Yak-7B M-105PA - Yakovlev
Yak-7 was a Soviet single-seater piston fighter of the Second World War, created in the Yakovlev Design Bureau on the basis of the Yak-7UTI training vehicle. Even before the LaGG-3, MiG-3 and Yak-1 fighters were put into service, and the organization of their mass production, the task appeared to speed up the development of these aircraft in service. It was not advisable to create a completely new training aircraft, which had nothing in common with the specified fighters, and therefore it was decided to create a transitional two-seat dual-seat training fighter named UTI-26 (later Yak-7) by modifying an experimental fighter I-26 (later Yak-1).
The airplane was launched at the end of 1941 and lasted until 1944. Yak-7UTI, being developed for flight crew training, underwent a number of surprising transformations and played a very important role in the history of the Great Patriotic War. The idea of turning the Yak-7 into a combat fighter occurred to the young engineer Konstantin Sinelschikov. Many thought the idea was ??delirium. Even A.S.Yakovlev listened to the designer with a smile, but after a while gave the task to complete one training aircraft. The alterations, of course, were reduced to a minimum: in the collapse of the engine's cylinders, a SHVAK gun was installed, and above the motor there were two SKASs, the rear cab was retained, but the equipment was removed from it. Subsequently, mechanics and small tools were transported there when relocating, and this became an important advantage of the machine.
The fighter, named Yak-7A, was enthusiastically received by the pilots and already at the end of 1941 appeared at the front. The pilot S. Suprun, who conducted the tests of the upgraded fighter in June 1941, noted in his report that the Yak-7 piloting technique was better than the Yak-1. The plane listened well to the rudders, was more stable, performed bends at a minimum speed of 200 km / h. When executing the "loop", the machine maintained controllability at the top point even at a speed of 120 km/h.
Initially, the Yak-7 fighter was equipped with a water-cooled M-105P (1050 hp) engine, then more powerful engines (M-105PA, M-105PF) were installed on the aircraft. The fuel tanks of the car were protected and located in the wings: two in the wing consoles and another in the center wing. The aircraft had a pumping system with inert gas, which increased its fire safety. The oil cooler was located in 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 of the pilot. In winter, antifreeze was added to the water, and petrol was added to the oil.
During the serial production, the Yak-7 fighter was repeatedly upgraded, more than a dozen different variants were built. So, in early 1942, the Yak-7b version was commercially launched. It installed a more powerful engine M-105PF. holders for six PC shells or small bombs, SHKAS machine guns were replaced by large-caliber aircraft. Yak-7B M-105PA was a further development of serial Yak-7A and differs from it with more powerful weapons and aerodynamic improvements.
The armament of the Yak-7B consisted of motor-gun ammunition ShVAK with 120 shells and two synchronized machine guns UBS with a total of 400 rounds of ammunition (left gun - 260, right - 140). Furthermore, under the wing could hang six RS-82 or two bombs 25 to 100 kg each. Armament was successfully tested on the Yak-7B N22-03 in June 1942 for the shooting of weapons was carried out 25 flights for a total of 7 hours 57 minutes. According to the decision of OPK on May 10, 1942 Yak-7B was produced. The Yak-7B fully implemented the recommendation of TsAGI to improve aerodynamics.
For a more comprehensive use of high-speed pressure and altitude, the aircraft increased the boundaries of improved engine intakes. Inlet pipes were flush with the surface of the wing fairings and slightly bent down. The grid was tilted and sunk inside, and. produced with sealing channels.
The tail wheel was made fully retractable-type UTI-26-2, with it in the fuselage was closed two-folding side shields instead of a windshield. Improved exterior design of the aircraft, as well as the adjustment of the flaps, fairings, hatches, sections of the engine hood, etc. To increase the engine speed to 2350 ... 2600, 2550 ... 2700 rev / min, it was necessary to increase the take-off and other characteristics of the aircraft, whereby the angle of the blades propellers on-61P small gas decreased from 23 to 20 degrees.
To reduce the temperature of the water and oil to the limits and thereby ensure the possibility of using the nominal engine speed at takeoff, climb and level flight at maximum speed set improved water tunnels and oil cooler. The walls of the flap radiator were made higher, to eliminate the "scissors" between the tunnel and the damper. The output of the oil cooler of the tunnel was reduced.
Flight characteristics of the Yak-7B, despite the presence of mast radio station, installation of new weapons, which caused a strong distortion of the upper section of the hood of the engine and increase flight mass compared to the Yak-7A and UTI-26-2, were significantly higher than Yak-7A and almost identical to the characteristics of UTI-26-2.
After replacing the machine guns on ShKAS UBS fire power Yak-7B was broadly consistent with the needs of the front and could be more effective than the Yak-7A and other aircraft used by both air and ground targets. Second salvo weight reached 2.72 kg / s and superior characteristics of the Yak-1, Yak-7 and Yak-7A 1.57 times, LaGG-Z later releases - 1.36 times, MiG-Z - 2.26 ... 2.56 times, La 5 - 1.55 times, Me-109F - 2.87 times and Me-109G-2 (three point) - 1.62 times.
The standard Yak-7B M-105PA on 1942 (aircraft N14-13) held joint factory and state tests at the airport of Novosibirsk plant N153 from January 28 to February 5, 1942. In the report on the state testing Yak-7B was noted that in comparison with the Yak-1, well proven in the front, the Yak-7B was structurally more sophisticated and promising ... Unlike some other fighter aircraft in the Air Forces of the Red Army, the Yak-7 for the time spent in serial continuously improve manufacturing constructive and equipped with new, more powerful weapons (PO, machine guns UBS) and special equipment (headlights, radio transceiver, radiopolukompas etc.), without losing its battle and flight data. This positive development has taken place thanks to the skillful approach to the issue of equipping the plane with new weapons and special equipment, and systematic work to improve the EDO Flight Data production aircraft.
A comparison of the Yak-7B with LaGG-W, MiG-West, I-16, I-153, Me-109F, Me-110, He-100, as well as some American and British fighters coming to the Soviet Union, concluded that in respect of stability and controllability of the airplane Yak-7B M-105PA not only equal, but superior to the best samples of domestic and foreign fighters.
After the state tests, it was decided on the transfer of OPK with the serial production Yak-7A on the Yak-7B. The Yak-7B M-105PA was produced at the plant N 153 between April and July 1942, all 261 aircraft was built. The aircraft performed well in the battles of Stalingrad and the Kuban.
Increasing the mass of weapons led to a shift in alignment forward and unacceptable reduction in opposite [protivokapotazhnogo] angle. Therefore, to avoid "nosing", aircraft from 20 May 1942 installed additional fuel tank in the rear cockpit , with a capacity of 80 liters (60 kg). The pilots were unhappy with the installation of the gas tank , as it increased the weight of the fighter and therefore worsened performance of the aircraft and, in addition, increased fire danger. During the Battle of Stalingrad, this tank was recognized as unnecessary, and it was removed from the aircraft without instructions from above. Officially, it was authorized by resolution of OPK on September 22, and from October 1, 1942
The commander and commissar 202 IBP Jansen and Loban, assessing fighting qualities of the Yak-7B, wrote that the Yak-7B in their tactical flight data and weapons was the best fighter aircraft the Air Force used, especially in comparison with the aircraft LaGG -s and MiG-W. The Yak-7B was easy in all types of piloting technique, stable flight, and easy to operate.
From the experience of many air battles to the following conclusions: 1. The Yak-7B easy to lead a dogfight with the Me-109 turns and verticals. On horizontal figures Yak-7b had an advantage and quickly enters the tail of Me-109. The horizontal velocity of the Yak-7B and Me-109 were identical. 2. From Me-109F, the Yak-7B lags behind the vertical figures. This was explained by the fact that the Yak-7B slowly picks up speed, and Me-109F "goes for gas." The horizontal speed of the Yak-7B compared to the Me-109F in a dive was also lagging, although almost horizontally and dive our pilots had to chase the Me-109F a very short time. So full conclusions could be drawn. Perhaps at long horizontal flight and dive Yak-7B can catch up with Me-109F.
The main disadvantages of the Yak-7B: 1. heavy, making it difficult to set a fast speed. 2. Has a high resistance due to water and oil radiators. 3. Do not have a rear view mirror. 4. Bad celluloid in the lamp, which makes it difficult and makes it impossible to fly with closed hood. 5. Engine (especially not boosted) corresponds in its weight capacity of the aircraft. 6. When shooting, moving the hand from the throttle and moving the trigger impairs control of the aircraft, as well as knocks accuracy of the sight. 7. The path length and takeoff run high that requires good "sites" in length.
The Yak-7B with a souped-up engine M-105PF was a front-line fighter and was distinguished from its predecessor Yak-7B M-105PA, mainly engine power, increased from 1050 to 1180 hp Increased capacity at the ground and at medium altitude was achieved by changing the automatic adjustment of the boost regulator R-7 in the direction of increasing the boost pressure p_k from 910 to 1050 mm Hg.
To ensure reliable operation in the forced mode piston pins were reinforced and modified carburetor adjustment. Other structural differences from M-105PA engine M-105PF had.
Initiative boost for naturally aspirated engine M-105PA belonged Yakovlev Design Bureau, which was in the beginning of 1942 on the serial Yak-7A N22-41 conducted an experiment to increase the boost pressure of the engine series 950, 1000 and 1050 mm Hg and as defined in the flight of the effects was to increase the maximum speed and other characteristics of the aircraft.
The experimental results had been very encouraging, and formed the basis for government decision-making by V.Ya.Klimova in the shortest possible time to transfer the engine M-105PA from normal to boosted operation.
In addition to setting the turbo-charged ["forced"] engine Yak-7B (22 Series) carried out a number of measures aimed at improving aerodynamics and reducing flight aircraft weight, mainly by improving and facilitating the structural elements, without sacrificing durability and damage to the combat and operational qualities plane.
The main changes were: facilitated fuselage; simplified and facilitated hoist seat (adjusted only on the ground); installed a new soft and lighter seatback to the plexiglass hood folding rear cockpit replaced with plywood; Mooring nodes removed; facilitated frame and wheels lining domes in the wing; re-made formwork fuselage facilitated chassis (removed towing rings set new upper cups and the half-line, dropped jet guns and wiring them, due to the intensification of the motor in the propeller hub introduced an additional adjustment ring, resulting in the installation angle of the propeller blades on a small step increased from 20 to 23 degrees.
There were no armaments differences from the Yak-7B M-105PA; of special equipment the only difference was that the cockpit was made in full accordance with the requirements of the standard cockpit fighter. The report on the state testing Yak-7B M-105PF noted that in its scope and placement, as well as on the culture of installation, special equipment Yak-7B was one of the first places among similar types of aircraft both domestic production and enemy aircraft.
At Yak-7 with M-105PF had less range at speeds close to the maximum. Thus, at a maximum speed of 0.9 second in the altitude range of the border decreased from 700 to 645 km. However engine, similar to the modes M-105PA, range has not changed much. Yak-7B N22-41 mounted with a high-revving engine M-105PF passed state tests in the Air Force Institute from May 30 to June 9, 1942, performed 36 operations for a total of 23 hours.
In 1943, at the Novosibirsk plant control tests were conducted 13 Yak-7B M-105PF - 0.6 minutes less. Based on the analysis of the data, it was concluded that in 1943 the Novosibirsk Plant GKO order of 2 November and 9 December 1942, the maximum velocity of the Yak-7B with uprated engines are made.
Also in 1943 were conducted joint (OKB and LII) test Yak-7B 31 Series (N31-01) with uprated engines. The main differences of the aircraft: the antenna mast and the antenna retracted into the fuselage; socks wing and tail are polished to 30% of the chord; installed jet exhaust pipes of two options: EDO - 8 pcs. and the Air Force Institute - 12 pcs. Nozzles are enclosed in fairings on the type Me-109; Thoroughly sealed spinner and the entire aircraft to eliminate air flow and reduce drag; improved fit are parts in the airflow; made efforts to ensure full cleaning in-flight tail wheel size 300h125 mm, with a double wing flaps shut; eliminated the gap between the handlebars, etc.
A study improved aerodynamics Yak-7B M-105PF gave it a three-point advantage over the Me-109G-2 at the ground at 23 km / h and at an altitude of 1000 m - 16 km / h. At an altitude of 5000 m Me-109G-2 was superior to the speed of the Yak-7B M-105PF 23 km / h. Above 5000 m speed advantage Me-109G-2 was even more pronounced and reached 80 km / h.
Yak-7B M-105PF serially produced at two factories - Novosibirsk N153 from August 1942 (22 Series) to December 1943 (50 th series) and the Moscow N82 - May 1942 (with the 1st series) to July 1944 (28 nd series). Aircraft Factory N82 had a flight weight 25-30 kg more, and a maximum speed of 15 km / h less than the aircraft factory N153.
Total production was 5120 for the Yak-7B M-105PF. They took part in the fighting for the first time in August 1942 at Stalingrad.
Directly at the front brigade Yakovlev Design Bureau work was done to improve the viewing back from the cockpit of the Yak-7, M-105PF - gargrot cut, given a drop-shaped lantern shape. From 17 November to 13 December 1942 of the North-Western Front in the 42 IAP (commander F.I.Shinkarenko) 240 IBP 6 VA combat tests were carried out on the combat use.
Results of the tests: 242 sorties, 6 air battles, shot down four enemy aircraft, including: Me-109F - 2, He-126 - 1 and FW-189 - 1; their losses - one Yak-7B. Cab with improved visibility was welcomed pilots and has been recommended for use on all types of fighter aircraft.
The Yak-7B M-105PF was intended for use in air defense system, additionally equipped radiopolukompasom RPK-10, landing light FS-155 on the left wing and electro- light signaling stowed gear. The air defense system delivered 20 Yak-7B aircraft every month.
Despite some shortcomings, the pilots had good things to say 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 himself in battle, but also to emerge as a winner.
During the production, eighteen different modifications of this fighter were developed, ten of which went into mass production. In total, more than 6300 Yak-7 aircraft were produced. Since 1942, the Seven at the front was gradually replaced by the Yak-9 fighter, which later became the most massive Soviet military machine of the war period.
|Year of adopting||1942|
|Wing area, m2||17.15|
|- Empty aircraft||2490|
|- Normal take-off||3010|
|engine type||1 PD M-105PF|
|Power, hp||1 x 1180|
|The maximum speed, km / h|
|- Near ground||514|
|- on high||570|
|Practical range, km||645|
|Rate of climb, m / min||862|
|Service ceiling, m||9900|
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