During the air raids of the American B-29 Superfortress heavy bombers on the Japanese islands, it turned out that if they flew at high altitudes, then the main part of the Japanese anti-aircraft guns could not reach them. In the course of the war, the Japanese tried to create new large-caliber anti-aircraft guns with a long reach, and also to use versatile naval guns with high ballistic characteristics against the Superfortresses. However, despite the sporadic successes, the Japanese anti-aircraft artillery was never able to effectively resist the destructive bombing of Japanese cities.
Japanese 75-76 mm anti-aircraft guns
The British 76-mm QF 3-inch 20 cwt anti-aircraft gun, which, in turn, was created on the basis of the Vickers QF three-inch naval gun, had a great influence on the appearance and design of the first Japanese 75-mm Type 11 anti-aircraft gun.
The Type 11 gun, which was put into service in 1922 (the 11th year of the reign of Emperor Taise), had satisfactory characteristics for that time. Its mass in a combat position was 2060 kg. A shrapnel 6, 5 kg projectile in a barrel 2562 mm long accelerated to 585 m / s, which ensured an altitude reach of 6500 m. Vertical guidance angles: 0 ° to + 85 °. Combat rate of fire - up to 15 rds / min. Calculation - 7 people.
The 75 mm Type 11 anti-aircraft gun was not widely used in the imperial army. In the late 1920s - early 1930s, there was no particular need for it, and in the second half of the 1930s, due to the rapid growth in the characteristics of combat aircraft, it was hopelessly outdated. In addition, the first Japanese 75mm anti-aircraft gun proved to be difficult and expensive to manufacture, and its production was limited to 44 copies.
English-language sources claim that by the time of the Japanese attack on Pearl Harbor, the Type 11 guns had already been removed from service. However, given the fact that the Japanese army has traditionally experienced a shortage of medium-caliber artillery systems, such a statement seems doubtful.
Judging by the available photographs, the obsolete 75-mm anti-aircraft guns were not removed from service, but used in coastal defense. At the same time, they retained the ability to conduct defensive anti-aircraft fire with regular shells.
In 1908, Japan acquired a license from the British firm Elswick Ordnance to manufacture the 76-mm QF 12-pounder 12-cwt gun. The gun, modernized in 1917, was designated Type 3.
This gun, thanks to the increase in the vertical aiming angle to + 75 °, was able to conduct anti-aircraft fire. For firing, fragmentation or shrapnel shells weighing 5, 7–6 kg, with an initial speed of 670–685 m / s were used. The altitude reach was 6800 m. The rate of fire was up to 20 rds / min. In practice, due to the lack of fire control devices and centralized guidance, the effectiveness of anti-aircraft fire was low, and these guns could only conduct defensive fire. Nevertheless, the 76-mm Type 3 cannons served on the decks of auxiliary ships and in coastal defense until the end of World War II.
Japanese experts were aware that the Type 11 gun did not fully meet modern requirements, and already in 1928, the 75-mm Type 88 anti-aircraft gun was presented for testing (2588 "from the founding of the empire").
Although the caliber of the new gun remained the same, it was superior in accuracy and range to its predecessor. The mass of the Type 88 in the combat position was 2442 kg, in the stowed position - 2750 kg. With a barrel length of 3212 mm, the initial velocity of a projectile weighing 6, 6 kg was 720 m / s. Reach in height - 9000 m. In addition to a fragmentation grenade with a remote fuse and a high-explosive fragmentation projectile with a shock fuse, the ammunition load included an armor-piercing projectile weighing 6, 2 kg. Having accelerated to 740 m / s, at a distance of 500 m along the normal, an armor-piercing projectile could penetrate 110 mm thick armor. Rate of fire - 15 rounds / min.
The Type 88 gun was transported on a detachable single-axle wheel drive, but for the calculation of 8 people, the process of transferring the 75-mm anti-aircraft gun from the traveling position to the combat position and back was a very difficult task. Particularly inconvenient for deploying anti-aircraft guns in a combat position was such a structural element as a five-beam support, in which it was necessary to move four heavy beds apart and unscrew five jacks. Dismantling and installation of two transport wheels also took a lot of time and effort from the crew.
Against the background of peers, the 75-mm Type 88 anti-aircraft gun looked good. But by the beginning of the 1940s, with an increase in speed, and especially in the flight altitude of new bombers, it could no longer be considered modern. Until early 1944, about half of the more than 2,000 anti-aircraft guns were deployed outside the metropolis.
In addition to their direct purpose, the Type 88 guns were actively used in the antiamphibious defense of the islands. Faced with a shortage of effective anti-tank weapons, the Japanese command began to deploy 75-mm anti-aircraft guns in the tank-hazardous areas. Since deployment to a new location was difficult, the guns were most often in prepared stationary positions. However, shortly after the first raids of the Superfortresses, most of the Type 88 guns were returned to Japan.
In the course of repelling the attacks of the B-29, it turned out that in most cases, taking into account the inclined range, Type 88 anti-aircraft guns can fire at targets flying at an altitude of no more than 6500 m. In the daytime, over the bombing targets, well covered by anti-aircraft artillery, the pilots of American bombers tried to operate outside the effective anti-aircraft fire zone. At night, when the aircraft carrying "lighters" in cluster bombs dropped to 1500 m, the 75-mm anti-aircraft guns had a chance to hit the "Superfortress". But given the fact that the Japanese had very few anti-aircraft gun control radars, anti-aircraft artillery, as a rule, conducted barrage fire.
In 1943, the 75-mm Type 4 anti-aircraft gun entered service. It was actually an unlicensed copy of the 75-mm Bofors M30 anti-aircraft gun, copied from anti-aircraft guns captured from the Dutch.
Compared to the Type 88, the Type 4 gun was a much more advanced and easy-to-use model. The mass in the combat position was 3300 kg, in the stowed position - 4200 kg. Barrel length - 3900 mm, muzzle velocity - 750 m / s. Ceiling - up to 10,000 m. Vertical guidance angles: –3 ° to + 80 °. A well-trained crew could provide a rate of fire - up to 20 rds / min.
Due to the incessant raids of American bombers and a chronic shortage of raw materials, the production of new 75-mm anti-aircraft guns faced big problems, and only less than a hundred Type 4 guns were produced. All of them were located on the territory of the Japanese islands and for the most part survived to surrender. Despite the higher rate of fire and reach in height, due to their small number, the Type 4 anti-aircraft guns could not significantly increase the capabilities of the Japanese air defense.
Japanese 88 and 100 mm anti-aircraft guns
Japanese troops in the vicinity of Nanjing in 1937 captured German-made 88-mm naval guns 8.8 cm L / 30 C / 08. After careful study, it was decided to create its own 88-mm anti-aircraft gun on the basis of the German gun.
A Japanese 88 mm anti-aircraft gun, designated Type 99, entered service in 1939. To reduce the cost and launch mass production for this gun as soon as possible, the wheel drive was not developed, and all Japanese 88-mm guns were based on stationary positions.
The mass of the Type 99 anti-aircraft gun in the combat position was 6500 kg. In terms of reach and firing range, it was approximately 10% superior to the main Japanese Type 88 75-mm anti-aircraft gun. 88 mm projectile that weighed 9 kg. The Type 99's combat rate of fire was 15 rds / min.
From 1939 to 1945, about 1000 88-mm Type 99 guns were produced, most of them were located on the Japanese islands. The calculations of the guns deployed on the coast were entrusted with the responsibility of repelling enemy landings.
After the adoption of the 75-mm Type 11 anti-aircraft gun, the command of the imperial army showed interest in creating a larger-caliber anti-aircraft gun. The 100mm gun, known as the Type 14 (14th year of the reign of Emperor Taisho), entered service in 1929.
The mass of the Type 14 gun in the firing position was 5190 kg. Barrel length - 4200 mm. The muzzle velocity of a 15 kg projectile is 705 m / s. Ceiling - 10500 m. Rate of fire - up to 10 rds / min. The base of the implement was supported by six paws, which were leveled by jacks. To remove the wheel travel and transfer the gun to the firing position, the crew took 45 minutes.
Taking into account the fact that at the end of the 1920s in Japan there was no effective PUAZO, and the 100-mm gun itself was expensive and difficult to manufacture, after the 75-mm Type 88 anti-aircraft guns were adopted, the Type 14 was discontinued.
In total, about 70 Type 14 guns were produced. During the Second World War, they were all concentrated on the island of Kyushu. The Japanese command deployed the main part of the 100-mm anti-aircraft guns around the metallurgical plant in the city of Kitakyushu.
Due to the acute shortage of anti-aircraft guns capable of reaching B-29s flying at close to maximum altitude, the Japanese actively used naval guns. In 1938, a closed twin turret 100-mm gun mount Type 98 was created, with which it was planned to equip new destroyers. The operation of the installations began in 1942.
A semi-open Type 98 Mod was developed to arm large ships such as the cruiser Oyodo, aircraft carriers Taiho and Shinano. A1. The weight of the installation intended for the Akizuki-class destroyers was 34,500 kg. Semi-open units were about 8 tons lighter. The mass of one gun with a barrel and breech is 3053 kg. An electro-hydraulic drive guided the installation in the horizontal plane at a speed of 12–16 ° per second and vertically up to 16 ° per second.
A shrapnel shell weighing 13 kg contained 0.95 kg of explosives. And during an explosion, it could hit air targets within a radius of up to 12 m. With a barrel length of 65 klb. the initial speed was 1010 m / s. Effective firing range at air targets - up to 14,000 m, ceiling - up to 11,000 m. Rate of fire - up to 22 rds / min. The flip side of the high ballistic characteristics was the low barrel survivability - no more than 400 shots.
The 100-mm Type 98 gun mount is one of the best dual-use artillery systems created in Japan. And it turned out to be very effective when shooting at aerial targets. At the beginning of 1945, guns intended for unfinished warships were installed on coastal stationary positions. These were the few Japanese anti-aircraft artillery systems capable of effectively countering the B-29. Of the 169 100-mm twin turrets produced by the industry, 68 were placed in fixed land positions.
Due to the reduced weight and lower cost, only semi-open installations were permanently mounted on the shore. Several Type 98 Mod. A1s stationed in Okinawa were destroyed by shelling from the sea and airstrikes.
Japanese 120-127 mm anti-aircraft guns
Due to the acute shortage of specialized anti-aircraft guns, the Japanese actively adapted naval guns for firing at air targets. A typical example of this approach is the 120mm Type 10 universal gun, which entered service in 1927 (10th year of the reign of Emperor Taisho). This gun is a further development of the Type 41 120 mm naval gun, known in the West as the 12 cm / 45 3rd Year Type naval gun, which traces its origins to the British 120 mm / 40 QF Mk I naval gun.
According to American data, about 1000 Type 10 guns were placed on the shore. In total, more than 2,000 of these guns were produced in Japan.
The mass of the gun in the firing position was 8500 kg. The barrel with a length of 5400 mm provided 20.6 kg of the projectile with an initial speed of 825 m / s. Reach in height was 9100 m. Vertical guidance angles: from –5 ° to + 75 °. Rate of fire - up to 12 shots / min.
Although by 1945 the 120-mm Type 10 guns were already considered obsolete and did not fully meet modern requirements, until the surrender of Japan, they were actively used for defensive anti-aircraft fire.
The Japanese command understood the weakness of the 75-mm anti-aircraft guns. In this connection, in 1941, a technical assignment was issued for the design of a new 120-mm gun. In 1943, production of the Type 3 gun began.
The 120mm Type 3 gun was one of the few Japanese anti-aircraft guns capable of reaching the Super Fortresses traveling at maximum altitude. In the range of elevation angles from + 8 ° to 90 °, the gun could fire at targets flying at an altitude of 12000 m, within a radius of up to 8500 m from the anti-aircraft position. Or flying at an altitude of 6000 m at a distance of 11000 m. Rate of fire - up to 20 rds / min. Such characteristics still inspire respect. However, the mass and dimensions of the 120-mm anti-aircraft gun were also very impressive: the weight was 19,800 kg, the barrel length was 6,710 mm.
The gun fired with a 120x851 mm unitary shot. The mass of a fragmentation grenade with a remote fuse is 19.8 kg. American reference books say that the explosion of a 120-mm anti-aircraft projectile produced more than 800 lethal fragments with a radius of destruction of air targets up to 15 m. Various sources also indicate that the muzzle velocity of a 120-mm Type 3 projectile was 855-870 m / s.
All Type 3 anti-aircraft guns were deployed in stationary, well-trained positions around Tokyo, Osaka and Kobe. Some of the guns were equipped with anti-fragmentation armor, which protected the crews from the front and rear. Some Type 3 anti-aircraft batteries were mated with anti-aircraft fire control radars, which made it possible to aim at targets that were not visually observed in the dark and in thick cloud conditions.
The calculations of 120-mm Type 3 guns managed to shoot down or seriously damage about 10 B-29 bombers. Fortunately for the Americans, the number of these anti-aircraft guns in Japan's air defense was limited. By January 1945, it was planned to deliver at least 400 new 120-mm guns. But the lack of production capacity and raw materials, as well as the bombing of Japanese factories did not allow reaching the planned volumes. Until August 1945, it was possible to release approximately 120 anti-aircraft guns.
One of the most common artillery pieces in the Japanese navy was the 127mm Type 89. This unitary loading cannon, adopted in 1932, was developed from the 127mm Type 88 submarine gun.
The Type 89 guns were mainly mounted in twin mounts, which were used as main guns on destroyers of the Matsu and Tachibana types, they also served as versatile artillery on cruisers, battleships and aircraft carriers.
The gun had a simple design with a monoblock barrel and a horizontal sliding bolt. According to experts, the characteristics of the Japanese 127-mm Type 89 were close to the American 5-inch Mark 12 5 ″ / 38 naval gun. But American ships had a more advanced fire control system.
A unitary shot with dimensions of 127x580 mm was used for firing. With a barrel length of 5080 mm, a projectile weighing 23 kg accelerated to 725 m / s. The maximum vertical reach was 9400 m, and the effective reach was only 7400 m. In the vertical plane, the installation was directed in the range from –8 ° to + 90 °. The gun could be loaded at any elevation angles, the maximum rate of fire reached 16 rds / min. The practical rate of fire depended on the physical capabilities of the calculation and with prolonged firing usually did not exceed 12 rds / min.
In the period from 1932 to 1945, about 1,500 127-mm guns were produced, of which more than 360 guns were installed in coastal defense batteries, which also fired anti-aircraft fire. Yokosuka (96 guns) and Kure (56 guns) were best covered by 127-mm coastal batteries.
Japanese 150mm anti-aircraft guns
The 150-mm Type 5 is considered to be the most advanced Japanese heavy anti-aircraft gun. This gun could effectively counteract American B-29 bombers at long range and in the entire range of altitudes at which the Superfortresses operated.
The development of the gun began in early 1944. In order to speed up the creation process, Japanese engineers took the 120-mm Type 3 anti-aircraft gun as a basis, increasing it in size. Work on the Type 5 was going fast enough. The first gun was ready to fire 17 months after the start of the project. By this time, however, it was too late. The economic and defense potential of Japan had already been undermined, and large Japanese cities were largely destroyed as a result of carpet bombing. For the mass production of new effective 150-mm anti-aircraft guns, Japan lacked raw materials and industrial infrastructure. Before the surrender of Japan, two Type 5 guns were deployed on the outskirts of Tokyo in the Suginami area.
Due to the very large weight and dimensions of the 150-mm anti-aircraft guns, they could only be placed in stationary positions. Although two guns were ready already in May 1945, they were put into operation only a month later. This was largely due to the novelty of a number of technical solutions and the complexity of the fire control system.
To guide the shooting of the Type 5, Type 2 analog computing equipment was used, receiving information from several optical rangefinder posts and radars. The control center was located in a separate bunker. After processing the information, the data was sent to the gunners' display via cable lines. And the time for the detonation of remote fuses was set.
A 150-mm projectile weighing 41 kg in a barrel 9000 mm long accelerated to 930 m / s. At the same time, the Type 5 gun could effectively deal with targets flying at an altitude of 16,000 m. With a firing range of 13 km, the height reach was 11 km. Rate of fire - 10 shots / min. Vertical guidance angles: from + 8 ° to + 85 °.
If there were more 150-mm guns in the Japanese air defense system, they could inflict heavy losses on American long-range bombers. On August 1, 1945, Type 5 crews shot down two Super Fortresses.
This incident did not go unnoticed by the command of the 20th Air Army, and until the surrender of Japan, the B-29s no longer entered the range of the Japanese 150-mm anti-aircraft guns.
After the end of hostilities, the Americans investigated the incident and carefully studied the Type 5 anti-aircraft guns. The investigation concluded that the new 150-mm Japanese anti-aircraft guns posed a great threat to American bombers. Their efficiency was 5 times higher than that of the 120 mm Type 3, which used optical rangefinders to control fire. A sharp increase in the combat characteristics of 150-mm anti-aircraft guns was achieved thanks to the introduction of an advanced fire control system that processes information from several sources. In addition, the range and height reach of Type 5 guns significantly exceeded all other Japanese anti-aircraft guns, and when a 150-mm fragmentation projectile burst, the radius of destruction was 30 m.
Japanese early warning and anti-aircraft artillery fire control radars
For the first time, Japanese officers and technicians were able to familiarize themselves with the radar for detecting air targets in December 1940, during a friendly visit to Germany. In December 1941, the Germans sent a submarine to deliver the Würzburg radar to Japan. But the boat was lost, and the Japanese managed to obtain only technical documentation, which was delivered by diplomatic mail.
The first Japanese radars were created on the basis of captured British GL Mk II radars and American SCR-268, captured in the Philippines and Singapore. These radars had very good data for their time. So, the SCR-268 radar could see aircraft and correct anti-aircraft artillery fire at explosions at a distance of up to 36 km, with an accuracy of 180 m in a range and an azimuth of 1, 1 °.
But this station turned out to be too complex for the Japanese radio industry. And Toshiba specialists, at the cost of reduced performance, developed a simplified version of the SCR-268, known as the Tachi-2.
The station operated at 200 MHz. Pulse power - 10 kW, target detection range - 30 km, weight - 2.5 tons. In 1943, 25 Tachi-2 radars were produced. However, due to low reliability and unsatisfactory noise immunity, these stations were idle more than they worked.
The British GL Mk II radar was much simpler. In addition, the radio components necessary for it were produced in Japan. The Japanese copy received the designation Tachi-3.
The radar, created by NEC, operated on a wavelength of 3.75 m (80 MHz) and, with a pulse power of 50 kW, detected aircraft at a distance of up to 40 km. The Tachi-3 radar entered service in 1944, more than 100 examples were built.
The next modification of the Japanese clone SCR-268 received the designation Tachi-4. Toshiba engineers have reduced the pulse power of the radar to 2 kW, thus achieving acceptable reliability. At the same time, the detection range decreased to 20 km.
These radars were mainly used to control anti-aircraft artillery fire and target searchlights. Approximately 50 Tachi-4s have been produced since mid-1944.
In mid-1943, production of the Tachi-6 early warning radar began. This radar from Toshiba appeared after studying the American SCR-270 radar. The transmitter of this station operated in the frequency range of 75–100 MHz with a pulse power of 50 kW. It had a simple transmitting antenna, mounted on a pole or tree, and up to four receiving antennas housed in tents and rotating by hand. A total of 350 kits were produced.
In addition to the radars listed, other radars were also produced in Japan, mainly based on American and British models. At the same time, the Japanese clones in most cases did not reach the characteristics of the prototypes. Due to the unstable operation of Japanese radars, caused by low operational reliability, the approaching American bombers in most cases were detected by the radio intercept service, recording conversations between the B-29 crews. However, radio intelligence could not reliably establish which Japanese city was the target of the bombers, and in a timely manner send interceptors there.
Evaluation of the combat effectiveness of Japanese medium and large-caliber anti-aircraft artillery
According to American data, 54 Super Fortresses were shot down by anti-aircraft artillery fire during raids on the Japanese islands. Another 19 B-29 damaged by anti-aircraft guns were finished off by fighters. The total losses of B-29s that took part in combat missions amounted to 414 aircraft, among them 147 aircraft had combat damage.
The technical reliability of the first B-29 engines left much to be desired. Due to the engine that caught fire in flight, American pilots often interrupted the mission. Often, combat damage, superimposed on the failure of technology, led to the death of the bomber.
The Japanese anti-aircraft gunners also have fighters and bombers from the 5th and 7th American air armies. In July-August 1945 alone, these formations lost 43 aircraft from enemy fire. During the raids of the US Navy on objects located on the Japanese islands, air defense forces shot down and seriously damaged about one and a half hundred American carrier-based aircraft. However, the American economy more than compensated for the material losses. Until the end of the war, five aircraft factories located in the United States, the B-29 alone, built more than 3,700 copies.
Despite occasional successes, Japanese anti-aircraft artillery was unable to defend the country from American bombing. This was primarily due to the lack of anti-aircraft guns. Japan's air defense systems covered only large cities, and most of the available anti-aircraft guns were unable to fight the B-29 operating at high altitude during the day. At night, when the Superfortresses were dropping to 1,500 m, the effectiveness of anti-aircraft fire was unsatisfactory due to the lack of shells with a radio fuse and an insufficient number of radars capable of directing fire in the dark. Conducting massive defensive anti-aircraft fire led to the rapid depletion of shells. Already in July 1945, there were cases when Japanese anti-aircraft batteries could not fire, due to the lack of ammunition.
In the conditions of a total shortage of resources, the main customers for weapons and ammunition were the Air Force and the Navy, and the imperial army was mostly content with "crumbs from their table." In addition, most of the anti-aircraft guns had an archaic design and did not meet modern requirements.
The production of new Japanese anti-aircraft guns was carried out at an extremely low rate, and a number of promising developments were never brought to the stage of mass production. For example, in the framework of military-technical cooperation with Germany, detailed technical documentation for modern 88 and 105-mm anti-aircraft guns was received. But due to the weakness of the material base, it was not possible to make even prototypes.
For Japanese anti-aircraft artillery, a variety of guns and ammunition was characteristic, which inevitably created big problems in supply, maintenance and preparation of calculations. Among the leading countries participating in World War II, Japan's ground-based air defense systems turned out to be the smallest and most ineffective. This led to the fact that American strategic bombers could carry out raids with impunity, destroy Japanese cities and undermine industrial potential.
