Re: anticopyists:

Then what design elements are original in the J-31/21? The J-20 has an unique Canard – Lerx – Delta configuration thats shared only by the Rafale, and the Rafale doesn’t have the same V tailfins + anhedral dihedral mix, but the J-31 is really really close to copy-pasting a F-22 back onto a F-35 front + wings between F-35 and F-22 size.

The word copy doesn’t really bother me as we all know it’s meant in the context of “similar shape”. I don’t think anyone seriously believes the idea that china supposedly hacked enough information from LM to somehow reverse engineer their own F-35.

But if this is a precedent for calling something a copy then every other medium weight stealth fighter under consideration can be considered a copy of F-22/F-35 as well.

Not to mention all the flying wing stealthy UCAVs under development must be copies of each other.

ATD-X as far as being a copy goes is more similar to the J-20 in that it looks like a stealthified F-2 with less aggressive shaping compared to the true fifth-generation stealth aircraft.

“Yeah but it’s really really close to resizing an F-22 to F-35 size! It is basically a copy — there are no original design elements!
And don’t get me started on AMCA and KFX!”

Now you can assume that they started with an F-35 and took everything “suboptimal” away, or you can assume they started from scratch and simply ended up with a similar design because the laws of physics dictate their design preferences under a strict set of requirements.

^ This

This is pretty much an F-35 copy, but there are a few differences.

First, the wing loading on the J-21 is lower than on the F-35 A and B variants, although not the C variant, with a larger wing for its size.

Unlike the F-35, the J-21 does not have bumps on the bottom to optimize its aerodynamic characteristics. This should improve all-aspect stealth slightly, but we don’t know how good the Chinese are at stealth optimization in general.

I thought the presence of F-35’s bumps was to accommodate avionics and larger weapon bays due to lack of internal space?
That is to say, everything else being equal (RAM etc), no bumps is superior to having bumps for VLO?

The tailfins are larger on the J-21 than on the F-35, on a proportionate basis. This should increase stability somewhat, but will contribute to higher RCS.

With regards to complaints about rear-stealth, the great thing about the J-21 is that it’s a twin-engine design with the potential for optimization for all-aspect stealth. If you’re complaining about unstealthy exhausts, you can always swap them for 2D TVC once the technology is available.

Technically there’s nothing stopping a single engined fighter being equipped with a flat nozzle.

Also, inb4 Carlos Kopp complains that the J-21 is what the F-35 should have been.

Hehe you did so for carlo kopp but bill sweetman beat you to it.

1)why they use dual landing wheels on the front landing gear, and there is some distance between the 2 wheels obviously, if they need to reinforce they front landing gear strength to make it more suitable for carriers and short/poor runways, why dont just reinforce the structure instead of adding more wheels.

infact if the plane dosen’t have a very low landing speed (like transports or civil airliners), the distance between the 2 front wheels will cause they landing very dangerous( the plane will roll sidways).

2) the engines are for show, the designer put much thoughts on the head and continues to ignore the rear, the baisc ideas for J-20/F60 is the same: very stealthy when you are going in for a strike, but dont show your ass on your way back, it looks very fat and sexy for enemy radars.

3) details, it’s like a Iranian or North Korean design, great efforts to stay in fasion, but still a crude idea, no avionics installed yet, like a design made by a bunch of undergraduates.

You realize everything you said could be applied to T-50 as well? :p

I doubt it is smaller by volume or weight.

It also looks void of engines.

It is quite a bit smaller by volume and weight.

J-20 won the J-XX heavy weight fighter competition.

This thing is a medium weight fighter, most likely for navy, or to supplement J-20.

J-20 2002 spotted??!

A few things to note.
CAC usually allocates the second number of a prototype as static test frames. Clearly this plane isn’t a static test frame.
You can also see a bump behind the canopy (avionics?)
On the more close up picture you can spot a strip of grey indicating what I presume to be the split between the radome and the rest of the nose. Finally there’s the change in position of the nose probe. I’m wondering if there is a radar behind that radome, because even though the nose probe is in that position, other planes exist with similar probes and radars behind it (J-10A, for one).
Of course I’m only entertaining that possibility because everyone’s been saying this plane was supposed to be 2003, making me wonder if there is already a J-20 test frame (early last year, there was the question of the Al-31 equipped J-20 vs silver nozzle J-20 both numbered 2001? What if the Al-31 one was sent to be a static test frame?), and they just changed the numbering. This 2002 plane will still be the second flying prototype, and for CAC the second flying prototype usually fields avionics close to the real thing.

Anyway, just my thoughts. Toodles.

That picture was taken years ago, in the middle of the 2000s somewhere. The project’s ongoing and the plane is called Y-20, a heavy transport between Il-76 and C-17.

Y-9 is the modernized Y-8/An-12, what C-130J is to C-130

The chinese aviation community are eagerly waiting for pics of Y-20.

Among other reasons.

Via CDF, =GT

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