Chengdu J-20 5th Generation Aircraft News & Discussions

[SQ8]

I am more clear about this than you are.


When there is an urgent need to advance, you do not reinvent the wheel, as the Chinese members here often said and they have no problems with industrial espionage and emulation of current technology and methods.

For example...

Who is the world's premier naval aviation power? China? Or is it US? So when you look at the new Chinese aircraft carrier, look at how similar their crew are to ours in terms of deck ops and appearance. Why? Because we did all the guesswork, explored the risks, shed blood, lost lives, refined what works, and continue the process all over again. So why should the PLAN look at anyone else? The PLAN may alter some deck ops a bit because of the differences between its carrier and the American versions, but the core of each deck operation remains the same because we proved it worked over the decades.

Ever marshal an aircraft?

Aircraft marshalling - Wikipedia, the free encyclopedia

Where was the PLAAF when this method of silent but visual communication between pilot and ground crew was developed? More like the PLAAF did not exist. That is not a criticism but a statement of fact. So when the PLAAF came to be, why should it changed what worked across the decades and countries?

Bottom line is this...China IS copying and/or stealing technology, adapting methods and accepting foreign ideas in order to advance.


Simply is too harsh. But there is no denying that in the process of copying from others, one's own products will inevitably suffer Quality Assurance issues.

I work for a major NAND FLASH manufacturer. We buy often from the 'gray market' and disassembled what we bought to investigate who is masquerading as us, as in selling crap under our company name, in order to assure new customers and reassure nervous current ones, that when they buy from us, they are buying the real products. Not crap repackaged by unscrupulous so-called 'manufacturers' from mainland China.

My competitors in South Korea, Japan, and Europe does the same.

I do not have the chance to examine a purely Chinese manufactured aircraft but am wiling to bet renmibi to rice cakes that based on my 10yrs in the USAF I will find plenty that are subpar to our MIL standards. Done it to the Soviet MIGs.


If you are talking about this contraption for the J-20, then explain what problem(s) is it trying to solve?


No need to address the rest of your post.

Having worked with "actual" TI(Texas Instruments Chips) and counterfeit TI (ironically both made in China), I can vouch for those QA issues.
However, those do get sorted out eventually simply due to the fact that they go through thousands to get it right.
QA still plagues many Chinese products because the skilled worker base is still to develop. After all, you need qualified and experience technicians and engineers to produce something like a substrate. You cant take workers off a screwdriver line and expect them to make ICs just as well. This trend is changing though.
I worked on Harris,ASELSAN and Chinese hardware at the same time.. and both the Harris and ASELSAN systems were equally comparable in quality(sophistication was up to us, we designed the crypto modules and others). The Chinese system on the other hand, suffered from quality and reliability issues during the initial period. Only after multiple visits by our teams to China and countless returns did the quality improve..and it did considerably so that the later batches were equally well built and reliable as the Harris and ASELSAN products. It's just a cultural thing, and it will take time to cause a cultural change within that manufacturing mindset.

In Pakistan's case, due to the fact that we've worked with the F-16's and their quality for over 35 years..along with french hardware.. that QA went into the JF-17. A lot of the test systems during manufacture for the aircraft are US made. So that quality gets worked in. The example that went down.. ended up being attributed to the Russian RD-93 engine.


For the last part of your post, I suggest that you do not reply to such posters and concentrate on your technical material and knowledge to post. That ensures a posts validity no matter what slander is taken. Chinese, Viets or otherwise arent the only audience for posts and you do not have to justify everything. Posts Justify themselves.

 

[Sanchez]

Having worked with "actual" TI(Texas Instruments Chips) and counterfeit TI (ironically both made in China), I can vouch for those QA issues.
However, those do get sorted out eventually simply due to the fact that they go through thousands to get it right.
QA still plagues many Chinese products because the skilled worker base is still to develop. After all, you need qualified and experience technicians and engineers to produce something like a substrate. You cant take workers off a screwdriver line and expect them to make ICs just as well. This trend is changing though.
I worked on Harris,ASELSAN and Chinese hardware at the same time.. and both the Harris and ASELSAN systems were equally comparable in quality(sophistication was up to us, we designed the crypto modules and others). The Chinese system on the other hand, suffered from quality and reliability issues during the initial period. Only after multiple visits by our teams to China and countless returns did the quality improve..and it did considerably so that the later batches were equally well built and reliable as the Harris and ASELSAN products. It's just a cultural thing, and it will take time to cause a cultural change within that manufacturing mindset.

In Pakistan's case, due to the fact that we've worked with the F-16's and their quality for over 35 years..along with french hardware.. that QA went into the JF-17. A lot of the test systems during manufacture for the aircraft are US made. So that quality gets worked in. The example that went down.. ended up being attributed to the Russian RD-93 engine.


For the last part of your post, I suggest that you do not reply to such posters and concentrate on your technical material and knowledge to post. That ensures a posts validity no matter what slander is taken. Chinese, Viets or otherwise arent the only audience for posts and you do not have to justify everything. Posts Justify themselves.

Oscar, it's a shame on you to be a Senior modurator. You have no say about what China have provided to Pakistan. You have no idea about real QA means in aerospace industry, do you?

You are not in a position to critisize Chinese quality of military aids that pakistan has received or bought from China, do you?

I see how you wish to please this Vietnamesae American, shame on you!

 

[SQ8]

Oscar, it's a shame on you to be a Senior modurator. You have no say about what China have provided to Pakistan. You have no idea about real QA means in aerospace industry, do you?

You are not in a position to critisize Chinese quality of military aids that pakistan has received or bought from China, do you?

I see how you wish to please this Vietnamesae American, shame on you!

Shame on you.
How do you know I have no say? Have you worked in the industry as I have?
Do you know people in the industry as I do?
NO.
Shame on you twice more, because in your pointless defence you ignored the underlying causes I have for the problems.
Shame on you thrice, as you ignored how I stated these improvements were made and are made.

Shame on you as a Chinese for eternity, because you have no idea what China has given and not given. You have no idea how Chinese realize these issues and strive to improve them. You are insulting their efforts by pretending its all ok.
Shame on you for resorting to a cheap attack for a cheap defense when it is not needed.

 

[v9s]

Oscar, it's a shame on you to be a Senior modurator. You have no say about what China have provided to Pakistan. You have no idea about real QA means in aerospace industry, do you?

You are not in a position to critisize Chinese quality of military aids that pakistan has received or bought from China, do you?

I see how you wish to please this Vietnamesae American, shame on you!

LOL.... buddy, have you ever ventured outside the Chinese Defence section of PDF?

Oscar knows what he's talking about.

 

[j20blackdragon]

I work for a major NAND FLASH manufacturer.

So the bottom line is that you work in the semiconductor industry, which has nothing to do with aerospace and stealth.

 

[Beast]

Shame on you.
How do you know I have no say? Have you worked in the industry as I have?
Do you know people in the industry as I do?
NO.
Shame on you twice more, because in your pointless defence you ignored the underlying causes I have for the problems.
Shame on you thrice, as you ignored how I stated these improvements were made and are made.

Shame on you as a Chinese for eternity, because you have no idea what China has given and not given. You have no idea how Chinese realize these issues and strive to improve them. You are insulting their efforts by pretending its all ok.
Shame on you for resorting to a cheap attack for a cheap defense when it is not needed.

You have no idea this gambit come in here with the intention of smearing anything regarding Chinese. Accept criticism is one thing but outright distorting of facts and coming with an agenda is another thing. Check out gambit pass record, he has not even say a single word of positive regarding china. Everybody can see with their eyes.

 

[gambit]

So the bottom line is that you work in the semiconductor industry, which has nothing to do with aerospace and stealth.

Prior to the current career, there was nearly 19 yrs in aviation, which includes 10 yrs active duty USAF on the F-111 and F-16, then nearly 9 yrs in various radar related work, from system integration to designing field tests, mostly altitude over the waters off Florida. Company shall remain unnamed but since then has been absorbed by a larger defense contractor.

 

[gpit]

Mine came as well...From laughing...From looking at this missile rail contraption...

The foundation of radar detection is reflection and in radar detection, if the goal is about 'stealth', the multiple reflections are bad. Very very bad.

When a radar signal hit something like the above, there will be interference from multiple reflections: Constructive and Destructive.

Regarding 'stealth':

Destructive Interference = Good
Constructive Interference = Bad

Keyword search for you: Wave superposition. Destructive interference cancels colliding signals. Constructive interference amplifies and make coherent stronger signals.

So if we take a look at this...

Any approach angle will inevitably produces multiple reflections between the missile and the fuselage. How is this any better than an opened weapons bay? It is not.

The Chinese 5th Generation Fighter Has Some Truly Clever Engineering
David Cenciotti, The Aviationist

In order to preserve their stealthiness and keep the RCS (Radar Cross Section) as low as possible, radar-evading planes rely on weapons bay: bombs and missiles to be fired are kept inside the bays until it’s time to use them.

For instance, the F-35 can carry one AIM-120D (AIM-120C8), on a trapeze : when needed, the BVR (Beyond Visual Range) missile is lowered into the airstream on the open bomb bay door, and ejected.

F-22 Raptors use canted trapeze to put the AIM-9 Sidewinder seeked into the airstream to achieve a lock on the target as the side bay doors are open.

Once the missile is fired, the bay doors close up.

Obviously, such method requires the stealth plane to fly with the open bay doors for a certain amount of time, a condition that can limit the aircraft performance, maneuverability, and increases the overall plane’s RCS, with a temporary exposure of the aircraft to the enemy radars.

Something that can be quite lethal in a Within Visual Range scenario.

The problem is to be partly solved with the use of missiles featuring the Lock On After Launch capability. With this kind of missile (available on the Raptor when the AIM-9M will be replaced by the AIM-9X Block II) the bay doors remain open just the time it is needed to eject the missile into the airstream.

However, China might have found a clever solution to the problem, as the latest images of the J-20 Mighty Dragon stealth fighter jet, emerging from the Chinese Internet, seem to suggest.

Indeed, the second prototype of the aircraft features a missile deployment device on the side weapons bay which extracts the selected air-to-air missile and then closes the door to keep the reduced RCS.

Simpler and probably cheaper than the use of LOAL missiles, the J-20′s deployment device shows that Chinese engineers are not simply copying U.S. tech: if not improving it, they are at least troubleshooting some of the issues already faced by their American counterparts, with some clever ideas.

The missile launch rail was used to carry the PL-10 IR air-to-air missile during tests

http://www.businessinsider.com/chinese-j20-fighter-has-clever-upgrades-2013-3

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[Martian2]

Chengdu J-20 revolving weapon bay is superior in stealth to F-22 traditional weapon bay

At Gambit:

I came back for a few minutes to find my citation on the China-Sudan Friendship Bridge and I find you are still making clearly erroneous claims regarding the Chengdu J-20 stealth fighter. Your claim is clearly wrong, because the physics is straightforward.

An air-to-air missile has a very small RCS (radar cross section) compared to an opened weapon bay door. The Chengdu J-20's ingenious revolving bay door minimizes the time that the J-20 bay door stays open. Hence, the J-20 stays stealthier in launching an air-to-air missile.

Anyone that understands high school physics can clearly see the side profile of an air-to-air missile is much smaller than an opened weapon bay door.

The small red box represents the maximum side RCS for an air-to-air missile. The large red box represents the maximum side RCS of an opened weapon bay door. Obviously, the large red box is much bigger than the small red box. Hence, the Chengdu J-20 rotary weapon bay door reduces the exposure time of the large red box and confines the RCS reflection to the size of the small red box. In simple terms, the innovative Chengdu J-20 rotary weapon bay is superior to the traditional F-22 weapon bay for stealth.

One more thing, in post #3152, you/Gambit claimed interference negated the advantage of having a closed weapon bay door. Your analogy does not apply. You have forgotten that the Chengdu J-20 is a stealth fighter with RAM (radar absorbent material) coating on the outer panel of the weapon bay door. The RAM should absorb about 99.684% of the radar energy on the first bounce. There will be virtually no interference.

[Note: I don't have the time to keep refuting Gambit's crazy claims that contradict physics. I just happened to be in the neighborhood hunting down the China-Sudan Friendship Bridge citation.]

 

[Sasquatch]

Please get back onto the topic now and not get sidetracked.

 

[gambit]

I came back for a few minutes to find my citation on the China-Sudan Friendship Bridge and I find you are still making clearly erroneous claims regarding the Chengdu J-20 stealth fighter. Your claim is clearly wrong, because the physics is straightforward.

An air-to-air missile has a very small RCS (radar cross section) compared to an opened weapon bay door. The Chengdu J-20's ingenious revolving bay door minimizes the time that the J-20 bay door stays open. Hence, the J-20 stays stealthier in launching an air-to-air missile.

Anyone that understands high school physics can clearly see the side profile of an air-to-air missile is much smaller than an opened weapon bay door.

The small red box represents the maximum side RCS for an air-to-air missile. The large red box represents the maximum side RCS of an opened weapon bay door. Obviously, the large red box is much bigger than the small red box. Hence, the Chengdu J-20 rotary weapon bay door reduces the exposure time of the large red box and confines the RCS reflection to the size of the small red box. In simple terms, the innovative Chengdu J-20 rotary weapon bay is superior to the traditional F-22 weapon bay for stealth.

One more thing, in post #3152, you/Gambit claimed interference negated the advantage of having a closed weapon bay door. Your analogy does not apply. You have forgotten that the Chengdu J-20 is a stealth fighter with RAM (radar absorbent material) coating on the outer panel of the weapon bay door. The RAM should absorb about 99.684% of the radar energy on the first bounce. There will be virtually no interference.

And you have the gall to lecture me about physics?

Is the missile transparent to impinging radar signals? We can safely assume -- NOT. Sorry, but we are dealing with real physics here. Not 'Chinese physics'.

The missile will present a smaller RCS profile than an opened weapons bay, but its presence WILL rise the J-20 above the clutter rejection threshold, that is assuming we are generous enough to say that the J-20 is 'stealthy' enough to be below that threshold in the first place.

[Note: I don't have the time to keep refuting Gambit's crazy claims that contradict physics. I just happened to be in the neighborhood hunting down the China-Sudan Friendship Bridge citation.]

And what laws of physics have I contradicted? The fact that you ignored that the missile itself have its own RCS and that missiles on wing tips are visible to radars mean it is still YOU who are ignorant and contradict real physics...

THz Radar Cross Sections »

The outline shapeof the airplane can be easily recognized. Also particular scatterers such as fuselage, tail,wings, end of the wings and even missiles are distinguishable.

Absorbers or not, an exposed missile will give the J-20 away as assuredly as an opened weapons bay will give the -22 away. Think about it, no matter how much the pain it will give you, if exposed missiles do not matter, then why enclosed them in the first place?

You think that your PLAAF is going to gain any tactical advantages with this contraption? In your dreams.

Here is how the USAF trains...In escalation of difficulty and lethality...

1- Basic Fighter Maneuvers (BFM) -- Except that this is not about flight school. It is about trained or even combat experienced pilots taking everything they know about air combat and pushed them and their knowledge to the next level.

BFM-Offensive: Put the pilot at a tactical advantage, which is behind an adversary, and trains him on how to maintain that advantage.

BFM-Defensive: Put the pilot at a tactical disadvantage, which is in front of an adversary, and trains him on how to extricate himself from that disadvantage and get into the Offensive.

BFM-Neutral: Pilot and adversary pass each other nose-to-nose at combined speed of over 1,000 kts and trains the pilot on how to achieve the Offensive.

BFM-Dissimilar: Put the pilot in Neutral and against an unknown adversary platform and trains him how to achieve the Offensive.

2- Air Combat Maneuvering (ACM) -- Put the pilot and his wingman against a single adversary and rotate all contestants through Offensive, Defensive, Neutral, and Dissimilar. This not only reinforced BFM lessons but also to train the pilot on how to coordinate his flying with his wingman to increase the odds of victory.

3- Air Combat Tactics (ACT) -- Put the pilot and his wingman against a pair of adversary. Again, rotate all contestants through Offensive, Defensive, Neutral, and Dissimilar.

ACT-Within Visual Range and ACT-Beyond Visual Range are self explanatory.

The most realistic is ACT-Dissimilar and our pilots went toe-to-toe against Russian line fighters. And no one can cheat with ACMI pods attached to his aircraft.

Your PLAAF have not even 1/10th the training syllabus of the USAF, let alone of the USN's Top Gun. If the J-20 is deployed with this contraption, we may take the -16, tape up its HUD, and disable one AoA probe, just to give the J-20 pilot a chance.

Heck, we may even make it even for the J-20 by going to the retirement homes in Florida, round up a few Vietnam War era geezer pilots, help them out of their walkers/wheelchairs, and put them into their old Phantoms and let them have a go at the J-20. The PLAAF might learn something there.

 

[gambit]

The Chinese 5th Generation Fighter Has Some Truly Clever Engineering
David Cenciotti, The Aviationist

In order to preserve their stealthiness and keep the RCS (Radar Cross Section) as low as possible, radar-evading planes rely on weapons bay: bombs and missiles to be fired are kept inside the bays until it’s time to use them.

For instance, the F-35 can carry one AIM-120D (AIM-120C8), on a trapeze : when needed, the BVR (Beyond Visual Range) missile is lowered into the airstream on the open bomb bay door, and ejected.

F-22 Raptors use canted trapeze to put the AIM-9 Sidewinder seeked into the airstream to achieve a lock on the target as the side bay doors are open.

Once the missile is fired, the bay doors close up.

Obviously, such method requires the stealth plane to fly with the open bay doors for a certain amount of time, a condition that can limit the aircraft performance, maneuverability, and increases the overall plane’s RCS, with a temporary exposure of the aircraft to the enemy radars.

In simple terms, the innovative Chengdu J-20 rotary weapon bay is superior to the traditional F-22 weapon bay for stealth.

Let us look at what a few Brazilians did...

Basically, the Brazilians did C-band simulations of a very EM significant area of a missile -- the rear section with its many corner reflectors thanks to the fin assembly. Then they compared it against actual EM anechoic chamber testing and found their simulation and real measurement correlate quite well.

But the experiment is not the point.

The point is that a missile have its own radar cross section (RCS), independent of whatever is attached to it, or whatever it is attached to, like an aircraft. And when physically associated with another structure, the missile's RCS will contribute to the total RCS that contains both aircraft and missile.

A missile is an EM mess when suspended under a wing.

Real physics and conventional logic would reason out that covering up the weapons bay while leaving the missile hanging in the EM wind is -- pointless.

But according to 'Chinese physics' and 'Chinese logic', once a missile is covered up by the weapons bay, EVERYTHING that the Brazilians theorized and correlated, ie surface currrents and corner reflections, would not exist or magically disappeared, even if exposed to EM radiation. For the Chinese hombres here, covering up the weapons bay is the end all. Never mind the original argument that the missile is the end all and covering it up until the last minute should be the objective.

Rube Goldberg have many complex mechanical methods to accomplish tasks. Would either one of you care to share with us your Rube Goldberg contraption to open a can? Me and my simple Wal-Mart bought hand turn can opener would be humbled.

At least when the J-20 is shot, the parachuting pilot can have peace of mind that it was not his weapons bay that gave him away.

 

[j20blackdragon]

The missile will present a smaller RCS profile than an opened weapons bay, but its presence WILL rise the J-20 above the clutter rejection threshold, that is assuming we are generous enough to say that the J-20 is 'stealthy' enough to be below that threshold in the first place.

Absorbers or not, an exposed missile will give the J-20 away as assuredly as an opened weapons bay will give the -22 away. Think about it, no matter how much the pain it will give you, if exposed missiles do not matter, then why enclosed them in the first place?

Since you've commented on exposed missiles and open weapon bays, what do you think about these gaps around the F-22's inlets?

How do we know the F-22 is 'stealthy' enough to be below your threshold in the first place?

 

[gambit]

Since you've commented on exposed missiles and open weapon bays, what do you think about these gaps around the F-22's inlets?

How do we know the F-22 is 'stealthy' enough to be below your threshold in the first place?

Send the J-20 with its new weapons bay protective contraption against the F-22 and find out...

 

[DrSomnath999]

1st of all I think at WVR warfare RCS / stealth is immaterial no matter how advanced one may built it's weapon bay/ missile launching platform as plane's IR signature is more important than plane RCS whther it is F 22 or J20


2nd thing F22 Exposed weapon bay time is very less in actual combat & it has far less 90 degree corner reflectors compare to the missile itself
as missile fins are aligned in 90 degree angulations making it excelllent surface for 90 degree corner reflections

so i dont think J 20 revolving missile launching platform holds any superior advantage in WVR warfare