slat dropping. There is yet *another* vortex further out from the one formed by the dogtooth that starts closer to the tip of the wing which I think is eminating from the canard tip, and *that* one, I think, is the primary vortex the canard independently contributes. Also, while the two streams are definitely over both wings I’m not sure the one that’s less visible is less visible because of the lighting. It looks to me more like the asymmetry reflects actual differences in strength in the low pressure zones between the two sides, which could either be due to the airframe not being symmetrically level relative to the free stream or differences in deflection of control surfaces.
J-20 5th Gen Fighter Thread VI
- Thread starter siegecrossbow
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A small correction to my previous claims. If we stick with 40 cm maximum pacagable width of PL-15 missile, then 3 of such missiles, staggered, would take 1002mm in width, without any clearance. As well as 4300mm required for length, without any clearance.
Clearance observed in these recent images is 17 cm rear of the missile (missile end to rear wall of the bay) and 30-ish cm to the front wall of the bay.
Of course, clearance when packing 3 may be less. Much more so, to mere few cm. As is observed in F-22.
I measured F-22's bay and missiles. 3 amraams packed so their surfaces are touching, with no clearance, take 855mm in length and 4001mm in length. From what I can tell, they're packed in F-22 so so their fins aren't completely one in front of the others. Using same method as with J-20 to measure bay width, i get 1003mm wide bays (which may be wider than useful width but it's more fair since same method was used for J-20.
So 1003 minues 855 is 148mm. There are four points of clearance needed. For average clearance need of 37mm. As said, staggering is done so package length is less than 4001mm, but width is greater then. Still 2-3 cm of clearance per point is pretty much guaranteed.
Using the same 2-3 cm of clearance needed, four points of clearance needed would suggest 8-12 cm in total. To be added to 1002mm width needed by the 3-missile-package. For a total of 1010 to 1014 mm. Which is over the the width of the whole bay.
I am not saying 3 missiles can't possibly fit. There are a few caveats. Photo measurements can't be that precise. MM precision is out of the question, no matter if i use MM in my calcuations here. Error margin may be to a few cm. Which is actually inside the possible need to cram 3 missiles.
So why show 2 missiles in the unlikely case it can store 3? Perhaps it's maskirovka. Though, showing the belly with missiles inside it is counterproductive to such endavour, as it makes it easier for foreign services to asses the situation. Perhaps it's really elaborate maskirovka, though. With custom made dummy missiles for this occasion, with missiles made just a few cm larger than needed.
There's one issue that baffles me. PLAAF has the pl-12, which they're pretty happy with for most of their planes. They decide to make pl-15, but they retain the pl-12 body dimensions! (logistics issues ?) They make the fins slightly smaller though. Why even bother to make the fins smaller? When Amraam had its fins cut, it was done specifically for F-22 carriage. But for PLAAF, even though fins are changed, the missile still seems to be slightly too big. If it was too big by 10 cm, then fine. But it's too big only by a small, small fraction. So logic would dictate that the fin redesign MIGHT indeed have been made so missiles can fit inside j-20. Which would point towards photo measurement errors. Fins may have been made smaller for other reasons though. Perhaps the missile operates at higher speeds than pl-12. If so, smaller fins could make sense, providing similar performance. There's too many possibilities available, sadly.
Still, if i needed to asses the likelihood of outcome for the whole 2 or 3 missile deal, here's my opinion:
Chances of J-20 carrying 3 pl-12 per bay: Zero.
Chances of J-20 carrying 3 pl-15 variant with foldable wings: Almost non-existant. No one really does that.
Chances of J-20 carrying 3 pl-15 per bay: Small. As photo measurement could be wrong and logic of pl-15 variant even existing points to that possibility.
Chances of J-20 carrying 3 pl-xy per bay, hypothetical missiles tailor made for 3 pack: Small. Same as above.
Chances of J-20 carrying 2 pl-15 per bay and not carrying more within the next 10 years of service: over 50%.
Who is that Yankee guy talking about gun? What's his history of posting like, his previous credibility?
J-20 is almost certainly not using 1980s variant thrust level AL-31. It's using anything from FM1 variant thrust FM2 variant thrust. so possibly up to 140 kn.
could there be further domestic enhanced variant of AL-31? Possible. If that Yankee guy has great track record, maybe it really was done. Usually trading engine life for thrust can easily be made, as producers basically derate their engines from the max possible thrust by some small amount to maintain service life and then market the derated figure as the max figure. Whether that's fiscally or operationally wise, that's another matter.
Given that PL-12 has basically the same body (length/diameter) as PL-15, but with longer span fins and wings, it is basically impossible for J-20 to carry 3 pl-12 missiles.
I couldn't find any images (that weren't PS) of Su-57 with open bay. Do you have any? My claim was based on *potential* width and length, certainly. One that is assumed from the outer lines of the bomb bay doors. And one that is based on R-77-1, a smaller missile than PL-15. Suspension points were assumed to be arranged whichever way needed to maximize use of space. Anyway, the jury is still very much out on Su-57 until we get some actual images of its weapon bay. Preferably ones with R-77-1 missiles inside it.
Clearance observed in these recent images is 17 cm rear of the missile (missile end to rear wall of the bay) and 30-ish cm to the front wall of the bay.
Of course, clearance when packing 3 may be less. Much more so, to mere few cm. As is observed in F-22.
I measured F-22's bay and missiles. 3 amraams packed so their surfaces are touching, with no clearance, take 855mm in length and 4001mm in length. From what I can tell, they're packed in F-22 so so their fins aren't completely one in front of the others. Using same method as with J-20 to measure bay width, i get 1003mm wide bays (which may be wider than useful width but it's more fair since same method was used for J-20.
So 1003 minues 855 is 148mm. There are four points of clearance needed. For average clearance need of 37mm. As said, staggering is done so package length is less than 4001mm, but width is greater then. Still 2-3 cm of clearance per point is pretty much guaranteed.
Using the same 2-3 cm of clearance needed, four points of clearance needed would suggest 8-12 cm in total. To be added to 1002mm width needed by the 3-missile-package. For a total of 1010 to 1014 mm. Which is over the the width of the whole bay.
I am not saying 3 missiles can't possibly fit. There are a few caveats. Photo measurements can't be that precise. MM precision is out of the question, no matter if i use MM in my calcuations here. Error margin may be to a few cm. Which is actually inside the possible need to cram 3 missiles.
So why show 2 missiles in the unlikely case it can store 3? Perhaps it's maskirovka. Though, showing the belly with missiles inside it is counterproductive to such endavour, as it makes it easier for foreign services to asses the situation. Perhaps it's really elaborate maskirovka, though. With custom made dummy missiles for this occasion, with missiles made just a few cm larger than needed.
There's one issue that baffles me. PLAAF has the pl-12, which they're pretty happy with for most of their planes. They decide to make pl-15, but they retain the pl-12 body dimensions! (logistics issues ?) They make the fins slightly smaller though. Why even bother to make the fins smaller? When Amraam had its fins cut, it was done specifically for F-22 carriage. But for PLAAF, even though fins are changed, the missile still seems to be slightly too big. If it was too big by 10 cm, then fine. But it's too big only by a small, small fraction. So logic would dictate that the fin redesign MIGHT indeed have been made so missiles can fit inside j-20. Which would point towards photo measurement errors. Fins may have been made smaller for other reasons though. Perhaps the missile operates at higher speeds than pl-12. If so, smaller fins could make sense, providing similar performance. There's too many possibilities available, sadly.
Still, if i needed to asses the likelihood of outcome for the whole 2 or 3 missile deal, here's my opinion:
Chances of J-20 carrying 3 pl-12 per bay: Zero.
Chances of J-20 carrying 3 pl-15 variant with foldable wings: Almost non-existant. No one really does that.
Chances of J-20 carrying 3 pl-15 per bay: Small. As photo measurement could be wrong and logic of pl-15 variant even existing points to that possibility.
Chances of J-20 carrying 3 pl-xy per bay, hypothetical missiles tailor made for 3 pack: Small. Same as above.
Chances of J-20 carrying 2 pl-15 per bay and not carrying more within the next 10 years of service: over 50%.
Who is that Yankee guy talking about gun? What's his history of posting like, his previous credibility?
J-20 is almost certainly not using 1980s variant thrust level AL-31. It's using anything from FM1 variant thrust FM2 variant thrust. so possibly up to 140 kn.
could there be further domestic enhanced variant of AL-31? Possible. If that Yankee guy has great track record, maybe it really was done. Usually trading engine life for thrust can easily be made, as producers basically derate their engines from the max possible thrust by some small amount to maintain service life and then market the derated figure as the max figure. Whether that's fiscally or operationally wise, that's another matter.
Given that PL-12 has basically the same body (length/diameter) as PL-15, but with longer span fins and wings, it is basically impossible for J-20 to carry 3 pl-12 missiles.
I couldn't find any images (that weren't PS) of Su-57 with open bay. Do you have any? My claim was based on *potential* width and length, certainly. One that is assumed from the outer lines of the bomb bay doors. And one that is based on R-77-1, a smaller missile than PL-15. Suspension points were assumed to be arranged whichever way needed to maximize use of space. Anyway, the jury is still very much out on Su-57 until we get some actual images of its weapon bay. Preferably ones with R-77-1 missiles inside it.
Just for efficiencies sake, refer back to my reply to you back at Secret-Projects. I will say this though.
I think the chances of these two outcomes, simply depends on whether a new missile is in development to allow total carriage of 6.
At present there are rumours that such a weapon may be in the works, and if/when we get pictures of it then the likelihood will simply become 100%.
So what we should really be talking about here is what is the current likelihood of them developing a new BVRAAM in the near future, designed to allow carriage of 6 weapons.
From where I'm sitting I think the likelihood is better than good.
No one cropped fins just to fit more MRAAMs into a weapons bay until the F-22 and AIM-120D either. Modifying a missile to fit a specific carriage clearly isn't unprecedented. Whether it's by folding or cropping fins, or a new derivative missile, that the dimensions of the bay are already so close to fitting 6 missiles makes it a lot more likely that we will find 6 missiles in that weapons bay one way or another sooner or later, especially since missile designs *do* iterate pretty frequently and aren't just frozen after induction. I don't see the rationale behind not making modifications to fit 2 more missiles in the bay when clearly there are better space efficiencies and combat capabilities to be had from doing so.Totoro said:
I agree with totoro that the idea of a PL-15 variant with foldable wings is unlikely, because for some reason AAMs do not tend to have foldable wings. Who knows, the PLA might break this precedent, but for the sake of discussion let's not assume so.
However, I do believe that there is a high likelihood of a PL-15 variant with further reduced wingspan, or even reducing the overall diameter of the missile as well (which would essentially make it a new weapon altogether), to allow carriage of 6 BVRAAMs in total. It just makes too much sense to not use the extra effort to carry 6 weapons vs 4, which is a 50% increase in BVR payload.
If you tilt the middle missile by 45 degrees, you can trade more depth for width. I have no idea if it is feasible. But you can, in theory fit three missiles with overall width 100cm and 10cm clearance.
I think cropped fins is more likely than folded fins, but I would not rule either out.
EDIT: However which way they go about using that last bit of space to fit more missiles into that bay though, this discussion reminds me a lot of the double pylon debates we used to have about the J-10. Some of us thought it made too much sense for the J-10 not to adopt double pylons given its initially small load out, and lo and behold some years later double pylons are exactly what we saw.
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Do you guys know Yankee? Pretty credible "big shrimp" when it comes to Chinese military aviation. He and a group of "big shrimps" formed a little group and posts articles on WeChat following Chinese military developments. In a recent article he revealed several important and interesting points about the J20:
- The PL15 was developed roughly 8-10 years ago, and its current size, given 150KM range, is limited by China's technology back then.
- A new type of MRAAM is being developed and it won't be too long until the J20's main weapon bay can carry six of those MRAAMs. Until then, PLAAF will need to settle for 4 PL15s, at least there's missiles for use.
- On current J20s, there are no guns installed. However, gun posts are already there, they will be installed in the future.
- Observers can notice that J20's sound is different from Su27/Su30s in service at PLAAF. This is because the J20's engines, although still Russian origin, are improved using domestic technology, increasing its thrust. This cancelled out the negative effects brought about by weight increases going from prototype to its current state.
Yup, his post was linked to on a previous page, but it's good to bring it up again. He certainly is one of the most prominent big shrimps.
I think cropped fins and/or reduced diameter are very likely (potentially even a brand new missile), and folded fins is very unlikely.
Considering when PL-15 first emerged, and having entered service within the last two years, its development would've likely have begun 8-10 years ago as yankee says. At that time PL-12s were only starting to proliferate through the PLAAF in larger numbers as well and it was still not the standard BVRAAM (quite a lot of PL-11s still seen around).
Considering we are now at a similar stage for PL-15, and considering the PLAAF would've known quite a few years ago that only four PL-15s would've been carried by J-20, I expect development of a successor BVR missile to have begun somewhat earlier than the PL-15/PL-12 equivalent.
IMO the question we should consider is whether the new notional BVRAAM -- let's call it PL-XY for now -- will be merely a PL-15 with similar capability (range, seeker etc) but smaller to allow carriage of 6 in total which will likely allow faster development cycle to get into service quicker, or whether it will try to be more ambitious and incorporate other advancements (like dual ARH + ImIR guidance, or HTK) which will inevitably mean development will take longer.
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