At the time of the German attack on the USSR, our aviation was armed with two types of aircraft guns: 20-mm ShVAK (Shpitalny-Vladimirova large-caliber aviation), the design of which was in many respects similar to the 7, 62-mm ShKAS aircraft machine gun and 23-mm. VYa (Volkova-Yartseva).
The 20-mm ShVAK cannon was produced in the following variants: wing, turret and motor-gun. The weight of the guns is 40 kg - 44.5 kg. Rate of fire 700-800 rds / min. The initial speed is 815 m / s. Synchronous and wing-mounted 20-mm ShVAK mounts were installed on the I-153P, I-16, Yak-1, Yak-3, Yak-7B, LaGG-3, La-5, La-7, Pe-3 fighters, and in 1943 158 guns were produced for installation on Hurricane fighters instead of 7, 92-mm Browning machine guns. Two stationary guns were placed on the Tu-2 bomber and on part of the Pe-2 bombers. Defensive turrets with 20-mm ShVAK cannons were installed on Pe-8 and Er-2 bombers.
The ShVAK was superior in all respects to the German MG-FF aircraft cannon, which in 1941 was the most common in German aviation.
In 1940, designers A. A. Volkov and S. A. Yartsev created a 23-mm automatic cannon VYa-23 for a new 23-mm cartridge. Weighing 66 kg, the gun did 550-650 shots / min.
In the VYa cannon, shells weighing 200 grams were used, which is twice as much as that of the ShVAK. An armor-piercing incendiary projectile at a distance of 400 m along the normal pierced 25-mm armor.
The recoil of the VYa cannon was large enough, and it was not originally installed on fighters. By the beginning of the war, its only carrier was the Il-2 attack aircraft, in each wing of which one VYa cannon was installed with an ammunition load of 150 rounds per barrel. Later, she was armed with Il-10 attack aircraft and partially LaGG-3 fighters.
In the course of hostilities, it turned out that Soviet aircraft guns of 20-23 mm caliber were able to effectively fight only against light armored vehicles of the enemy, medium tanks and self-propelled guns were too tough for them.
In the second half of 1942, a small series of the Il-2 version was released, armed with 37-mm ShFK-37 cannons.
The 37-mm ShFK-37 aircraft cannon was developed under the leadership of B. G. Shpitalny.
The weight of the gun mounted on the Il-2 aircraft was 302.5 kg. The rate of fire of the ShFK-37, according to field tests, averaged 169 rounds per minute with an initial projectile speed of about 894 m / s. The gun ammunition included armor-piercing incendiary tracer (BZT-37) and fragmentation-incendiary-tracer (OZT-37) shells.
The BZT-37 projectile provided penetration of German tank armor 30 mm thick at an angle of 45 degrees. to the normal from a distance of no more than 500 m. Armor thickness 15-16 mm and less, the projectile pierced at meeting angles of no more than 60 degrees. at the same distances. Armor 50 mm thick (frontal part of the hull and turret of medium German tanks) was penetrated by the BZT-37 projectile from distances of no more than 200 m at meeting angles not exceeding 5 degrees.
Large overall dimensions of the ShFK-37 cannons and store food (magazine capacity of 40 rounds) determined their placement in fairings under the wing of the Il-2 aircraft. Due to the installation of a large magazine on the cannon, it had to be lowered strongly relative to the wing construction plane (aircraft axis), which not only complicated the design of attaching the cannon to the wing (the gun was mounted on a shock absorber and moved with the magazine when firing), but also required it to be done for her fairings bulky with a large cross-section.
The tests showed that the flight performance of the IL-2 with the ShFK-37 large-caliber air cannons, compared to the serial IL-2 with the ShVAK or VYa cannons, significantly decreased. The aircraft has become more inert and more difficult to fly, especially in turns and turns at low altitude. Maneuverability deteriorated at high speeds. The pilots complained about significant loads on the rudders when performing maneuvers.
Aimed firing from the ShFK-37 cannons on the Il-2 aircraft was largely difficult due to the strong recoil of the guns when firing and the lack of synchronization in their work. Due to the large spacing of the guns relative to the center of mass of the aircraft, as well as due to the insufficient rigidity of the mount of the gun mount, it led to the fact that the attack aircraft experienced strong shocks, "pecks" during firing and strayed from the aiming line, and this, in turn, taking into account the insufficient longitudinal stability "Ila", led to significant dispersion of shells and a sharp decrease (about 4 times) in the accuracy of fire.
Shooting from one cannon was completely impossible. The attack aircraft immediately turned towards the firing cannon so that it was not possible to introduce an amendment to the aiming. In this case, hitting the target could only be the first projectile.
During the entire test period, the ShFK-37 guns worked unreliable - the average percentage of ammunition shot per failure was only 54%. That is, almost every second sortie on an Il-2 combat mission with ShFK-37 cannons was accompanied by the refusal of at least one of the cannons. The maximum bomb load of the attack aircraft decreased and was only 200 kg. All this significantly reduced the combat value of the new attack aircraft.
Despite the failure with the ShFK-37, work in this direction was continued. In 1943, the production of the NS-37 air cannon began (designers Nudelman and Suranov). It used tape feed, which made it possible to increase the rate of fire to 240-260 rds / min. The muzzle velocity of the projectile is 810 m / s, the weight of the gun is 171 kg. Thanks to the belt feed and lower weight, it became possible to install the new system on fighters.
Military tests of the gun were carried out on the LaGG-3 from April 21 to June 7, 1943 on the Kalinin Front and on the Yak-9T from July 22 to August 21, 1943 on the Central Front. After military trials, the gun was put into service under the designation NS-37. The Yak-9T (tank) aircraft was produced from March 1943 to June 1945. A total of 2,748 aircraft were produced.
As conceived by the designers, an increase in the firepower of fighters was supposed to increase the range of aimed firing and the likelihood of hitting a target. In order to shoot down a fighter, as a rule, one hit from a 37-mm projectile was enough; for a twin-engine bomber, two or three were required.
However, the new cannon also had disadvantages. The increase in caliber reduced the rate of fire and the number of rounds in ammunition on board the fighter. Effective shooting at aerial targets was only single projectiles, since when firing from a Yak-9 aircraft, the plane swayed strongly, and aimed fire was obtained only with the first shot, with subsequent shells scattered. It is worth noting the absence of high-quality sights on most Soviet fighters built during the war, as a rule, it was the simplest "Vizir Vasiliev" consisting of rings painted on the windshield and a front sight, this of course affected the effectiveness of shooting at medium and long distances.
On July 20, 1943, military tests of the Il-2 with two 37-mm NS-37 air cannons began, which continued until December 16. In total, 96 Il-2 attack aircraft with NS-37 were involved in military trials.
Compared to the serial Ilami, armed with ShVAK or VYa cannons, the Il-2 with the NS-37 and with a bomb load of 200 kg has become more inert, more difficult on a bend and on a combat turn.
The deterioration of the aerobatic characteristics of the new attack aircraft, like the IL-2 with the ShFK-37 cannons, was associated with a large mass spread over the wingspan and the presence of cannon fairings, which worsen the aircraft aerodynamics. The IL-2 with NS-37 did not have longitudinal stability over the entire centering range, which significantly reduced the accuracy of firing in the air. The latter was aggravated by the strong recoil of the guns when firing from them.
Tests have shown that firing from an Il-2 aircraft from NS-37 cannons should only be fired in short bursts of no more than two or three shots in length, since when firing simultaneously from two cannons due to the asynchronous operation of the aircraft, the aircraft experienced significant pecks and was knocked off the aiming line. Aiming correction in this case was basically impossible.
When firing from one cannon, hitting the target was possible only with the first shot, since the attack aircraft turned towards the firing cannon and the aiming correction became impossible. The defeat of point targets - tanks, armored vehicles, cars, etc. with normal operation of the cannons was quite achievable.
At the same time, hits on tanks were received only in 43% of sorties, and the number of hits to the spent ammunition was 2.98%.
According to the general opinion, the flight personnel flying the IL-2 from the NS-37, the attack aircraft, when attacking small targets, had no advantages over the IL-2 with smaller caliber guns (ShVAK or VYa) with a normal bomb load of 400 kg. At the same time, the use of IL-2 with NS-37 for large area and volumetric targets, ammunition depots, accumulations of tanks, artillery and anti-aircraft batteries, railway trains, small vessels, etc., could be quite successful.
When operating against ground targets, the effectiveness of each type of gun is determined by the nature of the target. So, when firing at openly located live targets, the action of a 7, 62-mm bullet differed little from the action of a 20-mm projectile, since their fragmentation effect is very weak and a direct hit was required to defeat personnel. When firing at cars, railway stations and small craft, 7, 62-12, 7-mm machine guns were ineffective, and the effect of aircraft cannons increased sharply with an increase in the caliber and weight of the projectile. Here, guns of a larger caliber were just needed.
Massive destruction of tanks from aircraft cannons, widely advertised in films and memoirs, in most cases refers to hunting stories. It is simply impossible to penetrate the vertical armor of a medium or heavy tank with a 20mm - 37mm aircraft cannon. We can only talk about the armor of the tank's roof, which is several times thinner than the vertical one and was 15-20 mm for medium tanks and 30-40 mm for heavy tanks. Aircraft guns used both caliber and sub-caliber armor-piercing shells. In both cases, they did not contain explosives, but only occasionally a few grams of incendiary substances. In this case, the projectile had to hit perpendicular to the armor. It is clear that in combat conditions, the shells hit the roof of the tanks at much smaller angles, which sharply reduced their armor penetration or even ricocheted. To this it must be added that not every shell that pierced the armor of a tank put it out of action.
Taking into account the decrease in flight characteristics and the decrease in the bomb load on the Il-2 aircraft armed with the NS-37, this modification of the attack aircraft was not widespread. The PTAB-2, 5-1, 5 cumulative bombs, which entered service in 1943, turned out to be a much more effective anti-tank weapon.
On the basis of the NS-37 cannon, while maintaining the overall dimensions, an aviation, automatic 45-mm NS-45 cannon was created. The weight of the gun was 150-153 kg. Rate of fire 260-280 rds / min. The cannon is supplied with a belt feed. In the 45-mm aircraft cannon NS-45, for the first time in the USSR, a muzzle brake was used on an aircraft, absorbing up to 85% of the recoil energy. In 1944-45, a total of about 200 guns were produced. The Yak-9K (large-caliber) fighter with the NS-45 cannon in the engine collapse, with 29 rounds of ammunition was specially designed and built for this gun. A total of 53 aircraft of this type were manufactured.
44 Yak-9K aircraft underwent military trials from August 13 to September 18, 1944 at the 3rd Belorussian Front and from January 15 to February 15, 1945 at the 2nd Belorussian Front. It was assumed that fighters with large-caliber cannons would act on groups of enemy bombers, being outside the effective defensive fire zone of their firing points. On average, ten 45-mm shells were spent on one downed enemy aircraft.
However, the Yak-9K themselves needed cover for fighters with 20-mm cannons, including driven machines. Aimed firing from 45-mm cannons was obtained only on the first shot, the rest of the shells flew past. After a burst of three shots, fired even at maximum speed, the latter fell sharply, the stability of the aircraft was lost, oil and water leakage in the pipelines was observed.
In addition, it was very rare to meet a large group of enemy bombers at the end of 1944, and there was no particular need for such a fighter. According to the results of military tests, the Yak-9K was not launched into mass production.
In the USSR, in wartime, aircraft cannons and larger calibers were developed. The 57-mm automatic gun N-57 was developed under the leadership of the leading designer G. A. Zhirnykh at the end of the Great Patriotic War. For this caliber, the gun had a relatively small mass - 135 kg. A small series of 36 guns was made.
The gun was successfully tested on the MiG-9 "F-3" jet fighter (third prototype). This was the first and only case in the history of aviation that a 57-mm cannon was mounted on a jet fighter. But the production of the MiG-9 was launched with the 37 mm N-37 cannon, although some of the aircraft of the first batch were still equipped with the N-57 cannon. Subsequently, on all aircraft, it was replaced by the N-37 cannon.
In 1943-1945. at the TsAKB which was headed by V. G. Grabin, work was underway to create large-caliber aviation automatic cannons.
65-mm, 76-mm, 100-mm automatic aircraft guns were developed.
In 1948, two prototypes of the 65-mm cannon were manufactured and factory tested. In 1949, one sample was sent for field tests at the Air Force Research Institute. For the 65-mm gun, two shots were created: with an OFZT projectile and with an BRZT projectile. At a distance of 600 m, the BRZT projectile pierced 60 mm of armor at a meeting angle of 30 °. Thus, this projectile could penetrate the armor of any tank of that time from above.
In 1948, TsNII-58 began work on the B-0902 100-mm automatic aviation cannon. It was supposed to be installed on Tu-2 and Tu-4 bombers, which were going to be converted into fighters. Naturally, neither propeller-driven (Yak-3, JIa-5, La-7, La-9, etc.) nor jet (Yak-15, MiG-9, etc.) fighters could physically carry this gun because of its weight and impact.
The automatic equipment of the 100-mm cannon was of a mechanical type with a long barrel stroke, and all operations were carried out automatically. The gun was equipped with a powerful muzzle brake that absorbed 65% of the recoil energy. The cannon was made compact due to the rational placement of all its units. Store food tapeless. The store held 15 unitary cartridges.
The gun fire and pneumatic reloading were controlled from the cockpit. The weight of the gun without the power box was 1350 kg. Rate of fire - 30.5 rounds per minute. Recoil force - 5 tons.
For the V-0902 cannon, the TsNII-58 specially created three shots: with the FZT projectile, with the BRZT projectile and with a remote grenade.
The cartridge with the FZT projectile (high-explosive incendiary tracer) had a weight of 27 kg and a length of 990 mm. The weight of the propellant charge was 4.47 kg, due to which the projectile had an initial velocity of 810 m / s. The shell itself, weighing 13.9 kg, contained 1.46 kg of explosives. The effective firing range of the FZT projectile was 1000-1200 m.
The cartridge with the BRZT projectile had a weight of 27, 34 kg and a length of 956 mm. The propellant weight was 4.55 kg, and the projectile received an initial velocity of 800 m / s. The shell itself, weighing 14.2 kg, contained a little explosive (0.1 kg). During test firing, the BZRT projectile pierced 120-mm armor at a distance of 600 m (at a meeting angle of 30 °).
For firing at aerial targets, a 100-mm remote grenade with lethal incendiary elements was created. The weight of the grenade is 15.6 kg. The grenade contained 0, 605 kg of explosive (expelling charge) and 93 lethal-incendiary elements weighing from 52 to 61 g each. The projectile was equipped with a VM-30 remote tube. In 1948-1949. Experimental batches of grenades with unitary and annular arrangement of lethal incendiary elements were tested. To test the effectiveness of the fragments and their "incendiary ability", ground firing was carried out at the aircraft.
The 100-mm B-0902 cannon became the most powerful automatic aircraft cannon not only in the USSR, but also, apparently, in the world. From a technical point of view, it was a masterpiece of engineering. The only trouble is that she was five years late. In 1944-1945. a high-speed bomber with a piston engine could shoot from it with almost impunity the flying fortresses B-17 and B-29 flying in dense order from a distance of 1 km or more. But the advent of jet fighters radically changed the tactics of air combat, and heavy aircraft cannons lost all meaning, at least for firing at aircraft.
