Aviation of World War II
The Yak-9D with the M-105PF engine was a version of the usual serial "nine" with an increased fuel supply. All Yakovlev Design Bureau fighters had less time in the air after full refueling than the Messerschmitts, despite the fact that they were lighter than their opponents. And since in 1943 the Soviet troops went on the offensive, the task of covering operational breakthroughs from the air urgently required a greater range of fighters. The Yak-9D had two root gas tanks of 208 liters and two console tanks of 117 liters each. Thus, the capacity of the gas tanks was increased to 650 liters (480 kg) versus 440 liters (320 kg) for the Yak-9 with the M-105PF engine. The capacity of the oil tank was also increased to 48 kg, instead of 25 kg for its predecessor. Recall that on the Bf-109G, namely these fighters were the most massive in the Luftwaffe, the problem of increasing the range was solved differently. Each German fighter could carry one standard external tank with a capacity of 300 liters. With this tank, the range reached 620 miles (i.e. about 1200 km). And when entering into battle, the tank was simply dropped and the fighter became as maneuverable and fast as usual. The tank was suspended under the center section near the center of mass and had a streamlined teardrop shape. On Yak-9 aircraft of the military series, fuel was supplied to the engine from a supply tank with a capacity of 6 liters, and all gas tanks were connected to it independently. But a greater number of tanks and individual fuel lines increased the fire hazard. Check valves were installed in the fuel overflow lines from one tank to another. Trying to at least compensate for the shortcomings of these innovations, the design bureau specialists increased armor protection by 16 kg, the flight weight of the aircraft increased to 3117 kg, for comparison, the BM09G-2 of 1942 had a flight weight of 3050 kg **. However, it was with him that the workers of the Yakovlevsky Design Bureau liked to compare their products of 1943, lighter, but made mostly of wood. A BM09G-6 produced in 1943-1944, however, had a slightly larger flight weight of 3150 kg, but at the same time not only an all-metal structure and armor, and therefore greater survivability, but also much stronger weapons. Since 1943, the installation of two MG-131 heavy machine guns with 600 rounds of ammunition (300 per barrel) has become standard on German fighters, and the gun could be either a 20-mm MG-151 with 150 rounds, or a 30-mm Mk-103 with 60 rounds. shells. However, it only makes sense to compare the later version of the G-6 with the Mk-103 with the Yak-9T or K. Unlike the NS-37 and NS-45, the German cannon allowed firing continuously until the ammunition was completely used up. Well, the Yak-9D in the series had the same 20-mm ShVAK with 120 rounds of ammunition and one (left) synchronous UBS with 200 rounds. The maximum flight range of the fighter was significantly increased. The plane could fly in a straight line up to 1360 km. However, on fighters of the early series, long-range flights, especially in bad weather conditions, became simply dangerous. Aeronautical equipment was very modest, radio compasses on the Yak-9 began to be installed much later, long-range flights were not included in the training of fighter pilots of the Red Army Air Force. In addition, after flying 69 km, the fighter stopped “hearing the ground”, and therefore receiving information. Therefore, with sufficiently long flights (even 300-400 km), the leadership of groups by bombers, attack aircraft or transport vehicles was often used. Let's not forget that pilots in 1943 were still trained according to the super-accelerated program. According to combat units, the maximum range of the Yak-9D was 211 km, the maximum flight duration was 1 hour. 20 minutes, and the average reached only 54 minutes. at an average flow rate of 270 l/h. Therefore, there was no point in fully refueling, because. usually only about 40% of the fuel was consumed.
In the Normandy Air Regiment, one of the most productive regiments in the Soviet Air Force, console gas tanks were drowned out on their own initiative, and all flights were carried out with refueling only root tanks, which significantly improved the aircraft's centering and increased safety. This experience of the French was also adopted in other Soviet flying units. In air combat, the Yak-9D had a slight advantage over the Bf-109G-2 and FW-190A-8 in turns up to altitudes of 3500 m, and when half the fuel was used up, it was possible to fight in a vertical maneuver.
The experience of combat use of the Yak-9D together with the conventional Yak-9 and Yak-9T was not in favor of the former. Therefore, it was considered expedient to use the Yak-9D to perform special tasks that could not be solved by conventional Soviet fighters due to the small amount of fuel: escorting bombers deep behind enemy lines, ensuring a breakthrough for tank groups, for example, protecting them from destruction by specialized tank destroyers Ju -87G and Hs-129. It was also recommended to use the Yak-9D for "deep raids" and reconnaissance. The Yak-9D was one of the main series, although it was not always used with a full refueling. These aircraft were built from March 1943 to June 1946 3058 units. (according to English data - more than 3800 units), although by 1945 it was inferior in its main characteristics (especially in armament) to most enemy fighters and similar allied aircraft.
It should be noted that the serial production of wartime Soviet aircraft factories, for obvious reasons (low-skilled labor, etc.), differed significantly in quality from the standards. The performance characteristics of production aircraft were worse, and the resource was shorter. The attention of the leadership of the Yakovlevsky aircraft factories, including the Yakovlevsky Design Bureau, was repeatedly drawn to this. The German devices, right up to the very end of the war, corresponded much more precisely to the accepted standards, and their characteristics, especially of new machines, were very close to the standard.
In 1943, in addition to the development of aircraft produced in large series, the Yakovlev Design Bureau made a number of attempts to improve the aircraft, which nevertheless did not receive further development. It should also be mentioned here that A. Yakovlev, being more than all aircraft designers close to the person of the leader, had the opportunity to respond in a timely manner to the desires of the latter. And although Stalin largely lost faith in the power of his fighter aircraft, he nevertheless kept the development of new aircraft under control, within his personal, and now also Yakovlev's competence.
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Yak-9B (Bomber) with the VK-105PF engine was a fighter-bomber and was a modification of the serial Yak-9D N14-20. Factory index Yak-9L.
The modification consisted in the fact that behind the cockpit between the 2nd and 4th fuselage frames (in place of the rear cockpit) four bomb bays were equipped, arranged in pairs one after the other (in the form of pipes) for hanging four high-explosive bombs FAB- 100 or four cassettes with PTAB anti-tank bombs weighing 1.5 kg, 32 bombs in each cassette. Small arms like the Yak-9D.
Bomb bays have significantly expanded the range of combat use of the aircraft. Without bombs, the Yak-9B could be used as a front-line fighter, and with bombs - as a high-speed fighter-bomber to attack pinpoint, well-protected targets.
The walls of the compartments were tilted back at an angle of 75° to the longitudinal axis of the aircraft. From below, each compartment was closed by a separate sash. The bombs were hung in the compartments with stabilizers down and kept from falling out by doors, which, in turn, were held by locks. Adjustable stops were installed in the upper part of the compartments, centering the FAB-100 bombs.
Bombs could be dropped in pairs or in one gulp by opening the shutters with the help of electric triggers, activated by a button on the aircraft control stick, or with the help of an emergency mechanical ejector.
The order of dropping bombs was set by four toggle switches on the left side of the cockpit. For access to the bomb bays, the rear transparent part of the cockpit canopy was made easily removable.
The bomb bays were loaded from below using a portable winch installed above them on a special farm. In this case, it was necessary to raise the tail of the aircraft above the ground by 0.5 ... 0.6 m or install the aircraft above a trench specially dug in the ground.
It took 20 minutes to hang two FAB-100s, and 25 minutes for four. The suspension of four cassettes with 128 PTAB-2.5-1.5 bombs took 22 minutes.
Normal version of 200 kg bomb load in two forward compartments (PTAB-2.5-1.5 or two FAB-100). The flight weight of the aircraft in this variant is 3356 kg, centering is 23.4% of the MAR, anti-cocking angle during braking is 25°15'. At the same time, the Yak-9B had a certain margin of longitudinal static stability and allowed piloting by medium-skilled pilots with little additional training. A bomb load of 300 and 400 kg was considered an overload option. The flight weight of the aircraft with 400 kg of bombs is 3556 kg, centering is 33.0% of the SAH, anti-boot angle during braking is 34 ° 10 '. In this version, the Yak-9B did not have longitudinal stability. Flights were allowed only in special cases and only for pilots with good and excellent piloting technique.
When the Yak-9B was loaded with two FAB-100 bombs, its speed decreased by 2...3 km/h, and with four bombs by 5...7 km/h. The climb time to 5000 m increased by 0.5 min and 1.5 min, respectively. With 400 kg of bombs and a full refueling (485 kg), take-off became somewhat more complicated. During the takeoff run, the aircraft reluctantly lifted its tail.
To ensure the normal operation of the Yak-9B with 200 and 400 kg, the take-off distance to an obstacle 25 m high had to be 300 ... 500 m more than for the Yak-9D.
Bombing of 300 and 400 kg bombs was allowed only from level flight due to the fact that the Yak-9B did not meet the strength standards of the 1943 edition for dive bombers.
Aimed bombing could be carried out from level flight, on the withdrawal from a shallow dive and from a dive at angles up to 45 °. With appropriate training of the flight crew in bombing on the withdrawal from a dive, it was possible to achieve hitting targets up to 50 m in size. Depending on the bombing mode, there were their own methods and methods of aiming. Special marks were used on the glazed part of the canopy and on the wing, as well as soldiers signaling the position of the landing gear, engine hood, pipes, etc. This required a certain position of the body of the head and eyes of the pilot. In addition, it was required to carry out strictly regulated rotations of the aircraft on the target.
For example, when bombing from level flight, the pilot had to sight the target along the engine hood, then mark a clearly visible landmark in front of the target, and at the moment the target arrived at the nose of the aircraft, continue flying in the same direction for 3 seconds, counting the time by pronouncing the numbers 21, 22, 23, then drop the bombs. The direction of flight during the countdown was maintained according to the landmark.
The modification of the Yak-9D into a fighter-bomber by the Design Bureau was completed in exactly one month - by March 20, 1944. State tests were carried out in four stages: for flight and weighing - on March 23-24, 1944; to determine the characteristics of stability and controllability - May 23 - June 11; control tests of the first serial aircraft - July 12-19; spinning - in July-August 1944 (pilots A.G. Proshakov, Yu.A. Antipov, A.G. Kubyshkin, chief engineer A.T. Stepanets). Military tests of the Yak-9B took place in 330 Iad (division commander, Guards Colonel F.I. Shinkarenko) from December 18, 1944 to February 20, 1945.
2494 sorties with bombing were made, 51047 bombs with a total weight of 356.5 tons were dropped, 53 air battles were conducted, 25 enemy aircraft were shot down, including 20 FW-190, 2 Me-109, 1 Arado-56 , 2 He-129. Losses of the Yak-9B in air battles - 4 shot down and 4 shot down.
As a result of the bombing, a lot of enemy equipment and manpower was disabled and destroyed: tanks - 29, armored personnel carriers - 11, vehicles - 1014, tankers - 17, tractors - 3, guns - 7, steam locomotives - 18, railway vehicles - 161 , station buildings - 20, fuel depots - 4, etc.
Despite the positive results of combat use, the Yak-9B received, according to the results of military tests, in general, an unsatisfactory rating due to the lack of a special sight for bombing; the difficulty of piloting with a bomb load of 500 and 400 kg and full refueling, as well as the presence of such defects as the hanging of aerial bombs during dive bombing at an angle of 45 ... 50 °, the difficulty of loading and unloading the aircraft with bombs, etc.
For this reason, and also due to the imminent end of the Great Patriotic War, only the Yak-9B military series was built (in February-March 1944) in the amount of 109 vehicles. They were fully armed with one 130 iad on the 3rd Belorussian Front, in which one squadron, built at the expense of the artists of the Moscow theater, was called the "Maly Theater - to the Front."
Yalovlev Yak-9DD at Foggia airfield, Italy
The modification was carried out by the Design Bureau in connection with the need that arose in 1944 to have a fighter with an even longer flight range than in the Yak-9D, capable of performing the tasks of escorting bombers during their operations deep behind enemy lines.
Characteristic features of the Yak-9DD: Gas tanks with a total capacity of 845 l (630 kg) - eight main and one expendable, all metal. In this regard, ribs are reinforced in the wing, hatches are installed under the gas tanks, six additional filler necks of tanks. Six internal gas tanks and a supply tank - protected, two console - unprotected; The protector is designed to protect against bullets of 7.92 mm caliber. The tread thickness of the supply tank is 15 mm, six internal gas tanks: top - 1 mm, bottom - 8 mm. Oil tank with a capacity of 70 liters. ShVAK cannon with 120 rounds of ammunition. Special equipment for flights at night and in adverse weather conditions - the SCR-274N radio station with two BTs-454A and BTs-455A receivers and two BTs-457A and BTs-459A transmitters, RPK-10M radio semi-compass, AG-2 attitude indicator, higher main and additional keel of the antenna mast; more powerful generator and battery; an 8-liter oxygen cylinder instead of a four-liter one.
The new radio equipment provided reliable two-way radio communication at a distance of up to 150 km at an altitude of 1000 m and reception at an altitude of 7000 m at a distance of 300 km. From the Yak-9T, the cockpit shift back by 400 mm was borrowed. The flight weight of the Yak-9DD increased by 270 kg compared to the Yak-9D and by 362 kg compared to the Yak-9T and amounted to 3387 kg. On landing, the difference in flight masses was smoothed out. Due to the increase in the flight weight, the tactical flight data with a full load changed significantly: the maximum speed decreased, the rate of climb, maneuverability and takeoff and landing properties deteriorated, but after using up half of the fuel supply, the maximum speed and other data became almost the same as for serial Yak -9D.
Longitudinal stability at full flight weight, due to the centering shift back, deteriorated, but only slightly. The spin characteristics in terms of ease and safety of the output remained practically the same as those of other Yak aircraft. According to the piloting technique, the Yak-9DD, being heavier and inert, was somewhat different from the Yak-9D. Although the takeoff run and takeoff distance increased, however, the Yak-9DD could take off from the same field airfields as the Yak-9D. Due to a significant increase in the fuel reserve (compared to the Yak-9D by more than 30%), the range and duration of the flight have increased significantly. Thus, the flight range to complete fuel burnout at an altitude of 1000 m at 0.9 maximum speed increased to 1325 km, and in the most advantageous mode, up to 2285 km. Flight duration increased to 2 hours 22 minutes and 6 hours 31 minutes, respectively (26% more than the Yak-9D).
The long range and duration of the flight made it possible to use the Yak-9DD as an escort fighter, as well as to independently perform special tasks behind enemy lines.
The modification was made by the Design Bureau in April 1944 in accordance with the GKO decree of February 20, 1944. State tests were carried out at the Air Force Research Institute from July 24 to August 2, 1944 (pilots P.M. Stefanovsky, Yu.A. Antipov, leading engineer M.A. Pronin).
Yak-9DD was mass-produced from May 1944 to September 1945. A total of 399 aircraft were built.
Military tests for combat use were carried out in 368 IAP (commander - Major A.G. Zhulin) 334 IAD 6 tank (bomber air corps) 3 VA from March 9 to April 25, 1945 [TsAMO, f. 35, op. 11287, file 3589]. A total of 40 Yak-9DDs of the 1st and 2nd production series were tested in May - August 1944.
Troop tests in 368 IAP took place during the liquidation of enemy groups in East Prussia and offensive operations in central Germany against the cities of Stettin and Berlin. Air battles had to be fought mainly with the FW-190. Yak-9DDs were mainly used to escort Pe-2 and Tu-2 bombers operating at low altitudes along the front line of the enemy defenses, and therefore could not fully prove themselves. In particular, they did not fully meet the requirements for escort fighters for such a high-speed bomber as the Tu-2 for the following reasons: Relatively low maximum speed. When the Tu-2 flew at maximum speed, the Yak-9DD did not have the necessary advantage (by 25...30%) for joint operations, especially when the Tu-2 left the target and repulsed enemy attacks. To eliminate this shortcoming of the Yak-9DD as an escort fighter, it was necessary to improve its aerodynamics like the Yak-9U and Yak-Z and install a more powerful engine on it, for example, the M-105PF2, but this engine had insufficient altitude compared to the Tu-2 engines .
Reduced rate of climb and lack of maneuverability, especially at full flight weight. Deteriorated survivability due to the installation of a center-wing gas tank (90 l) under the pilot's feet and the lack of protectors on the outer cantilever gas tanks. The survivability of the aircraft also deteriorated due to the large area affected by eight gas tanks in the wing.
Large flight weight, large mass spacing, as well as low engine power were the main reasons for the deterioration of the flight performance and maneuverability of the Yak-9DD. Therefore, the pilots treated the Yak-9DD with restraint, calling it among themselves a "flying tank".
The Yak-9DD had its own specific defects, mainly due to the large flight weight and large fuel capacity. The main ones are the rapid wear of tires on the chassis wheels; breakage of the tail wheel forks; uneven fuel production, which led to air leakage and engine failure in flight.
Armament. One 20-mm ShVAK motor cannon with 120 rounds of ammunition and one (left) synchronous 12.7-mm UBS machine gun with 200 rounds of ammunition.
Yak-9DD fully justified itself as a long-range fighter, when a group of 12 aircraft of this type in August 1944, under the command of Major I.I. Ovcharenko, made a non-stop flight Balti-Bari (Italy) with a length of 1300 km without external gas tanks to assist the People's Liberation Army of Yugoslavia. The leader was the bomber "Boston", led by an experienced test pilot of the Air Force Research Institute M.A. Nyukhtikov. This flight and subsequent work to escort C-47 transport aircraft to the territory of Yugoslavia liberated by the partisans demonstrated the high operational and flight qualities of the Yak-9DD. For the entire period of stay in Vari, not a single case of aircraft breakdown or failure was noted, although in each sortie (and there were 155) it was necessary to cross the Adriatic Sea twice, passing over the water surface from 400 to 600 km, and to land on areas of limited size located among high mountains with a strong side and even tail wind. Yak-9DD at altitudes up to 3000 ... 4000 m in speed and maneuver surpassed all British and American fighters based at Bari airfield - Tempest I, Spitfire IX, P-63C-1 Kingcobra, P-40 " Kittyhawk", P-47 "Thunderolt", etc., which was tested practically in training air battles. Almost all American and British fighters were high-altitude and did not shine with their qualities at 3000 ... 4000 m.
English and American pilots spoke with admiration of the skill of Soviet pilots and the high qualities of the Yak-9DD. In 1944, the Yak-9DD was successfully used to escort B-17 Flying Fortress and B-24 Liberator bombers on a non-stop shuttle flight to targets in Romania from Poltava (Ukraine) to Bari (Italy).