I don't think TVC reduces heat sig. The F-22 has reduced sig because it use flattened rectangular exhausts which depress the IR sig some what at the cost of reduced thrust.
J-20... The New Generation Fighter III
- Thread starter siegecrossbow
- Start date
- Status
I don't think TVC reduces heat sig. The F-22 has reduced sig because it use flattened rectangular exhausts which depress the IR sig some what at the cost of reduced thrust.
MiG-29
Banned Idiot
Squeezing the exhaust through a flat, narrow nozzle produces a mixed plume with a large surface area, which cools quickly. Airframe radiation — whether caused by solar or friction heating — can be reduced with the use of infrared suppressing paints and coating
---------- Post added at 08:48 PM ---------- Previous post was at 08:39 PM ----------
Thurst vectoring nozzles reduce drag that in turn reduce turbulance, if the J-20 applies that it will reduce another signature often overlooked, contrails, contrail detection is another way of detecting Stealth fighters, by using TVC nozzles J-20 will reduce drag and turbulance.
See
Turbulence Reduction
The turbulence of a plane is caused by the movement of the craft disrupting the air around it. The shape of any stealth plane is made so that is EXTREMELY aerodynamic, having the least amount of air resistance. This minimizes the turbulence, and the fuel costs, since the plane is not creating so much drag. The less turbulence, the less likely it is that the enemy's sensitive laser detection equipment will pick up on the plane.
On F-22 and T-50 even contrails have influenced the horizontal stabilizers position see
Air" (moisture) Contrails
"Air" Contrails are the most commonly seen type of contrail. These come from the moisture in the air being disturbed by a wing. When these contrails are created, the pressure of air surrounding the wing is disturbed and unbalanced, causing the moisture to form trails. The F-22 has been able to decrease the likelihood of these contrails because of the horizontal stabilizers located on the aft part of the aircraft. These stabilizers help evenly distribute the lift of the aircraft so that contrails are avoidable
On J-20 the lower drag long coupled canards generate less drag, therefore reduce detection too
However i would not accept the claim of Song`s paper that J-20 has been the first fighter with canards, fuselage lifting body and LERXs. F-22 does have lifting body fuselage traits thanks to wing-fuselage blending, this feature is also seeing on J-20, however Rafale has the same features.
что F-22A вобрал в себя наиболее прогрессивные черты истребителей четвертого поколения. Во-первых, это интегральная аэродинамическая компоновка - плавное сопряжение крыла и фюзеляжа
Last edited:
AeroEngineer
Junior Member
Correct !!
Flat nozzle reduce IR but reduce thrust.
Concentric nozzle will NOT reduce IR but will NOT reduce thrust neither.
You can only choose one, not both !
---------- Post added at 07:45 PM ---------- Previous post was at 07:14 PM ----------
Japanese aerospace industry is superior to Russia's aerospace industry.
Happy??
Correct !!
Flat nozzle reduce IR but reduce thrust.
Concentric nozzle will NOT reduce IR but will NOT reduce thrust neither.
You can only choose one, not both !
---------- Post added at 07:45 PM ---------- Previous post was at 07:14 PM ----------
Japanese aerospace industry is superior to Russia's aerospace industry.
Happy??
We're not happy, we are ecstatic, welcome aboard aero engineer, I assume your not Dr. Song? If you are, hum us a tune, in any regard all joking aside, we are very happy to have you on Sino Defense, and most especially the J-20 thread. I have had a difficult time wrapping my mind around the J-20, and the translation of Dr. Songs paper by siege, no-name, and several other fellows has refreshed my memory. This bird is quite a handfull with all the tweaks and twists. If you look back through this thread their are some outstanding pictures and videos of the J-20.
Sorry Aero, I didn't realize you have been on here over a year, I looked at your join date later, sorry, but You are quite right about the nozzles.
Last edited:
Oh, My Goodness, What A J-20!
Why Should China Bu SU-35?
Found On Internet:
J20出现后一反以往战机的不同，整个机身几乎看不到铆钉，有的人说是因为外面的隐身涂层覆盖了，所以看不到铆钉，其实这是错误的。F22也是用铆钉的，仔细近看就能看出来。为什么F22的铆钉不可以用涂层完全覆盖到看不见呢?这是因为F22的蒙皮是靠铆钉一块一块的铆上去的，铆钉不能覆盖是为了维修方便，万一蒙皮脱落可以迅速拆下铆钉再换一块，而且可以凭肉眼判断机身蒙皮是否有裂缝。
那么J20为什么看不到铆钉呢?其实这和加工工艺有关，由于技术进步，J20的机身采用的的一大块钛铝合金锭整体式铸造，再通过专用压力机挤压，增加密度，(这个机器前两年研制成功，曾经媒体有报道，这台飞机机身压力机就是专为J20研制的)，最后再采用数控机床挖空，这也是一台**型，高精度的数控机床，把整个钛铝合金铸件(直径可能达到3米以上)挖空成飞机机身段的形状，这样飞机就不需要再覆盖蒙皮，机身的框架和蒙皮都是那一块钛铝合金锭加工而成，所以J20根本看不到铆钉。这样的工艺能大幅度的增加飞机强度，而且加工的精确度也提高很多，这是飞机机身加工工艺的一次革命性进步。以往飞机是一步步搭建起来的，先搭建钛铝合金框架，框架间打孔并用螺栓拧紧，然后再用铆钉铆上蒙皮。这些工艺完全是靠手工，精度难以控制，而且如果哪个螺栓没有铆紧或者老化严重的就可能导致整个飞机解体，轻的也会导致蒙皮开裂，所以飞机都要做静力破坏性试验以检验飞机是否达到设计强度。而J20因为采用新工艺加工，整个机身是一体的，达到最佳强度，以后空中做高机动动作导致机身解体的情况将不再出现。
J20在机身加工好后只需要在机身表面贴上隐身贴片，大家注意下面的图，J20的隐身贴片是一块块粘贴上去的，有点象潜艇的吸音橡胶块。如果以后哪块隐身贴片脱落了只需再贴一块新的就OK，这样飞机的维护工作就很轻松。
J20的这个整体式加工技术目前是世界上第一次在飞机上应用，F35都还是靠铆钉铆上的，俄罗斯的T50那就更不用说了，完全是20年前的工艺，根本和J20没有可比性。所以说一架飞机的先进不能光看表面，J20为了战略需要(携带大量燃油增加航程和大型反舰导弹)而设计成超长机身，这样一个机身如果用以往的老工艺加工那么我们凭肉眼看就觉得其机身比例不对，机身太长，机身中段是应力的薄弱处，这里最容易折断，但是采用新工艺后这个缺点就完全消除。所以J20刚问世时国外的飞机设计专家都觉得不可理解，但是一旦了解其加工工艺后对疑问就会豁然开朗。
揭秘：歼20隐身战机360度全方向反射雷达波系
首先我们来看一张示意图：见下图1
这张示意图所反映的就是飞机在水平360度范围内反射雷达波系的情况（普通机载雷达波段，厘米波段），而这正是针对隐身飞机的“全方向”，在正常情况下对于飞机的隐身仅考虑水平360度范围内反射雷达波系的情况。从图中我们可以看出，非隐身飞机全向反射雷达波系都比较强烈，在25dBsm左右，而隐身飞机在全方向仅在几个极小的角度范围内有强烈的反射雷达波系，其他绝大多数角度范围反射波强度均在-10dBsm以下（RCS单位dBsm到m^2的转换公式：σdBsm＝10lgσ，-10dBsm大约为0.1m^2）。这张图也反映了隐身飞机隐身的方法，即把受到的雷达波集中反射到少数的几个极小的角度范围内，让敌人在绝大部分角度看不见你，而在少数角度有一瞬间强烈“反光”，使雷达无法有效探测和锁定。
所以我们看到隐身飞机的俯视图轮廓追求互相平行的边缘，这样散射就会变成沿着截面的向空中背景的绕射，然后将这些锐角截面设计成平行的，则散射和绕射方向趋于相同，则战机会向特定方向反射你的雷达信号，这样你的雷达可以捕捉到战机信号，但由于是特定方向反射，则抓住它的信号只有一瞬，角度一变RCS又急剧降低，则你的雷达屏幕上显示的是偶尔出现一个闪烁无法锁定的信号，北约演习中F-15曾经反映过F-22在目视距离被雷达探测的信号仍然是忽明忽暗无法抓取就是这个原因。
Auto Translation:
J20 appears a reversal of past fighters of different whole body almost see no rivets, and some people outside the stealth coating covering, so do not see the rivets, in fact, this is wrong. The F22 is also the use of rivets, a closer look at the past can be seen. F22 rivets Why not coating completely covered to not see it? This is because the F22 skin rely on the rivet a piece of riveting up the rivets can not cover for easy maintenance, in case of skin shedding can quickly remove the rivets back to one, and can determine whether the fuselage skin cracks with the naked eye. J20 Why look less than a rivet? In fact, this process, due to technological advances the body of the J20 used a large piece of titanium aluminum monolithic ingot casting, extrusion through a dedicated press to increase the density, ( two years before the successful development of this machine, once the media has been reported, this aircraft fuselage press is developed specifically for J20) and finally adopted the hollowing out of the CNC machine tools, and this is a ** type, high-precision CNC machine tools. titanium aluminum castings (diameter could reach more than 3 meters) hollowed out into the shape of the aircraft fuselage section, so that aircraft do not need to cover the processing of the framework of the skin, body and skin are that a titanium aluminum alloy ingots into the J20 simply do not see the rivets. This process can be a substantial increase in aircraft strength, and accuracy of processing also increased a lot, this is a revolutionary step forward in the process of aircraft fuselage. Aircraft in the past is a step by step to build up, the first structures of titanium aluminum alloy frame, perforated between the framework and tighten the bolts, then the rivets riveting the skin. These processes completely by hand, the precision is difficult to control, and which bolt riveting tight or aging may lead to the disintegration of the entire aircraft, light can lead to skin cracking, so planes have to do static destructive testing to verify aircraft to meet the design strength. J20 because of the introduction of new processing technology, the entire body is one, to achieve the best strength, after the air to do maneuver led to the disintegration of the fuselage will no longer appear. J20 in the fuselage surface in fuselage processing only paste the stealth patch, we note the following diagram, the J20 stealth patch pieces pasted a bit like a submarine sound-absorbing rubber. If you later piece of stealth patch off just paste a new on OK, the maintenance of such aircraft is very easy. J20 of the overall processing technology is currently the world's first application in the aircraft, F35, or are relying on the rivets riveting, not to mention the Russian T50, 20 years ago technology, fundamental and J20 did not comparable sex. Said an aircraft's advanced not just look at the surface, J20 designed for strategic need (to carry large amounts of fuel to increase the range and large anti-ship missiles) into a long body, such a body if the old process of the previous processing that we are The naked eye can not think the proportion of its body does not, the body too long, the body the middle of the weaknesses of the stress, the most easily broken, but this shortcoming after the introduction of new technology completely eliminated. J20 had just come out of foreign aircraft design experts feel that incomprehensible, but once you understand the process, doubt it will become clear. Secret: F-20 stealth fighter 360-degree omni-directional reflector radar Department First we look at a diagram: see figure 1 this is reflected in the schematic diagram of the aircraft in the level of 360 degrees within the Department of reflection radar (Airborne radar band, cm band), which is the stealth aircraft "direction" stealth aircraft under normal circumstances, only consider the level of 360 degrees within the Department of reflection radar. From the figure, we can see, the non-stealth aircraft omnidirectional reflector radar system are relatively strong 25dBsm about stealth aircraft in all directions in a very small angle range only a strong reflection of radar waves Department, other most of the range of angles of the reflected wave strength below-10dBsm (the RCS unit dBsm to the conversion formula of m ^ 2: σdBsm = 10lgσ-10dBsm about 0.1m ^ 2). This chart also reflects the stealth aircraft stealth, by the radar to concentrate reflection to a handful of very small angular range, so that the enemy can not see you in the vast majority point of view, the moment strongly in the minority point of view "reflective", the radar can not effectively detect and lock. So we see the top view of the outline of the stealth aircraft to pursue each other parallel to the edge, so that scattering becomes along the cross section of diffraction in the air background, and an acute angle cross section designed to parallel, scattering and diffraction direction tends to the same war opportunity to reflect the radar signal in a particular direction, so that your radar can be captured fighters signal is a specific direction of reflection, to seize the only moment of its signal angle of a RCS drastically reduced, then you radar screen occasionally flashes a signal that can not be locked, and military exercises of NATO F-15 had the F-22 in the visual range radar signal is still flickering unable to crawl This is the reason . J-20, to borrow Russian friends paralay, publicly shared on the network chart analysis: see figure 2 from the point of view this map, the J-20 to 10 waves of the Department of belly is not clear, all-moving vertical tail parallel situation is not clear, and clear may be increased to 12 wave, 10 wave relative to the increase in F-22 to eight wave wave-based wing in front of two edge.
Why Should China Bu SU-35?
Found On Internet:
J20出现后一反以往战机的不同，整个机身几乎看不到铆钉，有的人说是因为外面的隐身涂层覆盖了，所以看不到铆钉，其实这是错误的。F22也是用铆钉的，仔细近看就能看出来。为什么F22的铆钉不可以用涂层完全覆盖到看不见呢?这是因为F22的蒙皮是靠铆钉一块一块的铆上去的，铆钉不能覆盖是为了维修方便，万一蒙皮脱落可以迅速拆下铆钉再换一块，而且可以凭肉眼判断机身蒙皮是否有裂缝。
那么J20为什么看不到铆钉呢?其实这和加工工艺有关，由于技术进步，J20的机身采用的的一大块钛铝合金锭整体式铸造，再通过专用压力机挤压，增加密度，(这个机器前两年研制成功，曾经媒体有报道，这台飞机机身压力机就是专为J20研制的)，最后再采用数控机床挖空，这也是一台**型，高精度的数控机床，把整个钛铝合金铸件(直径可能达到3米以上)挖空成飞机机身段的形状，这样飞机就不需要再覆盖蒙皮，机身的框架和蒙皮都是那一块钛铝合金锭加工而成，所以J20根本看不到铆钉。这样的工艺能大幅度的增加飞机强度，而且加工的精确度也提高很多，这是飞机机身加工工艺的一次革命性进步。以往飞机是一步步搭建起来的，先搭建钛铝合金框架，框架间打孔并用螺栓拧紧，然后再用铆钉铆上蒙皮。这些工艺完全是靠手工，精度难以控制，而且如果哪个螺栓没有铆紧或者老化严重的就可能导致整个飞机解体，轻的也会导致蒙皮开裂，所以飞机都要做静力破坏性试验以检验飞机是否达到设计强度。而J20因为采用新工艺加工，整个机身是一体的，达到最佳强度，以后空中做高机动动作导致机身解体的情况将不再出现。
J20在机身加工好后只需要在机身表面贴上隐身贴片，大家注意下面的图，J20的隐身贴片是一块块粘贴上去的，有点象潜艇的吸音橡胶块。如果以后哪块隐身贴片脱落了只需再贴一块新的就OK，这样飞机的维护工作就很轻松。
J20的这个整体式加工技术目前是世界上第一次在飞机上应用，F35都还是靠铆钉铆上的，俄罗斯的T50那就更不用说了，完全是20年前的工艺，根本和J20没有可比性。所以说一架飞机的先进不能光看表面，J20为了战略需要(携带大量燃油增加航程和大型反舰导弹)而设计成超长机身，这样一个机身如果用以往的老工艺加工那么我们凭肉眼看就觉得其机身比例不对，机身太长，机身中段是应力的薄弱处，这里最容易折断，但是采用新工艺后这个缺点就完全消除。所以J20刚问世时国外的飞机设计专家都觉得不可理解，但是一旦了解其加工工艺后对疑问就会豁然开朗。
揭秘：歼20隐身战机360度全方向反射雷达波系
首先我们来看一张示意图：见下图1
这张示意图所反映的就是飞机在水平360度范围内反射雷达波系的情况（普通机载雷达波段，厘米波段），而这正是针对隐身飞机的“全方向”，在正常情况下对于飞机的隐身仅考虑水平360度范围内反射雷达波系的情况。从图中我们可以看出，非隐身飞机全向反射雷达波系都比较强烈，在25dBsm左右，而隐身飞机在全方向仅在几个极小的角度范围内有强烈的反射雷达波系，其他绝大多数角度范围反射波强度均在-10dBsm以下（RCS单位dBsm到m^2的转换公式：σdBsm＝10lgσ，-10dBsm大约为0.1m^2）。这张图也反映了隐身飞机隐身的方法，即把受到的雷达波集中反射到少数的几个极小的角度范围内，让敌人在绝大部分角度看不见你，而在少数角度有一瞬间强烈“反光”，使雷达无法有效探测和锁定。
所以我们看到隐身飞机的俯视图轮廓追求互相平行的边缘，这样散射就会变成沿着截面的向空中背景的绕射，然后将这些锐角截面设计成平行的，则散射和绕射方向趋于相同，则战机会向特定方向反射你的雷达信号，这样你的雷达可以捕捉到战机信号，但由于是特定方向反射，则抓住它的信号只有一瞬，角度一变RCS又急剧降低，则你的雷达屏幕上显示的是偶尔出现一个闪烁无法锁定的信号，北约演习中F-15曾经反映过F-22在目视距离被雷达探测的信号仍然是忽明忽暗无法抓取就是这个原因。
Auto Translation:
J20 appears a reversal of past fighters of different whole body almost see no rivets, and some people outside the stealth coating covering, so do not see the rivets, in fact, this is wrong. The F22 is also the use of rivets, a closer look at the past can be seen. F22 rivets Why not coating completely covered to not see it? This is because the F22 skin rely on the rivet a piece of riveting up the rivets can not cover for easy maintenance, in case of skin shedding can quickly remove the rivets back to one, and can determine whether the fuselage skin cracks with the naked eye. J20 Why look less than a rivet? In fact, this process, due to technological advances the body of the J20 used a large piece of titanium aluminum monolithic ingot casting, extrusion through a dedicated press to increase the density, ( two years before the successful development of this machine, once the media has been reported, this aircraft fuselage press is developed specifically for J20) and finally adopted the hollowing out of the CNC machine tools, and this is a ** type, high-precision CNC machine tools. titanium aluminum castings (diameter could reach more than 3 meters) hollowed out into the shape of the aircraft fuselage section, so that aircraft do not need to cover the processing of the framework of the skin, body and skin are that a titanium aluminum alloy ingots into the J20 simply do not see the rivets. This process can be a substantial increase in aircraft strength, and accuracy of processing also increased a lot, this is a revolutionary step forward in the process of aircraft fuselage. Aircraft in the past is a step by step to build up, the first structures of titanium aluminum alloy frame, perforated between the framework and tighten the bolts, then the rivets riveting the skin. These processes completely by hand, the precision is difficult to control, and which bolt riveting tight or aging may lead to the disintegration of the entire aircraft, light can lead to skin cracking, so planes have to do static destructive testing to verify aircraft to meet the design strength. J20 because of the introduction of new processing technology, the entire body is one, to achieve the best strength, after the air to do maneuver led to the disintegration of the fuselage will no longer appear. J20 in the fuselage surface in fuselage processing only paste the stealth patch, we note the following diagram, the J20 stealth patch pieces pasted a bit like a submarine sound-absorbing rubber. If you later piece of stealth patch off just paste a new on OK, the maintenance of such aircraft is very easy. J20 of the overall processing technology is currently the world's first application in the aircraft, F35, or are relying on the rivets riveting, not to mention the Russian T50, 20 years ago technology, fundamental and J20 did not comparable sex. Said an aircraft's advanced not just look at the surface, J20 designed for strategic need (to carry large amounts of fuel to increase the range and large anti-ship missiles) into a long body, such a body if the old process of the previous processing that we are The naked eye can not think the proportion of its body does not, the body too long, the body the middle of the weaknesses of the stress, the most easily broken, but this shortcoming after the introduction of new technology completely eliminated. J20 had just come out of foreign aircraft design experts feel that incomprehensible, but once you understand the process, doubt it will become clear. Secret: F-20 stealth fighter 360-degree omni-directional reflector radar Department First we look at a diagram: see figure 1 this is reflected in the schematic diagram of the aircraft in the level of 360 degrees within the Department of reflection radar (Airborne radar band, cm band), which is the stealth aircraft "direction" stealth aircraft under normal circumstances, only consider the level of 360 degrees within the Department of reflection radar. From the figure, we can see, the non-stealth aircraft omnidirectional reflector radar system are relatively strong 25dBsm about stealth aircraft in all directions in a very small angle range only a strong reflection of radar waves Department, other most of the range of angles of the reflected wave strength below-10dBsm (the RCS unit dBsm to the conversion formula of m ^ 2: σdBsm = 10lgσ-10dBsm about 0.1m ^ 2). This chart also reflects the stealth aircraft stealth, by the radar to concentrate reflection to a handful of very small angular range, so that the enemy can not see you in the vast majority point of view, the moment strongly in the minority point of view "reflective", the radar can not effectively detect and lock. So we see the top view of the outline of the stealth aircraft to pursue each other parallel to the edge, so that scattering becomes along the cross section of diffraction in the air background, and an acute angle cross section designed to parallel, scattering and diffraction direction tends to the same war opportunity to reflect the radar signal in a particular direction, so that your radar can be captured fighters signal is a specific direction of reflection, to seize the only moment of its signal angle of a RCS drastically reduced, then you radar screen occasionally flashes a signal that can not be locked, and military exercises of NATO F-15 had the F-22 in the visual range radar signal is still flickering unable to crawl This is the reason . J-20, to borrow Russian friends paralay, publicly shared on the network chart analysis: see figure 2 from the point of view this map, the J-20 to 10 waves of the Department of belly is not clear, all-moving vertical tail parallel situation is not clear, and clear may be increased to 12 wave, 10 wave relative to the increase in F-22 to eight wave wave-based wing in front of two edge.
MiG-29
Banned Idiot
The article says, the J-20 uses virtually no rivets thanks to a modular design, however this if true is not unique
The F-35 assembly line will be notable for its automation, reduced tooling, and virtual elimination of hammered rivets. The subassemblies will be loaded into simplified tooling capable of building any of the F-35 variants
Rivet elimination according at least to western specialist is not total at least current aircraft will use them
September 9, 2008 An aircraft is held together by hundreds of thousands of rivets. Fully automatic machines install rivet holes and rivets with precision in numerous materials. A new hybrid technology combines this mechanical joining technique with adhesive bonding. The lighter an aircraft is, the less fuel it consumes. Given the need to cut carbon dioxide emissions, this is a key aspect of materials research. Aircraft manufacturers are therefore pinning their hopes on particularly lightweight construction materials. These include not only lightweight metals, but also fiber composite plastics, particularly carbon-fiber reinforced plastics (CFRPs). Whenever two CFRP components have to be joined together, this has so far been accomplished primarily by riveting.
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materials. “But the aviation industry is not yet ready to rely exclusively on bonded components and assemblies,” says Klapp. This is why the engineers are exploring the potential of hybrid joining – a combination of riveting and a special bonding process................................
“It’s true that riveting will not be eliminated from aircraft construction in the next several years,” says Klapp. But the aviation industry will soon be unable to manage without structural bonding of primary structures such as the airframe, the wings and the tail units.
To know up to what extend the J-20 does not use rivets is hard to know due to the dark paint, similar to S-37 you can not see on the Su-47 where it has rivets so easily
[video=youtube;HHfKNClaUWQ]http://www.youtube.com/watch?v=HHfKNClaUWQ[/video]
unless you see Su-47 up close or without paint you can see the rivets
[video=youtube;aRDqzwiSkHI]http://www.youtube.com/watch?v=aRDqzwiSkHI&feature=related[/video]
Read the rules concerning BOLD TEXT!
bd popeye super moderator
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can you give me a link to that Tianlong paper? A translation maybe?
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