Military Review

Semi-reactive la

On the fiery "Broom"

As you know, the speed of experienced fighters in the early 1940s exceeded the 700-kilometer line, and its further growth was restrained by both insufficient power of the piston engine and a propeller. For the further progress of the Soviet aviation a turbojet engine was required, but it just did not exist, just as there was no light piston engine with a power of more than 2000 hp.

At the same time, there was a certain groundwork for the development of liquid-jet and direct-flow engines (pulsating WFDs appeared later, after the Soviet Union received the captured German materials). These circumstances led to a revival of the idea of ​​designer A.Ya. Shcherbakov on the combined power plant of the aircraft (piston and jet engines). First of all, LREs were considered as accelerators, since very problematic ramjet engines required additional research and development.

Certain hopes were pinned on the LRE RD-1, developed in the Kazan Special Department of the NKVD under the leadership of V.P. Glushko and tested on the flying laboratory Pe-2 with the participation of the joint venture. Queen. The basis for the development of combat vehicles with a combined power plant was the resolution of the GKO from 22 May 1944. According to this document, along with the planes of other designers it was proposed to install the RD-1 on La-5FN. With standard La-5FN armament, the maximum speed of the semi-reactive fighter should have been at least 780 km / h at an altitude of 7000 meters. It should have climbed 5000 meters in 3 minutes (the time of LRE operation) with the range on the main engine - 300 km. The aircraft was required to be built in triplicate, with the first by September 1944 of the year, and the last, with a laminar wing profile, by January 1945 of the year.

Work in this direction began almost simultaneously at the branch of the OKB Lavochkin (Plant No. 81), organized in accordance with the NCAA's order from 22 March 1944, on the territory of the Moscow Plant No. 381, and in Kazan under the supervision of SM. Alekseeva and SP. Queen respectively. Korolev, having taken the La-5FN as a basis, proposed two variants of the “VI” high-altitude fighter: one with three RD-1 LREs installed in the fuselage and wing consoles, and the other with one three-chamber RD-3. According to Sergei Pavlovich, for “VI” it was required to increase the wing area, install a pair of turbochargers TK-3 and four machine guns of the sun X XUMUM caliber mm.

La 7P-2

It was expected that the speed increase of the first version of the fighter will be 100 — 140 km / h, and the second — 215 — 290 km / h, the ceiling will increase by 4000 and 6500 m, respectively. In this case, the duration of the flight at an altitude of 14 km using a piston engine will be within 15 — 20 minutes. But all these projects remained on paper.

At the end of 1943 of the year, the Moscow branch of the design bureau urgently began to refine the La-7 under the liquid-propellant rocket engine V.P. Glushko. The first La-7-1 was built in October, 1944, at plant number 381. In its tail part there was a LPD RD-1, created under the direction of V.P. Glushko, with a pumping system for supplying fuel components driven by the main engine ASH-82FN. The oxidizer tank, containing 270 kg of nitric acid, was located in the center section, and the fuel (60 kg of kerosene) was in the right wing console. At the same time, the supply of gasoline was reduced to 210 kg. The rocket engine control was carried out, like the ASH-82FN - with the help of the gas sector lever and the starting valve (valve).

Factory tests La-7-1 began in late October. A few days later (tentatively at the beginning of November) test pilot A.V. Davydov performed on his first flight. The pace of testing can be judged by the fact that before 24 February 1945, only 15 flights took place, five of them with the inclusion of LRE, after which the aircraft needed repair.

Engine reliability left much to be desired. The reasons for this were enough. First of all, despite the use in the power plant of such acid-resistant materials as pure aluminum and its alloys, as well as stainless steel, aggressive acid, falling on some units and assemblies, mercilessly corroded them, resulting in disrepair.

Flight tests of the La-7-2 with the RD-1 engine began on 26 on January 1941 of the year and continued until March on 27. During this time, 19 flights were performed with an engine equipped with air-to-air ignition. Within two months, the LRE launched 45 times, six of them - in the air, and only two flights made platforms with the removal of the characteristics of the machine.

From 45, the RD-1 launches failed 15 times, of which six were caused by ignition, the combustion chambers changed twice.

The maximum speed increase was about 95 km / h at an altitude of 2600 m. The tests ended on March 27 with a LRE explosion. On that day, the plane, piloted by G.M. Shiyanov, at the height of 6000, the auxiliary engine did not start. Having declined to 3000 m, Georgii Mikhailovich tried again, but an explosion was heard, apparently because of the components of the fuel that had accumulated in the combustion chamber. The elevators suffered the most from the explosion, from which only the rags remained. Slightly better looked steering wheel.

But trouble does not come alone. The cockpit of an almost uncontrollable aircraft was filled with poisonous nitric acid vapors. Only by a miracle the pilot saved the wounded car. More than two weeks it took to repair the La-7Р-2, but the LRE, modified during this time, still did not want to run at high altitudes. Only the use of RD-1 HZ with chemical ignition allowed the launch problem to get off the ground, but it was not possible to increase the reliability of the LRE.

Placement of the LRE RD-1 HZ on the plane La-7Р-2

Understanding the failures with this engine was only possible by the middle of summer, and from July 11 to November 16 1945 completed 14 flights on La-7Р-2. During this time, four combustion chambers and two pumps were changed, 49 start-ups were made, eight of them were in the air. LRE refused to 23 times, of which the fault of the ignition - twice. In five flights, it was possible to perform horizontal platforms with the removal of the aircraft’s speed data. In particular, they registered the maximum speed of 795 km / h at an altitude of 6300 meters. However, it was not possible to make a combat vehicle with LRE 7 from a wooden one.

In the 1945, the “120” aircraft was the faster and therefore the preferred fighter for installing the LRE. However, before installing the RD-1HZ on it, the car had to be thoroughly repackaged and completely replaced the tail part of the fuselage with plumage. In particular, the tank with the oxidizer, as well as on the La-7P, was placed in the center-section, and one of the guns HC-23 was replaced with B-20. The motor AL-83 for centering was shifted forward by 70 mm. Moved to other places battery, oil tank and air tank. There were other, smaller changes.

The “120P” tests were held in parallel with the tests of the La-7Р-2. In addition to fine-tuning the LRE had to tinker with the refinement of the fuel and oil systems of the fighter. Virtually all of the semi-reactive OKB-301 fighters have become flying rocket engine testing laboratories. Even on the last car of sixteen flights with a working rocket engine could only make seven. In one of them, the speed of 725 km / h was recorded, receiving a gain of 103 km / h.

The third aircraft built was a semi-active La-7Р with a single-chamber LRE LS Dushkina RD-ZV. The car was ordered to pass on flight tests in August 1945 of the year, but documents that shed light on its biography could not be found.

Culminating in stories with "120P" became the flight of the pilot A.V. Davydov at the air festival in Tushino in 1946. The “120Р” flights ended on August 13, when due to the ignition of a mixture of fuel components in the engine compartment, the tail rotor of the fuselage and tail unit burned. By this time, the ASH-83 resource was almost exhausted, and the airframe was spoiled by nitric acid.

Tests La-7P-2, manned by G.M. Shiyanov, 27 March ended 1945, the explosion of the LRE

Aircraft "120" with LRE RD-1 HZ

Thus ended the biography of the 120 aircraft, but the idea of ​​using the LRE on the aircraft was not buried. There were no fighter jets in the Soviet Union yet, and the threat from the capitalist world was so great that in order to fight the potential enemy bombers, it was necessary to continue the development of fighters with a combined power-plant.

The last attempt to create an aircraft with the LRE was a project of an all-metal fighter "130Р" with an ASH-82FN engine based on the projected La-9. The layout of the aircraft largely repeated the predecessor - “120P”: in the tail section was installed LRE RL-1HZ, tank with oxidizer - in the center section, and with kerosene - in front of the cockpit. In order to preserve the required reserves of stability and controllability, they increased the area of ​​the tail, and the steering wheel cover and heights were replaced by metal. Of the weapons left only two guns NA-23 with 160 ammunition ammunition. There were other differences from the 130, due to the installation of the auxiliary engine.

In this form, the aircraft began to be built at the experimental plant OKB-301, but in 1946, this topic was closed, though not quite. Ten years later, LRE tried to use interceptors with TRD. But even at the end of the 1950s, when the LRE seemed to be brought on, their “indomitable temper” continued to be felt. In aviation, the “services” of rocket engines had to be abandoned once and for all, except for the American space shuttle vertically taking off. But that's another story.

Between the past and the future

Alternative to LRE could be direct-flow engines (ramjet). Unlike the former, they did not need an onboard supply of oxidizer. If we consider that these liquids (with the exception of liquid oxygen) are very aggressive and toxic, then the operation of the WFD is greatly simplified. In addition, the overall weight of the power plant and fuel decreased, and the duration of the flight increased. But the "forward flow", ready to be installed on the aircraft, was not yet, and those that existed required a long tune.

During the war years, small design teams led by I.A. Merkulov and M.M. Bondaryuk. The first was practicing DM-4 on the Yak-7B fighter, and the BD-1 WFD-3 was to be investigated on the LaGG-1942 flying laboratory of the 105 release of the year with the M-XNUMXPF engine.

I don’t need to stop on the principle of operation of the ramjet, I think it’s not necessary, it is described in literature sufficiently. Note that the studied WFD-1 had a length of 2,15 meter and a diameter of a diffuser 0,14 meter with a weight of 16 kg. About the magnitude of the engine thrust is not known, but recall that it is directly related to the velocity of the air at its entrance.

Before the start of flight tests, the ramjet engine was tried several times on the ground, using another LaGG-3 as a fan. However, the unevenness of the airflow velocity field and the insufficient velocity head allowed to do this only twice, and it was not possible to determine the engine parameters.

Flight research of the engines, which took place in August 1942, was carried out by test-pilot GA. Mishchenko. The speed increase when turning on the ramjet engine turned out to be small, about 15 km / h. Since the task of obtaining maximum speed was not set when the ramjet was turned on, there were no requirements for the aerodynamics of its attachment points to the wing, which “ate” 35 — 40 km / h. The flights showed that before installing a ramjet on a combat aircraft, it is necessary to ensure stable combustion of the fuel with automatic control of the composition of the mixture and the launch of ramjet at high altitudes.

Research and development of the Pndr-430 Bondaryuk engines (WFD-430 with a diameter of 430 mm) was delayed for almost two years. In the spring of 1944, the first option was to install a pair of such engines on an 120 aircraft, and then on the 126 fighter, designated as 164.

Flight tests last began in June 1946. For two months with a little A.V. Davydov and A.A. Popov made a flight on the 164 34 aircraft and in 30 of them launched a ramjet. The reliability of the improved engines, though increased, but they still malfunctioned and required

Aircraft "164" with ramjet-430

vodka. At the same time, improving the aerodynamics of the junctions of direct-flow engines with a wing, together with their increased pressure, made it possible to increase the speed increase compared to an aircraft with a disconnected ramjet engine to 104 — 109 km / h, depending on the flight altitude. In relation to the aircraft without additional engines, this increase was within 62 — 64 km / h.

Compared with the flying laboratory LaGG-3, this was significant progress, especially since it was possible to slightly reduce the drag of the combination of the wing and the power plant. The simplicity of operating the machine was very captivating, and the flight characteristics with operating accelerators remained, as with the 126 aircraft. All this led to recommendations for installing the WFD-430 on the promising fighter "130", which later received the designation "138". In accordance with the resolution of the Council of Ministers of the USSR, the 138 aircraft was supposed to reach a maximum speed of 660 km / h (590 km / h with disconnected ramjet) and 760 km / h at 6400 m (660 km / h - without ramjet), recruit 5000 m in 6 minutes. At the same time, its range must be at least 1100 km in flight at an altitude of 1000 m, and the takeoff and run length must be within 450 meters.

The aircraft was still on paper, and in May 1947 of the year, by order of the ministry, they were obliged to participate in the Lavochkin air parade to complete the flight testing of two copies of the 138 aircraft and to prepare them for July 27. At the same time, the plant manager No. 21 was also instructed to equip ten more La-9 with RD-430 jet accelerators.

The weight of an empty aircraft with constant gun armament increased by almost 200 kg.

An attempt to combine the piston range and speed of jet fighters in the 138 aircraft did not produce the desired result. The range really turned out to be quite good, but the speed left much to be desired. According to the calculation of the “direct flow”, Bondaryuk developed 220 kgf thrust near the ground at an air flow velocity of around 700 km / h. In fact, it was smaller because the 138 was not flying at that speed. Compared with the La-9, the speed at 3000 meters increased only by 45 km / h, although 70 — 100 km / h was expected to be added, but when the ramjet was turned off, it turned out to be 60 — 80 km / h. With all the engines running, the flight range did not exceed 112 km (with normal flight weight), and the duration was 10 minutes.

Ramjet 430 under the wing of the aircraft "164"

Aircraft "164" with ramjet-430

Factory flight tests of the 138, which ended in September 1947, showed that the 138 fighter could fight the B-29 and B-50 bombers, including during pursuit. But in a duel with enemy fighters, both piston and jet, his chances were slim. And although the ramjet engine remained in the experimental discharge, the experience gained during their design and fine-tuning was not lost and was subsequently used to create more powerful engines, including the La 17 unmanned target.

Another direction in the development of combined power plants was the use of two pulsating air-jet engines (DFD), D-9 and D-10, designed by VN on the La-13. Chelomey and intended for cruise missiles (in the terminology of 1940-ies - projectiles), analogues of the German V-1. It’s hard to say whose idea it was and what the authors intended for it. As opposed to ramjet engine, as the speed increases, the thrusters drop and you can only expect a political effect associated with the enormous noise level generated by their work.

The D-10 engines of 200 kgf each were first equipped with training trainers La-7. The first stage of the factory tests, which ended in August 1946 of the year, showed that at 3000 m height, the speed increased by 119 km / h compared to a machine with non-operational RFID. In this case, the maximum speed could not be determined due to the limitations on the velocity head associated with the strength of the aircraft. Yes, and the plane due to disrepair soon written off, continuing research on all-metal La-9. But at the same time, the D-10 engines equipped three Sparky 7 launchers, intended for the 1947 air parade of the year. But the taxpayer never saw them. In November, the 1945 year of testing continued.

Aircraft "138" with ramjet-430

Ramjet 430 under the wing of the aircraft "138"

The leading pilot for this car was N.V. Gavri-lov. But things did not go beyond the experiments.

Especially for the La-9 plant number 51 produced modified engines, received the designation D-13. The same company equipped them with 12 fighters. Additional engines were suspended on pylons attached to reinforced ribs of wing consoles. At the same time, the aircraft fuel system was modified, the horizontal tail and the mounting of the piston engine hoods were strengthened. At the same time, they removed the armor support and two guns, and to maintain the centering, they attached an 82-kilogram load to the ASh-60FN gearbox. Made a number of changes in the equipment of the machine.

In this form, the La 9 group was shown to the country's leadership and the public in Tushino 3 August 1947. Pilot test aircraft pilots NII VVS VI. Alekseenko, A.G. Kubyshkin, L.M. Kuvshinov, A.P. Manucharov, V.G. Masich, G.A. Sedov, P.M. Stefanovsky, A.G. Terentyev and V.P. Trofimov.

After the air parade, one of these dozens of La 9 (La 9РД) was tested at the Air Force Research Institute from November 21 1947 to January 13 on 1948 of the year. The leading test pilot was I.M. Dziuba Flew over the car and test pilot Olga Vladimirovna Yamshchikova. The increase in speed when the auxiliary engines were turned on in comparison with the “clean” 9 X-LUM made 70 km / h, while the installation of the PU-RND “eaten” to 57 km / h. The pilots noted strong vibrations and noise when turning on the scramjet. Engine mounts worsened the maneuverability and take-off and landing characteristics of the aircraft. Engine start-up was unreliable, the duration of the flight was sharply reduced (due to the high specific fuel consumption of the HRVD), operation became more complicated.

La-9 with pulsating jet engines V.N. Chelomey

The work carried out benefited only in the development of engines intended for cruise missiles. Airplanes, participating in air parades, their roar made a strong impression only on the public.

In 1943, TsAGI considered several variants of fighters with motor-compressor air-jet engines (VRMC). Among them was La-5ВРДК, but he, like all the other projects proposed by the institute, only paved the way for the P.O. Sukhoi and I-105 A.I. Mikoyan.

Thus ended the story with the half-reactive fighters S.A. Lavochkin, gone in the past with piston engines. And the planes themselves were on the border between the past and the future of aviation.
Articles from this series:
Achtung! Achtung! In the air La Xnumx
"Standard 1944 of the Year" La-7
Full Metal La-Xnumx
The last piston la fighter
Semi-reactive la
Reactive firstborn Lavochkina
Unmanned aerial vehicles Lavochkin
Rocket "Umbrella" Lavochkin
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  1. svp67
    svp67 25 December 2013 10: 33
    A true story, how our people "tamed the fire" ... good
  2. ramsi
    ramsi 25 December 2013 11: 58
    and here I’m braking all the time, I would like to know a competent opinion: if there was a two-row star on the shopkeeper, then could it really be impossible to make a coaxial screw WITHOUT a reducer? ..
    1. Argon
      Argon 25 December 2013 12: 51
      No, the gearbox as such is required by any engine (with the possible exception of only an electric one), this allows to improve the efficiency of the screw, increase its operating range, for a piston ICE the gearbox is to some extent a flywheel (allowing to stabilize the angular speed of the output shaft) to some extent with a damper ( combining torsional vibrations of the gearbox and K \ B achieve mutual elimination thereof) the mass of this device (as a percentage of the weight of the motor installation) will always be less than a set of measures to ensure the operation of the circuit with two K \ B working coaxially. The most important indicator of the efficiency of the gearbox is the power value ICE spent on its rotation, in gearboxes having a reverse line, it increases so much that the use of such gearboxes is effective only with high-power engines.
      1. ramsi
        ramsi 25 December 2013 13: 25
        thanks, Argon, but too many letters ... I understand - the turbine and the propeller, even if not of a large diameter - the difference in rpm is too great; another thing is a piston engine, after all, the speed can be "adjusted" to the screws with the size of the cylinders and the working stroke of the pistons; technically, to pass the drive from the rear row shaft through the front row does not seem to me an impossible task; and if the synchronization of work is not ideal, then it's not scary
        1. anomalocaris
          anomalocaris 4 January 2014 08: 23
          Will not work. In any case, the optimal rotational speed of the screw will be several times less than the optimal rotational speed of the output shaft of the engine.
          The power developed by the engine is defined as the product of the torque on the shaft and its rotation frequency. Theoretically, these two parameters, for a given power, can be varied as you like, but in practice ... But in practice it turns out pretty sad. With a decrease in the frequency of rotation of the output shaft, the dimensions of the engine and its mass increase, as well as a dynamic imbalance, which forces the use of a very small flywheel.
      2. The comment was deleted.
  3. 0255
    0255 25 December 2013 12: 14
    It is interesting to know about "semi-reactive" aircraft. We are waiting for articles from the author about fully reactive "Lavochkins"!
    In WAR THUNDER, I would also like to put such engines on their "La")))
  4. Argon
    Argon 25 December 2013 12: 23
    In the mid / late 70s, TsAGI conducted a number of studies on applied aerodynamics (together with leading universities), within the framework of which the calculation methods were assessed, both previously used in aircraft construction and promising, as the initial ones, the conditions of real problems solved / unsolved during the Second World War were taken and the post-war time. Calculations for "combined power plants" showed that at that time only liquid rocket engines could realize a temporary increase in the speed of the screw engine (within 50-100 km / h) (based on the strength of materials of that time, the characteristics of technologies and the general proportions of the masses of individual An all-metal wing was an indispensable condition for overcoming the 0.7; 0,71M line. There was another problem of such machines, not described in the article - as a result of the appearance of an additional thrust vector, the centering of the aircraft changed dramatically worsening stability / controllability. Without going into the "jungle of theory "we can say that the simplest solution to the problems of the operating range of the At the same time, the level of the culture of operation of that time, combined with the aggressiveness of the components of the fuel mixture, made it highly desirable to perform the gas-dynamic installation in the form of a removable unit that combines liquid-propellant engine tanks and systems, allowing to repair, refuel and store such the unit separately from the aircraft, installing it just before the flight. I will note that such a scheme requires a certain margin of safety / mass from the structure to implement "modularity." Taking into account all of the above, it can be assumed that obtaining a truly "working" high-altitude interceptor was possible when it was created on based on Tu-2; Pe-2.A type machines, taking into account the specifics of high-altitude interception, required the creation of a special machine in the indicated MGH.
  5. Taoist
    Taoist 25 December 2013 14: 10
    A much more effective and promising scheme not associated with a significant increase in the "forehead" and the absence of restrictions on the speed of switching on was the use of VRDC (jet engines with a mechanical compressor drive)
    such a scheme was implemented for example on the I-250.

    But the rapid development and improvement of turbojet engines in general put an end to the development of such "hybrid" installations
    1. Argon
      Argon 25 December 2013 17: 16
      My friend, you are mistaken, this scheme is the most regressive, its appearance and development is embedded in the framework of the saying - "with a bad head, the legs always hurt" - and this "masterpiece" was brought to life by a lack of understanding of the theory of the operation of compressors, or rather diaphragms (separation of steps ) axial multistage compressors (the main cause of surge-fires, the first German engines) At that time, the issue was solved by using radial compressors, where the role of diaphragms was played by certain cavities where the flow was inhibited by the method of changing the direction of movement, although the gas expanded somewhat, worsening the efficiency of the stage. The disadvantage of this scheme was that when starting the reactive part, the power on the propeller was not enough (this was especially evident when climbing), and the jet thrust did not compensate for this loss. The reactive part worked only in combat mode and was generally ballast, kerosene was burning in the nozzle, and the internal combustion engine was gasoline, so two more fuels had to be transported. x speeds are largely determined by the wing drag, more than 60%. The frontal drag of the fuselage can be reduced to a value of less than 20% even with a star-shaped engine. By the way, it was this scheme that had speed limits on "launch" (not lower than a certain one). launch (in some way does not apply to the VRDK) of a high-altitude nature, since the "ignition" was chemical (by mixing the mixture with the catholyzer), they could not find the proportions of the masses of the components relative to the barometric pressure, so that the outbreak would not turn into an explosion. and Sukhoi P.O. his car was called Su-8 or Su-7 (I don't remember) and surpassed the I-250 (MiG-13) in maximum speed, it also did not go into production.
      1. Taoist
        Taoist 25 December 2013 23: 15
        What does the "division of stages" have to do with the compressor? And what does the great gas-dynamic stability of centrifugal compressors have to do with it (especially since this scheme also turned out to be a dead end)? These are all the problems of the then turbojet engines with their low thrust, small resource and problems with changing flight parameters. That is why the idea appeared to combine the used screw + PD ligament with a "jet booster". And the mechanical drive of the compressor, firstly, made it possible to reduce the dimensions of the engine, and secondly, not to be tied to the shape of the gas path. And the fuel in this case was the same - gasoline. Learn materiel pliz.
        "The power plant of the E-30-20 consisted of a VK-107R engine (reduction of 0,5) and an air-jet engine with a compressor. The maximum total power of the motor and the VRDK was 2560 hp. The propeller is a three-bladed AV-UP-60 with a diameter of 3,1 m. The duration of continuous operation of the VRDK was no more than 10 minutes, and only in the combat mode of the engine. Gasoline consumption was 1200 kg / h, and the specific fuel consumption per 1 kg of thrust was hour was 1,76 kg. " (C)
        Of all the "hybrid circuits", this one had the greatest "weight return"
        PURVRD are ineffective at low speeds and have a large forehead. The liquid propellant rocket engine required to carry an oxidizer reserve with it and had virtually no thrust control ...
        Just like any "hybrid circuit", it had drawbacks in the form of "dead mass" and the complexity of synchronizing the work of the control system. But this was the only "hybrid" scheme brought to mass production ...

        Later, the problem of a sharp increase in thrust, if necessary, was solved by the use of dumped powder boosters. Well, all the varieties of hybrids remained in the history of aviation as the very steps groping for the "torn road".
        1. Simple
          Simple 26 December 2013 14: 01
          Greetings to all.
          Add a little to the topic of discussion:

          Ryan FR-1 Fireball:
  6. xomaNN
    xomaNN 25 December 2013 16: 44
    Not all roads lead in the right direction wink But you still have to go forward
  7. alone
    alone 25 December 2013 19: 02
    As you can see, the road to jet aircraft was not smooth, but people stubbornly went to this and in the end achieved a result.