J-20 5th Gen Fighter Thread VI

[Brumby]

That does not mean those cascading effects can’t be designed away.

Except that wasn't the point of the entire conversation.

emm, you seem to have a problem understanding of modeller design in engineering, they did a very, very standard research practice in academic in almost all scientific/engineering areas all over the world (I don't know how to stress this stronger), eliminating all the other factors, and focus on the topic of this paper "Research on impact of canard to RCS"

You are right I am not into engineering modelling design because my background is entirely in the corporate world where I primarily deal with reality and all pieces of data - not disjointed pieces.

The problem is the research conclusion is based on an imagined design that does not exist in the real world. If you think relying on imaginary stuff is sound I have no further comments.
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[stannislas]

Except that wasn't the point of the entire conversation.



You are right I am not into engineering modelling design because my background is entirely in the corporate world where I primarily deal with reality and all pieces of data - not disjointed pieces.

The problem is the research conclusion is based on an imagined design that does not exist in the real world. If you think relying on imaginary stuff is sound I have no further comments.
.

fair enough, well, with the computer power explosively increasing in the last couple of decades, most of the current day design in engineering, from microchip design to bridge construction are done by computer simulation. And it might surprise you, after 1996, even nuclear weapons were designed entirely based on computer by major nuclear counties.

 

[latenlazy]

Except that wasn't the point of the entire conversation.

Your point was that because there are consequences to slapping on canards those consequences must assuredly be manifest, and inescapable.

You are right I am not into engineering modelling design because my background is entirely in the corporate world where I primarily deal with reality and all pieces of data - not disjointed pieces.

The problem is the research conclusion is based on an imagined design that does not exist in the real world. If you think relying on imaginary stuff is sound I have no further comments.
.

So many corporate types love bragging about how well they understand the world and only deal with reality and data without a single day's serious work on any of the details that would be necessary to actually comprehend and interpret what their data and observations mean. I surely hope you are not one of those people.

 

[AndrewS]

Except that wasn't the point of the entire conversation.



You are right I am not into engineering modelling design because my background is entirely in the corporate world where I primarily deal with reality and all pieces of data - not disjointed pieces.

The problem is the research conclusion is based on an imagined design that does not exist in the real world. If you think relying on imaginary stuff is sound I have no further comments.
.

In the entrepreneurial world, relying on imaginary stuff and disjointed pieces of data is essential.
Otherwise no one would ever have a vision of what is possible to create.

And it is those companies that seize the future, and become corporate giants.

 

[Brumby]

Your point was that because there are consequences to slapping on canards those consequences must assuredly be manifest, and inescapable.

The cascading effect is frankly secondary (and unknown) plus whether the fallout is manageable is even further downstream from the conversation. My primary point is that isolating the research into simplistic silo is just fundamentally problematic in its underlying logic.

So many corporate types love bragging about how well they understand the world and only deal with reality and data without a single day's serious work on any of the details that would be necessary to actually comprehend and interpret what their data and observations mean. I surely hope you are not one of those people.

There is nothing new under the sun. Sound decision making is premised not on data but meaningful information. If the underlying data is grounded on assumptions that are questionable the consequent information is suspect. .

 

[Inst]

-50 dBsm is XVLO territory. Even the F-35 is credited with only -30 dBsm overall. A rivet is probably much lower but that would be highly misleading. LOL. A stealth design has many moving parts and the eventual design would reflect tradeoffs. Isolating the conversation unto a specific variable can be highly misleading.

You can perfectly see the charts; the minimum RCS on the canards in the paper is around -50 dBsm. The F-35, according to some studies, can hit -50 dBsm in some quadrants and frequencies.

 

[siegecrossbow]

-50 dBsm is XVLO territory. Even the F-35 is credited with only -30 dBsm overall. A rivet is probably much lower but that would be highly misleading. LOL. A stealth design has many moving parts and the eventual design would reflect tradeoffs. Isolating the conversation unto a specific variable can be highly misleading.

-50 dBsm is probably from a few optimized angles.

 

[Brumby]

You can perfectly see the charts; the minimum RCS on the canards in the paper is around -50 dBsm. The F-35, according to some studies, can hit -50 dBsm in some quadrants and frequencies.

Can you please quote your source referencing -50dBsm as admittedly I have never seen such low numbers. The difference between -50 and -30 dBsm is a magnitude of 100 times and that is not trivial.


-50 dBsm is 100,000 times more stealthy than a F-18E/F and the F-18 is the US most stealthy 4th generation platform.

 

[Inst]

Can you please quote your source referencing -50dBsm as admittedly I have never seen such low numbers. The difference between -50 and -30 dBsm is a magnitude of 100 times and that is not trivial.
View attachment 55983

-50 dBsm is 100,000 times more stealthy than a F-18E/F and the F-18 is the US most stealthy 4th generation platform.

First:

Single-figure RCS is an extremely ambiguous measurement of an aircraft's stealthiness. For instance, the Russians can correctly claim that the F-22 has a -10 dBsm RCS by averaging a polar diagram of the F-22's RCS.

Even when you have a polar diagram, that's not good enough. A polar diagram only accounts for one azimuth, and moreover, it usually accounts for only one frequency band as well.

When you go through the multi-azimuth polar diagram and then go through frequency, you still have remaining ambiguities. For instance, what's the functional RCS of the aircraft; i.e, stealth aircraft tend to have complex emissions control systems that maintain a specific angle toward detection platforms. What is the practical RCS against one radar? Against five? Against twelve?

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Second, -10 dBsm typically accounts for a 44% decrease in detection range. A variance of -20 dBsm from the listed figure only results in a reduction of radar range by 68%, although it can reach 99% if jamming is effective.

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Third, the actual stealth level of the F-35 is an unknown. Some sources claim that the F-35 is stealthier than the F-22 due to improvements in material. Others claim it's less stealthy.

The minus 50 dBsm comes from a Chinese RCS study of a F-35 model at about 10 Ghz, which people have argued is flawed (in the sense of being biased against the F-35) due to the intake shaping. That's the minimum RCS seen, so the F-35, if its emissions control and detector positioning permits, can reach -50 dBsm.

 

[by78]

Re-posting lost high-resolution images.