Military Review

Flat nozzle for Russian combat aircraft: from Soviet developments to perspective

103

I will take the liberty of speculating on the prospects of introducing into the military Aviation RF planes and drones equipped with engines with a flat nozzle. I will try to understand this issue and share my conclusions.


Flat nozzle design advantages


Since about the 80s of the last century, aircraft designers have discovered a number of advantages for military aircraft engines, which can bring the use of a nozzle with a flat cross-sectional shape.

On the one hand, such a design feature improves the take-off and landing performance (CV) of the aircraft and makes it more maneuverable.

And on the other, it allows the combat vehicle to become less noticeable to the enemy radar. This is because the contours of an axisymmetric nozzle of circular cross-section are very difficult to coordinate with other structural elements of the aircraft to make the aircraft not so noticeable to radars. This is much easier to achieve if you use a flat "jet" nozzle. In addition, in order to further reduce the radio sensitivity, in the manufacture of such a nozzle, materials capable of absorbing radiation are used.

Additionally, the infrared radiation of an aircraft using this nozzle shape is also reduced. This allows you to achieve a ratio of the height and width of the nozzle, significantly reducing the temperature of the outgoing jet.

Of course, this form of nozzle also has drawbacks. Firstly, when switching from a circular cross section of the engine to a rectangular nozzle, some pressure loss occurs. At best, about five percent is lost. The second disadvantage is the need to increase the stiffness and strength of the nozzle, since a design of this shape experiences a greater load than a round nozzle.

But all these disadvantages more than overlap with the benefits.

The first Russian plane with a flat nozzle


Flat nozzle for Russian combat aircraft: from Soviet developments to perspectiveThe first aircraft in the world where a new idea was realized was the American F-15, which performed its first experimental flight in 1988. Later, flat nozzles began to be used in stealth aircraft F-117 and F-22 Raptor. Although in Russia the introduction of flat-section nozzles into military aviation took up almost simultaneously with the Americans, we lagged behind in this area. And not because our experts are worse than the American ones, it was just that difficult times began in the USSR: the collapse of the Soviet Union almost led to the complete destruction of the country's defense industry. It was simply not up to the planes then, frankly.

During its sunset, the Soviet Union was on the verge of mass production of a new generation fighter equipped with a flat nozzle engine. It was originally called the Su-27KM. The aircraft began to develop in 1988. Formally, it was considered a modification of the Su-27K ship fighter (“M” is “modernized”). But at its core, it was a completely new development. Its main features were the wings of variable sweep and two engines with one common flat nozzle. This nozzle shape made it possible to reduce IR visibility and simplified thrust vector control. For some reason, the project was closed in 1989 (this is a separate история) In 1990, the prototype became a flying laboratory. Everything was going well, the plane performed very well during test flights, but due to the collapse of the USSR and the ensuing crisis in all areas, including the defense industry, all work had to be curtailed. There is a continuation of this story, but it no longer applies to the use of flat nozzle engines in Russian aviation.

Flat nozzle engines today and tomorrow


For a long time, Russian aircraft manufacturers did not return to the use of a flat nozzle. Most likely, there were reasons for this. But more recently, it was decided to return to this idea.

This is due to the creation of the first Russian fifth-generation fighter Su-57. I will not dive into the long and dramatic history of the creation of the aircraft. Firstly, it has not yet ended, and secondly, this is a separate topic, which in a nutshell cannot be revealed.


I will only mention moments regarding the possible use of engines with a flat nozzle in this aircraft.

As you know, the development of the Su-57 has been going on for many years, since the beginning of the 2000s, and the transition to serial production has been postponed many times. Initially, the first planes were planned to be transferred to the troops back in 2015. And although last year the first production Su-57 fell during the tests, experts consider this combat vehicle to be very successful. There are already several prototypes, more than a dozen. This is proved by the fact that in August 2018 the Sukhoi Design Bureau received a contract from the Russian Ministry of Defense, according to which the Russian military should receive 2020 Su-2027 aircraft from 76 to 57, not counting the two more ordered earlier.

The fighter parties that will enter service will be equipped with already existing AL-41F1 serial engines with an axisymmetric round nozzle section. Similar power units are installed on the Su-35S. Su-57 fighters with such engines will be delivered to the troops tentatively until the mid-2020s.

And then instead of this engine, the so-called “Product 57” will begin to be installed in the Su-30. Little is known about its technical characteristics, but according to some data a flat nozzle will be used in it. Actually, this was to be expected. But taking into account the fact that the developers' plans and terms may change several times, it is difficult to say exactly when the Russian military will have combat aircraft equipped with engines with a flat nozzle. At the same time, it is worth saying that not so long ago there appeared images of the model of the “Hunter” UAV, the nozzle of which was exactly flat.
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  1. Vladimir_2U
    Vladimir_2U 15 May 2020 06: 41 New
    13
    collapse of the Soviet Union
    Not collapse, but destruction.
    Well, it is not said that a flat nozzle allows only a vertical deflection of the jet.
    1. Volodin
      Volodin 15 May 2020 06: 59 New
      +6
      Quote: Vladimir_2U
      Not collapse, but destruction.

      What's the difference. They ruined the country - a fact.
      It is unlikely that this is a topic for discussing terminology in this material.
      1. Vladimir_2U
        Vladimir_2U 15 May 2020 07: 18 New
        -7
        Destroy and collapsed itself - just a huge difference. Any objections to the nozzle? hi
        1. Volodin
          Volodin 15 May 2020 08: 19 New
          +6
          Quote: Vladimir_2U
          Destroy and collapsed itself - just a huge difference.

          Well, if we talk about terminology, that is, such an option to "collapse and self-destruct" is a huge difference ... I don’t understand who here says that the country itself collapsed? ..

          Regarding the nozzle - the author wrote his article, if you write and offer your own - I will read it with pleasure.
          1. Vladimir_2U
            Vladimir_2U 15 May 2020 08: 58 New
            -2
            I wrote about a flat nozzle, and you are not a word.
            1. Volodin
              Volodin 15 May 2020 09: 08 New
              +1
              Quote: Vladimir_2U
              I wrote about a flat nozzle

              Well, therefore, a start has been made. Reading your article would still be more interesting than five words about a flat nozzle in a comment - a problem that had been solved long ago.
              1. Vladimir_2U
                Vladimir_2U 15 May 2020 09: 10 New
                -1
                Do you make a living writing articles? Me not.
                Quote: Volodin
                a problem that has long been resolved
                Well, just decided, then why this article and what is its value?
                1. Volodin
                  Volodin 15 May 2020 09: 22 New
                  +5
                  Quote: Vladimir_2U
                  Why is this article and what is its value?

                  Write to the author, suggest the option to never write materials again. Perhaps he will take note.

                  But I personally am still going to wait for a valuable article from you, because authors often write articles not because of a desire to earn money, but because of a desire to share their point of view.
                  1. Ka-52
                    Ka-52 15 May 2020 10: 05 New
                    +7
                    but because of the desire to share their point of view.

                    point of view should be disclosed. The author of this article could not convey to the readers what he wanted to say. It seems that the author worked out the obligation, and not on his own initiative wrote
                  2. Voyager
                    Voyager 17 May 2020 13: 28 New
                    +2
                    Alexey, do you find this article valuable? It is strange that the above points and the author’s opinion, without any supporting facts, generally passed moderation here.
      2. Ros 56
        Ros 56 15 May 2020 08: 31 New
        -6
        So you have to run, once the country has been ruined. Join your company.
        1. Volodin
          Volodin 15 May 2020 08: 42 New
          +7
          I suppose you have already joined this company? Only in this case, do not equal yourself, please ...
          1. Ros 56
            Ros 56 15 May 2020 08: 50 New
            +5
            And I’m supposed to run from there with some bumps; it’s not bad for me at home. I don’t whine that everything was lost, the chef is leaving, the plaster is being removed. Yes, there isn’t enough money, sometimes we’re clutching with my wife, here we have to fix the car, so what, that’s what you say. Live in Japanese - not nada tarapisa, not nada valnavasa. fellow lol hi
            1. Volodin
              Volodin 15 May 2020 09: 01 New
              +6
              Quote: Ros 56
              And I’m supposed to run from there with some bumps; it’s not bad for me at home.

              Well, why then do you advise me with this “bumblebee” here?
              1. Ros 56
                Ros 56 15 May 2020 09: 11 New
                -6
                What's the difference. They ruined the country - a fact.

                From this very thing, how can one live in such a country, all that remains is to leave or strangle oneself.
                1. Volodin
                  Volodin 15 May 2020 09: 19 New
                  +1
                  Quote: Ros 56
                  From this very thing, how can one live in such a country, all that remains is to leave or strangle oneself.

                  For starters, you would at least take a closer look, or something ... about the collapse and the grave of which country we are talking about. Then they would have commented. Or are you still in the USSR, unlike the other 250-odd million of its citizens ...
                  1. Ros 56
                    Ros 56 15 May 2020 09: 24 New
                    +2
                    Here you are weird, comrade. In fact, the Russian Federation is the successor of the USSR.
                    Let's end here.
                    1. Volodin
                      Volodin 15 May 2020 09: 37 New
                      10
                      Quote: Ros 56
                      In fact, the Russian Federation is the successor of the USSR. Let's end this

                      No, really. You wrote an insulting comment to me, without even bothering to figure out what was going on. Now you offer to finish it all.

                      And here is the Russian Federation and where does the succession, if it was a question of the collapse (destruction, grave - call it whatever) of the USSR?

                      I was born in the Soviet Union. When I was in school, the country in which I was born was gone. I live in Russia. And now someone appears who also tells me that “it’s time to run” with some kind of painted compass.
                      1. shahor
                        shahor 15 May 2020 13: 59 New
                        +3
                        Quote: Volodin
                        I was born in the Soviet Union.

                        I was also born and lived in the USSR. Now this country is gone. We live in Russia, and we need to think about how to create decent living conditions in our country. Tired of the endless moaning that in the USSR the sun was shining brighter and the girls were more beautiful. We were younger, hence the brightness of the lighting. But the USSR remained in history. Sadly, in a manly way.
                2. Roman123567
                  Roman123567 15 May 2020 09: 58 New
                  -3
                  money is not enough, sometimes we’re clutching with my wife, here’s the car

                  So this is nifiga not life .. Why haven’t been strangled so far ..))
                  1. Ros 56
                    Ros 56 15 May 2020 11: 36 New
                    0
                    I will leave this pleasure to you and see. fool
                  2. Sidor Amenpodestovich
                    Sidor Amenpodestovich 15 May 2020 12: 13 New
                    +3
                    Because needs are always ahead of opportunities. Money is only enough for some billionaires, like Abramovich or Bezos.
                    Do you think that if a man has a salary of five hundred thousand, then he does not think about money? He also thinks no less than Ros56.
                    This conditional peasant, and his family, respectively, if there is, just life is more expensive. Apartment, cars, clothes, leisure, a trendy school for children, etc.
                    And these loans are also often taken.
                    So very many will have to choke.
                    1. Ros 56
                      Ros 56 16 May 2020 16: 37 New
                      +2
                      It was Sidor who, for this purpose, I threw a bait and the conclusion is simple, the bulk judges by itself and does not reach many that money is not the main thing, there is never a lot of money, and even millionaires abuse their wives. Primitive thinking and nothing can be done about it.
        2. Maki Avellevich
          Maki Avellevich 16 May 2020 11: 08 New
          +1
          If you like this cartoon so much, then one dog is missing there.
          If Satire then to the end.
    2. Avior
      Avior 15 May 2020 07: 31 New
      0
      Do you know how the F-22 got around this problem?
      The nozzles were set at an angle to each other.
      1. Vladimir_2U
        Vladimir_2U 15 May 2020 07: 33 New
        +2
        Quote: Avior
        The nozzles were set at an angle to each other.
        And how does it work? Only traction control comes to mind.
        1. Avior
          Avior 15 May 2020 07: 55 New
          0
          I read for a long time, I write from memory, now I rummaged and found nothing on this subject, I already doubted whether I had misled you or whether my memory had failed me. It’s just that once in my head it was delayed.
          Now there’s just no time to dig, I’ll see for dinner.
          Sorry if misled.
        2. Avior
          Avior 15 May 2020 09: 43 New
          +3
          Sorry, I misled you.
          I looked carefully, did not find anything, not a word about this anywhere.
          They are even visually on the F-22 in the same plane.
          Maybe there are a couple of degrees there purely for technological reasons, but obviously not for what I wrote. I don’t know why it once was postponed for me.
          request
          1. Vladimir_2U
            Vladimir_2U 15 May 2020 09: 44 New
            0
            C'mon, the question is unprincipled. hi
          2. gridasov
            gridasov 15 May 2020 10: 26 New
            +3
            No, this is not technological distraction. With a moving stream you need to work like an intellectual product. This means that if you set the corners correctly, then two capacious and monolithic jets merge into one monolithic stream. They literally swirl the overall flow from two sides radially opposite. Why is this happening? Because a new fractal dynamic structure is being formed with its own energy potential. By the way, at that time V. Schauberger on this occasion recommended that other engineers study the structure of the urination organ and not only the boar.
          3. ver_
            ver_ 22 May 2020 10: 41 New
            0
            ... toilet paper never comes off in holes ..
      2. Ka-52
        Ka-52 15 May 2020 07: 39 New
        +9
        Do you know how the F-22 got around this problem?
        The nozzles were set at an angle to each other.

        Yes, they did not solve any problems. Only not much improved their impact on handling. It’s just that the Americans didn’t set the task for the engine and gas speakers to make these nozzle characteristics the same as the full-fledged UVT. In the case of the F-22, the deviation of the nozzle in the vertical axis only helps to partially compensate for the lack of control planes at large angles of attack.
        1. Avior
          Avior 15 May 2020 09: 45 New
          0
          I rummaged now, and generally did not find anything about it. Memory failed, it turns out.
          One evening I’ll rush carefully.
      3. EvilLion
        EvilLion 15 May 2020 08: 32 New
        +1
        On the Su-57, in fact, the engines are at an angle, in the photo below it is clearly visible.
    3. Ka-52
      Ka-52 15 May 2020 07: 32 New
      11
      Well, it is not said that a flat nozzle allows only a vertical deflection of the jet.

      not only vertical, but also synchronous. It has not yet been said that a flat nozzle has a larger mass than a Laval nozzle.
      Firstly, when switching from a circular cross-section of the engine to a rectangular nozzle, some pressure loss occurs

      it’s more correct to say not pressure but traction. When passing beyond a kink, large gradients of gas-dynamic parameters (pressure, density, velocity) arise. The resulting shock waves destroy the boundary layer and disrupt the flow structure of the supersonic jet of gas flow. And thrust, as we know, is the ratio of the flow rate at the inlet and outlet
      1. Vladimir_2U
        Vladimir_2U 15 May 2020 07: 35 New
        0
        Quote: Ka-52
        not only vertical but also synchronous
        It’s not entirely clear, only one way, one corner and at a time?
        1. Ka-52
          Ka-52 15 May 2020 07: 52 New
          +7
          It’s not entirely clear, only one way, one corner and at a time?

          exactly. I think that due to the structurally close proximity to each other, the meaning in the dilution of thrust vectors is lost
        2. Avior
          Avior 15 May 2020 09: 44 New
          0
          while they write that no more than 20 degrees.
      2. Victorio
        Victorio 15 May 2020 09: 56 New
        +6
        Quote: Ka-52
        it’s more correct to say not pressure but traction. When passing beyond a kink, large gradients of gas-dynamic parameters (pressure, density, velocity) arise. The resulting shock waves destroy the boundary layer and disrupt the flow structure of the supersonic jet of gas flow. And thrust, as we know, is the ratio of the flow rate at the inlet and outlet

        ===
        ) at home, while repairing the bathroom, the ventilation pipe was taken out of the toilet through the bathroom. First I tried a pipe of rectangular cross section, less size and visibility. but settled on a round, higher traction and less noise
        1. Vladimir_2U
          Vladimir_2U 15 May 2020 10: 03 New
          +1
          But the visibility on the enemy radar jumped sharply! good
    4. Bar1
      Bar1 15 May 2020 07: 50 New
      +5
      At the same time, it is worth saying that not so long ago there appeared images of a model of the “Hunter” strike UAV, the nozzle of which was exactly flat.


      so where is this photo? Show...
      1. vVvAD
        vVvAD 15 May 2020 21: 22 New
        +1
        so where is this photo? Show...

        The author did not point to the photo, but to the “image” - one of the early 3D UAV models. Of course, in the photo of the first test sample, hung with a bunch of sensors, such a nozzle cannot be, because it simply is not in the metal. Used serial engine (AL-31F, it seems? Correct, if not right). But this does not mean that it will not appear in pre-production and serial equipment.
    5. EvilLion
      EvilLion 15 May 2020 08: 33 New
      +4
      I'm afraid that it is the collapse, because 95% of the causes are internal.
    6. Mavrikiy
      Mavrikiy 15 May 2020 09: 22 New
      0
      This allows you to achieve a ratio of the height and width of the nozzle, significantly reducing the temperature of the outgoing jet.
      Oh how. And reducing the temperature of the jet will not reduce the thrust of the engine? repeat
    7. merkava-2bet
      merkava-2bet 15 May 2020 10: 49 New
      +5
      Who said that only in the vertical plane, look at a bunch of patents on the topic of two-dimensional flat nozzles, the simplest scheme, a household air conditioner with a two-dimensional movable damper, another thing is the price of the issue, that is, the loss of the gas path, the author Pavel Bulat has a very good job topic nozzles and losses in them.
      1. Vladimir_2U
        Vladimir_2U 15 May 2020 11: 05 New
        +1
        Quote: merkava-2bet
        the author Pavel Bulat
        Thank you, excellent articles, we will read! Plus to you!
  2. Ka-52
    Ka-52 15 May 2020 07: 07 New
    +8
    The title is intriguing, the topic is interesting (he understood it for a long time and returned more than once), but the article .... brief theses and finish. What is it then? .... sad
  3. The leader of the Redskins
    The leader of the Redskins 15 May 2020 07: 18 New
    +3
    But how to react? Judging by the text, a flat nozzle is still a Soviet operating time.
    Here in VO this is often reproached. Like they finish the Soviet backlog. Especially if someone "finishes" not in our country.
    1. Ka-52
      Ka-52 15 May 2020 08: 07 New
      +4
      But how to react? Judging by the text, a flat nozzle is still a Soviet operating time.
      I remember articles in TsAGI on the gas-dynamic characteristics of a flat and asymmetric nozzle I came across dating back to the early 80s. And the F-22 with a flat nozzle flew, as we recall, only in the early 90s
  4. Al Asad
    Al Asad 15 May 2020 07: 27 New
    +8
    And why didn’t they show the photo?
  5. Victorio
    Victorio 15 May 2020 07: 33 New
    0
    Of course, this form of nozzle also has drawbacks. Firstly, when switching from a circular cross section of the engine to a rectangular nozzle, some pressure loss occurs. At best, about five percent is lost. The second disadvantage is the need to increase the stiffness and strength of the nozzle, since a design of this shape experiences a greater load than a round nozzle.
    ====
    it is obvious maneuverability goes by the wayside, because there is no longer the possibility of nozzle movement in two (horizontal and vertical) and more planes
    1. Kalmar
      Kalmar 15 May 2020 09: 04 New
      +3
      Quote: Victorio
      visible maneuverability fades into the background

      There is an opinion that she leaves. Modern missiles are capable of maneuvering with overloads, which, in principle, are unattainable for a fighter, both with and without high-explosive. Under these conditions, it is much more expedient for a fighter to “swing” stealth, electronic warfare equipment, and the like.
      1. Victorio
        Victorio 15 May 2020 09: 46 New
        +2
        Quote: Kalmar
        Quote: Victorio
        visible maneuverability fades into the background

        There is an opinion that she leaves. Modern missiles are capable of maneuvering with overloads, which, in principle, are unattainable for a fighter, both with and without high-explosive. Under these conditions, it is much more expedient for a fighter to “swing” stealth, electronic warfare equipment, and the like.

        ===
        the way it is. but it seems that the pilot is better that she, maneuverability, was
        1. Kalmar
          Kalmar 15 May 2020 10: 24 New
          -1
          Quote: Victorio
          the way it is. but it seems that the pilot is better that she, maneuverability, was

          I don’t argue, but there’s already a question of a technical compromise: how maneuverable the aircraft should be and how much for its sake one should sacrifice other characteristics (the same stealth). In the end, a flat nozzle does not mean that the plane will only fly in a straight line.
      2. +5
        +5 15 May 2020 16: 31 New
        +2
        Then the F-117 or B-2 is a super fighter? ETOGES which EW station can be squeezed into it, and how many missiles ....
        that's just like the recently old Su-24, and 30-40 years ago not shining maneuverability against the background of the then-missiles, evaded the Turkish 120th .... you know the firing of air-launched missiles not only at point-blank range, but with a tendency to increase missile ranges launches - and even more so.
        1. Kalmar
          Kalmar 15 May 2020 17: 02 New
          +1
          Quote: 5-9
          Then the F-117 or B-2 is a super fighter? ETOGES which EW station can be squeezed into it, and how many missiles ....

          In the F-117, as far as I know, you just do not squeeze anything in particular, is too small. B-2, on the contrary, is too healthy; it’s hard to hide. And if, in addition to jokes, I fully admit that the fighters of the future will be clumsy bumps against the background of the present, but hardly noticeable and densely packed with various high-tech defense and attack means.

          Something similar happens in strategic aviation: at first they were chasing altitude and speed, and now, with the advent of long-range missiles, old people like the B-52 or Tu-95 are gaining a second youth.

          Quote: 5-9
          recently the old Su-24, and 30-40 years ago not shining maneuverability against the background of the then-missiles, evaded the Turkish 120th

          Are you talking about this episode: https://eadaily.com/en/news/2020/02/22/sbit-rossiyskiy-su-24-v-idlibe-pytalis-tureckie-voennye-versiya? Well then MANPADS, obviously flawed cheap rocket.

          Quote: 5-9
          firing urmv you know not only point blank happens

          Here, as I understand it, the question is not only in range. The main thing is that the rocket has a reserve of fuel for sharp maneuvers by the time it draws closer to the target. And twirling somersaults, when another 50 kilometers to the rocket, is of little use.

          Well, in summary, I emphasize: I do not say that maneuverability is not needed at all. It’s just that her role is no longer as high as it once was.
          1. Avior
            Avior 15 May 2020 21: 44 New
            +1
            With a missile defense maneuver, speed is drastically lost.
            When launching a pair of rockets in one gulp with a small gap, if you leave the first, the second will fly when you are in a helpless state
  6. Aviationism
    Aviationism 15 May 2020 07: 38 New
    +8
    A flat nozzle is a minus for a maneuverable fighter. Sukhoi studied it and did not accept it. For a bomber or non-maneuverable drone, it is justified. Geometric stealth has limited utility.
  7. AlexVas44
    AlexVas44 15 May 2020 07: 42 New
    +2
    ... flat nozzles ...

    Nice passage. The section is flat, but the shape of the nozzle can be as a result of this section round, rectangular, square, oval, etc. Although it is clear what is meant, but if the article is in a technical format, apparently, it is not necessary to make such a mixture with cross-section and shape. Annoying.
  8. Ross xnumx
    Ross xnumx 15 May 2020 08: 06 New
    +3
    I respect other people's work (+).

    But in general, I note one important fact. In the days of the USSR, there were many different developments in connection with a large number of design bureaus. Most likely, the regime of secrecy did not allow a wide acquaintance with them by an idle public, and after the absence of specialists it was not possible to understand the content and even the meaning of the developments. Today, pulled out of the coffers, they are presented to us as some creations of advanced military science. But the extended periods from the sketch to the finished product only confirm my assumptions.
    And, as it turned out, the Russian flat nozzle grew back in the USSR.
    1. Ka-52
      Ka-52 15 May 2020 08: 42 New
      +6
      But in general, I note one important fact. In the days of the USSR, there were many different developments in connection with a large number of design bureaus. Most likely, the regime of secrecy did not allow a wide acquaintance with them by an idle public, and after the absence of specialists it was not possible to understand the content and even the meaning of the developments. Today, pulled out of the coffers, they are presented to us as some creations of advanced military science. But the extended periods from the sketch to the finished product only confirm my assumptions.
      And, as it turned out, the Russian flat nozzle grew back in the USSR.

      this is demagogy. First, development should be in demand. In the 80s, flat nozzles were evaluated on the basis of the requirements of those years - they had no idea of ​​"stealth" then. Then there was the motto: "Faster, higher, more maneuverable." A flat nozzle is not a child prodigy - it has a lot of flaws and not so many advantages. It works only in relation to a specific strategy. Now we have grown to this concept. Now they turned to him. You have lost everything and politics again "at the top of the page."
      1. Servisinzhener
        Servisinzhener 15 May 2020 10: 31 New
        +2
        It works only in relation to a specific strategy.
        I think this is the use of low-visibility strike drones. To destroy air defense or objects with air defense in the area of ​​operation?
        1. Ka-52
          Ka-52 15 May 2020 11: 14 New
          +6
          Not only. All means of delivery and destruction, in which instruments can be used to reduce visibility in the radar and visible spectrum: UAVs, bombers, attack fighters and ammunition. The breakthrough of layered air defense is the main goal of these funds.
          Although this strategy is becoming obsolete. Apparently, a more fashionable strategy is now coming to the fore - minimizing and cheapening the means of destruction, which allows them to increase their density indefinitely. Everything goes to the appearance of clouds of unmanned swarm vehicles, which stealth is not particularly needed. They are effective in their mass character.
  9. egor1712
    egor1712 15 May 2020 08: 25 New
    +6
    Bullshit, all these arguments about the visibility or invisibility of the device due to the shape of the nozzle.
  10. EvilLion
    EvilLion 15 May 2020 08: 30 New
    13
    A flat nozzle is needed for one thing only - reduced visibility. With an increase in the quality of sensors, this advantage disappears. Cons remain. That is why no one else suffers such garbage, and this nonsense will never appear on Russian planes.

    As for the UAVs, they have completely different speed indicators, which means completely different parameters of thermal radiation, and traction loss for them m / b is less critical, to compare this with a fighter that spews blue torches from itself is somehow strange.
  11. Free wind
    Free wind 15 May 2020 08: 33 New
    0
    First of all, it seems necessary to detect an object going into the attack, from the frontal projection, and when the plane has already fired. Let's say from 100-150 km and leaves, it is already problematic to get it from the ground.
  12. rocket757
    rocket757 15 May 2020 08: 48 New
    0
    Many, many lost ... almost lost the country, offensive yes!
    However, we do not have to compete with anyone now, but work calmly according to real, feasible plans .... add a little more, a little previous enthusiasm and inspiration, for the speed of project implementation and .... we will achieve what we need.
  13. gridasov
    gridasov 15 May 2020 09: 00 New
    +2
    the higher the flow velocity of the moving flow, the higher the observed elasticity properties of this flow. Well, this is so for those who are not familiar with the physics of high speeds of hydro-hydrodynamic flows. Therefore, in airplanes and rockets, not just a nozzle is needed, but the so-called short and dense trace of gas escaping from the nozzle. the so-called Mach rings talk about this, and in rocket exhaust they go back to the new phase 0. Therefore, to reduce the trace of exhaust, it is necessary to significantly accelerate the gas at the exit from the nozzle. How to do this due to the gas itself? Physicists know that in the near-wall zone the flow velocity is orders of magnitude lower than in the central part of the jet. But physicists do not know that energy parameters as a complex of dynamically changing parameters should be the same. Therefore, you need to know that in the central part the flow vector is with one dominant, and in the wall perpendicular to the central part. Therefore, at this difference, the flow can be significantly twisted and, so to speak, in amateurish style. That is, the higher the flow rate in the linear vector, the higher the spin speed. Moreover, this should occur according to dimensional algorithms at each stage. Therefore, I recommend that Russian scientists turn to Sagov’s patent or to us to understand what a nozzle with a self-swirling flow should be exactly at the exit of the nozzle. And as a conclusion, the gas flow at the exit of the nozzle has a dimension of impulse in terms of circumference. Therefore, it should remain round for many reasons.
    1. Ka-52
      Ka-52 15 May 2020 09: 14 New
      +4
      Therefore, you need to know that in the central part the flow vector is with one dominant, and in the wall perpendicular to the central part. Therefore, on this difference, the flow can be significantly twisted and, so to speak, in amateurish style

      Everything is disgusting to the contrary. As the flow moves in the outlet, the channel narrows and the pressure increases. At the point at which the pressure changes upward, a compression wave begins to form, with a vector directed away from the channel axis. As you move forward, the pressure increases, so does the angle of deflection of the compression wave. Thus, an oblique shock wave (or plane shock wave) is born, which destroys the boundary (laminar) layer that runs along the nozzle wall. The resulting vortex flow has a lower velocity than the main one. This leads to a drop in traction.
      1. gridasov
        gridasov 15 May 2020 09: 27 New
        +2
        You are saying everything correctly. Besides, I understand what you are talking about. only I did not tell you that the flow is conical, and therefore the destruction of the laminar layer occurs inside the stream. And it is very difficult to detect it visually or by thermograms. Moreover. The mathematical technology for the analysis of turbulent flows is based on the construction of algorithms and data at each point of local space. Therefore, I knew in advance that someone who knows was sure to note the continuity of the flow. This is our invention, that at all stages of the flow movement there is an increase in energy extremes, which means everything should be structurally optimally simple. And if this is disgusting to you, then probably your achievements are more convincing and there are no problems.
  14. Ingenegr
    Ingenegr 15 May 2020 10: 09 New
    0
    Thesis number 1:
    Since about the 80s of the last century, aircraft designers have discovered a number of advantages for military aircraft engines, which can bring the use of a nozzle with a flat cross-sectional shape.

    On the one hand, such a design feature improves the take-off and landing performance (CV) of the aircraft and makes it more maneuverable.

    Thesis number 2:
    Firstly, when switching from a circular cross section of the engine to a rectangular nozzle, some pressure loss occurs. At best, about five percent is lost. The second disadvantage is the need to increase the stiffness and strength of the nozzle, since a design of this shape experiences a greater load than a round nozzle.

    Somewhat opposite theses. I do not take into account the incomprehensible "there is some loss of pressure." Pressure of what and where? Rather, we are talking about reducing thrust compared to an axisymmetric nozzle while maintaining the parameters of the working process. So, a decrease in traction is unlikely to make the aircraft more maneuverable and even more so will not improve its HPH.
    1. Ka-52
      Ka-52 15 May 2020 10: 16 New
      +3
      Somewhat opposite theses. I do not take into account the incomprehensible "there is some loss of pressure." Pressure of what and where?

      Forgive the author for incompetence in such matters. The essence of the jet nozzle is that in it, as the gas jet moves, it expands. In this case, the pressure and temperature drop (pressure drops in principle, without any influence of the shape of the nozzle itself), and the speed increases up to supersonic. Therefore, the author’s words about the effect of pressure are not right here. But the thrust really falls. Why - I wrote above.
  15. JonnyT
    JonnyT 15 May 2020 10: 09 New
    +2
    The highly controversial claim that a flat nozzle provides better maneuverability.
    It was precisely because of this that they abandoned the flat nozzle, because you can’t deceive much in the “dog dump” on a flat, and it’s difficult to implement control
  16. Alecsandr
    Alecsandr 15 May 2020 10: 28 New
    0
    The future belongs to unmanned robotic airplanes with unbelievable speed and overloads, and then all EPR and any form of nozzle disappear. The main thing will be to hit the target both air and ground almost instantly. Air defense systems will also switch to other physical principles. Maybe laser or some other. Already, the transition to hypersonic speeds of aircraft shows in which direction aviation and rocket science will develop. The pilot is becoming superfluous. The battles will be controlled by the young generation, who are now sitting behind the clavs. He is playing virtual igry.Prochital rassmeyalsya.Vo and what I am dreamer.
  17. Andrey.AN
    Andrey.AN 15 May 2020 10: 31 New
    0
    The efficiency of a jet stream and its cooling rate in air should be directly related, why then fence the garden, put engines with less thrust and all that’s why bother to kill the thrust with a flat nozzle?
  18. Andrey.AN
    Andrey.AN 15 May 2020 10: 49 New
    0
    Now, if a super-maneuverable Su-57 is better suited to actions at low speeds and feels more comfortable at low thrust, then it is more prone to thermal stealth.
  19. Taoist
    Taoist 15 May 2020 11: 05 New
    +2
    After the development and implementation of an all-angle nozzle, in general, there’s no sense in continuing to engage in flat ... From the gain, only a slightly reduced visibility in the radio range from the back hemisphere ... Everything else is in the minuses ...
    1. vVvAD
      vVvAD 15 May 2020 21: 15 New
      0
      After the development and implementation of a multi-angle nozzle, in general, continuing to engage in a flat sense makes no sense ...

      Well, why? And if you manage to combine a round all-angle nozzle with a flat? A couple of years ago, there was an article in the VO stating that the product 30 for the Su-57 will have an all-round circular nozzle (which everyone knows already), and also that it can take a flattened shape when not rejected.
      Those. the plane when flying in a straight line (conditionally) will be able to reduce its thermal signature.
      1. Taoist
        Taoist 16 May 2020 20: 16 New
        0
        To reduce the thermal signature, there are a bunch of less costly methods (which also do not harm traction)
        1. vVvAD
          vVvAD 17 May 2020 20: 41 New
          0
          Who argues? But an additional way to reduce the vehicle in addition to the existing ones will reduce it even more, and decently (given the non-linear dependence). This is probably why they did not ignore such an opportunity. Well, to reproduce American know-how at a slightly different technological level, even at the technology demonstrator, will be very indicative for the developers of this know-how.
  20. Hermit21
    Hermit21 15 May 2020 11: 05 New
    0
    The flat nozzle has its pros and cons. It all depends on the customer’s TTZ
  21. Shadow041
    Shadow041 15 May 2020 11: 14 New
    +1
    A typical plane with a flat nozzle F-22 and there is far from everything is as good as it seems to the author. The vertical nozzle does not interfere with the vertical maneuver, but it interferes with the horizontal maneuver as well ... So in pursuit of phantom stealth, a plane with a flat nozzle loses its maneuverability
  22. Undecim
    Undecim 15 May 2020 11: 27 New
    0
    On the one hand, such a design feature improves the take-off and landing performance (CV) of the aircraft and makes it more maneuverable.
    The flat nozzle itself does not affect either take-off and landing performance, nor maneuverability. For this, as for any other nozzle, it is necessary to control the thrust vector. Moreover, it is much more difficult to realize the UHT on a flat nozzle, since only the horizontal flaps of the nozzle can be changed, and, accordingly, the direction of the thrust vector can only change in the vertical plane. Changing the direction of the thrust vector in the horizontal plane is possible only on a twin-engine aircraft by using reverse devices in combination with the different-sized movement of the nozzle flaps of adjacent engines. Experiments of this type were performed on the F-15 STOL / MTD (pictured).
    1. Undecim
      Undecim 15 May 2020 11: 30 New
      +2
      For the above reason, the same F-22 UVP is carried out only in the vertical plane at +/- 20 degrees.
  23. Undecim
    Undecim 15 May 2020 11: 41 New
    0
    During its sunset, the Soviet Union was on the verge of mass production of a new generation fighter equipped with a flat nozzle engine. It was originally called the Su-27KM. The aircraft began to be developed in 1988. Formally, it was considered a modification of the Su-27K ship fighter (“M” is “modernized”). But at its core, it was a completely new development. Its main features were the wings of variable sweep and two engines with one common flat nozzle. This nozzle shape made it possible to reduce IR visibility and simplified thrust vector control. For some reason, the project was closed in 1989 (this is a different story). In 1990, the prototype became a flying laboratory. Everything was going well, the plane performed very well during test flights, but due to the collapse of the USSR and the ensuing crisis in all areas, including the defense industry, all work had to be curtailed.
    Then the author got confused and misinformed the reader. The Su-27KM never had a reverse sweep wing, and its prototype was not a flying laboratory. He had a reverse sweep wing.

    The general public, this aircraft is better known as the Su-47, "Golden Eagle". The only copy is in the museum LII them. Gromova.
    1. Undecim
      Undecim 15 May 2020 11: 45 New
      +1
      And for testing a flat nozzle, the serial Su-27UB was used, which was converted into a flying laboratory LL-UV (PS) or Su-27PS. On the left engine (AL-31F) a flat nozzle of the development of the Ufa NPO Motor was installed with the possibility of changing the direction of the thrust and reverse vector. 20 flights were performed and positive results were obtained.

      In general, the author should prepare articles on complex technical issues more carefully.
  24. Gust
    Gust 15 May 2020 13: 11 New
    +3
    Well, it remains only to add that the F-35 uber plane, where stealth is one of the key parameters, has a round-shaped nozzle.
  25. Rostislav Prokopenko
    Rostislav Prokopenko 15 May 2020 15: 47 New
    0
    The dispute in the comments suffered over bumps and gully ...
    In the article I did not see a comparison (and the possibility on a flat nozzle) of the controlled thrust vector.
    Maybe with the maneuverability our SUSHKI possess and the hell with them - with the advantages of a flat nozzle?
  26. Operator
    Operator 15 May 2020 19: 10 New
    +1
    A flat nozzle sucks, it does not provide any of the alleged effects described in the article (especially, it reduces the radar visibility).

    The only thing that is achieved by a flat nozzle is a decrease in the temperature of the gas jet by increasing its perimeter (increasing mixing with air) and, therefore, the infrared visibility of the aircraft in the rear hemisphere.

    In all other respects, the round nozzle steers.
  27. Kushka
    Kushka 15 May 2020 22: 10 New
    0
    Kettle's opinion: flat "nozzle" - worse
    if the enemy kills me with his fist
    from my "nozzle" will remain. But if I have
    square "nozzle", so little remains of it
    fist.
  28. Black Colonel
    Black Colonel 15 May 2020 23: 08 New
    +1
    I read about flat nozzles in the journal "Aviation and Cosmonautics" in the early 80's. There, control of the thrust vector was considered differently than it is now.
    Still, a flat nozzle can change the thrust vector only in one plane, and a round nozzle, like on our fighters, can change this vector in any direction. In my opinion, a round nozzle in terms of maneuverability is more promising. A flat nozzle provides more stealth. So what will be in the priority of the created aircraft, the nozzle will be preferred by the designer.
  29. Kushka
    Kushka 15 May 2020 23: 49 New
    +1
    Here is my "Moskvich" round nozzle (Soviet operating time).
    So friends will send for “one more” - you saw this maneuverability!
    And stealth! - not one inspector noticed!
    They sent me for one! And I told them - but there wasn’t one!
  30. Vladimir SHajkin
    Vladimir SHajkin 16 May 2020 02: 21 New
    0
    A flat nozzle reduces thermal inconspicuity, I think that if you modify it with combustion, then it will reduce the axisymmetric one, but if you control the plane, maneuverability doesn’t add and you have to work on the glider.
  31. Voltsky
    Voltsky 16 May 2020 10: 10 New
    0
    why a flat nozzle ?! If the efficiency is much less, infrared visibility is not much less, the ability to reflect amy compared to the ribbed nozzle is debatable.
  32. gorunov
    gorunov 16 May 2020 15: 29 New
    +1
    And by chance, not because of the raptor’s flat nozzle, the deflected thrust vector is only up and down?
  33. gorunov
    gorunov 16 May 2020 15: 41 New
    +1
    In the case of a flat nozzle, OBT control is possible only along one axis, we lose super-maneuverable capabilities along the yaw axis.
  34. Alexander Khodov
    Alexander Khodov 17 May 2020 00: 39 New
    0
    “On the one hand, such a design feature improves the take-off and landing performance (HPC) of the aircraft and makes it more maneuverable.” Why on earth does it improve when, due to traction losses caused by such a design, these performance characteristics deteriorate?
    "Its main features were the wings of variable sweep and two engines with one common flat nozzle." Not a variable sweep, but a reverse one (well, not wings, but wing then)))
  35. olshome18
    olshome18 17 May 2020 14: 09 New
    0
    It's time to apply and triangular.
  36. Zhevlonenko
    Zhevlonenko 18 May 2020 12: 23 New
    +1
    A flat nozzle imposes restrictions on maneuverability, and since stealth was not at the forefront for our designers, maneuverability was preferred.
  37. Mister who
    Mister who 19 May 2020 19: 29 New
    0
    You are kidding, what maneuverability - let's say in afterburner)) the plane cannot be rotated 90 °, it can also rotate 90 °, but the flight path will not change much, what about inertia? and take a rocket explosion with the spread of shrapnel of large radius, no maneuverability will help you. Who first spotted fired rockets and in full steam, he won. And preferably in an unmanned version.
  38. Mister who
    Mister who 19 May 2020 19: 50 New
    0
    It’s interesting an unmanned high-altitude aircraft like a rocket - whether it will be the 5th-6th generation.))
  39. Berg berg
    Berg berg 9 June 2020 21: 21 New
    0
    Russian planes will not have a flat nozzle, it’s just the last century and the waste material. All the same, Russian engines on military equipment are the best, the West quietly and viciously admires them, and they will be even better!
  40. ilik54
    ilik54 27 June 2020 18: 58 New
    0
    Airplanes of the future will have the ability to take off and land vertically using a screen effect. And they will fly in a cloud of plasma, so that streamlined aerodynamic forms will be unnecessary to them. Such aircraft will have a wide range of movement, from near space, to flights at the level of house roofs.
    Hanging on the spot and turning will be their hallmark in the storming of any objects, together with acceleration to hypersonic speeds in the plasma cloud from the spot.
    Interestingly, in horizontal flight they will be able to change altitude almost vertically, without a gentle descent and ascent.
    This will allow a new wing design, which will have a completely different flight control concept. So, in particular, on it front and back there will be nozzles of the detonation engine, plasma generator, which will allow you to rise and fall vertically, without shifting horizontally.


    In the wing there are detonation engines that are located horizontally, and not, like in the nozzle of a standard engine in a circle, these detonation engines will create traction for the lifting force of the wing of the aircraft. The ekranoplanes have the same system, only there are separate engines in front of the ekranoplan.
    This is how the circuit diagram of the wing of such an airplane looks like, see the diagram -