J-20... The New Generation Fighter III

latenlazy said:

Depends on what they're reporting. Peak power can be very unspecific.

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The video link is on tudou dot com (I can not post url)

Honestly it can not be accurate. Most likely the reporter gets the numbers from internet discussion forums.

"J-20 test flew 65 times in year 2011 ... two WS-10B engines. ... chinese made 100kw AESA radar... advanced fly-by-optics"

Bill's new article on J-20. Dr. Song's paper was mentioned.

siegecrossbow said:

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Bill's new article on J-20. Dr. Song's paper was mentioned.

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a good write by Mr. Sweetman

wonder if he reads SDF/CDF, many things in the article feel familiar, for me at least

paintgun said:

a good write by Mr. Sweetman

wonder if he reads SDF/CDF, many things in the article feel familiar, for me at least

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He visits secret projects and Deino is a mod there too so... yeah.

---------- Post added at 09:27 PM ---------- Previous post was at 09:27 PM ----------

paintgun said:

a good write by Mr. Sweetman

wonder if he reads SDF/CDF, many things in the article feel familiar, for me at least

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He visits secret projects and Deino is a mod there too so... yeah.

My vote is yes.

The technology only needs to match the APG-81. We know the APG-79 is peak 12 KW @ 2000 modules, and the APG-79 is already obsolete.

Peak power is not necessarily something difficult to do. The two limitations are the capacitors used to store and build-up energy for the pulses, and materials design that can sustain the peak power for the short bursts required for scanning.

Heterogeneous AESA arrays could provide the power needed to do so, you would have a block of modules specialized for high peak power at the cost of lower-resolution / poorer frequency-hopping, while at the same time you'd have more agile AESA modules optimized for greater resolution / frequency-hopping capability.

In a normal detection mode, both the peak and normal modules would hum at a low efficiency, but when high detection is necessary the peak modules are tasked to send pulses of high energy radio waves, every few seconds, before shutting down to cool off while the normal modules take over.

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As far as existing high peak power systems goes, the APG-81's output is classified, but we do have reports that its radar is powerful enough to jam or fry the APG-79 system used on the F-22. This suggests that for the Chinese to simply approximate the APG-81 system would make a 100 KW figure credible.

And beyond that, the 100 KW figure is likely to be merely a target. The WS-10 system was targeted at 132kn. From reports, we are getting 110kn on the active WS-10 systems. For the J-20 AESA to miss the target by a similar amount would mean that it would only reach 80 KW, and that kind of target is more easily believable.

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The end result is that on high-powered scan-mode, the J-20 would be able to detect an F-22 RCS target at 34 km. It may not be able to track the F-22 due to the heat difficulties of a high peak-power AESA, but it would be able to know that it's there. Against an AWACS opponent, it would be able to see the AWACS due to peak power far before the AWACS could detect it itself, due to the relative RCS difference between a non-stealthy AWACS and a J-20, then fire a PL-21 in its general vicinity and expect the PL-21's own targeting system to pick up the AWACS once in detection range, then expect the AWACS to be knocked out or at least an expensive fighter plane and well-trained fighter pilot to trade its life to save the AWACS.

siegecrossbow said:

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Bill's new article on J-20. Dr. Song's paper was mentioned.

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I'm surprised. Only facts are mentioned, with almost no speculation or opinion (for or against the J-20). It's a rare good quality article on Chinese military equipments.

Because almost all previous speculation and opinions have been proven wrong.

Actually I believe much of the speculation has been proven right, and to be very frank, much of the speculation would likely be sourced to the Plaaf, and flying it when sec def Gates was there is brilliant. Just playing devils advocate, but the JXX, come J-20 has some very strong design features of the Mig1.42-1.44, think and say what you want. All fifth gen aircraft share some striking simularities, an example being that Lock-Mart paid for the tech from the Yak-141, while they were developing the JSF. Bottom line is it really doesn't matter whether its original tech, or ya bought it or "borrowed it" from your friends, all these birds are related. Do a few more honest genetics studies, the J-20 is a very innovative and advanced aircraft. It has surprised only the people drinking the administrations kool-aid, and now they have quit selling that brand and owned up to the reality that the J-20 is the real deal, and she is, as I have said before the only real limitation is her powerplants, and you can bet that lots of time and money are being spent on that to bring her up to speed, literally and figurativly. IMHO

hmmwv said:

Because almost all previous speculation and opinions have been proven wrong.

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Exactly ! When j20 first show up all those China basher come out from the wood and give derisive comment the worst is Aboulafia I like this guy comment best . NOTAM did simulation on the J20 stealth characteristic and come to rebut his comment

Richard Aboulafia: (Washington Wire Blogs, 19th January, 2011, China’s J-20 Fighter: Stealthy or Just Stealthy-Looking?)

In an interview with The Wall Street Journal, Richard Aboulafia, an aviation analyst with the Teal Group, an aerospace and defense consulting firm, said China is still years away from perfecting stealth aircraft.

“It’s certainly stealthy-looking,” Mr. Aboulafia said. It looks like it’s got some of the faceting and some of the shaping that characterizes the front of the F-22, for example.

“But then you look the details and you realize this thing is just sort of cobbled together,” he added.

Take, for instance, the canard: forewings close to the nose of the aircraft that provide maneuverability. According to Mr. Aboulafia, “There’s no better way of guaranteeing a radar reflection and compromise of stealth” than adding canards to the aircraft.

“It’s quite possible that in 10 years they have a functioning equivalent of the F-22, but by then, the West will have moved on to something far more impressive,” he said.

Let’s put these august pontifications through the prism of the software simulator running the ‘Physical Optics’ specular reflection model of the J-20. Readers are encouraged to access and digest this analysis, but for the busy, here is the abstract verbatim:

This study has explored the specular Radar Cross Section of the Chengdu J-20 prototype aircraft shaping design.

Simulations using a Physical Optics simulation algorithm were performed for frequencies of 150 MHz, 600 MHz, 1.2 GHz, 3.0 GHz, 6.0 GHz, 8.0 GHz, 12.0 GHz, 16.0 GHz and 28 GHz without an absorbent coating, and for frequencies of 1.2 GHz, 3.0 GHz, 6.0 GHz, 8.0 GHz, 12.0 GHz, 16.0 GHz with an absorbent coating, covering all angular aspects of the airframe.

In addition, the performance of a range of Chinese developed radar absorbers was modelled, based on a reasonable survey of unclassified Chinese research publications in the area.

None of the surveyed materials were found to be suitable for use as impedance matched specular radar absorbers.

Modelling has determined, that if the production J-20 retains the axisymmetric nozzles and smoothly area ruled sides, the aircraft could at best deliver robust Very Low Observable performance in the nose aspect angular sector.

Conversely, if the production J-20 introduces a rectangular faceted nozzle design, and refinements to fuselage side shaping, the design would present very good potential for robust Very Low Observable performance in the S-band and above, for the nose and tail aspect angular sectors, with good performance in the beam aspect angular sector.

This study has therefore established through Physical Optics simulation across nine radio-frequency bands, that no fundamental obstacles exist in the shaping design of the J-20 prototype precluding its development into a genuine Very Low Observable design.

I agree completely that the J-20 has lots of potential, I think lots of the nay sayers do to, but they would like to pretend that the poor little JSF will be a contender, so they don't take any flak for pulling the plug on the real fifth gen by Lock Mart. It has taken us twenty years to get our fifth gen up and running, and to sell her down the river for an also ran, you have to say that the other guys are way behind. All these fifth gen birds are a handfull and take a lot of work and money, I'd rather pay now, than pay later. The J-20 is apparently a very nice flying aircraft with lots of growth potential, and as she starts to show the benefits of all the attention shes getting, I would hope some other folks sit up and take notice, I still think she's a good sized rigg and maybe thats an intentional decision based on her mission, just a thought. IMHO