J-20 5th Gen Fighter Thread IV (Closed to posting)

[Skywatcher]

Let me make it simple for you in one statement: materials' contribution to RCS is least significant.

That has been made clear multiple times in a

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, which you now embarrassingly try to ignore by claiming it to be irrelevant.

The implication of this information is that your argument doesn't work, since your argument is based on an assumption that materials play a significant role. This information is thus very relevant.

Least significant does not mean not significant. The shaping did 90% of the work, but it is the RCS that does the last 10-5%? How hard is that to understand, really?

You can understand a lot about aircraft RCS by building a model yes. But in a high stakes scenario involving a very low margin of error (like the F-22, due to its low RCS), you have to understand the last 5-10% in order to build a working model, if you care about the lives of your mine.

Non sequitur. That particular method of stealth is obsoleted as a result of radar employing other frequencies. It has nothing to do with invention of AESA radar. This has also been mentioned in your own source.

Of which your thickness problem is addressed by RAM inserts.

Since whatever stealth technologies used by LM and CAC is likely indigenous developed (unless you think that the J-20 copies the F-22), NRIET trying to develop a detailed evaluation of the F-22's stealth characteristics, like the RAM coating, is like ONI trying to determine the acoustics on the 093B by looking at the LA class's powerplant. They operate on similar principles, but each system is unique.

Wrong. You can absolutely predict how the other guy's technology will behave, since laws of physics is the same to everybody.

In an ideal world yes, if you had access to perfect information about every bit of detail. But you don't.

Quoting something which I already know isn't going to make your arguments more correct. You have yet to provide proofs that estimating F-22's RCS requires reverse-engineering a physical aircraft.

You do have to "discover [sp] the technological principles of a device, object, or system through analysis of its structure, function, and operation" if you want to estimate RCS, which includes understanding how the subsystems interact with each other inside of hoping that Physics 101 and a vague internal document will magically solve all your problems. I take this to be a concession?

 

[Skywatcher]

And it is that final 5-0.01% that will be significant.

I think what engineer saying isn't incorrect, it is true that shaping determines the vast majority of an aircraft's RCS reduction, and China may be able to completely replicate the shaping of an F-22, but the difference between an F-22 with shaping and Chinese applied RAM and the difference between an F-22 with US RAM may be only a few square centimeters, however with today's radar technology that few square centimeters may be highly significant.

Continuing the F-15 analogy:
An F-22 without RAM may have a 95% reduced RCS compared to F-15
An F-22 stand in with Chinese RAM may have a 97.5% reduced RCS compared to F-15.
An F-22 built by lockheed may have a 99.5% reduced RCS compared to F-15 (due to say, better RAM, and some "minute" differences in structure and serration that add up)
So while the difference is "only" 2% between a test dummy and the real thing, it may not be operationally negligible due to the power of modern radar. Unless we know what that difference means in terms of say, detection and tracking ranges by modern PLA IADS, AEWC and fighter FCRs, we cannot definitively say whether the differential in test RCS and real RCS is practically significant.

In short: a 1950s radar may not be able to tell the difference between a "chinese" F-22 stand in and a lockheed F-22 (i.e.: it won't be able to detect either), but a modern 21st century AESA may be able to detect one at longer ranges than the other.

Exactly. Building a mockup of a MiG-31 to get its RCS is pretty much the entire process, but fifth generation fighters are a lot, lot more complicated (who cares if you go a few square inches over on a MiG-31 model?)

 

[Engineer]

Least significant does not mean not significant. The shaping did 90% of the work, but it is the RCS that does the last 10-5%? How hard is that to understand, really?

You can understand a lot about aircraft RCS by building a model yes. But in a high stakes scenario involving a very low margin of error (like the F-22, due to its low RCS), you have to understand the last 5-10% in order to build a working model, if you care about the lives of your mine.

You constantly try to portray that last few percentages to be a world of difference, but 5~10% is just that -- 5~10%. It means any error in estimating material properties by Chinese engineers only causes a 5~10% deviation. If the engineers underestimated the effect of RAM by half, then the model would still be 95~97.5% accurate. If the engineers got the estimation of the material effects right by 80%, than the estimation would be 98~99% accurate. That is why your argument doesn't work.

Of which your thickness problem is addressed by RAM inserts.

Since whatever stealth technologies used by LM and CAC is likely indigenous developed (unless you think that the J-20 copies the F-22), NRIET trying to develop a detailed evaluation of the F-22's stealth characteristics, like the RAM coating, is like ONI trying to determine the acoustics on the 093B by looking at the LA class's powerplant. They operate on similar principles, but each system is unique.

Strawman argument. No one ever claimed that the RAM on the F-22 is the exact same as that on the J-20, or that the 093B powerplant is the exact the same as the LA class's. Estimating RCS involves taking the country's existing knowledge of how stealth works, then applying them in a way to figure out how well the other guy's stuffs work.

In an ideal world yes, if you had access to perfect information about every bit of detail. But you don't.

The need for perfect details is an invention made by you. There is no such requirement in the real world.

You do have to "discover [sp] the technological principles of a device, object, or system through analysis of its structure, function, and operation" if you want to estimate RCS, which includes understanding how the subsystems interact with each other inside of hoping that Physics 101 and a vague internal document will magically solve all your problems.

Nope. Figuring out the RCS only requires application of one's scientific and practical implementation knowledge in stealth technologies to the exterior. It does not concern with the interactions among subsystems. There is no also need for a physical copy to exist for diss-assembly, copied, then have a perfect replica produced before any knowledge can be gained. See post #1874.

I take this to be a concession?

I will take this as your concession.

 

[Engineer]

Exactly. Building a mockup of a MiG-31 to get its RCS is pretty much the entire process, but fifth generation fighters are a lot, lot more complicated (who cares if you go a few square inches over on a MiG-31 model?)

Fifth generation fighters are indeed complicate, which is why only three countries in the world can realize them. China being one of those countries, and so has the abilities to figure out the RCS of a fifth generation fighter.

 

[Deino]

Are these new images ... or older ones ??

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Deino

 

[chuck731]

Fifth generation fighters are indeed complicate, which is why only three countries in the world can realize them. China being one of those countries, and so has the abilities to figure out the RCS of a fifth generation fighter.

Correction, only 3 countries have chosen to accept the trade off implicit in actually trying to field one.

I can name at least 2 more countries / consortiums whose basic technologicial and manufacturing capabilities had been and continue to be equal or superior to one, perhaps two of those 3 countries and would therefore certainly have been able to realize their own G5 fighters by now if they have chosen to accept the trade offs 15-20 years ago.

There are probably 3-4 others countries / consortiums that could realistically hope to have amassed the basic technologicial and manufacturing capabilities needed to field respectable G5 fighter significantly before the first G6 fighters make an appearence.

 

[Zool]

Correction, only 3 countries have chosen to accept the trade off implicit in actually trying to field one.

I can name at least 2 more countries / consortiums whose basic technologicial and manufacturing capabilities had been and continue to be equal or superior to one, perhaps two of those 3 countries and would therefore certainly have been able to realize their own G5 fighters by now if they have chosen to accept the trade offs 15-20 years ago.

There are probably 3-4 others countries / consortiums that could realistically hope to have amassed the basic technologicial and manufacturing capabilities needed to field respectable G5 fighter significantly before the first G6 fighters make an appearence.

Individual nations with the Technology Base and MIC to develop and manufacture their own 5th Gen are few. There are numerous sub-systems and component suppliers involved in fielding these aircraft. Economic Power / National Debt is also a key factor in the ability to start and finish the process.

The advantage and preference is always for an individual nation to design and build it's own premier aircraft when capable. It provides for absolute control over sensitive technologies, capabilities and the timetable for development and induction.

I would argue that JSF is not a consortium development but an American fighter whose cost and manufacturing of non-sensitive systems and software have been shared among a group of allied counties to offset the direct expense to the US and drive export sales. A true consortium aircraft would be the EuroFighter who's program, if you examine from genesis to today, demonstrates the challenges of a true joint effort.

Cheers,
Zool

 

[Jeff Head]

I can name at least 2 more countries / consortiums whose basic technologicial and manufacturing capabilities had been and continue to be equal or superior to one, perhaps two of those 3 countries and would therefore certainly have been able to realize their own G5 fighters by now if they have chosen to accept the trade offs 15-20 years ago.

There are probably 3-4 others countries / consortiums that could realistically hope to have amassed the basic technologicial and manufacturing capabilities needed to field respectable G5 fighter significantly before the first G6 fighters make an appearence.

If I realistically look at the nations capabilities I believe that any of the following "could" build a 5th generation fighter.

- United States
- Russia
- China
- Japan
- 2 or 3 of the following: UK, France, Germany, Sweden
- 3 or 4 of the following: Israel, Brazil, South Africa, India, ROC, S. Korea

Not likely to see a union/joint effort between any three of those last, but I believe together they could do it.

 

[chuck731]

I think the consortium and nations that has had the ability to have at least prototyped a G5 fighter by now but didn't yet choose to do so were Eurofighter consortium, France and Japan.

I think the following nations and consortiums has the ability to prototype of G5 fighter within the next 10 years, but could not have done so much sooner, are India, South Korea with or without Turkey and Indonesia, and Sweden.

I think following states could only get G5 fighter by buying or being junior partners in a consortium:
Turkey, Indonesia, Israel, Brazil, Taiwan.

 

[TerraN_EmpirE]

Photos on the web of a new missile on the rails of a J20.

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