Unknown aircraft machine gun Degtyarev
In the comments to the publication “Service and combat use of captured German machine guns after the end of World War II” one of the regular visitors to the Military Review website asked me to tell you in more detail about the Soviet aircraft machine gun YES, and I promised to do so. Aviation Degtyarev's machine gun, of course, is known to aviation enthusiasts and military experts stories, but the general reader is not so familiar with it.
The creation of the YES aircraft machine gun, the prerequisites for its appearance and design features
After the end of the Civil War in the Workers 'and Peasants' Red Air Force navy there was a huge variety of aircraft machine guns for various ammunition. Soviet combat aircraft at that time used machine guns: Lewis, Vickers, Hotchkiss and Colt.
In the 1920s, the outstanding domestic gunsmith V. G. Fedorov and his assistant and student V. A. Degtyarev, as part of the small arms unification program weapons On the basis of one model in the mid-1920s, work was carried out to create a single machine gun complex chambered for the Japanese 6,5x50 SR cartridge.
Single 6,5 mm Fedorov-Degtyarev machine gun on an anti-aircraft rack
In addition to samples intended for use in infantry and armored vehicles, the tandem of designers carried out work on the creation of aircraft machine guns, and also designed twin and triple installations.
6,5 mm triple aircraft machine gun Fedorov-Degtyarev
For a number of reasons, including due to the use of an insufficiently powerful Japanese cartridge, the Fedorov-Degtyarev machine gun complex was not accepted for service. But the experience gained and some developments subsequently found practical application in other samples. Thus, the DP light machine gun used the design of disk magazines developed for experimental 6,5 mm machine guns.
The DP machine gun is often criticized for its bulky and heavy disk magazine. But it was chosen after many experiments with sector magazines, tested on experimental 7,62 mm machine guns. In sector magazines, the flanges of the Mosin welt cartridge tended to cling to each other, which made such a power supply scheme unreliable.
After finalizing a number of experimental models, V. A. Degtyarev in the fall of 1926 introduced a light machine gun chambered for 7,62x54 R. The automatic machine gun worked by removing part of the powder gases through a side hole. The hole was made in the barrel wall at a distance of 185 mm from the muzzle. Long stroke gas piston. Open type gas chamber with pipe. The piston rod, rigidly connected to the bolt frame, and the return spring, mounted on the rod, were placed under the barrel in the guide tube.
A gas piston screwed onto the front end of the rod fixed the return spring. Using a pipe regulator having two gas outlet holes with a diameter of 3 and 4 millimeters, the amount of discharged powder gases was adjusted.
The barrel bore was locked using a pair of lugs mounted on the sides of the bolt on hinges and moved apart by the extended rear part of the firing pin. The trigger mechanism consisted of a trigger, a trigger lever with a sear, and an automatic safety. The trigger was supported by a safety at the rear. To turn it off, you need to completely cover the neck of the butt with your palm. The fire mode is continuous only.
Due to the fact that the machine gun was originally designed for intense burst fire and significant heating, the shot was fired from the rear sear or, in other words, from an open bolt. The bolt carrier with the bolt was in the rear position before the first shot, held by the sear. When the trigger was pressed, the trigger lever dropped, the bolt frame broke off the sear and moved forward, pushing the bolt and firing pin with its vertical stand.
The bolt captured the cartridge from the receiver and sent it into the chamber, resting against the stump of the barrel. During further movement of the bolt frame, the firing pin moved the lugs apart with its widened part, the supporting planes of the lugs entered the lugs of the receiver.
After locking, the firing pin and bolt frame continued to move forward for another 8 mm, the firing pin reached the cartridge primer, breaking it and firing. After the bullet passed through the gas outlet holes, the powder gases that entered through the gas outlet holes acted on the piston, which covered the chamber with its bell, and threw back the bolt frame.
Then the firing pin passed through the frame approximately 8 mm, released the lugs, and the lugs were brought together by the bevels of the frame's figured recess, then the barrel bore was unlocked, the bolt was picked up by the bolt frame and pulled back. In this case, the ejector removed the spent cartridge case, which, hitting the firing pin, was thrown out through the receiver window in the lower part.
After this, the bolt frame hit the trigger frame and moved forward under the action of the return spring. If at this moment the trigger was pressed, the automation cycle was repeated. If the trigger was released, the bolt frame stood on the sear with its cocking mechanism, stopping in the rear position.
The magazine, mounted on top of the receiver, consisted of a pair of disks and a spring. The cartridges in the store were placed along a radius with the toe of the bullet towards the center. By the force of a snail-shaped spiral spring, which twisted when the magazine was loaded, the upper disk rotated relative to the lower one, while cartridges were fed to the receiver window.
It was initially assumed that the power system would have 50 rounds, and in order to maintain the dimensions of the finished disk magazine, designed for fifty 6,5 mm rounds, its capacity was reduced by one round.
But the magazine capacity was soon reduced to 47 rounds because the spring force was not enough to reliably feed the last rounds. However, during operation, due to the weakening of the feed spring, machine gunners at the front often did not fully equip the magazines.
Experienced Degtyarev light machine gun
After finishing development, two copies of the light machine gun were tested by the commission of the Artkom of the Artillery Directorate of the Red Army at the Kovrov plant on January 17–21, 1927. The machine guns were found to have passed the tests and were recommended for adoption after the defects were corrected. Without waiting for the results of the improvements, the Kovrov plant received an order for 100 machine guns, for which on March 26 Artcom approved the “Temporary Specifications for the acceptance of the Degtyarev light machine gun.” The customer signed the acceptance certificate for the entire batch on January 3, 1928.
In 1928, the machine gun passed military tests, as a result of which it received a flame arrester and a modified gas chamber regulator pipe. At the end of 1928, the machine gun was put into service under the designation “7,62-mm light machine gun mod. 1927." or DP (“Degtyareva, infantry”). At the same time, they decided to curtail the serial production of the MT (Maxima-Tokarev) light machine gun.
Serial DP
It must be said that the DP was structurally very simple and consisted of 68 parts. For comparison: the American Browning M1922 BAR had 125 parts, and the Czech ZB-26 had 143 parts.
Even before the DP was adopted, the designer began work on designing samples intended for use on armored vehicles and aviation.
Field tests of the aviation version of the Degtyarev machine gun took place from December 1927 to February 1928. In 1928, simultaneously with the PV-1 machine gun designed by A.V. Nadashkevich, created on the basis of the Maxim heavy machine gun and intended for use in offensive fixed installations, the DA turret aviation machine gun (Degtyareva, aviation) was adopted by the Red Army Air Force ).
In order to increase the practical rate of fire, the DA machine gun was equipped with a new disk magazine with an initial capacity of 65 rounds, in which the cartridges were arranged in three tiers. Later, for more reliable operation, its capacity was reduced to 63 rounds. The magazine was equipped with a belt handle on top, which made replacing it easier and faster.
For ease of aiming at fast-moving targets, the machine gun instead of a butt received a rear handle, a pistol grip and new sighting devices with a weather vane front sight that took into account the aircraft’s own speed, which made it possible to shoot more accurately. A faceplate was screwed to the front of the receiver. A kingpin was attached to its lower part, which had a curved swivel for installation on the turret. A sleeve with a ring sight was attached to the front top. Since the casing was removed and the faceplate was installed, changes were made to the fastening of the gas piston guide tube.
An unexpected problem when fine-tuning the aircraft machine gun was the collection of spent cartridges, which, scattering inside the aircraft, could create the preconditions for flight accidents. For a long time it was not possible to avoid spent cartridges becoming jammed in the neck of the collection bag when it was partially filled. It was possible to eliminate this drawback after studying high-speed filming frames by creating a profiled entrance to the bag corresponding to the trajectory of the cartridge cases.
At the time of its appearance, the DA machine gun, intended for use in defensive installations, was fully suitable for its purpose. It was quite light, which is important for use in aviation. The weight of the weapon without a magazine was 7,1 kg, with a loaded magazine - 11,5 kg. Length – 940 mm. Rate of fire – 600 rounds/min.
The ballistics of the DA corresponded to the infantry DP and tank DT. The initial speed of a “light” bullet with a steel core was 840 m/s. When firing at air targets, the most effective were cartridges with armor-piercing incendiary-tracer, armor-piercing incendiary and sighting-incendiary bullets. When repelling attacks from fast-moving fighters, targeted shooting was possible at a distance of up to 400 m.
The rate of production of the DA was quite high; as of March 30, 1930, Air Force units had 1 machine guns. Another 200 copies were being prepared for acceptance by military representatives. The rapid development of DA machine guns was facilitated by the interchangeability of parts with the DP machine gun, which was widespread among the troops.
Soon after the adoption of the DA machine gun, due to the increase in the flight speed of combat aircraft, the military announced the need to increase the rate of fire, and in 1930 the DA-2 twin turret unit entered service. To be fair, it must be said that the development of the DA-2 was ordered back in 1927.
DA-2 in the Museum of Artillery, Engineering and Signal Corps
On the twin, each machine gun had a front mounting coupling. The side bosses of the couplings were used for fixation on the installation, and the bottom bosses were used to hold the gas piston tube. The rear mounting of the machine guns on the installation were coupling bolts that passed through holes made in the rear bosses of the receiver. The machine guns were connected to the turret through a pin. The general trigger hook was installed on the pistol grip of the right machine gun in an additional trigger guard.
On the left machine gun, for ease of use, the safety box and bolt handle were moved to the left side, and a bracket for a weather vane front sight was installed on its barrel. Since the total recoil of coaxial machine guns became greater, active muzzle brakes were installed on the barrels. Later, a brake of this design was used on the 12,7 mm DShK machine gun. The unit was equipped with a chinrest, shoulder or chest rest.
The weight of the DA-2 with loaded magazines and front sight was 26 kg, length - 1 mm, width - 140 mm, distance between the axes of the barrel channels - 300 mm.
Service and combat use of aircraft machine guns DA and DA-2
In 1932, the DA-2 replaced the DA in production. In 1935, due to the advent of a much faster 7,62-mm ShKAS machine gun (firing rate up to 1 rounds/min), production of the DA-800 was discontinued. In total, the military received 2 DA machine guns and 12 DA-914 twin guns.
Twin machine gun mount DA-2 on Tur-6 turret
Single and coaxial machine guns were placed on the Tur-2, Tur-5 and Tur-6 turrets, located on the upper part of the aircraft fuselage, providing shelling of the upper hemisphere and allowing shooting from the sides downwards.
The structural basis of the turret consisted of two rings, while the fixed ring was attached to the fuselage. The shooter was located inside the rings, in the open air flow. An arc was hinged on the movable ring, in which a DA or DA-2 machine gun was mounted on a pivot.
The shooter controlled the weapon using muscle power. To facilitate the rotation of the turret in the horizontal plane, the movable ring was connected to a spring device that compensated for the effect of the aerodynamic moment. During vertical maneuvers, the shooter was helped by rubber shock absorbers, which relieved the weight of the arc with the weapon. However, with such a system, the shooter quickly got tired: rubber-spring compensators countered the effect of the air flow only at a strictly defined flight speed.
Until the end of the 2s, the DA and DA-1930 machine guns were actively used on the R-3 and R-5, R-6 reconnaissance aircraft, as well as on the TB-1 and TB-3 bombers. After the start of mass deliveries of ShKAS machine guns, they were first installed on new aircraft and gradually re-equipped those in service.
As of June 22, 1941, most of the DA, DA-2 and PV-1 suitable for further use were in warehouses. A certain number of DA and DA-2 aircraft machine guns remained in the troops, where they were mainly used for training purposes, and also protected the rear hemisphere of U-2 communications aircraft and R-5 reconnaissance bombers.
Defensive installation with a DA machine gun on a U-2 aircraft
After the attack by Nazi Germany, the use of Degtyarev machine guns in the Red Army Air Force continued, and primarily this concerned the relatively compact and lightweight YES. This machine gun could be quickly transferred from side to side for firing from the side windows of transport and passenger aircraft, and for which weapons powered from a disk magazine and not creating inconvenience with a hanging tape were well suited.
In the spring of 1942, a field two-seat modification of the Il-2 attack aircraft appeared, in which the rear hemisphere was protected by a shooter with a DA machine gun. The experienced Il-2bis attack aircraft with the BLUP-1 turret, which underwent combat tests on the Kalinin Front in the 6th GShAP from November 7 to December 9, 1942, had a very spacious and comfortable gunner’s cabin. Thanks to this, the shooter could additionally take the DA light machine gun into flight and fire through the side windows, repelling attacks from German fighters from the side, as well as fire at ground targets.
Il-2bis
The pilots and gunners liked the car. The radio operator's cabin was not only spacious, but also well protected. However, the Il-2bis was never put into serial production. The reason is a large number of design changes, and the bomb load of the Il-2bis was one third less than that of the single-seat Il-2.
In the initial period of the war, the Red Army experienced an acute shortage of anti-aircraft weapons designed to directly protect troops from German fighter-bombers, dive bombers and attack aircraft operating at low altitudes. This, in turn, led to unjustified losses and greatly complicated the organization of defense. Under the current conditions, it was decided to use obsolete aircraft machine guns in storage to create anti-aircraft machine gun installations.
The use of Degtyarev aircraft machine guns as anti-aircraft guns was facilitated by the fact that they were initially equipped with sights designed to fire at rapidly moving air targets, and had the appropriate controls.
DA-2 on an anti-aircraft tripod mod. 1928, designed by M. N. Kondakov
The conversion of DA and DA-2 machine guns into anti-aircraft guns was carried out in the front-line weapons workshops, and there was no single standard for such ZPU. DA machine guns, as a rule, were mounted on simple swivels, and twin DA-2s were mounted on more complex and stable turrets.
Anti-aircraft gun DA-2 with a balancing mechanism
Part of the DA-2 anti-aircraft installations was equipped with balancing mechanisms. Those that did not have such mechanisms were equipped with shoulder stops.
Despite the lack of a uniform standard and the semi-handicraft nature of the production of anti-aircraft turrets, in general it turned out to be a fairly effective and light weapon. A twin installation with two loaded magazines, mounted on a tripod machine, weighed half as much as the Maxim machine gun on an anti-aircraft machine mod. 1928 with twice the firepower. The relatively small magazine capacity compared to belt-fed anti-aircraft machine guns was partly compensated by the ability to quickly replace it.
In addition, the Degtyarev aircraft machine gun could easily digest standard rifle cartridges, and for trouble-free shooting from the ShKAS, a special cartridge with additional bullet fixation and an improved primer was required.
Despite the fact that at the final stage of the war the troops were largely saturated with domestic anti-aircraft heavy machine guns DShK and Browning M2 received under Lend-Lease, installations with DA and DA-2 machine guns remained in anti-aircraft units until the end of hostilities.
Anti-aircraft DA-2s enjoyed some popularity in the Finnish army. There were several dozen such anti-aircraft installations captured from the Red Army.
Finnish gunsmith with DA-2 anti-aircraft gun
The use of DA and DA-2 was facilitated by the fact that the standard cartridge in Finland was the Russian 7,62x54 R, and along with the Lahti-Saloranta M/26 light machine gun, the Finnish infantry very actively used Soviet DP. It is known that Degtyarev’s captured machine guns were modified, and they were equipped with an additional fuse and flame arrester of the Finnish type.
Comparison of the DA machine gun with foreign analogues
By the beginning of World War II, other countries also had many magazine-fed aircraft machine guns.
The closest in characteristics to the domestic YES is the Lewis machine gun, modified for use on aircraft.
Aviation machine gun Lewis Mk. III with 97 round disc
Without Lewis Mk. III weighed about 8 kg. The weight of the magazine with cartridges is 5,3 kg. The rate of fire of the aviation version is up to 850 rounds/min. The Lewis guns, which were in service in France, Italy and Japan, fired the standard British 0,303 (7,7 mm) cartridge.
By the second half of the 1930s, the Lewis Mk. III were used to a limited extent in aviation. The British sent most of their machine guns to warehouses. These weapons came into demand when it became clear that the British territorial defense units, hastily formed in anticipation of a German invasion, lacked anti-aircraft machine guns. As in the case of Soviet Degtyarev aircraft machine guns, several thousand Lewis guns were installed on anti-aircraft machines.
The Lewis was produced under license in Japan; the machine gun used in naval aviation was designated Type 92.
Japanese Type 92 aircraft machine gun
Without cartridges, the Japanese machine gun weighed 8,5 kg. Length – 980 mm. Rate of fire – 600 rounds/min.
Another aircraft machine gun with a disk magazine for 97 rounds attached to the top was the British Vickers Class K, produced from 1934 to 1939. In total, more than 100 thousand units were produced.
Vickers Class K aircraft machine gun on the turret of a Fairey Battle bomber
Without the disc, the Vickers Class K weighed 9,5 kg. Length – 1 mm. Rate of fire: 016–950 rounds/min.
The machine gun used automatic gas venting with a long stroke of a gas piston located under the barrel. It was possible to quickly replace the barrel. The Vickers Class K aircraft machine gun was equipped with a characteristically shaped vertical fire control handle with a trigger on the back of the receiver.
In 1940, Vickers Class K machine guns began to be transferred to air force ground units to guard airfields, where they were installed on various improvised anti-aircraft machines.
They were also used in single and twin installations by the British Navy and SAS commando units, where Vickers were mounted on SUVs and trucks.
In the early 1930s, the vz aircraft machine gun began to be produced in Czechoslovakia. 30, based on the English Vickers Mk. III. In order to provide the ability to feed from a tape and from a 50-round disk, the original sample underwent significant processing.
Czechoslovakian aircraft machine gun vz. 30 disk-fed in a light bomber defensive mount
Automation vz. 30 worked due to the short stroke of the barrel during recoil. Depending on the version, the weight of the machine gun was 11,4–11,95 kg. Length – 1 mm. The rate of fire with magazine feed is 033 rds/min, with belt feed – 950 rds/min.
Until 1938, the plant in Strakonice managed to assemble about 4 machine guns used in Czechoslovakia and exported. In particular, the party vz. 500 were sold to Greece. Taking into account the higher rate of fire than that of infantry models, some of the aircraft machine guns were used in ground-based anti-aircraft installations, which were intended to provide air defense for airfields.
In 1936, the MG machine gun officially entered service with the Luftwaffe. 15 (before adoption it had the index Rheinmetall T.6-200), designed on the basis of the MG light machine gun. 30, which in turn was descended from the S2-100, created in 1929 by the Swiss company Waffenfabrik Solothurn AG. In total, about 1940 machine guns were produced before 17.
7,92 mm aircraft turret machine gun MG. fifteen
Automatic machine gun MG. 15 worked on the principle of recoil of the barrel with its short stroke. The barrel bore was locked by turning the locking clutch. No MG ammo. 15 weighed 8,1 kg, length - 1 mm. Rate of fire: 090–900 rounds/min. A 1-round double drum magazine was used to feed the machine gun with cartridges.
After MG. 15 in defensive installations began to be replaced with faster-firing 7,92 mm MG. 81 and 13,2 mm MG. 131, a significant number of MG.15 turret machine guns remained in warehouses. Taking into account the fact that obsolete rifle-caliber aircraft machine guns with minimal modifications could be used to create anti-aircraft installations, they quickly found use. In fact, all that was required to do this was to install the machine gun body on a sufficiently long vertical stand with a hinge and ensure stability. The necessary sighting devices were available on the weapon.
Sometimes the security of German field airfields did not bother creating specialized anti-aircraft tripods, the manufacture of which required time and materials. In this case, the turret rack, dismantled from the aircraft, together with the machine gun, was driven into the end of a log dug vertically into the ground.
Thus, comparing the Soviet DA with its foreign classmates, we can state that other foreign models, especially those that appeared later, in most cases surpassed the domestic aircraft machine gun in rate of fire, which was important in air combat. In terms of weight and dimensions, all machine guns under consideration were approximately equivalent. At the same time, the Degtyarev machine gun had a fairly simple and durable design, which had a positive effect on reliability.
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