At the beginning of World War II in the United States, there were no modern medium-caliber anti-aircraft guns in service with ground air defense units. Available in the amount of 807 units 76, 2-mm anti-aircraft guns M3 did not meet modern requirements. Their characteristics were not high, the weapon was complex and metal-consuming to manufacture.
76-mm anti-aircraft gun M3
This anti-aircraft gun was created in 1930 on the basis of the M1918 3-inch anti-aircraft gun, which, in turn, led the lineage from the coastal defense gun. The M3 anti-aircraft gun differed from the M1918 by a semi-automatic bolt, increased length and a changed barrel cutting pitch. The frame for the gun was a basement with a row of long beams, on which a fine-mesh crate was laid for the gun crew. The metal platform turned out to be very convenient for the crew, but its assembly and disassembly when changing positions was difficult and time consuming, took a lot of time and severely limited the mobility of the artillery system as a whole.
The gun turned out to be quite heavy for its caliber - 7620 kg. For comparison: the Soviet 76-mm anti-aircraft gun of the 1931 model (3-K) was twice as light - 3750 kg, surpassing the American gun in efficiency and being much cheaper.
The muzzle velocity of 5.8-kg projectile fired from the M3 barrel was 853 m / s. Anti-aircraft fire range - about 9000 m.
By the time the United States entered the war in 1941, the old M3s were involved in the defense of the Philippines against the Japanese. Some of these 3-inch skates still lingered in other parts of the Pacific Ocean, remaining in service until 1943.
76, 2-mm anti-aircraft gun M3 in one of the parks in Chicago
After the 76, 2-mm M3 anti-aircraft guns were replaced in the troops with more modern models, some of them participated in a propaganda campaign to increase the morale of the population. The guns were pushed through major cities in the continental United States and were demonstratively deployed in parks and squares.
With the outbreak of hostilities, when it became clear that the 3-inch anti-aircraft gun was ineffective, it was replaced in 1942 by the 90-mm M1 anti-aircraft gun. The caliber of the new anti-aircraft gun was chosen based on the mass of the projectile, a projectile of this caliber was considered the limit of the weight with which an ordinary soldier could normally be controlled.
The gun had rather high characteristics, a fragmentation projectile weighing 10.6 kg was accelerated in a barrel with a length of 4.5 m to 823 m / s. That ensured an altitude reach of more than 10,000 m. The weight of the gun in the firing position was 8618 kg.
90-mm anti-aircraft gun M1
The M1 antiaircraft gun made an excellent impression, but was difficult to manufacture, and not the gun itself, but the frame of the same design as that of the 76.2 mm M3 gun. It was towed on a single-axle undercarriage with dual pneumatic tires on each side. In the combat position, it stood on a cruciform support, and the crew was located around the gun on a folding platform. The process of folding all the elements of the bed and platform onto a single-axle chassis was very difficult.
In May 1941, the main serial modification of the M1A1 appeared, it had an electric servomotor and a sight with a computer, and according to its signals, the horizontal guidance and elevation angle could be set automatically. In addition, the gun had a spring rammer to increase the rate of fire. But the rammer's design was not very successful, and the gunners usually dismantled it.
In the middle of 1941, the development of a 90-mm anti-aircraft gun began, which, in addition to firing at air targets, was supposed to serve as a coastal defense weapon. This meant a complete overhaul of the bed, because on the previous bed, the barrel could not drop below 0 °. And this opportunity was used for a radical revision of the entire design. The new model of the 90 mm M2 anti-aircraft gun, released in 1942, was completely different, with a low firing table resting on four support beams when firing. The weight of the gun in the firing position was reduced to 6,000 kg.
90-mm anti-aircraft gun M2
With the new bed, the crew became much easier to manage; her preparation for battle was accelerated, and a small armor shield appeared on some models. However, the main changes were made to the design of the gun: the M2 model already had 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.
To adjust the fire of the anti-aircraft battery, the SCR-268 radar was used. 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 °.
Radar SCR-268
The radar detected explosions in the air of medium-caliber anti-aircraft artillery shells, adjusting the fire relative to the target. This was especially important 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. According to American documents, under the Lend-Lease agreement, 25 SCR-268s were sent to the USSR, complete with anti-aircraft batteries.
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.
By August 1945, the American industry had produced 7831 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. 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 aiming and shooting could be controlled remotely. 90-mm guns were also used to create the M36 tank destroyer on the chassis of the Sherman medium tank. This SPG was actively used in battles in northwestern Europe from August 1944 until the very end of the war. The M36 tank destroyer, thanks to its powerful long-barreled 90-mm cannon, turned out to be the only American ground vehicle capable of effectively fighting heavy Wehrmacht tanks, since the M26 Pershing tank, armed with the same cannon, entered the army much later than the M36 - almost to the very end of the war.
In 1928, the 105-mm M3 anti-aircraft gun, created on the basis of a universal naval gun, was adopted. It could fire 15 kg projectiles at air targets flying at an altitude of 13,000 m. The rate of fire of the gun was 10 rds / min.
105-mm anti-aircraft gun M3
By the time of the adoption of the aircraft, flying at such an altitude, there were not yet. These guns have not lost their relevance by the time the Second World War began. But due to the lack of interest in the American military in anti-aircraft artillery systems, they were released in extremely small quantities, only 15 guns. All of them are installed in the Panama Canal area.
Shortly before the start of the war in the United States, work began on the creation of a 120-mm anti-aircraft gun. This gun became the heaviest in the line of American anti-aircraft guns during World War II and was intended to complement the family of lighter and mobile 90-mm M1 / M2 anti-aircraft guns.
120-mm anti-aircraft gun M1
The 120-mm M1 anti-aircraft gun was ready already in 1940, but began to enter the troops only in 1943. A total of 550 guns were produced. The M1 had excellent ballistic characteristics and could hit air targets with a 21 kg projectile at an altitude of 18,000 m, producing up to 12 rounds per minute. For such high performance it was called "stratospheric gun".
The weight of the gun was also impressive - 22,000 kg. The gun was transported on a cart with twin wheels. Served by his calculation of 13 people. When firing, the 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 located near vital objects.
Radar SCR-584
For targeting and anti-aircraft fire control, the SCR-584 radar was used. This radar station, operating in the 10 cm radio frequency range, could detect targets at a distance of 40 km. And to adjust the anti-aircraft fire at a distance of 15 km. The use of the 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 medium and high altitudes even at night.
But for all their merits, these anti-aircraft guns were very limited in mobility. For their transportation, special tractors were required. Transportation speed on paved roads did not exceed 25 km / h. Off-road transportation even with the most powerful tracked tractors was extremely difficult. In this regard, the use of 120-mm anti-aircraft guns in the Pacific theater of operations was extremely limited.
As a result, most of these weapons remained within the borders of the United States. They were deployed along the American West Coast to defend against anticipated Japanese airstrikes that never materialized. About fifteen 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.
Assessing the American anti-aircraft artillery as a whole, one can note the rather high characteristics of anti-aircraft systems produced in wartime. American engineers were able to create almost from scratch, in a short period of time, the entire line of anti-aircraft guns - from small-caliber rapid-fire to "stratospheric" heavy anti-aircraft guns. The US industry fully satisfied the needs of the armed forces in anti-aircraft guns. Moreover, anti-aircraft guns, especially small-caliber ones, were supplied in significant quantities to the allies in the anti-Hitler coalition. So, 7944 anti-aircraft guns were delivered to the USSR. Of these: 90-mm M1 cannons - 251 pcs., 90-mm M2 cannons - 4 pcs., 120-mm M1 cannons - 4 pcs. All the rest are 20mm Oerlikon and 40mm Bofors. The deliveries to the UK were even larger.
At the same time, in the US armed forces, anti-aircraft guns played a significant role only in the Pacific theater of operations. But even there, naval anti-aircraft guns most often fired on Japanese aircraft.
Marine universal medium-caliber anti-aircraft artillery and small-caliber anti-aircraft guns were the last barrier on the way of attacking transports and warships of Japanese aircraft.
If at the beginning of the war dive bombers and torpedo bombers posed a threat to the American fleet, then at the final stage these were aircraft equipped to fly in one direction with a suicide pilot in the cockpit.
In Europe, after the landing of the Allied forces in Normandy, German combat aircraft were aimed mainly at countering the destructive raids of American and British bombers. And in the conditions of complete air supremacy of allied fighters, it did not pose a big threat to ground units. Much more often the American anti-aircraft crews accompanying the advancing troops had to support their infantry and tanks with fire than to repulse the attacks of the German attack aircraft.
