Fighter First flight: 1943 Yakovlev

The Yak-9P (cannon) with the M-105PF engine was the result of another attempt to increase the power of the Yak-9 onboard weapons, in this case by installing a second ShVAK cannon instead of the UBS synchronous machine gun. Let us recall that it was precisely such weapons that were on the La-5 fighters, and the pilots' reviews of the Lavochkin's firepower were more favorable. The ammunition load of the second gun was 165 shells (instead of 200 UBS rounds), and the second salvo increased 1.25 times compared to the standard armament of the Yak-9. In terms of flight and tactical characteristics, piloting technique, stability and controllability, as well as takeoff and landing properties, the Yak-9P practically did not differ from the Yak-9, but aiming was disrupted when firing in bursts, especially if the speed at the moment of opening fire was not high enough, therefore when shooting, it was necessary to clarify the aiming all the time.

The Yak-9P was built at the Design Bureau in March 1943 and underwent state tests at the Air Force Research Institute from March 17 to April 8, 1943 (pilot A. Proshakov, lead engineer G. Sedov). The assessment was generally positive, but they refrained from serial construction due to the difficulties that arose during the shooting. However, the experience of installing the second gun could be used to create more advanced Yak-9 TK vehicles with the M-105PF engine. An attempt to strengthen the Yakov's armament was also the idea of ​​making the plane transformable for various guns. It was about the possibility of equipping the Yaki with various guns directly in the combat units, with the available forces of the technical staff, depending on the needs. The installation of the guns, according to the developers, was to be carried out in the field, provided there was an appropriate set of weapons and fasteners to it (MP-20 and MP-37). We add that in order to install a new weapon, it was necessary to replace the gas outlet pipes, as well as all the power supply units for the weapon (cartridge boxes, sleeve and link outlets, etc.) And also the hoses of the pneumatic systems ... It was assumed that in addition to the standard gun, in this way it would be possible to mount VYa-23 (23 mm), NS-37 and even NS-45.

The following weapon options were envisaged:

20, 23, 37 mm cannon firing through the propeller hub (ammunition load, respectively, 120, 80 and 30 rounds) and two synchronous 20 mm cannons (120 rounds per barrel)

45 mm cannon (20 rounds) and two synchronous 20 mm cannons (120 rounds each).

57 mm cannon and one synchronous cannon with 120 rounds.

One experienced Yak-9TK with replaceable motor-guns was created and presented for testing at the Air Force Research Institute in October 1943. Tests have shown that the VYa-23 in terms of power does not differ much from the standard ShVAK, and the NS-45 turned out to be not entirely reliable. With the NS-37 cannon, the Yak-9T was serially built. So this unattractive "transformer" was not included in the series. In the Luftwaffe, this problem was solved in this way. For the Bf-109F and G fighter of all modifications, special field installation kits could be installed on the wing suspension assemblies. They consisted of different guns of caliber from 15 to 30 mm, each was enclosed in underwing gondolas together with a sleeve and ammunition, and very quickly, after connecting the electric trigger terminals, it became ready for battle. It was not possible to simply copy the German system due to the weakness of the wing, and the guns did not differ in compactness, especially those that were more powerful.

The last aircraft ( Yak-9K with a VK-105PF engine ) in this direction was a fighter with a 45-mm cannon built in late 1943 - early 1944. During the war years, only Yakovlev could decide to arm fighters with such heavy weapons, especially such as the Yak-9K. Moreover, he managed to achieve the construction of a military series of 53 Yak-9K in April-June 1944. The NS-45 cannon was installed in the collapse of the cylinders of a conventional VK-105PF and was attached to the fuselage at three points - two front from one rear, for firing through the hollow shaft of the gearbox. A special device with a ball bearing was installed on the screw hub, centering the gun barrel relative to the shaft, because the gap between it and the gun barrel was only 0.75 mm. The recoil force was very strong. Such a load could simply destroy the plane. To prevent this from happening, for the first time in the history of domestic fighter aircraft, the barrel was equipped with a powerful muzzle brake that extinguished more than 2/3 of the recoil. The barrel with a muzzle brake protruded from the propeller by 370 mm, slightly increasing the longitudinal dimension of the fighter. The cannon was fed by a belt feed. The capacity of the cannon's cartridge box is 29 rounds. Sleeves and links were collected in a special collection. For the first time in the history of Soviet aircraft construction, a counter for the remaining ammunition load of the gun was installed on the dashboard in the cockpit. Fire control was carried out by a pneumatic-electrical system. Shooting from a cannon and a machine gun could be conducted separately and simultaneously from two electro buttons on the control handle. The sight was PBP-1a.

The aircraft also had a number of other improvements, of which the armored glass in the front of the visor and behind the pilot's head should be noted first of all. The flight weight of the fighter reached 3028 kg. In terms of the mass of a second salvo of 5.53 kg / s, the Yak-9K surpassed all domestic and foreign single-engine fighters (without outboard armament) with motor-guns, but was inferior in the second salvo of the FW-190A-6 (7.02 kg / s) (1943 g.), FW-190A-7, A-8, A-9 (7.69 kg / s) (1942-1945) * and other later foreign fighters. The speed dropped by 27-40 km / h, and the climb time of 5000 m increased to 6.8 minutes. It was possible to shoot only in very short bursts, in 1-3 shells at a speed of over 350 km / h. And the feeling was eerie. The plane "for a moment seemed to stop in the air, shuddering terribly from the hood to the tips of the wings." When firing at a lower speed, the Yak sharply turned back and sideways, the belts cut into the pilot's shoulders and then threw back onto the seat, and the pilot often hit the back of his head against the bulletproof glass (there was no soft headrest, like on Spitfires or BM09G-6, on the Yak) ... But the main thing is that the large recoil force had a significant effect on the design of the aircraft, leading to the leakage of oil and water through various seals and the appearance of cracks in pipelines, radiators, etc.

Feedback from combat pilots about this aircraft, however, was not bad. In combat units, the aircraft was used as cover for the wingman, who usually flew on the Yak-3 or Yak-1B and was supposed to protect the leader, who “took off the bombers,” sometimes from a distance of 400-600 m. The weapon of this Yak was very effective for ground operations. targets, allowing you to destroy a boat, car or artillery gun with one go. These aircraft were also used to actively block airfields at the final stage of the war. Several vehicles "survived" to participate in the Berlin operation. No wonder. The "flying cannon" was, as a rule, trusted by real air snipers, many of whom flew the Yak-9T with the NS-37 and had considerable combat experience in the use of Soviet large-caliber weapons.

Photo	Description
	Drawing Yak-9P
	Drawing Yak-9K
	Yak-9K during tests at the Air Force Research Institute. The barrel of the cannon with a muzzle brake protruded from the propeller by 370 mm

• "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/