The Yak-7 is a Soviet single-piston fighter of the Second World War period, created at the Yakovlev Design Bureau on the basis of the Yak-7UTI training machine. The release of the aircraft began in late 1941 and continued until 1944. Yak-7UTI, being developed for training flight personnel, underwent a number of amazing transformations in the future and played a very important role in the history of the Great Patriotic War.
During the production, eighteen different modifications of this fighter were developed, ten of which went into mass production. In total, more than 6,300 Yak-7 aircraft were produced. Since 1942, the “seven” at the front began to be gradually supplanted by the Yak-9 fighter, which later became the most massive Soviet military machine of the military period.
Despite some shortcomings, the pilots were very good about the Yak-7. The quality of their manufacture was often higher than that of the Yak-1 fighters, on the basis of which they were created. Excellent flight characteristics and powerful weapons allowed the pilot not only to stand up for themselves in battle but also to get out of it as a winner.
Compared to the Yak-1, the Yak-7 fighter was more developed, a number of improvements were made to its design, which made this machine more manageable, safe and easy to maintain. The Yak-7 aircraft was launched at four aircraft factories: No. 82 and No. 301 (Moscow), No. 21 (Gorky) and No. 153 (Novosibirsk).
History of creation
At the end of the 30s, frantic work was going on in the Soviet Union to create a new modern fighter. The best domestic design bureaus were attracted to it: Lavochkina, Mikoyana, Yakovleva. It was planned to build a new machine in large quantities, so almost immediately the question arose about the most rapid development of a fighter in combat units. What was needed was a modern training aircraft, the characteristics of which would not be inferior to new combat vehicles. Its development was entrusted to the design bureau under the leadership of Alexander Sergeyevich Yakovlev.
Work on the new training aircraft began back in 1939, the Yak-1 fighter was taken as the basis, the development of which at that time was the designer’s design bureau.
On March 4, 1940, a resolution of the Soviet government appeared on the creation of a training fighter based on the I-26 prototype aircraft.
Tests of the training machine began in the summer of 1940, the aircraft showed very good flying qualities: at an altitude of 4,500 meters, it was able to reach a speed of 586 km / h. However, the UTI-26 (the training fighter received this name) was too difficult to pilot, which was unacceptable for novice pilots, so the car had to be modified.
In addition, the first prototype of a fighter (it was called UTI-26-I) had a lot in common with the I-26 and therefore suffered from almost all of its shortcomings: the engine often overheated, oil was often released from the oil system, which splattered the entire front of the aircraft, including a lamp of a cabin. The chassis design was particularly unsuccessful. The diameter of the wheels did not match the weight of the aircraft, the locks that kept the landing gear in the retracted or released position were extremely unreliable, which led to an accident during the tests. UTI-26-I had a strong tendency to cabotage.
Despite the identified shortcomings, they decided to launch the car into mass production, however, after serious revision. The need for the Soviet Air Force in a training aircraft was so great that even the incomplete UTI-26-I was immediately sent to 11 IAPs to retrain pilots on the Yak-1.
Improvements were made to the design of the second prototype – UTI-26-II. The landing gear of the aircraft underwent major changes: the diameter of the landing gear wheels was significantly increased, the racks and locks themselves were reworked, which fixed them in extreme positions. The area of the stabilizer and rudder has increased markedly – this has significantly improved the controllability of the aircraft. The center of gravity of the car was shifted, the water radiator was increased and pushed forward. Other, less significant, changes were made to the design of the machine. So, for example, the method of fastening the Coca screw was changed, after which its installation began to take much less time. Modernization of the aircraft increased its weight to 2750 kg.
Despite the fact that the UTI-26-II looked very much like the Yak-1, structurally it was different cars. This caused some technical difficulties in production because Yak-1 and UTI-26 were supposed to do at the same plants. State tests of the aircraft took place in early 1941. The modified prototype of the fighter received from the military a much higher rating than the UTI-26-I. The need for a training aircraft was very acute, so in March 1941 the Moscow aircraft plant No. 301 was transferred from the production of the Yak-1 to the production of the Yak-7UTI.
When the UTI-26 was just being created, no one could have imagined that someday a full-fledged combat fighter would be created on its base. However, the huge losses of the Soviet Air Force at the initial stage of the war forced to take such a step. At the suggestion of the young designer Sinelytsikov, the standard weapons of the Yak-1 were installed on the plane. Initially, such an idea was perceived ambiguously by many, but Yakovlev gave the green light to remaking one aircraft. A duplicate control was removed from it in the second cockpit, an armored back and fuel tanks were installed, protected by a tread with a neutral gas pumping system.
Tests of the “armed” version of the UTI-26 began in June 1941, a few days before the start of the war. The report of the pilot who conducted the tests of the fighter noted his best aerobatic qualities compared to the Yak-1. The new aircraft received the designation Yak-7. The combat use of the machine showed that the Yak-7 fighter is superior to the Yak-1 in survivability, armament, and maneuverability.
After the outbreak of war, the alteration of a training aircraft in combat was also supported by the GKO. Already in August, relevant decrees were issued. Serial production of the Yak-7 aircraft began immediately at two plants: No. 301 and 153. At that time, the evacuation of aviation enterprises and research institutes took place, so they decided not to conduct state tests of the Yak-7 and limited themselves to factory ones.
In July 1941, the Yakovlev Design Bureau was evacuated to Saratov, where the designers literally in a matter of days proactively developed a cannon modification of the fighter – the Yak-7M, installing ShVAK guns in the wing. Also, launchers for rockets were installed on the aircraft. To do this, however, it was necessary to reduce the volume of fuel tanks. In October 1941, flight tests of a new fighter began.
Yak-7. The basic modification of the machine, production lasted from September to October 1941. A total of 62 units were manufactured.
Yak-7A. Modification of the fighter, the release of which began in January 1942. The aircraft was equipped with a new radio station, minor changes were made to the design of the airframe. Production continued until May 1942, a total of 277 Yak-7A units were produced.
Yak-7B. The most massive modification of the machine, its production began in May 1942 and continued until December 1943. During this period 5120 aircraft were produced. The Yak-7B had two UBS machine guns instead of the ShKAS, a retractable tail chassis, and from the middle of 1942 a new engine, the M-105PF. The new power plant, as well as a number of other changes, allowed to increase the speed of the fighter to 532 km / h near the ground. In the last series of this modification, the gargroth was removed, the fuselage contours and its sealing were improved, which allowed to further increase the speed characteristics.
Yak-7V. Training fighter, which was manufactured by removing weapons from the serial Yak-7B. It was produced from May 1942 to December 1943. 597 aircraft were manufactured.
Yak-7-37. Modification armed with a 37 mm MPSh-37 cannon and two UBS machine guns. This fighter had a slightly different cockpit layout, slats a slightly larger tailwheel.
The Yak-7 is a single, single-engine monoplane fighter with a low wing and a mixed design: in the manufacture of the machine both duralumin and wood with canvas were used. The crew of the aircraft consisted of one person.
Like other fighters of the Yak family, the Yak-7 power frame was made of chrome-force pipes, an engine mount was attached to the front of it. An advantageous difference between the Yak-7 and other Yakovlev machines was that a removable motor frame made it possible to install other engines on the plane. The skin of the front of the fighter was metal, and the tail of the Yak-7 was sheathed with plywood.
The cockpit was located in the central part of the fuselage. The Yak-7 was created on the basis of the Yak-7UTI training aircraft, which had two cabins – for the pilot and instructor. On the combat aircraft, the second cockpit was removed, in its place was an additional compartment, closed by a lid. It could be used to transport goods, another person, or install an additional gas tank.
The Yak-7 wing had a mixed design: two duralumin spars, wooden ribs and a working panel made of plywood. The wing was additionally pasted over with a cloth.
The tail unit of the Yak-7 consisted of a wooden keel and stabilizer, the rudders were made of duralumin and sheathed with canvas. The aircraft had a tricycle retractable landing gear in flight, which included two main struts and tail support. On the first modifications of the car, the tail wheel was not cleaned in flight. Like other Yakovlev fighters, the Yak-7 had a chassis with air-oil cushioning, and the landing gear was cleaned and released using a pneumatic system. In the retracted position, the chassis was closed by shields.
Initially, the Yak-7 fighter was equipped with a water cooling engine M-105P (1050 hp), then more powerful engines (M-105PA, M-105PF) were installed on the plane. The fuel tanks of the car were designed and located in the wings: two in the wing consoles and one in the center section. The aircraft had an inert gas pumping system, which increased its fire safety.
The oil cooler was located in the front of the fighter in a special tunnel under the engine, a water radiator was installed in the central part of the fuselage just behind the cockpit. In winter, antifreeze was added to the water, and gasoline was added to the oil.
The training Yak-7UTI had no weapons at all, the Yak-7 received a 20-mm ShVAK gun, which was in the collapse of the engine, as well as two ShKAS machine guns (7.92 mm). The ammunition of the gun was 130 rounds, machine guns – 1 thousand rounds. Several rockets or 100 kg of bombs could be suspended on a modification of the Yak-7A aircraft. The most massive modification of the Yak-7B fighter was armed with one ShVAK gun and two 12.7 mm UBS machine guns, which significantly increased the firepower of the machine. In combat reports, it was noted that after the installation of more powerful UBS machine guns, the Yak-7 became effective for working on both air and ground targets.
The Yak-7 fighter took part in all the major battles of the Second World War. The additional cabin of this aircraft was often used to transfer personnel or cargo to new locations. An additional fuel tank could be installed in the rear compartment. Often, photo equipment was installed in the rear cockpit, and the Yak-7 turned into a reconnaissance vehicle.
- wingspan, m – 9.74;
- length, m – 8.37;
- height, m – 2.75;
- weight, kg – 3370;
- engine – ASh-82;
- power, l from. – 1330;
- Max. speed, km / h – 615;
- practical range, km – 825;
- practical ceiling, m – 10200;
- crew – 1.