German 20-mm rapid-fire anti-aircraft guns were considered a fairly effective means of dealing with an air enemy at low altitudes. However, with all the advantages of the Flak 28, FlaK 30 and Flak 38 anti-aircraft guns, their rate of fire was not always sufficient to confidently defeat fast-moving targets, and the Flakvierling 38 quad mounts were too heavy and cumbersome. The destructive effect of 20-mm fragmentation shells was still very modest, and several hits were often required to reliably disable an armored attack aircraft. In addition, in addition to increasing the fragmentation and high-explosive action of shells, it was highly desirable to increase the effective firing range and height reach.
However, the Germans had some experience of using captured 25 mm French anti-aircraft guns 25 mm CA mle 39 and 25 mm CA mle 40, issued by Hotchkiss. For their time, these were quite modern installations: the 25 mm CA mle 39 had a detachable wheel travel, and the 25 mm CA mle 40 was mounted on the decks of warships and in stationary positions.
The anti-aircraft gun 25 mm CA mle 39 was the largest and heavier than the 20 mm German FlaK 30/38. In combat position, the French anti-aircraft machine gun weighed 1150 kg. The rate of fire is about the same as that of the FlaK 30 - 240 rounds / min. Food was supplied from a detachable store for 15 shells. Effective firing range - up to 3000 m. Height reach - 2000 m. Vertical guidance angles: -10 ° - 85 °. Effective firing range - up to 3000 m. Ceiling - 2000 m.
In terms of the damaging effect, the 25-mm French shells were significantly superior to the 20-mm German shells. A high-explosive incendiary 25-mm projectile weighing 240 g left the barrel with an initial speed of 900 m / s and contained 10 g of explosives. Upon hitting the duralumin sheet, it formed a hole, the area of which was approximately twice as large as in the explosion of a 20-mm projectile containing 3 g of explosive. At a distance of 300 meters, an armor-piercing projectile weighing 260 g, with an initial speed of 870 m / s along the normal, pierced 28-mm armor.
After the occupation of France, the Germans got about four hundred 25-mm anti-aircraft guns. In the Wehrmacht, the 25 mm CA mle 39 mount received the designation 2.5 cm Flak 39 (f). Most of the 25-mm anti-aircraft guns of French origin were placed in the fortifications of the Atlantic Wall, but some of the 25-mm anti-aircraft guns of French production still ended up on the Eastern Front.
The German anti-aircraft gunners were quite satisfied with the firing range of captured French anti-aircraft guns, and the striking effect of 25-mm shells. However, calculations have shown that it is possible to achieve a greater destructive effect and firing range by increasing the caliber of anti-aircraft guns to 30-mm, and to ensure the required rate of fire, it is necessary to use tape power.
German 30-mm anti-aircraft guns
The first German 30-mm anti-aircraft guns were artisanal MK.103 aircraft guns mounted on improvised turrets.
Automatic cannon MK.103 without ammunition weighed 145 kg. The weight of the box with tape for 100 shots is 94 kg. The scheme of functioning of the automation is mixed: the extraction of the sleeve, the supply of the next cartridge and the advancement of the tape occurred due to a short rollback of the barrel, and the removal of powder gases was used to cocking the shutter and unlocking the barrel bore. The food was supplied from a metal loose belt 70–125 rounds long. Rate of fire - up to 420 rds / min.
Since this gun had a fairly strong recoil, it was used to a limited extent as part of the armament of single-engine fighters. Serial production of MK.103 was carried out from July 1942 to February 1945. By the middle of 1944, a significant number of unclaimed 30-mm guns had accumulated in warehouses, which became the reason for their use in anti-aircraft installations.
In the summer of 1943, the first 30mm cannons were mounted on primitive and rather crude turrets. Thus, ground technical personnel tried to strengthen the air defense of German field airfields.
Despite the unsightly appearance, such handicraft installations showed good results when firing at air targets. The 30-mm high-explosive and high-explosive tracer shells had the greatest destructive effect: 3 cm M. Gesch. o. Zerl and 3 cm M. Gesch. Lspur. o. Zerl. The first projectile weighing 330 g contained 80 g of TNT, the second, with a weight of 320 g, was loaded with 71 g of phlegmatized RDX mixed with aluminum powder. For comparison: the Soviet 37-mm fragmentation-tracer projectile UOR-167 weighing 0.732 g, which was included in the ammunition of the 61-K anti-aircraft machine gun, contained 37 g of TNT.
For the manufacture of especially powerful 30-mm projectiles with a high explosive filling ratio, the technology of "deep drawing" was used, followed by quenching of the steel body with high-frequency currents. The hit of even single 30-mm high-explosive and high-explosive tracer shells in the Il-2 attack aircraft was guaranteed to lead to the shooting down of the aircraft.
Taking into account the successful experience of using improvised 30-mm anti-aircraft guns, the designers of Waffenfabrik Mauser AG crossed the MK.103 aircraft cannon with the 20-mm Flak 38 anti-aircraft gun. wartime improvisation, on the whole it turned out to be quite successful.
Increasing the caliber from 20 to 30 mm made the installation about 30% more difficult. The weight of 3.0 cm Flak 103/38 in the transport position was 879 kg, after separation of the wheel travel - 619 kg. The effectiveness of the 30-mm anti-aircraft gun has increased by about 1.5 times. At the same time, the effective range of fire increased by 20-25%. The heavier 30-mm projectile was slower to lose its energy, the maximum oblique firing range at air targets was 5700 m, and the altitude reach was 4500 m.
The combat rate of fire was significantly increased due to the use of a feed belt and a box for 40 shells. In addition, the power of the 30-mm projectile was twice as large as the 20-mm projectile. It was experimentally found that in most cases, to defeat an armored attack aircraft or a twin-engine dive bomber, no more than two hits from a fragmentation tracer or one hit from a high-explosive projectile were required.
By analogy with the 20-mm quadruple anti-aircraft gun 2.0 cm Flakvierling 38, at the end of 1944, the 3.0 cm Flakvierling 103/38 was created using MK.103 cannons. Compared to the 2.0 cm Flakvierling 38, the weight of the 3.0 cm Flakvierling 103/38 in the firing position has increased by about 300 kg. But the increase in weight was more than offset by the increased combat characteristics. In 6 seconds, the quad unit could fire 160 rounds in a continuous burst, with a total mass of 72 kg.
Externally, the 30-mm quad mount differed from the 2.0 cm Flakvierling 38 in longer and thicker barrels, equipped with a multi-chamber muzzle brake and cylindrical boxes for projectile belts.
As in the case of 20-mm anti-aircraft guns, single-barreled and quadruple anti-aircraft guns based on MK.103 were used in a towed version, placed on the chassis of armored personnel carriers, tanks, and were also mounted in truck bodies and on railway platforms.
Although attempts were made to establish the mass production of single-barreled and quadruple anti-aircraft guns, and in the second half of 1944 an order was issued for 2000 Flakvierling 103/38 and 500 Flakvierling 103/38, the industry of the Third Reich was unable to meet the planned production volumes. In total, a little more than 500 single-barreled and quadruple units were transferred to the customer, and due to the relative small number of them, they did not have a noticeable effect on the course of hostilities.
The strengthening of the anti-submarine aircraft of the allies and the increased losses of German submarines required the replacement of the 37-mm semi-automatic anti-aircraft guns SK C / 30U, in which loading was carried out one round at a time, and therefore, the combat rate of fire did not exceed 30 rds / min.
In 1943, the kringsmarine command initiated the development of a paired 30-mm anti-aircraft machine gun. In addition to increasing the rate of fire, while maintaining the firing range of the 37-mm cannon, the new 30-mm anti-aircraft gun was supposed to be relatively light, compact and reliable.
In the summer of 1944, the Waffenwerke Brünn company (as the Czech Zbrojovka Brno was called in wartime) presented a twin anti-aircraft gun for testing, which received the designation 3, 0 cm MK. 303 (Br) (also referred to as 3.0 cm Flakzwilling MK. 303 (Br)).
Unlike 3, 0 cm Flak 103/38 with a belt feed, the new anti-aircraft gun had a system for feeding ammunition from magazines for 10 or 15 shells, with a rate of fire from two barrels up to 900 rds / min. Thanks to the longer barrel, the muzzle velocity of the armor-piercing projectile was increased to 900 m / s, which increased the effective firing range at air targets.
Serial production 3.0 cm MK. 303 (Br) began at the end of 1944. Before the surrender of Germany, more than 220 paired 30-mm anti-aircraft guns were built. Although the anti-aircraft gun is 3.0 cm MK. 303 (Br) was originally intended for installation on warships, most of the 30-mm twin was used in land-based stationary positions.
The use of captured 30-mm anti-aircraft guns
Due to the fact that the German industry was unable to produce a significant number of 30-mm anti-aircraft guns, their contribution to the confrontation with Soviet, American and British aircraft during the war years was small. Unlike 20-mm anti-aircraft guns, albeit more effective, but small in number, 30-mm anti-aircraft guns did not become widespread in the post-war years. At the same time, in a number of countries, they had a noticeable impact on the process of creating new rapid-fire anti-aircraft guns.
German 30-mm rapid-fire cannons were carefully studied by Soviet specialists. After trials of the captured MK.103, she received a positive assessment. In the conclusion, based on the results of the tests, it was noted that the 30-mm German automatic gun with a belt feed has a high rate of fire for its caliber. The design of the weapon is quite simple and reliable. The main disadvantage, according to our experts, was the strong shock loads during the operation of the automation. In terms of the complex of combat characteristics, the MK.103 occupied an intermediate position between the 23-mm VYa cannon and the 37-mm NS-37.
Czechoslovakia became the only country where, in the post-war period, 30-mm anti-aircraft guns, previously used in the armed forces of Nazi Germany, were in service in noticeable quantities.
As you know, the Czechs quite widely used the developments created by order of the Nazis, and in the post-war period improved the models of equipment and weapons made in the Third Reich.
In the mid-1950s, supplies of the M53 double-barreled anti-aircraft gun, also known as the “30-mm anti-aircraft gun ZK.453 mod. 1953 . This anti-aircraft gun structurally had a lot in common with the 3.0 cm MK. 303 (Br).
The artillery part of the installation was mounted on a four-wheeled cart. At the firing position, she was hung out on jacks. The mass in the stowed position was 2100 kg, in the combat position - 1750 kg. Calculation - 5 people.
The automatic gas engine provided a total rate of fire from two barrels of 1000 rds / min. The anti-aircraft gun was fed from hard cassettes for 10 shells, the real combat rate of fire was 100 rds / min.
The 30-mm Czechoslovak anti-aircraft gun had high ballistic characteristics. A high-explosive incendiary projectile weighing 450 g left a barrel 2363 mm long with an initial speed of 1000 m / s. Oblique firing range at air targets - up to 3000 m.
The ammunition load included armor-piercing incendiary tracer and high-explosive fragmentation incendiary shells. An armor-piercing incendiary tracer projectile weighing 540 g with an initial speed of 1000 m / s at a distance of 300 m could penetrate 50 mm steel armor along the normal.
Comparing the Czechoslovak ZK.453 with the Soviet 23-mm ZU-23, it can be noted that the 30-mm installation was heavier and had a lower combat rate of fire, but at the same time the effective fire zone was about 25% higher, and its projectile had a great destructive effect … Paired towed and self-propelled units ZK.453 were used in the military air defense of Czechoslovakia, Yugoslavia, Romania, Cuba, Guinea and Vietnam.
German 37 mm anti-aircraft guns
During World War II, most of the belligerent countries had 37–40 mm anti-aircraft guns. Compared to anti-aircraft guns of 20-mm and 30-mm caliber (especially with quadruple ones), 37-mm guns had a lower combat rate of fire. But much heavier and more powerful 37-mm projectiles made it possible to fight air targets flying at a distance and height inaccessible to anti-aircraft guns of a smaller caliber. With close values of the initial velocity, the 37-mm projectile weighed 2, 5-5, 8 times more than the 20-30-mm, which ultimately determined a significant superiority in muzzle energy.
The first German 37-mm automatic cannon was the 3.7 cm Flak 18 (3.7 cm Flugzeugabwehrkanone 18). This gun was created by the specialists of the Rheinmetall Borsig AG concern in 1929 based on the developments of the Solothurn Waffenfabrik AG company. The official acceptance into service took place in 1935.
The 37-mm assault rifle was originally created as a dual-use artillery system: to combat aircraft and armored vehicles. Due to the high initial velocity of the armor-piercing projectile, this gun could surely hit tanks with bulletproof armor.
The cannon automatics worked due to the recoil energy with a short barrel stroke. The shooting was carried out from a pedestal gun carriage, supported by a cruciform base on the ground. In the stowed position, the gun was transported on a four-wheeled cart. The mass of the gun in the combat position is 1760 kg, in the stowed position - 3560 kg. Calculation - 7 people. Angles of vertical guidance: from -7 ° to +80 °. In the horizontal plane, there was the possibility of a circular attack. Guidance drives are two-speed. The maximum firing range at air targets is 4200 m.
For firing the 3, 7 cm Flak 18, a unitary shot known as the 37x263B was used. Cartridge weight - 1, 51-1, 57 kg. An armor-piercing tracer projectile weighing 680 g in a barrel length of 2106 mm accelerated to 800 m / s. The thickness of the armor pierced by the armor-piercing tracer at a distance of 800 m at an angle of 60 ° was 25 mm. The ammunition load also included shots: with fragmentation-tracer, fragmentation-incendiary and fragmentation-incendiary-tracer grenades, an armor-piercing high-explosive projectile, as well as a subcaliber armor-piercing tracer projectile with a carbide core. Power was supplied from 6-charge clips on the left side of the receiver. Rate of fire - up to 150 rds / min.
In general, the 37-mm anti-aircraft gun was quite efficient and quite effective against aircraft at a distance of up to 2000 m, and could successfully operate against lightly armored ground targets and manpower in line-of-sight aisles. Despite the fact that by the beginning of World War II, this 37-mm anti-aircraft gun was replaced in production with more advanced models, its operation continued until the end of hostilities.
The first combat use of the 3, 7 cm Flak 18 took place in Spain, where the gun performed well on the whole. However, the anti-aircraft gunners complained about the difficulty of redeploying and transporting. The excessive mass of the anti-aircraft gun in the transport position was a consequence of the use of a heavy and inconvenient four-wheeled "cart", which was towed at a speed of no more than 30 km / h.
In this regard, in 1936, using an artillery unit 3, 7 cm Flak 18 and a new gun carriage, an anti-aircraft machine gun 3, 7 cm Flak 36 was created. 2400 kg. While maintaining the ballistic characteristics and rate of fire of the previous modification, the elevation angles were increased in the range from -8 to + 85 °.
The carriage with four supports with the help of a chain winch was removed and put on a single-axle carriage in three minutes. Highway towing speed increased to 60 km / h.
The creators of the 3, 7 cm Flak 36 managed to achieve a high design perfection of the anti-aircraft gun, and the next stage in the increase in the effectiveness of 37-mm anti-aircraft guns was an increase in the accuracy of shooting.
The next modification, designated 3, 7 cm Flak 37, used the Sonderhänger 52 anti-aircraft sight with a calculating device. The fire control of the anti-aircraft battery was carried out using the Flakvisier 40 rangefinder. Thanks to these innovations, the accuracy of fire at distances close to the limit increased by about 30%.
The installation of 3, 7 cm Flak 37 visually differed from earlier models by a modified barrel casing, which is associated with a simplified production technology.
In general, 3, 7 cm Flak 36 and 3, 7 cm Flak 37 met the requirements for 37-mm anti-aircraft guns. However, when firing at rapidly moving air targets at a distance of up to 1000 m, it was highly desirable to increase the rate of fire. In 1943, the Rheinmetall Borsig AG concern proposed a 37-mm towed anti-aircraft gun 3, 7 cm Flak 43, the vertical guidance angle of the barrel of which was brought to 90 °, and the principle of operation of the automatic artillery unit underwent significant revision. The short stroke of the barrel during recoil was combined with a gas vent mechanism that unlocks the bolt. The increased shock loads were compensated by the introduction of a spring-hydraulic damper. To increase the practical rate of fire and the length of the continuous burst, the number of rounds in the clip was increased to 8 units.
Due to all this, it was possible to significantly reduce the time required to perform actions when firing a shot, and the rate of fire increased to 250-270 rds / min, which slightly exceeded the rate of fire of a 20-mm machine gun 2, 0 cm FlaK 30. The combat rate of fire was 130 rds / min. min. The mass in the firing position is 1250 kg, in the stowed position - 2000 kg. The barrel length, ammunition and ballistics of the Flak 43 remain unchanged compared to the Flak 36.
The antiaircraft gun became easier to operate: the loading process became easier, and the gun could be fully controlled by one gunner. To protect the crew, an armored shield with two flaps was installed on most of the towed installations 3, 7 cm Flak 43. The gun was transported on a single-axle sprung trailer with pneumatic and hand brakes, as well as a winch for lowering and raising the gun when it was transferred from the traveling position to the combat position and vice versa. In exceptional cases, shooting from a cart was allowed, while the horizontal firing sector did not exceed 30 °. The Flak 43 artillery unit was mounted on a triangular base with three frames, on which it rotated. The beds had jacks for leveling the anti-aircraft gun. To increase the effectiveness of anti-aircraft fire, centralized aiming from a single anti-aircraft fire control device was adopted as the main one. At the same time, individual sights were retained for use outside the 3, 7 cm Flak 43 anti-aircraft battery.
Simultaneously with an increase in the rate of fire, due to an increase in the share of stamped parts, the technology for the production of anti-aircraft guns was improved and the metal consumption was reduced. This, in turn, made it possible to quickly establish the serial production of the new 37-mm anti-aircraft gun. In July 1944, 180 assault rifles were delivered, in December - 450 guns. In March 1945, 1,032 guns 3, 7 cm Flak 43 were in service.
In parallel with 3, 7 cm Flak 43, a twin installation Flakzwilling 43 was created. Artillery machines in it were located one above the other, and the cradles on which the machines were installed were connected to each other by a thrust forming a parallelogram articulation. Each gun was located in its cradle and formed a swinging part rotating relative to its annular pins.
With the vertical arrangement of the barrels, there was no dynamic torque in the horizontal plane, knocking down the aiming. The presence of individual pins for each machine gun minimized the disturbances affecting the swinging part of the anti-aircraft installation, and made it possible to use the artillery unit from single installations without any alterations. In the event of failure of one gun, it was possible to fire from the second without disrupting the normal aiming process.
The disadvantages of such a scheme are a continuation of the advantages: with a vertical arrangement, the height of the entire anti-aircraft installation and the height of the line of fire increased. In addition, such an arrangement is only possible for side-fed vending machines.
In general, the creation of Flakzwilling 43 was quite justified. The mass of the twin 37 mm mount compared to the Flak 43 has increased by about 40%, and the combat rate of fire has almost doubled.
Until March 1945, the German industry produced 5918 37-mm Flak 43 anti-aircraft guns, and 1187 twin Flakzwilling 43. Despite the higher level of combat characteristics, Flak 43 was not able to completely displace the Flak 36/37 from the production lines of 37-mm anti-aircraft guns 3. 7 cm Flak 36/37, of which more than 20,000 units were manufactured.
In the Wehrmacht, towed 37-mm anti-aircraft guns were reduced to batteries of 9 guns. The anti-aircraft battery of the Luftwaffe, placed in stationary positions, could have up to 12 37-mm cannons.
In addition to being used in a towed version, the 3, 7-cm Flak 18 and Flak 36 anti-aircraft guns were installed on railway platforms, various trucks, half-track tractors, armored personnel carriers and tank chassis.
Unlike towed 37-mm anti-aircraft guns deployed at prepared firing positions as part of the battery, the calculation of self-propelled anti-aircraft guns when firing at air targets, due to cramped conditions, as a rule, did not use an optical rangefinder, which negatively affected the accuracy of firing. In this case, amendments to the sight were made in the course of firing, based on the trajectory of the tracer shells relative to the target.
Anti-aircraft 37-mm self-propelled guns were actively used on the Eastern Front, operating mainly in the front-line zone. They accompanied transport convoys and were part of the anti-aircraft division, which provided air defense for some tank and motorized divisions.
If necessary, the ZSU was used as a mobile anti-tank reserve. In the case of targeted use against armored vehicles, the ammunition load of 37-mm anti-aircraft guns could include a sub-caliber projectile weighing 405 g, with a tungsten carbide core and an initial speed of 1140 m / s. At a distance of 600 m along the normal, it pierced 90 mm armor. But, due to the chronic shortage of tungsten, 37-mm sub-caliber shells were not often used.
At the final stage of the war, in the face of an acute shortage of anti-tank weapons, the German command decided to put most of the 37-mm anti-aircraft guns on direct fire for firing at ground targets.
Due to low mobility, automatic anti-aircraft guns were used mainly in pre-equipped positions in defense nodes. Due to their good penetration and high rate of fire for their caliber, they posed a certain danger to Soviet medium T-34 tanks and, when using fragmentation shells, could successfully fight infantry that did not take shelter.
Use of 37-mm German anti-aircraft guns in the USSR
In parallel with the "20-mm automatic anti-aircraft and anti-tank gun arr. 1930" mentioned in the previous publication (2-K), the German company Butast in 1930 supplied technical documentation and a number of semi-finished products to the 37-mm anti-aircraft gun, which later received the designation 3, 7 cm Flak 18 in Germany. In the USSR, this system was named "37-mm automatic anti-aircraft gun mod. 1930 ". Sometimes it was called the 37-mm gun "N" (German).
They tried to launch the antiaircraft gun into mass production at plant number 8, where it was assigned the factory index 4-K. In 1931, three guns, assembled from German parts, were presented for testing. However, plant No. 8 failed to achieve the proper quality of manufacturing of components during mass production, and an attempt to mass production in the USSR of a 37-mm anti-aircraft gun of the German model failed.
During World War II, the Red Army captured several hundred towed 37-mm anti-aircraft guns and the ZSU armed with them. However, official documents on the use of these weapons in the Red Army could not be found.
In the memoir literature, there is a mention that captured 37-mm German anti-aircraft guns were installed in defense nodes and were used exclusively for firing at ground targets.
It can be assumed that due to ignorance of the captured material, the Red Army soldiers could not competently operate 37-mm automatic cannons, and we did not know how to use German fire control devices. By the time the Red Army switched to strategic offensive operations, and Soviet troops began to capture a significant number of 37-mm German anti-aircraft guns, the air defense units of the Red Army were sufficiently saturated with domestic 37-mm automatic anti-aircraft guns of the 1939 model and received from the allies 40- mm "Bofors".
Captured German warships, which became part of the USSR Navy, had single-barreled and paired 37-mm universal rapid-fire guns 3, 7 cm SK C / 30 with a semi-automatic vertical sliding wedge gate with manual loading of each shot and automatic anti-aircraft guns 3, 7 cm Flak М42.
Although the 37-mm naval gun 3, 7 cm SK C / 30 in accuracy and firing range significantly exceeded the 37-mm ground anti-aircraft guns, by the standards of the 1940s, its rate of fire was unsatisfactory.
In this regard, the company Rheinmetall Borsig AG in 1943 redesigned the 3, 7 cm Flak 36 for naval requirements. Unlike the land-based prototype, the naval anti-aircraft gun was loaded with clips of five rounds from above, had an elongated barrel, a pedestal gun carriage and an anti-splinter shield. The rate of fire was 250 rds / min.
In the Soviet fleet, the semi-automatic 3, 7 cm SK C / 30s were replaced by the 37-mm automatic 70-K anti-aircraft gun mounts. Trophy machines 3, 7 cm Flak M42 served until the mid-1950s.
The use of 37-mm German anti-aircraft guns in the armed forces of other states
German 37-mm anti-aircraft guns 3, 7 cm Flak 36 were produced in Romania, and also supplied to Bulgaria, Hungary, Spain and Finland. After the end of World War II until the early 1950s, they were in service in Bulgaria, Spain and Czechoslovakia.
A significant number of 37-mm anti-aircraft guns were captured by the Allies during the liberation of the territories of France, Norway, Belgium and the Netherlands from the Nazis. The 3, 7 cm Flak 36 have been used for the longest time in Romania. They served in this country under the designation "Tun antiaerian Rheinmetall calibru 37 mm model 1939" for about two decades. In the early 1960s, they were transferred to warehouses. Three dozen 37-mm German-style anti-aircraft guns were in storage until the 80s.
Although the German 37-mm anti-aircraft guns had rather high combat and service-operational characteristics, in the first post-war decade they were almost completely replaced by anti-aircraft guns used in the winning countries: in the 40-mm Bofors L60 and 37-mm 61-K.
