J-20... The New Generation Fighter II
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Red___Sword
Junior Member
Buddy, can you give an original link to that article?
Everytime when this SDF webpage have a big chunck of quoted Chinese characters, my browser almost stops response as hell. Anyone got the same problem?
Original link, please!
pugachev_diver
Banned Idiot
Now continuing with the translation. From now on, I'll translate a chapter at a time. This post is way too much of a brain drain to finish. Althoug very technical, it is in typical net level grammar and strcuture, so it is hard to make it flow.
Anyways, carry on with the translation.
Chapter Two - Confusion in Planning
Designing an airplane is the hardest thing to do in the branch of engineering, due to the self contradictions in the deamnds themselves. When one demand in certain area rises, then the optimal value in another area will undoubtedly be affected. A jet fighter usually pursues to be an all rounded fighter, seeking balance in all areas of requiremsnts, such as those of speed, agility, and stealthiness.
Just the wing surface itself for an example, big wing area will decrease the stress load, increase agility during subsonic speeds. But at the same time, it will affect the climb rate and wing lift. Delta wings are the best for supersonic flights, but at the same it increases stress on the wings, make it very hard to performance agile manoeuvres. After using those sluggish 2nd generation fighters, like the F4, F5, and F104, those that emphasize on supersonic speeds, the American Air Force could no longer bare it. They believe that when jets are fully loaded, it is very rare that they would go into pure supersonic dog fights. Since the F15, they aggressively adopted the low wing stress design (literally means big wing area, which disperses the load per area unit on the wing, but this creates lots of drag) and high power engines. BUt to those countries lacking high thrust engines, it is impossible for them to do the same. When the F22 flew, it's proved to be even more radical and aggressive in utilizing this design, using highly swept butterfly shaped wings, which maintains supersonic agility while decreases wing stress. It reached perfect balance with those unhumanly powerful F119; without F119, those large butterfly wings would make the plane very sluggish. This design is very simple and effecient, but even so, the high tech materials and especially the challenging demand for a super complexed flight conrol system, created by the insane amount of control surfaces resulted from designing a stealthy layout still remain an uncrossable obstacle for other nations for the last 2 decades.
We had no decent engines, no decent materials, but we did early stage validation researches, and with fast progressing civil industrial development, by the time of building a prototype, these problems were already almost all solved. To design and study a 5th generation stealth fighter, the CHinese researchers and military personnels must decide their main focus:
1. Is it going to be light, medium, or heavy?
Undoubtedly, despite advancements in materials and avoinics to allow the plane sizes to decreases, fighter jets still progress to increase in size. One reason is for bigger combat radius, the other is for more complexed avoincis, even jamming instruments began to be standard built in devices. F-16 and J10s combat radius and agility match those of much heavier counterparts, but their flexibility cannot match those heavy fighters. (I guess he meant the ability to perform multiple type of missions. Since bigger planes can perform more types of missions because they can carry more diversed types of weapons and avoinics due to their sizes.)
The introduction of stealth as a standard for 5th gen jets is a new challenge. Although the Russians proposed the plasma stealth plan, it is still too far from being practical and operational. The internal bays enormity and the S-like intake will definitely cause increase in size. (No idea what he is trying to say here. Maybe he meant the size of J20 is a challenge in achieving stealth.)
China could totally take a low risk approach and design a medium sized jet, with weapon bays similar to those of the silent eagle. But its ability still can't match those of a heavy fighter.
China never had individually developed a heavy fighter on its own, but this time it's an exception. The loom of 96 Strait Crisis still hang over our head. The ability to attack is a must have criteria.
2. what is the body design going to be?
After 96, it was time to examine the countermeasures we have. Chinese researchers thoroughly analysed F22s design, also S37 and Mig 1.42 when they were exposed. But to our own planes, the researchers had no idea what was going to happen as they are hopeless to our military industrial complex.
Adopting a conventional layout similar to the F22 is the most safe approach, but both China and Russia realised, when being behind in material science and engines, it is impossible to rival a f22 with conventional layout design. Prior to 2000, China and Russia cooperated in those technological fields, but did not reach a full agreement on the 5th gen fighter. BUt for sure, prior to publishing of <design for a plane layout with small aspect ratio procucing high lift> by Professor Song of the 611 institute (chengdu), China already did a lot of groundwork on the early stage research for the 5th gen, but a final layout design was still not selected.
In this research paper, Prof Song discussed the result 611 institute came up with in the early 90s when studying for teh possibility of 4th gen. This design's vortex lift is emphasized on the outer edge of the delta, leading edge extension, and pneumatic coupling of the wing; the diamond shaped head was adopted due to its stealthiness and stability when flying in large angle of attack in side angles (no idea how to explain this, I just understand it as being super stable when performing exotic moves during dog fights), but it was not well integrated into the overall design. The vortex in the nose section was still considered to be a harmful factor. The nose of the J-10 today is one fo the more stable layouts designed from early developments, largely followed the knowledges acquired from J-9s wind tunnel testing. The even more radical dual delta wings were dropped due to being too risky to attempt. The gradual swept wing + canard design mentioned in the <small aspect ratio> paper was probably a new revision of the earlier sacked double delta canard design.
Gradual swept is like F-18 and J20, where the trapezius like wing extens gradually and smoothly extend from the nose to the main wing, where as the old double delta card design is like J-10, two set of triangular wings mounted on a pencil.
This research paper was still only a candidate proposal, Shenyang also had its own proposal. In the competition, Shenyang criticised the canard's design flaws, explained how pure single delta wing is beneficial to a plane's balance, agility, and lift. But several problems still exist....
got something to do right now, will start again with this chapter in about 30 minutes....
Anyways, carry on with the translation.
Chapter Two - Confusion in Planning
Designing an airplane is the hardest thing to do in the branch of engineering, due to the self contradictions in the deamnds themselves. When one demand in certain area rises, then the optimal value in another area will undoubtedly be affected. A jet fighter usually pursues to be an all rounded fighter, seeking balance in all areas of requiremsnts, such as those of speed, agility, and stealthiness.
Just the wing surface itself for an example, big wing area will decrease the stress load, increase agility during subsonic speeds. But at the same time, it will affect the climb rate and wing lift. Delta wings are the best for supersonic flights, but at the same it increases stress on the wings, make it very hard to performance agile manoeuvres. After using those sluggish 2nd generation fighters, like the F4, F5, and F104, those that emphasize on supersonic speeds, the American Air Force could no longer bare it. They believe that when jets are fully loaded, it is very rare that they would go into pure supersonic dog fights. Since the F15, they aggressively adopted the low wing stress design (literally means big wing area, which disperses the load per area unit on the wing, but this creates lots of drag) and high power engines. BUt to those countries lacking high thrust engines, it is impossible for them to do the same. When the F22 flew, it's proved to be even more radical and aggressive in utilizing this design, using highly swept butterfly shaped wings, which maintains supersonic agility while decreases wing stress. It reached perfect balance with those unhumanly powerful F119; without F119, those large butterfly wings would make the plane very sluggish. This design is very simple and effecient, but even so, the high tech materials and especially the challenging demand for a super complexed flight conrol system, created by the insane amount of control surfaces resulted from designing a stealthy layout still remain an uncrossable obstacle for other nations for the last 2 decades.
We had no decent engines, no decent materials, but we did early stage validation researches, and with fast progressing civil industrial development, by the time of building a prototype, these problems were already almost all solved. To design and study a 5th generation stealth fighter, the CHinese researchers and military personnels must decide their main focus:
1. Is it going to be light, medium, or heavy?
Undoubtedly, despite advancements in materials and avoinics to allow the plane sizes to decreases, fighter jets still progress to increase in size. One reason is for bigger combat radius, the other is for more complexed avoincis, even jamming instruments began to be standard built in devices. F-16 and J10s combat radius and agility match those of much heavier counterparts, but their flexibility cannot match those heavy fighters. (I guess he meant the ability to perform multiple type of missions. Since bigger planes can perform more types of missions because they can carry more diversed types of weapons and avoinics due to their sizes.)
The introduction of stealth as a standard for 5th gen jets is a new challenge. Although the Russians proposed the plasma stealth plan, it is still too far from being practical and operational. The internal bays enormity and the S-like intake will definitely cause increase in size. (No idea what he is trying to say here. Maybe he meant the size of J20 is a challenge in achieving stealth.)
China could totally take a low risk approach and design a medium sized jet, with weapon bays similar to those of the silent eagle. But its ability still can't match those of a heavy fighter.
China never had individually developed a heavy fighter on its own, but this time it's an exception. The loom of 96 Strait Crisis still hang over our head. The ability to attack is a must have criteria.
2. what is the body design going to be?
After 96, it was time to examine the countermeasures we have. Chinese researchers thoroughly analysed F22s design, also S37 and Mig 1.42 when they were exposed. But to our own planes, the researchers had no idea what was going to happen as they are hopeless to our military industrial complex.
Adopting a conventional layout similar to the F22 is the most safe approach, but both China and Russia realised, when being behind in material science and engines, it is impossible to rival a f22 with conventional layout design. Prior to 2000, China and Russia cooperated in those technological fields, but did not reach a full agreement on the 5th gen fighter. BUt for sure, prior to publishing of <design for a plane layout with small aspect ratio procucing high lift> by Professor Song of the 611 institute (chengdu), China already did a lot of groundwork on the early stage research for the 5th gen, but a final layout design was still not selected.
In this research paper, Prof Song discussed the result 611 institute came up with in the early 90s when studying for teh possibility of 4th gen. This design's vortex lift is emphasized on the outer edge of the delta, leading edge extension, and pneumatic coupling of the wing; the diamond shaped head was adopted due to its stealthiness and stability when flying in large angle of attack in side angles (no idea how to explain this, I just understand it as being super stable when performing exotic moves during dog fights), but it was not well integrated into the overall design. The vortex in the nose section was still considered to be a harmful factor. The nose of the J-10 today is one fo the more stable layouts designed from early developments, largely followed the knowledges acquired from J-9s wind tunnel testing. The even more radical dual delta wings were dropped due to being too risky to attempt. The gradual swept wing + canard design mentioned in the <small aspect ratio> paper was probably a new revision of the earlier sacked double delta canard design.
Gradual swept is like F-18 and J20, where the trapezius like wing extens gradually and smoothly extend from the nose to the main wing, where as the old double delta card design is like J-10, two set of triangular wings mounted on a pencil.
This research paper was still only a candidate proposal, Shenyang also had its own proposal. In the competition, Shenyang criticised the canard's design flaws, explained how pure single delta wing is beneficial to a plane's balance, agility, and lift. But several problems still exist....
got something to do right now, will start again with this chapter in about 30 minutes....
pugachev_diver
Banned Idiot
Shenyang criticised the flaws in conventional canard design. They also presented the benefits of their deisgn, which was a tri-delta design, similar to that of early Su-33. You can think of it as a F22 with canards. THe canards are a delta, the wing is another delta, the last is the large horizontal stabilizer. They explained how its better for balancing, maneouvering, and lift. But it still has some unavoidable flaws; including tri-delta design would increase RCS signatures more than canards and conventional layouts would, it would create drag which add burden to the engines. Therefore 601 institute has a conventional design as a backup. It was this undecisiveness and hesistation that made Shenyang lost the competition for the contract of heavy stealth fighter.
But, Chengdu's proposal was much more challenging than the conventional layout. As a result, they had a cutthroat promise (engineers will lose their jobs if it's not successful). Now the J-20 program finally started striding towards its fruition.
Canard design literally means adding a pair of canards close to the pilots position. Many nations have studied this layout, it was even studied prior to WWII. The Soviets also went into great depth with the Mig-21 but failed. None of the countries were sucessful in the beginning. This layout was not amazing, but not too bad either. Prior to the 80s, the primitive flight control systems were not powerful enough to support the canard designs. Only until 4-axis control became standard, that's when canard designs began to thrive.
Quoting from an expert, up to the 60s, all planes were designed to keep the airflow and supressed air from diccipating; but as the demand for agility and angle of attack increased, the separation was unavoidable. As close-coupling (literally means canards been super close to the main delta wing), Gripen took practical use of vortex lift, it was able to take control of the separation fo air flow, and vortical flows became widely used until today.
Have to run again, I'll keep translating this afternoon.
But, Chengdu's proposal was much more challenging than the conventional layout. As a result, they had a cutthroat promise (engineers will lose their jobs if it's not successful). Now the J-20 program finally started striding towards its fruition.
Canard design literally means adding a pair of canards close to the pilots position. Many nations have studied this layout, it was even studied prior to WWII. The Soviets also went into great depth with the Mig-21 but failed. None of the countries were sucessful in the beginning. This layout was not amazing, but not too bad either. Prior to the 80s, the primitive flight control systems were not powerful enough to support the canard designs. Only until 4-axis control became standard, that's when canard designs began to thrive.
Quoting from an expert, up to the 60s, all planes were designed to keep the airflow and supressed air from diccipating; but as the demand for agility and angle of attack increased, the separation was unavoidable. As close-coupling (literally means canards been super close to the main delta wing), Gripen took practical use of vortex lift, it was able to take control of the separation fo air flow, and vortical flows became widely used until today.
Have to run again, I'll keep translating this afternoon.
pugachev_diver
Banned Idiot
Despite being a hardcore military fan, I still have to admit that I can't understand half of the technical shit that I'm translating. Please feel free to correct me, as I'm already lost in many areas.
I am happy that the article finally showed up here at sinodefence. The article originally started on Zhonghua and had made several rounds on Chinese military forums.
pugachev_diver
Banned Idiot
this is insanely tiring....But I actually learned a lot. normally when you read posts this long, you tend to skip through it quickly. You jump between sentences. But I would have to understand every sentence to the full in order to properly translate it.
It will be mind fucking to read at first as it is very techinical. But later on it's really a piece of cake.
continued.....
Quoting from an expert, "up to the 60s , second gen fighter jets' layout still focus on keeping the adhesive airflow from diccipating, but as demand for agility forces the angle of attack to constantly go up, the diccipation/gap becomes unavoidable.(this is a phenomenon observed in modern high speed jets. Everyone knows that the difference in the speed of air flow over wing surface create lift. But as time goes on, this difference becomes too great that the high pressure zone under the wing breaks off for a little instant. This is dangerous as it could down the plane) But with the introduction of close coupling double delta design's utilization of vortex lift (explained earlier already, this is when the delta wing is mounted super close to the front canard) in the Gripen becoming popular, achieving controllability over airflow diccipation issues, the technique of spreading the diccipation of the edge of the wings became popular and are still used today. A jet's utilizaition of vortex lift is mainly done through vortex lift initiators' (canards, leading edge root extension (LERX)
) front creating a stable vortex. The fast spinning vortex decreases the pressure over the wing surface, the vortex's intensity increases with the increase angle, creating large amount of vortex lift. But its increase is too drastic, adding immense difficulties to a jet's 4-axis control system. There were 3 stages of developments in conquering the vortex effect. The first classic is F15, this early 3rd g en jet didn;t have vortex initiators, it didn;t utilize the vortex lift effect. It's layout is naturally stable. Then comes F16, the first true 3rd gen jet, along with Su27. Both have small sidecurtains as vortex initiators, and both let easy on the natural stablity of the plane and using simulated fly-by-wire systems. The third, is adopting large sideskirts, like those of F18 and FC1, the other is canard style Typhoon, Rafael, Gripen and J10. These jets all use highly unstable configuration, simulated fly-by-wire no longer works, 4-axis fly by wire becomes a standard. Naturally, the more agile a plane is, the more dangerous it is to fly, as it is more natually unstable. In a conventional layout, the surface controlling the pitch is usually at the rear of the vehicle, some even gone extreme to raise level of control, by further extending passing the engine, thinking that as airflow passes a flat plane will not apply further effects on the plane, but canard layouts have its vortex right around its nose, making it much more turbulent. Conventional layout doesn't employ front vortex initiator designs doesn't necessarily reflect that its designers don;t understand the benefits, they do have similar designs like movable sideskirts similar to carnards, it is more becuase of the cause and effect relationship, which the cuase is too great for the relatively low payback. But great turbulence does mean greater potential. A jet with a set of full-motion canards (like those on J20, almost turning a full circle) is better than conventional layout in terms of aerodynamic feature and controllability, including those recently adopted large side skirts. This is why these planes came out later and have good flight characterisitcs. Once people even called full-motion canard layout planes 3.5gen, if looking from an aerodynamic and fly-by-wire point of view, this claim is not groundless, as they are exctremely challenging."
But anything would have two sides to it, canard layouts do bring lots of benefits, but it doesn't mean super maneouverability, it instead brings better vortex lift and natural unstability. To countries without good engines, this is good news. But it also bears many problems, apart from sophisticated fly-by-wire systems, there is another big problem. Canards have two effects, providing controllable lift and control pitch movements. Controllable vortex lift was already mentioned, pitch movement force influence is another effect being applied to the plane, also the hardest problem to solve on canard layout compared to conventional counterparts.
Any plane would have a centre of gravity and a centre of lift foce, if those two overlap in the same area, the plane would be balanced in the air. Although canards can do the same, but different positions of the canards put different level of emphasis on those two. Even just where to put the canards is already a big headache for all design bureaus around the world.
The position of the canards reflect its designers emphais on the plane's inteded characteristics. In fact, if ndermining fuel effeciency, weapon load and other factors, the centre of gravity is usually stable. But the centre of lift changes with speed, orientation of the flight and others, would need a horizontal stabilizer and elevator, or canards to maintain balance, this is balancing effect. By purposely offset the balance, it would cause the plane to pitch up and down. Although canards can perform this more effectively, different positioning of the carnards show emphasis on two different ideals. Having carnards more closer to the front is called distant coupling, because it has the long arm effect, small canards are enough to control the pitch. They are lighter and create less drag. It is more suitable to high speed flights. Its weakness is the far distance between the two deltas are hard to generate vortexed to create lift. Canards closer to the back are called close coupling. close coupling canards are usually very close to the delta wing and are almost merging as one with the main wing. This create much larger vortexes and is suitable for agile maneouvres. But because the "arms" are short, the control on the pitch movement is limited. The surface areas have to be increased to get the same result compared to a distant coupling canard. This adds weight and especially drag. Also when two deltas closely situate to one another, their turbulences intefere with each others'.
To put it simply, this contradiction always bothered engineers around the world. The US did even more research than Europe in the 80s. Lift generating side skirts apeared long time ago. In 1970, NASA had a high speed maneouvre aircraft technology demonstrator. The 17A proposal uses such layout, but limited to the aerodynamics and electronic capability of its time, it was later abandoned. In 1997s May, NASA and Boeing jointly developed the X36 carnard layout demonstrator. This plane used lift generation canard layout, along with stealth and agility as part of its core testing areas. But the Americans believe, doesn't matter if its close or distant coupling, neither is beneficial to the next generation fighter. This is truly sad for the carnard layout, as it is dropped by the biggest and the most powerul air force in the world. The American concluded that "advantages of the canard layout exists only on the enemies". This is pretty much trying to force the idea of "non-stealthiness" onto the canard configuration. But China Aviation Inc. back in early 90s already studied thoroughly on the stealthiness of this layout. In fact the JSF layout and the Gripen proved that canard makes no difference on the stealthiness compared to conventional layouts.
QUoting from expert again, "canard and conventional don;t make much difference in terms of stealth performance, doesn;t matter if its conventional or canard, all their stealtiness are calculated assuming they are in cruising state, and almost completely neglected when maneouvering or only do minimals, but this doesn't influence its figure (I guess he meant the overall RCS value). Canard layout and conventionals' only difference is that canard has an extra surface in the front compared to conventionals. But the front view of the plane wouldn't change. (like a sword, doesn;t matter how long it is, you can only see a small point when its pointed at you). the canard itself can be made to be stealthy. canard and conventional layouts' difference in stealth performance can only be substantial when the RCS is lowered down to 0.001 and it has to be scanned by very powerful radars with specific wavelengths."
The American engineers' original intention was that: canards are too complicated, it takes up too much space internally, especially that it creates too much drag that it kills F22's emphasis on supersonic cruise. When you have unhuman level engine and really good materials and especially highly mature avoinics, why create further troubles for ourself. F22 emphasizes on supersonic speed, utilizing its swept butterfly wings and F119 makes it reach perfect harmony. In the late 90s, the Americans concluded this would dominate the world theatre for 20-30 years.
Doesn't matter if its close coupling or distant coupling, both are detrimental to thenext generation fighter, why so?
To be Continuted.....
It will be mind fucking to read at first as it is very techinical. But later on it's really a piece of cake.
continued.....
Quoting from an expert, "up to the 60s , second gen fighter jets' layout still focus on keeping the adhesive airflow from diccipating, but as demand for agility forces the angle of attack to constantly go up, the diccipation/gap becomes unavoidable.(this is a phenomenon observed in modern high speed jets. Everyone knows that the difference in the speed of air flow over wing surface create lift. But as time goes on, this difference becomes too great that the high pressure zone under the wing breaks off for a little instant. This is dangerous as it could down the plane) But with the introduction of close coupling double delta design's utilization of vortex lift (explained earlier already, this is when the delta wing is mounted super close to the front canard) in the Gripen becoming popular, achieving controllability over airflow diccipation issues, the technique of spreading the diccipation of the edge of the wings became popular and are still used today. A jet's utilizaition of vortex lift is mainly done through vortex lift initiators' (canards, leading edge root extension (LERX)
) front creating a stable vortex. The fast spinning vortex decreases the pressure over the wing surface, the vortex's intensity increases with the increase angle, creating large amount of vortex lift. But its increase is too drastic, adding immense difficulties to a jet's 4-axis control system. There were 3 stages of developments in conquering the vortex effect. The first classic is F15, this early 3rd g en jet didn;t have vortex initiators, it didn;t utilize the vortex lift effect. It's layout is naturally stable. Then comes F16, the first true 3rd gen jet, along with Su27. Both have small sidecurtains as vortex initiators, and both let easy on the natural stablity of the plane and using simulated fly-by-wire systems. The third, is adopting large sideskirts, like those of F18 and FC1, the other is canard style Typhoon, Rafael, Gripen and J10. These jets all use highly unstable configuration, simulated fly-by-wire no longer works, 4-axis fly by wire becomes a standard. Naturally, the more agile a plane is, the more dangerous it is to fly, as it is more natually unstable. In a conventional layout, the surface controlling the pitch is usually at the rear of the vehicle, some even gone extreme to raise level of control, by further extending passing the engine, thinking that as airflow passes a flat plane will not apply further effects on the plane, but canard layouts have its vortex right around its nose, making it much more turbulent. Conventional layout doesn't employ front vortex initiator designs doesn't necessarily reflect that its designers don;t understand the benefits, they do have similar designs like movable sideskirts similar to carnards, it is more becuase of the cause and effect relationship, which the cuase is too great for the relatively low payback. But great turbulence does mean greater potential. A jet with a set of full-motion canards (like those on J20, almost turning a full circle) is better than conventional layout in terms of aerodynamic feature and controllability, including those recently adopted large side skirts. This is why these planes came out later and have good flight characterisitcs. Once people even called full-motion canard layout planes 3.5gen, if looking from an aerodynamic and fly-by-wire point of view, this claim is not groundless, as they are exctremely challenging."
But anything would have two sides to it, canard layouts do bring lots of benefits, but it doesn't mean super maneouverability, it instead brings better vortex lift and natural unstability. To countries without good engines, this is good news. But it also bears many problems, apart from sophisticated fly-by-wire systems, there is another big problem. Canards have two effects, providing controllable lift and control pitch movements. Controllable vortex lift was already mentioned, pitch movement force influence is another effect being applied to the plane, also the hardest problem to solve on canard layout compared to conventional counterparts.
Any plane would have a centre of gravity and a centre of lift foce, if those two overlap in the same area, the plane would be balanced in the air. Although canards can do the same, but different positions of the canards put different level of emphasis on those two. Even just where to put the canards is already a big headache for all design bureaus around the world.
The position of the canards reflect its designers emphais on the plane's inteded characteristics. In fact, if ndermining fuel effeciency, weapon load and other factors, the centre of gravity is usually stable. But the centre of lift changes with speed, orientation of the flight and others, would need a horizontal stabilizer and elevator, or canards to maintain balance, this is balancing effect. By purposely offset the balance, it would cause the plane to pitch up and down. Although canards can perform this more effectively, different positioning of the carnards show emphasis on two different ideals. Having carnards more closer to the front is called distant coupling, because it has the long arm effect, small canards are enough to control the pitch. They are lighter and create less drag. It is more suitable to high speed flights. Its weakness is the far distance between the two deltas are hard to generate vortexed to create lift. Canards closer to the back are called close coupling. close coupling canards are usually very close to the delta wing and are almost merging as one with the main wing. This create much larger vortexes and is suitable for agile maneouvres. But because the "arms" are short, the control on the pitch movement is limited. The surface areas have to be increased to get the same result compared to a distant coupling canard. This adds weight and especially drag. Also when two deltas closely situate to one another, their turbulences intefere with each others'.
To put it simply, this contradiction always bothered engineers around the world. The US did even more research than Europe in the 80s. Lift generating side skirts apeared long time ago. In 1970, NASA had a high speed maneouvre aircraft technology demonstrator. The 17A proposal uses such layout, but limited to the aerodynamics and electronic capability of its time, it was later abandoned. In 1997s May, NASA and Boeing jointly developed the X36 carnard layout demonstrator. This plane used lift generation canard layout, along with stealth and agility as part of its core testing areas. But the Americans believe, doesn't matter if its close or distant coupling, neither is beneficial to the next generation fighter. This is truly sad for the carnard layout, as it is dropped by the biggest and the most powerul air force in the world. The American concluded that "advantages of the canard layout exists only on the enemies". This is pretty much trying to force the idea of "non-stealthiness" onto the canard configuration. But China Aviation Inc. back in early 90s already studied thoroughly on the stealthiness of this layout. In fact the JSF layout and the Gripen proved that canard makes no difference on the stealthiness compared to conventional layouts.
QUoting from expert again, "canard and conventional don;t make much difference in terms of stealth performance, doesn;t matter if its conventional or canard, all their stealtiness are calculated assuming they are in cruising state, and almost completely neglected when maneouvering or only do minimals, but this doesn't influence its figure (I guess he meant the overall RCS value). Canard layout and conventionals' only difference is that canard has an extra surface in the front compared to conventionals. But the front view of the plane wouldn't change. (like a sword, doesn;t matter how long it is, you can only see a small point when its pointed at you). the canard itself can be made to be stealthy. canard and conventional layouts' difference in stealth performance can only be substantial when the RCS is lowered down to 0.001 and it has to be scanned by very powerful radars with specific wavelengths."
The American engineers' original intention was that: canards are too complicated, it takes up too much space internally, especially that it creates too much drag that it kills F22's emphasis on supersonic cruise. When you have unhuman level engine and really good materials and especially highly mature avoinics, why create further troubles for ourself. F22 emphasizes on supersonic speed, utilizing its swept butterfly wings and F119 makes it reach perfect harmony. In the late 90s, the Americans concluded this would dominate the world theatre for 20-30 years.
Doesn't matter if its close coupling or distant coupling, both are detrimental to thenext generation fighter, why so?
To be Continuted.....
Last edited:
pugachev_diver
Banned Idiot
I'll keep going since I'm in a pretty good pace right now. Can't belive how hard this is.... You guys better read the whole thing, or else my effort will drip away in vain.
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