J20 Stealth Fighter

[MiG-29SMT]

finally.. the maiden flight of J-20(X) with WS-15 TVC took place today...

---------
the TVC nozzle on the J10B flying testbed.

that is no evidence but a rumour, the picture is needed

 

[MiG-29SMT]

alledgedly new engine

 

[asianobserve]

J-20 has stealth treatment, compromised by aerodynamics, but in general terms it will be shot down, the Su-30MS and Su-35s have already been flown to track them, F-15EX shows F-35 is not that good, because it is too expensive and too unreliable, same is J-20

Such a flawed logic. F-35 is not good because it's too expensive? What you're implying is actually yes F-35 is better but it's more expensive. In other words the F-35 is not for poor countries.

But even on cost the F-35A at current fly away price of less than $80M is already cheaper than a most low volume 4th gen or so called 4.5th gen fighters. How much is the current fly away cost of Rafale, $100M?

 

[MiG-29SMT]

Such a flawed logic. F-35 is not good because it's too expensive? What you're implying is actually yes F-35 is better but it's more expensive. In other words the F-35 is not for poor countries.

But even on cost the F-35A at current fly away price of less than $80M is already cheaper than a most low volume 4th gen or so called 4.5th gen fighters. How much is the current fly away cost of Rafale, $100M?

The Rafale is expensive but in aerodynamics it is probably the best dogfighter right now.

to fly you need lot of lift and thrust

F-35 has not a lot of lift nor thrust, it relies in remain hidden long enough to allow hit and run tactics.

F-22 in order to have good agility relies in engines 50% more powerful than Al-31 add TVC nozzles they will alow the agility of a Rafale with external stores.

The Rafale can resist F-22 without TVC nozzles, why?

well turn rates are related to lift, Rafale has around 300kg over squared meter, and thrust vectoring only improves turn rates 9%, so if you have a turn rate of 22 deg/s with thrust vectoring it will go 24 deg/s.

If a MiG-29 has a sustained turn rate of 22 deg/s at sea level armed it will go higher without weapons perhaps 25 deg/s but it will not have weapons to fight.


For F-22 to have better turn rates than a clean MiG-29 needs a bigger wing and much powerful engines basically 100% more powerful and almost twice of wing area.

F-35 is under powered its small wing does not generate lots of lift.

J-20 like F-22 is heavy, been heavy means it needs very powerful engines and stronger structure.

stealth imposes too much constraigns to aerodynamics believe me Rafale is a really good aircraft perhaps not as stealthy but for sure it is very agile.

 

[lixun]

that is no evidence but a rumour, the picture is needed

Although there is no picture, judging from all sources of news, J20 used ws15 for its first flight.
1. It marks that WS15 has officially entered the stage of aircraft and engine matching and debugging.
2. At the same time, the environmental and accessory tests of WS15 were carried out. The durability test of WS15 passed the preliminary test.
3. This is the first time China has skipped the flight deck test after the high-altitude deck test.
4. WS15 uses a two-dimensional vector nozzle, similar to F22, instead of the three-dimensional vector nozzle used by J10Btvc

 

[lixun]

Such a flawed logic. F-35 is not good because it's too expensive? What you're implying is actually yes F-35 is better but it's more expensive. In other words the F-35 is not for poor countries.

But even on cost the F-35A at current fly away price of less than $80M is already cheaper than a most low volume 4th gen or so called 4.5th gen fighters. How much is the current fly away cost of Rafale, $100M?

First of all, the value of the F35 lies in its informationized combat capability, as well as the concept of operational cloud and mosaic warfare developed by this capability. If you want to rely on a few F35s to seize air superiority, it is almost impossible.

 

[Maharaj samudragupt]

First of all, the value of the F35 lies in its informationized combat capability, as well as the concept of operational cloud and mosaic warfare developed by this capability. If you want to rely on a few F35s to seize air superiority, it is almost impossible.

Welcome back comrade.

 

[lixun]

The J-20 has unprecedentedly adopted the extremely complex design of lifting body + DSI inlet + full-moving canard + large side strip + tailless delta + full-moving vertical tail. The overall shape is like a sharp dart. Let's analyze the characteristics of the aerodynamic layout of the J-20 one by one.

The lift body is an unconventional aerodynamic layout. There is no ordinary wing, but a wing body fusion body is used to generate lift in order to obtain a higher lift-to-drag ratio at low speeds. The concept of the lift body was originally discovered by accident when NASA was studying ballistic missile reentry technology, and was later applied to the design of returnable spacecraft. At first glance, a pure lift body looks like a rock, but this rock can generate lift by itself and can fly.

X-24A verification machine, the purest lift body design, no main wing
In traditional aircraft design, the fuselage is used to carry loads and the wings are used to generate lift. They are two independent parts.

The third-generation aircraft introduced the concept of wing-body fusion in the design, and the smooth transition between the fuselage and the wing through the curve, not only reduces aerodynamic drag, but also increases the volume of the fuselage. Both the F-14 and Su-27 are typical integrated lift body designs. The rear fuselage is a part of the wing, which is wide and flat, with a wing-like longitudinal section that can generate partial lift. The engine adopts the form of nacelles under the wings, arranged at large intervals, and the tunnel formed between the two engines can restrict the airflow, increase the pressure on the lower surface, and improve the lift. When the F-14 wing sweep angle is 20°, the fuselage lift accounts for 40% of the total lift; when the wing sweep angle is 68°, the fuselage lift accounts for 60% of the total lift, which is amazing in efficiency. But the third-generation aircraft is not a real lift body, but a part of the lift body design is adopted in the rear fuselage, because of the times, stealth and supersonic maneuverability are not considered at all.

In order to realize the unification of stealth, supersonic cruise and super maneuverability, the fourth-generation aircraft mostly adopted supersonic lift body design. The entire fuselage starts with a diamond-shaped nose, the upper and lower surfaces adopt smooth continuous surfaces with large curvature, and the fuselage and wings are integrated. The cambered lower side of the diamond-shaped nose can generate lift and pre-compress the airflow to the air inlet. The longitudinal section of the fuselage is similar to the airfoil, and the configuration is very clean, which is not only conducive to the diffraction of radar waves, but also makes the entire fuselage an ideal lift body, generating additional lift.

Thanks to the flat binary vector nozzle at the tail, the F-22 lift body design is the most perfect.

J-20 Secondly, the catch is that the tail engine cannot be narrowed because of the traditional three-way nozzle, which will lead to higher induced drag. Just yesterday, China first flew the WS15 with a binary vector nozzle, and the lift body is more perfect.
.

Su57 inherited the aerodynamic layout of Su-27, the design is the most conservative, the bulging front fuselage and hanging engine nacelle have destroyed the continuity of the surface of the fuselage, far behindthe trend. .

 

[MiG-29SMT]

The J-20 has unprecedentedly adopted the extremely complex design of lifting body + DSI inlet + full-moving canard + large side strip + tailless delta + full-moving vertical tail. The overall shape is like a sharp dart. Let's analyze the characteristics of the aerodynamic layout of the J-20 one by one.

The lift body is an unconventional aerodynamic layout. There is no ordinary wing, but a wing body fusion body is used to generate lift in order to obtain a higher lift-to-drag ratio at low speeds. The concept of the lift body was originally discovered by accident when NASA was studying ballistic missile reentry technology, and was later applied to the design of returnable spacecraft. At first glance, a pure lift body looks like a rock, but this rock can generate lift by itself and can fly.
View attachment 96494
X-24A verification machine, the purest lift body design, no main wing
In traditional aircraft design, the fuselage is used to carry loads and the wings are used to generate lift. They are two independent parts.

J-20 has no lifting body per say.

That is Chinese forumlore

J-20 has fuselage chamber and chines, X-24 was a glider got it, it was designed to be a glider free falling like the Space shuttle


see it was a glider, it took off with a B-52 and basically it was a re-entry vehiicle

The third-generation aircraft introduced the concept of wing-body fusion in the design, and the smooth transition between the fuselage and the wing through the curve, not only reduces aerodynamic drag, but also increases the volume of the fuselage. Both the F-14 and Su-27 are typical integrated lift body designs. The rear fuselage is a part of the wing, which is wide and flat, with a wing-like longitudinal section that can generate partial lift. The engine adopts the form of nacelles under the wings, arranged at large intervals, and the tunnel formed between the two engines can restrict the airflow, increase the pressure on the lower surface, and improve the lift. When the F-14 wing sweep angle is 20°, the fuselage lift accounts for 40% of the total lift; when the wing sweep angle is 68°, the fuselage lift accounts for 60% of the total lift, which is amazing in efficiency. But the third-generation aircraft is not a real lift body, but a part of the lift body design is adopted in the rear fuselage, because of the times, stealth and supersonic maneuverability are not considered at all.

View attachment 96496
In order to realize the unification of stealth, supersonic cruise and super maneuverability, the fourth-generation aircraft mostly adopted supersonic lift body design. The entire fuselage starts with a diamond-shaped nose, the upper and lower surfaces adopt smooth continuous surfaces with large curvature, and the fuselage and wings are integrated. The cambered lower side of the diamond-shaped nose can generate lift and pre-compress the airflow to the air inlet. The longitudinal section of the fuselage is similar to the airfoil, and the configuration is very clean, which is not only conducive to the diffraction of radar waves, but also makes the entire fuselage an ideal lift body, generating additional lift.

Thanks to the flat binary vector nozzle at the tail, the F-22 lift body design is the most perfect.

J-20 Secondly, the catch is that the tail engine cannot be narrowed because of the traditional three-way nozzle, which will lead to higher induced drag. Just yesterday, China first flew the WS15 with a binary vector nozzle, and the lift body is more perfect.
.
Su57 inherited the aerodynamic layout of Su-27, the design is the most conservative, the bulging front fuselage and hanging engine nacelle have destroyed the continuity of the surface of the fuselage, far behindthe trend. .

J-20 was based like any stealth aircraft on the basic hopeless diamond

however stealth contradicts aerodynamics

ideally you need a sears haack body

that is the best aerodynamic shape of low drag thus it is used in bullets and ICBMs

F-117 used facets and B-2 uses a wing that sends strong signals to the sides when flying towards the target in a straight direct attack

By the way drop the 3rd generation we do not used in the west and you will not teach us

basic corpuscular wave behavior

acting like a particle the wave will reflect like a ball

but waves do have a problems they also behave like waves got it?

the creeping waves needs a flat surface canted and diamond shaped cross section, but the Sears Haack body needs a round circular cross section got it?


So the blended body is the best solution and what fighter used the most?

J-20 andf F-35 conventional fuselages are less optimised in aerodynamics than Su-57 and YF-23 shows the best stealth-aerodynamics blending off any stealth fighter and so is

 

[lixun]

The DSI inlet is a revolutionary innovation in aerodynamics, and it cannot be overstated on this point. However, the introduction of the DSI inlet on the Internet is often a picture, so we can't feel its subtleties.
First of all, we have to answer a question, why do supersonic aircraft need air inlets?

The gas turbine engine used in supersonic aircraft needs to inhale air to work. However, the engine can only inhale subsonic gas, and direct inhalation of supersonic airflow will cause the engine blades to tremble and damage. Therefore, we need a supersonic inlet (the blue part in the figure below) to decelerate the supersonic airflow to subsonic speed.

The intake duct not only needs to decelerate, but also needs to provide uniform intake for the engine. Because there is friction between the aircraft fuselage and the air, the surface of the aircraft fuselage is often stained with a layer of air with a slower flow rate, called the boundary layer.

In order to prevent the boundary layer from entering the air inlet, there is a gap between the air inlet and the nose of the aircraft in the figure below. This gap is called the boundary layer divider. It is responsible for separating the low-velocity airflow of the boundary layer from the supersonic airflow.

What happens if the boundary layer accidentally enters the inlet? It will cause uneven pressure distribution in the intake duct, with serious consequences. In rare cases, the engine blades are cyclically stressed and tremble, causing metal fatigue and reducing engine life.In severe cases, it will cause extremely dangerous engine compressor stall and surge, damaging the engine
Supersonic fighters work in a wide range of speed and altitude, as well as maneuvering conditions. The higher the altitude, the thinner the air, and the faster the aircraft flies, the greater the air flow through the air intake. However, the engine is very picky, and the intake air flow and pressure must be maintained within a certain range for the engine to work efficiently. To match the working environment of the engine, the intake duct usually requires complex movable parts to adjust the airflow. For example, the adjustable shock cone air inlet of SR-71

When the supersonic airflow encounters a sharp object or a small deflection, an oblique shock wave will be generated, and the oblique shock wave will be reflected inside the intake duct.

The supersonic airflow decelerates to a slower supersonic airflow every time it passes through an oblique shock wave. After 10 oblique shock waves, the supersonic airflow gradually decelerates until it decelerates to a critical point, at which time a positive shock wave will appear.

After the forward shock wave, the supersonic airflow (red area in the figure below) will be decelerated to subsonic airflow (blue area in the figure below), and the airflow at this time can be sucked in by the engine. The deceleration method that passes through many oblique shock waves and one normal shock wave is an efficient deceleration method. The more oblique shock waves passed, the more efficient the deceleration process (the higher the total pressure recovery coefficient).

In the picture below, you can see the dual-adjustable air inlet of the Concorde supersonic passenger plane. The airflow deceleration is still through many oblique shock waves and a normal shock wave. (The gap between the upper surface of the air inlet and the lower surface of the wing is a side-layer partition)

The above air intake has a very complicated mechanical structure. Although it is efficient (the engine hardly loses thrust), it is heavy and expensive. Without these complicated mechanical structures, the engine can only maintain high efficiency at a single speed. For example, the F-16 Pito-style inlet, which is usually used by fighters that focus on subsonic maneuverability. (There is a surface layer separation between the air inlet and the nose)

For the Pito-type inlet, the supersonic airflow will form a positive shock wave in the inlet, and it will instantly decelerate to subsonic airflow. The deceleration method after a forward shock wave is inefficient and will

cause the thrust of the engine to lose 13-15%

 

[MiG-29SMT]

The DSI inlet is a revolutionary innovation in aerodynamics, and it cannot be overstated on this point. However, the introduction of the DSI inlet on the Internet is often a picture, so we can't feel its subtleties.
First of all, we have to answer a question, why do supersonic aircraft need air inlets?

The gas turbine engine used in supersonic aircraft needs to inhale air to work. However, the engine can only inhale subsonic gas, and direct inhalation of supersonic airflow will cause the engine blades to tremble and damage. Therefore, we need a supersonic inlet (the blue part in the figure below) to decelerate the supersonic airflow to subsonic speed.
View attachment 96500
The intake duct not only needs to decelerate, but also needs to provide uniform intake for the engine. Because there is friction between the aircraft fuselage and the air, the surface of the aircraft fuselage is often stained with a layer of air with a slower flow rate, called the boundary layer.
View attachment 96501
In order to prevent the boundary layer from entering the air inlet, there is a gap between the air inlet and the nose of the aircraft in the figure below. This gap is called the boundary layer divider. It is responsible for separating the low-velocity airflow of the boundary layer from the supersonic airflow.
View attachment 96503
What happens if the boundary layer accidentally enters the inlet? It will cause uneven pressure distribution in the intake duct, with serious consequences. In rare cases, the engine blades are cyclically stressed and tremble, causing metal fatigue and reducing engine life.In severe cases, it will cause extremely dangerous engine compressor stall and surge, damaging the engine
Supersonic fighters work in a wide range of speed and altitude, as well as maneuvering conditions. The higher the altitude, the thinner the air, and the faster the aircraft flies, the greater the air flow through the air intake. However, the engine is very picky, and the intake air flow and pressure must be maintained within a certain range for the engine to work efficiently. To match the working environment of the engine, the intake duct usually requires complex movable parts to adjust the airflow. For example, the adjustable shock cone air inlet of SR-71View attachment 96507
When the supersonic airflow encounters a sharp object or a small deflection, an oblique shock wave will be generated, and the oblique shock wave will be reflected inside the intake duct.View attachment 96508
The supersonic airflow decelerates to a slower supersonic airflow every time it passes through an oblique shock wave. After 10 oblique shock waves, the supersonic airflow gradually decelerates until it decelerates to a critical point, at which time a positive shock wave will appear.
View attachment 96510
After the forward shock wave, the supersonic airflow (red area in the figure below) will be decelerated to subsonic airflow (blue area in the figure below), and the airflow at this time can be sucked in by the engine. The deceleration method that passes through many oblique shock waves and one normal shock wave is an efficient deceleration method. The more oblique shock waves passed, the more efficient the deceleration process (the higher the total pressure recovery coefficient).
View attachment 96512
In the picture below, you can see the dual-adjustable air inlet of the Concorde supersonic passenger plane. The airflow deceleration is still through many oblique shock waves and a normal shock wave. (The gap between the upper surface of the air inlet and the lower surface of the wing is a side-layer partition)View attachment 96516
The above air intake has a very complicated mechanical structure. Although it is efficient (the engine hardly loses thrust), it is heavy and expensive. Without these complicated mechanical structures, the engine can only maintain high efficiency at a single speed. For example, the F-16 Pito-style inlet, which is usually used by fighters that focus on subsonic maneuverability. (There is a surface layer separation between the air inlet and the nose)

View attachment 96518
For the Pito-type inlet, the supersonic airflow will form a positive shock wave in the inlet, and it will instantly decelerate to subsonic airflow. The deceleration method after a forward shock wave is inefficient and will View attachment 96519cause the thrust of the engine to lose 13-15%

DSI intake is limited to Mach 1.6 at best

and by the way they are old F-11 used the first concepts, the only advantages is optimised to cheaper construction, and cheaper stealth but no optimisation beyond Mach 1.7 after that once it goes to Mach 2 the engine efficiency by 1% in pressure recovery loss will lose 3-5% engine thrust, so your J-20 is going to damage the engines and use more fuel

Supercrusader had a DSI intake of course modern computer can speed up development and integration of the DSI design so drop it it was an american invention and it is old

so yes while Su-57 has a conventional boundary layer diverter its ramps allow Mach 3 performance, while DSI intakes are limited to Mach 1.6 and F-35 and JF-17 are limited to that speed and so are J-20 and J-31 despite our chinese friends say it is hypersonic

 

[ketaki]

Welcome back comrade.

because he is paid for it ... part of his "JOB" at CCP internet propaganda division
otherwise why do you think so many bat eaters are active on DFI?

 

[lixun]

After so much preparation, it's time for the DSI inlet to play. The full name of the DSI inlet is a supersonic inlet without a surface layer, also called a Bump inlet.
First, we use the "3D photo restoration technology" to model the F-35, and get the F-35's nose model

The oblate cone shape of the first half is what we want to observe

The oblate cone shape of the first half is what we want to observe

The oblate cone shape of the first half is what we want to observe

Numerical simulation results show that the oblate cone has a high pressure area, which pushes the boundary layer to the low pressure area at both ends.

The cone of the shock cone inlet of the French Mirage 2000 fighter is also a bulge. Why can't it push the boundary layer to both sides?

The head of the cone will form a uniform high pressure area with a lower pressure than the former, and the airflow will flow evenly through the cone, which will not have the effect of pushing away the surface layer.

Let us return to the bulge of the DSI inlet. There will be air inlet lips on both sides of the bulge, which are responsible for separating the surface layer that is pushed away. (The following schematic diagram is not based on F-35 as a model, but the principle is similar)

The bulge is a continuous curved surface that causes the supersonic fluid to produce a continuous deflection here, thereby generating a continuous oblique shock wave. We can regard this continuous oblique shock wave as countless oblique shock waves, so it is very efficient to decelerate. It can be seen from the formation of the wind tunnel that a triangular continuous oblique shock wave is formed in front of the bulge, and a normal shock wave in front of the inlet lip.

The continuous curved surface at the bulge in the figure below produces a continuous oblique shock wave. The continuous oblique shock wave forms a triangular area, and finally falls into a normal shock wave. The continuous oblique shock wave and a forward shock wave enable the intake port to achieve efficient air intake.

The difficulty in designing the DSI inlet is that because there is no boundary layer, the disturbance of the airflow by the airframe will affect the air inlet, and the bulge of the air inlet needs to be integrally designed with the airframe. The air intake bulge is a three-dimensional complex surface, and the shock wave system cannot be analyzed by formulas. We need to do computationally intensive numerical simulation and optimization of the fuselage and air intake. In an era when computing power is scarce and expensive, it is not feasible to use DSI inlets. For traditional air inlets with side-layer partitions, the fuselage and air inlets can be designed separately and then assembled together. In addition, the inlets are all 2-dimensional or symmetrical in the center, which facilitates the calculation of the shock wave system with formulas without relying on computer computing power. The advantage of the DSI inlet is that it eliminates the boundary layer partitions and complex moving parts, reduces weight and production costs, while maintaining efficient air intake. It is said that the F-35's air inlet bulge is a whole piece of composite material curved surface glued to the fuselage with resin. The elimination of the boundary layer divider also improves the stealth performance. Radar waves of a specific frequency will resonate in the boundary layer divider of a specific width to generate strong echoes. The disadvantage of the DSI inlet is that the size of the inlet is not adjustable and cannot adapt to a large speed range.

 

[MiG-29SMT]

After so much preparation, it's time for the DSI inlet to play. The full name of the DSI inlet is a supersonic inlet without a surface layer, also called a Bump inlet.
First, we use the "3D photo restoration technology" to model the F-35, and get the F-35's nose model View attachment 96544
The oblate cone shape of the first half is what we want to observe

The oblate cone shape of the first half is what we want to observe

The difficulty in designing the DSI inlet is that because there is no boundary layer, the disturbance of the airflow by the airframe will affect the air inlet, and the bulge of the air inlet needs to be integrally designed with the airframe. The air intake bulge is a three-dimensional complex surface, and the shock wave system cannot be analyzed by formulas. We need to do computationally intensive numerical simulation and optimization of the fuselage and air intake. In an era when computing power is scarce and expensive, it is not feasible to use DSI inlets. For traditional air inlets with side-layer partitions, the fuselage and air inlets can be designed separately and then assembled together. In addition, the inlets are all 2-dimensional or symmetrical in the center, which facilitates the calculation of the shock wave system with formulas without relying on computer computing power. The advantage of the DSI inlet is that it eliminates the boundary layer partitions and complex moving parts, reduces weight and production costs, while maintaining efficient air intake. It is said that the F-35's air inlet bulge is a whole piece of composite material curved surface glued to the fuselage with resin. The elimination of the boundary layer divider also improves the stealth performance. Radar waves of a specific frequency will resonate in the boundary layer divider of a specific width to generate strong echoes. The disadvantage of the DSI inlet is that the size of the inlet is not adjustable and cannot adapt to a large speed range.

Mirage 2000 has a moving intake half cone, .

What happens at Mach 2 with a DSI intake? simple since the shock wave moves and it is fixed more boundary layer air will enter the intake duck.

On Mirage 2000 the half cone at low speeds does not need to be set as a boundary layer diverter because it is in a position deep in the intake as speed increases the intake moves the half cone forward, at low speeds the intakes uses the splitter to take away the boundary layer,

Mirage 2000 or Mirage 4000 will achieve Mach 2.3 with engines of relatively low thrust engine.

JF-17 can not achieve more than Mach 1.7.

JF-17 also has bleeding holes which shows a shallow bump to reduce drag needs bleeding system and on J-20 a huge bumps increase cross section

So it is pure blabla bla

DSI intakes do ingest boundary layer air, once the aircraft speed goes to the Max design number of the intake which is Mach 1.6, bellow Mach 1.6 and Mach 1 do work well, as well as a F-18 or Tejas pitot intake, but at Mach 2, they yield to variable geometry intakes.

By the way for a creeping wave the rounded bump does help, so not everytrhing is as white and black, it simplicity is its main advantage

 

[MiG-29SMT]

After so much preparation, it's time for the DSI inlet to play. The full name of the DSI inlet is a supersonic inlet without a surface layer, also called a Bump inlet.
First, we use the "3D photo restoration technology" to model the F-35, and get the F-35's nose model View attachment 96544
The oblate cone shape of the first half is what we want to observe

The oblate cone shape of the first half is what we want to observe

View attachment 96549
The oblate cone shape of the first half is what we want to observe
View attachment 96550
Numerical simulation results show that the oblate cone has a high pressure area, which pushes the boundary layer to the low pressure area at both ends.
View attachment 96551
The cone of the shock cone inlet of the French Mirage 2000 fighter is also a bulge. Why can't it push the boundary layer to both sides?
View attachment 96552
The head of the cone will form a uniform high pressure area with a lower pressure than the former, and the airflow will flow evenly through the cone, which will not have the effect of pushing away the surface layer.
View attachment 96553
Let us return to the bulge of the DSI inlet. There will be air inlet lips on both sides of the bulge, which are responsible for separating the surface layer that is pushed away. (The following schematic diagram is not based on F-35 as a model, but the principle is similar)View attachment 96556
The bulge is a continuous curved surface that causes the supersonic fluid to produce a continuous deflection here, thereby generating a continuous oblique shock wave. We can regard this continuous oblique shock wave as countless oblique shock waves, so it is very efficient to decelerate. It can be seen from the formation of the wind tunnel that a triangular continuous oblique shock wave is formed in front of the bulge, and a normal shock wave in front of the inlet lip.
View attachment 96557
The continuous curved surface at the bulge in the figure below produces a continuous oblique shock wave. The continuous oblique shock wave forms a triangular area, and finally falls into a normal shock wave. The continuous oblique shock wave and a forward shock wave enable the intake port to achieve efficient air intake.
View attachment 96558
The difficulty in designing the DSI inlet is that because there is no boundary layer, the disturbance of the airflow by the airframe will affect the air inlet, and the bulge of the air inlet needs to be integrally designed with the airframe. The air intake bulge is a three-dimensional complex surface, and the shock wave system cannot be analyzed by formulas. We need to do computationally intensive numerical simulation and optimization of the fuselage and air intake. In an era when computing power is scarce and expensive, it is not feasible to use DSI inlets. For traditional air inlets with side-layer partitions, the fuselage and air inlets can be designed separately and then assembled together. In addition, the inlets are all 2-dimensional or symmetrical in the center, which facilitates the calculation of the shock wave system with formulas without relying on computer computing power. The advantage of the DSI inlet is that it eliminates the boundary layer partitions and complex moving parts, reduces weight and production costs, while maintaining efficient air intake. It is said that the F-35's air inlet bulge is a whole piece of composite material curved surface glued to the fuselage with resin. The elimination of the boundary layer divider also improves the stealth performance. Radar waves of a specific frequency will resonate in the boundary layer divider of a specific width to generate strong echoes. The disadvantage of the DSI inlet is that the size of the inlet is not adjustable and cannot adapt to a large speed range.

Extensive experiments were conducted on a body-integrated diverterless supersonic inlet (DSI). Diverterless supersonic inlets are designed and developed in order to provide both supersonic flow compression and boundary-layer diversion by using a three-dimensional bump in combination with a suitable cowl lip. The present experiments were performed at three different freestream Mach numbers of M∞=0.75, 1.65 (the design Mach number), and 1.85, as well as at 0 deg angles of attack and angles of sideslip

https://www.researchgate.net/publication/333460859_Effects_of_Mach_Number_on_the_Performance_of_a_Diverterless_Supersonic_Inlet

Find what does mean intake design number, once you do that, you will see DSI on J-20 or F-35 have a design number bellow Mach 2, thus for speeds beyond Mach 2 you need a diverter

 

[MiG-29SMT]

 

[MiG-29SMT]

 

[johnq]

The J-20 facade created via a Chinese Communist Party (CCP) funded propaganda campaign is part of CCP psy ops in order to win a war without fighting by intimidating the enemy. However, those who understand how CCP military propaganda works, and how the CCP military is actually technologically backwards by 2 decades compared to modern militaries, can see through this facade created by shiny photoshopped images of shiny toys that don't actually work very well. The back-end of the J-20 radar is copied from 2 decades old, severely downgraded Russian radar technology, hence the J-20 radar cannot compete with modern radar or jamming technology: It may be pretty to look at, but it is backwards by 2 decades. Similarly, the RCS reduction techniques on the J-20 don't work so well due to Chinese technological limitations, which is why IAF and Taiwanese air forces have been able to track it on radar even in x band. There are severe design flaws such as canards and gaps between canards and body which show up as radar resonance hotspots and light up the J-20 even in the x band from the front. It is also a fact that the CCP military has not figured out a way to hide the J-20 radar/radome from being tracked by enemy radar even in x band. This is why the J-20 is visible to enemy radar in x band even from the front; we already know that the J-20 is visible to all bands of radar from the sides and the back due to design deficiencies (canards, nozzles, etc.) The optical/infrared detection system is also severely deficient in terms of ranges, as it's copied from 1990's Russian technology, and also highly unreliable (breaks down a lot). The engines of the J-20 are severely underpowered and have very short lifespans and require overhauls every 80 hours, hence highly unreliable to use in times of actual war. The weapons, such as the air to air missiles, use outdated seeker and backend technology from the 1990s, and can be jammed easily by modern ECM. The J-20 may be pretty to look at in air shows, but is highly deficient in terms of any warfighting capabilities.

 

[MiG-29SMT]

The J-20 facade created via a Chinese Communist Party (CCP) funded propaganda campaign is part of CCP psy ops in order to win a war without fighting by intimidating the enemy. However, those who understand how CCP military propaganda works, and how the CCP military is actually technologically backwards by 2 decades compared to modern militaries, can see through this facade created by shiny photoshopped images of shiny toys that don't actually work very well. The back-end of the J-20 radar is copied from 2 decades old, severely downgraded Russian radar technology, hence the J-20 radar cannot compete with modern radar or jamming technology: It may be pretty to look at, but it is backwards by 2 decades. Similarly, the RCS reduction techniques on the J-20 don't work so well due to Chinese technological limitations, which is why IAF and Taiwanese air forces have been able to track it on radar even in x band. There are severe design flaws such as canards and gaps between canards and body which show up as radar resonance hotspots and light up the J-20 even in the x band from the front. It is also a fact that the CCP military has not figured out a way to hide the J-20 radar/radome from being tracked by enemy radar even in x band. This is why the J-20 is visible to enemy radar in x band even from the front; we already know that the J-20 is visible to all bands of radar from the sides and the back due to design deficiencies (canards, nozzles, etc.) The optical/infrared detection system is also severely deficient in terms of ranges, as it's copied from 1990's Russian technology, and also highly unreliable (breaks down a lot). The engines of the J-20 are severely underpowered and have very short lifespans and require overhauls every 80 hours, hence highly unreliable to use in times of actual war. The weapons, such as the air to air missiles, use outdated seeker and backend technology from the 1990s, and can be jammed easily by modern ECM. The J-20 may be pretty to look at in air shows, but is highly deficient in terms of any warfighting capabilities.

I will be honest, while i do not deny what you wrote might be true but I find it more of a claim than a proof and stealth is only reduced range of detection, how efficient is J-20 can only proven at war, in air combat, not on internet speculation, of course modern AWACS do detect stealth aircraft, but that includes all of them.

 

[MiG-29SMT]