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Bash the J-20 thread.

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....Not gonna lie, I just wanted to fit in. D:

 

But I'm sure Colli can find some things I guess, well, better then I could at least.

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2002 is a rather dated prototype.

 

Here's 2015, the confirmed latest. (It's speculated there's a 2016, but the few pictures I've seen of it appear shaky so I personally don't feel cool including it at the moment until I see more.)

 

j-20_2015_3.jpg?itok=CyfECe-9

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Yeah, if you decided to take a Tomcat, redesign it for stealth missions, remove the swing wings and make it land based, you'd.... basically have a J-20.

 

It's by the far the biggest of any 5th generation fighter seen so far that's in actually "seriously considerable" development stage.

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If this report is to be believed, the WS-15 engines that will eventually go in are lesser engines than the F119.  Yes; it's supposed to have more thrust than the F119, but the F119 uses square nozzles, and if it switched to round ones it would gain 10-15% more thrust.  Turbine inlet temperature is a bit lower (1447K vs 1649C, unless "K" was a typo and then the gap is much smaller, and I suspect this is the case) than the American products.

 

So American combat aircraft turbines still have a lead over Chinese and Russian products.

 

It's probably not as stealthy as an F-22 or JSF, but then nothing is.  The canards look like the biggest frontal quarter compromise to RCS, although they are planform-aligned and in the same plane as the wings (how well do they work as vortex generators then?).  Canopy isn't one-piece either, a flaw shared with the PAK-FA and YF-23.  Side-aspect looks pretty good; nice slab-sided, aligned fuselage surfaces just like a raptor.  Rear quarter is a bit of a mess with the conventional nozzles, ventral fins and what have you.  Again though, if you compare against the F-22, everything looks horrible in terms of rear-quarter stealth.

 

The Chinese aero engineers really love them some diverterless supersonic inlets.  Either their aerodynamicists are very clever, or their spies are.

 

It will be interesting to see how available these things are for export.

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If this report is to be believed, the WS-15 engines that will eventually go in are lesser engines than the F119.  Yes; it's supposed to have more thrust than the F119, but the F119 uses square nozzles, and if it switched to round ones it would gain 10-15% more thrust.  Turbine inlet temperature is a bit lower (1447K vs 1649C, unless "K" was a typo and then the gap is much smaller, and I suspect this is the case) than the American products.

 

So American combat aircraft turbines still have a lead over Chinese and Russian products.

 

It's probably not as stealthy as an F-22 or JSF, but then nothing is.  The canards look like the biggest frontal quarter compromise to RCS, although they are planform-aligned and in the same plane as the wings (how well do they work as vortex generators then?).  Canopy isn't one-piece either, a flaw shared with the PAK-FA and YF-23.  Side-aspect looks pretty good; nice slab-sided, aligned fuselage surfaces just like a raptor.  Rear quarter is a bit of a mess with the conventional nozzles, ventral fins and what have you.  Again though, if you compare against the F-22, everything looks horrible in terms of rear-quarter stealth.

 

The Chinese aero engineers really love them some diverterless supersonic inlets.  Either their aerodynamicists are very clever, or their spies are.

 

It will be interesting to see how available these things are for export.

 

For what it's worth, K does appear to be a typo, at least according to various defense boards that use C instead of K for the exact same turbine inlet temperature number that I checked after reading that. You're likely onto something.

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I think that in itself is a point of bashing, even if it's a relatively minor nitpick, even if we do correct the typo to 1447C and not Kelvins, We have yet to see the Improved WS-15 variant intended for the J-20 actually be used in a prototype yet, right now they're using AL-31Fs for testing, I want to see what it can really do with it's actual engines.

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There was a theory being passed around that the J-20 was basically a big stealth F-111-equivalent. Thoughts, folks?

 

I've heard it before but not quite sure I'm convinced yet just from a few things I've seen. Although the PLAAF does say It's going to be "Multi-Role", not sure bombing runs will be the primary focus.

 

1. the PL-12D missile, which is basically a rough equivalent to a Chinese AMRAAM, had a special variant made called the PL-12B, the only difference is that it has folding fins to fit into fighter bays with interal weapon storage, only 2 fighter or fighter-bomber aircraft have Internal storage in the PLAAF, the J-20 and J-31 (and I could go into another discussion about how alot of local defense experts doubt the PLAAF even intends to use the J-31 very heavily, if at all.) you can usually see these in official scale models and sometimes on the prototypes themselves when the bays are open. (It can carry up to 8 of them in the middle bay, there's 2-4 small outer internal bays that hold one PL-10 Short range air to air missile on the sides, the number depending on what prototype it is.) I guess as far as the multi role goes, we'll need to see exactly what they plan to be able to fit on it for things other then CAP missions.

 

2. This may not mean anything at all but from what I know, the production variants are supposed to have a 30x165mm cannon aswell with a ROF of around 2,100rpm supposedly, I don't think they'd plan for that for an F-111 style bomber. (while the F-111 had a weapons bay for an M61, memory serve me it was almost never actually fitted.) The JH-7 has a 23mm Gast cannon, but a pretty dated one with little ammo that's more for emergencies.

 

3. The PLAAF also has a stealth bomber project currently in the R&D phase known as the HX/H-20 project, and they also went out of their way to finish up the JH-7B program, which is far more then just a simple upgrade over the JH-7A but nearly a complete overhaul of the entire aircraft, and the JH-7 genuinely is known to be more of a bomber then a fighter despite the fighter-bomber tag attached to it.

 

I mean, I could be wrong and they might be planning it as sort of a fighter-bomber like the F-111 and the JH-7, but, I don't really see why at this point, counter theories are welcomes.

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DSI stands for Diverterless Supersonic Intake (or Inlet).

 

Jet engines are strange, magical devices that have strange, magical requirements.  One of the requirements is that the airflow feeding them can't be too turbulent, otherwise the compressor gets screwed up.  Different engines have different levels of resistance to turbulence; On the early F-14 and MiG-23 with TF-30 and R-35 engines respectively the resistance of the engines to turbulence was poor and both types were prone to compressor stalls.  On the MiG-29 and F/A-18 (with RD-33 and F404), resistance to compressor stalls is excellent.  Compressor stalls can be very bad; sometimes they even cause the engine to explode.

 

Turbulent airflow can be caused by a number of things.  Flying through the wake of another aircraft will cause the engines to ingest some turbulence, as will aggressive maneuvering.  A big selling point of Pugachev's cobra maneuver:

gFdsomv.gif

 

Was not that it had any combat utility, but that it proved that the latest generation of Sukhoi and MiG jets had engines that would not stall when handled roughly.

Another source of turbulent airflow is the fuselage of the aircraft itself.  A boundary layer of air builds up over the fuselage as the plane passes through the air.  Getting this into the engines would not be good.  So, most aircraft with fuselage-mounted air intakes have a gap between the fuselage and the intake itself so the engine isn't sucking in this badness:

 

b0XWAc4.jpg

But the F-35 JSF's intakes don't work like that.  The intakes are attached directly to the airframe with no gap:

 

aWug0wG.jpg



Somehow, those lumps in front of the intake deflect the boundary layer away from the intake:

5chou6r.jpg

This design is lighter and simpler, and Lockheed Martin claims that the better airflow allows the engine to generate slightly more thrust than a pitot inlet.  I suspect that the design is also easy to make stealthy.

Recently, Chinese fighters designers have started using similar air intake designs:

jf17_thunder_l7.jpg

No gap between the fuselage and intake, and a magical lump in front.

They've even retrofitted older designs with DSI.  Here's the J-10A:

J-10a_zhas.png

 

And now J-10B with DSI:

Chengdu-J-10B-Prototype-1031-1S.jpg

And of course J-20.

Very clever aerodynamicists, or very clever spies.

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I wonder how much of it is potentially knowing that it can be done and work well enough that there's a light at the end of the tunnel to get funding for that project.

 

Also, a bit from the wayback machine:

 

 


So American combat aircraft turbines still have a lead over Chinese and Russian products.

 

Everything I've heard is the US stuff is a bit ahead on performance, but it's maintainability and length between overhauls where they really shine.
 

 

There was a theory being passed around that the J-20 was basically a big stealth F-111-equivalent. Thoughts, folks?


Potentially, but I'm thinking about the Navy version. A big, long legged, and stealthy missile truck would be absolutely fantastic for a few things I can think might be well worth doing in a showdown with the US. It's looking to me like the stealthy high performance stuff is going to be force multipliers to corset more conventional fighters for a long while, and something you can get the whole production line of (or at least what's ready to fly) over the theater carrying a bunch of missiles is a heck of a problem against a force that's terrified their best fighters can't even carry enough missiles to prevent serious problems in case of an engagement. Something like that would be perfect for setting up hellish attrition rates on the desperately needed less stealthy planes and potentially the heavy and precious support planes. If it can beat an F-35 and tangle with the F-22 as a peer, even if it's a seriously disadvantaged peer, more the better.

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While I think it's certainly possible we can see Naval J-20 variants at some point, It's been highly suggested the first 24 production models are going to the PLAAF as opposed to the Navy air force.

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While I think it's certainly possible we can see Naval J-20 variants at some point, It's been highly suggested the first 24 production models are going to the PLAAF as opposed to the Navy air force.

 

Role and weapon fit wise, not specifics of operation and basing, I think it is likely to be a long range platform for a disturbingly large missile load.

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