Military Review

A couple of years before “Berkut”: backward-swept wing and Sukhoi Design Bureau

It often happens that the most famous things in the literal sense are only “the tips of the iceberg”. This situation has developed with one of the most interesting projects of the P.O. Dry. Their experimental aircraft S-37 - aka Su-47, aka "Berkut" - fifteen years ago attracted the widest attention of the public. The main reason for this was an unusual aerodynamic design with a reverse sweep wing. S-37 was predicted a great future, and some fans aviation seriously calculated his chances of “twisting” any enemy aircraft in aerial combat. But from the very beginning, representatives of the Sukhoi firm did not hide the fact that the S-37 is primarily an experimental vehicle and it is too early to try to come up with combat work for it. Moreover, the Su-47 was not the first development of the design bureau, in which the reverse sweep wing was used. However, previous experiments received little publicity.

A couple of years before “Berkut”: backward-swept wing and Sukhoi Design Bureau

In 1979, the State Committee on Aviation Engineering at the USSR Council of Ministers (GKAT) and the Ministry of Defense launched the I-90 program. Her goal was to create a fighter that would serve the country in the 90s. By the year 81, the road map of the works was ready and a preliminary definition of the future aircraft's shape began. After a series of discussions and disputes, it was decided to entrust the main work on the project to the MMP for them. Mikoyan. The head of the State Committee for Aviation Silaev demanded that Sukhoi be connected to work on the I-90 project. However, the management of this design bureau was able to convince the Committee officials that their Su-27 project is not only modern, but also promising. Therefore, to create a fighter of the nineties, the Sukhoi Design Bureau does not need additional work: it will be enough to refine the existing equipment using relatively simple methods. It should be noted that this was the logic and, as it later turned out, the Su-27 family of fighters will serve not only in the 90's, but also years later. At the same time, the State Committee did not intend to leave the Sukhoi company without work. In the same year, 81, she was assigned to prepare a draft of the nineties attack aircraft called W-90.

In the light of all these events, the initiative of the new general designer of the design bureau named after A.G. Dry. Mn Simonov, barely taking over the high post, suggested to start work on a completely new aircraft. The project promising fighter received an index of the C-22. Obviously, the designation similar to one of the versions of the Su-17 project was taken for a reason, and to “disguise” the initiative development. At that time, the world's leading design bureaus once again "hurt" the idea of ​​a backward-swept wing (CRP). Such bearing planes had several features at once, which favorably distinguished them from the classical wing. Back sweep due to specific flow increases the aerodynamic quality of the wing in a large speed range, increases lift, improves takeoff and maneuverability, and also has a beneficial effect on stall resistance. The first experiments in the field of CBS refer to the 40 years of the last century. However, then several design teams were not able to cope with the drawbacks of the reverse sweep. The fact is that with an increase in the flow velocity, an elastic positive divergence of the wing is observed — twisting, which can lead to structural failure. Strengthening the metal power set compensated for the tendency to twist, but negated the entire gain in lift. In addition, the forward sweep wing drag is larger, which is especially strongly felt at supersonic speeds.

The development of the aviation industry in the first half of the eighties of the last century already made it possible to solve most of the problems typical for KOS. Thus, it was proposed to compensate for the deformations of the wing with the use of composite materials, and the propensity of the aircraft to be shaken - with deflected wing toes and overflow. As conceived by the designers of the Sukhoi, these elements of mechanization were to distribute the flows from the wing and the influx so that they did not interact with each other in dangerous proximity to the aircraft. In the middle of 80-x all theoretical problems were solved under the leadership of the chief designer V.S. Konokhov in Sukhoi Design Bureau completed the preparation of a preliminary draft of the C-22 aircraft.

The fighter, made according to the “duck” scheme, was comparable in size with the Su-27 aircraft. Thanks to the new wing and its remarkable prospects, it was possible to equip the 23-ton car with just one dual-circuit turbojet engine. Engineers have already begun to prepare all the documentation for the production of a prototype, when it turned out a few bad details of the project. It turned out that in the country there is not yet such an engine that could single-handedly “pull” a car with such take-off weight, providing it with decent flight characteristics. Additional verification of the project for the purpose of exploring the possibility of alteration for another engine showed a noticeable over-weighting of the fighter. The management of the design office had no choice but to stop the C-22 project and start developing a new aircraft based on it. An updated version of the promising fighter received the index C-32.

The Su-27KM multipurpose carrier-based fighter (later C-32), designed by the OKB Design Bureau. P.O. Sukhoi to equip the Soviet aircraft carrier projects 1143.5 ("Kuznetsov"), 1143.6 ("Varyag") and nuclear 1143.7 (head - "Ulyanovsk"). After the collapse of the USSR, the Su-27KM project in the form of creating a combat fighter was discontinued due to the collapse of the construction of aircraft carriers and financial problems that had arisen, and the topic was transformed into a research paper on the study of the backward swept wing (CBS), during which the copy for static strength tests was completed to the experimental aircraft S.37 "Berkut", now known as Su-47 (photo

MA was appointed chief designer on the C-32 topic. Pogosyan At the same time considered several options for processing C-22. As a result, a twin-engine fighter with a variable thrust vector was considered the most promising. He was supposed to equip with two TRDDF RD-79M 18500 kgf each. These engines were a further development of the Р79В engine, which was supposed to be installed on Yak-141 vertical take-off and landing aircraft. Unlike the original engine, the RD-79M had great traction and a slightly increased resource. However, a number of problems with the creation of a new engine forced a team of engineers under the leadership of Simonov and Pogosyan to reconsider their views on the C-32 powerplant. Now it was proposed to equip the aircraft with AL-41F engines with a design load of up to 18-19 tons. With an acceptable specific fuel consumption, these engines due to thrust made it possible to provide the C-32 with the possibility of a long flight at supersonic speed without the use of afterburner. Another engine of the I-90 program, the MiG 1.44 MFI, was also supposed to be equipped with the same engine.

Extensive use of composite materials in the C-32 design was a result of not only the desire to facilitate the construction. Sukhoi Design Bureau has already had some experience in reducing radar visibility and in the considerations of designers, composites were far from the last. In addition, the final look of the car, including the technological, was influenced by a new ejection seat. The NGO Zvezda proposed a radically new concept of a means of saving the pilot, which, among other things, allowed him to carry more overloads than the old ones. Accordingly, the estimated operational overload has increased, which has required further strengthening of the design. And again rescued composites.

By the beginning of the creation of the C-32, the initiative project of the Sukhoi company was no longer a secret to the leadership of the aviation industry. Therefore, the KB constantly reported on the progress of work to the State Committee. However, in the 1988 year, when the economic situation in the country became far from better and many defense enterprises began to experience serious difficulties, GKAT decided to stop working on an interesting but dubious project in terms of prospects. For the C-32 stood by the sailors. Excellent take-off and landing data - even if it was calculated - could make this plane a great deck fighter. Thus began a new round in the biography of an airplane with a backward-swept wing.

Copyright © Vadim Lukashevich 2008

In the same year, 88, the designers of Sukhoi presented the advance design of the deck fighter Su-27KM. In fact, it was a “hybrid” of the Su-27K (Su-33) and C-32. From the first, almost all onboard electronic equipment and weapons were taken, while the second “shared” the original wing design. Such an original approach to the early creation of a new fighter-batcher led to an increase in the maximum take-off weight. Su-27KM heavyweight almost to 40 tons, which was 7000 kg more than the maximum take-off weight of the Su-33. The springboards of the Soviet aircraft carriers were not designed to ensure the take-off of such heavy vehicles, and the Ulyanovsk, which was supposed to be equipped with steam catapults, was only laid in the 1988 year. A solution was needed that could ensure the normal operation of the Su-27KM on all types of Soviet aircraft carriers. Due to the large take-off weight of the new aircraft had a little lack of thrust-weight. Accordingly, he simply did not have time to gain the speed necessary for take-off until separation from the deck. After several studies and experiments, the designers of the Sukhoi Bureau decided to recommend a so-called for the Su-27KM. ballistic take-off from a springboard. The essence of this method is that the lack of speed is compensated by the high performance of the wing. The ballistic take-off should have been as follows: the aircraft, having gained some of the take-off speed, detached from the front end of the springboard. By inertia, he moves forward and up, simultaneously picking up speed. After passing the top point of the ballistic trajectory, the fighter (horizontal speed is still insufficient for a full flight) begins to lose altitude and continues to move forward. Upon reaching the height of the springboard edge, the aircraft picks up the required speed thanks to the engines operating on take-off mode and goes into horizontal flight. Such a take-off from the deck is possible only in the presence of a forward swept wing. The fact is that in the first phase of the ballistic take-off, the plane reaches such angles of attack at which the classical wing risks falling into stall. In turn, the WWTP has a certain margin of stability and, due to the greater lifting force, it earlier puts the aircraft into a horizontal position. For greater leveling reliability, the Su-27KM fighter received more advanced mechanization than it was at the C-32.

Copyright © Vadim Lukashevich 2008

The Sukhoi Design Bureau has already begun preparing technical documentation for the production of an experienced Su-27KM, but in May the 89-nd Military-Industrial Commission under the Council of Ministers and the Ministry of Defense concluded that the aircraft was too complex for its adoption. The Su-27KM project lost its status as a promising fighter for arming aircraft carriers. Nevertheless, the company "Sukhoi" was allowed to continue work on the CBS on its own initiative and at its own expense. Before stopping the full-fledged state funding, the Sukhoi Design Bureau planned to build two C-32 flight specimens and one glider for static tests at the Irkutsk aircraft factory. However, the closure of the Su-27KM project and the subsequent financial problems of the whole country led to the fact that all the work on the backward-swept wing of the design bureau had to be carried out entirely at its own expense.

As a result, at the very end of the eighties and the beginning of the nineties, the C-32 project was significantly reworked to the state designated C-37. The first flight of this aircraft, also known as the "Golden Eagle", took place on September 24 1997. Thus, the aircraft, the result of Soviet and Russian work on the reverse-swept wing, took off almost 15 years after the start of the first studies. From the very beginning of the flight tests of the C-37, almost none of its creators had any doubts that this fighter was not destined to become a drill machine, at least in the coming years. "Golden eagle" and remained a purely experimental aircraft. In our country, the idea of ​​CBS did not receive further development and the C-32 and C-37 projects, despite a number of technologies that were first applied to them, remained just another interesting idea in stories world aviation.

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  1. Civil
    Civil 7 June 2012 09: 13
    Thus, the aircraft resulting from Soviet and Russian work on the topic of the reverse sweep wing took to the air almost 15 years after the start of the first research. From the very beginning of the flight tests of the S-37, almost none of its creators doubted that this fighter was not destined to become a combat machine, at least in the coming years. "Golden eagle" and remained purely experimental aircraft

    knew but continued to do ...
    1. leon-iv
      leon-iv 7 June 2012 09: 45
      undoubtedly they worked out composites and weapons compartments for our 5th generation
      1. Vadivak
        Vadivak 7 June 2012 09: 59
        Grumman X-29 The test program for the first aircraft was completed on December 2, 1988 after 254 flights, the second aircraft on September 30, 1991, after 120 flights. During the implementation of the program, there were great difficulties in developing an EMF for an aircraft with CBS due to the difficulty of eliminating cross-linking during management. Both aircraft are currently being mothballed at the them. Dryden.

        To the credit of our aircraft manufacturers, all problems associated with countering divergence and the complexity of control laws were successfully resolved in S-37
        1. black_eagle
          black_eagle 7 June 2012 20: 21
          Quote: Vadivak
          To the credit of our aircraft manufacturers, all problems associated with countering divergence and the complexity of control laws were successfully resolved in S-37

          Well, what can be considered a success, the American prototypes also made 354 sorties, this is also a success, and if so, the S-37 is a flying laboratory that goes for certain data every flight, success is not a success here, you just have to check it calculations of smart uncles (and aunts), true success is staging, and since a bunch of the latest materials and components of this machine are reflected in the newest T-50, it’s all the same, no matter how you twist the success, even though you had to sacrifice an unusual wing
        2. saturn.mmm
          saturn.mmm 8 June 2012 15: 07
          Quote: Vadivak
          Grumman X-29 Test program for the first aircraft was completed on December 2, 1988 after 254 flights

          And I also wanted to add, as far as I know, they never reached supersonic speed.
    2. Vadivak
      Vadivak 7 June 2012 09: 47
      The Germans in 1944 worked and launched. ju-287.

      It was created in an extremely short time. At the same time, a non-standard decision was made: to assemble a new aircraft from the components and assemblies of other aircraft at hand. For this reason, the Ju-287 had a fuselage from the Heinkel He-177 bomber, the tail unit from the Junkers Ju-188 and the chassis of the captured American bomber Conver B-24 (it is interesting that when the plant in Dessau, where the Ju-287 was manufactured, was captured by Soviet troops and the Soviet military administration made an attempt to find the blueprints of the aircraft, it did not succeed for a very simple reason - they simply did not exist).
      1. Borz
        Borz 7 June 2012 10: 24
        Oh, but I haven’t seen such a miracle. The agony of the 3rd Reich sometimes gave rise to amazing projects. Thanks for the information, one more white spot has been eliminated. smile
      2. Srgsoap
        Srgsoap 7 June 2012 10: 35
        Thank you for the interesting and useful information. ++++++++
        1. 755962
          755962 7 June 2012 11: 43
          Currently "Berkut" is in the Flight Research Institute named after Gromov (Zhukovsky, Moscow region) But this is not the main thing! Sukhoi Design Bureau won a tender to develop a fifth generation fighter.
          1. patline
            patline 7 June 2012 15: 33
            I wonder if the development of KOS and variable sweep was carried out "in one bottle"? After all, in this way you can get rid of the problems of CBS in supersonic.
            Although there, too, new problems will come out in the form of reliability of the mechanisms for changing sweep.
            And in my opinion, the change in sweep and the development of mechanisms for the "operation" of the wing at various flight modes is the most promising direction in the design of the airframe.
      3. Dust
        Dust 7 June 2012 11: 41
        Something is doubtful if someone had the idea to sculpt a plane without blueprints even from ready-made units! It doesn’t happen - too complicated construction, not a rake ...
      4. Nova
        Nova 7 June 2012 13: 38
        A reworked Arado, if I remember correctly.
  2. leon-iv
    leon-iv 7 June 2012 09: 48
    Gentlemen, how do you like the idea of ​​using CBS on the attack aircraft.
    For but to the sound it will be the best solution.
    1. black_eagle
      black_eagle 7 June 2012 10: 53
      The CBS itself carries a lot of unresolved problems both at subsonic and supersonic, with all the obvious advantages it has a lot of problems, such as "elastic wing divergence", that is, twisting with further destruction, which does not allow using traditional materials: steel, aluminum, titanium, you have to resort to composites, which significantly raises the cost of the airframe, plus a clear advantage at ultra-low speeds and during takeoff and landing, but still low speeds are the element of helicopters, there is nothing to duplicate the same work, in this situation, I see one plus: I flew in, flew quietly, bombed, and washed off with the afterburner)))) The main task of both the C-37 and the X-29 was to check whether such an aircraft could fly at all, and as one of the designers said, I don’t remember exactly who: "At least we proved that he can fly and not bad!" Even with today's development of technology, it is too early to think about a serial aircraft of such a scheme, for our century there is still a traditional layout with a head
      1. leon-iv
        leon-iv 7 June 2012 11: 37
        that is, the question is in materials technology.
        The element of helicopters is another use.
        We need good maneuverability at low speeds. For all altitude ranges.
        1. black_eagle
          black_eagle 7 June 2012 12: 05
          Not only in the materials, but also in the management in particular, these are essentially completely different machines, although who knows, after the Great Patriotic War, one of the generals or marshals said they say "we do not need jet aircraft, for our age there will be enough propeller driven aircraft!" 50s in Korea already the rustle of MiGari 15s induced, and good maneuverability can be achieved with the use of a deflected thrust vector, the most complex wing mechanization, etc. Another thing that guys who can withstand frantic overloads of more than 10g are not enough ... special costumes and training, everything is necessary, the question, as they say, is difficult, but solvable)))))
          1. leon-iv
            leon-iv 7 June 2012 14: 13
            this is precisely noticed now the shunting capabilities of the AB limit only the capabilities of the pilots.
    2. Green 413-1685
      Green 413-1685 7 June 2012 19: 49
      On the attack aircraft just CBS and not needed. One of the main drawbacks of KOS is the design vulnerability, in other words, the qualities that an attack aircraft need — ultimate survivability with a margin of safety in KOS is impossible.
      1. black_eagle
        black_eagle 7 June 2012 20: 22
        Rational and logical! +
  3. Daemonir
    Daemonir 7 June 2012 20: 15
    nothing is done in vain. everything goes to the piggy bank of proven technologies, at the right time and this reserve will be used
  4. PSih2097
    PSih2097 7 June 2012 20: 51
    Chinese "Wunderwaffle", pay attention to fighters and AWACS aircraft:

    1. Civil
      Civil 8 June 2012 07: 49
      here you go ...
    2. core
      core 8 June 2012 18: 55
      I believe. China is able to build a sort of fittings.
      1. edge
        edge 18 June 2012 12: 52
        China can slap anything, there is money. But it’s a problem to develop. They cannot solve the problem of deck catapults, they try to erase either ours or the Americans
    3. speedy
      speedy 8 June 2012 19: 36
      The Chinese smiled, especially the A-50 on deck, thinking big.
    4. edge
      edge 18 June 2012 12: 46
      nonsense ........ but for North Korea would go to protect the coast
  5. mpanichkin
    mpanichkin 8 June 2012 15: 21
    The Chinese love something in the development of something like a Golden Eagle. After all, this is a plane of PRACTICALLY 5go generation!
    1. Black Colonel
      Black Colonel 8 June 2012 19: 00
      Beautiful computer picture!
    2. edge
      edge 18 June 2012 12: 40
      the Chinese have no development, for this we need a school, only a compilation of stolen goods.
  6. saturn.mmm
    saturn.mmm 8 June 2012 15: 28
    Looking at these designs came up with an idea. If you stick a platform on top of two orphaned "Sharks", it will look like this Chinese airbase.
  7. 89651544551
    89651544551 8 June 2012 19: 42
    BEAUTY !!!
  8. Lyp
    Lyp 8 June 2012 21: 56
    Naturally, the Chinese, like other countries involved in the development of their own aviation, have projects with reverse wing sweep. This scheme is very promising, since it turns an aircraft from a scheme with aerodynamic stability, with its large balancing losses of total lift, into an aerodynamically unstable scheme, where all aerodynamic surfaces work to increase the total lift. The flip side of the coin is that control can only be electronic remote control (EDSU), with the obligatory inclusion of the on-board computer in the control circuit. What requires this system of super reliability. If the EMDS is turned off, the pilot cannot take control in any way, since control algorithms are required that exceed the pilot's capabilities and, in general, are independent of his qualifications. Therefore, I think that progress in the development of this kind of aircraft will depend on the development of the BECVM.
    1. Vasily79
      Vasily79 8 June 2012 22: 14
      Tell me, because at that time in parallel, the Migovites were developing a promising model with only the usual wing, what kind of model
      1. mr.Man
        mr.Man 8 June 2012 23: 23
        An interesting glider, but this is just a modernization of the Su-27, the theme of the S-37 ...
        It is a pity if the "return line" is ruined and goes under the American "flounder" ...
  9. Krusko
    Krusko 16 June 2012 17: 52
    It’s a pity that it was not developed. MiG 1.44 shared the same fate ... There remains the hope that there will be money for modernization of the flashes and drying to 35 - ki ... ianche .... otherwise it will be bad for Russia ..