Shenyang FC-31 / J-31 Fighter Demonstrator

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Hyperwarp said:

Assuming manufacturing techniques, RAM applied are on an equal basis, then the FC-31 might very well be slightly stealthier than the J-20. Remember it is smaller in size compared to the flanker sized J-20, and unlike the F-35, the FC-31 has a nice smooth belly. F-35 does not have a smooth belly like the F-22, FC-31 and J-20. But when it comes to the J-20 even if we disregard the canard issue, remember the J-20 has ventral fins. That mean 2 more added surface area. Despite the YF-23 not having the massive S-duct of the YF-22, overall the YF-23 was RCS wise considered marginally stealthier. The reason for that is the YF-22 had a conventional tail while the YF-23 had ruddervators.

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J-31 still has a relatively bigger vertical tail, and the J-20’s canards are still much smaller than the horizontal tails of the J-31. There’s a way you can argue this the other way around. This stuff is not visually obvious for a reason.

From the initial rumors the J-XX design was constantly redesigned due engine limitations. Allegedly, very early proposals by CAC didn't have a tail at all. It looked liked a flanker sized X-36. But they needed a very powerful engine with 3D-TVC flawlessly integrated with the FBW. The design slowly evolved to what is it today. This means no WS-15 and no TVC. Once the WS-15 and 3D-TVC are ready you'll see the J-20 go through quite a few changes. Fanboy in me hope it'll look like this -

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Where did you hear that from?

Hyperwarp said:

From the initial rumors the J-XX design was constantly redesigned due engine limitations. Allegedly, very early proposals by CAC didn't have a tail at all. It looked liked a flanker sized X-36.

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I second Latenlazy -- where did you hear that?


The only place on the internet where I've heard the idea of a "tailless" J-XX is Inst and his rather confusing constant expectation that there will one day be a tailless J-20.


But I have not read anything about a tailless J-XX concept, or a tailless J-20 concept or a tailless J-20 under development at all.

latenlazy said:

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Where did you hear that from?

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The tailless design? Those were very early rumors many years back before the the 1st flight.

Hyperwarp said:

The tailless design? Those were very early rumors many years back before the the 1st flight.

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I remember those years, and I only recall two major concepts that were seriously discussed -- one being a canard delta and one being a triplane configuration.

Both were described as having tails. Obviously the canard delta won and became J-20.


But I don't recall any rumours about a tailless design.

Hyperwarp said:

The tailless design? Those were very early rumors many years back before the the 1st flight.

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Yet we’ve had pictures of models that later proved to be quite accurate going back to the early 2000s which clearly show there was a tail.

Someone posted almost the pic of an exact version of the J-20 on CJDBY back in 2009

Bltizo said:

I remember those years, and I only recall two major concepts that were seriously discussed -- one being a canard delta and one being a triplane configuration.

Both were described as having tails. Obviously the canard delta won and became J-20.


But I don't recall any rumours about a tailless design.

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latenlazy said:

Yet we’ve had pictures of models that later proved to be quite accurate going back to the early 2000s which clearly show there was a tail.

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Again, I repeat "RUMORS"! This was before the early drawings.

RUMOR START:
PLAAF/CAC didn't want an F-22 equivalent. They wanted something better, stealthier, more maneuverable, etc. Simplest they had was a delta-canard with NO TAIL just like the X-36. But this concept required F119 class engines with 3D-TVC and a very mature FBW system. That proposal went down the toilet almost immediately. Slowly more control surfaces started getting added especially a tail, and the size of them also increased. They had experimented with canards similar the X-36, forward-swept canards, etc, etc finally settled with the current design. The core problem being the lack of F119 class engines with 3D-TVC.
RUMOR END:

You can take that with a mountain of....

Hyperwarp said:

Again, I repeat "RUMORS"! This was before the early drawings.

RUMOR START:
PLAAF/CAC didn't want an F-22 equivalent. They wanted something better, stealthier, more maneuverable, etc. Simplest they had was a delta-canard with NO TAIL just like the X-36. But this concept required F119 class engines with 3D-TVC and a very mature FBW system. That proposal went down the toilet almost immediately. Slowly more control surfaces started getting added especially a tail, and the size of them also increased. They had experimented with canards similar the X-36, forward-swept canards, etc, etc finally settled with the current design. The core problem being the lack of F119 class engines with 3D-TVC.
RUMOR END:

You can take that with a mountain of....

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Hmm there are "rumours" and then there are rumours.

For example, there are rumours which are widely circulated and which have some basis in reality, like as early as 2006/7 it was widely reported that a canard delta and a triplane configuration from CAC and SAC were being developed as a next generation fighter concept. Those rumours of course turned out to be true.


But I do not recall ever seeing widespread rumours of a tailless fighter at all, and certainly no information since then make me think such rumours were ever credible.


.... putting it another way, hyperwarp, who made the post that you quoted to begin with?

i.e.: who said this, where did it come from, and was the source considered to be credible in any form or was it just a random person on the internet --

"PLAAF/CAC didn't want an F-22 equivalent. They wanted something better, stealthier, more maneuverable, etc. Simplest they had was a delta-canard with NO TAIL just like the X-36. But this concept required F119 class engines with 3D-TVC and a very mature FBW system. That proposal went down the toilet almost immediately. Slowly more control surfaces started getting added especially a tail, and the size of them also increased. They had experimented with canards similar the X-36, forward-swept canards, etc, etc finally settled with the current design. The core problem being the lack of F119 class engines with 3D-TVC."

Bltizo said:

Hmm there are "rumours" and then there are rumours.

For example, there are rumours which are widely circulated and which have some basis in reality, like as early as 2006/7 it was widely reported that a canard delta and a triplane configuration from CAC and SAC were being developed as a next generation fighter concept. Those rumours of course turned out to be true...

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Off-course I remember those. Lets leave out SAC proposals. According to the
rumor/conspiracy theory (by me ), those were the more mature CAC concepts with available tech, requiring canards and tail. Tailless design was something earlier that was dropped long before those.

Bltizo said:

...But I do not recall ever seeing widespread rumours of a tailless fighter at all, and certainly no information since then make me think such rumours were ever credible.


.... putting it another way, hyperwarp, who made the post that you quoted to begin with?

i.e.: who said this, where did it come from, and was the source considered to be credible in any form or was it just a random person on the internet --

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I totally understand the skepticism. Unfortunately, who said it and where I do not recall. This was around or before CAC was selected in 2008. At least 10-years ago I would say. That was the 1st person who showed me a sketch of a possible JXX concept that turned out to be fairly close. Didn't think much of it back then. But thinking about it now makes sense to me that CAC initial aimed very high but due to limitations the realistic design came to fruition.

Hyperwarp said:

I totally understand the skepticism. Unfortunately, who said it and where I do not recall. This was around or before CAC was selected in 2008. At least 10-years ago I would say. That was the 1st person who showed me a sketch of a possible JXX concept that turned out to be fairly close. Didn't think much of it back then. But thinking about it now makes sense to me that CAC initial aimed very high but due to limitations the realistic design came to fruition.

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Well since you don't remember who it was, we'll have to speculate. You don't visit Chinese forums because you're not Chinese so in 2008 you must've heard from a foreigner who drew up a tail-less delta concept. Considering the J-20 project had only just begun in 2008, the likelihood of a foreigner's accurately predicting genuine concepts studied within a brand new fighter program initiated by a country renowned for secrecy is low, very low.