The best critical analysis of j20 fighter

Damian

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So far most of your posts have been biased and illogical at time, not to mention you dont want to seem to gather all the facts before you start criticizing at some one.
Eh... not again...

China is not a raising power? Really? Unless you have been living inside a well the past 20years, its hard to miss, Have you seen the economic statistics?
Only because economy is rising it don't mean that some country will be a new superpower, there are other things that describes superpower like culture influance, R&D spending, technology level etc. etc. etc.

However they may catch up, just because someone started late does not mean they wont catch up because these technologies are slow to evolve there is ever possibility others may catch up.
They may catchup only if other will stop their R&D phase on further upgrading this and other types of technologies, and this will not happen.

Also its not a bad design haveing a big Delta Wing means there is more space for internal weapons load. The Delta wing is also the most Stealthy design by default. The Avro Vulcan was a good example of how Delta wings have low RC by default.
There are no 100% perfect design solutions.

J-20 is big so have more space for internal weapon bays, on the other way this makes it less Stealth than T-50 or F-22 because bigger size means more space reflecting radar waves.

Their is nothing like that, Both are good platforms, F-35 meant to be cheaper coz of one engine and same as F-16 back in 80s like f-35 now..
Yes, of course You are right, F-35 is good platform just different to F-22.

F-22 was designed as air superiority fighter superior to... well anything.

F-35 was designed as cheaper multirole fighter that was also intended for export so it is less Stealthy than F-22.
 

Godless-Kafir

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Canards will be made from composite radar absorbing material but that doesn't solve the problem it will increase the size on radar, Abt engines, Look at JSF engines you will notices a jig-jazz pattern at exhausts to minimize radar signature, F-22 use so does f-35, T-50-2 new engines probably have such things..

Regarding avionics, What language used to program, Its not mil standard i heard..
Dude Canards are just tail plane placed in the front, the only problem is that it creates more drag and its more unstable during supersonic flight.

Also composites are not visible to radars, the radar waves passes through them just like your micro wave oven does not heat plastics and only heats metals, thats why no one uses metal utensils inside a micro wave oven, because it is visible to the waves. I apologies for the kitchen analogy! :p
 

Kunal Biswas

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Dude Canards are just tail plane placed in the front, the only problem is that it creates more drag and its more unstable during supersonic flight.

Also composites are not visible to radars, the radar waves passes through them just like your micro wave oven does not heat plastics and only heats metals, thats why no one uses metal utensils inside a micro wave oven, because it is visible to the waves. I apologies for the kitchen analogy! :p

@GK,
F-117 and even F-22 are visible on radar that is present tech, First gen AESA dont even work a radar, they dont act like normal radars, Di-spite it made out of radar absorbing material nothing is 100% invisible, Stealth deign and powerful ECM pods are the key to 100% invisibility,

As for J-20 its canard increase reflection more than what PAK-FA and F-22 makes..
 

Kunal Biswas

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Yes, of course You are right, F-35 is good platform just different to F-22.

F-22 was designed as air superiority fighter superior to... well anything.

F-35 was designed as cheaper multirole fighter that was also intended for export so it is less Stealthy than F-22.
True but F-35 in US service are meant to replace older F-16 and in Navy F-18..

Also J-20 is bigger but probably agile, See a SU-30 have more AOA than smaller F-16, Also Present generation ECM can block Radars so does BVRs that means at some point CAC will occur..

As far as i know T-50 and F22 have TVC engines and J-20 dont..
 

Godless-Kafir

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Eh... not again...
I want my 4 hours back.! :rolleyes:
Only because economy is rising it don't mean that some country will be a new superpower, there are other things that describes superpower like culture influance, R&D spending, technology level etc. etc. etc.
In a way i agree that its not just economic power, if that was true Japan would be more powerful that what it should be but who is to say that China does not have R&D the J-20 its self is an example of its R&D catching up not to mention its numerous weapons system which are made in China now, they have a huge space programe and missile technology, they also make most of their weapons now, it does not matter if they are copies what matters is when the bomb falls.

They may catchup only if other will stop their R&D phase on further upgrading this and other types of technologies, and this will not happen.

There are no 100% perfect design solutions.
I agree that China will be behind in technology but what we should see is that Aviation is not like the Computer field where the technology doubles every 16 months, todays cell phone has more power than the 90s PC. The technology in the Aviation area is very slow to mature, the fastest aircraft(SR-71) was made in the 60s the most powerful rocket(Saturn-V) was made during the cold war, there is a glass sealing in this Aviation world which slows progress simply because of heavy costs for R&D and the natural limitations of physics on science, so that gives time for catching up. There are no leaps and jumps in this field like in many other fields. Thats why i mentioned Avionics being their Achilles heel.

J-20 is big so have more space for internal weapon bays, on the other way this makes it less Stealth than T-50 or F-22 because bigger size means more space reflecting radar waves.
Look at this way, even if you keep a large plastic tub inside the Micro Wave oven it does not heat up, compared to keeping a small metal pin which is easily heated up inside the oven, size is a big criteria only if they cant figure out how to use composites or RC reduction technology, also thats is why i used the example of Avro Vulcan, its not completely stealthy but at times it disappears from the radar owing to its shape.

Yes, of course You are right, F-35 is good platform just different to F-22.

F-22 was designed as air superiority fighter superior to... well anything.

F-35 was designed as cheaper multirole fighter that was also intended for export so it is less Stealthy than F-22.
F-35 is still not proven, so i wont know much to comment on that but it appears something can be done to reduce RC of an circular duct, may be material or angels.
 
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Godless-Kafir

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@GK,
F-117 and even F-22 are visible on radar that is present tech, First gen AESA dont even work a radar, they dont act like normal radars, Di-spite it made out of radar absorbing material nothing is 100% invisible, Stealth deign and powerful ECM pods are the key to 100% invisibility,

As for J-20 its canard increase reflection more than what PAK-FA and F-22 makes..
I hope you know, AESA or PESA all use Radar waves or Micro waves, the waves are not diffrent its only about how they use it. i understand saw tooth angles deflect radar at an acute angle, the J-20 as i told you is only a 4.5 gen aircraft because its not stealthy at all, i am NOT arguing against that but i think they will solve the issue.

Tell me how the Canard increases RC? The main wing has the same shape of an canard but its several times larger than a canard, so how do they reduce RC of the wing?
 

Damian

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In a way i agree that its not just economic power, if that was true Japan would be more powerful that what it should be but who is to say that China does not have R&D the J-20 its self is an example of its R&D catching up not to mention its numerous weapons system which are made in China now, they have a huge space programe and missile technology, they also make most of their weapons now, it does not matter if they are copies what matters is when the bomb falls.
R&D programs alone also don't mean anything, Ukraine have also R&D programs, or Germany have R&D programs, do they are superpowers?

Not to mention idiotic births policy in PRC and that they society will be getting older and older. Look at their agriculture? It is far from european standards even.

PRC will definetly be regional power but not global superpower.

I agree that China will be behind in technology but this is not like Computer field where the technology doubles every 16 months, todays cell phone has more power than the 90s PC. The technology in the Aviation area is very slow to mature, the fastest aircraft(SR-71) was made in the 60s the most powerful rocket(Saturn-V) was made during the cold war, there is a glass sealing in this Aviation world which slows progress simply because of heavy costs for R&D and the natural limitations of physics on science, so that gives time for catching up. There are no leaps and jumps in this field like in many other fields. Thats why i mentioned Avionics being their Achilles heel.
We will see, nano technology could be the key, and US is highly determined to field such technologies.

Look at this way, even if you keep a large plastic tub inside the Micro Wave oven it does not heat up, compared to keeping a small metal pin which is easily heated up inside the oven, size is a big criteria only if they cant figure out how to use composites or RC reduction technology, also thats is why i used the example of Avro Vulcan, its not completely stealthy but at times it disappears from the radar owing to its shape.
Forget about kitchen, more important than materials are size and airframe design, materials are less important.
 

Kunal Biswas

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Tell me how the Canard increases RC? The main wing has the same shape of an canard but its several times larger than a canard, so how do they reduce RC of the wing?
Simply its because its movable and if not reflect from one angle can be reflection to another angle by another source, Main wing indeed a big reflector but canards are additional, How to reduce RC of wings or aircraft is something we both know..
 

Godless-Kafir

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R&D programs alone also don't mean anything, Ukraine have also R&D programs, or Germany have R&D programs, do they are superpowers?
This is complete OT and i also disagree, germany was trying to become a super power during WW-2. Later on after WW-2 its the policy of Alliance that kept Japan and Germany down even though they where way ahead economically. Thats is why they where not able to use their economic clout to control others, China on the other hand has no such inhibition on it holding it back from useing its economic clout. It will not be as powerful as USA but it will definitely be the second most powerful nation, the muslims world may lean towards China if this so called Arab democracy ever clicks, the dictators where the ones who where keeping these people from being untied, now they will trouble Israel and they will elect which ever politican who will trouble Israel the most and to do that they may have to lean towards China for support. Such Axis may create problems and push China into the center stage.



Not to mention idiotic births policy in PRC and that they society will be getting older and older. Look at their agriculture? It is far from european standards even.
If they brought down the population, how do we know they wont use policies to reverse that later on?

China is the largest producer of Agriculture products by a long mile followed by India be it Rice, Wheat or grains it all comes from China. A lot of it is exported to Europe and US. You should have read into that.
PRC will definetly be regional power but not global superpower.
Its already a global power. No one can deny that because they also are building the muscle to back that!

We will see, nano technology could be the key, and US is highly determined to field such technologies.



Forget about kitchen, more important than materials are size and airframe design, materials are less important.
I was trying to explain in lay mans terms for you, all radars use Radio waves or micro waves. The oven is a great example to see how materials behave. Although size does increase RC the use of composites and shapes reduces it, not to mention the J-20 is not very big either, compared to F-22 or Pak-FA.
 

Godless-Kafir

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Simply its because its movable and if not reflect from one angle can be reflection to another angle by another source, Main wing indeed a big reflector but canards are additional, How to reduce RC of wings or aircraft is something we both know..
@KB but how do you think an composite structure can be visible to radar? Wont the Radar waves pass right through it even if the canard does move?
 

Kunal Biswas

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@KB but how do you think an composite structure can be visible to radar? Wont the Radar waves pass right through it even if the canard does move?
Composite material are solids hence reflect any wave through at them unless its a radar absorbing material which absorb radar waves by limiting within their honeycomb structure, second is anti radar paint which is popular on B2 bombers, Both technologies are now improved..

Btw, What type of composition you are mentioning where radar waves can pass through a solid structure ?
 

Godless-Kafir

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Composite material are solids hence reflect any wave through at them unless its a radar absorbing material which absorb radar waves by limiting within their honeycomb structure, second is anti radar paint which is popular on B2 bombers, Both technologies are now improved..

Btw, What type of composition you are mentioning where radar waves can pass through a solid structure ?
There are some composites or polymers which are not very visible to Radar but the problem of angling may be solved by makeing the canard function only when necessary like while take off or during high AoAs other times it may just sit there as a dummy air foil!

Not to mention the Pak-Fa has some sort of LEVCON which also moves, so wont that be reflective?
 

Kunal Biswas

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There are some composites or polymers which are not very visible to Radar but the problem of angling may be solved by makeing the canard function only when necessary like while take off or during high AoAs other times it may just sit there as a dummy air foil!

Not to mention the Pak-Fa has some sort of LEVCON which also moves, so wont that be reflective?
Ofcource that would be reflecting, But i am not buying sort of polymer coz its not possible, Any info detail abt the exact thing you are talking abt ?
 
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Drona

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Composite material are solids hence reflect any wave through at them unless its a radar absorbing material which absorb radar waves by limiting within their honeycomb structure, second is anti radar paint which is popular on B2 bombers, Both technologies are now improved..

Btw, What type of composition you are mentioning where radar waves can pass through a solid structure ?
Do you mean honeycomb structure like pyramidal RAM in Anechoic chamber ? for that hostile radar wavelength should be smaller than the distance between two pyramids or diameter of hexagon. If hostile radar is emitting radiation at 10 GHz , then its wavelength would be 3 cm , so having surface with roughness little over 3 cm like Anechoic chamber on surface of combat aircraft is impossible. RAM manufacturer can't really assume what kind radar hostile side going to use. Another radar absorption mechanism is to convert radar energy in to electrical or heat energy. to convert electromagnetic radiation energy in to electric energy, wavelength has to be equal to or smaller than visible light, and military radars uses far greater wavelength so this is not option. Another option is to convert radar energy in to heat energy, it possible up to certain extend, because, such RAM applied surface would already heated up due air-friction during flight. so RAM may not work effectively. (correct me,if I m worng).
 

p2prada

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In a way i agree that its not just economic power, if that was true Japan would be more powerful that what it should be but who is to say that China does not have R&D the J-20 its self is an example of its R&D catching up not to mention its numerous weapons system which are made in China now, they have a huge space programe and missile technology, they also make most of their weapons now, it does not matter if they are copies what matters is when the bomb falls.
The Israelis are way ahead of the Japanese, Indian and Chinese technology combined when it comes to Military technology. Heck Tokyo has a bigger GDP than Israel. But still Israel is ahead. Why? It is only because of the direction of resource spending. The Israelis have spent more per capita on military research than any of the other countries and they started it very early on with foreign assistance. Now the technological gap is such that we need to collaborate with these countries in order to reap the same benefits as we cannot do it alone. The Chinese have bigger problems than us, but they are making do by stealing the information.

The J-20 cannot be proven until the J-10 is inducted and proven. Simple as that. This is nothing different from our effort in making the Arjun. We don't even have basic technologies like engine and gun perfected let alone proving the entire tank in a battle.

Look at this way, even if you keep a large plastic tub inside the Micro Wave oven it does not heat up, compared to keeping a small metal pin which is easily heated up inside the oven, size is a big criteria only if they cant figure out how to use composites or RC reduction technology, also thats is why i used the example of Avro Vulcan, its not completely stealthy but at times it disappears from the radar owing to its shape.
The fact that plastics which are Microwave ready do not heat up is simply because the Microwaves does not use power that is high enough to heat it in the first place. The heat generated is not even close to the melting point of the plastic. There is no such thing as being invisible to EMR. Everything is visible to EMR. Nothing can escape it except for the famed God Particle and no one has been able to harness it let alone prove it exists. You don't know sh!t about EMR waves and it's general behaviour.

The Avro Vulcan can drop out of radar coverage owing to tactics and this is something all aircraft can do. Vulcan is nothing special. Delta is nothing special either. It is just a form of wings melding into the fuselage.

Composites are not invisible to EMR and never has been. Composites, Titanium and Aluminium have the ability to absorb EMR and that's about it. Just that composites have a higher degree of absorption. It is not some magical plate.

There is a thread on 5th gen technologies and stealth explained in our forum. Read it and it will at least give you a slight idea on how EMR works.

@Damian

Stealth is not relative to size. The B-2 is said to have a RCS that of a bumble bee. The F-22 is said to have an RCS that of a marble or even a bird's beak. The new bomber the Americans are planning which will be bigger than the B-2 will have an RCS 10 times smaller than a mosquito making it even more stealthy than the F-22.

Only design defines stealth. Very little is known about the J-20's stealth capabilities and the Chinese are going to keep it that way. They will peddle their hardware to Pakistan and have them proclaim how awesome they are. That's about it.
 

p2prada

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It's a flawed assessment and they themselves say it.

The fact is the test they used needs accurate dimensions of the aircraft. Even those are unavailable today.

What the Simulation Does Not Demonstrate

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;

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;

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;

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;

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 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.

The PO computational algorithm performs best where the product of wave number and dimension ka ≥ 5, where k ≈ 2πf [Table 5.1 in (1)], yielding errors much less than 1 dB. Knott cites good agreement for cylinders as small as 1.5 wavelengths in diameter1.
The simulator does not account for a number of environmental factors, such as air density profile at the aircraft skin boundary layer, thermal variations in absorbent material properties, and moisture precipitation. RCS contributions from these sources are negligible for the principal lobe magnitudes studied.
Also this;

The latter underscores the difficulty in attempting to perform highly accurate numerical RCS modelling of foreign airframe designs, where access to high fidelity shaping data, surface feature data, and materials type and application is actively denied.
The assessment gives a good figure for J-20 without actually studying the most RCS relevant criterias like back scattering, nose, engine inlets, panel joints, gaps and fastners etc. More importantly it does so at normal angles of incidence, meaning it has taken only front, back, top, bottom and sides for the assessment. So, everything that is supposed to give higher returns has been rejected. ROFL!
 

Kunal Biswas

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Do you mean honeycomb structure like pyramidal RAM in Anechoic chamber ? for that hostile radar wavelength should be smaller than the distance between two pyramids or diameter of hexagon. If hostile radar is emitting radiation at 10 GHz , then its wavelength would be 3 cm , so having surface with roughness little over 3 cm like Anechoic chamber on surface of combat aircraft is impossible. RAM manufacturer can't really assume what kind radar hostile side going to use. wavelength has to be equal to or smaller than visible light, and military radars uses far greater wavelength so this is not option. Another option is to convert radar energy in to heat energy, it possible up to certain extend, because, such RAM applied surface would already heated up due air-friction during flight. so RAM may not work effectively. (correct me,if I m worng).
That Depends on the current tech or even oldies, Technology are developing every day, A stealth deign based on many layers one so does one supporting other in unknown configuration, Material used and made from different substance are well tested for all kind of effects that may effect the deign, Further testings before production are made on different altitude and speed also different terrain, this gives an Idea how a stealth aircraft is made, Also we assume based on available info but that is just a raw assumptions..

Here are few technologies that are used over a stealth Aircrafts in layer conflagration:


ELASTOMERSView attachment 4087


Used for EMI and RCS reduction, elastomeric absorbers are available in a wide range of base materials for use in different environments. Products are based on magnetic or dielectric fillers and offer narrow, dual, triple or wide-band performance.
FOAMS

Rigid polyurethane or syntactic foams. foams are manufactured with graded loss for wide-band absorption or uniform loss for use in multi-layer absorbers.


COATINGS

View attachment 4089


Microwave absorbent coating system for use on composite or metallic structures.


HONEYCOMB


A light weight, wide-band radar absorber which can be manufactured in a range of configurations.



STRUCTURAL RAM



Structural radar absorbing components can be produced using a wide range of manufacturing techniques including wet lay-up, vacuum bag, resin infusion and resin transfer moulding. A range of reinforcement fibres can be used, depending on the application.


Frequency selective materials


Design and manufacture of frequency selective materials (FSS) structures for radomes and adaptive stealth.
Even this all dosent make any stealth degin 100% Invisible, though making out the composition of different alloys at different parts of an stealth aircraft is impossible unless i am the one is the designer, Engineer and Metallurgist..
 
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AprilLyrics

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This is only OBOGS problem, I know that people like theories that there are bigger problems but only problem is with OBOGS, nothing else. Besides this F-22A's will probably be all upgraded to latest Block upgrade, this can be another reason why they will not be used so long.

And yes, proper redesigning and problems solving will take time.
no matter what problem.the license of F-22 avaitors' r going to be Revocated.that means it is a big problem that more than 100 f-22s r staying on the ground for months.

Oh you committed blasphemy. How dare you pick up on the Chinese on Pak forum? Did you get banned for it?

Still, the title is inappropriate
what if i open a new thread about J-20 here even there has been one?
 
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