Chengdu J-20 5th Generation Aircraft News & Discussions

[Su33KUB]

View attachment 581627


In fact, the monostatic or backscatter RCS depends on the following

• Target geometry
• Target material composition, especially for the surface
• Position of radar antenna relative to target
• Angular orientation of target relative to radar antenna
• Frequency of the electromagnetic energy
• Radar antenna polarization.

The aim is always the same: reflect the radar energy to certain, irrelevant directions, and thus keeping the (monostatic) RCS low.

4.2 Radar absorbing materials
4.4 Active cancellation

the common problem in forums and why they become so uncivilized is consider an aircraft an extension of our own ego, the reason J-20 has DSI is not stealth, it is maintenance, F-22 has in the intake need for more maintenance, maintenance, reflects the numbers of sorties it will fly, to put it simple the DSI intakes give to the J-20 a relatively a very low RCS but more important allows it will fly more often than F-22, in time of war more reliability means more sorties, so the DSI allows to both the J-20, J-10, F-35 less maintenance, however this limits the aircraft to an ideal air pressure recovery for a speed of Mach 1.6, of course the aircraft can fly faster even Mach 2 or even more, but by lowering air pressure recovery acceleration suffers because the aircraft will not be able to go beyond an ideal Maximum thrust of a static jet engine rig , in few words flame outs, the engine will reduce max thrust between 8% in an ideal lose to 20% thus never achieving its max thrust.


To summarize has DSI for more reliability with relatively the same RCS, same is F-35, just consider the ideally flat surfaces direct the radar EM waves in a single direction, bulges and the DSI is one, will send it within 180 degrees albeit weakened, bulges have relatively speaking an sphere type scattering however they are a bit different.


He is not wrong, F-22 has diffraction grating in its intake, so they add RAM, due to a more complex structure due to the bleed and bypass systems., but pretty much is very stealthy, but J-20 has one that assure more reliability, F-22 might not fly due to RAM and maintenance issues on the intakes, J-20 might not suffer such problems it will fly more often and more sorties, but ideally it will fly between 1.6-1.8 Mach.

The F-22 has a very complex multi shock ramps in its caret type intakes that allow good pressure recovery at Mach 2+


If you can not see that each technology offers advantages and disadvantages this conversation will become a fight of egos, all technologies prioritize advantages but also suffer disadvantages

 

[vi-va]

the common problem in forums and why they become so uncivilized is consider an aircraft an extension of our own ego, the reason J-20 has DSI is not stealth, it is maintenance, F-22 has in the intake need for more maintenance, maintenance, reflects the numbers of sorties it will fly, to put it simple the DSI intakes give to the J-20 a relatively a very low RCS but more important allows it will fly more often than F-22, in time of war more reliability means more sorties, so the DSI allows to both the J-20, J-10, F-35 less maintenance, however this limits the aircraft to an ideal air pressure recovery for a speed of Mach 1.6, of course the aircraft can fly faster even Mach 2 or even more, but by lowering air pressure recovery acceleration suffers because the aircraft will not be able to go beyond an ideal Maximum thrust of a static jet engine rig , in few words flame outs, the engine will reduce max thrust between 8% in an ideal lose to 20% thus never achieving its max thrust.


To summarize has DSI for more reliability with relatively the same RCS, same is F-35, just consider the ideally flat surfaces direct the radar EM waves in a single direction, bulges and the DSI is one, will send it within 180 degrees albeit weakened, bulges have relatively speaking an sphere type scattering however they are a bit different.


He is not wrong, F-22 has diffraction grating in its intake, so they add RAM, due to a more complex structure due to the bleed and bypass systems., but pretty much is very stealthy, but J-20 has one that assure more reliability, F-22 might not fly due to RAM and maintenance issues on the intakes, J-20 might not suffer such problems it will fly more often and more sorties, but ideally it will fly between 1.6-1.8 Mach.

The F-22 has a very complex multi shock ramps in its caret type intakes that allow good pressure recovery at Mach 2+


If you can not see that each technology offers advantages and disadvantages this conversation will become a fight of egos, all technologies prioritize advantages but also suffer disadvantages

To be stealthy, you need to control both RCS and thermal radiation. Flying at Mach 2.0 is much easier to be detected.

Nowadays, infrared detector array is much more advanced than the era when F-22 was born. To be stealthy, you can't fly too high at 20000 m, you can't fly too low at 3000 m. Most likely 6000-7000 m. The speed should be lower than 1 Mach, or a little bit higher than 1 Mach. Otherwise, it will be detected from a further distance.

As I said above, it's an arbitrary statement, we knew little about how J-20 is designed, nor F-22. No one can claim which is more stealthy at all. J-20 was designed 20 years later after F-22, there are a lot of new technologies J-20 can use while F-22 may or may not used.

 

[gambit]

The red cycled area is the strongest reflection of F-22 by your theory. What is worst, the reflection direction is straight forward, which should be avoid.

So let us look at this graphic again...

Are you telling this forum that the classic diverter plate intake design on the F-22 produced that great of a contrast of a voltage spike compared to the newer DSI 'bump"?

Are you telling us that?

If you are saying so, give us supporting data.

The flaw in your feeble understanding of post 11837 page 790 (mine) is evident.

Your rule has huge flaws. Here are the rules I copied from the paper below(page 138), which was published on Journal of Computations & Modelling, vol.4, no.1, 2014, 129-165

Very good. Let us look at them...Remember, the red comments are YOURS...

In fact, the monostatic or backscatter RCS depends on the following

• Target geometry
• Target material composition, especially for the surface
• Position of radar antenna relative to target
• Angular orientation of target relative to radar antenna
• Frequency of the electromagnetic energy
• Radar antenna polarization.

The aim is always the same: reflect the radar energy to certain, irrelevant directions, and thus keeping the (monostatic) RCS low.

4.2 Radar absorbing materials
4.4 Active cancellation

Low Observable Principles, Stealth Aircraft and Anti-Stealth Technologies
http://www.scienpress.com/Upload/JCM/Vol 4_1_9.pdf

This is my theory...Which is not really mine to start, but only what I learned from being in the field and active duty...

- Control of QUANTITY of radiators
- Control of ARRAY of radiators
- Control of MODES of radiation

Target geometry -- this falls under under rule 2.

Target material composition -- -- this falls under under rule 2.

Position of radar antenna relative to target -- this falls under under rule 2.

Angular orientation of target relative to radar antenna -- this falls under under rule 2.

Frequency of the electromagnetic energy -- this falls under under rule 2.

Radar antenna polarization -- this falls under under rule 2.

What you do not understand is that the radar cross section (RCS) value of any body is a FICTITIOUS number. It is 'fictitious' not in the sense that we make it up but 'fictitious' in the sense that the value changes according to how the seeking radar and the body are in physical relation to each other.

Take rule one: Control of QUANTITY of radiators.

If the F-22 is viewed from the rear aspect, Rule One is in effect to the seeking radar. In other words, the seeking radar cannot calculate what it cannot see. The F-22's intake did not physically disappeared from the jet. The seeking radar just simply cannot see the intakes and if it cannot see them, it cannot calculate the RCS value at that time. If we turn the F-22 around so that the seeking radar can 'see' the jet's intakes and calculate them, then we will have a new RCS value, hence the context of the word 'fictitious' and how Rule One is supported in principle and in actual math.

The contexts of the word 'control' are thus:

- What the target physically have
- What the seeking radar can actually 'see'

Each context affects the other.

This is why your dismissal of the the three rules indicates your ignorance of ALL the relevant subjects, starting with basic radar detection principles all the way to understanding how low radar observable bodies are designed.

Do you see post 11866? Everything in that post support the three rules. You are just too arrogant to admit to your ignorance.

You have no clue what radar absorbing materials J-20 and F-22 used, you don't know what active cancellation technologies J-20 and F-22 used neither.

Neither jet have active cancellation.

Active cancellation is for another debate but for now -- am willing to bet your ignorance on that subject is even worse than what we have seen so far.

But just for curiosity sake, for either passive or active cancellation, which rule is it?

You don't know J-20 and F-22 radar design which is crucial for RCS deduction.

We can see that at least I know far better than you and your Chinese friends -- COMBINED.

To be stealthy, you need to control both RCS and thermal radiation.

Control? Very good. Now you are learning.

Flying at Mach 2.0 is much easier to be detected.

Nowadays, infrared detector array is much more advanced than the era when F-22 was born. To be stealthy, you can't fly too high at 20000 m, you can't fly too low at 3000 m. Most likely 6000-7000 m. The speed should be lower than 1 Mach, or a little bit higher than 1 Mach. Otherwise, it will be detected from a further distance.

Clue for you, buddy...

Being low radar observable does not give license to be careless. When I was active duty and on the F-111, we trained on how to 'read' the radar warning receiver (RWR) output to avoid detection and still penetrate defended airspace. We were good enough at it -- with 1960s tech -- that the Soviets had no effective defense against the UK based F-111s. That helplessness was confirmed by Adolf Tolkachev and you can look him up.

As I said above, it's an arbitrary statement, we knew little about how J-20 is designed, nor F-22. No one can claim which is more stealthy at all. J-20 was designed 20 years later after F-22, there are a lot of new technologies J-20 can use while F-22 may or may not used.

Hey...Your fellow Chinese on this forum made physics defying claims since the J-20 came out. I just debunked them.

 

[Su33KUB]

To be stealthy, you need to control both RCS and thermal radiation. Flying at Mach 2.0 is much easier to be detected.

Nowadays, infrared detector array is much more advanced than the era when F-22 was born. To be stealthy, you can't fly too high at 20000 m, you can't fly too low at 3000 m. Most likely 6000-7000 m. The speed should be lower than 1 Mach, or a little bit higher than 1 Mach. Otherwise, it will be detected from a further distance.

you can consider J-20 first an element of weapons system, China had some limitations and also advantages, J-20 was designed pretty much like a Large F-35, adding very likely better manoeuvrability due to its canards, if it has similar wing loading and TWR.

If it has better engine very likely will super cruise, thus you can consider it a F-35 on steroids, it has wider and larger weapons bays, comparable avionics with probably better radar in terms of power, but the laws of physics do not change, Gambit is not wrong, RAM and Composite materials have limits and radars advance too, speed is very important regardless, F-22 has also disadvantages, its maintenance is expensive, but it is fast, very fast without afterburner , speed allows dodge missiles, I know fans think J-20 has no flaws, it does like any aircraft you can consider that China is addressing that in a new 6th generation fighter, but so are other powers, it is the dynamics of the arms race, but pretty much J-20 is a 5th generation fighter and with the aid of J-11s and J-10s will balance the chess game of the air for China, the 5th generation aircraft have flaws too, they are expensive, have low reliability, high maintenance, low numbers of production, and long development so long some countries already will skip it to go directly to the 6th generation, and most of these aircraft need TVC nozzles to fix poor aerodynamics result of too much stealth, they are more tools of propaganda and national pride, but i can consider J-10 will continue production for at least 15 years more due to the low production numbers of J-20 and J-31.


J-20 will act more like a stealth AWACS guiding drones and J-11s and only entering combat if other stealth fighters are in the area or advanced SAMs are deployed, but as weapon you have to consider cruise missiles and ballistic missiles are to fill up for the flaws China might have in its air force.

regards

 

[LKJ86]

Via @超侧卫 from Weibo

 

[Ultima Thule]

speed allows dodge missiles

How Can it outmaneuver the missile traveling at Mach-4+ and F-22 is super cruising at 1.6/1.8 Mach, and also by the agility F-22 can't evade a missiles maneuvering at 40-50 G whereas F-22 has a max agility of 11 G, the only way to defeat air to air missiles are ECM/EW/Chaff and flare not speed or maneuverability @Su33KUB

 

[gambit]

Over the yrs, a lot of noise were produced by the ignorant about the supposedly 'non-stealthy' classic diverter plate intakes of the F-22 vs the supposedly more 'advanced' diverterless DSI 'bump' on the J-20. The problem for the ignorant is that the ideal angle that will allow the seeking radar to have unrestricted view of the intakes are nearly tactically non-existent, meaning that direct head-on aspect angle exists mostly in exercises.

Here is a more realistic view as 'seen' by any seeking radar in actual tactical combat situations...

Where are the F-22's intake diverter plates now?

Instead, what we and the seeking radar 'sees' are major protrusions from the J-20:

- Two wings
- Two canards
- Two rear stabs
- Two engine exhausts
- Two intakes

Total of ten major radiators.

Remember the three rules in designing a radar low observable body...

- Control of QUANTITY of radiators
- Control of ARRAY of radiators
- Control of MODES radiation

From this more tactically common aspect angle, the J-20 as 'seen' by a seeking radar is less obedient than the F-22 to Rule One: Control of QUANTITY of radiators.

The F-22's classical intake diverter plates and the J-20 newer DSI 'bumps' are unseen by the seeking radar, therefore, mathematically irrelevant in calculating a temporary radar cross section (RCS). So instead of the F-22's classical diverter plates, the seeking radar 'sees' the J-20's prominent intake structures.

This is real physics, not 'Chinese' physics.

 

[Ultima Thule]

Over the yrs, a lot of noise were produced by the ignorant about the supposedly 'non-stealthy' classic diverter plate intakes of the F-22 vs the supposedly more 'advanced' diverterless DSI 'bump' on the J-20. The problem for the ignorant is that the ideal angle that will allow the seeking radar to have unrestricted view of the intakes are nearly tactically non-existent, meaning that direct head-on aspect angle exists mostly in exercises.

Here is a more realistic view as 'seen' by any seeking radar in actual tactical combat situations...

Where are the F-22's intake diverter plates now?

Instead, what we and the seeking radar 'sees' are major protrusions from the J-20:

- Two wings
- Two canards
- Two rear stabs
- Two engine exhausts
- Two intakes

Total of ten major radiators.

Remember the three rules in designing a radar low observable body...

- Control of QUANTITY of radiators
- Control of ARRAY of radiators
- Control of MODES radiation

From this more tactically common aspect angle, the J-20 as 'seen' by a seeking radar is less obedient than the F-22 to Rule One: Control of QUANTITY of radiators.

The F-22's classical intake diverter plates and the J-20 newer DSI 'bumps' are unseen by the seeking radar, therefore, mathematically irrelevant in calculating a temporary radar cross section (RCS). So instead of the F-22's classical diverter plates, the seeking radar 'sees' the J-20's prominent intake structures.

This is real physics, not 'Chinese' physics.

So why you're using DSI intakes on F-35 if its bad for Stealth @gambit

 

[onebyone]

https://twitter.com/x/status/1178655404705775618

 

[vi-va]

So why you're using DSI intakes on F-35 if its bad for Stealth @gambit

well put.

@gambit , you are too arrogant. Nowadays, BVR dominate, instead of dog fight. J-20 don't have machine gun, that can demonstrate something.

2 bird in 200 kilometer away, which angle is most important? The straight forward position. F-35 use DSI intakes, don't tell me US technology move backward in recent years.

 

[Ultima Thule]

well put.

@gambit , you are too arrogant. Nowadays, BVR dominate, instead of dog fight. J-20 don't have machine gun, that can demonstrate something.

2 bird in 200 kilometer away, which angle is most important? The straight forward position. F-35 use DSI intakes, don't tell me US technology move backward in recent years.

Even today net centering warfare no Jets whether its stealth or not, don't hide much from long range ground based Radars/AWACS/ Fighter jets AESA @viva_zhao
And don't engage @gambit he is known for its anti Chinese statements because he is VIETNAMESE-AMERICAN @viva_zhao

 

[vi-va]

Even today net centering warfare no Jets whether its stealth or not, don't hide much from long range ground based Radars/AWACS/ Fighter jets AESA @viva_zhao
And don't engage @gambit he is known for its anti Chinese statements because he is VIETNAMESE-AMERICAN @viva_zhao

you are right. It's system vs system, not bird vs bird.

Even in 2 birds vs 2 birds scenario, it's not just which one is more stealthy, it's electronic warfare vs electronic warfare.

Any any scenarios, AEW&C is more and more important.

 

[gambit]

well put.

@gambit , you are too arrogant. Nowadays, BVR dominate, instead of dog fight. J-20 don't have machine gun, that can demonstrate something.

2 bird in 200 kilometer away, which angle is most important? The straight forward position. F-35 use DSI intakes, don't tell me US technology move backward in recent years.

This is why I enjoy debating you guys so much -- you do not think.

Nowhere did I even implied that the DSI design is 'bad' for a low radar observable body. The DSI 'bump' does not make up the intake itself. It is a COMPONENT of the entire intake SYSTEM. The DSI 'bump' follows the intake design no matter where the intake is positioned on the aircraft, like how this F-16 was modified to have the DSI intake system.

http://aviationintel.com/fast-history-lockheeds-diverterless-supersonic-inlet-testbed-f-16/

As far as beyond visual situations goes, my post 11875 demonstrate exactly such a situation.

Arrogant? You should go look in the mirror. I am a USAF veteran, F-111 (Cold War) then F-16 (Desert Storm). What do you have? As far as I am concerned, you are not allowed to use the word 'bird' in talking about jets. Such language is reserved for those who have actually been directly involved in aviation, which am quite certain you do not qualify.

 

[vi-va]

This is why I enjoy debating you guys so much -- you do not think.

Nowhere did I even implied that the DSI design is 'bad' for a low radar observable body. The DSI 'bump' does not make up the intake itself. It is a COMPONENT of the entire intake SYSTEM. The DSI 'bump' follows the intake design no matter where the intake is positioned on the aircraft, like how this F-16 was modified to have the DSI intake system.

http://aviationintel.com/fast-history-lockheeds-diverterless-supersonic-inlet-testbed-f-16/

As far as beyond visual situations goes, my post 11875 demonstrate exactly such a situation.

Arrogant? You should go look in the mirror. I am a USAF veteran, F-111 (Cold War) then F-16 (Desert Storm). What do you have? As far as I am concerned, you are not allowed to use the word 'bird' in talking about jets. Such language is reserved for those who have actually been directly involved in aviation, which am quite certain you do not qualify.

I drive car, doesn't mean I know how to make cars, nor how to evaluate which car design is better. Especially when the car you never touched, such as J-20.

None of us here knew J-20 much, just some pictures, which means nothing.

 

[gambit]

I drive car, doesn't mean I know how to make cars, nor how to evaluate which car design is better. Especially when the car you never touched, such as J-20.

None of us here knew J-20 much, just some pictures, which means nothing.

Big difference between you and I...

Stick time...

https://www.urbandictionary.com/define.php?term=Stick Time
Time behind a joystick; flight time, flying time.

I have it. You do not. I have civilian flight training even before my USAF time. My technical understanding of radar detection as a field test engineer was after the USAF. Basically, I designed field tests to detect 'low altitude autonomous flight vehicles' aka 'drones' in both how to detect them and how they can avoid detection.

Bottom line, you know shit.