After the end of World War II, the American armed forces received a significant number of medium and large-caliber anti-aircraft guns, small-caliber anti-aircraft guns and machine gun installations. If in the navy the role of anti-aircraft artillery remained for quite a long time, since the naval universal anti-aircraft artillery of medium caliber and small-caliber anti-aircraft guns were the last barrier on the way of enemy aircraft, then in the US Army and the Marine Corps they hastened to abandon most of the anti-aircraft guns. First of all, this concerned medium and large-caliber guns and towed 40-mm anti-aircraft guns. After the end of the war, about half of the anti-aircraft batteries were reduced, towed guns were sent to storage bases, and stationary positions were mothballed. Anti-aircraft units deployed in the United States were mainly reduced, and was due to the fact that in the USSR until the mid-50s there were no bombers capable of performing a combat mission on the continental part of America and returning back. In the 1950s, jet fighters appeared, whose flight speed at high altitudes became approximately double that of the fastest piston aircraft. The creation of anti-aircraft missiles, capable of shooting down high-altitude bombers with a high probability, further reduced the role of large-caliber anti-aircraft guns.
However, the American military was not going to completely abandon anti-aircraft artillery. It is worth saying that during the war years in the United States, very effective anti-aircraft systems and fire control devices were created. In 1942, taking into account the operating experience of previous models, the 90-mm M2 anti-aircraft gun was put into production. Unlike earlier guns of the same caliber, the new anti-aircraft gun could lower the barrel below 0 °, which made it possible to use it in coastal defense and to combat enemy armored vehicles. The device of the gun made it possible to use it for firing at mobile and stationary ground targets. The maximum firing range of 19,000 m made it an effective means of counter-battery warfare. Compared to the 90-mm M1A1 anti-aircraft gun, the design of the frame has become much simpler, which led to a weight reduction of 2000 kg and significantly reduced the time for bringing the M2 into a combat position. A number of fundamental innovations were introduced into the design of the gun, the M2 model received an automatic supply of shells with a fuse installer and a rammer. Due to this, the installation of the fuse became faster and more accurate, and the rate of fire increased to 28 rounds per minute. But the weapon became even more effective in 1944 with the adoption of a projectile with a radio fuse. 90-mm anti-aircraft guns were usually reduced to 6-gun batteries, from the second half of the war they were given radars for detection and fire control.
Anti-aircraft 90-mm gun M2
The anti-aircraft battery was adjusted using the SCR-268 radar. The station could see aircraft at a range of up to 36 km, with an accuracy of 180 m in range and an azimuth of 1, 1 °. This was especially important when repelling enemy raids at night. 90-mm anti-aircraft guns guided by radar shells with radio fuses regularly shot down German unmanned aircraft-shells "V-1" over southern England.
By the time the hostilities ended in 1945, the American industry had produced almost 8,000 90-mm anti-aircraft guns of various modifications. Some of them were installed in stationary positions in special armored towers, mainly in the areas of naval bases and the vicinity of large administrative and industrial centers on the coast. It was even proposed to equip them with automatic devices for loading and supplying ammunition, as a result of which there was no need for a gun crew, since guidance and firing could be controlled remotely. According to American documents, under the Lend-Lease agreement, 25 batteries of 90-mm anti-aircraft guns, equipped with SCR-268 radars, were sent to the USSR.
American 90mm M2 anti-aircraft guns fire at ground targets in Korea
At the end of the 40s, American 90-mm anti-aircraft batteries, deployed in Europe and Asia, received new fire control radars, which made it possible to more accurately adjust fire at high-speed targets flying at medium and low altitudes. After the landing of the UN Forces in Korea, M2 anti-aircraft guns with new guidance radars took part in the hostilities. However, they almost never fired on North Korean aircraft, but these guns were very often used to provide fire support to ground units and counter-battery warfare. In the 50-60s, 90-mm anti-aircraft guns were transferred in large numbers to the armed forces of states friendly to the United States. So, in a number of European NATO member countries, they were operated until the end of the 70s.
In 1943, the 120-mm M1 anti-aircraft gun was adopted in the United States. For its high ballistic performance in the army, it was nicknamed the "stratospheric gun". This anti-aircraft gun could hit aerial targets with a projectile weighing 21 kg at an altitude of 18,000 m, producing up to 12 rounds per minute.
Radar SCR-584
Targeting and anti-aircraft fire control was carried out using the SCR-584 radar. This radar, very advanced for the mid-40s, operating in the 10-cm radio frequency range, could detect targets at a distance of 40 km and conduct anti-aircraft fire adjustments at a distance of 15 km. The use of radar in combination with an analog computing device and projectiles with radio fuses made it possible to conduct fairly accurate anti-aircraft fire at aircraft flying at night at medium and high altitudes. An important circumstance that increased the striking effect was that the 120-mm fragmentation projectile weighed almost 2.5 times more than the 90-mm one. However, as you know, the disadvantages - the continuation of the merits, with all their advantages, 120-mm anti-aircraft guns were very limited in mobility. The weight of the gun was impressive - 22,000 kg. Transportation of the 120-mm anti-aircraft gun was carried out on a two-axle wagon with twin wheels, and was served by a crew of 13 people. The travel speed even on the best roads did not exceed 25 km / h.
120-mm anti-aircraft gun M1
When firing, the 120-mm anti-aircraft gun was hung out on three powerful supports, which were lowered and raised hydraulically. After lowering the legs, the tire pressure was released for greater stability. As a rule, four-gun batteries were based not far from vital objects in pre-prepared stationary concreted positions. During the war, 120mm anti-aircraft guns were deployed along the American West Coast to defend against anticipated Japanese air attacks that never materialized. Sixteen M1 cannons were sent to the Panama Canal zone and several batteries were stationed in and around London to help defend against the V-1. One four-gun battery with SCR-584 radar was sent to the Soviet Union.
In total, the American industry handed over 550 120-mm anti-aircraft guns to the military. Most of them have never left the continental United States. These long-range and high-altitude anti-aircraft guns were in service until the early 60s, when the MIM-14 Nike-Hercules anti-aircraft missile systems began to enter the armament of the army air defense units.
Due to their heavy weight, 90 and 120-mm anti-aircraft guns were most often used in object air defense, while the troops were usually covered with 12, 7-mm anti-aircraft machine gun mounts and small-caliber anti-aircraft machine guns. If the US Navy relied on 20-mm Oerlikon anti-aircraft machine guns, then the main means of protection against aviation of troops on the march in wartime were large-caliber 12, 7 mm M2 machine guns. This machine gun was created by John Browning in 1932. Browning's large-caliber machine guns used a powerful.50 BMG cartridge (12, 7 × 99 mm), which provided a 40 g bullet with an initial velocity of 823 m / s. At a range of 450 m, the armor-piercing bullet of this cartridge is capable of penetrating a 20 mm steel plate. As an anti-aircraft model, a model with a bulky water-cooled casing was originally produced, an air-cooled barrel weapon was intended to combat light armored vehicles and as a means of supporting infantry.
To provide the required intensity of fire in the air-cooled version, a heavier barrel was developed, and the machine gun received the designation Browning M2HB. The rate of fire was 450-600 rds / min. The machine gun of this modification became widespread and was used as an anti-aircraft gun in single, twin and quad anti-aircraft mounts. The most successful was the quad M45 Maxson Mount. Its weight in combat position was 1087 kg. The firing range at air targets is about 1000 m. The rate of fire is 2300 rounds per minute.
ZPU M51
ZPU Maxson Mount, starting in 1943, were produced in both towed and self-propelled versions. The towed version on a four-axle trailer received the designation M51. When transferred to a firing position, special supports were lowered to the ground from each corner of the trailer to give stability to the installation. Guidance was carried out using electric drives powered by lead-acid batteries. The trailer also housed a gasoline-electric generator to charge the batteries. The electric motors of the guidance drives were powerful, capable of withstanding the heaviest loads, thanks to which the installation had a guidance speed of up to 50 ° per second.
ZSU M16
The most common in the American army ZSU with quad machine-gun mounts was the M16, based on the M3 half-track armored personnel carrier. A total of 2877 of these machines were produced. The Maxson Mounts were usually used to protect transport convoys on the march or military units in places of concentration from attacks by assault aircraft. In addition to its direct purpose, the quad mounts of large-caliber machine guns were a very powerful means of fighting manpower and lightly armored vehicles, earning the unofficial nickname among the American infantrymen - the "meat grinder". They were especially effective in street battles; large elevation angles made it possible to turn attics and upper floors of buildings into sieves.
The M16 anti-aircraft self-propelled gun was very similar to the M17 ZSU, which differed in the type of conveyor. The M17 was built on the basis of the M5 armored personnel carrier, which differed from the M3 only in some units and assemblies, as well as in the hull manufacturing technology. Quadruple installations of large-caliber machine guns in the American army were used until the end of the 60s, until supplies began to the troops of the ZSU "Vulcan".
Anti-aircraft guns with large-caliber M2 machine guns proved to be a very effective means of repelling low-altitude attacks from enemy aircraft. Due to the high combat and service-operational characteristics for their time, anti-aircraft 12, 7 mm machine guns became widespread in the armed forces of the United States and its allies, and is still used today.
Shortly before the war, the army's anti-aircraft units began to receive a 37-mm anti-aircraft machine gun, developed by John Browning. But the military was not satisfied with the insufficiently powerful ammunition, which did not provide the required initial velocity of the projectile, which made it difficult to defeat aircraft flying at high speed. Just at this time, the British turned to the Americans with a request to use part of their production capacity for the production of 40-mm Bofors L60 anti-aircraft guns for the UK. Having tested the Bofors, the American military was convinced of the superiority of these anti-aircraft guns over the domestic system. A set of technological documentation handed over by the British helped to speed up the establishment of production. In fact, the license for the production of 40-mm anti-aircraft guns in the United States was officially issued by the Bofors company after the beginning of their massive entry into the troops. The American version of the Bofors L60 was designated 40 mm Automatic Gun.
40-mm anti-aircraft machine gun Bofors L60
A fragmentation projectile weighing 0.9 kg left the barrel at a speed of 850 m / s. The rate of fire is about 120 rds / min. The assault rifles were loaded with 4-shot clips, which were inserted manually. The gun had a practical ceiling of about 3800 m, with a range of 7000 m. As a rule, one hit of a 40-mm fragmentation projectile on an enemy attack aircraft or dive bomber was enough to defeat it.
The gun is mounted on a four-wheeled towed "cart". In case of urgent need, the shooting could be carried out directly from the gun carriage, "from the wheels" without additional procedures, but with less accuracy. In the normal mode, the carriage frame was lowered to the ground for greater stability. The transition from the "traveling" position to the "combat" position took about 1 minute. With a mass of an anti-aircraft gun of about 2000 kg, towing was carried out by a truck. The calculation and ammunition were located in the back. At the end of the 40s, most of the 40-mm anti-aircraft guns, as they no longer meet modern requirements, were withdrawn from the army air defense units, they were stored in warehouses until the Red Eye MANPADS was adopted.
The big drawback of the towed 40-mm anti-aircraft machine gun was that it could not fire straight away. In this regard, in addition to towed options, several types of 40-mm SPAAG were developed. In the USA "Bofors" were mounted on modified 2.5-ton chassis of GMC CCKW-353 trucks. These self-propelled guns were used to support the ground forces and provided protection against air attacks without the need for a stationary installation on the ground and deploying the system into a combat position. The armor-piercing shells of the 40-mm gun could penetrate 50-mm homogeneous steel armor at a distance of 500 meters.
The experience of combat operations revealed the need to have a SPAAG on a tracked chassis to accompany tank units. Tests of such a machine took place in the spring of 1944 at the Aberdeen Tank Range. The ZSU, which received the serial designation M19, used the chassis of the M24 Chaffee light tank and was armed with two 40-mm anti-aircraft guns mounted in an open-top turret. The shooting was carried out using an electric trigger. Rotation of the turret and the swinging part of the cannons is controlled by a manual electro-hydraulic drive. The ammunition load was 352 shells.
For the mid-40s, the self-propelled anti-aircraft gun had good data. The vehicle, which weighed about 18 tons, was covered with 13 mm armor, which provided protection from bullets and shrapnel. On the M19 highway, it accelerated to 56 km / h, the speed over rough terrain was 15-20 km / h. That is, the mobility of the ZSU was on the same level as the tanks.
ZSU М19
But the ZSU did not have time to go to war, since it took about a year to eliminate "children's sores" and establish mass production. They built a few, only 285 vehicles, before the end of hostilities, several dozen M19s were delivered to the troops. Paired anti-aircraft 40-mm self-propelled guns were actively used during the Korean War for firing at ground targets. Since ammunition was consumed very quickly when firing in bursts, about 300 more shells in cassettes were transported in special trailers. By the end of the 50s, all M19s were removed from service. The least worn-out vehicles were handed over to the Allies, and the rest were written off for scrap. The main reason for the short service life of the M19 installations was the refusal of the American army from the M24 light tanks, which were unable to fight the Soviet T-34-85. Instead of the M19, the ZSU M42 was adopted. This self-propelled gun with anti-aircraft weapons similar to the M19 was created on the basis of the M41 light tank in 1951. The ZSU M42 turret was identical to that used on the M19, only on the M19 it was installed in the center of the hull, and on the M42 at the back. Compared to the previous model, the thickness of the frontal armor increased by 12 mm, and now the forehead of the hull could hold the armor-piercing bullets of a large-caliber machine gun and small-caliber projectiles. With a combat weight of 22.6 tons, the car could accelerate on the highway to 72 km / h.
ZSU М42
The self-propelled anti-aircraft gun, also known as "Duster" (English Duster), was built in a fairly large series and was popular among the troops. From 1951 to 1959, about 3,700 units were produced at the General Motors Corporation's Cadillac Motor Sag facility in Cleveland.
Guidance is carried out using an electric drive, the tower is capable of rotating 360 ° at a speed of 40 ° per second, the vertical guidance angle of the gun is from -3 to + 85 ° at a speed of 25 ° per second. In the event of a failure of the electric drive, aiming can occur manually. The fire control system included an M24 mirror sight and an M38 calculator, the data into which was entered manually. Compared to the M19, the ammunition load was increased and amounted to 480 shells. The combat rate of fire when firing bursts reached 120 rounds per minute with an effective fire range against air targets of up to 5000 m. For self-defense, there was a 7.62 mm machine gun.
A significant drawback of the "Duster" was the lack of a radar sight and a centralized anti-aircraft battery fire control system. All this significantly reduced the effectiveness of anti-aircraft fire. The baptism of fire of the American M42 took place in Southeast Asia. Suddenly, it turned out that 40-mm twin anti-aircraft guns, protected by armor, are very effective in repelling guerrilla attacks on transport convoys. In addition to escorting convoys, "Dasters" were actively used throughout the Vietnam War to provide fire support to ground units. By the mid-70s, M42s were mainly withdrawn from the combat units of the "first line" and replaced by the ZSU M163 with a 20-mm Vulcan anti-aircraft gun. But due to the fact that the effective firing range of 40-mm guns was significantly greater, in some American army units and in the National Guard, 40-mm ZSU served until the mid-80s.
