J-20... The New Generation Fighter III

tell you what Martian, we are more than happy to discuss anything about the J-20, what is that A bulge, what is this B curve, is it that long or short, is the J-20 painted pink in the inside

but the moment you bring other aircraft for comparison, be it F-22, PAK FA or freakin Thunderbirds, it's a pissing contest

Martian, I respect your posts and attempts to analyse things that are, frankly, quite complex, so I am not criticizing, only asking:

In your diagram of radar entering the inlet of the F-22, the radar waves enter straight into the inlet. (I am foregoing the obvious fact that the S-ducts are curved and not faceted). You make the claim that this creates only 2 reflections to hit the compressor blades, and 4 to exit. I think that there is a lot more going on here than what you suggest, but for analysis purposes, we should keep it simple.

Now, in the J-20 diagram the radar waves enter the inlet at an angle, which is, of course, going to necessitate more reflections for the radar to reach the compressor blades.

The point I am trying to make is, why are you insinuating that the DSI bump automatically restricts all radar waves to enter the inlet at an angle? The DSI does not prevent all radar waves from entering the inlet straight on (like in your F-22 diagram). Or am I wrong? Furthermore, the absence of DSI on the F-22 does not automatically mean that all radar waves will enter straight on...they could still come in at an angle and require just as many reflections to reach the compressor blades as in the J-20.

Martian said:

J-20 Mighty Dragon Air Dominance Stealth Fighter

J-20 banks left and looks for prey.

[Note: Thank you to HouShanghai and Feiyang 彬彬有礼 for the picture.]

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J-20 Mighty Dragon eats non-supercruise fighters for lunch

J-20 Mighty Dragon and F-22 Raptor have the best planform alignment

Definitions and Terminologies:

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The J-20 Mighty Dragon edge alignment for its main wings and canards has only five different sweep angles (e.g. red, green, orange, yellow, and blue).

The F-22 matches the J-20 in edge-alignment design for its main wings and rear horizontal tailplanes. The F-22 also has a total of only five different sweep angles (e.g. red, green, orange, yellow, and blue).

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The Pak Fa/T-50 has the worst edge-alignment design for its main wings and rear horizontal tailplanes. The Pak Fa/T-50 has a massive total of 11 different sweep angles (e.g. addition of pink, light blue, purple, dark red, black, and white).

In conclusion, the Pak Fa/T-50 cannot match the stealthiness of the planform alignment design of the main wings and winglets for the J-20 and F-22. With an extra six different sweep angles, the Pak Fa/T-50 is clearly more detectable by radar in many more directions.

[.]

Click to expand...

SAMs that kill stealthy fighters and jammers that Jam stealth fighters
[video=youtube;1GcAUaLrPNU]http://www.youtube.com/watch?v=1GcAUaLrPNU&feature=player_embedded[/video][video=youtube;u3vQfh-QwwQ]http://www.youtube.com/watch?v=u3vQfh-QwwQ&feature=BFa&list=PL23B5DB5E4D94B411&lf=mh_lolz[/video]

are cylinders less stealthy than flat surfaces?

In this context it should also be noted that a flat plate focuses its backscattering
on a very narrow angular sector, with a high RCS value.
A sphere, by contrast, has a low RCS value which is uniform at all angles.
Thus, on a limited angular sector around the specular direction, spheres
and cylinders give the lowest RCS values. If otherwise, RCS must be kept
low on a wide angular sector, then it is better to use very narrow-beam
shapes such as the flat plate, correctly aimed in order to avoid the specular
flash [7].

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The corner reflector has an RCS almost as
high as the flat plate but over a wider angle,
i.e., over ±60E, the return from a corner
reflector is analogous to that of a flat plate
always being perpendicular to your
collocated transmitter and receiver?




J-20 flats nacelles only give a very big RCS when the radar is on a perpendicular direction to the radar, PAKFA nacelles have smaller RCS but are evenly distribute in more angular sectors



Square trihedral corner reflector Strongest radar return due to triple reflection of incident wave

Right dihedral corner reflector Second strongest radar return due to double reflection of incident wave; decreases from maximum slowly with changing θ and rapidly with changing φ

Flat plate Third strongest radar return due to direct reflection of incident wave; decreases rapidly as incidence angle changes from perpendicular

Right circular cylinder Strong radar return as aspect (θ) changes, but decreases rapidly as azimuth (φ) changes






Uploaded with




reflected signal from a tilted plate ...Real as the previous example. Unusual feature: the reflected energy is reflected in another direction. Well, the transmitting radar cannot receive this energy. Therefore there are bistatic radars at which the transmitter and the receivers are separated from each other spatially




similar to heliography, flat plates concentrate radar on one direction thus reducing RCS by returning very little energy back to the radar



There is a tremendous advantage to positioning surfaces so that the radar wave strikes them at close to tangential angles and far from right angles to edges, as will now be illustrated. To a first approximation, when the diameter of a sphere is significantly larger than the radar wavelength, its radar cross section is equal to its geometric frontal area. In the example shown in two accompanying figures, the return from a one- square-meter sphere is compared to that from a one-meter-square plate at different look angles. One case to consider is a rotat'on of the plate from with the radar beam at right angles to a pair of edges. The other is with the radar beam at 45 degrees to the edges. The frequency is selected so that the wavelength is about i/io of the length of the plate, in this case very typical of acquisition radars on surface-to-alr missile systems.

At normal incidence, the flat plate acts like a mirror, and its returns 30 decibels (dB) above or 1000 times the return from the sphere. If we now rotate the plate about one edge so that the edge is always normal to the incoming wave, we find that the crosssection drops by a factor of 1000, equal to that of the sphere, when the look angle reaches 3o degrees off normal to the plate. As the angle is increased, the locus of maxima falls by about another factor Of 50, for a total change Of 50,000 from the normal look angle.

Now if we go back to the normal lncl idence case and rotate the plate about a diagonal relative to the incoming wave, we see a remarkable difference. In this case, the cross section drops bY 3o dB when the plate is only 8 degrees off normal, and drops another 4o dB by the time the plate is at a shallow angle to the incoming radar beam. This is a total change in radar cross section of io million!





As we can see round nacelles are not as unstealthy as people think, cylinders actually reduce RCS and if you apply booms like in the F-35, the boom is actually canted reducing RCS laterally leaving the nacelle relativelly stealthy because cylinders are only visible to radar only in some sectors but its reflectivity is reduced thus its RCS is reduced in all directions of its circunference.

The boom reduces radar reflections in the sector the cylinder reflects back to the radar the radiaton, leaving that angular sector stealthy.

Flat nacelles are very visible from some angular sectors and using triangulation detectable

all stealth fighters have angular sectors where they are more detectable, while flat nacelles are only detectable from a very narrow angular sector, its radar reflectivity is higher, cylinders reduce RCS in all directions but have equal reflectivity in all directions

So by using jamming, IRST and some stealth features that do not compromise aerodynamics PAKFA achieves better performance and equivalent RCS reductions and the same pplies to F-35.

Oh no. I detect shitstorm.

Martian, meet Mig-29

i respectfully request a thread cleaning

Good day

Due to the incessant complaints to my 2 posts on the J-20, which are the only ones that I have made in the last few months, I will take another long vacation and let you chat among yourselves. It is ridiculous how much you guys complain at my few posts.

I made one post on planform alignment. I made another post on air-inlet stealthiness. Since many of you believe that your chattering posts are of more value, I will leave you to keep chattering among yourselves and take my insights elsewhere.

You have given me an unpleasant reminder of why I left in the first place. My views cannot be shouted down. I will make more YouTube videos in the next few months on stealth technology. Over 82,000 people have viewed my first J-20 video. Tens of thousands of people will also see my future videos on stealth technology. Your complaints are pointless and ineffective.

Re: Good day

Martian said:

Due to the incessant complaints to my 2 posts on the J-20, which are the only ones that I have made in the last few months, I will take another long vacation and let you chat among yourselves. It is ridiculous how much you guys complain at my few posts.

I made one post on planform alignment. I made another post on air-inlet stealthiness. Since many of you believe that your chattering posts are of more value, I will leave you to keep chattering among yourselves and take my insights elsewhere.

You have given me an unpleasant reminder of why I left in the first place. My views cannot be shouted down. I will make more YouTube videos in the next few months on stealth technology. Over 82,000 people have viewed my first J-20 video. Tens of thousands of people will also see my future videos on stealth technology. Your complaints are pointless and ineffective.

Click to expand...

Or maybe we don't ascribe value to either your posts or our own. It's a discussion, not an award ceremony.

Your contribution is much appreciated, but that doesn't mean we can't discuss or critique the content you present. You don't have to take it personally. It's really not about shouting down your views or complaining, but about assessing the information that's presented. No one is foolproof, and any healthy discussion will have points and counterpoints.

Re: Good day

Martian said:

Due to the incessant complaints to my 2 posts on the J-20, which are the only ones that I have made in the last few months, I will take another long vacation and let you chat among yourselves. It is ridiculous how much you guys complain at my few posts.

I made one post on planform alignment. I made another post on air-inlet stealthiness. Since many of you believe that your chattering posts are of more value, I will leave you to keep chattering among yourselves and take my insights elsewhere.

You have given me an unpleasant reminder of why I left in the first place. My views cannot be shouted down. I will make more YouTube videos in the next few months on stealth technology. Over 82,000 people have viewed my first J-20 video. Tens of thousands of people will also see my future videos on stealth technology. Your complaints are pointless and ineffective.

Click to expand...

You'll be the second to take a vountary "vacation" then, with airsuperiority being the first though he did so to study. In this case a certain word comes to mind which starts with e and ends with go perhaps? I kidd.

But in all seriousness we're not shouting you down, just assessing what you're writing. It might be easier for you if your analyses weren't in a mini thesis format.

But okay, good day to you as well

I suppose my questions about the angle at which radar enters inlets will go unanswered. I was just respectfully,asking how he came to his conclusion. Critique and questioning should be welcomed, not treated with contempt.

Martian has left us mere mortals to toil amongst ourselves while he watches us knowing full well that he, and only he, is correct.

This forum is unique in that many of the people who inhabit it are rather educated. If one posts something that does not make sense...someone else will point it out. If one cannot handle critique or disagreement, they shouldn't be here.

Anyways, back to the topic.