Fighter First flight: 1943 Yakovlev

Yak-9U with VK-105 PF 2M engine and VISh-105 V-1 propeller (improved) is the latest and most advanced modification of the Yak-9 with M-105 engine. The aircraft was built on the basis of the Yak-9T and differed significantly from the latter: the central part of the wing was changed due to the installation of an oil cooler at the root of the wing of the Yak-3 type, mass compensation was removed from the ailerons, canvas partitions were installed between the wing and the ailerons, covering the gaps, and locks on the landing gear fenders. The leading edge of the wing has become polished. The rear fuselage is sheathed with 2 mm plywood, two baffles were added to improve sealing, tail wheel stop control was moved from the pedals to the control stick. Booking after installing the armrest and headrest, front and rear armored glass provided protection against 7.62 mm bullets (which were almost never used on German fighters or even bombers) at vertical angles of + 30 ° - -15 °, horizontally - ± 20°. The engine power reached 1180 hp, the tanks were protected, as on the Yak-9DD with a fuel reserve reduced to 320 kg, the oil tank capacity decreased to 25 kg. All aircraft radiators were replaced with new ones with a larger surface, the ART-41 water control automatic became standard, the design of the carburetor intake pipe was changed, and individual engine exhaust pipes were installed. The main weapon of the Yak-9 - the ShVAK cannon - was replaced with a more powerful VYa-23 (this gun was developed by Volkov and Yartsev and had a 23 mm caliber with 60 rounds of ammunition) and two UBS machine guns with 340 rounds of ammunition (170 per barrel) . It was even possible to transform the fighter for the installation of both ShVAK and NS-37, although in the latter case one of the machine guns would have to be removed. The control of the radio station became push-button, installed on the gas sector, and the capacity of the oxygen cylinder was increased to 4 liters (on the Yak-9 of previous modifications, the oxygen supply was smaller). The aircraft was also not mass-produced, because. its range fell to 850 km in the most advantageous mode, which means that in combat it became unacceptably small. This lightweight fighter weighed 2990 kg and in factory and state tests showed the best flight performance of all the Yakovs built before. The experimental machine was built in the Yakovlev Design Bureau in one copy in November 1943 and completed the flight test cycle on March 11, 1944 (pilot V. Khomyakov). The resource of the modification with the VK-105 engine was completely exhausted.

Experienced Yak-9U with M-105PF-2 engine built in 1943

The Yak-9S with the VK-105PF engine and the VISh-105SV-01 propeller differed from the serial Yak-9M by installing a powerful weapon from two B-20S guns (B-20 is an aircraft gun designed by Berezin) 20 mm caliber with 220 rounds and VYa-23 23 mm cannons in the engine cylinder camber (in place of ShVAK). This version was built in the form of two prototypes in May 1945. The aircraft passed factory tests from May 10 to May 28, 1945, and from August 28 to September 14, 1945 - state tests. However, despite the very successful armament, this aircraft differed markedly in flight and flight characteristics, as well as in speed and rate of climb from the Yak-3 with the VK-105PF2 and the Yak-EU with the VK-107A. Its speed turned out to be almost fifty kilometers less than that of its competitors, and it gained a height of 5000 m by 1.9 minutes. longer than the Yak-3 and 1.6 min. longer than the Yak-9U. As it did not meet the requirements for flight data, the Yak-9 C was not launched into serial production.

Yak-9U with VK-107A engine was the same Yak-9U, but with a new powerful VK-107A engine and new water and oil coolers OP-554 and OP-555, respectively. The engine power reached 1500 hp, the aircraft was equipped with a new three-bladed propeller VISh-107LO with a diameter of 3.1 m. A closed-type engine cooling system and another exhaust system were installed, consisting of two internal exhaust manifolds and 12 separate external pipes. To increase the rollover angle and improve the centering of the aircraft with a heavier engine, the wing was moved forward by 100 mm, and the elevator area was reduced from 1.15 to 1.13 sq.m.

The cannon armament was the same - 20-mm ShVAK, but now with two UBS and the same ammunition load of 340 rounds. The aircraft was equipped with a mastless single-wire antenna and a GS-15-500 generator. The flight weight was 3150 kg.

An experienced fighter was built in December 1943. It passed factory tests by December 28, 1943, and state tests by April 20, 1944 (pilot A. Proshakov). The Yak-9U turned out to be the last of Yakovlev's aircraft built in wartime in a large series.

A total of 3921 Yak-9U aircraft of mixed design were produced (from April 1944 to August 1945).

This aircraft was unfinished, and only the great confidence of the leader in A. Yakovlev or the outright falsification of the real combat capability of the fighter when reporting to the leader can explain the fact that this fighter was launched into mass production in such a hasty manner. In state tests, an experimental Yak-9U with a VK-107A engine showed a speed of 600 km / h near the ground, and even 700 km / h at an altitude of 5600 m. But these values ​​​​were achieved on a specially prepared machine without ammunition and some of the necessary equipment. And the Yakovlev Design Bureau knew how to lighten their aircraft, so these data cannot be considered either objective or creditable.

On the other hand, the designer could report to the leader that his new aircraft was the fastest of all domestic fighters, that it was easy to fly and accessible to medium-skilled pilots, well, just a miracle, and nothing more. And although the aircraft was put into production almost immediately, in fact it was not suitable not only for combat, but also simply for flight operation, especially in the summer. Almost all fighters of the first releases could not be used for their intended purpose at all, because. the engine "spit" oil from the breather and the front seal of the gearbox shaft; oil pressure during climb fell below the permissible limit, at reduced engine operating modes, when dumping and giving gas, the plane shook, candles failed, etc., etc. And most importantly - in the summer the engine was very hot, even at nominal operation. At the same time, the speed near the ground dropped by 25 km / h, and when climbing - in general by 65 km / h; the rate of climb and climb during a combat turn turned out to be much smaller.

Since December 1944, that is, eight months after the start of production, radiators of types 728 and 726 were installed on the aircraft, the sections of the radiator tunnels were increased (up to 300 mm at the inlet and up to 100 mm at the inlet). The aerodynamics were significantly improved, the aircraft body began to be polished during manufacture. In this form, the aircraft became serviceable. Its speed reached 575 km / h near the ground, and 672 km / h at an altitude of 5000 m, i.e. almost equal to the La-7 with three guns.

The Yak-9U aircraft manufactured by plant No. 82, in the amount of 32 units, passed military tests for combat use in the Sedlets Red Banner IAP 336 of the Kovel Red Banner NAD (commander - Lieutenant Colonel V. Ukhanov) from October 25 to December 25, 1944. The aircraft made 398 sorties with a total flight time of 299 hours, i.e. around 9.5 o'clock. to the car. 26 battles were fought, 28 victories were announced (one Bf-109G2 was shot down, but there were no such fighters in the Luftwaffe combat units at all in December 1944, and 27 FW-190A (inaccuracies in determining the type of destroyed aircraft are characteristic of almost all wartime reports), losses - seven aircraft, of which non-combat - four, i.e. the majority estimates of the command and flight personnel were good and excellent, and the war, fortunately, was ending.

Yak-9UT is a serial cannon modification of the Yak-9U with serial numbers from 39 to 083, similar to the Yak-9 - Yak-9T. But here all three types of weapons were replaced. Instead of the ShVAK cannon, a lightweight NS-37 with 30 rounds and two synchronous B-20S 20 mm calibers with 120 rounds each were installed. It was possible to replace the "main caliber" guns with other options. In terms of its flight and flight characteristics, this "large-caliber aircraft" did not differ so much from the base model as the Yak-9T, and had an acceptable operating temperature. When firing, this more massive machine made it possible to fire four or five shots from the NS-37, which increased the likelihood of hitting a target. The reference aircraft was released in February 1945 in accordance with the GKO decree of February 29, 1945 and passed state tests from March 8 to March 29, 1945 (pilot A. Manucharov). The research institute was tested until July 9, 1945 and was recommended for adoption. However, in the series it was built with the NS-23 instead of the NS-37 and was built in this variant in the amount of 282 units. from February to May 1945.

Other modifications Yak-9, Yak-9UV and Yak-9P with VK-107A engine and metal wing were post-war machines. The first, training, was not launched into the series and existed in one copy, had the same habit of overheating, like other aircraft of early releases. And the Yak-9P at the beginning of the jet era became a fighter of the Soviet Air Force. Two years spent on fine-tuning the Yak-9U have not changed anything, because. this fighter had grown old before he was born. The era of piston fighters was ending. Piston Yak-9U still fought in Korea, but they were not the main characters in this conflict.

Summing up, we can conclude: the Yak-9 fighter (Yak-1, Yak-3, Yak-7) has never been the best fighter in the world. The Yak-9 was also not the best among domestic single-engine fighters. The objective reasons for the large-scale production of this front-line fighter were its cheapness and ease of production, as well as the ease of mastering by pilots of low and medium qualifications. This made it possible to quickly replenish losses and ensure multiple numerical superiority at the final stage of the war. This fighter was inferior in the second half of 1944 - 1945 in terms of combat and operational qualities, at altitudes of 3500-4500 m, to almost all the main large-scale combat fighters of both the enemy and the allies.

The Yak-9 was superior to the main fighter aircraft of other countries when maneuvering in a horizontal plane, and up to altitudes of 4500-5000 m and in rate of climb (some modifications in vertical maneuver), yielding to later types in diving speed, the effectiveness of airborne weapons, and ammunition.

The reason for this was the archaic mixed construction. The Yak-9 fighters suffered the greatest losses among large-scale single-engine fighters of the anti-Hitler coalition. However, the contribution of aircraft of this type to gaining air superiority and, ultimately, to victory in the Great Patriotic War is the largest! The Yak-9 aircraft significantly surpassed the Yak-3 fighter in safety margin and operational life, as well as in combat survivability, yielding to it in flight characteristics.

Photo	Description
	Drawing Yak-9u with VK-107A engine
	The Yak-9U is the last version which was at war. It is one of «green» Yak-9U fitted with small oil cooler wingroot intakes, narrow section, water cooler and as wing tips, as Yak-9M had. Furthermore, there isn't bullet-proof windscreen. The aircraft was adopt to serial production in a hurry. So despite high flight performance of experimental specimens the fighter considered as unreliable in combat regiments.
	Yak-9UT on factory tests. In the last weeks of the war, one of the units re-equipped with the Yak-9UT destroyed 28 enemy aircraft in 19 air battles, including 27 FW-190A-8 and 1 Me-109G-6, losing only two of its aircraft.

• "Yak-9: Private soldiers of heavens" /Dmitriy Leipnik/
• "The history of designs of planes in USSR 1938-1950" /Vadim Shavrov/
• "Planes of Stalin falcons" /Konstantin Kosminkov and Dmitriy Grinyuk/
• "Stories of the aircraft designer" /Alexander Yakovlev/
• "The Soviet planes" /Alexander Yakovlev/