Chengdu J-20 news and analysis Part III
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The key quote from VH that began this discussion can be traced back from Schneider's lackluster USNI piece (he's more of a nuke wonk) to a non-attributed quote in faux newspaper Business Insider, which is actually an aggregator augmented by low-experience bloggers. The author of that particular piece is a 2015 college grad fresh from an internship gig at Atlanta's Creative Loafing, so we can pretty much guarantee that the context is wrong.
Afterburning flat nozzles are good for stealth (unless you have the burners on, in which case it don't matter a lick) but the problem is all that hot, high-pressure air that wants nothing more than to make them round, as the laws of physics dictate.
Afterburning flat nozzles are good for stealth (unless you have the burners on, in which case it don't matter a lick) but the problem is all that hot, high-pressure air that wants nothing more than to make them round, as the laws of physics dictate.
Airplane said:
You should reconsider your statement that Chinese engineering is 'extremely good' According to these recent public experiences with Chinese engineering the verdict has come down that Chinese engineering is shoddy and in many cases dangerous to the end user. And do not forget that even after many years and investments of billions of dollars the Chinese still cannot build a decent jet engine.
Check out this story on electric buses being manufactured by Chinese company BYD, and in service with LA Metro:
"But largely unbeknownst to the public, BYD's electric buses are contending with a record of poor performance and mechanical problems."
http://www.latimes.com/local/lanow/la-me-electric-buses-20180520-story.html
And of course there is this report on the Chinese manufactured Bay Bridge in San Francisco which is falling apart due to shoddy workmanship and poor welds after just 12 years in service.
http://media.sacbee.com/static/sinclair/sinclair.jquery/baybridge/index.html
Deino said:
You should recall that Russian AWACS monitored allied air operations during the Gulf war from orbits over the Caspian Sea. If that happened it is highly possible that Indian AWACS cued by intelligence were able to track and detect the J-20 during its deployment to Tibet. The Indians are not chumps when it comes to air operations. Their prowess was discovered during their participation at Red Flag.
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VH said:
As in all things, "it depends". I certainly wouldn't consider this a product of "shoddy engineering":
https://www.youtube.com/watch?v=SoLNgmrxwIM
Then you have smartphones, computers (China leads the world in supercomputing now), as well as basic manufacturing. I recently bought a Kevin John Venom (knife - don't know where they come up with the names) straight from China for $230 shipped. Better build quality than most of the rest of my knives at a fraction of the price. Even mom & pop shops in China are modernizing.
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Sounds like Pierre Sprey has been visiting India and has a few new followers there (Stealth is a Myth), India PR.
The possibility mentioned that the J-20 had its lens reflector deployed makes sense. Wouldn't Indian operators know the difference?
Could atmospheric conditions make stealth aircraft more visible (wet, rain), wonder what the conditions were if indeed India was able to track with the MKIs or AWACs. Just putting it out there.
The possibility mentioned that the J-20 had its lens reflector deployed makes sense. Wouldn't Indian operators know the difference?
Could atmospheric conditions make stealth aircraft more visible (wet, rain), wonder what the conditions were if indeed India was able to track with the MKIs or AWACs. Just putting it out there.
icyplanetnhc (Steve)
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It certainly does seem like the J-20 design made some compromises in terms of low observability and it likely won't reach the level of signature reduction of the F-22, but perhaps that wasn't the goal in the first place. That said, in the Pacific, operational considerations would make range a greater design driver. I wouldn't dismiss Chinese engineering and manufacturing out of hand; for instance, consumer electronics are generally of good quality. You can also point out engineering failures of any country so singling out any one in particular isn't very constructive, and to be frank a certain poster here comes across as having some kind of vendetta.
However, even though it is advancing at a remarkable rate (some of it no doubt through IP theft), China still lags the West in terms of experience and technology in several key fields in aeronautics, with propulsion being the most obvious.
However, even though it is advancing at a remarkable rate (some of it no doubt through IP theft), China still lags the West in terms of experience and technology in several key fields in aeronautics, with propulsion being the most obvious.
sferrin said:
What I *tried* to say is: it's not the Chinese industry that would quit and wait for better, but PLAAF. If J-20 was so unsatisfactory for PLAAF, then they would likely not buy it. They would just pay for some research programmes for low observable tech like BAE's Replica, maybe even some flying demonstrator, like SAC did with FC-31, but would not pay for research of myriad of other subsystems and their integration into an actual combat flying machine. It'd still be expense for Chinese MoD, of course, but most of the money would be "saved" and could be channeled into other viable PLAAF needs.
kcran567 said:
Indeed, would they?
Not impossible, but considering when the requirements for J-XX would've been put out the PLAAF would've likely wanted the aircraft to operate in the westpac environment (including ECS and SCS and beyond) which can be pretty wet and rainy, I would be surprised if they hadn't kept such demands in mind. Not to mention the aircraft would've considered operations for an India contingency in mind as well...
Steven said:
All aircraft are indeed a result of compromise between various different performance demands operating under the level of echnology that a nation's industries have mastered.
Range vs kinematic performance vs RF VLO vs IR VLO vs internal payload vs cost vs maintainability etc for each and every aircraft are tweaked a bit to match a nation's own optimal demands and operational preferences.
Of course, the quote from the "Lockheed scientist" is vague enough that it could mean anything. "not fully understanding" all the "concepts" of LO design in this case could literally be the guy saying, oh look J-20's engines have round nozzles without serrations that is obviously not quite as stealthy as an F-22's F119 engine nozzles -- or on the other end of the spectrum it can be what a few people seem to be insinuating,like the developers of J-20 and/or the PLAAF have basically chosen to ctrl+c, ctrl+v a few random bits and pieces of external superficial stealth shaping from US stealth fighters without actually doing any research, development or trials to see how it all works together on the aircraft.
icyplanetnhc (Steve)
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Blitzo said:
Well, Chengdu does appear to take many cues from Western VLO designs through both publicly available information and (almost certainly) espionage. Even VLO shaping itself consists of tradeoffs and compromises. While the stealth of the J-20 is no doubt more complex and nuanced than what most of us can eyeball, it's likely that engineer from a company with extensive VLO experience like Lockheed would be able to identify design features that he wouldn't agree with, at least from a VLO perspective.
But again, the J-20 doesn't need to compete with the F-22 in every characteristics to be able to perform its intended mission.
Steven said:
Considering most international stealth fighter projects that are emerging take quite a fewcues from designs first pioneered by US stealth fighters, yeah.
Tbh this is something that I've never contested since we first saw the photos of J-20 back in late 2010. It would have been concerning if J-20 did not feature similar stealth shaping principles to other stealth fighters.
Assuming that the article is not talking out of its backside and they actually managed to get a LockMart scientist or engineer to make a serious and informed comment about the J-20 based off various photos -- the statement itself is still so damn vague that one could ascribe whatever meaning to it that we wanted.
Even we are able to easily ID a few points of J-20's design and configuration which are obviously not as stealthy as it could be. The current Al-31 engines for example have round nozzles without serrations. The actuators under the wing are F-22 style rather than flat like the F-35. So is that what the guy means?
Or, is it more extreme like what some people here suggested, like CAC literally copy and pasted bits and pieces from F-22 and F-35 without actually thinking about what they were doing and applying their own R&D?
Agree, but also not really what this discussion over the last few pages seems to have been about. Rather, the discussion is more about interpreting what on earth the Lockmart guy meant.
Nobody mentioned that maybe the Indians' did detect the J-20... But did the J-20 have the final definitive (F-35 type-chevron-axisymmetric) nozzle on during the supposed detection. That would make a big difference, no?
Flat nozzles were mentioned in an earlier post, doesn't the F-35s nozzle match or surpass the F-22s?
Did the Indians claim Radio/Radar detection, IR detection, or both?
Flat nozzles were mentioned in an earlier post, doesn't the F-35s nozzle match or surpass the F-22s?
Did the Indians claim Radio/Radar detection, IR detection, or both?
kcran567 said:
In service J-20s certainly are not flying with serrated F-35 nozzles -- but would it make that big of a difference in this case?
For example, if F-35's F-135 serrated nozzle was replaced with a nozzle more akin to, say what the F110 on an F-16 has, how much bigger of an RCS would it have to allow the IAF commander to make such ambitious claims?
My suspicion, assuming the IAF commander isn't just making stuff up for political reasons, is the J-20s likely had luneberg lenses, and either the IAF recognizes they had luneberg lenses and are choosing to report it anyway for PR where such talk is of little consequence, or that the IAF did not realize the J-20s had luneberg lenses on which would be a much bigger concern.
Pretty sure they were claiming Su-30 radar and "ordinary radar stations"
are able to detect J-20. So RF.Since the J-20 has been deployed over ocean areas it will soon be able to assess the true radar signature of the Chinese fighter and see how easy it is to detect and track.
"..The People’s Liberation Army Air Force’s (PLAAF) purported first fifth-generation stealth fighter aircraft, the Chengdu Aerospace Corporation (CAC) J-20A multirole fighter, conducted its first over-the-sea combat exercise, the PLAAF announced this week."
https://thediplomat.com/2018/05/chinas-j-20-fighter-undergoes-first-over-the-sea-combat-training/
"..The People’s Liberation Army Air Force’s (PLAAF) purported first fifth-generation stealth fighter aircraft, the Chengdu Aerospace Corporation (CAC) J-20A multirole fighter, conducted its first over-the-sea combat exercise, the PLAAF announced this week."
https://thediplomat.com/2018/05/chinas-j-20-fighter-undergoes-first-over-the-sea-combat-training/
latenlazy
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This “maybe China doesn’t know how to do VLO designs because it allegedly doesn’t jibe well with the eyeballs of a nameless LockMart guy quoted in a clickbait article” is a silly point of contention. Regardless of what details anyone thinks they can ascertain from their eyeballing, at the end of the day a plane’s RCS is measurable and we can be sure that CAC the PLA will have measured it with the J-20. Regardless of what details one can nitpick at in a photo what ultimately matters is how a design does with those tests. If the J-20’s RCS wasn’t up to spec then it would still be in development. There’s nothing magical or secret about the science of stealth, nor is there only one way to do stealth. I find it more than a little telling that some of the same guys who are lobbing accusations that China must have stolen and copied technology for the J-20 are also insisting that the J-20 must be deficient because it doesn’t match the same surface details or design choices of the designs it’s allegedly copied. One would think that if Chinese engineering and design chops weren’t up to par they would have just stuck with the same techniques of the evidently “superior” solution given the data they acquired, especially since the value of that data is mostly in the *details*. If someone is trying to have it both ways maybe they’re not being completely genuine about their arguments going either direction.
latenlazy said:
Nah, what some people seem to be saying is to try and get the best of both worlds:
A: J-20 only "looks" superficially similar to F-22 and F-35, and directly copies and pastes bits from those aircraft... but...
B: ... they "only" directly copy/pasted bits of those aircraft without actually understanding what they were doing and implying their testing and trials of what they copied were also somehow incompetent/not reflective of good understanding of RF stealth.
Putting it another way, they're saying J-20 is a copy of various bits of aircraft all mixed together in a way that doesn't work and only looks stealthy but really isn't. :
Really? It would be interesting to hear the other ways you can achieve stealth without resorting to tried and proven methods. For example the J-20 has chosen to go their own way by using anhedral in their design of canards where the Russian Su57 also uses canards but uses movable Leading Edge Root eXtensions(LERX), which are considered much more stealthy. Many consider the Su-57 more stealthy because of the way the canards are integrated into the plane of the LERX. Perhaps the design of the J-20 canards was a compromise the Chinese chose to live with. Like the round engines nozzles of the J-20.latenlazy said:
latenlazy
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Does the B2 achieve VLO the same way as the F-117? Does the F-22 achieve VLO the same way as the B-2? So yes, really. There are multiple different techniques used to achieve VLO. Sometimes they’re used in conjunction and in different combinations for different designs.VH said:
You can’t cherry pick individual features to make judgments about RCS. The whole airframe must be gauged as a cohesive system. The F-22 has large corner reflectors at its inlets from boundary layer diverters that the J-20 doesn’t have. Does that make it less stealthy than the J-20?
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Re. the Indians' claimed detection of the J-20 . . . could the circumstances be similar to this ?
http://uk.businessinsider.com/strange-notches-on-f-35-raise-questions-over-first-combat-with-israel-2018-5?r=US&IR=T
"F-35s deployed abroad usually feature their typical four radar reflectors: to exaggerate their real RCS (Radar Cross Section) and negate the enemy the ability to collect any detail about their LO “signature”. As happened during the short mission to Estonia and then Bulgaria, carried out by the USAF F-35As involved in the type’s first overseas training deployment to Europe or when, on Aug. 30, 2017, four U.S. Marine Corps F-35B Lightning II joined two USAF B-1B Lancers for the JSF’s first show of force against North Korea: the F-35Bs flew with the radar reflectors, a sign they didn’t want their actual radar signature to be exposed to any intelligence gathering sensor in the area."
cheers,
Robin.
http://uk.businessinsider.com/strange-notches-on-f-35-raise-questions-over-first-combat-with-israel-2018-5?r=US&IR=T
"F-35s deployed abroad usually feature their typical four radar reflectors: to exaggerate their real RCS (Radar Cross Section) and negate the enemy the ability to collect any detail about their LO “signature”. As happened during the short mission to Estonia and then Bulgaria, carried out by the USAF F-35As involved in the type’s first overseas training deployment to Europe or when, on Aug. 30, 2017, four U.S. Marine Corps F-35B Lightning II joined two USAF B-1B Lancers for the JSF’s first show of force against North Korea: the F-35Bs flew with the radar reflectors, a sign they didn’t want their actual radar signature to be exposed to any intelligence gathering sensor in the area."
cheers,
Robin.
robunos said:
Yeah, luneberg lenses have been mentioned a few times and most photos of J-20 flying shows it with a luneberg lens.
Of course the question that's been raised a few times is whether the IAF would be able to tell the J-20 had a luneberg lens aboard... one would certainly hope so.
There are more ways to detecting the J-20 than encountering an aircraft using a radar enhancing luneberg lens. The IR signature can provide valuable tracking data about the intruder aircraft. Especially since the J-20 with its inability to supercruise without the use of afterburner would light up the sky. If the J-20 deploys to the coastal regions it will have to manage how it conducts patrols to avoid long range detection by marauding Japanese F-35s. A mix of JSDF F-35s and F-15s could provide a credible counter to the J-20. This could get interesting.
"What the F-35 can already do is act as a sensor. Its Distributed Aperture System (DAS) can pick up the infrared emission of a threat, its computers can pinpoint the threat’s location, and its network connections can transmit tracking data to the rest of the force."
http://www.northropgrumman.com/Capabilities/ANAAQ37F35/Pages/default.aspx
"What the F-35 can already do is act as a sensor. Its Distributed Aperture System (DAS) can pick up the infrared emission of a threat, its computers can pinpoint the threat’s location, and its network connections can transmit tracking data to the rest of the force."
http://www.northropgrumman.com/Capabilities/ANAAQ37F35/Pages/default.aspx
VH said:
Err obviously there are multiple ways of detecting and tracking a stealth aircraft.
But the question from robunos was about the circumstances of the Indian claim for detecting the J-20, which was that the Indians claimed they detected it with radar. So in that case obviously the luneberg lens would be a relevant factor.
You are correct of course regarding the various ways of detecting the J-20. The new question on the table will be how the J-20 fares against JSDF and American F-35s in the Pacific theater especially when F-35 is part of a networked air defense system and when J-20 must resort to using its afterburner to supercruise.
Airplane
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sferrin said:
Just about everyone in every discussion comparing the gummed down performance from the -22 to the -35.
'The F-35 does not need to maneuver as well as an F-22'
'The F-35 does not need to supercruise like an F-22'
But again, the poster I replied to said the J-20 doesn't supercruise without AB when comparing it (J-20) to an F-35. The F-35 doesn't supercruise at all... So what's the advantage? The J-20 *will* supercruise with new engines... The F-35 will never supercruise even if you plucked an engine out of Clint Eastwood's Firefox and bolted it up to a -35.
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Airplane said:
The F-35 doesn't need to. It's not an F-22. It was never designed to be an F-22. It's like complaining the F-16 can't carry as many missiles as the F-15, isn't as fast, and doesn't have as capable of radar. Does that mean the F-16 sucks in air combat? Obviously not.
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Not quite, the question I was asking was, do any of the experts her think that the J-20, that was claimed to be detected by the Indian Su-30, was fitted with a radar reflector (luneberg lens) in order to mask it's LO characteristics, rather than just increase it's RCS for safety reasons ?
cheers,
Robin.
sferrin said:
The issue is that some decision makers justified the 187 aircraft F-22 production cap in light of the F-35's capabilities. They believed that resources should be shifted to the multirole F-35 to allow proliferation of a fifth-generation fighter to all three service branches. The United States Air Force still has to make up for a shortfall of 194 F-22 aircraft. Does the United States Air Force address this shortfall with the F-35, an improved F-15, and/or an arsenal plane?
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Triton said:
I think by "some" you mean TWO: Robert Gates and the devil on his shoulder whispering in his ear; Gordon England. The USAF certainly didn't feel that way. In fact, at one point the USAF was willing to cut their F-35 order by 500 (five-zero-zero) F-35s if they could have got another 100 F-22s.
sferrin said:
Don't forget Secretary of Defense Donald Rumsfeld, Senator John McCain, Chairman of the Senate Armed Services Committee John Warner, and General James Cartwright, Vice Chairman of the Joint Chiefs of Staff.
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Re: Mitsubishi/LM F-22J Super Raptor/ F-22/F-35 hybrid ?
That is one of the main reasons to fit a radar reflector. Accurate measurement of the RCS is to be avoided where possible.
robunos said:
That is one of the main reasons to fit a radar reflector. Accurate measurement of the RCS is to be avoided where possible.
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The discussion about a Japanese "Super Raptor" or a LM F-22/F-35 hybrid were split from
this topic and the discussion can now be proceeded with here (without damaging this thread):
https://www.secretprojects.co.uk/forum/index.php/topic,30367.msg330240/boardseen.html#new
this topic and the discussion can now be proceeded with here (without damaging this thread):
https://www.secretprojects.co.uk/forum/index.php/topic,30367.msg330240/boardseen.html#new
FighterJock
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Jemiba said:
Thanks Jemiba.
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