Chengdu J-20 5th Generation Aircraft News & Discussions

[SQ8]

Really..

Let me call Kopp... He busy these days testing J-20 RCS in the special optical chamber with some China boys.

Would like posters here to SPECULATE the weight of J-20..

Yes... pretty similar to his earlier nonsense on Russian radars and their superiority.
Unless the J-20 is built from steel.. One could speculate something close to the weight of a tornado or F-111.

 

[SQ8]

Really..

Let me call Kopp... He busy these days testing J-20 RCS in the special optical chamber with some China boys.

Would like posters here to SPECULATE the weight of J-20..

Yes... pretty similar to his earlier nonsense on Russian radars and their superiority.
Unless the J-20 is built from steel.. One could speculate something close to the weight of a tornado or F-111.

 

[ptldM3]

AIRSHOW-UPDATE 1-Pentagon F-35 chief blasts Boeing comments | Reuters

That post you just posted confirmed what i have been saying, that the Silent Eagle had the same frontal RCS as the F-35.

Next time read your sources

 

[j20blackdragon]

That post you just posted confirmed what i have been saying, that the Silent Eagle had the same frontal RCS as the F-35.

Next time read your sources

Boeing's claim has always been that the F-15SE was comparable in frontal RCS to a "dumbed down" (their words not mine) version of the F-35 being sold to foreign countries.

But I have a couple of questions for you or anyone else who feels like answering:

1. Do we know for sure that there is a "dumbed down" version of the F-35?

2. How does Boeing know the RCS of the F-35 to begin with?

3. Does anyone honestly believe that an aircraft designed in the 60s with modifications is somehow comparable in frontal RCS to a purpose-built stealth fighter that is still in development?

 

[gambit]

ty More Question's Coming
In Other Forums Members says That A plane to be stealth must be designed "as flat as possible" (like b-2) BUT Here I have a doubt.....flat surface reflects more radar energy compared to curved or saw tooth surface Right ?

Depends on the 'angle of approach' or 'incident angle' or variations of the phrasing. But essentially...

Pay attention to the third illustration.

The further away from perpendicular, the less energy is reflected back to the seeking radar. On the other hand, if your structure is two angled plates joined together to form a 'corner reflector', then it is just as bad as if you have a single plate that is perpendicular to the seeking radar, as in illustration 1.

Pre F-117 aircrafts are filled with 90deg 'corner reflectors' as illustrated above. So if you must have a 'corner reflector' avoid forming a 90deg structure. That is why 'stealth' aircrafts must either have no vertical stabilators at all, like the B-2, or have twin canted vertical stabs like the F-117, F-22, and the F-35. Note that that SR-71 and the F-18 have their vertical stabs in non 90deg configuration.

 

[gambit]

But I have a couple of questions for you or anyone else who feels like answering:

Sure.

1. Do we know for sure that there is a "dumbed down" version of the F-35?

The public may not, but there are NO technical barriers in creating an 'inferior' version of the F-35, in both avionics and radar observability, in other words, we can produce an export version of the F-35 that is 'dumber' than the US version and with a higher RCS.

2. How does Boeing know the RCS of the F-35 to begin with?

People talk as in 'shop talk'.

3. Does anyone honestly believe that an aircraft designed in the 60s with modifications is somehow comparable in frontal RCS to a purpose-built stealth fighter that is still in development?

Frontal RCS is tactically more important than other aspect angles. It make logical sense. If an aircraft is in the frontal view, it mean he is approaching you and if he is military aircraft, you should assume he is hostile unless assured otherwise. But after he delivered his missiles or bombs and exit the area, then how 'fat' is his behind, EM-speaking, to you is less important to him than his exit speed, which would probably be the proverbial 'balls to the wall' throttle setting. So to answer your question: Yes, it is possible to reduce the frontal RCS of a 1970s era fighter like the F-16 or F-16 or F-18 to very close as that of the F-35. It would take a lot of work but it is 'doable'. Keep in mind that the F-16 is the one that set the official unofficial standard for 'stealth'.

 

[ptldM3]

Boeing's claim has always been that the F-15SE was comparable in frontal RCS to a "dumbed down" (their words not mine) version of the F-35 being sold to foreign countries.

But I have a couple of questions for you or anyone else who feels like answering:

1. Do we know for sure that there is a "dumbed down" version of the F-35?

You really are confused aren’t you? Boeing has claimed that the Silent Eagle’s RCS is equal to export versions of the F-35, by ‘dumbed down’ the guy at Lockheed probably is refering to the export model of the F-35. Get it?

2. How does Boeing know the RCS of the F-35 to begin with?

Boeing is also involved in the F-35 development.

3. Does anyone honestly believe that an aircraft designed in the 60s with modifications is somehow comparable in frontal RCS to a purpose-built stealth fighter that is still in development?

I believe what Boeing says over what some magazine editors or armchair generals say.

 

[nafsiati]

Does China have thrust vectoring technology like russians or americans?

 

[gambit]

Does China have thrust vectoring technology like russians or americans?

So far: No.

You should understand that on any aircraft, from the WW I biplane era to today's modern jets, the engine is the component with the highest concentration of moving parts that create an environment with harshness equal to that of a smelting furnace. Not everyone can produce a modern Mach capable jet engine. Do that before start talking about thrust vectoring.

 

[Wet Shirt Contest]

ty More Question's Coming
In Other Forums Members says That A plane to be stealth must be designed "as flat as possible" (like b-2) BUT Here I have a doubt.....flat surface reflects more radar energy compared to curved or saw tooth surface Right ?

Look Carefully.....B2 FLAT is it ?

B2 uses a triangle frontally and a serrated trailing edge however it uses continuos curvature, it has been smoothed to a degree it becomes aerodynamically efficient, contrary to the Older Generation Stealth Design Like F-117 with its anti-aerodynamic multi faceted fuselage and airfoils, the continous curvature adds aerodynamic efficiency and scatters radar waves away at different directions but following the leading edge swept of the flying wing. Flattened things have small cross sections, the B-2 Stealth Bomber have been minimized to a degree the amount of radar reflections is decreased as the aerodynamically cross section has.

Although The ideal shape of an stealth aircraft is a rhombus (2D)

Well a (3D) would be Something like pyramid , first stealth aircraft like F-117 used a a multi facet diamond shaped fuselage that scattered radar waves at several directions F-117 Pic Below

 

[S10]

Does China have thrust vectoring technology like russians or americans?

They had technology demonstrator set up in the early 2000's. It's been 10 years since then, so I imagine they have at least made some progress. As far as a operational TVC goes, not yet.

 

[artaxerces]

How is it a big disappointment? Did you get to fly it? Did you get your hands on some classified information’s? What you think is irrelevant, your eye-ball test is irrelevant, and you preconceived and false notions of aerospace design is irrelevant. The pak-fa far exceeds all other known fighter aircraft in range, speed, ect. I would hardly call that a disappointment. I would not call the avionics in the pak-fa a disappointment either.

Hongwu, ptldM3, and Martian2

I wouldn't call the PAK-FA a disappointment just yet. In fact, I would warn against underestimating the capabilities of Russian fighter design teams. We have to remember that China's military aircraft industry is built on the foundation of Soviet technical expertise. The Mikoyan and Yak design bureaus basically trained the founding engineering teams at SAC, CAC, and XAC.

We know that the Pak-Fa will outclass just about any 4.5 Gen fighter by a substantial margin. The best 4.5 Gen fighter (Eurofighter) has a clean configuration RCS of about 1m^2, loaded with weapons, it would have a much larger RCS. A fully loaded Pak-FA, if we take the words of news reporters as gospel, would have an RCS of only 0.5 m^2.

With that said, I don't think a direct aircraft to aircraft comparison between the J-20 and the PAK-FA is very useful. It is way more instructive, imho, to understand the role that each aircraft intends to play in the overall operational doctrine. It might well be that Pak-FA is less stealthy than the J-20. But the real question to ask is why that design choice was made? It would be very foolish for us to assume that the Russians didn't do it because they couldn't.

Stealth comes with a cost. Extreme levels of stealth drastically increases the cost per aircraft. The ultra-stealthy skin on an F-22 takes 30 hours of maintenance effort to sustain 1 hour of flight time. If the J-20 is shooting for F-22 levels of stealth, I suspect that similar problems would be encountered.

If the Pak-FA is indeed less stealthy, it might also be cheaper to produce, cheaper to maintain. It might have a MUCH higher level of operational readiness than the J-20. It will likely have superior engines. It might even have superior avionics.

The point here is that in a real shooting war, stealth is not the only factor to consider.

 

[Tracy]

Look Carefully.....B2 FLAT is it ?

B2 uses a triangle frontally and a serrated trailing edge however it uses continuos curvature, it has been smoothed to a degree it becomes aerodynamically efficient, contrary to the Older Generation Stealth Design Like F-117 with its anti-aerodynamic multi faceted fuselage and airfoils, the continous curvature adds aerodynamic efficiency and scatters radar waves away at different directions but following the leading edge swept of the flying wing. Flattened things have small cross sections, the B-2 Stealth Bomber have been minimized to a degree the amount of radar reflections is decreased as the aerodynamically cross section has.

Although The ideal shape of an stealth aircraft is a rhombus (2D)

Well a (3D) would be Something like pyramid , first stealth aircraft like F-117 used a a multi facet diamond shaped fuselage that scattered radar waves at several directions F-117 Pic Below

Thanks Wet-Shirt Context and Gambit your post are very informative, i'll ask more questions later 1st let me absorb this.
from where you guys get this info ?

 

[ChineseTiger1986]

Hongwu, ptldM3, and Martian2

I wouldn't call the PAK-FA a disappointment just yet. In fact, I would warn against underestimating the capabilities of Russian fighter design teams. We have to remember that China's military aircraft industry is built on the foundation of Soviet technical expertise. The Mikoyan and Yak design bureaus basically trained the founding engineering teams at SAC, CAC, and XAC.

We know that the Pak-Fa will outclass just about any 4.5 Gen fighter by a substantial margin. The best 4.5 Gen fighter (Eurofighter) has a clean configuration RCS of about 1m^2, loaded with weapons, it would have a much larger RCS. A fully loaded Pak-FA, if we take the words of news reporters as gospel, would have an RCS of only 0.5 m^2.

With that said, I don't think a direct aircraft to aircraft comparison between the J-20 and the PAK-FA is very useful. It is way more instructive, imho, to understand the role that each aircraft intends to play in the overall operational doctrine. It might well be that Pak-FA is less stealthy than the J-20. But the real question to ask is why that design choice was made? It would be very foolish for us to assume that the Russians didn't do it because they couldn't.

Stealth comes with a cost. Extreme levels of stealth drastically increases the cost per aircraft. The ultra-stealthy skin on an F-22 takes 30 hours of maintenance effort to sustain 1 hour of flight time. If the J-20 is shooting for F-22 levels of stealth, I suspect that similar problems would be encountered.

If the Pak-FA is indeed less stealthy, it might also be cheaper to produce, cheaper to maintain. It might have a MUCH higher level of operational readiness than the J-20. It will likely have superior engines. It might even have superior avionics.

The point here is that in a real shooting war, stealth is not the only factor to consider.

Worthless opinion, how can they have better avionics when our AESA is superior than theirs?

 

[ptldM3]

Worthless opinion, how can they have better avionics when our AESA is superior than theirs?

No, your opinion is worthless. You have no details on either AESA's.