• Tuesday, July 23, 2019

Chengdu J-20 5th Generation Aircraft News & Discussions

Discussion in 'Chinese Defence Forum' started by lawxx, May 30, 2011.

  1. ChineseTiger1986

    ChineseTiger1986 ELITE MEMBER

    Messages:
    22,060
    Joined:
    Jan 27, 2010
    Ratings:
    +12 / 38,267 / -1
    Country:
    China
    Location:
    Canada
    Xi Yazhou is probably under probation, since the Chinese government doesn't like the make up story to mislead the netizens.
     
    • Thanks Thanks x 4
  2. Asoka

    Asoka FULL MEMBER

    Messages:
    742
    Joined:
    Dec 1, 2010
    Ratings:
    +0 / 1,879 / -7
    Country:
    Canada
    Location:
    United States
    Some people just don't have great logical deduction skills, not even intuition. One telltale sign is ignore some pieces of critical evidence, even after they have been pointed out and emphasized repeatedly. It's one thing, those evidences were not noticed before, it's entirely different when they are ignored. I find liberal minded people tends to have this tendency.
     
    Last edited: Dec 8, 2016
    • Thanks Thanks x 5
  3. ChineseTiger1986

    ChineseTiger1986 ELITE MEMBER

    Messages:
    22,060
    Joined:
    Jan 27, 2010
    Ratings:
    +12 / 38,267 / -1
    Country:
    China
    Location:
    Canada
    China's third generation superalloy DD9 for the WS-15.

    090455c2pussrp6z4hc3nq.png
     
    • Thanks Thanks x 7
  4. Tiqiu

    Tiqiu FULL MEMBER

    Messages:
    967
    Joined:
    Nov 1, 2015
    Ratings:
    +9 / 4,065 / -1
    Country:
    China
    Location:
    Australia
    PL-15 (see post 6856#)
    Also the Russian RVV-BD and KS-172 were said to have 150 km (direct shot) and 400 km (under cruise gliding profile) reach.
    Your source?
    I think until the time we can all agree on this, we have to live on how to disagree.
     
    • Thanks Thanks x 9
  5. randomradio

    randomradio BANNED

    Messages:
    6,991
    Joined:
    Feb 14, 2016
    Ratings:
    +12 / 4,738 / -29
    Country:
    India
    Location:
    India
    Salyut's AL-31FMx series produce 14-15 tons of thrust.
     
  6. samsara

    samsara FULL MEMBER

    Messages:
    1,956
    Joined:
    Oct 28, 2016
    Ratings:
    +5 / 6,032 / -0
    Country:
    Lao Peoples Democratic Republic
    Location:
    China
    pakistanipower, I did you a service... the above-mentioned post #6856
     
    • Thanks Thanks x 5
  7. Beast

    Beast BANNED

    Messages:
    15,396
    Joined:
    Feb 5, 2011
    Ratings:
    +6 / 37,424 / -38
    Country:
    China
    Location:
    China
    No, if that is so, they will not have problem for PAFKA.
     
    • Thanks Thanks x 3
  8. Tiqiu

    Tiqiu FULL MEMBER

    Messages:
    967
    Joined:
    Nov 1, 2015
    Ratings:
    +9 / 4,065 / -1
    Country:
    China
    Location:
    Australia
    歼-20具备超一流的空战能力(中)
    原创 2016-11-23 92军迷 刀口谈兵


    军迷朋友们请点击⬆️⬆️"刀口谈兵"的蓝色字关注我们,并欢迎大家转发朋友圈,传播正能量!

    商务、投稿专用微信号:dktbmsz 欢迎投稿及合作!

    作者:刀口团队 \ 92军迷


    附上期:

    歼-20具备超一流的空战能力(上)

    上一篇我们谈了四代机特性里的前两个S,隐身 和 超音速巡航。具备超音速巡航能力在空战中的意义,需要我们细心琢磨与体会。“在巡航段飞得快”仅仅是其中的一小部分。空空弹虽然标着最大速度4M.,过载35--40G,射程几十公里,而战机最大只能飞9G,但并不是被导弹瞄上就必死无疑?如果是这样运输机装上大雷达,配上远程空空弹,岂不是可以猎杀战斗机?

    其实空空弹的最大速度是在动力段的后程,近距弹的动力段只有十几秒,之后就是无动力飞行。最大过载是导弹第一次机动时鸭翼或燃气舵,使导弹产生的瞬间转弯的加速度,但是随着机动过程,导弹的速度和能产生的过载都急剧下降,有效射程也就大大缩短。相比之下四代机有强劲的动力,无论是在中距拦截,还是近距格斗的空战中,超巡带给空空导弹初速度的增加,不仅扩大了不可逃逸的距离,还使得空空导弹可高机动的次数增加。

    有资料显示,当目标机做4G过载机动时,导弹需要三倍加10G,即3X4+10=22G才可能击中目标,所以0.9M.的三代机发射的导弹,实际上只有一次较大过载修正航行的机会。用中距弹拦截四代机除非是迎头攻击,22Km内有可能击中;如果是侧向或尾追攻击,四代机自身可以在1.5M.的超音速状态下完成6G的机动动作,从而确保甩掉对方的导弹追加。这是四代机绝杀三代机的关键性能,也是超音速机动的基础之一。

    这期我们接着聊第3个S:超机动性能。先看下图,无论是在跨音速区,还是在超音速区,5G机动下F-22都完胜F-15和F-35。

    [​IMG]

    能超巡说明飞机的升阻比和推重比等关键性能达到优秀,同时,这两者也是影响超音速机动的关键。没有高的升阻比和推重比,一机动就掉速度还如何做到超音速机动?所谓的超音速机动性能,是指某个机动动作的全过程是在超音速的状态下完成的。高速机动时不仅仅是可动翼面增加阻力,由于飞机在高速改变姿态,机身和大面积的主翼所带来的阻力增加也大大增加。只有高推重比的发动机才能抵消超音速状态下机动所带来的巨大阻力,

    能保持超音速机动就可以在缠斗中,比三代机更快地抢占有利位置,就像赛车和小货车在复杂的S形赛道里追逐,显然是赛车轻易地把小货车甩在后面。同时,在空战中超音速平台发射的空空弹能做更多的机动,让三代机无法逃逸,而己方却可以利用超音速机动摆脱三代机发射的空空弹。

    所以说超音速机动的关键还是发动机和气动控制,歼-20如果没有推比十的四代发动机,就不仅仅是无法超巡,超音速机动性能也同样不具备,一做大幅度机动就掉速度。既无法超巡又不能超音速机动的歼-20,能让空军的马司令给出“非常满意”的评语吗?如果是那样,歼-20肯定不会到珠海表演,也不会小批量入列,而是继续试飞、直到达标才能够通过技术定型。

    无论是毛发党、还是它的变种“国产毛发”党、以及“太行党”,都认为可以用三代发动机给歼-20定型,以后再换上WS-15。可是它们没有一个能回答这样一个问题,那就是用三代发动机如何能飞出超音速机动?飞不出又如何知道所定型的气动控制和机体的结构强度,是能够满足更换WS-15之后超音速机动的要求呢?

    [​IMG]

    要想拥有一流的超音速机动性能,除了有四代发动机的强劲推力,以及相应的机体结构强度做基础,还至少要有两个因素:超常规的可控翼面矢量喷管。先看下图,歼-20有一对世界上最大面积的鸭翼和一对全动尾翼,而且可偏转的角度惊人,还都是差动的哦,即两对翼面的偏转角度和方向是不同步的。歼-10A的鸭翼就已经是可差动的,而欧洲双风的鸭翼却是无法差动。

    歼-20的鸭翼离气动重心远、其力臂要比F-22采用的平尾长得多,全动尾翼的面积更不是F-22长条形的尾舵可比。即使是偏转相同的角度,对飞机产生的力矩显然歼-20要大得多。主翼的前后襟翼歼-20和F-22都是可以差动的,2001号机起飞前经常要做一套复杂的“广播体操”,在空中这八个翼面组合出的复杂动作,能让歼-20飞出梦幻般的机动性能。

    [​IMG]

    为什么歼-20要采用这样一套非常规的布局,不是611所的设计人员喜欢鸭翼,或像张局说的是双发歼-10,而是被空军给逼的。空军的招标书要求:即使是在矢量喷管失灵的情况下,歼-20的机动性也要达到F-22的水平。601所即使是修改后的三翼面方案也无法达到这一要求,更何况它当时还不能保证能在规定的时间内完成复杂的飞控设计。611所不但选择非常规布局,而且对鸭翼和升力体的预研扎实,而且总师杨伟更是国内顶尖的飞控大师,当场表示可以立军令状,所以成飞夺标是顺理成章的。

    [​IMG]

    [​IMG]

    摄影技术不高、或者是在这之前、之后按下快门,那怕是相隔一点时间都捕捉不到,为什么既然平飞又为什么要有一边喷管是偏转的呢秘密就在下图,这是司马兄在上面那幅图之后,继续连拍的三个瞬间。显然在喷管偏转之后,这架歼-20的机身开始先右侧倾斜,接着尾翼稍稍向右偏转(使飞机右转弯),同时鸭翼也是稍稍向上偏转(爬升),于是歼-20做了个向右的小半径上升盘旋动作。

    民航机在空中做小半径转弯也会这样倾斜,战斗机更是如此,因为侧身后可以通过襟翼偏转帮助转弯。不会是机身保持水平来转弯,那样就只能全靠尾舵的力矩,无法小半径转弯。无矢量推力的战机是靠左右襟翼差动来带动飞机侧身,在慢速通场的情况下显然没有矢量推力来得敏捷,而且徒增阻力。由于歼-20做这个动作机身只需倾斜不大的角度,所以矢量喷管的偏转也只是维持很短的时间。在前往珠海之前,刀大就嘱咐要盯着歼-20的屁股多拍几幅照片,司马兄出色地完成了任务,这幅图被多个网站转载,在此为我们的军迷摄影大师点赞、鼓掌

    [​IMG]

    如果觉得上述的图片解说是脑补,那接着看下图。在这次航展上中航发集团的展馆里,有个“发动机全权限数字电子控制系统仿真试验”的展台,在展台右侧有三个液压作动筒(下图右),而且它们是用过的。它就是拼图(下)矢量喷管装置中用来调节“转向控制环”的A9作动筒(红色箭头所示)。问现场的工作人员:我们的矢量喷管装置成熟了吗?回答:“早已成熟、已经有型号在用”。 追问是什么型号,回答:这个不能说。其实不说也知道,对吧。

    [​IMG]

    下图(上)是2101号机的机尾清晰图,仔细看就能发现:图中2101号机的右边发动机喷管是向右偏转的,其指向(绿线)与飞机的中轴线有夹角。拼图(下)是2015号机和2101号机拍摄角度相近的图,对比一下可以发现红框里的喷管是偏转的。如果认真细看以上的三组证据之后,还坚信歼-20不具备矢量推力能力,那我也无语了。

    [​IMG]
     
    • Thanks Thanks x 6
  9. Tiqiu

    Tiqiu FULL MEMBER

    Messages:
    967
    Joined:
    Nov 1, 2015
    Ratings:
    +9 / 4,065 / -1
    Country:
    China
    Location:
    Australia
    原本歼-20为珠海航展准备了五六分钟的表演,可是来的间谍太多,最后遗憾地只飞了一分钟,稍稍地展示了一下歼-20水平小半径转弯和一个S形机动,以及无加力的垂直爬升。“炮楼”上就有来自日本的空军退役军官,他拍摄的歼-20飞行视频要比央视播放的那段更精彩。

    下图是之前网上一段视频里歼-20的飞行轨迹示意图,当时歼-20垂直爬升后做了一个高速的小半径后空翻(称作“猫鼬”)。图中的绿色菱形代表歼20,黑色圆圈代表逼近的空空导弹。歼-20通过高过载的“超级猫鼬”不仅能甩掉尾追的导弹,还迅速地将机头指向敌机,进入攻击战位。

    [​IMG]

    上周网上流出一段航展前歼-20在成都的飞行视频,其中同样是做了“超级猫鼬”动作,最后还做了个急速横滚三周,而且还不是我们平日里看到的绕纵轴横滚,有点漂浮不定的感觉。可惜我们无缘在珠海现场看到这套原本要表演的精彩动作,这些动作仅仅靠可动翼面是无法完成的。由于有八个可差动的翼面和可差动的矢量喷管,决定了歼-20优异的机动性能,当然还要有极其复杂的飞控做“大脑”。

    F-22当年就是因为担心飞控技术难以达到要求,才选择较为保守的布局,反正对付三代机有绝对的优势。这里面既有当时美国人信心满满的主观因素,也有20年前飞控技术限制的客观原因,总之美国在分析了歼-20的各种飞行图片和视频之后,估计情报人员的后背在冒冷汗。

    由于有高速机动的飞行性能要求,四代机就需要采用侧杆操作,下图显示头戴四代多功能头盔的飞行员,右手正握着侧杆,座椅后面的两个液压作动筒也清晰可见。因为四代机能达到6G的超音速机动,此时座椅的靠背必须可自动向后仰,只能把操作杆设计在右侧才能操纵自如。所以采用侧杆设计是四代机高机动性的要求。但是不能倒过来说,采用侧杆的就一定具备超机动性,如F-16是侧杆却没有超机动性。

    [​IMG]

    这么清晰的图片绝不是卧草、爬树党所能拍

    [​IMG]

    [​IMG]

    通常说的“超机动”可以分成两大类,超音速机动 超常规机动,所以又有5S之说。超音速机动前面已经说了是在超音速的状态下完成的机动动作;超常规机动则是指飞行的轨迹很怪异,飞机的姿态超出了常规的飞行状态,而且通常是在非超音速下完成的,其中按照机动时飞机的飞行速度是高速 还是 慢速,又分成两类。比如苏35能做出超级眼镜蛇、落叶飘、磨盘、弗罗洛夫法轮、吊钟等一般战机无法做到的动作,就把它说成是苏35具备超机动能力,进而误解为是四代机里的一个S。其实它仅仅是超常规机动中的一类,是属于速度较慢的,表演起来很带劲、实战意义却不大。严谨的表述应该是苏35具备“过失速的超常规机动”。

    另一类超常规机动是在维持高速飞行的状态、或速度改变很小的情况下完成的动作。这类动作不会拿来表演、也不吸引眼球。举个例子,它能做到战机的指向与此时战机的飞行轨迹有个夹角,相对于飞机的中轴线来说,此时飞机不是向“前”飞,有点像在泥泞的路上急刹车时,车子向侧滑的状态。开车出现侧滑很危险,战机在空中能这样飞则很有实战价值,相当于把三代机里的高瞬盘和高稳盘给统一了,三代机两者是无法兼顾的。

    多篇论文表明歼20不仅有60°迎角飞行可控、并可支持空战机头指向能力的要求,并且在引入矢量之后,最大可以进行80°迎角的可控飞行。通过分析,歼20凭借较大后掠角、小展弦比的机翼,大长细比的机身、以及较大放宽静稳定度的鸭式布局,获得了优秀的超音速能量机动特性。凭借鸭式边条翼的多涡系耦合诱导出极大的升力系数,获得了极高的亚、跨音速机头指向能力,在超视距拦截和近距离格斗中都可以获得极大的优势。
     
    • Thanks Thanks x 6
  10. randomradio

    randomradio BANNED

    Messages:
    6,991
    Joined:
    Feb 14, 2016
    Ratings:
    +12 / 4,738 / -29
    Country:
    India
    Location:
    India
    Salyut lost to Saturn for the PAK FA's engines.
     
    • Thanks Thanks x 1
  11. Deino

    Deino INT'L MOD

    Messages:
    6,776
    Joined:
    Nov 9, 2014
    Ratings:
    +8 / 9,690 / -0
    Country:
    Germany
    Location:
    Germany

    Guys ... could You please at least add a reasonable English translation or summary ?? The forum rules say clearly the main language is English, so please !!!

    Deino
     
    • Thanks Thanks x 2
  12. 52051

    52051 FULL MEMBER

    Messages:
    1,066
    Joined:
    Sep 9, 2016
    Ratings:
    +1 / 3,453 / -4
    Country:
    China
    Location:
    China
    This article is about the performance of J-20.

    The author believe, even without the WS-15 engines, J-20 can still do dog-fight very well.

    The reason is because during the J-XX bidding phase the airforce set a very high performance bar:

    PLAF's requirement is: the J-XX must satisify the requirement that even if the fighter is not installed with vector-thrusting engine or if the vector nozzle fail to function, J-XX must still have comparable maneuverability to that of F-22 with vector-thrusting engines.

    Due to this very high requirement, SAC's J-XX proposal use 3-wing (Su-30MKI-like) design but even with 3-wing design, SAC is not sure it can deliver the required performance on time, and nor it is sure that it can develop the highly sophosticate flight contorl system properly.

    Yet due to extensive research in canard layout, CAC's proposal can satisify the requirement through means of adopting the biggest front wings among all canard designs in the world, and allow de-coupling front wing control(European canards cannot do that), and a pair of very large and fully-movable tail wings to further increase the control moment.

    And Chief designer of CAC, Yang Wei, is an expert in flight-control system, he is confident that he can develop the highly sophosticate flight control system in time,and thats why airforce pick CAC's proposal.

    So with CAC's extensive research in canard design and Yang Wei's expertise in flight control system, the J-XX bidding become an easy victory for CAC, and they do deliever their promise on time despite the doubts from SAC.

    And Airforce chief Ma is now very satisified with J-20's progress and performance, J-20 with today's underpower engine can still do very well in dog-fighting and the only thing lack is super-crusing, however J-20 today has very huge space to store internal fuel and has a very long combat radius, much longer than F-22, thats why the PLAF decided to deploy J-20 now, even without the targetting engine.

    The author of this article is a very famous Chinese military insider, his online name is Daokou (means: edge of a blade), he is the first one who claimed that China was developing an anti-ship ballastic missile, and this happened in 1990s.

    He is the son of a senior PLAN general.
     
    Last edited: Dec 8, 2016
    • Thanks Thanks x 14
  13. Tiqiu

    Tiqiu FULL MEMBER

    Messages:
    967
    Joined:
    Nov 1, 2015
    Ratings:
    +9 / 4,065 / -1
    Country:
    China
    Location:
    Australia
    images.jpeg

    Could @Asok be the white knight once more?

    Actually my point is people advocating for the use of the Chinese engines would not be so unwise to put every thing they have got on the line. And even they were, they certainly would not have chosen the bet on the J-20 with which the secret could not kept for long. There is no needs in this, it is not the end of the World for the PLAAF even the Russian engines are still used for J-20.
     
    • Thanks Thanks x 6
  14. Beast

    Beast BANNED

    Messages:
    15,396
    Joined:
    Feb 5, 2011
    Ratings:
    +6 / 37,424 / -38
    Country:
    China
    Location:
    China
    They could have ask Salyut to provide the engine but what we know from the process of PAFKA. The whole project looks stall.

    There is no evidence Salyut provide or sell the so called powerful 147kn thrust to China. As I say if there is, there will not so much noise of Su-35 sales to China for the engine.
     
    • Thanks Thanks x 3
  15. Tiqiu

    Tiqiu FULL MEMBER

    Messages:
    967
    Joined:
    Nov 1, 2015
    Ratings:
    +9 / 4,065 / -1
    Country:
    China
    Location:
    Australia
    How do you know he is the son of a senior general?
     
    • Thanks Thanks x 1