Experimental fighter with WFD La-138

2
The experiments with the installation of the WFD on piston fighters were begun in the prewar years. Designer Merkulov I.A. in 1939 at a meeting of Tech. The NKAP Council suggested using a ramjet engine in combination with its own VMG to increase the maximum speed of the aircraft. The work was carried out with the support of the director of the plant No. 1 NKAP Voronin P.A. (since 1940 - Deputy Commissar aviation industry). Merkulov’s first ramjet from the DM series (“additional engine”) appeared in August 1939. The diameter of the DM-1 engine was 240 millimeters. In December of that year, two DM-15 engines with a diameter of 2 millimeters were installed on the I-400 bis fighter. From December 1939 to May 1940, test pilots Loginov P.E., Davydov A.V. and Sopotsko N.A. made 54 flights on this machine. At its own speed of 315 km / h, accelerators gave the aircraft an increase of about 15 km / h. Flight tests in September 1940 passed the I-153 with a DM-2 installed on it (test pilots Loginov P.E., Davydov A.V. and Zhukov A.I.) The average speed increase after turning on the ramjet engine was 30 km / h . About a month later, the I-153 was tested, equipped with advanced DM-4 engines. On this plane, on October 27, at an altitude of 2 thousand meters, they gained an increase of 51 km / h. But the fuel consumption of ramjet engines was significantly greater than that of piston engines - in DM-4 it was 20 kg per minute.

People's Commissar Shahurin A.I. in January, 1941 reported in a letter addressed to Stalin: “The short-term use of an air-jet engine allows an aircraft to gain an advantage in combat at the expense of maximum speed. This makes it possible to overtake the enemy or, if necessary, escape from it. The high gas consumption of the WFD observed today does not allows you to talk about the direct use of this engine in combat aircraft.This requires the engine to be finalized, for which a special grill is organized at the Central Aerohydrodynamic Institute It is planned to organize an experimental base for jet engines and pressurized cabins in the industrial building of the former cloth factory, which currently occupies the home of disabled chronicles. near Moscow, near the station Vladykino.

Experimental fighter with WFD La-138
Fighter "126PVRD"


In 1940-1941, the installation of the WFD was performed on an experienced BoF-1 fighter (I-207 No. 3, designers Borovkov and Florov) and on the Yak-1. On the I-207 fighter, they made about 20 flights with the inclusion of a ramjet propulsion system (the DM-4 was installed). In parallel, these designers were developing a fighter with an M-71 engine and two DM-12 direct-flow jet engines. According to calculations, from the inclusion of accelerators, the speed increase reached from 100 to 150 km / h with the operating time of 20 minutes. Work on the Yak-1 aircraft with a ramjet engine, which was supposed to give a ten-minute speed increase in 100 km / h, was not developed. A year later, Yakovlev designed the Yak-7P fighter, equipped with one D-1A-1100 liquid-propellant rocket engine (developed by Dushkin LS) and two propellant DM-4, but failed to implement this project. In 1944, the DM-7с engines were installed on the Yak-4B piston fighter. Test pilot Anokhin S.N. made several flights on this plane, while the maximum speed increase when two ramjet engines were turned on at an altitude of 2340 m amounted to 53 km / h.

The greatest amount of work on the installation of the WFD on piston airplanes was made on SA Lavochkin fighters.

In August 1942 of the year, flight test LaGG-3 No.31213173 was carried out, equipped with two flow engines VRD-1 developed by the Research Institute of Civil Air Fleet and the Institute of Chemical Engineering (engine builder MM Bondaryuk was the head of the Research Institute of Civil Air Fleet at that time). The purpose of the test was to evaluate the performance and efficiency of the WFD-3, presented in two versions: normal (total length - 1 millimeters, diameter of the entrance - 2150 millimeters, weight - 140 kilograms) and forced (total length - 16 millimeters, diameter of the entrance - 1900 millimeters , weight - 170 kilogram). The engines were attached near the second rib to the planes of the aircraft. Fuel was supplied to the engines using the BNK-16 fuel pump mounted on the right-hand drive of the engine synchronizer. Air was drawn from the engine supercharger for partial evaporation and spraying of gasoline.

On the ground before the flight test was carried tatirovka fuel flow. Were conducted fire tests of the WFD-1, during which the velocity head was created LaGG-5, installed in front of the test aircraft. On the ground, the engine was able to start only twice, but because of the low speed and unevenness of the blowing flow, it was not possible to draw conclusions about the operation of the WFD-1 engine.

5 August the first flight of the LaGG-3. The main purpose of the test was to check the ramjet engine mount. During the next six flights, the fuel supply was completed, the ignition system and the mixture were adjusted, the launch and operation of the WFD-1 was checked at various speeds and altitudes. In seven flights, the efficiency and starting qualities of the engines were investigated, and the loss of maximum speed was determined in the absence and presence of suspension nodes fairings. Before 16 August, test pilot Captain Mischenko made flights on LaGG-3 equipped with WFD-1 14.

Fighter "126PVRD"


At an altitude of 1,5 thou. M, the absolute increase in the maximum speed (relative to the speed of an aircraft with a disabled ramjet engine) was equal to 12-15 km / h. The engines and fairings of the suspension assemblies had a large aerodynamic resistance, which reduced the maximum flight speed of 35-40 kilometers per hour. Despite the fact that in WFD-1 the combustion process was not regulated, the increase in speed obtained during the tests practically did not differ from the calculated value. According to the calculations carried out during the flight LaGG-3 No.31213173 with the M-105PF engine, the maximum speed from switching on the accelerators was to be 1,5 km / h at the height of 17 thousand meters, 4 km / h at the height of 23 for normal version and 40 and 49 km / h, respectively - for the forced. True, the forced version was not tested due to insufficient performance of the BHK-10 pump.

According to the results of flight tests, the following conclusion was made: "Work on launching at high altitudes, improving the combustion mode, automatically adjusting the composition of the fuel mixture and designing rational forms of the WFD and suspension, providing an organic connection with the aircraft, must be accelerated." Currently, the report on the first flight test of the LaGG-3 with the WFD-1 is stored in the scientific and technical library of the Keldysh Scientific Center.

Bondaryuk M.M. continued work on the creation of aircraft direct-flow engines. In 1944, a ramjet-430 was created with a diameter of 430 of millimeters and a weight at the ground of 170 kgf. In March, 1946, at plant number XXUMX, carried out the conceptual design of the SA Lavochkin prototype aircraft. "301", equipped with two such engines. But then the choice was stopped on the fighter "120" with four guns. This aircraft, modified by the installation of a pair of additional ramjet-126 engines, was assigned the factory index "430" (La-164 ramjet).

Near rib No. 2, four easily detachable attachment points for accelerators were mounted on both wing consoles, metal fairings were installed between the engine casing and the wing, and a pressure receiver above the ramjet 430. The elevator boom spar and stabilizer mountings are further strengthened. Inside the cockpit installed equipment associated with accelerators. In place of the 2-x guns, ammunition ammunition boxes installed power supply and ramjet system control units.

At the flight test station 301-th plant 26 June - 4 September 1946, joint factory tests of the aircraft "164" were held. The main goal was to obtain data to determine the performance and efficiency of accelerators. Test pilots of the plant Popov A.A. and Davydov A.V. 34 flight was performed (5 and 29, respectively) with a total duration of 20,5 hours at altitudes 200, 500, 1000, 2000, 3000 and 4800 m. During thirty flights, direct-flow air-jet engines were turned on, the total operating time in 46 air was min. Ignition failures occurred in accelerator 20 inclusions (from 110). The main cause of failures is a malfunction in the fuel injection and ignition systems. Only one failure occurred while both systems were operational. After analyzing the causes of failures, it turned out that they were either inflated by the fumes or the improper operation of the starting nozzle, caused by a violation of the throttle adjustment or clogging.

Fighter "138"


During the tests at altitude 2340 m with working ramjet, the maximum flight speed in 694 km / h was obtained, at the height 1235 meters - 663 km / h. The speed increase was equal to 109 and 104 kilometers per hour, respectively, which corresponded to the calculated data and indicated excellent engine performance. However, the accelerators had a large aerodynamic drag, leading to a deterioration in flight performance. The increase in speed relative to the aircraft, which does not have boosters, at the altitudes as a result was equal to 64 and 62 kilometers per hour. With spent fuel adjustments and improved suspension aerodynamics at fully steady speed, the increase in the speed of the 164 aircraft from 10 to 15 kilometers at 2 altitude thousandthousands of meters could be increased to 80 thousandth meters - 5 km / h

Piloting the experimental aircraft during takeoff, climb, and also on the horizons, in the opinion of AV Davydov, a leading test pilot, did not differ much from piloting Lavochkin's conventional serial fighters. The only exception was the take-off, which required a longer takeoff run (on 100-125 m) and lasted a little longer.

The use of a ramjet engine as an accelerator provided a number of advantages compared with a liquid rocket engine: less time to prepare the engines for flight, operation of the accelerators using the same fuel as the main engine, the absence of nitric acid on board, the ease of suspension of the accelerators, the ability to make multiple on / off in flight. In addition, it appeared that the ramjet-430 easy to operate and maintain the aerodrome.

According to the test results, it was recommended that after the elimination of the detected defects, it was established to install the engine of a ramjet 430 on the 130 aircraft, which has a larger fuel reserve and, after factory tests, present it to the state. tests. So, in the plans for the 1947 year appeared an experienced aircraft "138" (La 138). It was created on the basis of the La-9 fighter and equipped with two additional ramjet-430. The engines were mounted on three adjustable nodes under the wing.

With La-9, in connection with the installation of accelerators, the rightmost cannon and its power were removed, providing it with the equipment necessary for controlling and maintaining the ramjet engine.

In February, 1947, two aircraft "138" and "138D" passed factory tests. "138" th made all 20 flights, "138" - 38. Only in ten flights the task was fulfilled satisfactorily. The reason for the failure of the task in 19 cases was a failure in the additional engines. Their reliable work was ensured only at altitudes up to 3 thousand m, where the increase in maximum speed was approximately 60 km / h and an increase in the altitude of the VMG was observed.

Due to the low reliability of the ramjet 430, work on the "138" fighter was suspended, it was thought, until the delivery of finished engines, reliably operating in all speed ranges and working heights. But it turned out - for good.

In addition to the ramjet-430, the D-10 and D-13 PWRDs (pulsating air-jet engine), developed under the guidance of V.N. Chelomey, were installed on the Lavochkin piston airplanes, at the plant NKAP No. XXUMX. The work on equipping the La-51 fighter with two D-7 engines (thrust each 10 kgf) was completed in November 200. At the end of the summer of next year, flight tests of this machine were carried out. The aircraft was operated by the pilot of the plant No. XXUMX N. Gavrilov. The test results not only confirmed the calculated data, but also surpassed them. The operating HRVD at an altitude of 1945 thousandth m increased the speed of flight La-51 at 3 km / h, which exceeded the calculated value by 7 km / h. During the flight at an altitude of 119 m with a motor throttled to 29 millimeters of mercury, the speed increased by 800 km / h. But due to the fact that the maximum speed with operating accelerators was limited to 600 kilometers per hour, the F-D-193 was not working in the optimal thrust mode, and it was not possible to get a full speed increase when the engines were turned on. October 630 10 (after one year of operation) the aircraft was not allowed to fly on the basis of the repair bulletin. For further testing, it was recommended to use the all-metal La 15 aircraft. By order of Khrunichev, the D-1946 engines installed the UTI-La-9 fighter on the 10 in the same year to participate in the May 3 parade. Both engines and airplanes passed flight tests, but they did not participate in the parade.

The PWRD D-10 in the Chelomey design bureau were modified into the D-13 engine intended for the La-9. The engine received a more perfect form, the design of valve boxes and diffusers was improved. Fuel for D-13, served under great pressure, was the same as for the engine ASH-82FN. Plant No.51 28 of May 1947 of the year was given a task to install the D-13 engines on the 12 La-9 production fighters. These aircraft were intended to participate in the parade dedicated to the Day of Aviation.

In July X-NUMX, the D-1947 passed factory bench tests. The engine was installed on the serial La-13, created by plant No. 9, for which the wing ribs, to which the engine mount beam was attached, and the mounting of the horizontal tail ends, were strengthened at the 21 plant. A more robust rear tie-down band of the engine hood with its additional attachment and a new elevator trimmer were installed. Fuel system La-51 was modified with the installation of two Pulsejet. Leaving two guns instead of four, thereby lowering the flight mass, removed all the armor support and ammunition, to shift the center forward on the gear housing, they fixed the 9-kilogram load. In the cockpit mounted additional devices.

The factory tests of the La-9 fighter with the PU-VRD D-13 began in August 1947. The main focus of the tests was on the engines - the reliability of the launch and operation in all modes were checked. 30 August 1947 this aircraft and twelve more La-9 with D-13 at an altitude of 100 meters flew over the Tushino airfield. Pilot test pilots of the State Red Banner Scientific Research Institute of the Air Force were awarded orders of the USSR.

In November 1947, factory tests were interrupted and the La-9 fighter, equipped with the D-13 engine, was transferred to the Research Institute of the Air Force where it conducted special flight tests to determine the increase in the horizontal speed due to the inclusion of two IDFDs.

The lack of knowledge of the engines, as well as the need to ensure the durability of the aircraft led to restrictions in flight altitude and speed La-9 with PvRD. In this regard, the determination of the horizontal maximum speed was carried out with the engine hoods fully open on the side flaps, which affected only the absolute values ​​of the horizontal speed and made it possible to determine their gain due to accelerators.

Between 21.11.1947 and 13.01.1948, ten flights of La-9 fighters were made. The total duration of the flight hours 4. 11 minutes. Each D-13 engine has run 27 minutes.

Special flight tests showed far from excellent results. The increase in the maximum horizontal speed of the La-9 fighter due to the D-13 engine's operation, although it was 127 kilometers per hour, but when compared with the speed of this aircraft without IDRD, it was only 70 kilometers per hour. The maximum horizontal speed due to the installation of the D-13 engine decreased by 42 kilometer per hour and another 15 "gave" the beams of outboard engines and fairings. As a result, the total reduction in speed was 57 kilometers per hour. Thus, the increase in speed was not much greater than on an airplane with a ramjet engine. There was no need to expect anything else: after all, at a speed of M = 0,4-0,5 (about 490-610 kilometers per hour from the ground), because of a much smaller air flow, the pulsating jet engine begins to yield to the direct-flow engine.

Pulsating engines in terms of vibrations and noise exceeded all other air-jet engines. In the book "The Front Goes Through the KB" Arlazorova MS Krivyakin VA’s memoirs are cited: “These were surprisingly loud engines. I simply didn’t hear such hellish noise. When machines with pulsating engines passed over the plant’s territory in preparation for the parade, it might have seemed that the light show began ...”. At the same time, the Germans, who were pioneers in the field of combat use of aircraft with similar engines, suffered for a long time with the effects of vibrations on R-103 (V-1) RC devices, which often led to their failure. Experienced Me-328 on its first flight in June, 1944, collapsed due to the impact of strong vibrations caused by the operation of the pulsating jet engine As-014. Strong noise and significant vibrations contributed to pilot fatigue. The piloting technique of the La-9 fighter equipped with the HRVD somewhat deteriorated compared to the serial La-9: the takeoff run increased and the necessary speed was required to transfer the fighter to its climb longer to reach the ground; The La-9, equipped with a PWRD, was losing speed faster on vertical figures; horizontal figures performed sluggishly. Both tests, as a rule, did not turn on both D-13 simultaneously, and one of them was often arbitrarily turned off. These shortcomings with a small increase in the horizontal maximum speed, as well as the high fuel consumption of 470 kg / t, made it possible to conclude that the D-13 engine on the La-9 fighter jets is inappropriate.

Experiments with the installation of accelerators with a PWRM, ramjet and ramjet engine and piston rocket engine on piston fighters showed that these additional jet engines do not allow to bring the speed of the aircraft to the values ​​corresponding to new developments in aviation. In most cases, the accelerators became an additional source of trouble, more than overlapping the short-term and small increase in maximum speed. The only way out of this situation is to create an airplane with a turbojet engine.

Flight technical characteristics of experimental fighters La-126PVRD / La-138:
Wingspan - 9,80 m / 9,80 m;
Length - 8,64 m / 8,64 m;
Height - 3,56 m / 3,56 m;
Wing area - 17,59 m2 / 17,59 m2;
Empty aircraft weight - 2710 kg / 3104 kg;
Takeoff weight of the aircraft - 3300 kg / 3771 kg;
Engine type - PDAH-82FN and 2 VRD-430 / PDAH-82FN and 2 ВРД-430;
Power - 1850 HP / 1850 HP;
Maximum speed at the ground - 660 km / h;
Maximum speed at height - 692 km / h / 760 km / h;
Practical range - 1250 km;
Crew - 1 man;
Armament - three guns caliber 23 mm.
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    1. +3
      4 October 2012 15: 03
      There was another shop but already completely with the WFD

      La-WFD, since May 1944 it was designed at the Lavochkina Design Bureau and was supposed to go on flight tests in March 1946. but circumstances found the engine, and the car was better
    2. +2
      4 October 2012 16: 01
      Then we had trouble with the engines all the way, for which they later made up, the Chinese still cannot repeat.

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