Photos and analysis of China's J-20 fighter as it nears first flight

[kcran567]

This plane is not going to want to do much in-close dogfighting, it'll get carved up by a t-50 or f-22 in close.

So it can work long range I'll bet it has a 20% bigger AESA than any other 5th gen, even the T-50.

 

[saintkatanalegacy]

so you have decided that they already have a working AESA that's bigger albeit installed :

 

[ubiquitous08]

If we are talking anti-access which is a given, stealthy bvr missile firer makes sense. Targeting carriers etc in quick Lpi bursts then moving elsewhere and remaining compartatively undetected at high mach / altitude takes the whole lumbering T 95 Bear Carrier targeting mission into a whole new level; survivable by stealth and with the ability to defend itself from F18 E/Fs / F 35s whilst providing intermittent targeting updates for Df21D and or threatening ISR assets in theatre.

 

[kcran567]

so you have decided that they already have a working AESA that's bigger albeit installed :

They already have a smaller AESA in the J-10. The Chinese will have to put a larger AESA into that big airframe in order to make it viable for its role. I'd bet $5 on it being 20% bigger ;D

ubiquitous08 I agree...that is what this plane is being built for.

 

[flateric]

so you have decided that they already have a working AESA that's bigger albeit installed :

70092 reported back in 2008 that AESA is ready for J-20

 

[Dreamfighter]

This aircraft exhibits some of the philosophy that went into strategic interceptor projects during the closing stages of the USSR.
I won't be surprised if it has a high ceiling and decent range.

As far as the secondary ground attack role is concerned, I wonder if the canards can come into play there..

A very large, (not optimized for dogfighting) aircraft, long range interceptor to patrol those vast Chinese borders. And, to make up for their lack of a large Navy/Carrier presence, a strike role to attack ground and surface targets...I would suggest a very strong anti-carrier and anti-ship role for this big airplane. Possibly needs a large bay to be big enough to fit some very large solid rocket + ramjet powered anti ship missiles.

I agree with posts like this and Bobbymike's one.
Not being an aero-engineer or expert on aerodynimic configurations at all, I nevertheless have - from what I have seen sofar - the strong impression the J-20 is meant as a penetrating swing-role Mig-31/Su-34 combination, with good manoeuvering capability for such type of aircraft.

Frontal aspect stealth, supercruise speed (if it's engines are adequate/powerfull enough) and probably large weaponbays that can accomodate large (ramjet-powered) A2A-missiles or ASW-weapons...

Undetected supercruise BVR-interception of opposing air-assets, and undetected or (too)late detected fast strike to defeat air-defences.
At this moment, my opinion is that is the J-20 is - like DF-21 - mainly aimed at taking out carrier battle groups and their air wings... :-\

 

[Deino]

 

[Kovalchuk]

Some height comparison

 

[PAK FA]

Some height comparison

If we compare both design i think the T-50 is the best fighter in agility and supercruise, in stealth the J-20 might be at this moment slightly more stealthy.

The Russians have lots experience with canards and they did not use them on the PAK FA, the main reason is LEVCONs do the same, without the drag of canards, without killing lift to the wing as canards do.
Also the LEVCONS are at the same level of the wing and for stealth are better while doing the same canards do, creating a vortex and controling it, they also add lift ahead of the CG.

The J-20 needs to add a dihedral to its canards to reduce buffeting, also they are not above wing level where a canard works better in fact the J-20 needs a LERX for its wing, this is a result of the canard not inducing a vortex as it would if it was above wing level. The J-20 only has better rear nacelle faceting, but besides that it is a 1980s concept in wing configuration, the T-50 also shows better lateral stability, having no need of ventral fins.
The J-20 repeated the same F-22 boxy fuselage that adds less lift than the T-50 because it is not a integral configuration with fuselage wing blending that adds volume but gives lift
The LEVCON is better for stealth and aerodynamics than the J-20`s canards, so while the rear of the T-50 might be rounded the canard of the J-20 is worst than the T-50 LEVCON

 

[Husar]

70092 reported back in 2008 that AESA is ready for J-20

Who is 70092?

Sounds like some secret agent

 

[PAK FA]

PAK -FA,

the Su-30 MKI also uses canards for terrain following. But of course it is a multi-role plane.

Yeah but the Su-34 is really a striker, the Su-30MKI is a fighter going striker

Another thing i do not understand of the J-20 why reduce the size of vertical dorsal stabilizer fin but add a ventral fin? the F-22 has two large dorsal fins but the J-20 has four fins that in area are very close to the F-22 vertical dorsal fins` area
The T-50 has indeed smaller vertical stabilizers without need for a ventral fin.

The only explanation i have is they made the dorsal fins smaller to reduce vortex burst buffeting, since the ventral fins do not interact as the dorsal fins with the vortices shed by the canard and forebody chines, the ventral fins add more lateral control than bigger dorsal fins by their own would have.

 

[Matej]

Who is 70092?

Sounds like some secret agent

Member of the SinoDefence forum. He turned to be informed one.

 

[DFC]

PAK-FA,

of course the SU-34 is a striker.

that's exactly what I meant. in the sense that the MKI is a multi-role plane unlike the Su-34.

 

[PAK FA]

PAK-FA,

of course the SU-34 is a striker.

that's exactly what I meant. in the sense that the MKI is a multi-role plane unlike the Su-34.

no problem i understand you

 

[bobbymike]

So tying strategy and tactics from a future threat scenario. China sees the threat in a "Taiwan Invasion" situation as coming from only Taiwan itself, Guam and Naval Air from carriers.

Taiwan is being constantly bombed by China especially from its massive IRBM fleet (as Guam might be as well) Carriers are pushed far away from China due to the anti-carrier ballistic missiles (don't forget submarines as part of this). Japan and South Korea are not letting the US use its airspace (would Vietnam in such a scenario the hatred runs pretty deep?)

The only way the US can target mainland China is with its long range bomber fleet (only B-2s to start) B-1s and B-52s with conventional cruise missiles, air refueled F-22s, F-18s and F-15Es (?) and with its SSGNs? Carrier air and fighters from Guam need constant air refueling as close to China and possible while trying to keep these assets safe.

So China develops a semi-stealthy sircraft able to target these assets pushing the US farther and farther away from China hense greatly limiting US tactical air strike capability.

US response a new stealthy LR bomber, N-UCAVs and prompt global strike from CONUS plus hypersonic long range air and ship launched missiles (like the proposed modified Standard missile)

Just a thought experiment for the SP forum. Sorry if it is off topic.

 

[lastdingo]

Let's add that support assets like tankers and AEW could come under attack by long-range fighters with long-range missile and thus be pushed to greater distances as well.


Btw, I'm not sure that conventional missile warheads will do much lasting damage against a prepared airbase with repair teams. The missile cost may be prohibitive.

 

[Mike Pryce]

Btw, I'm not sure that conventional missile warheads will do much lasting damage against a prepared airbase with repair teams. The missile cost may be prohibitive.

RAND published a report on this in 2009:

http://www.rand.org/pubs/monographs/MG888.html

Indications were that missile strikes on airbases could sufficiently suppress ROC airpower, albeit temporarily, to allow PRC forces to gain air superiority and then to carry out conventional air attacks using PGMs. E.g from page 79 of the report;

"Although literally thousands of missiles might be needed to completely
and permanently shut down Taiwan’s air bases, about 60–200
submunition-equipped SRBMs aimed at operating surfaces would seem
to suffice to temporarily close most of Taiwan’s fighter bases. If China
can launch a single wave of this size, which seems consistent with the
number of SRBM launchers the PLA deploys, those missiles could suppress
ROCAF operations sufficiently to allow PLA Air Force (PLAAF)
strike aircraft to attack air bases and other military and industrial targets
with modern precision weapons. The result could be a Taiwan
with a profoundly reduced ability to defend itself, left open to a range
of follow-on actions intended to coerce or conquer it and its people."

How the J-20 might be used in such a situation is anyone's guess, but using it to keep US carrier airpower/AWACS etc. at arm's length is as likely as anything else I reckon. As is sending it to deal with F-22s where they are most vulnerable - on the ground.

It is interesting that the 'Taiwan scenario' can make the same case for STOVL as that made for it in the Cold War/NW Europe. If used in a scenario like that in the RAND report, STOVL aircraft could mean that many more missiles would be needed to adequately suppress ROC airpower, making a missile attack more difficult. However, to get the full benefits of a STOVL force you need to have an aircraft that can generate high sortie rates, which seems to be a challenge for the F-35B - ten vertical landings in ten months!

Anyway, the F-35B is not available to Taiwan, although I do know a bloke with some low time Harrier GR.9s to sell! Not that the UK would upset China in doing so. For an interesting article on all this see http://www.flightglobal.com/airspace/blogs/orion/archive/2010/06/04/taiwan-jump-jets.aspx which does note that "Countering such a tactic (STOVL dispersal) would require PLAAF strike fighters in the air over the probable target zone, and as long as the ROCAF is still in the fight, that will not be an easy task." Maybe the J-20 could be used in just such a 'strike fighter' role?

In summary - the J-20, if a strike aircraft, may well make STOVL an issue again, alongside China's SRBMs. It will be interesting to see how the F-35B story develops if the J-20 is a strike platform.

 

[sferrin]

The more I look at the J-20 and it's canopy in particular the more angry I get at our complete failure from the standpoint of security. China has been able to cart off information with impunity and it's like we don't even care. The list of almost carbon copies of equipment is longer than I care to recite.

 

[Sundog]

i think you're confusing weight with wing loading. Or you're trying to talk about wing loading in a round-a-bout way. The aircraft with lower wing loading will pull more g's, regardless of weight, all else being equal.

Let me explain when you have fighters of similar sizes and weights of course the aircraft with lower wing loading will have better turning ability that will happen even withing the performance of any fighter at different weights.
But heavy aircraft in example MiG-31, are only rated to 5Gs and even heavier aircrat like the Tu-160 are rated at 2Gs at most why?
Simple heavier the aircraft you have to multiply their weight by the Gs, this means a very heavy aircraft has loads that are stronger than a lighter aircraft.

This is more about size (side load!) than weight, and the use of a flat fuselage as with T-10 and T-50 reduces the problem a lot because the fuselage is strong and the span of the wings themselves doesn't need to be extraordinary.

Btw, the MiG-31 is a bomber interceptor based on another bomber interceptor design. The max load is in both cases small because there was no intent to ever do dogfighting with them. There was also no intent to dogfight with a Tu-160.
On the other hand, the F-15 was rated to 9 G while many smaller designs were rated to 7 G or less.


Modern combat aircraft can be developed to tolerate 11 or 12 G - the 9 G limit was used in the 70's because humans weren't able to go farther with pneumatic anti-g suits without lying or being in a water tank. The hydro-based Libelle anti-g suit has addressed this issue and allows for two more Gs. Future combat aircraft designs may very well be designed for 11 or 12 G - especially if they're meant to be optionally piloted.

I 100% agree with PAKFA, Lighter for a true fighter/dogfighter.

This aircraft J-20 is as big as an F-111 and being 60,0000 to 80,000 lbs range when fully loaded this is the largest of the new stealthy fighters by FAR.

Speculated that is a long range interceptor with some strike capability seems the most clear choice. It is clearly not built for dogfighting. And don't forget that unless the Chinese have built an engine that SURPASSES the ones in the t-50 or f-22, with higher thrust, how can the J-20 compete in the thrust/weight ratio category, let alone wing loading while having the largest design among them, and using (at best) engines with parity to the other designs. Even with engine parity to the f-22 and T-50, the J-20 will be heavier, and thus underpowered to the other two designs. Its a hard row to say the j-20 is going to be anything but a long range interceptor with strike capability, and air to air dogfighting given the least priority. The Chinese could have another (unbuilt) aircraft for that role, or just rely on the j-10's.

I was referring to actual aircraft design basics. I realize those don't tend to be popular among the believers.

BTW, how much better are the F-16 and the Gripen than the F-22 at dogfighting? Just curious. Enlighten me.

 

[sferrin]

BTW, how much better are the F-16 and the Gripen than the F-22 at dogfighting? Just curious. Enlighten me.

They're not. According to actual F-16 pilots (rather than internet ninjas) they get their asses handed to them regularly by the F-22 in dogfights.

 

[donnage99]

Some height comparison

Remember the height difference between average chinese men and russian men.

 

[saintkatanalegacy]

it's a 30 cm difference at best

but anyway, I have to disagree that it's not built with dogfighting in mind...

just by looking at the HUD, wing camber, vortex generators, dorsal fins and choice of canopy, you'll know that they thought about it

another thing that's often overlooked is synergy of the whole configuration...

heck, most people believe the YF-23 is strictly an interceptor... >.>

 

[Trident]

it's a 30 cm difference at best

At the absolute most! 4 to 5 inches is probably closer to the truth, the individual variation is probably much more significant.

 

[erkokite]

Btw, I'm not sure that conventional missile warheads will do much lasting damage against a prepared airbase with repair teams. The missile cost may be prohibitive.

RAND published a report on this in 2009:

http://www.rand.org/pubs/monographs/MG888.html

Indications were that missile strikes on airbases could sufficiently suppress ROC airpower, albeit temporarily, to allow PRC forces to gain air superiority and then to carry out conventional air attacks using PGMs. E.g from page 79 of the report;

"Although literally thousands of missiles might be needed to completely
and permanently shut down Taiwan’s air bases, about 60–200
submunition-equipped SRBMs aimed at operating surfaces would seem
to suffice to temporarily close most of Taiwan’s fighter bases. If China
can launch a single wave of this size, which seems consistent with the
number of SRBM launchers the PLA deploys, those missiles could suppress
ROCAF operations sufficiently to allow PLA Air Force (PLAAF)
strike aircraft to attack air bases and other military and industrial targets
with modern precision weapons. The result could be a Taiwan
with a profoundly reduced ability to defend itself, left open to a range
of follow-on actions intended to coerce or conquer it and its people."

How the J-20 might be used in such a situation is anyone's guess, but using it to keep US carrier airpower/AWACS etc. at arm's length is as likely as anything else I reckon. As is sending it to deal with F-22s where they are most vulnerable - on the ground.

It is interesting that the 'Taiwan scenario' can make the same case for STOVL as that made for it in the Cold War/NW Europe. If used in a scenario like that in the RAND report, STOVL aircraft could mean that many more missiles would be needed to adequately suppress ROC airpower, making a missile attack more difficult. However, to get the full benefits of a STOVL force you need to have an aircraft that can generate high sortie rates, which seems to be a challenge for the F-35B - ten vertical landings in ten months!

Anyway, the F-35B is not available to Taiwan, although I do know a bloke with some low time Harrier GR.9s to sell! Not that the UK would upset China in doing so. For an interesting article on all this see http://www.flightglobal.com/airspace/blogs/orion/archive/2010/06/04/taiwan-jump-jets.aspx which does note that "Countering such a tactic (STOVL dispersal) would require PLAAF strike fighters in the air over the probable target zone, and as long as the ROCAF is still in the fight, that will not be an easy task." Maybe the J-20 could be used in just such a 'strike fighter' role?

In summary - the J-20, if a strike aircraft, may well make STOVL an issue again, alongside China's SRBMs. It will be interesting to see how the F-35B story develops if the J-20 is a strike platform.

While not STOVL, perhaps the Gripen would make a good fighter for this role.

 

[Avimimus]

Another thing i do not understand of the J-20 why reduce the size of vertical dorsal stabilizer fin but add a ventral fin? the F-22 has two large dorsal fins but the J-20 has four fins that in area are very close to the F-22 vertical dorsal fins` area
The T-50 has indeed smaller vertical stabilizers without need for a ventral fin.

The only explanation i have is they made the dorsal fins smaller to reduce vortex burst buffeting, since the ventral fins do not interact as the dorsal fins with the vortices shed by the canard and forebody chines, the ventral fins add more lateral control than bigger dorsal fins by their own would have.

I might hazard a guess on this one (although we're all speculating far beyond the evidence in many areas):
The vertical stabilisers are relatively small and are also all-moving. It is possible that the ventral stabilisers will only be on the prototype (being deleted as the design is validated)

I was referring to actual aircraft design basics. I realize those don't tend to be popular among the believers.

BTW, how much better are the F-16 and the Gripen than the F-22 at dogfighting? Just curious. Enlighten me.

Hey, Sundog, are you baiting?

I'll bite: The F-22 likely has superior acceleration and also has 2d thrust vectoring. This means that it can follow-up its first pass almost immediately with a second one (in this sense its combat supermaneuvrability is superior than published Russian capabilities - assuming an effective targeting system eg. a lightweight helmet mounted sight). However, relying on thrust vectoring will bleed a lot of energy - so in a prolonged guns-only fight the other fighters might have a greater sustained turn.

 

[Avimimus]

I checked some more recent stats: The height difference is about 5cm. This might be a bit smaller if the people in the photos are from elite groups (as their families would be somewhat better fed than the average).

 

[flateric]

are you sure that better food goes into height, not into waist?
;D ;D ;D

 

[lastdingo]

BTW, how much better are the F-16 and the Gripen than the F-22 at dogfighting? Just curious. Enlighten me.

They're not. According to actual F-16 pilots (rather than internet ninjas) they get their asses handed to them regularly by the F-22 in dogfights.

As an economist I would ask for a dogfight comparison of several F-16's versus one F-22 of the same cost, but then again dogfight-only is unrealistic.

 

[sferrin]

BTW, how much better are the F-16 and the Gripen than the F-22 at dogfighting? Just curious. Enlighten me.

They're not. According to actual F-16 pilots (rather than internet ninjas) they get their asses handed to them regularly by the F-22 in dogfights.

As an economist I would ask for a dogfight comparison of several F-16's versus one F-22 of the same cost, but then again dogfight-only is unrealistic.

An intelligent economist would want the overall kill ratio.

 

[Husar]

Who is 70092?

Sounds like some secret agent

Member of the SinoDefence forum. He turned to be informed one.

Thanks.

Interesting read

China’s Aviation Sector: Building Toward World Class Capabilities
http://www.strategycenter.net/research/pubID.226/pub_detail.asp

 

[Mike Pryce]

Also interesting:

http://project2049.net/documents/aerospace_trends_asia_pacific_region_stokes_easton.pdf

Pages 17-18 (as marked on the pages, 20-21 to Acrobat) give some of the background developments against which the J-20 fits.

 

[PAK FA]

I was referring to actual aircraft design basics. I realize those don't tend to be popular among the believers.
BTW, how much better are the F-16 and the Gripen than the F-22 at dogfighting? Just curious. Enlighten me.

Sundog, let us see an aircraft as balance, in an balance you have to have equal weights to have it even, if you have different weights one of the arms will go up, unbalance, well a wing and a canard are the same, if you put the wing too aft, like in the case of the AJ-37, the nose weight will pitch down the Viggen automatically, now here we are talking about lift. instead of equal weight we are saying equal lifts, so the canard has to be made with enough lift to make the aircraft stable or instable, if the lift of the canard is positioned and sized in a way it only balances the aircraft, it will be neutral, if the lift of the canard is made small, it will remain stable, the aircraft will tend to pitch down, if it generates more lift it will pitch up and will become unstable.
Size and position matter, on the JAS-39, the wing has been moded forward compared to the AJ-37 Viggen, on the Eurofighter, the canards are moved way forward, this type of canard will generate less lift but can be made for pitch control, so it can reduce size, thus making less drag, this is good for supersonic speeds, but not as good for lift, the Rafale has a canard closer to the wing so it has more drag but more lift.

Now coming back to the J-20, its wings are well behind the mail wheels wells, so you can calculate it needs a big canard to generate enough lift to balance the aircraft, you could solve this in two ways one is a big canard or other is move the wing forward as in the case of the Gripen.
I am sure the J-20 is unstable, but unstability can be measure, depending in the FCS and positions of the canard and wings relatively with each other.
A Big canard also creates more drag this is not a thing you need, so moving the wing forward allows you to make smaller canards, and create better lift drag ratios, SAAB for that reason moved the wing forward from the Viggen to the Gripen
Now compare the J-20 to the Rafale once more, the Rafale has its main wheels closer to the middle of the wing chord than the J-20 it also has smaller canards

 

[overscan (PaulMM)]

I checked some more recent stats: The height difference is about 5cm. This might be a bit smaller if the people in the photos are from elite groups (as their families would be somewhat better fed than the average).

In fact, Northern China and Beijing in particular seemed full of rather tall people, especially the youth - old ladies still seemed pretty short on average.

As we went south people got shorter. In Guilin I felt pretty tall which is unusual for me at 5 ft 9 in

 

[quellish]

The more I look at the J-20 and it's canopy in particular the more angry I get at our complete failure from the standpoint of security. China has been able to cart off information with impunity and it's like we don't even care. The list of almost carbon copies of equipment is longer than I care to recite.

One of the things that J-20 highlights, however, is that carbon copying without a full understanding of the underlying principals behind something is counter productive. I can see several things that are evidence of this on the J-20.
A US VLO aircraft is the product of 50 years of research, development, testing, and experience. If you were to copy one or two aspects of a VLO/LO design or methodology, you would still not see the kinds of signature reductions that make VLO a game changer - because you do not have those decades of experience.

 

[PAK FA]

The vertical stabilisers are relatively small and are also all-moving. It is possible that the ventral stabilisers will only be on the prototype (being deleted as the design is validated)

Well to be honest, of all the designs i know and i can remember now that use ventral fins, JH-7, Su-24, MiG-21, F-14, J-8II, MiG-23, MiG-25, Su-27, MiG-29, sepecat Jaguar, Mitsubishi F1, J-10, Lavi and F-16.
None has done that except the Su-34 and MiG-29.
On early MiG-29s, the MiG-29 had ventral fins, later these were deleted when the fin extensions were fitted to carry chaff flare dispensers on the dorsal fins.
On the Su-34 were deleted because the aircraft is slower and not as agile as the Su-27.
The MiG-29 deleted the ventral fins just to increase the size of the dorsal fins,

So i do not think they will increase the size of the J-20 dorsal fin once they delete the ventral fins.
it is possible once they use 3D thrust vectoring they might delete the ventral fins, since 3D thrust vectoring allows for pitch and yaw control thus allowing for reducing the size of the aerodynamic controls such as vertical stabilizers.
But in my opinion that will depend if they ever make a good thrust vectoring nozzle and they settle for a round nozzle.
But i do not think without thrust vectoring the ventral fins will go

That is the reason the T-50 has such small vertical stabilizers, because it has 3D thrust vectoring with pitch and yaw control, the F-22 has only pitch thrust vectoring, so still its dorsal vertical stabilizers are quit big

 

[AeroFranz]

Just to clarify: fin distribution is just as important as fin area. The reason for lower fins is generally high alpha stability, as they are not blanketed by the fuselage - kind of the same reasoning why chin inlets are ideal for high aoa and dorsals are not. If you delete lower fins, it's probably because you don't care as much about high alpha. A secondary effect is the tailoring of the balance between dutch mode and spiral stability, although modern FCS make that less of a problem.

I have seldom seen airplanes that started out with more fin area than the eventual final configuration.

 

[saintkatanalegacy]

^exactly

 

[rousseau]

Now, to me, this J-20, is more like an experimental a/c rather than a prototype.
I heared that ventral fin will be removed on productive version and even with 4000*3000pix photo, we still didn't see side weapon bay presented.

 

[donnage99]

The more I look at the J-20 and it's canopy in particular the more angry I get at our complete failure from the standpoint of security. China has been able to cart off information with impunity and it's like we don't even care. The list of almost carbon copies of equipment is longer than I care to recite.

Our resources to counter chinese is paper thin due to the so called War on Terror effort. I remember n official complained that for every illegal transaction of classified technology from US to China, there are 12 others that go undetected.

 

[rousseau]

It has been proved the main wheel just is the wheel on Su-27, now everything goes to easy.
What a large weapon bay would be!

http://www.imgnets.com/viewer.php?id=76411176.jpg
The wing span is no less than MiG-31