J20 Stealth Fighter

asianobserve

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The long rumored Twin Seat J20 seems close to breaking cover. The characteristically blurry pics trending online seem legit, but...

View attachment 116167
View attachment 116168

Another proof that J-20 is not a true 5th gen fighter since all 5th gen fighters are single seaters. The computational power and level of integration in J-20 is 4th gen like F-14.
 

J20!

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Another proof that J-20 is not a true 5th gen fighter since all 5th gen fighters are single seaters. The computational power and level of integration in J-20 is 4th gen like F-14.
🤣☝🏼Hold up. Didn't the Indian Airforce's stillborn FGFA programme detail a requirement for a twin seat SU57?🤔

I'd go through the reasons why having a low signature passive sensor and networking node in a high EMI battle space would be invaluable or how an additional targeting decision maker on board a stealth platform would suit the PLAAFs current operations model or the benefits of a dedicated WSSO managing UCAV swarms from a low signature platform rather than a vulnerable, high radar signature, J16 or AEW platform...

but we all know you're just trolling so why bother?
 
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asianobserve

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🤣☝🏼Hold up. Didn't the Indian Airforce's stillborn FGFA programme detail a requirement for a twin seat SU57?🤔

I'd go through the reasons why having a low signature passive sensor and networking node in a high EMI battle space would be invaluable or how an additional targeting decision maker on board a stealth platform would suit the PLAAFs current operations model or the benefits of a dedicated WSSO managing UCAV swarms from a low signature platform rather than a vulnerable, high radar signature, J16 or AEW platform...

but we all know you're just trolling so why bother?

So the WSO will remote control wingman drones...? Tells you a lot about the level of autonomy of these Chinese drones...
 

J20!

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So the WSO will remote control wingman drones...? Tells you a lot about the level of autonomy of these Chinese drones...
I believe I used the word "manage". Do you even know what rules of engagement are? Even piloted platforms seek clearance from a battlespace manager - usually aboard AWACS - before pursuing a target. Mostly to avoid friendly fire in a complicated and congested battlespace.

You honestly believe any competent Airforce commander would allow UCAVs to autonomously engage targets in airspace where he has dozens or hundreds of friendly assets?

The largest operators of armed and reconnaissance UAVs, ie US armed forces, (and CIA) have humans in the kill chain for making final target prosecution decisions. Or do you doubt their AI capability too?

You're kind of tripping over your own arguments in a rush to troll China(as usual).
 

MiG-29SMT

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J-20 has a delta wing with leading root extensions and a trailing edge with a sweept back angle, however it can be considered a trapezoidal wing.


Let us see

Delta wings • Advantages: • Delta wings have a long root chord and therefore can have a thick main spar while retaining a low thickness-‐to-‐chord ratio. • They also have larger wing area than trapezoidal wings with the same aspect ratio. This means low wing loading even during maneuvers. • There is a lot internal volume for fuel and landing gear. • At low speed conditions they can produce a lot of additional lift when placed at high angle of attack, thanks to the leading edge vortices. • Delta wing aircraft do not require a horizontal tail. • Disadvantages: • Higher viscous drag due to the large wing area. • High induced drag at subsonic conditions due to low aspect ratio. • Bad deep stall. • Pitch control is achieved by deflecting upwards the trailing edge control surfaces in order to produce a nose up moment. This reduces the total amount of lift generated by the wing. • This problem can be overcome by incorporating a horizontal tail or lifting canards.


• The pitch control and bad deep stall disadvantages of Delta wings led to several variations: • Compound Delta or Ogive Delta: the inboard sweep is generally higher so as to create even stronger leading edge vortices and delay stall to even higher angles. • Exception: Saab 37 Viggen. • The Ogive Delta also reduces supersonic drag. • Horizontal tail: Provides additionally stability in pitch and therefore the wing can produce more lift. Tail elevator provides pitch control • Canards: They are usually all-‐moveable and provide additional pitch control. The aircraft is usually statically unstable. • Note also that flaps are difficult to use with a tailless Delta configuration. • Delta wings are generally cropped. The pointy wingtip is difficult to manufacture and structurally weak. Furthermore, cropped Delta wings delay vortex bursting. • The centre of lift lies aft on a Delta wing. This means that the horizontal tail can only be effective if it lies even further aft. Usually the tail is highly swept and can be placed on a highly swept fin.

Trapezoidal wings • In trapezoidal wings, the leading edge sweeps back but the trailing edge sweeps forward. • Some Delta wings also feature a slight sweep forward angle at the trailing edge. • Advantages • Better performance than Delta wings at transonic speeds and during transition to and from supersonic conditions. • They do not require upwards deflection of the trailing edge control surfaces for pitch control and therefore do not lose lift. • Their centre of lift lies further forward and therefore the tail must not lie too far back on the fuselage. • They are preferred for stealth applications. • Flaps can be easily used. • Disadvantages: • High wing loading. • They stall at much lower angles of attack than Delta wings. • This problem is overcome using Leading Edge (Root) eXtensions (LEX or LERX) and/or canards


• Trapezoidal wings are mostly used by the US. • They are nearly always combined with a conventional horizontal tail and single or twin fin. • They are nearly always combined with LEX. • Some trapezoidal wings look like highly cropped Delta wings (F-‐16 for example). • Modern trapezoidal wings have very highly swept leading edges, approaching the sweep of Delta wings.




source http://www.ltas-cm3.ulg.ac.be/AERO0023-1/ConceptionAeroFighter.pdf

The YF-23 has trapezoidal wings as they stall at much lower angles of attack than Delta wings, this problem is overcome using Leading Edge (Root) eXtensions (LEX or LERX) and/or canards, thus YF-23 has very long and sharp LERX. The Trapezoidal wings have the centre of lift lies further forward and therefore the tail must not lie too far back on the fuselage. They are preferred for stealth applications, all these features are seen on YF-23.

1635406645113.png

Compared to YF-23, J-20 has a delta wing with a trailing edge swept back, we can say it has a trapezoidal wing that is closer to a delta wing. J-20 has the following features:
J-20 has canards, they are all-‐moveable and provide additional pitch control. The aircraft is very likely statically unstable. Delta wings are generally cropped. The pointy wingtip is difficult to manufacture and structurally weak. Furthermore, cropped Delta wings delay vortex bursting. J-20 has cropped wings. The centre of lift lies aft on a Delta wing compared to a trapezoidal wing

1635406682454.png

The Blackbirds not only incorporated cutting-edge materials, but also some novel design concepts (Fig. 14). The Lockheed team developed a monocoque structure for the fuselage and nacelles, and a multispar/multirib wing structure with chordwise corrugations for stiffness and to prevent warping at high temperatures. This resulted in a failsafe redundant structure. The presence of fuselage side-fairings, or chines, generated nearly 20 percent of the aircraft’s total lift. Acting as fixed canards they produced a favorable effect on trim drag and minimized the aft shift of the aerodynamic center of pressure as the aircraft’s speed increased from subsonic to supersonic. Additionally, vortices from the chines improved directional stability of the aircraft as angle of attack increased. The chines also provided a convenient housing for wires and plumbing on either side of the cylindrical center-body fuel tanks.



J-20 has very small wing LEX to be able to generate as much lift as the LEX on YF-23 or SR-71, in fact relying more on the canards to do that function

1635406842902.jpeg

Tricycle gear airplanes are built in the 'Delta' configuration, with the airplane's center of gravity slightly forward of the main gear.


We can see J-20 has its main landing gear far forward from the main wing, forcing the canards and forward fuselage to generate proportionally more lift than other modern delta canard fighters and compromising more its reduced static stability more.

For a conventional, statically stable supersonic fighter aircraft, the centre of gravity is located in front of the neutral point of the aircraft during subsonic cruise. This requires a negative balancing lift force on the horizontal stabilizer. During supersonic cruise, the neutral point of the aircraft moves further aft which increases the longitudinal stability of the aircraft. This results in an increase in trim drag, due to the larger balancing negative lift force required on the horizontal stabilizer. For an aircraft which possesses relaxed static stability, the centre of gravity is located behind the neutral point during subsonic cruise. This results in a negative Stability Margin (SM) and represents an unstable subsonic flight condition. During the supersonic cruise phase the neutral point of the aircraft moves aft to a point at which it is located just behind the centre of gravity, requiring only a small negative balancing lift force on the horizontal stabilizer. This significantly increases the supersonic manoeuvrability and decreases the supersonic trim drag.


Two-surface aircraft are defined as an aircraft with two lifting surfaces. The possible two-surface aircraft configurations are the conventional and canard aircraft. The canard has a stabilizing surface, called a canard, in front of the wing instead of a horizontal stabilizer behind the wing. There can be design requirements why an aircraft engineer might opt for a canard configuration over a conventional configuration. One advantage of a canard aircraft is, that the aircraft can be trimmed, where both lifting surfaces provide a lift force in the positive direction. In contrast to a conventional aircraft, where the horizontal stabilizer will provide a relatively small down force in order to balance the nose down pitching moment of the wing-fuselage combination.



High levels of instability enable excellent maneuverability properties for fighter aircraft. For instance the X-36 tailless demonstrator 10 or the Grumman X-29 forward-swept wing experimental aircraft (see figure 1(a)), are both designed with negative static stability margins (35%l for the X-29 11 ); as a result any perturbation from an initial longitudinal equilibrium makes the aircraft dynamically depart. If this motion is adequately controlled, superior longitudinal maneuverability is obtained. .



Tail surfaces, for example, add weight and aerodynamic drag, and having the aircraft CG forward of the wing's center of lift as required for positive natural, i.e., unaugmented, stability in pitch, requires a download on the tail for equilibrium.

one of the advantages of Reduced Static Stability (RSS) in pitch that was exploited in the basic design of the F-16 Falcon jet fighter. By integrating so-called RSS into the basic aircraft design, equilibrium of pitching increments was achieved with the horizontal tail generating lift rather than download, so that the lift that the wing must produce to carry the weight of the aircraft is reduced. This means a smaller wing with less structural weight and drag can be incorporated into the overall design.

 

Alien_cat26

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Why twin seater j-20?

Trainer?
Bomber?
Not enough AI/sensor fusion thus resulting huge single pilot workload?
Air Force Squadron Command Platform.
The J-20 stealth fighter most of the time it will leave the early warning aircraft to perform tasks, so it can assume a temporary command platform and mobilize air tactics.
 

Maharaj skandgupta

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I believe I used the word "manage". Do you even know what rules of engagement are? Even piloted platforms seek clearance from a battlespace manager - usually aboard AWACS - before pursuing a target. Mostly to avoid friendly fire in a complicated and congested battlespace.

You honestly believe any competent Airforce commander would allow UCAVs to autonomously engage targets in airspace where he has dozens or hundreds of friendly assets?

The largest operators of armed and reconnaissance UAVs, ie US armed forces, (and CIA) have humans in the kill chain for making final target prosecution decisions. Or do you doubt their AI capability too?

You're kind of tripping over your own arguments in a rush to troll China(as usual).
Those edges , those bloody edges of this black beauty ufff...
 

Maharaj skandgupta

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Asian observe is from Philippines , please don't drag Indian airforce here.
I believe I used the word "manage". Do you even know what rules of engagement are? Even piloted platforms seek clearance from a battlespace manager - usually aboard AWACS - before pursuing a target. Mostly to avoid friendly fire in a complicated and congested battlespace.

You honestly believe any competent Airforce commander would allow UCAVs to autonomously engage targets in airspace where he has dozens or hundreds of friendly assets?

The largest operators of armed and reconnaissance UAVs, ie US armed forces, (and CIA) have humans in the kill chain for making final target prosecution decisions. Or do you doubt their AI capability too?

You're kind of tripping over your own arguments in a rush to troll China(as usual).
 

shiphone

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lol...as promised

the maiden flight of twin-seater seems to lag behind the NG carrier-borne fighter, but it won't be very far away.
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at this stage ,in the PLAAF plan ,no other fighter porject would have higher priority than J-20. for the air force J20 is the king and everything. forget that 'FC-31' project' for export .

if you are expecting some new PLAAF toys in fighter catologue , I would recommend some new member of J-20 'family'... it will be the next star...lol

 

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