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Chengdu J-20 5th Generation Aircraft News & Discussions

The plane flew for the 30th time yesterday. It performed two rolls as well as many small diameter turns and "figure 8" turns. The bad news is that the security around the CAC was high since Biden visited Chengdu and Xi was there (he went over there to see the J-20 since it was convenient)? If people took photos/videos, they aren't releasing them yet.
 
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China's J-20 Mighty Dragon stealth fighter

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J-20 Mighty Dragon has no gaps between rear part of engines and fuselage. Notice the frameless one-piece bubble canopy. The continuous-curvature upper-body design of the J-20 is obvious to an untrained eye.

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Russian T-50 or Pak-Fa "stealth" fighter

Easy fixes

The first of many non-stealthy features, which are immediately noticeable about the Russian T-50, is the metal-framed cockpit canopy. Also, the protruding IRST probe in front of the cockpit needs to be recessed.

Medium fixes

Thirdly, the gaps between the engines need to be filled to eliminate a stronger radar echo. Fourthly, unlike the J-20, there is no RAM coating over the gleaming Russian T-50 engines on the entire exposed upper-body surface. The T-50 designers may have to resolve cooling issues with its engines if they are covered with RAM material.

Hard fix

The fifth problem with the top-side design of the T-50 is the lack of continuous-curvature. On the Chinese J-20, there is a nice round curve to the entire upper-body fuselage. On the Russian T-50, there are sharp and oblique angles, especially behind the cockpit. The Russians need to obtain a supercomputer and fix the design problem.

[Note: Thank you to "MwRYum" for the J-20 pictures and Aimarraul for the Russian T-50 pictures.]

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This is a clinical and objective post to contrast and compare stealth design features. This is not a "versus" comparison. If Sukhoi doesn't like what I'm pointing out, they should fix the problems.
 
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This is a clinical and objective post to contrast and compare stealth design features. This is not a "versus" comparison. If Sukhoi doesn't like what I'm pointing out, they should fix the problems.


I am pretty sure that a bunch of Sukhoi engineers know a lot more about plane design than you or I.

if they are happy with their product perhaps you should begin to think how this can work rather on how it can't ..
 
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A question to Chinese members:

JF-17 / FC-1 being on the same airfield where 2 of the Chinese future main fighters are being tested and with them FC-1 / JF-17 also flying & being tested doesn't sends a message that may be the CAF is looking into FC-1 as somewhat a future fighter at the low end side ??

Insights are welcomed as to me the 3 fighter jets being tested on the same facility may mean that they all are being looked as future fighter platforms.
 
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I am pretty sure that a bunch of Sukhoi engineers know a lot more about plane design than you or I.

if they are happy with their product perhaps you should begin to think how this can work rather on how it can't ..

The engineers may be good, but without the tools like super computing power, it is almost impossible to design an airframe that's both stealth and agile, otherwise you get some hideous look thing like the F-117.

There is the last list of top computers in the world (kindly tell me if you see Russia anywhere):

Rank Site Computer
1 RIKEN Advanced Institute for Computational Science (AICS)
Japan K computer, SPARC64 VIIIfx 2.0GHz, Tofu interconnect
Fujitsu
2 National Supercomputing Center in Tianjin
China Tianhe-1A - NUDT TH MPP, X5670 2.93Ghz 6C, NVIDIA GPU, FT-1000 8C
NUDT
3 DOE/SC/Oak Ridge National Laboratory
United States Jaguar - Cray XT5-HE Opteron 6-core 2.6 GHz
Cray Inc.
4 National Supercomputing Centre in Shenzhen (NSCS)
China Nebulae - Dawning TC3600 Blade, Intel X5650, NVidia Tesla C2050 GPU
Dawning
5 GSIC Center, Tokyo Institute of Technology
Japan TSUBAME 2.0 - HP ProLiant SL390s G7 Xeon 6C X5670, Nvidia GPU, Linux/Windows
NEC/HP
6 DOE/NNSA/LANL/SNL
United States Cielo - Cray XE6 8-core 2.4 GHz
Cray Inc.
7 NASA/Ames Research Center/NAS
United States Pleiades - SGI Altix ICE 8200EX/8400EX, Xeon HT QC 3.0/Xeon 5570/5670 2.93 Ghz, Infiniband
SGI
8 DOE/SC/LBNL/NERSC
United States Hopper - Cray XE6 12-core 2.1 GHz
Cray Inc.
9 Commissariat a l'Energie Atomique (CEA)
France Tera-100 - Bull bullx super-node S6010/S6030
Bull SA
10 DOE/NNSA/LANL
United States Roadrunner - BladeCenter QS22/LS21 Cluster, PowerXCell 8i 3.2 Ghz / Opteron DC 1.8 GHz, Voltaire Infiniband
 
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The engineers may be good, but without the tools like super computing power, it is almost impossible to design an airframe that's both stealth and agile, otherwise you get some hideous look thing like the F-117.

There is the last list of top computers in the world (kindly tell me if you see Russia anywhere):

Rank Site Computer
1 RIKEN Advanced Institute for Computational Science (AICS)
Japan K computer, SPARC64 VIIIfx 2.0GHz, Tofu interconnect
Fujitsu
2 National Supercomputing Center in Tianjin
China Tianhe-1A - NUDT TH MPP, X5670 2.93Ghz 6C, NVIDIA GPU, FT-1000 8C
NUDT
3 DOE/SC/Oak Ridge National Laboratory
United States Jaguar - Cray XT5-HE Opteron 6-core 2.6 GHz
Cray Inc.
4 National Supercomputing Centre in Shenzhen (NSCS)
China Nebulae - Dawning TC3600 Blade, Intel X5650, NVidia Tesla C2050 GPU
Dawning
5 GSIC Center, Tokyo Institute of Technology
Japan TSUBAME 2.0 - HP ProLiant SL390s G7 Xeon 6C X5670, Nvidia GPU, Linux/Windows
NEC/HP
6 DOE/NNSA/LANL/SNL
United States Cielo - Cray XE6 8-core 2.4 GHz
Cray Inc.
7 NASA/Ames Research Center/NAS
United States Pleiades - SGI Altix ICE 8200EX/8400EX, Xeon HT QC 3.0/Xeon 5570/5670 2.93 Ghz, Infiniband
SGI
8 DOE/SC/LBNL/NERSC
United States Hopper - Cray XE6 12-core 2.1 GHz
Cray Inc.
9 Commissariat a l'Energie Atomique (CEA)
France Tera-100 - Bull bullx super-node S6010/S6030
Bull SA
10 DOE/NNSA/LANL
United States Roadrunner - BladeCenter QS22/LS21 Cluster, PowerXCell 8i 3.2 Ghz / Opteron DC 1.8 GHz, Voltaire Infiniband

you can even build a supercomputer with a few hundreds of PS3s and anything with Nvidia Tesla..

you don't have to advertise it to the world, especially if it is not a money making machine like the rest on the list.
 
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China occupies the Nos. 2 and 4 spots on the Supercomputer Top Ten

It is not a coincidence that the world's top three supercomputing powers are Japan, China, and the United States. There is a strong correlation between the size of a country's economy (e.g. U.S., China, and Japan as world's top three) and its supercomputing power.

Race is on for new generation of supercomputer

"Race is on for new generation of supercomputer
Updated: 2011-08-20 07:52
By Chen Jia (China Daily)

BEIJING - Chinese scientists are charting a new roadmap for the country's independent research into building the fastest supercomputer in 2020.

"China is preparing to work on a supercomputer with a capacity of 100 petaflops by 2015 and try to produce the first exascale computer in 2020," said Hu Qingfeng, deputy chief designer of Tianhe-1A, one of the world's top 10 fastest supercomputers.

"We have kicked off the research of some core technologies and manpower cultivation for the plan," Hu, a professor at the National University of Defense Technology (NUDT), told China Daily.

Exascale computing is an attempt by scientists to take computing beyond the current petascale. If achieved, it will represent a thousandfold increase on that scale.

The challenges in core techniques include the performance of central processing unit (CPU), interconnection network, programming, energy management and system fault tolerance, he said.

Tianhe-1A was ranked No 1 in November last year by Top500, an organization that collates information on high-performance computing.

The capacity of Tianhe-1A is 2.57 petaflops, or 2.57 quadrillion calculations a second, which allows researchers to solve equations with far more variables, making results more accurate.

The challenges in developing supercomputers not only include technology breakthroughs, but also the promotion among users who usually prefer the old systems they are used to operating, said Lu Yutong, a professor at NUDT and a member of the Tianhe team.

"In a move to promote supercomputers' application among users, we need to better understand their practical demand," she said.

The application of Tianhe-1A has won positive feedback from about 100 users in fields such as seismic science, meteorology, medicine, commercial design, construction and manufacturing.

For example, Feoso Oil needs more than six months to get oil data analysis on a 10-square-kilometer piece of land with a depth of 5 km. However, after entering their equation into Tianhe-1A, the results come out in 16 hours, Hu said .

In 1978, then-Chinese leader Deng Xiaoping chose NUDT as one of the major institutions to develop China's own supercomputer. Five years later, the college produced its first supercomputer, Yinhe-I. It could perform 100 million calculations a second.

The next target for the Tianhe-1A team is to build a machine that can perform tens of petaflops per second, as well as developing new CPUs and graphics processing units (GPUs).

Although the supercomputer uses the 2048 FT-1000 CPUs developed by NUDT, it largely runs on the 14,336 CPUs made by Intel, the US chipmakers, and 7,186 GPUs from Nvidia, also based in the US."

[Note: Thank you to Conworldus for elucidating the world's top supercomputers and Grey Boy 2 for the newslink.]
 
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J-20 Mighty Dragon has no gaps between rear part of engines and fuselage. Notice the frameless one-piece bubble canopy. The continuous-curvature upper-body design of the J-20 is obvious to an untrained eye..



Absolutely ridiculous, a 'gap' is there, but it matters not. Having a tail boom between the engines has no adverse affects. In fact, it was put there to eliminate EM waves from bouncing back by incorporating a sharp point at the very rear.




Easy fixes

The first of many non-stealthy features, which are immediately noticeable about the Russian T-50, is the metal-framed cockpit canopy. Also, the protruding IRST probe in front of the cockpit needs to be recessed..




For the last time the metal has nothing to do with a canopy not being 'stealthy', it is the joints and the position of the joints. If the frame is horizontal to the receiver than there may be a problem. In the case of the pak-fa's frame is not horizontal. For real life references look at the F-117 and B-2 canopies and the positioning of their frames.




Hard fix

The fifth problem with the top-side design of the T-50 is the lack of continuous-curvature..




Continuous what? Why don’t you pull up a quote from a credible source describing this phenomenon, than explain how it works and what principles apply to this 'continuous curvature. I bet you can't, I have exposed you and other like you, when I ask for sources and explanation you chums crumble like a brick--at least know what you are talking about before you make claims.



On the Chinese J-20, there is a nice round curve to the entire upper-body fuselage. .




Jee and I though the entire purpose of reduced RCS was to have the smallest possible cross section, if we go by your logic, it is the J-20 that has the larger RCS since its 'round curve' traverses the entire fuselage while the pak-fa's 'round curve' fades into the fuselage, thus presenting less cross section.

Pay attention to the B-2's engines, they certainly have no 'continuous curvature'. Moreover, the B-2 has no one piece canopy yet somehow it RCS is in the class of the F-22, this gives us several theories to go off of, firstly the B-2 is not 'stealthy' or you are shamelessly making up facticuious claims--as usual.


On the Russian T-50, there are sharp and oblique angles, especially behind the cockpit. The Russians need to obtain a supercomputer and fix the design problem..




There are no angles of any kind behind the cockpit, and even if there was this proves what exactly? If you did your homework you would realize that every 'stealth' aircraft has a form of sharp angles to prevent EM energy from returning to the receiver--edge diffraction. The F-117 has a large point above the cockpit, other aircraft have sharp corners or sawtooth patterns on wings, bays, engines ect.

As for supercomputers Russia has plenty of them, if fact Russia even has supercomputers from the United States--IBM to be more specific. And realize what a computer does, a computer only does what it was programmed to do. The only advantage a computer has is that it does things quickly. A man with relevant experience in computers once told me that a computer is a fast idiot, and it is true it. People can do everything that a computer can do, but why should it matter when those so called supercomputers were used in the pak-fa's design?



This is a clinical and objective post to contrast and compare stealth design features. This is not a "versus" comparison. If Sukhoi doesn't like what I'm pointing out, they should fix the problems.


We all know your agenda. You have bashed the pak-fa countless times, you have even started threads about how poor the pak-fa's design is and how superior the J-20 is. No need no be a coward just admit it, you have an unhealthy obsession with the pak-fa and the J-20 gave you an ego ride.

Moreover, you have been calling everyone and anyone that has scrutinized the J-20 'trolls', so when you unfairly point out factitious 'flaws' it is being objective?
 
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A question to Chinese members:

JF-17 / FC-1 being on the same airfield where 2 of the Chinese future main fighters are being tested and with them FC-1 / JF-17 also flying & being tested doesn't sends a message that may be the CAF is looking into FC-1 as somewhat a future fighter at the low end side ??

Insights are welcomed as to me the 3 fighter jets being tested on the same facility may mean that they all are being looked as future fighter platforms.

Hard to say... I guess either the CAC is upgrading the JF-17 or perhaps the PLAAF expressed interest in procuring them as replacements for the J-7s. Really not sure at this point.
 
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J-20 Mighty Dragon has no gaps between rear part of engines and fuselage.
You mean a 'gap' between the engines? No matter what, such a 'gap' is irrelevant if the design take into consideration the edge diffraction effects coming off the structures that created said 'gap' and if the design direct those edge diffracted signals AWAY from source direction.

- An aircraft is a finite body.
- Impinging radar signals must leave this finite body somehow and sometime.
- Radar detection depends on the reception of these signals.

Therefore, the goal is (re)direct these signals away from source direction. No reception, no detection. Structural gaps exist? Meaningless if the seeking radar cannot pick up these signals.

The continuous-curvature upper-body design of the J-20 is obvious to an untrained eye.
You bandied this 'continuous-curvature' phrasing without a clue of what it mean. In fact, it is meaningless in your arguments. Yours, not mine.

surface_discont_diffract.jpg


The goal is not so much about incorporating curvatures into a complex body to control RCS. Yes, we moved away from the F-117's angled facetings to control RCS. Rather, the goal is to reduce SURFACE DISCONTINUITIES as illustrated above. I said 'reduce' because currently we cannot eliminate them. A complex body can have structural 'continuous curvatures' but if there are enough surface discontinuities on these structures, there will be enough edge diffracted signals to make detection possible. So if a region of a complex body has a relatively flat surface, the only time this 'flat plate' is detrimental to RCS control is if the impinging radar signal directly reflected off the surface, like a directly facing a mirror. But if the incident angle is less than 90 deg and approaches parallel, then the 'flat plate' is irrelevant and surface discontinuities gains relevance.
 
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27116804f457d4ff6cb1a44.jpg

China's J-20 Mighty Dragon stealth fighter

Zargl.jpg

J-20 Mighty Dragon has no gaps between rear part of engines and fuselage. Notice the frameless one-piece bubble canopy. The continuous-curvature upper-body design of the J-20 is obvious to an untrained eye.

The GAP can be seen clearly if you can't see ask some one around you to see that.

The first of many non-stealthy features, which are immediately noticeable about the Russian T-50, is the metal-framed cockpit canopy. Also, the protruding IRST probe in front of the cockpit needs to be recessed.

So what problem does the metal frame canopy has..... what does it has got to do with stealth ?? F-117 and B-2 have Metal framed canopies for cockpit what doe that has got to do any thing with stealth ??..... I guess glass bubble canopy was introduced in F-16 and F-22 for giving a clear view to the jock while flying in a dog fight. What kind of RCS would that small bubble produce have an to effect on the huge plane..... Its already as small as a cricket ball or little bit bigger than that so what kind of RCS it would add ??.....Even on that note AFAIK Sukhoi has been working on to get that thing hidden from radar waves.

Thirdly, the gaps between the engines need to be filled to eliminate a stronger radar echo. Fourthly, unlike the J-20, there is no RAM coating over the gleaming Russian T-50 engines on the entire exposed upper-body surface. The T-50 designers may have to resolve cooling issues with its engines if they are covered with RAM material.

The gaps have been left since it generates greater lift while super maneuverability and keeps the whole plane stable in such highly unstable maneuvers done at Supersonic speeds....... And what time would take it to paint them with RAMs.....They are currently testing the plane the strength of airframes etc... not creating a fancy show..... Is there some fancy party going on there in China where this poor ugly looking jet has to dress up and attend to.


The fifth problem with the top-side design of the T-50 is the lack of continuous-curvature. On the Chinese J-20, there is a nice round curve to the entire upper-body fuselage. On the Russian T-50, there are sharp and oblique angles, especially behind the cockpit. The Russians need to obtain a supercomputer and fix the design problem.

Which Stealth fighter has that continuous curve I didn't see that on F-22, F-117, F-35...... what that curve has to do with making a plane stealth..... the best thing such a curve can do is reflect back smaller wave length radar waves like X-band back to the receivers....... such a huge continuous curve works effectively only under longer wavelengths like L-band..... don't try to bring out your silly imaginary theories to create some BS excuse..... J-20 is a big fighter so it has curve to balance the plane there nothing it has to do with stealth..... even fan boys can say that round objects reflect more radar waves.


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This is a clinical and objective post to contrast and compare stealth design features. This is not a "versus" comparison. If Sukhoi doesn't like what I'm pointing out, they should fix the problems.

This nothing but some retard excuses presented by you against the available flaws in the J-20 design...... the two closely packed engines and that tail would make this plane highly unstable if it tries to perform some high speed maneuvers....... hence there is are huge canards to lessen that effect but that would still wear the airframe and control surface more quickly.

There is continuous curve is there since the plane is too big and heavy for those tiny engines which look like monsters even on huge flanker jets plus they are closely packed and does have the wing shaping to control the plane in a high speed turn hence the curve to and canards to make it possible that J-20 can turn.


P.S. Just a friendly question what are you and do you have any authority to question Sukhoi who are making plane even before PLA had farmers armed with sticks and spades as their National Soldiers......so have some damn respect about their authority and the ones who taught you so much...... I have heard they respect old and wise people there in China.
 
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A question to Chinese members:

JF-17 / FC-1 being on the same airfield where 2 of the Chinese future main fighters are being tested and with them FC-1 / JF-17 also flying & being tested doesn't sends a message that may be the CAF is looking into FC-1 as somewhat a future fighter at the low end side ??

Insights are welcomed as to me the 3 fighter jets being tested on the same facility may mean that they all are being looked as future fighter platforms.

I don't think the FC-1 being tested at the same field is necessarily a commitment by the PLAAF to induct the FC-1. I personally don't see a gap for the FC-1 to fill. There is no need to replace the J-7s because I think are pretty much going to be shifted over to the west for local air defence and be allowed to obsolesce there.
 
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J-20 Mighty Dragon and J-10B Vigorous Dragon together

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J-20 Mighty Dragon and J-10B prepared for another test flight.

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China's most-advanced J-20 stealth fighter parked next to pioneering J-10B with DSI.

[Note: Thank you to Martian and "cd nx1974nx" for the pictures.]
 
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