J-20 5th Gen Fighter Thread VI

[Iron Man]

View attachment 48035

I never did get why the canards even have the ability to deflect this much. Surely such extreme deflection could not be used during flight???

Think about what the Sun Zi quote means. You appear weak because you are trying to provoke conflict and get your opponent to fall into a trap. You appear strong because you are vulnerable and wish to deter the opponent. In China's current state, where the USN and USAF pose credible threats, it has to appear strong to avoid conflict and a J-20 doing 24 deg / sec sustained turns deters, while not revealing its full capability.

It is utterly surreal to conclude anything about the J-20's maneuverability based on one's personal opinion of whether the PLAAF is applying Sun Tzu's principles to photo or video ops of the J-20. I mean, seriously, how more comical can this get?

 

[Air Force Brat]

I never did get why the canards even have the ability to deflect this much. Surely such extreme deflection could not be used during flight???


It is utterly surreal to conclude anything about the J-20's maneuverability based on one's personal opinion of whether the PLAAF is applying Sun Tzu's principles to photo or video ops of the J-20. I mean, seriously, how more comical can this get?

You're partly right, the "distant coupled/long throw canards" are the key to Dr. Songs strategy to increase the "pitch rate", since he would not have access to "thrust vectoring engines". So he/they designed the J-20 with those distant coupled canard's in order to increase the "pitch rate" of the aft mounted delta wing J-20. You're right, in a normal flight around the patch, even during heavy maneuvering those canards never approach the limit of their "throw".

The theory and practice is that in a turning fight, at some point as speed and energy are depleted and the limits of thrust and lift are crossed the aircraft will "depart" or stall. As that happens in previous generation aircraft, the aircraft then "departs" from sufficient lift and controlled flight, "pitching the nose down", and ending the fight. Those "long throw" canards allow you to "maintain" that very high alpha and "point your nose" at the bogey and launch weapons as you continue to "turn inside" of him.

Those long throw canard's and under wing "ventral strakes" are the key to the J-20's post stall maneuverability,, while many did not/do not, like those "ventral strakes", they are the key to maintaining longitudinal stability post stall.. they will not go away as long as "super maneuverability", and post stall maneuvering remain a high priority of the J-20 program.

They could conceivably be replaced by "thrust vectoring", note the Su-57 has very small vertical stabilizers, but I rather doubt Chengdu would want to go back and start from scratch on the FCS..




As to your second point, in fact an informed or interested observer can determine a great deal from a picture or video, bdpopeye, Jeff Head, and Deino are able to determine a great deal from a photo or video? that's why the PRC restricts the release of un-authorized photo's or video's, right?

As the previous poster alluded, one thing "fighter wonks" track is degrees of turn per second, for instance if the J-20 completed a 360 degree turn in 15 seconds, we could conclude a 24 degree per second turn "rate", so in theory you can have a very good idea of terminal performance.

 

[Iron Man]

You're partly right, the "distant coupled/long throw canards" are the key to Dr. Songs strategy to increase the "pitch rate", since he would not have access to "thrust vectoring engines". So he/they designed the J-20 with those distant coupled canard's in order to increase the "pitch rate" of the aft mounted delta wing J-20. You're right, in a normal flight around the patch, even during heavy maneuvering those canards never approach the limit of their "throw".

The theory and practice is that in a turning fight, at some point as speed and energy are depleted and the limits of thrust and lift are crossed the aircraft will "depart" or stall. As that happens in previous generation aircraft, the aircraft then "departs" from sufficient lift and controlled flight, "pitching the nose down", and ending the fight. Those "long throw" canards allow you to "maintain" that very high alpha and "point your nose" at the bogey and launch weapons as you continue to "turn inside" of him.

Those long throw canard's and under wing "ventral strakes" are the key to the J-20's post stall maneuverability,, while many did not/do not, like those "ventral strakes", they are the key to maintaining longitudinal stability post stall.. they will not go away as long as "super maneuverability", and post stall maneuvering remain a high priority of the J-20 program.

They could conceivably be replaced by "thrust vectoring", note the Su-57 has very small vertical stabilizers, but I rather doubt Chengdu would want to go back and start from scratch on the FCS..




As to your second point, in fact an informed or interested observer can determine a great deal from a picture or video, bdpopeye, Jeff Head, and Deino are able to determine a great deal from a photo or video? that's why the PRC restricts the release of un-authorized photo's or video's, right?

As the previous poster alluded, one thing "fighter wonks" track is degrees of turn per second, for instance if the J-20 completed a 360 degree turn in 15 seconds, we could conclude a 24 degree per second turn "rate", so in theory you can have a very good idea of terminal performance.

Thanks for the info. As for the photos and videos, my point was somewhat different. If certain (extreme) performance features of the J-20 have already been revealed to the public, that is all well and good and does give us some information about its capabilities, but one cannot determine capabilities based simply on what has NOT been revealed, whether you believe the alleged motivation is to "hide strength" or "hide weakness". That is a silly game of speculation based on lack of information and goes nowhere fast.

 

[Air Force Brat]

Thanks for the info. As for the photos and videos, my point was somewhat different. If certain (extreme) performance features of the J-20 have already been revealed to the public, that is all well and good and does give us some information about its capabilities, but one cannot determine capabilities based simply on what has NOT been revealed, whether you believe the alleged motivation is to "hide strength" or "hide weakness". That is a silly game of speculation based on lack of information and goes nowhere fast.

That's right, China tends hold its cards close to the vest, until they are ready to "put their cards on the table"! you make a very good point, guesstimating on what you don't know, or what you would like to think you? usually leaves you "out in the weeds"

 

[latenlazy]

You're partly right, the "distant coupled/long throw canards" are the key to Dr. Songs strategy to increase the "pitch rate", since he would not have access to "thrust vectoring engines". So he/they designed the J-20 with those distant coupled canard's in order to increase the "pitch rate" of the aft mounted delta wing J-20. You're right, in a normal flight around the patch, even during heavy maneuvering those canards never approach the limit of their "throw".

The theory and practice is that in a turning fight, at some point as speed and energy are depleted and the limits of thrust and lift are crossed the aircraft will "depart" or stall. As that happens in previous generation aircraft, the aircraft then "departs" from sufficient lift and controlled flight, "pitching the nose down", and ending the fight. Those "long throw" canards allow you to "maintain" that very high alpha and "point your nose" at the bogey and launch weapons as you continue to "turn inside" of him.

Those long throw canard's and under wing "ventral strakes" are the key to the J-20's post stall maneuverability,, while many did not/do not, like those "ventral strakes", they are the key to maintaining longitudinal stability post stall.. they will not go away as long as "super maneuverability", and post stall maneuvering remain a high priority of the J-20 program.

They could conceivably be replaced by "thrust vectoring", note the Su-57 has very small vertical stabilizers, but I rather doubt Chengdu would want to go back and start from scratch on the FCS..

If CAC is testing a TVC equipped WS-10 on the J-20 like certain illustrations suggest then they’re already working on a revised FCS. I don’t think the ventral strakes are likely to go away either, but there’s always an off chance we’ll see that or other aerodynamic revisions if TVC integration into the FCS is drastic.

As to your second point, in fact an informed or interested observer can determine a great deal from a picture or video, bdpopeye, Jeff Head, and Deino are able to determine a great deal from a photo or video? that's why the PRC restricts the release of un-authorized photo's or video's, right?

As the previous poster alluded, one thing "fighter wonks" track is degrees of turn per second, for instance if the J-20 completed a 360 degree turn in 15 seconds, we could conclude a 24 degree per second turn "rate", so in theory you can have a very good idea of terminal performance.

It’s very hard to track kinematic performance in a video without a stationary frame. Even then we can’t even take a stab at elevation and speed parameters without knowing distance to the camera, which we will need to know which part of the flight envelope the plane is manuevering in. Videos can tell us a lot, but there are very clear limits to what it can inform, and that includes kinematics. Even if they could give us a clear picture of kinematic performance though most videos of fighters manuevering are taken on the slow and low end of their flight envelope. It makes no sense to derive anything about their performance at that end of the envelope when that’s not the flight regime they’re supposed to conduct most of their operations in.

 

[taxiya]

Nope. Here's the thing, what's China's objective military condition? China is a nuclear power, true, but it has a small arsenal that is potentially vulnerable to BMD. When it comes to the PLAN + PLAAF vs the USN / USAF, it's a no-brainer; the USAF and USN outsizes it, and if 10, or even 6 CSGs were to pop on the coast, with BMD defenses, while the USN / USAF would take losses, eventually there would be enough bombs falling on Chinese cities to throw it back to the 80s or even earlier.

Think about what the Sun Zi quote means. You appear weak because you are trying to provoke conflict and get your opponent to fall into a trap. You appear strong because you are vulnerable and wish to deter the opponent. In China's current state, where the USN and USAF pose credible threats, it has to appear strong to avoid conflict and a J-20 doing 24 deg / sec sustained turns deters, while not revealing its full capability.

Don't mechanically put Sun Zi's words in reality. Sun Zi has never asked his student to do exactly word for word. He has also said "故其战胜不复，而应形于无穷", it means no victorious act can be repeated exactly, it always have to be adopted to the ground. Otherwise, you know the infamous armchair general Zhao Kuo who not only got himself killed but also 400,000 soldiers with him.

A good example is Marshal Liu Bocheng's 129 division did two ambushes at the same place to the Japanese troops under the same commander. Marshal Liu's act was apparently against the "right" way in the text book. But it is the real right way.

Let's play a mind game. You argue for "one must pretend strong when weak". Since I also read Sun Zi's book, I know that you are pretending strong while being weak, so I call your bluff, what will you do?

Now turn us around. I am weak and I act weak (not following your suggestion), and since you follow the texts of "Sun Zi", will you interpret my "act weak" as "I am actually strong"? You must because you follow the texts, right? So my "act weak" must be the true spirit of Sun Zi's teaching even I act against "his" texts???

 

[Deino]

Guys ... back to the J-20 or just stopp.

 

[Deino]

 

[DaTang cavalry]

View attachment 48052

nice picture!

 

[Deino]

nice picture!

Even better one !

J-20A 2021 + WS-10B