Aviation of World War II
By 1939, the Soviet experimental aircraft industry found itself in a situation close to a crisis. The disorganizing role of the repressions that hit the industry in 1937-1938 affected. In addition, a qualitatively new level of technology required new technologies and materials, a new organization of production and wider experimental development. In the field of technology and aviation materials, the Soviet Union was still lagging behind the advanced countries, which had a particularly strong effect on engine building, since the path of licensed production and subsequent improvement of the best foreign engines, which is very common throughout the world, was already excluded due to the sharply aggravated international situation. In addition, the leading aviation research center is TsAGI. created back in the 1920s in Moscow could no longer fully provide designers with experimental material. The new TsAGI, with its unique wind tunnels and strength test benches, was still under construction. It was ready only by 1939-1940.
By 1939, the lagging behind of Soviet aviation became obvious. It consisted not so much in the absence of new aircraft in the Air Force, but in the fact that such aircraft, with a few exceptions, were not even developed and tested. In the first half of 1939, the country's leadership held two extensive meetings with the involvement of employees of the People's Commissariat of the aviation industry, scientific institutes, pilots and military specialists. As a result, a set of measures was developed for the speedy elimination of the backlog in the field of aviation. One such event was the organization of a number of new design offices. An extremely intense, one might even say emergency, work began on the creation of a new generation of Soviet aircraft.
One of the first successful new aircraft was the fighter A.S. Yakovlev I-26. It entered testing in January 1940. The aircraft was a cantilever monoplane of mixed design, well adapted to mass production conditions. Liquid cooling motor M-105P. The armament consisted of one 20 mm ShVAK cannon, which fired through the hollow shaft of the propeller gearbox, and two ShKAS 7.62 mm synchronous rapid-fire machine guns. A distinctive feature of this aircraft, as well as other combat aircraft of A.S. Yakovlev during the war, was its low weight, good stability and ease of piloting. After testing and the necessary improvements, the I-26 was launched into a series and was soon given the Yak-1 brand. In the first half of the Great Patriotic War, this aircraft became one of the main new Soviet fighters, and in just 1940-1944. 8720 aircraft of this type were produced.
In the first year and a half of the war, the Yak-1 was the best Soviet fighter. It harmoniously combined high flight characteristics and armament. Compared to the main fighter of Nazi Germany, the Messerschmitt Bf-109E, the Yak-1 had superiority in speed and all types of maneuver. However, with the advent of the more advanced Bf-109F, the flight data of the Yak-1 became insufficient. Then, at the initiative of A.S. Yakovlev Design Bureau and the Air Force Research Institute, a modification of the motor was carried out, due to which at low altitudes, i.e. just where air battles were mainly fought, the engine power increased significantly. The Yak-1 fighter with a new boosted engine, designated M-105PF, has been mass-produced since the summer of 1942. In terms of speed at low and medium altitudes, this aircraft was not inferior to the main German Bf-109F and G fighters, surpassed them in maneuverability, but was slightly inferior in climb.
Armament. One 20-mm ShVAK cannon with 220 rounds of ammunition, 2 ShKAS 7.62-mm machine guns with 1,500 rounds of ammunition.
In the course of mass production, the Yak-1 was repeatedly modified. Simultaneously with the change of the engine, the armament was also changed: instead of two ShKAS, a much more effective heavy-caliber (12.7 mm) UB machine gun was installed. Then they improved aerodynamics, installed a radio and improved the view of the upper hemisphere from the cockpit. All ongoing activities made it possible to continuously maintain the high combat qualities of the Yak-1, and this fighter was in service with the Soviet Air Force until the end of the war.
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* Forcing of the engine during 10 minutes.
** On speed making 90 % from maximal.
Issues related to the winter operation of the aircraft were basically resolved in the winter of 1940-1941. On January 14, 1941, by order of the People's Commissar of the Aviation Industry, all Yak-1s from January 20 were produced with insulated water and oil systems. By the same order, on an experimental basis, at plant No. 301, additional shunt lines and pressure reducing valves were installed and tested in the oil system, which made it possible to start the engine even with a completely frozen oil cooler. But the lack of a ski chassis limited the use of the Yak-1 from field airfields, which were not cleared of snow in winter.
Equipping the Yak-1 with a ski chassis was technically very difficult, because the skis had to be retracted in flight. However, according to wartime norms, only two weeks were allotted to solve this problem. By order of the People's Commissar of August 13, 1941, the designers of new serial aircraft had to submit for approval to the Deputy People's Commissar P.V. Dementyev, A.S. Yakovlev, P.A. September, to make samples of winter skis, check them with static tests and blowing in a wind tunnel. And, in pursuit, by order issued on August 15, 1941, it was ordered to unify the skis on the skid, cardan and shock absorber for the MiG-3, Yak-1, Yak-7, LaGG-3 fighters. The design bureau, headed by A.S. Yakovlev, was not taken by surprise by these orders. Firstly, the I-26-I has already been operated on skis, though not retractable. And secondly, the Chief Designer of the Design Bureau, being far from the last figure in the People's Commissariat, felt in advance all the new trends, ideas, proposals and could react to them ahead of events. Therefore, already on August 15 (just two days after the appearance of the order), full-scale tests of the Yak-1 with a ski chassis began in the TsAGI T-101 wind tunnel. These tests, which ended on August 28, 1941, showed that with the optimal shape of the skis, a decrease in maximum speed of about 12 km / h can be expected. At the same time, the flight weight increased, as a result of which, in terms of characteristics, our aircraft became somewhat inferior to the aircraft of other countries, which flew all year with a wheeled landing gear and therefore had no loss in speed and maneuverability.
Nevertheless, on the basis of research at TsAGI, the optimal form of skis, from the point of view of both aerodynamics and production, was selected, and, according to the order of the People's Commissar of November 4, 1941, factory No. manufacturing.
According to the decision of the GKO, the NKAP was obliged to design, manufacture and submit to the Air Force a retractable type of skis unified in skid, cardan and shock absorber for the MiG-3, Yak-1, Yak-7 and LaGG-3 aircraft within two weeks. (For the first time in the Yak-1 family, skis were used during the first period of factory testing of the I-26-1 in early 1940).
The drawings of skis for serial aircraft Yak-1 and Yak-7 were made by A.S. Yakovlev Design Bureau and transferred to serial factories. The ski is two-spar, 620 mm wide and 1650 mm long. The total area of the two main skis is 2.04 mg. The tail ski is retractable, its design is common to all fighters. The masses of the two main skis are 123 kg, the tail ski is 6 kg.
The experience of using the Yak-1, Yak-7, LaGG-3 and MiG-3 showed that the installation of skis on our aircraft put them at a disadvantage in relation to enemy aircraft that flew all year round with wheels and therefore had no losses speed.
As expected, the performance of the machine with the ski chassis has deteriorated. During control tests conducted at the Research Institute of the Air Force KA from March 7 to April 2, 1942, the Yak-1 aircraft serial number 3855 with skis reached a speed of 532 km / h, which was 27 km / h less than that of the previous control tests of the same type of production aircraft with a wheeled landing gear.
This was due mainly to an increase in aerodynamic drag due to the loose fit of the skis to the wing and an increase in the flight weight of the aircraft. An increase in the length of the run and a decrease in the length of the run were the result of a higher friction coefficient of skis on snow than wheels on the ground.
The winter chalky coloration increased the surface roughness and, as a result, also reduced the maximum speed by 7...10 km/h and somewhat worsened other flight characteristics. However, when cleaning ("sanding") the surface of the aircraft, its resistance became almost the same as before applying the winter coloring.
In terms of piloting technique, the Yak-1 with a ski chassis and winter coloring basically did not differ from the Yak-1 with a wheeled chassis. As for landing, it has become even easier, because in case of errors (for example, landing with a roll on skis), the plane almost did not "goat", as in the case of a wheeled landing gear. In addition, the anti-bonnet angle has increased by at least 3° and was 28.5°. Therefore, the danger of the aircraft nosed over on the run, despite stronger braking, was almost completely excluded.
Problems arose during the operation of skis in parts. According to B.N. Eremin, the squadron commander of the 296th IAP, and later the commander of the 31st IAP, "sometimes in battle, from the sharp evolution of the machine, the skis came off the locks and the plane was thrown, which made it almost uncontrollable. The technicians had a lot of trouble , because when landing, the brackets on which the skis were attached quickly failed. At night, in severe frosts, in the absence of spare parts and tools, the technicians removed the skis, welded cracks in the bushings of the boars of the skis. However, this did not guarantee proper operation, and after the first landing, cracks could appear in them again. Partly here was the fault of the plant. Limited by time, he was forced to finish the ski chassis in the course of production. By the time the causes of the cracks in the boar were identified and the kinematics of the ski chassis were worked out, 581 sets had already been produced with numerous differences from each other.
By the winter of 1942-1943. at plant number 292, a new ski chassis with a boar designed by Zhokhov was tested. But taught by the bitter experience of using fighters on skis, which significantly worsened their combat qualities, the Air Force command decided to remove the skis and roll the airfields in winter.
In total, from September 1941 to February 25, 1942, about 830 Yak-1 aircraft were produced on skis. After that, skis were used only in some northern sectors of the front.
The abandonment of skis required the clearing of airfields from snow, which we had not done before. This placed on the BAO (airfield service battalions) an additional greater responsibility for preparing field airfields for flights, required the development of special clearing tools ("smokers" of scrapers, snow plows), but it allowed the aircraft to have their inherent flight characteristics.
Trying to meet the conflicting requirements of the Air Force (to ensure the take-off of fighters in winter from uncleared airfields without deteriorating flight data), the pilot of the Research Institute of the Civil Air Fleet B.K. Kondratiev at the end of 1941 proposed the idea of "take-off skis" dropped after takeoff and takeoff. This made it possible to fly from unprepared airfields with any snow cover. Landing was carried out with a conventional wheeled chassis, which made it possible to land on snow with a depth, as it turned out during tests, half the diameter of the wheel.
Ordinary skis were converted into take-off skis. They were equipped with a special nest from the front and side plank walls designed by pilot engineer A.M. Teteryukov. The reset was carried out very simply: as the wheels came off, they went up from the sockets and the skis remained on the snow.
With the abandonment of the ski landing gear on Air Force aircraft, the importance of take-off skis decreased, but they were indispensable in the evacuation of an aircraft that had made an emergency landing on snow.
The Yak-1b became the quintessence of all work to improve the Yak-1 in 1942. They began at TsAGI, where from May 24 to June 10, 1942, research was conducted to find ways to improve the efficiency of water and oil coolers, and from July 26, 1942 - in order to develop measures to increase the maximum speed. Lead research engineer - AI Silman (lead engineer for the Yak-1 of the 1st laboratory of TsAGI). These works have shown that it is possible to increase the maximum speed by 25-28 km/h by means of sufficiently simple and affordable means for mass production (sealing and changing the shape of oil and water cooler tunnels, improving the shape of the intake and exhaust pipes, sealing the fuselage), and if cleaning tail support and full closure of the landing gear domes, then - at 33-38 km / h.
On the recommendations of TsAGI, the NKAP was re-equipped at the LII and in August-September 1942 it passed flight tests of the Yak-1 No. 0868 with M-105PF motor. The following changes have been made to its design in order to improve the operation of the water and oil cooling systems and increase the maximum speed.
1. For the water radiator:
changed the profile of the upper front wall of the entrance of the tunnel;
increased stroke of the control damper by 50 mm (up to 350 mm);
The tunnel has been sealed.
2. By oil cooler:
the area of the entrance part of the tunnel is reduced by 40% and the tunnel itself is extended to 225 mm;
the exit part of the tunnel has been extended to 410 mm, and the profile of its upper wall has been made smoother;
increased stroke of the regulating damper by 80 mm (up to 340 mm);
The tunnel has been sealed.
3. Changed the shape of the section and the location of the suction pipe of the supercharger.
4. Fairings were installed on the exhaust pipes, on the outlet of the crankcase purge pipe and aileron control brackets.
5. Installed fairing-visor on the sliding part of the canopy.
6. The fuselage was sealed (the fireproof partition was sealed, a plywood partition behind the armored back and a cloth one behind the water radiator were installed).
7. The fairing of the inlet of the machine gun casings was installed and the nozzles for the removal of powder gases were sealed.
8. Changed the pairing of the tail unit with the fuselage.
9. Reduced to 6-7 mm gap between the wing and the ailerons.
According to the test results, the changes made to the design gave an increase in speed by 23 km / h (for the car No. 0868 at an altitude of 3500 m, the speed became 594 km / h, and for the serial Yak-1 at an altitude of 3650 m - 571 km / h ). The rate of climb remained unchanged. The increase in speed could be considered guaranteed, since the tests of the Yak-1 No. 0868 entered after operation in part, i.e. with a full range of resulting deterioration in aerodynamic shapes: paintwork damage, dents in metal parts, poor fit of hatches and fairings.
The tactical qualities of the Yak-1 have increased so much that A.S. Yakovlev On July 1, 1942, turned to the people's commissar of the aviation industry with a request to issue a military series of 20 aircraft with similar changes and send them to the front for testing in combat conditions.
The advantages were so obvious that the military series was not built. By a GKO resolution of August 11, 1942, an order was given to the director of the plant No. 292 on the introduction of a series of changes tested on the Yak-1 No. 3560. In addition, the decree provided for the installation on modified "yaks" of an oil cooler of the Yak-7 type, a VISH-105 propeller, a suction pipe of a supercharger with a dust filter designed by TsAGI and a retractable tail support. The following deadlines were set: to produce the first 10 vehicles in September, 100 vehicles in October, and from November to produce only new Yak-1s (later, by order of the People's Commissar of the Aviation Industry dated October 2, 1942, a full transition to the production of "yaks" with improved visibility was ordered to begin from 10 October).
The plant coped with the task. The number of Yak-1 b stipulated by the decree left the factory shops within the specified time. For some reason, the name of the new modification did not take root, although it was used everywhere. The name Yak-1SB appeared as a result of a mistake by the military representative of the UVVS of the Navy, who added the open name of the SB vehicle used at the plant to the secret name. All innovations were introduced into production gradually, so as not to reduce the production of aircraft. So, the retractable tail support began to be installed on the Yak-1 from the 87th series, from the 89th series an oil deflector appeared, which reduced the splashing of the cockpit lantern with oil, new lantern and weapons appeared from the 99th series. Since the tests of the measures proposed by TsAGI to improve aerodynamics were completed by September 11, their introduction into the series was also delayed, it began on November 15, 1942, and was also carried out gradually. The whole process was completed by about the 110th episode.
At the same time, measures were taken to partially lighten the design of serial aircraft. By order of the State Defense Committee of September 22, 1942, the following were removed from the Yak-1: a headlight with a fuse and a mains switch, a light signaling the released position of the tail support, shielding of the electrical network after detachable boxes, clock heating wiring, a plug socket for the tail air navigation light (ANO), automatic pressure , weapon pressure gauge, MP-20 pneumatic reloading device, RPK-10 radio semi-compass, variometer, foot control cable-understudy, limit switch on the gas sector. The same decree ordered that night lighting equipment, a headlight, a variometer and RPK-10 be installed on aircraft only by special order for air defense aircraft. The improvement of the tactical properties of the aircraft was facilitated by the installation of the RSI-4 radio receiver on all Yak-1s from August 20, 1942, and the RSI-3 radio transmitter on every fifth (from October 1 on every even numbered one).
Therefore, the Yak-1b confidently led the comparative control tests conducted at the plant No. 292 brigade LII NKAP together with the flight test group of the plant. The Yak-1b with improved aerodynamics and standard armament was inferior to the light version only in vertical maneuver and was in every respect better than the serial Yak-1.
Serial production of the Yak-1B began in September 1942 in accordance with the GKO decree of August 11, 1942. In September, 10 aircraft were produced, and from October only Yak-1B aircraft were produced. A total of 4188 were built. From December 10, 1942 to January 28, 1943, Yak-1B aircraft underwent military tests for combat use in 32 Guards. IAP 210 IAD 3 VA (Kalinin Front) and 176 IAP 283 IAD 16 VA (Stalingrad Front).
During the military tests on 58 aircraft, 669 sorties were made with a raid of 6174, 38 air battles were conducted, as a result of which 25 enemy aircraft were shot down, including: Me-109F - 5, Ju-87 - 8, He- 111 - 3, Hs-126 - 2, FW-190 - 6, Ju-88 - 1. Own losses: 6 Yak-1B.
The new fire control system and the cockpit with improved visibility to the rear hemisphere were highly appreciated by the flight crew and were accepted for installation on all fighter-type aircraft. Other changes made by the OKB were also approved. It should be noted that back in 1940, Yu.B. -mm guns of B.G. Shpitalny. The check showed that the 37 mm cannon could not be installed on the Yak-1, because its installation would require a change in the layout of the cockpit and lengthening the fuselage.
In November 1942, TsAGI developed another version of the oil cooler shape and tested it in the T-104 wind tunnel on a full-scale model. The use of such an oil cooler would increase the maximum speed by 6-8 km/h. In July 1943, it was introduced into the series, and after that, the issues of improving the aerodynamics of the Yak-1 did not return.
Comparative Analysis of Designs and FTD of Soviet and German Fighters that Took Part in the WWII
Flight Technical Data - FTD
The first of the new generation fighters in January 1940 was the aircraft of the aircraft designer A.S. Yakovlev I-26, later renamed Yak-1. It had a mixed design, in which wood and metal were approximately equally represented. The wing is all-wood, one-piece, with a pine spar and a working plywood sheathing. The fuselage frame is a welded square-section truss made of thin-walled steel pipes with internal cross braces, which was integral with the motor. Above and below the cab, the frame was profiled with plywood gargrottoes to give it a streamlined shape. The sides of the fuselage are sheathed with canvas. The stabilizer and keel, as well as the wing, had a wooden power set and plywood sheathing. Only the rudders and aileron frames (sheathing - canvas), removable engine hoods, a water radiator tunnel, wing and tail fairings, hatch covers, landing flaps, as well as flaps covering the landing gear struts in the retracted position were made of duralumin.
For its time, the design of the machine was very archaic and generally corresponded to the structural and power scheme developed by the German aircraft designer Anthony Fokker during the First World War. The same tubular fuselage brace with plywood and linen sheathing and a relatively thick solid wood cantilever wing.
Initially, the I-26 was designed for the 1250-horsepower M-106 engine, but engine builders did not manage to bring it to the required degree of reliability. Yakovlev had to install on the prototype of his fighter a less powerful, but more reliable and proven M-105P engine, which developed 1110 hp. with. at an altitude of 2000 meters and 1050 liters. with. - 4000 meters. The first production copies of the Yak-1 were equipped with the same engine (or M-105PA of the same power).
Of the positive qualities of the Yak-1, which favorably distinguished it from the I-16, in addition to a significant increase in flight data, it is necessary to note good stability, ease and simplicity of piloting, which made the aircraft affordable even for low-skilled pilots. Yakovlev managed to find a balance between maneuverability, stability and controllability; it was not for nothing that before the war he specialized mainly in training and sports cars. In addition, takeoff and landing on the "yak" were easier and safer than on the "donkey" and on the "instant".
The Yak-1 of the 1941 model had a takeoff weight of 2950 kg (without a radio station and equipment for night flights - about 2900 kg). The specific load on the power was 2.73 kg / hp, and on the bearing surface area - 171 kg / m². Thus, even without radio communications, the aircraft turned out to be noticeably heavier than the Bf 109E and F, lagging behind them in terms of power-to-weight ratio due to the greater weight and less powerful engine. As a result, the Yak-1 was inferior to the Messerschmitts in climb rate at the entire altitude range, and to the more aerodynamic Bf 109F in speed, although not as fatally as the I-16. Such was the inevitable price to be paid for simplicity and cheapness.
Despite the fact that the yak's turn time is about the same as that of the Messer, maneuverable combat for its pilot was still more difficult and required increased attention. The fact is that the Bf 109, due to the automatic slats, had a lower stall speed, it was more stable on steep turns and vertical aerobatics.
Lagging LTD shortcomings of the early "yak" were not limited to. The first serial aircraft, which entered the aviation unit in 1941, were still very "raw", unfinished and suffered from many "childhood diseases". Here is a list of design and manufacturing defects of serial Yak-1 fighters of the 1941 model, taken from the book of design engineer A.T. Stepants "Yak Fighters" (Moscow, "Mashinostroenie", 1992):
- overheating of water and oil when the engine is running at rated power;
- knocking out oil from the prompter, gearbox shaft seals and other engine seals (in flight, oil splashed the entire fuselage up to the tail unit);
- uneven and incomplete production of fuel from the right and left groups of wing gas tanks;
- cracks on the intake and exhaust pipes;
- compressed air leaks from the pneumatic system;
- skew and jamming of the cartridge belt of the right machine gun;
- frequent burnout of signal lamps;
- spontaneous (vibration) unscrewing of bolts and screws.
Let's dwell on the first point. In practice, it meant that due to the poor performance of the cooling system, the pilot periodically had to dump the gas in flight and give the engine a "respite" for several minutes, completely opening the radiator flap, otherwise the engine could overheat and jam at any time. It is not necessary to say what this threatened in aerial combat.
But in the course of serial production, the design flaws of the Yak-1 were gradually eliminated, the aircraft as a whole and its individual units became more reliable and trouble-free, although some defects, for example, the ejection of oil from the gearbox shaft seal, poisoned the lives of pilots and mechanics for a long time. On the hoods of individual cars, it was even necessary to install self-made guards or visors, as on the MiG-3, so that oil splashes did not fall on the glass of the cabins, impairing visibility.
The situation with radio communications on the Yak-1 was at first even worse than on the I-16. The first 1000 examples of the fighter had no radio stations at all. Only from the spring of 1942 the installation of radio equipment became more or less common, and from August it became mandatory. At the same time, at the beginning, only every tenth car had transmitters, from August 42nd - every fifth, and from October - every fourth. On the rest, only receivers were installed.
The armament of the Yak-1 is similar to the Messerschmitt Bf 109F - one 20-mm motor-gun ShVAK (ammunition - 120 rounds) and two synchronous ShKAS machine guns above the engine (750 rounds for each). The mass of a second salvo (1.99 kg) - due to the higher rate of fire of Soviet weapons, exceeded that of a German fighter.
By the beginning of the war, the Soviet aviation industry produced 425 Yak-1 fighters. 125 vehicles managed to enter the air regiments of the western border military districts, 92 of them were in combat readiness, but almost all of them were lost in the first days of the fighting. Until the end of 1941, another 856 Yak-1s were built.