Shenyang J-21/31/F-60/AMF thread part 1

[Inst]

It's a copy because many many features of the plane are similar to that of the F-35. Not all the details are right, but the overall aerodynamic structure is similar, and we know the Chinese have broken into Lockheed and pilfered their design data.

This is not to say the Chinese didn't do their own work on the aircraft, used their own supercomputers to run simulations, and made their own design decisions, but in large part this is an F-35 with twin engines, a larger wing, and better project management (although that's not saying much).

[TR1]

J-31 = 0.9 x F-35 ?

I am not big fan of F-35, but LOL!

Exactly, I am curious what the basis is for this conclusion.

[Inst]

35*.9 = 31.5 rounded down
22*.9 = 19.8 rounded up

[TR1]

Didn't even notice.

What I was more curious was, what determines this plane is 90% as capable as F-35? Details are non existent.

[mack8]

It's a copy because many many features of the plane are similar to that of the F-35. Not all the details are right, but the overall aerodynamic structure is similar, and we know the Chinese have broken into Lockheed and pilfered their design data.

This is not to say the Chinese didn't do their own work on the aircraft, used their own supercomputers to run simulations, and made their own design decisions, but in large part this is an F-35 with twin engines, a larger wing, and better project management (although that's not saying much).

Well, with all due respect you're contradicting yourself within your two phrases. A copy is pretty much something that is identical with an a original right ? Well , you might say K-13 is a copy of AIM-9B , or Tu-4 is a copy of B-29, and perhaps J-11 or J-16 may or may not be a copy of Su-27/30 ( depending if there was a proper deal/licence agreement or not), but to say J-31 is a copy of F-35 and/or 22 because it has "many similar features" that's way far fetched.

It may have similar features to either and have a similar configuration, and surely the chinese engineers studied the american fighters long and hard but it is NOT a copy. If it was something that would have been hard to recognize next to an F-22 or 35 then THAT can be called a copy. But J-31 is not a copy, sorry.

[Amiga500]

but in large part this is an F-35 with twin engines, a larger wing,

Do you have any idea of the design loops and completely different optimisations that will exist for just those two changes? Of course you don't, otherwise you wouldn't have posted such rubbish.

[Aurel]

Hey, the Chinese fixed the F-35. They are better at this than LM.

[andys]

Didn't even notice.

What I was more curious was, what determines this plane is 90% as capable as F-35? Details are non existent.

I was plucking figures out of the air dear boy, to illustrate a point. You either understand the point or you don't. And how anyone would honestly determine "how good X is compared to Y", given for example, the farce that was the USAF tanker contest of late...

[MSphere]

Do you have any basis that it is anywhere as capable in both performance and on-board systems?

I can say with absolute certainity that there are no onboard systems on the J-31 as we speak.

[TR1]

I can say with absolute certainity that there are no onboard systems on the J-31 as we speak.

But its near F-35 in capability11!!

[FalconDude]

But its near F-35 in capability11!!

better in fact.

[latenlazy]

It's a copy because many many features of the plane are similar to that of the F-35. Not all the details are right, but the overall aerodynamic structure is similar, and we know the Chinese have broken into Lockheed and pilfered their design data.

This is not to say the Chinese didn't do their own work on the aircraft, used their own supercomputers to run simulations, and made their own design decisions, but in large part this is an F-35 with twin engines, a larger wing, and better project management (although that's not saying much).

It seems both proponents and naysayers know so much about this new plane, and all from a picture! Superficial appearance does not a plane make. Where are all the people who accuse Airbus of copying Boeing?

And FYI, all these it must be a copy because China stole information accusations are presumptuously absurd. That stolen data could have been used for a number of purposes. China could have just as easily used stolen information on the F-35 to develop a counter rather than a copy, or use the stolen data as a foundation to innovate their own solutions. Stealing information for the sake of copying is about the poorest use of espionage.

[MSphere]

But its near F-35 in capability11!!

That depends on what they install in there. But based on pure looks I would not be surprised if this bird had better flying characteristics than the F-35 in the end (which is, let us admit, not that hard to achieve)..

The only thing we know for sure is the shaping of the aircraft. Everything else (materials, RCS, loadout, onboard systems, electronics..) is still a mystery.. In fact, most of that might not be defined / set up as of yet. That is why I don't understand what the whole fuzz about who's better is about.

But she's quite a looker, I must say. I like her a lot, much more than the J-20.

[Tigershark]

navy mig29 has no chance against j31 now that we confirm it is a navy aircraft

[Blitzo]

It's a copy because many many features of the plane are similar to that of the F-35. Not all the details are right, but the overall aerodynamic structure is similar, and we know the Chinese have broken into Lockheed and pilfered their design data.

This is not to say the Chinese didn't do their own work on the aircraft, used their own supercomputers to run simulations, and made their own design decisions, but in large part this is an F-35 with twin engines, a larger wing, and better project management (although that's not saying much).

I suppose we can immediately write off AMCA, ATD-X and KFX as copies as well...

[Inst]

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.

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.

And you really don't have to complain about the J-31 being somehow inferior to the F-35 as a copy. Most real innovation is based on copying other people's stuff and somehow getting it "wrong", but when you get it wrong, you have to innovate to overcome your failings. The J-31 didn't copy the F-35's suboptimal design decisions where a lift-fan had to be integrated; and the design looks stealthier than the F-35 due to not having to design all these bumps because of not being able to meet an overly ambitious design spec.

[TR1]

navy mig29 has no chance against j31 now that we confirm it is a navy aircraft

Naval MiG is in service, something the J-31 won't be sharing for years.

[latenlazy]

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.

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.

And you really don't have to complain about the J-31 being somehow inferior to the F-35 as a copy. Most real innovation is based on copying other people's stuff and somehow getting it "wrong", but when you get it wrong, you have to innovate to overcome your failings. The J-31 didn't copy the F-35's suboptimal design decisions where a lift-fan had to be integrated; and the design looks stealthier than the F-35 due to not having to design all these bumps because of not being able to meet an overly ambitious design spec.

I'm not complaining about the J-31 being better or worse than the F-35. We simply don't know. Pictures are pretty, but they don't tell us squat about the plane's performance. I'm pointing out how faulty the logic of "they stole information on the F-35 IT MUST BE A COPY" argument is. There is more than one way for stolen information to be used, of which copying is about the least useful option. AKA, that espionage is involved does not necessitate the conclusion that it must be a copy.

You're using a really poor qualifier by talking about planform. I could just as easily say the ATD-X looks like the F-22, because they share the exact same wing arrangement and look the same from the front and back. Hey look their inlet geometry is IDENTICAL. That would gloss over the more specific details in shaping though. For example, the J-31 and F-35 have the same general nose shape, but the J-31's nose is wider, and the faceting is at different angles. And note, there are only so many ways you can design a conical nose for an airplane. Again, where are the people accusing Airbus of copying Boeing.

Also, you yourself just said the F-31 didn't copy the F-35's "suboptimal" design preferences, which basically means the F-31 and the F-35 are different. 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. We won't know either which one is more true, but in the end both result in a statement that basically says the J-31 and J-35 are different, AKA not a copy. Think about that for a second.

[Blitzo]

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

[thinkplum]

First of all, i am a huge fan of F35. However, F35 project looks very bad on the balance sheets of LM, if i'm their auditor, i'm definitely suggesting impairment on captallized R&D cost (from futuristic cash flow perspective).

But...from realistic cash flow view, as long as LM can persuade US congress & millitary & other loser US alies binded under the purchase agreements, tax money will contue to flow in. Overall it's a good thing: it gives hope, and pays bread.

F60 seems to be more like a modernized 4 gen plane rather than a cost-effective 5 gen plane, with decent, not necessarily cutting-edge on-board systems, it will make a good and economical choice for low intensity A2A mission and high intensity A2G missions(judging from the landing gear doors F60 seems to have thicker armor, which also appears to be solid metal, than F20/F22/F35). And thus i doubt super cruise is in the design specs of this plane: weaker engines & the designer is not careful with weight.

[Inst]

My argument is primarily based on lineage; which is to say, an aircraft does not come into existence ex nihilo, but is based on existing aircraft because existing aircraft provide aerodynamic and design research aspects that can be built on for cheaper than coming up with a completely new planform.

The J-20 comes from the J-10, the F-22 is a stealthified and improved F-15, the PAK-FA is a stealthified Flanker.

When you copy an aircraft, what you're doing is that you're taking someone else's planform idea without descent from your own aircraft. It is very hard to copy because if you copy someone else's aircraft, you don't necessarily have the research data available to you so you don't benefit from their lineage. But in the Chinese case, they've broken into Lockheed, so copying the J-31 off the F-35 is a lot more viable than a bunch of hicks in the middle of nowhere trying to replicate an F-22 from photographs.

The reason I think the J-31 is a copy of the F-35 and F-22 is because Shenyang has no lineage with the planform concept in the J-31; it's traditionally worked with the J-11 and the J-31 doesn't look anything like the J-11. Shenyang's contender for the J-XX project was a triplane platform with canards, wings, and tailfins, and the J-31 doesn't resemble that at all. The closest planes to the J-31 are the F-22 and F-35 fighters.

===

The one other way to argue about it would be to say that the J-31 shows significant JF-17 lineage. The issue with that is that the JF-17 is Chengdu's, not SAC's, and I'm not sure how happy Chengdu would have been to transfer their old data on the JF-17 to their rivals in the Northeast.

[latenlazy]

My argument is primarily based on lineage; which is to say, an aircraft does not come into existence ex nihilo, but is based on existing aircraft because existing aircraft provide aerodynamic and design research aspects that can be built on for cheaper than coming up with a completely new planform.

The J-20 comes from the J-10, the F-22 is a stealthified and improved F-15, the PAK-FA is a stealthified Flanker.

When you copy an aircraft, what you're doing is that you're taking someone else's planform idea without descent from your own aircraft. It is very hard to copy because if you copy someone else's aircraft, you don't necessarily have the research data available to you so you don't benefit from their lineage. But in the Chinese case, they've broken into Lockheed, so copying the J-31 off the F-35 is a lot more viable than a bunch of hicks in the middle of nowhere trying to replicate an F-22 from photographs.

The reason I think the J-31 is a copy of the F-35 and F-22 is because Shenyang has no lineage with the planform concept in the J-31; it's traditionally worked with the J-11 and the J-31 doesn't look anything like the J-11. Shenyang's contender for the J-XX project was a triplane platform with canards, wings, and tailfins, and the J-31 doesn't resemble that at all. The closest planes to the J-31 are the F-22 and F-35 fighters.

===

The one other way to argue about it would be to say that the J-31 shows significant JF-17 lineage. The issue with that is that the JF-17 is Chengdu's, not SAC's, and I'm not sure how happy Chengdu would have been to transfer their old data on the JF-17 to their rivals in the Northeast.

By that logic, countless planes are copies of countless other planes. Su-27 shares the same pancake centerline as the Tomcat, and the same nose as the Hornet. Eurofighter, Rafale, and Gripen are all delta canards. If you want to use the word lineage, fine. But copy and lineage are two different things, and if we're using your loose definition of copy, then there's a lot of copying going on. This by the way completely glosses over how badly you're oversimplifying plane designs. Claiming the F-22 is a stealthified F-15 is alone indicative of just how faulty that logic of it's a copy because "they stole another's lineage" is. The F-22 wasn't even created by the same company as the F-15. Did Lockmart copy McDonnell Douglas's lineage? If so, where the hell is the YF-23's lineage? How come it doesn't look like the F-15 that preceded before it?

And yeah, China probably stole a crap-ton of information, but the J-XX competition that both CAC and SAC competed precede the cyber-espionage. SAC couldn't possibly have based their current design off their rejected design right? Or better yet, SAC couldn't possibly have chosen a basic aerodynamic configuration that everyone already knows about. Nope, using a basic configuration they haven't used before is totally impossible. They absolutely must follow their previous design philosophies for their new one. Can't try new things at all. So stupid they need to look at the F-22 and F-35 to realize you can stick tail planes on a main wing. Didn't learn a thing from licensed productions of the Flanker *rollseyes*.

Yano what's an even simpler answer? SAC either a) based the J-31 off their rejected J-XX proposal/some other in house design that never made it past models (companies experiment), or B) They simply decided to make a design that isn't based on any of their previous ones. Impossible.

[JSR]

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

PAK-FA will be flying higher and faster than anything out there. i doubt line of sight probable. even use of afterburner has minimilst impact.





There is always TVC to flip around in a moment to show the stealthy face. The more boxy design you make the less stealthy and less range.

[Amiga500]

Re: anticopyists:

So what do you suggest they do?

Hang the engines off the f**king wingtips?

Or how about stick the vertical fins on top of the cockpit?




It has 2 engines, JSF has one. Just including that design change means a completely different structure and available internal volumes.

The wider fuselage back means completely different aerodynamics.


Oh look, it has 2 wings, 2 elevators and 2 vertical fins. What a copy. Handley Page had those back in WW1.

[Hush-kit]

More J-21 analysis here: http://hushkit.wordpress.com/2012/09...ealth-fighter/

[Inst]

J-31 isn't the J-XX, however. It's the F-35 in a Chinese hi-lo combo; it's not even authorized by AVIC; it's a private project paid for by SAC funds as an export product. It's a late product and looks highly derivative; none of the decisions made were remotely original.

Su-27 might have been derivative of the F-14; you don't know, but one is variable sweep and the other is not. You should also remember that the Soviets had their espionage network and weren't aiming at cutting edge design; they were planning to be an N-1 army compared to the US military; 1-step behind cutting edge and greater numbers to compensate.

Eurocanards are not all copies of each other and are highly distinguished by their canard placement and size. Rafale and Gripen are close-coupled, Eurofighter is long-coupled, some of these have good radars, some of these have crap radars and are more A2G optimized.

YF-23 carries design lineage from the F-5 and F-20 Tigershark; both of which used a trapezoidal wing, which you can see is highly emphasized on the YF-23 in comparison to the F-22. There are significant departures from the F-5, though; the F-5 and F-20 has essentially no body lift aspects and are closer to wings attached to a tube, whereas the YF-23 is the exact opposite, which is essentially 3 tubes, one for the cockpit and radome, two for the engines, attached to a wing.

As far as the Flanker production experience goes, the Chinese flanker clones suck. They're like the WS-10; it's domestic and that's great, but the Chnese flankers aren't competitive with the Russian fighters; the J-11B lacks canards like the Su-30 or TVC like the MKI. It's also in part supporting evidence for the J-31 is a F-35 copy argument; CAC has been innovative and has been able to pursue original planform designs with the J-10 and JF-17, but all SAC does these days is "Receive and Duplicate". If they've been involved in "R&D" on the Flankers, why not "Receive and Duplicate" the F-35?

Yano what's an even simpler answer? SAC either a) based the J-31 off their rejected J-XX proposal/some other in house design that never made it past models (companies experiment), or B) They simply decided to make a design that isn't based on any of their previous ones. Impossible.

Show me the rejected J-XX proposal. We can establish a lineage for the J-20 on the J-12 and J-10 designs, but where's the J-XX proposal? And as far as simply deciding to make a design that isn't based on any of their previous models goes, "receive and duplicate"; we haven't seen any significant design capability from SAC for a long time; the J-11B is worse than the Su-30 and is virtually a copy anyways.

[Inst]

Amiga: At least give me some damn variety. Splice a LEVCON onto the F-35 airframe. Try to develop an F-35-class aircraft from the YF-23 direction instead of the F-22 direction; hell, the YF-23 lost to the YF-22 because of a lack of maneuverability and high costs; that's not a problem for an F-35 equivalent!

[latenlazy]

J-31 isn't the J-XX, however. It's the F-35 in a Chinese hi-lo combo; it's not even authorized by AVIC; it's a private project paid for by SAC funds as an export product. It's a late product and looks highly derivative; none of the decisions made were remotely original.

Su-27 might have been derivative of the F-14; you don't know, but one is variable sweep and the other is not. You should also remember that the Soviets had their espionage network and weren't aiming at cutting edge design; they were planning to be an N-1 army compared to the US military; 1-step behind cutting edge and greater numbers to compensate.

Eurocanards are not all copies of each other and are highly distinguished by their canard placement and size. Rafale and Gripen are close-coupled, Eurofighter is long-coupled, some of these have good radars, some of these have crap radars and are more A2G optimized.

YF-23 carries design lineage from the F-5 and F-20 Tigershark; both of which used a trapezoidal wing, which you can see is highly emphasized on the YF-23 in comparison to the F-22. There are significant departures from the F-5, though; the F-5 and F-20 has essentially no body lift aspects and are closer to wings attached to a tube, whereas the YF-23 is the exact opposite, which is essentially 3 tubes, one for the cockpit and radome, two for the engines, attached to a wing.

As far as the Flanker production experience goes, the Chinese flanker clones suck. They're like the WS-10; it's domestic and that's great, but the Chnese flankers aren't competitive with the Russian fighters; the J-11B lacks canards like the Su-30 or TVC like the MKI. It's also in part supporting evidence for the J-31 is a F-35 copy argument; CAC has been innovative and has been able to pursue original planform designs with the J-10 and JF-17, but all SAC does these days is "Receive and Duplicate". If they've been involved in "R&D" on the Flankers, why not "Receive and Duplicate" the F-35?



Show me the rejected J-XX proposal. We can establish a lineage for the J-20 on the J-12 and J-10 designs, but where's the J-XX proposal? And as far as simply deciding to make a design that isn't based on any of their previous models goes, "receive and duplicate"; we haven't seen any significant design capability from SAC for a long time; the J-11B is worse than the Su-30 and is virtually a copy anyways.

I hope you know how silly you sound. Eurocanards, which look a lot more like each other, not sharing as many features as the YF-23 shares with the F-5 and F-20. But I guess you at least concede that Lockmart must've copied the McDonnell Douglas F-15 under your definition of copied.

http://www.hitechweb.genezis.eu/chin..._fighter_2.jpg
http://www.f-16.net/attachments/j_xx_186.jpg
http://media.photobucket.com/image/r...C/jxx3a9vv.jpg

[Inst]

Latenlazy: Your first two pictures have canards and the third has a Mig-29-style LERX. There's no ascertaining whether it was CAC or SAC involved in it, although with the first two, they clearly look like SAC's triplane canard-wing-tail configuration.

[MadRat]

The last one looked like a swing wing of some type.