Overcoming in 1943 the shortage of light aviation materials, the TsAGI wind tunnel re-evacuation, as well as the experience gained, allowed OKB AS. Yakovlev finally begin to create a fighter capable of gaining air superiority on the Eastern Front. The basis was taken well-developed and finished fighter Yak-1. Its design was revised and a thorough audit of the weight of all parts was carried out.
Replacing heavy wooden wing spars with duralumin ones, facilitating some parts and components of the structure, reducing the geometric dimensions of the wing (the span became smaller by almost 1 m, and the area by 2.3 m2) made it possible to reduce the weight of the aircraft to 2655 kg (compared to 2880— 2900 kg in the serial Yak-1) and thereby increase the power and maneuverability of the machine. Sometimes such decisions were contrary to established ideas, but at the same time, they were amazingly simple.
Radical improvement of the overall aerodynamics of the aircraft was also carried out by carefully finishing the wing and fuselage. Cladding for the tail section was replaced with plywood. The oil cooler tunnel was drowned as much as possible into the engine room. The tail wheel was made retractable. The aircraft with the M-105PF engine, called Yak-Sh (“M” – “Mosquito”), was built in February 1943, underwent factory tests until June and state tests until August. The maximum speed, compared with the serial Yak-1, increased by 40 km / h.
On the second experimental aircraft (backup), released in September 1943, a new forced engine M-105PF-2 with an increase of 110 hp was installed. power. At the same time, according to the new layout of the engine cooling system, the oil cooler with a large cooling area was replaced by two round ones, connected in parallel and placed in the center section, under the floor of the cockpit. The absence of an oil cooler tunnel under the engine significantly improved the external contours of the lower hood. Complex measures were taken to aerodynamically improve the aircraft. Reducing the relative thickness and area of the wing, excellent aerodynamic forms, combined with a lightweight design and greater engine power, provided the new fighter with high speed and excellent maneuverability, especially vertical.
The results of state tests conducted in October showed that the flight data of the understudy improved compared with the first prototype aircraft. He developed a speed of 570 km / h near the ground, at an altitude of 4300 m – 651 km / h (for the serial Yak-1, 531 and 592 km / h, respectively). During a combat turn, he gained 1250–1300 m in height, 5000 m in height in 4.1 minutes (for the Yak-1b, respectively, 1000 m and 5.6 min). In the act, where the results of state tests were summarized, it was noted that the idea of a “light fighter” was successfully embodied in this aircraft. In terms of the rate of the climb up to a height of 6000 m, the aircraft was second to none among the famous fighters.
The prospect of an aircraft with an M-105PF-2 engine was obvious. The fighter had a finished shape and was easy to control. Under the designation Yak-3, the understudy was recommended for serial production, to replace the Yak-1.
Mass production of the Yak-3 was organized at two plants. The first plane was ready on March 1, 1944, i.e. almost five months after the completion of state trials of the understudy.
Soviet pilots, quickly mastered the Yak-3, skillfully used its high qualities, dictating the conditions of the battle to the enemy. In a maneuvering battle with the German fighter Bf-109, the Yak-3 came into its tail from the first vertical turn and after three or four turns horizontally. Fighter FW-190, as heavier, lost the Yak-3 even more.
Luftwaffe experts closely monitored the work of OKB AS Yakovlev. In 1944, in connection with the appearance of the Yak-3 at the front, the German command sent a directive to its aviation units in the East, which ordered them to avoid battles with Yak fighters that did not have an air intake under the hood at altitudes up to 5 km and below.
The Yak-3 was one of the lightest and most maneuverable fighters of the Second World War. These aircraft were mass-produced until 1946 – the time of the appearance of jet fighters. A total of 4848 Yak-3s of various modifications were produced.
The first Soviet serial jet fighter was the Yak-15, which rolled off the assembly line in April 1946. To create it, the Yak-3 glider was used with minor design changes necessary to replace the piston engine with a turbojet. In a well-known cockpit, combat pilots felt familiar and easily mastered a new plane.
- The frame of the fuselage Yak-3 – truss, welded from steel pipes. Duralumin easily removable panels on the sides provided free access to the equipment of the cabin;
- Through the hollow shaft of the screw passed the barrel of the gun installed in the collapse of the engine cylinders;
- The exhaust pipes are made individually for each cylinder;
- On the Yak-3 cockpit, instead of a faceted visor with front bulletproof glass, a new one-piece visor of an improved form was installed. The movable part of the lantern was equipped with special emergency reset mechanisms .;
- The pilot’s seat had a steel armored back and a bulletproof headrest;
- The orienting crutch wheel, retractable, was closed in flight by shields;
- To reduce the drag of the tunnel water cooler. he was maximally “drowned” in the fuselage;
- One-piece wing of mixed design, with plywood sheathing, perceiving power load. Between duralumin spars there were two protected gas tanks;
- The wing is equipped with landing flaps;
- When the chassis was removed, the niches were closed by shields. The position of the landing gear was signaled by pins (“soldiers”), which, when the landing gear was extended, protruded above the upper wing skin; At the front edge of the wing, near the fuselage, there were air intakes for cooling air to enter the oil coolers and engine supercharger;
Yak-3 (serial). It was produced since 1944, only with the M-105PF-2 engine, but with various weapons options. In 1944, the ShVAK gun and the UBS synchronous machine gun were installed. There was a lightweight version of the aircraft – only with a ShVAK gun. In 1945, the Yak-3 was produced with a ShVAK gun and two synchronous UBS.
Yak-3 – VK-107A (1944). With a 1,650 hp engine with a flight weight of 2984 kg, a speed of 720 km / h was reached at an altitude of 5750 m on this experimental vehicle. The state test report noted that the Yak-3 with such a motor at all altitudes has high flight technical data, is stable and easy to operate, It has powerful weapons. However, difficulties arose with the engine due to its excessive forcing and lack of knowledge. Machines produced in a small series did not have time to take part in the hostilities. Armament was provided in two versions: a 20-mm gun and two UBS machine guns, or two synchronous guns.
Yak-3 – VK-108 (experimental). In August 1944, the design of the Yak-3 modification was started for the new M-108 engine (1800 hp) with the NS-23 gun. The first flight took place on December 19th. During the tests, record flight data were obtained: with a flight weight of 2896 kg at an altitude of about 6,000 m, the aircraft developed a speed of 745 km / h, reached an altitude of 5,000 m in 3.5 minutes. The test program could not be completed due to numerous complications with the engine, which had a very intense thermal regime. Neither the engine nor the aircraft was finalized.
Yak-3RD (Yak-3R) – experienced, with a combined power plant. In 1944, OKB AS. Yakovleva was one of the first to work on obtaining a significant increase in speed on a piston fighter. For the experiments, the serial Yak-3 with the M-105PF-2 engine was selected. As a temporary accelerator, an RD-1 liquid-propellant rocket engine installed in the rear of the fuselage under vertical tail was used. Tanks with fuel for the auxiliary engine were under the cockpit. The tests, during which several accidents occurred, were interrupted on August 16, 1944. For unknown reasons, a catastrophe occurred. The test pilot died. Work on the aircraft was discontinued due to the under-operation of the RD-1 engine. A short-term speed increase of up to 782 km / h was achieved. In 1945, similar experiments were carried out at OKB SA Lavochkina, AI. Mikoyan and P.O. Dry.
The Yak-3U is an experimental version of the Yak-3 with a star-shaped air-cooled engine ASH-82FN (1850 hp). Built in early 1945, it made its first flight on May 12. With a take-off weight of 2792 kg at an altitude of 6000 m, a speed of 705 km / h was achieved (for comparison: for La-7 – 3265 kg and 680 km / h, respectively). Armed with two synchronous ShVAK guns mounted above the engine. According to testers’ estimates, the aircraft was quite successful, but it did not start mass production since it was deemed inappropriate to establish the release of a new piston fighter after the end of the war.
Yak-3T – heavy. On the serial Yak-3 with the M-105PF-2 engine, the NS-37 gun and the UBS synchronous machine gun were installed. Built in a single copy in 1945.
Yak-3UTI – training double fighter. Structurally similar to the serial Yak-3. To install the star-shaped air-cooled engine ASH-21 (570 hp) and the seats of the cadet and instructor, the fuselage had to be changed. It was slightly expanded, and therefore the wingspan increased by 200 mm. The cabin light from the Yak-9V (export) was used.
Management was double. The upper and lower parts of the fuselage behind the cockpit were lined with plywood, along the sides with canvas. Armament: UBS machine gun (100 rounds) to the right above the engine and 50-100 kg of bombs on two holders. The first flight took place on November 10, 1945. With a take-off weight of only 2250 kg at an altitude of 2550 m, a speed of 478 km / h was achieved. Serially not built, becoming the prototype for the Yak-11.
Yak-3P (cannon) – modification of the Yak-3 with three guns B-20 design M.E. Berezina. Built in 1946
The superiority of the Yak-3 in speed, climb and maneuverability at altitudes from the ground up to 5000 m over all types of enemy aircraft was staggering. Outwardly similar to its predecessor – the Yak-1, he repeatedly misled the German pilots. So, the battle conducted by pilots of the 91st fighter regiment on July 16, 1944, in which new Yak-3s were undergoing military tests, 18 Yak-3 fighters met with a mixed group of 24 aircraft Bf 109G-2 and FW 190A-4. In the battle 15 enemy aircraft were shot down and. only one Soviet fighter.
The Yak-3 fighter really liked the pilots, because in their expression he “went well for gas” – he was distinguished from the rest by better pick-up.
- wingspan, m – 9.2;
- length, m – 8.5;
- height, m – 2.42
- wing area, sq. m. – 14.85;
- normal take-off weight, kg – 2830
- engine – VK-105PF2;
- power, l from. – 1800 h.p.
- Max. speed, km / h – 645;
- practical range, km – 1060;
- Max. rate of climb, m / min. – 1111;
- ceiling, m – 10700;
- crew – 1 person