Chengdu J-20 5th Generation Aircraft News & Discussions

[gambit]

Are you still trolling this thread? Didn't I tell you that the canards were irrelevant to the J-20 Mighty Dragon's RCS profile?

You are a nobody and I will put my posts about this subject against yours, not what you copy/paste, any day.

The results from Australia Air Power's "Physical Optics simulation across nine radio-frequency bands" prove my point.

And they admitted the flaws of their own analysis.

Before you start disparaging Australia Air Power's Mr. Goon, you might want to look at his impressive credentials

Do not care. Goon is not above criticism, not even from anonymous critics. If anything, the official peer review process is quite anonymous. I guess you have never been through one.

 

[S10]

I guess the word 'deployed' must be very difficult to understand. And no, just because the US does not deploy such a design, that does not mean others could not. But it does begs the question of why the US does not.

Certainly, perhaps Americans consider their design to sufficiently meet requirement without canards. Is it required that everyone followed in US's steps without alternatives?

Does that mean the PLAAF's expectations were the same for US?

I don't know. Why don't you send an email to China's defence ministry, American DoD then compare.

 

[gambit]

Certainly, perhaps Americans consider their design to sufficiently meet requirement without canards. Is it required that everyone followed in US's steps without alternatives?

Let us take a review of the exchange, shall we...

One thing that confuses me are the canards. Other than the J-20, I haven't seen a single aircraft intended for stealth having canards. Not even the PAK-FA has them.

Beg to differ

Since you 'Beg to differ' then you presented a list of American EXPERIMENTAL designs but the question was about deployed designs, why are you avoiding supporting your arguments? Never mind that rhetorical question. I do not expect much from the Chinese boys on these matters.

I don't know. Why don't you send an email to China's defence ministry, American DoD then compare.

Then your argument about the PLAAF's satisfaction with the J-20's test results are meaningless in comparison to the F-22. Move along.

 

[S10]

Let us take a review of the exchange, shall we...


Since you 'Beg to differ' then you presented a list of American EXPERIMENTAL designs but the question was about deployed designs, why are you avoiding supporting your arguments? Never mind that rhetorical question. I do not expect much from the Chinese boys on these matters.

Did he mentioned American stealth planes in service or did he ask for canards on low observable designs? It seems you have a reading comprehension problem, and not a small one at that. However, given your history, I am not surprised.

Then your argument about the PLAAF's satisfaction with the J-20's test results are meaningless in comparison to the F-22. Move along.

Unless you want to imply that only Americans can set standard for low observable, it should be you that move along.

 

[gambit]

Did he mentioned American stealth planes in service or did he ask for canards on low observable designs? It seems you have a reading comprehension problem, and not a small one at that. However, given your history, I am not surprised.

Yes...He said: '...intended for stealth having canards...' Looks like YOU are the one with the reading comprehension problem. And by posting experimental designs to 'prove' your argument, good jumping to conclusion skill at that.

Unless you want to imply that only Americans can set standard for low observable, it should be you that move along.

Har...Absolutely I will move along. Nothing to see and learn from the conscript rejects.

 

[houshanghai]

indian had never taken USA figter in bid for MRCA .however they choiced to euro canard at last.
It is obvious that canard fighter is better than USA conventional fighter.

 

[S10]

Yes...He said: '...intended for stealth having canards...' Looks like YOU are the one with the reading comprehension problem. And by posting experimental designs to 'prove' your argument, good jumping to conclusion skill at that.

Unless you meant to tell me that NATF and X-36 had no requirement in low observable characteristics, you're just embarassing yourself. Or how about that SAAB design? Clearly "stealth" is written on it.

Har...Absolutely I will move along. Nothing to see and learn from the conscript rejects.

You're right, you'd definitely be a conscript reject had you been in China. They actually have reading comprehension exams. Run along now...

 

[Martian2]

You are a nobody and I will put my posts about this subject against yours, not what you copy/paste, any day.

And they admitted the flaws of their own analysis.

Do not care. Goon is not above criticism, not even from anonymous critics. If anything, the official peer review process is quite anonymous. I guess you have never been through one.

From Day One, you have been badmouthing the J-20 Mighty Dragon and playing up the Pak-Fa/T-50.

Expert analysis by Australia Air Power's Mr. Peter Goon has contradicted your misinformation and shown you to be a fraud. It's time to give up your charade.

I think everyone on this forum is getting tired of the misinformation spread by you and PtldM3 and your ridiculous excuses. The lack of analyzing backscatter is due to a limitation of available information, not a flaw in their analysis.

All planes have backscatter. Using common sense, we would expect the backscatter to be minor and not affect the overall standing of the world's three premier stealth fighters.

1. F-22
2. J-20
3. F-35

---------

Here is the bottom line from Australia Air Power's expert, Mr. Peter Goon:

"Engineers and Scientists who work in ‘stealth’ (AKA ‘Low Observable&#8217 designs have a way for explaining it to lay people: ‘Stealth’ is achieved by Shaping, Shaping, Shaping and Materials (Denys Overholser).

The F-22A is clearly well shaped for low observability above about 500 MHz, and from all important aspects. The J-20 has observed the ‘Shaping, Shaping, Shaping’ imperative, except for the axisymmetric nozzles, and some curvature of the sides that smears a strong, but very narrow specular return into something of a more observable fan. The X-35 mostly observed the ‘Shaping, Shaping, Shaping’ rule, but since then, to quote a colleague, ‘hideous lumps, bumps, humps and warts’ have appeared on the JSF to disrupt the shaping imperative, forcing excessive reliance on materials, which are at the rear-end of the path to ‘Low Observability’.

While discussing ‘rear-ends’, both the F-35 and the J-20 have large signature contributions from their jet nozzles. However, the difference is much like the proverbial ‘Ham Omelette’: the F-35 Pig is committed, but the J-20 Chicken is a participant. If the Chinese decide that rear sector Low Observability is tactically and strategically important, they are at the design stage where they can copy the F-22A nozzle design for the production configuration of the J-20."

----------

Try reading the complete paragraphs on backscatter:

What the Simulation Does Not Demonstrate

1- The simulator at this time does not model backscatter from edge diffraction effects, although the resulting error will be mitigated by the reality that in a mature production design these RCS contributions are reduced by edge treatments;

2- The simulator at this time does not model backscatter from surface travelling wave effects. In the forward and aft hemispheres these can be dominant scattering sources where specular contributions are low. The magnitude of these RCS contributions is reduced by edge treatments, lossy surface coatings, gap treatments, and panel serrations;

3- The simulator at this time does not model backscatter from the AESA bay in the passband of a bandpass radome, due to the absence of any data on the intended design of same, the resulting error will be mitigated by the reality that in a mature production design much effort will be expended in suppressing passband RCS contributions;

4- The simulator at this time does not model backscatter from the engine inlet tunnels or engine exhaust tailpipes, due to the absence of any data on the intended design of same. In the forward and aft hemispheres these can be dominant scattering sources where specular contributions are low. The magnitude of these RCS contributions is reduced by suppressing these RCS contributions with absorbers, and in the case of inlet tunnels, by introducing a serpentine geometry to increase the number of bounces;

5- The simulator at this time does not model structural mode RCS contributions from antenna and EO apertures, panel joins, panel and door gaps, fasteners and other minor contributors; although the resulting error will be mitigated by the reality that in a mature production design these RCS contributions are reduced by RCS reduction treatments.

The modeling software becomes less accurate on point #6. However, it is a far better estimate than someone pulling a number or conclusion out of thin air (like you know who). The modeling is still very useful, because an "underestimate backscatter in nulls" applies to all planes modeled.

6- The PO computational algorithm performs most accurately at broadside or near normal angles of incidence, with decreasing accuracy at increasingly shallow angles of incidence, reflecting the limitions of PO modelling. The simulator does not implement the Mitzner/Ufimtsev corrections for edge currents. While a number of test runs with basic shapes showed good agreement between the PO simulation and backscatter peaks in third party test sample measurements, even at incidence angles below 10°, characteristically PO will underestimate backscatter in nulls. This limitation must be considered when assessing results for the nose and tail aspects, where most specular RCS contributions arise at very shallow angles39.

When has the United States permitted independent third-party up-close testing of the F-22? However, that absurd requirement does not prevent me from agreeing that the F-22 is the current gold standard and superior to the J-20 in two important respects (e.g. J-20's minor side-curvature design flaw and round engine nozzles).

I suggest everyone ignore Gambit's absurd demand and acknowledge that the best available information and modeling clearly show the J-20 is currently inferior to the F-22, but superior to the F-35.

Importantly, even were the simulator capable of modelling shallow angle specular and non-specular RCS contributors, the PLA would not permit sufficiently detailed disclosures on the RCS reduction treatments applied to the airframe design, as a result of which reasonable assumed parameters would have to be applied instead of actual values.

 

[gambit]

From Day One, you have been badmouthing the J-20 Mighty Dragon and playing up the Pak-Fa/T-50.

Bunk...From day one, I have been advocating caution about making assumptions. Doubt is an important component of critical thinking skills. Something obviously the J-20 fanboys lack.

Expert analysis by Australia Air Power's Mr. Peter Goon has contradicted your misinformation and shown you to be a fraud. It's time to give up your charade.

I think everyone on this forum is getting tired of the misinformation spread by you and PtldM3 and your ridiculous excuses. The lack of analyzing backscatter is due to a limitation of available information, not a flaw in their analysis.

All planes have backscatter. Using common sense, we would expect the backscatter to be minor and not affect the overall standing of the world's three premier stealth fighters.

1. F-22
2. J-20
3. F-35

---------

Here is the bottom line from Australia Air Power's expert, Mr. Peter Goon:

"Engineers and Scientists who work in ‘stealth’ (AKA ‘Low Observable&#8217 designs have a way for explaining it to lay people: ‘Stealth’ is achieved by Shaping, Shaping, Shaping and Materials (Denys Overholser).

The F-22A is clearly well shaped for low observability above about 500 MHz, and from all important aspects. The J-20 has observed the ‘Shaping, Shaping, Shaping’ imperative, except for the axisymmetric nozzles, and some curvature of the sides that smears a strong, but very narrow specular return into something of a more observable fan. The X-35 mostly observed the ‘Shaping, Shaping, Shaping’ rule, but since then, to quote a colleague, ‘hideous lumps, bumps, humps and warts’ have appeared on the JSF to disrupt the shaping imperative, forcing excessive reliance on materials, which are at the rear-end of the path to ‘Low Observability’.

While discussing ‘rear-ends’, both the F-35 and the J-20 have large signature contributions from their jet nozzles. However, the difference is much like the proverbial ‘Ham Omelette’: the F-35 Pig is committed, but the J-20 Chicken is a participant. If the Chinese decide that rear sector Low Observability is tactically and strategically important, they are at the design stage where they can copy the F-22A nozzle design for the production configuration of the J-20."

----------

Try reading the complete paragraphs on backscatter:

I have done more than just read the complete paragraphs. I posted them and what I said is true: That the authors hope that production models will 'mitigate' or correct the flaws in their guesswork. While reasonable, it is absurd to expect us to take as gospel what is guessed in their work.

Here are the main points:

What the Simulation Does Not Demonstrate

1- The simulator at this time does not model backscatter from edge diffraction effects, although the resulting error will be mitigated by the reality that in a mature production design these RCS contributions are reduced by edge treatments;

2- The simulator at this time does not model backscatter from surface travelling wave effects. In the forward and aft hemispheres these can be dominant scattering sources where specular contributions are low. The magnitude of these RCS contributions is reduced by edge treatments, lossy surface coatings, gap treatments, and panel serrations;

3- The simulator at this time does not model backscatter from the AESA bay in the passband of a bandpass radome, due to the absence of any data on the intended design of same, the resulting error will be mitigated by the reality that in a mature production design much effort will be expended in suppressing passband RCS contributions;

4- The simulator at this time does not model backscatter from the engine inlet tunnels or engine exhaust tailpipes, due to the absence of any data on the intended design of same. In the forward and aft hemispheres these can be dominant scattering sources where specular contributions are low. The magnitude of these RCS contributions is reduced by suppressing these RCS contributions with absorbers, and in the case of inlet tunnels, by introducing a serpentine geometry to increase the number of bounces;

5- The simulator at this time does not model structural mode RCS contributions from antenna and EO apertures, panel joins, panel and door gaps, fasteners and other minor contributors; although the resulting error will be mitigated by the reality that in a mature production design these RCS contributions are reduced by RCS reduction treatments.

You are expecting us to take seriously a 'preliminary assessment' that DOES NOT contain data of the major causes of radiation coming off a body? Look at the highlighted and look at the illustration and see the obvious flaws.

The modeling software becomes less accurate on point #6. However, it is a far better estimate than someone pulling a number or conclusion out of thin air (like you know who). The modeling is still very useful, because an "underestimate backscatter in nulls" applies to all planes modeled.

Yes...The data on reflection is most accurate when the angle of incident is NORMAL.

6- The PO computational algorithm performs most accurately at broadside or near normal angles of incidence, with decreasing accuracy at increasingly shallow angles of incidence, reflecting the limitions of PO modelling.

The only time we can have that data is when the body is completely STATIONARY. Show me how does the J-20 remain stationary in mid-air so we can measure it under 'real world' environment conditions.

When has the United States permitted independent third-party up-close testing of the F-22? However, that absurd requirement does not prevent me from agreeing that the F-22 is the current gold standard and superior to the J-20 in two important respects (e.g. J-20's minor side-curvature design flaw and round engine nozzles).

I suggest everyone ignore Gambit's absurd demand and acknowledge that the best available information and modeling clearly show the J-20 is currently inferior to the F-22, but superior to the F-35.

Your suggestion relevant only for the Chinese members here who have put on their nationalistic blinders, not those who are willing to exercise critical thinking skills. I have no problems with APA's clearly stated 'preliminary assessment' with its flaws. But those who are willing to exercise critical thinking skills will have a problem with you demanding that they give such wide latitude for China.

 

[gambit]

Unless you meant to tell me that NATF and X-36 had no requirement in low observable characteristics, you're just embarassing yourself.

Are they DEPLOYED aircrafts?

Or how about that SAAB design? Clearly "stealth" is written on it.

Is it a USAF aircraft?

You're right, you'd definitely be a conscript reject had you been in China. They actually have reading comprehension exams. Run along now...

True...I would refuse to believe in 'Chinese physics' and would be expelled toot-sweet.

 

[peaceful]

The intake thing was explained many times. But it keeps coming back.

No one take this 2nd class toy seriously.

F-22 > J-20 > F-35 > T-50.

that is it.

btw, don't be too excited, it is a russia fighter anyway. please just recall what russian did to your aircraft deal?

 

[S10]

Are they DEPLOYED aircrafts?

Did he ask for deployed aircraft, or did he ask for aircraft intended to be low observable? Trying to twist his words won't save you.

Is it a USAF aircraft?

Did he mention USAF in his entire post? No? Well do stop embarassing yourself.

True...I would refuse to believe in 'Chinese physics' and would be expelled toot-sweet.

In order to learn "Chinese physics", you'd have to be at least somewhat capable of reading first. A trait you have not demonstrated.

 

[cn_habs]

How knowledgeable is gambit in physics anyway? I wonder if he actually understood what he's been talking about the whole time....as if he was an aerospace engineer.

 

[rcrmj]

How knowledgeable is gambit in physics anyway? I wonder if he actually understood what he's been talking the whole time.

dont worry he knows, if it is out of his understanding, he'd use the phrase like 'chinese physics' or 'you defy physics' sort of funny thing

 

[Render.Insane]

No one take this 2nd class toy seriously.

F-22 > J-20 > F-35 > T-50.

that is it.

btw, don't be too excited, it is a russia fighter anyway. please just recall what russian did to your aircraft deal?

f-35 was designed TO better than F-22, good going peacefull!!! to be cheaper, more tech savvy, and better capabilty in A2A combat!!! f-35 is number 1 hands down, F-22 is a failed project because it requires 30 hours of maintenance for every 1 hour of FLIGHT....

O didn't chninese just order 121 Al-31 engines from Russia, WOW so you really think China has over taken the might russia in aircraft dev???? Su-47 berkut used to send shivers down american defence, Russia claims T-50 was supposed to comebat and be better than f-22!
SO I AM SURE RUSSIANS have a rep to consider!

As for chinese, well i just bought an iphone 4 and also picked one off from the china town a replica ... Looks pretty decent from the outside BUT ITS NOT ORGINAL and it will probably break in few day! So now you tell me china has the ability to make knockoff of iphones , so it can now make better planes than Russians and Americans???? pride .... hahahahah see what it does to one