Chengdu J-9 ... Shenyang J-11 to J-13 and other failed projects

[antonius123]

Why would Russia (Mikoyan) transfer "stealth technology" that they don't even have themselves??? Their SU-57 is definitely not stealthy ... and the Migs are even worse.

Even their Mig 1.44 is not stealthy either

 

[clarkgap]

Even their Mig 1.44 is not stealthy either

Seriously, Su-57 and J-20A both have some problems on stealth design. Su-57 has a terrible air inlet, and J-20A has too much airfoils. Why Chinese and Russian laugh each other on that?

 

[Deino]

Ok guys ... and after that long off-topic discussion on MiG 1.44, the PAK-FA and J-20 can we come back to the J-9 again please.

 

[gambit]

I had read your post in #36. I did not reply that because it was just ridiculous.

How was it 'ridiculous' ? I merely used Marty's own comparison method, which disqualified the J9/10 as potential origins for the J-20.

You ignore a long list of jet fighters used tailles delta layout include Rafale, Eurofighter Typhoon, JAS 39 Gripen, and J-10!

That is why I used the words 'influences like' with a few examples that spans manufacturers. There is no need to give the complete list. A few examples should be enough to give the readers -- including you -- that I am aware of that long list.

I believe everyone can find the obvious common features between J-10 and J-20. J-20 is basically a twin-engine J-10 with low RCS features. They both use the tailless delta-canard wing planform. Why do you think the designers of Chengdu would abandoned their experience on J-10 for a Mig prototype that they did not know anything?

Why do you guys keep avoiding using Marty's comparison method on the Chinese jets ? Because it would disqualify the Chinese sources as 'inspiration' or 'derived from'.

Note that you said: J-20 is basically a twin-engine J-10 with low RCS features.

Why not 'J-20 is basically a MIG 1.44 with low RCS features' ?

Why not BOTH ?

The J-9 never flew, but experience on that were transferred to the J-10. So why is it so improbable that Chengdu used the MIG 1.44 as 'inspiration' for the J-20 ? Because they never got their hands on the MIG ?

That last question has NEVER been a legitimate argument in engineering. NEVER. If you try to pull that argument -- even in an academic setting -- the prof would laugh you out of his class, let alone trying it in a roomful of working engineers, which am willing to bet none of you have ever been in that working environment.

When you see someone did something that worked, you do not need access to that something in order for you to try that design on your own project. The other guy already did much of the hard work of design form and demonstrator modeling. Access to his product would give accelerated progress to HIS design in your lab, but not necessarily to yours. However, if both his and your final goals are similar, if not outright identical, then using his design would give accelerated progress to yours.

https://www.defensetech.org/2011/08/19/did-the-j-20-come-from-this-mig/

...Russian defense sources are saying that design data and parts from the MiG 1.44 were indeed used in the design of the J-20.

...not clear whether such a transfer of technology had been legal.

You really think the few Americans on this forum are unique in believing that Chengdu got their mitts at least on those design data from the MIG 1.44 ? You are talking about speculations from technical experts, the kind that none of you Chinese on this forum knows about, from non-technical people but who specializes in reporting in the aviation fields, and from the gamut that ranges in between the two groups.

What kind of 'design data' ?

How about wind tunnel results that tells the differences between placements of the vertical stabs, for just one example ? In aerodynamics, the difference of a few mm can mean life or death, or a couple of degrees of angle-of-attack advantages, or a slimmer profile that can give the design a few extra knots of airspeed.

Data are much more easily transferable than the physical product. Forget parts. I want data, especially data that proved a design variant FAILED. I want failure data. Supposedly, Thomas Edison said he did not fail 1,000 times but found 999 ways that did not work. So if the other guy's data showed me that moving the vertical stabs 10 mm more outboards and angle it 5 deg less vertical to have a certain AOA achievement, why do I need access to his physical product ? I have the resources -- the wind tunnel -- to prove his failure and success data.

The J-9/10 do not have twin vertical stabs. The MIG 1.44 do. Low radar observable designs demands either no vertical stabs ( B-2 ) or twin canted ones. So if Chengdu have the design data for the MIG 1.44 with its twin vertical stabs, why should they used the J-9/10 as references ? The aerodynamics data for twin vertical stabs are there. All Chengdu had to do was test the slant degrees and move the stabs' location. We can get a little more in-depth by adding the vertical stabs' dimensions and shaping that would affect their locations and cant degrees, but the point is made: If Chengdu has the technical data for the MIG 1.44, why should they use the J-9/10 as references ?

The insistent demand that Chengdu MUST have physical access to the MIG 1.44 is absurd in the face of engineering experience that spans time and geography. Currently, I am in the semiconductor industry and is directly involved in Intel's new NVM technology that WILL displace NAND as the memory of choice. Prior to public release of the technology for review, which have been overwhelmingly favorable, we are more protective of data than we are of the product. Data of recipes and processing, of successful and failed variants of those recipes and processes, and from the data, the equipment used would be inferred, and everything would give our competitors 10 yrs of hard earned experience. Now that the product is out for review, Samsung and other competitors have bought it and deprocessed the product, but even so, we are still extremely protective of those data.

Of course Russia and China will deny any chance of data exchanged, legally or illegally. Unlike commercial products where I can sue my competitors if I can prove that they -- thru their deprocessing methods -- copied my product and used it in theirs, no country can sue other countries when it comes to military hardware. Who can enforce any judgement ? Chengdu is not going to admit to having the MIG's data. But we know better, do we ?

I also not said F-16 was the successor of Hawker P.1121.

You said -- that I said the F-15 and MIG-25 were 'successors' of the A-5, which I never used the word 'successor'. So when you brought on the F-16 and the Hawker P.1121, pretty much you implied the F-16 is such a 'successor'.

I know how USAF adjust their requirement on F-XX project. I just said "British Hawker P.1121 really looks similar like F-16. Base on your standard, it hinted at GD referenced it when they design F-16."

Fine, then apply that to the J-20 and the MIG 1.44. But if you do not agree, then you agree that the F-15SE did not came from the original F-15, correct ? Say it for the record.

Of course, the designer of J-20 need precendent.

Which is/are ? Remember Marty's post 33...

https://defence.pk/pdf/threads/chengdu-j-9.528464/page-3#post-10040971

If you insist that we disqualify the MIG 1.44, then you must disqualify ALL Chinese sources based upon Marty's method of comparison. But if you do so, then you must agree that the J-20 sprang from nothing, which no engineer would concur.

Marty -- not I -- put you in that bind.

 

[Figaro]

Seriously, Su-57 and J-20A both have some problems on stealth design. Su-57 has a terrible air inlet, and J-20A has too much airfoils. Why Chinese and Russian laugh each other on that?

Except Su-57 has many more problems ... in essence, it's mainly a flattened flanker. The designers definitely weren't going for stealth or failed miserably

 

[clarkgap]

I said this part is ridiculous:

For example...As we examine the J-20 wing design...

Of all the wing planforms available, why did Chengdu used the delta instead of rectangular or trapezoidal ? Because the world's best fighter aircrafts uses variations of the delta for its known advantages. That ruled out civil aviation as source for Chengdu's R/D plan, correct ?

How many of the world's best fighters uses tailless delta layout ? Did the SR-71 factored ? Not likely. That leave influences like the HAL Tejas, F-16XL, or Vulcan ( bomber ). And perhaps the MIG 1.44 ?

That the world was surprised by the J-20 allegedly a 'fifth-gen' fighter is definite proof that because of its mediocre history, Chengdu had to insert precedents into those process loops. Even though the J-20 have some differences from the 1.44, such as the reshaping and relocation of the intakes for the purpose of low radar observability, or that the airfoil of the J-20's delta wing is different than that of the 1.44's, there is no denying the overall physical commonalitiesbetween the J-20 and the 1.44. Saved a lot of development time and money.

In the West, aspiring aviation engineers are taught to look for precedents as much as possible, even to the point where the idea is printed into textbooks. You are saying Chengdu did not look for precedents in designing the J-20 ? What happened to the idea that 'we stand on the shoulders of giants' in order to innovate, invent, and produce anything ?

You have no problems boasting how copying and reverse engineering made China into the technological powerhouse she is today, from the cellphone to the supercomputer. But when it comes to the J-20...???

The final product that is the J-20 hints at what was inserted into its R/D development process loops: The MIG 1.44.

When an engineer want to design a new project, they commonly prefer to use their own experience first. You used the physical commonalities between the J-20 and the 1.44 to support your argument. I just figure out the physical commonalities exist among a long list of aircraft. And Chengdu had designed and produced one of them. You also told about twin vertical tails. However, J-20 has a pair of all moving vertical tails with completely different size, shape and angle. You said: "In aerodynamics, the difference of a few mm can mean life or death, or a couple of degrees of angle-of-attack advantages, or a slimmer profile that can give the design a few extra knots of airspeed." How could they used Mig-1.44's data on that? Even Iranian could developed a aircraft with canted vertial stabilizers base on F-5, did they got data from Mig-1.44?
You were using right theory to get wrong answer. I still do not understand how you get that:"The final product that is the J-20 hints at what was inserted into its R/D development process loops: The MIG 1.44."

PS. Why you wrote "developement" after "R/D"? Does the R/D means research and developement?

Fine, then apply that to the J-20 and the MIG 1.44. But if you do not agree, then you agree that the F-15SE did not came from the original F-15, correct ? Say it for the record.

So you think GD referenced the Hawker P.1121 when they design F-16? A-5 has a single vertial stablilizer, and Mig-25 has a pair of it. Base on your theory, F-15...?

PS. Reuter also said china steal design data of F-22 from Boeing. So which canted vertial stabilizers should Chengdu's engineer use?

Ok guys ... and after that long off-topic discussion on MiG 1.44, the PAK-FA and J-20 can we come back to the J-9 again please.

Sorry for my post, Deino. Doing the pointless discussion in J-9 thread is better than doing that in J-20 news & discussion threat.

 

[gambit]

You used the physical commonalities between the J-20 and the 1.44 to support your argument.

Do not worry about my argument, worry about your friend Marty's...

https://defence.pk/pdf/threads/chengdu-j-9.528464/page-3#post-10040971

The illogic is clear: Why is the MIG 1.44 is disqualified but not the J-9/10 ?

Why the double standards ?

According to Marty's methodology which is 1-1 matching of features, not a single jet can be used by Chengdu as a precedent. But then YOU conceded that...

https://defence.pk/pdf/threads/chengdu-j-9.528464/page-4#post-10055449

Of course, the designer of J-20 need precendent.

So which Chinese fighter did Chengdu used to help design the J-20 ? Based upon Marty's methodology, if not the MIG, then nothing else can. It is clear that Marty did not think his argument thru its consequences.

 

[antonius123]

Seriously, Su-57 and J-20A both have some problems on stealth design. Su-57 has a terrible air inlet, and J-20A has too much airfoils. Why Chinese and Russian laugh each other on that?

J-20 has a good frontal RCS which is comparable to F-22.

Problem with air intake of SU-57 will give much more impact on RCS compared to the airfoils of J-20A.

 

[clarkgap]

Do not worry about my argument, worry about your friend Marty's...

https://defence.pk/pdf/threads/chengdu-j-9.528464/page-3#post-10040971

The illogic is clear: Why is the MIG 1.44 is disqualified but not the J-9/10 ?

Why the double standards ?

According to Marty's methodology which is 1-1 matching of features, not a single jet can be used by Chengdu as a precedent. But then YOU conceded that...

https://defence.pk/pdf/threads/chengdu-j-9.528464/page-4#post-10055449


So which Chinese fighter did Chengdu used to help design the J-20 ? Based upon Marty's methodology, if not the MIG, then nothing else can. It is clear that Marty did not think his argument thru its consequences.

I had answer that. I post my points again:
1. There are a lot of aircrafts include Rafale, Eurofighter Typhoon, JAS 39 Gripen, and J-10 have common features with J-20. Chengdu designed and produced one of them.
2. All engineers would reference precedents for their work. But they commonly prefer to use their own experience first.
3. Why they did not use design data from Rafale and Eurofighter Typhoon for J-20? Some news claim a Greek hacker stolen data from Dassault and sold it to many countries include China. Others news claim Chinese hacker stolen data from BAE.
4. Reuter also said china steal design data of F-22 from Boeing. So which canted vertial stabilizers design should Chengdu's engineers choose?

PS. I never read Martin's answer before. Indeed, I commonly prefer to ignore all useless discussions about RCS of J-20 and the relationship between J-20 and Mig-1.44.

J-20 has a good frontal RCS which is comparable to F-22.

Problem with air intake of SU-57 will give much more impact on RCS compared to the airfoils of J-20A.

Chengdu's engineers used a set of methods to reduce the RCS of canards include adjusting the angle of them to avoid parallel and saw tooth structure covered by wave absorbing material. However, reducing is not elimination.

 

[Deino]

Pardon ... but what is this??? Only fan-art or a cancelled concept?

https://twitter.com/x/status/944717997733830656

 

[clarkgap]

Pardon ... but what is this??? Only fan-art or a cancelled concept?

https://twitter.com/x/status/944717997733830656

Fanart that combined by J-10 and Su-27.

 

[jkroo]

I said this part is ridiculous:


When an engineer want to design a new project, they commonly prefer to use their own experience first. You used the physical commonalities between the J-20 and the 1.44 to support your argument. I just figure out the physical commonalities exist among a long list of aircraft. And Chengdu had designed and produced one of them. You also told about twin vertical tails. However, J-20 has a pair of all moving vertical tails with completely different size, shape and angle. You said: "In aerodynamics, the difference of a few mm can mean life or death, or a couple of degrees of angle-of-attack advantages, or a slimmer profile that can give the design a few extra knots of airspeed." How could they used Mig-1.44's data on that? Even Iranian could developed a aircraft with canted vertial stabilizers base on F-5, did they got data from Mig-1.44?
You were using right theory to get wrong answer. I still do not understand how you get that:"The final product that is the J-20 hints at what was inserted into its R/D development process loops: The MIG 1.44."

PS. Why you wrote "developement" after "R/D"? Does the R/D means research and developement?



So you think GD referenced the Hawker P.1121 when they design F-16? A-5 has a single vertial stablilizer, and Mig-25 has a pair of it. Base on your theory, F-15...?

PS. Reuter also said china steal design data of F-22 from Boeing. So which canted vertial stabilizers should Chengdu's engineer use?



Sorry for my post, Deino. Doing the pointless discussion in J-9 thread is better than doing that in J-20 news & discussion threat.

Pls stop arguing with that guy, bro. Wiki contents filled in the page is pollution to the thread.
Thank you in advance.

 

[Figaro]

Pls stop arguing with that guy, bro. Wiki contents filled in the page is pollution to the thread.
Thank you in advance.

Gambit claims that the J-20 has a larger RCS signature than a 1974 F/A-18 ... nuff' said. You might as well argue against a brick wall instead

 

[Deino]

Fanart that combined by J-10 and Su-27.

Oh ... then sorry . But a handsome design IMO.

 

[clarkgap]

I found an interesting article about china's early research about 2-dimensional nizzle:

Images of Chinese 2-dimensional nizzle model from another article:

Moreover, according to following article, a 2-dimensional nizzle had been tested on a J-8, but I do not find their original source: