Chengdu J-20 5th Generation Aircraft News & Discussions

[j20blackdragon]

Slight update to Huitong's site.

It's now the J-21.

J-21

A scale-down model of J-21 was unveiled by the 601 Institute at the first International UAV Innovation Grand Prix held in Beijing in September 2011. It was first rumored in April 2011 that 601/SAC are developing a 4th generation medium multi-role stealth fighter as J-21. The aircraft has a conventional design featuring twin engines and DSIs similar to both American F-22 and F-35. The prototype could initially be powered by the 8.5t class WS-13 turbofan but later by the new 9.5t class "medium thrust" engine. A full-scale metal model may have been built in early 2011. The first prototype has been under construction since late 2011. First flight was projected to be in September 2012. J-21 is expected to be promoted at the international market as well as a low-cost alternative to American F-35.

- Last Updated 2/24/12

Chinese Military Aviation | China Air Force

 

[gambit]

You're telling me you can't see the saw-toothed edges on the F-117? Does the T-50/Pak-Fa IRST probe look like a giant radar-reflecting globe to you or a two-dimensional saw-toothed edge?

I swear, your eyes are terrible.

My visions, physical and intellectual, are superior to yours. Those saw-tooth structures are called 'geometric absorbers' and they are still physically larger than an X-band transmission. If they can deny the seeking radar reflections, what make you think the IRST device structure is not doing the same?

Like I said before, you are way over your head about this.

 

[Martian2]

My visions, physical and intellectual, are superior to yours. Those saw-tooth structures are called 'geometric absorbers' and they are still physically larger than an X-band transmission. If they can deny the seeking radar reflections, what make you think the IRST device structure is not doing the same?

Like I said before, you are way over your head about this.

Do you remember when we were discussing the reason for a shaped nose (like a duck bill) to make a plane stealthy? FYI, fourth-generation non-stealthy fighters have a general non-stealthy aircraft nose. Can you dig up your old citation that round objects, like the T-50/Pak-Fa IRST probe, are good radar reflectors? It will bolster my argument. Thanks.

 

[gambit]

The T-50/Pak-Fa IRST probe is about the size of a pilot's head. What do you think will happen to a plane's radar signature when you stick a pilot's helmet on the plane's nose (like an IRST probe)? That's right. It's a giant radar reflector. You really are totally clueless.

In radar detection, paradoxical as it sounds, because of the 10-lambda rule, the larger the spheroid structure, it may be appear smaller to the seeking radar. Now go and look up my explanation of the 10-lambda rule.

 

[gambit]

Do you remember when we were discussing the reason for a shaped nose (like a duck bill) to make a plane stealthy? FYI, fourth-generation non-stealthy fighters have a general non-stealthy aircraft nose. Can you dig up your old citation that round objects, like the T-50/Pak-Fa IRST probe, are good radar reflectors? It will bolster my argument. Thanks.

You are mistaken. All structures are radar reflectors or 'contributors'. The issue is how much the receiver is 'receiving' those reflections. It is clear by now that you have not understood a single thing I explained.

 

[Martian2]

HowStuffWorks "How does stealth technology work?"

"How does stealth technology work?
...
Most conventional aircraft have a rounded shape. This shape makes them aerodynamic, but it also creates a very efficient radar reflector. The round shape means that no matter where the radar signal hits the plane, some of the signal gets reflected back:
..."

Three posts ago, Gambit was arguing the T-50/Pak-Fa IRST probe is like a two-dimensional saw-toothed edge and is therefore stealthy. Do you agree with him? Or does the T-50/Pak-Fa IRST probe look like an excellent round radar reflector to you?

Gambit also tried the ridiculous "threshold" argument. Until I pointed out the IRST probe is clearly larger than 2.5cm (or 1 inch). The guy annoys me with his absurd arguments.

That's it folks. I'm tired of debunking the crackpot. Maybe we'll do it again on another night. Gambit, get some glasses for your eyes and more importantly, get a brain.

 

[gambit]

HowStuffWorks "How does stealth technology work?"

"How does stealth technology work?
...
Most conventional aircraft have a rounded shape. This shape makes them aerodynamic, but it also creates a very efficient radar reflector. The round shape means that no matter where the radar signal hits the plane, some of the signal gets reflected back

Some. But the same can be argued even for an angled plate because of microscopic surface discontinuities. These are called 'specular' reflections and if the cumulative energy level is below a certain threshold, specular reflections off a curvature can be irrelevant.

Three posts ago, Gambit was arguing the T-50/Pak-Fa IRST probe is a saw-toothed edge and is therefore stealthy. Do you agree with him? Or does the T-50/Pak-Fa IRST probe look like an excellent round radar reflector to you?

Did I? This make you a liar.

Your problem is obvious: That you are incapable of integrating disparate items into a single coherent idea.

 

[gambit]

Gambit also tried the ridiculous "threshold" argument.

Looks like you got caught in a hole of your own digging. The threshold argument is not 'ridiculous', unless we are talking about 'Chinese physics'. A threshold may be arbitrary but at least it set a goal or a standard. Clutter rejection is a threshold and it can be removed/discarded/disregarded. However, once that happens, the system is overwhelmed with data that it cannot process. That is why we have a 'clutter rejection' threshold in the first place.

Until I pointed out the IRST probe is clearly larger than 2.5cm (or 1 inch).

So are the serrations on the F-117's and J-20's panels. They certainly are much larger than cm. Now explain to us how are those serrations and the T-50's IRST device are NOT surface discontinuities.

The guy annoys me with his absurd arguments.

And we are amused by your stupidity.

 

[ptldM3]

The first thing you notice is that the SAIC stealth fighter has a frameless bubble cockpit canopy. For stealth, this is superior to the radar-reflecting metal-framed cockpit canopy on the T-50/Pak-Fa third prototype.

You will also notice the SAIC fighter has gold-colored RAM on the cockpit canopy. After two years, Sukhoi has failed to show a single picture of the T-50/Pak-Fa with gold-colored transparent RAM.

Some plastic toy now has a gold canopy? Since you are so critical of Russian aircraft and constantly claim that they have an inability to create a gold canopy than explain the Mig-31BM. And who set a criteria that says you need a so called gold canopy? The F-35 does not have a gold canopy and either does the SU-35, nor does the SE, and I don’t recall any gold canopies on the F-117 or B-2.

Thirdly, the SAIC design is superior to the Sukhoi T-50/Pak-Fa, because the Chinese fighter does not have a radar-reflecting protruding IRST.

You were jumping up and down with your miniskirt and pom-poms cheering that the WZ-10 is ‘stealthy’ even though it had a FLIR that is probably 5 times larger than the IRST found in the pak-fa. Not only that but the WZ-10 had countless 90 degree angles which violates the fundamental principle of ‘stealth’.

You are still shamelessly avoiding answering or explaining yourself with the comments you made about the WZ-10, and it’s easy to see why. There also appears to be a sort of a spherical object right above the F-117’s nose.

Unlike the T-50/Pak-Fa, the fuselage area behind the cockpit drops off quickly to meld into the main fuselage. This means greater stealth, because less radar energy will be reflected from a side illumination.

You made a lot of stupid comments in the past and this is no different. Even if the pak-fa’s fuselage behind the cockpit sits higher than many comparable aircraft it makes up for it with a flat fuselage. The J-20 may not have much of a ‘bump’ behind the canopy but its side profile is large, it would probably take two pak-fa’s stacked one upon the other to equal the side profile of the J-20. In other words the J-20 is a fat pig.

 

[gambit]

HowStuffWorks "How does stealth technology work?"

"How does stealth technology work?
...
Most conventional aircraft have a rounded shape. This shape makes them aerodynamic, but it also creates a very efficient radar reflector. The round shape means that no matter where the radar signal hits the plane, some of the signal gets reflected back:

This goes to prove how stupid you really are. Your source give only a PARTIAL explanation on how 'stealth' is possible. But what you brought on really clinched your ignorance and stupidity because the J-20 has more curvatures than angled facetings. So if we go by your argument, the J-20 is not 'stealthy' at all. Other than the blimp, no aircraft is completely rounded. That is why your source is good only for GENERAL understanding.

Go back to your playgrounds, CDF and Sino, where the other gullible Chinese will swallow uncritically whatever you say. People here are already exposed to the truth.

 

[laowai]

the reason why he's been posting here is because he's been kicked out of SDF, or rather removed himself

and while you're at it, please get off your high horse, there are far many more knowledgeable people out there, your presence here to play around with these kids only show your standards

 

[Martian2]

the reason why he's been posting here is because he's been kicked out of SDF, or rather removed himself

and while you're at it, please get off your high horse, there are far many more knowledgeable people out there, your presence here to play around with these kids only show your standards

For the record, I'm currently a senior member of SDF (who has never received a warning or infraction). Similarly, I am a senior member here. I've never been kicked out of anywhere. Whether I choose to post my insights or not, it is my decision.

Across all forums, I have approximately 1.5 "thanks" for every one of my posts. People recognize quality.

Gambit only has himself to blame for making ridiculous arguments. I caught him and now he's embarrassed.

1. In post #1587, he raised the "threshold" argument. When I challenged him by mentioning that X-band has a wavelength of 2.5 (one inch) to 4cm, he quietly withdrew his goofy "threshold" argument.

2. In post #1589, he tried to use 2-D saw-toothed edges to illustrate the possibility of a stealthy IRST probe. This Jedi mind trick only works on clueless members. I called him on his b.s. and put up a citation that large round 3-D objects, like the T-50/Pak-Fa IRST probe, are excellent radar reflectors.

Moral of the story: Don't try to b.s. your way into arguing the T-50/Pak-Fa IRST probe is stealthy. It is not. Raising non-applicable analogies will only draw my withering fire and a citation to prove you wrong. You'll look like an idiot. You have only yourself to blame for trying to pull a cheap trick.

[Note: Quite frankly, I enjoy debating Gambit when he's at his best. However, when Gambit tries to pull a fast one, I will call him on it. That is not why I'm here.

Sooner or later, Gambit will demonstrate a deeper knowledge in some niche area that I find useful. I have a lot of respect for Gambit when he's objective. I find him annoying when he's playing politics and twisting arguments to achieve a political end. Unlike him, I always try to stick to the facts.]

 

[Firemaster]

@ Martian
What will j20 be having for passive detection if IRST is so non stealthy
just curious

 

[Martian2]

@ Martian
What will j20 be having for passive detection if IRST is so non stealthy
just curious

As I had mentioned in the Pak Fa/FGFA thread, one possibility is to recess the IRST equipment into the airframe. That is hard to do on the T-50/Pak-Fa, which is mostly based on the non-stealthy Su-30 MKI airframe.

 

[Firemaster]

As I had mentioned in the Pak Fa/FGFA thread, one possibility is to recess the IRST equipment into the airframe. That is hard to do on the T-50/Pak-Fa, which is mostly based on the non-stealthy Su-30 MKI airframe.

not the whole aircraft just the gap between air intakes
, and nacelles