J-20 5th Gen Fighter Thread V

[plawolf]

but aren't the ventral fins aligned with the contralateral fuselage and dorsal fin?
reflections from the ventral fins should go in the same direction as that from the contralateral fuselage?

and about the single flat surface, my impression is that it reflects radiation pretty well, just in an easier to control direction... you would still need to know the position of opposition radar emitters and receivers for you to achieve effective "stealth"

does the j20 ventral fin add an extra direction of radar reflection compared with its fuselage?

Great points.

But it's actually more than that. By canting the vertical stabiliser and ventral fins, what they hope to do is reflect as much as possible incoming radar energy onto the main wings rather than into a random direction so long as it's not right back at the radar emitter.

The main wing will absorb a great deal of he radar energy, and reflect what is left away from the waiting receiver.

That is why the non-canted vertical tails on the F22 and F35 are actually much more risky with ground based radars compared to the J20's canted ventricle fins.

With regards to the J20's ventrical fins aligning with the opposite fuselage, well that's an astute observation, but it's actually more complicated than just mere redirecting (which is what the F117 was all about, but again, I don't see the J20 bashing crowd picking any bones with the sheer number of surfaces and directions the F117 would have been reflecting radar energy in). Modern stealth fighters are only possible thanks to continuos curvature calculations the Russians foolishly published in open source internal science journals.

I would expect most of he J20 to use CC rules, so it's main fuselage may reflect very differently compared to a canted flat surface.

 

[zaphd]

There was an Aviation week article a few years back about the ATF program and it had comments from one of the designers who said the number of reflected directions doesn't matter that much, because the fighter is moving and the angle to ground based radars is changing, so that they only see occasional glints of the aircraft if the RCS peaks are kept narrow and isolated. He said he came to this realisation when driving and seeing the sun reflect off windows of houses he was passing by.

Now the exception is the front and rear aspects, because if the fighter is flying straight the angle to radars in those directions doesnt change.

Btw sorry for the eyeball rcs evaluation I did put an IMO as a disclaimer in it though.

 

[Blackstone]

Interesting take on the J-20.

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Even as

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[3], Beijing is continuing its efforts to acquire advanced Russian fighters.

Indeed, while a pair of J-20s garnered the attention of the world’s media, the Russian government quietly announced that it has started work on building 24 Sukhoi Su-35 Flanker-E fighters for the Chinese People’s Liberation Army Air Force (PLAAF). China signed a contract for the delivery of two-dozen Su-35s in November 2015 worth at least $2 billion.

“Delivery of these aircraft to China will be carried out under the terms defined by the relevant contract,” Vladimir Drozhzhov, deputy director of Russia’s Federal Service for Military-Technical Cooperation,

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[4] “We are now carrying out the execution of the first phase of our contractual obligations.”

As such, Russia is expected to deliver four Su-35s to the PLAAF before the end of the year. The remaining Su-35s are expected to be delivered within the next three years.

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[5], Moscow has insisted on agreements to secure Russian intellectual property onboard the Su-35. In previous years, the Chinese reverse engineered older versions of the Flanker into the Shenyang J-11, J-15 and J-16 series of aircraft.

“We established a Russian-Chinese working group for the purposes of practical implementation of this agreement, which held a regular meeting in September this year,” Drozhzhov said.

Despite whatever agreement Beijing might have signed with Moscow, the Chinese are almost certainly interested in the Su-35 to harvest its technology. While the current configuration of the J-20 externally resembles a genuine fifth-generation fighter in several respects, China remains woefully lacking in engine and mission systems avionics technology. The Su-35’s Saturn AL-41F1S afterburning turbofans, Tikhomirov NIIP Irbis-E phased array radar and electronic warfare suite are likely of high interest to Beijing.

Indeed, China has not perfected its indigenous WS-10 for its Flanker clones, let alone come close to finishing development of the next-generation WS-15 it would need for the J-20. The WS-15 is currently thought to be in a ground-testing phase with flight trials set to begin on an Ilyushin Il-76 some time in the future.

In fact, China has not demonstrated it can build any reliable jet engine—and that’s including designs that it basically stole from Russia. Indeed, the J-20 currently appears to be powered by twin

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[6] AL-31F engines found on the Sukhoi Su-27 and its many Chinese knockoffs. The addition of the Russian-built AL-41F1S series engines might provide a solution to Beijing’s engine woes.

There are indications that the J-20 carries an

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[7] (AESA). Allegedly, the J-20 would be fitted with a Type 1475 (also referred to as the KLJ-5 radar), which is supposedly being tested on a China Test Flight Establishment owned Tupolev Tu-204. However, there is no way to confirm that information because the PLAAF isn’t all that forthcoming about sharing information concerning its developmental projects. However, Russian radar technology is generally believed to be ahead of China’s and it is certainly possible Beijing could glean valuable technical insights from the Irbis-E.

The one advantage the Chinese have over the Russians is in the realm of electro-optical/infrared targeting systems—where Moscow has lagged behind in the wake of the post-Soviet economic meltdown of the 1990s. Indeed, the J-20 does appear to have an electro-optical targeting system (EOTS) mounted under the nose—which could be the Beijing A-Star Science and Technology

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[8]. But there is no publicly (and reliable) data available about the performance of that sensor. It is very likely it does not match the performance of American or Israeli systems.

Certainly, the J-20 does represent a leap forward for the Chinese defense-aerospace industry. One day, China will be able to develop and build its own jet engines as well as create world-class mission systems avionics—especially given the investment Beijing continues to make into the defense-aerospace sector. However, that day is not today. If the J-20 was really as capable as some would have you believe, Beijing wouldn’t bother with buying a token fleet of Su-35s—there would simply be no point in doing so.

 

[jobjed]

Interesting take on the J-20.

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@Deino's theory is that the PLAAF wants to practise using TVC, and practise fighting against aircraft with TVC. Adding onto his theory, I'd say the 24 Su-35s will go to a dedicated OPFOR regiment, sort of like an aerial version of the 195th dedicated OPFOR brigade for the ground forces.

 

[Hendrik_2000]

As soon as I read the author is Dave Majumdar I stop reading it . A lot of factual error and hearsay. National Interest a propaganda magazine

 

[latenlazy]

Interesting take on the J-20.

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As an American, I would caution that this proclivity to downplay, underestimate, and assume the worst of China's military technological abilities is going to bite us in the behind one of these days.

 

[weig2000]

As soon as I read the author is Dave Majumdar I stop reading it . A lot of factual error and hearsay. National Interest a propaganda magazine

If I remember correctly, this is the guy who claimed that India has an edge over China when it comes to build aircraft carrier, because India possesses some "indigenous Indian alloy" that China has difficulty matching.

That China is behind Russia in mission avionics and phased array radar is just another of the author's creation/imagination. The radar on J-20 is at least China' second-generation AESA radar, and to imply that China is trying to copy Irbis-E, a PESA radar is just ludicrous.

China's interest in Su-35, IMO, is simply to learn how Russia has evolved the Flanker lines, since China has a large inventory of Flankers and continues to build various Chinese variants. It'll be valuable for China since China reverse-engineered several variants but unlikely have access to the original design data. The TVC of 117S would also be of interest potentially. But, at the end of the day, Su-35 is a very good 4++ generation fighter aircraft, so having a squadron of it joining China's large Flanker fleet certainly is helpful and is not a terribly new experience.

Importing Su-35 from Russia doesn't have much to do with J-20 and its development. The author, like some other pundits, was really just grasping for evidence to support their preconceived conclusion. The official introduction of J-20 is psychologically unsettling for some. Its' a game-changer. No other country outside the US has a fifth generation stealth fighter yet. Never in the history has PLAAF owned any world-class fighter aircraft that is in the same generation as the best in the world (well, maybe Mig-15 was, but that was designed and manufactured by USSR). Its impact is as much in psychology as in air combat, since in this day and age the probability of having a war between big powers involving stealth fighters is not very high. That's why you see all these pundits going out of their way to disapprove that J-20 is a worthy world-class stealth fighter. The source of one sense of superiority and exclusivity would be deprived.

 

[Blitzo]

Interesting take on the J-20.

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Can we not post anything from Dave Majumdar?

And the same goes for Kyle Mizokami and David Axe. They're all birds of a feather...


The National Interest sometimes has good contributions, but that is really dependent on their guest contributors. Unfortunately many of their regulars are utterly terrible.

In particular I despise their sensationalized clickbait titles and "vs" articles like "fighter a vs fighter b! Won wins?" It is the equivalent of tabloidism for geopolitics and defence news.

I hope you are posting this with an air of irony.

 

[vincent]

Interesting take on the J-20.

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The entire argument is based on the assumption China did buy Su-35, which we have yet to see in PLAAF colours

 

[Blackstone]

Can we not post anything from Dave Majumdar?

And the same goes for Kyle Mizokami and David Axe. They're all birds of a feather...


The National Interest sometimes has good contributions, but that is really dependent on their guest contributors. Unfortunately many of their regulars are utterly terrible.

In particular I despise their sensationalized clickbait titles and "vs" articles like "fighter a vs fighter b! Won wins?" It is the equivalent of tabloidism for geopolitics and defence news.

I hope you are posting this with an air of irony.

Seriously, Blitzo? I took you to be the 'marketplace of free ideas, and let the best one win' kind of person.

I'm generally weary of media from The National Interest, because it's the neocon waterhole, with its own narrow-view agendas. Nevertheless, it's good to read such sources, even if for no reason other than "keep the Bible in one hand, and the New York Times in the other, so you know what both camps are thinking."