Type 5 15 cm AA Gun
Encyclopedia
The was a large caliber
anti-aircraft gun developed by the Imperial Japanese Army
during the final days of World War II
. It was intended to replace the earlier Type 3 12 cm AA Gun
in civil defense
against American air raids
.
, the Army Technical Bureau developed a larger version with superior range, designated the Type 3. It was one of the few weapons in the Japanese inventory capable of reaching the USAAF B-29 Superfortress
bombers that were attacking cities and other targets in the Japanese home islands. However, by late 1943 it became apparent that the B-29 was capable of flying at altitudes in excess of 10,000 meters, beyond the effective ceiling of the Type 3 12 cm gun.
An emergency project was initiated in December 1943 to address this issue. To save time, the existing Type 3 design was scaled up to 15 centimeters in caliber
, with a corresponding increase in range and firepower. The project was completed relatively quickly, with test guns ready for firing 17 months after the project starting. However by this point it was already too late — all major Japanese cities had been destroyed by the strategic bombing campaign
against Japan, and American bombers were moving onto secondary targets. Japan lacked the raw materials and industrial infrastructure to follow through with mass production. Only two units of the powerful new Type 5 were completed before the surrender of Japan
. One unit each was produced by the Army’s Osaka Arsenal and by Japan Steel Works
.
with sliding breech
, mounted on a central pedestal. The guns were not mobile, requiring deployment in fixed positions.
and against the perceived threat of Allied invasion
. These two guns were deployed to Kugayama, Suginami ward
in the outskirts of Tokyo
. In a single engagement on 1 August 1945 they brought down two B-29 Superfortress
bombers. American bombing raids, however, avoided Kugayama after the incident and as a result the guns had no subsequent chance to fire.
The guns were deployed with a dedicated Type 2 electronic fire control system, with an above ground optical tracker and a targeting computer installed in a nearby bunker, this was linked electronically to the gun's fire control director, allowing precise target tracking.
Caliber
In guns including firearms, caliber or calibre is the approximate internal diameter of the barrel in relation to the diameter of the projectile used in it....
anti-aircraft gun developed by the Imperial Japanese Army
Imperial Japanese Army
-Foundation:During the Meiji Restoration, the military forces loyal to the Emperor were samurai drawn primarily from the loyalist feudal domains of Satsuma and Chōshū...
during the final days of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. It was intended to replace the earlier Type 3 12 cm AA Gun
Type 3 12 cm AA Gun
The was an anti-aircraft gun used in quantity by the Imperial Japanese Army during World War II. It replaced the earlier Type 88 75 mm AA Gun in Japanese service.-History and development:...
in civil defense
Civil defense
Civil defense, civil defence or civil protection is an effort to protect the citizens of a state from military attack. It uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery...
against American air raids
Air raids on Japan
During World War II the Allied forces conducted many air raids on Japan which caused extensive destruction to the country's cities and killed over 300,000 people. These attacks began with the Doolittle Raid in mid-April 1942, but did not resume until June 1944 when United States Army Air Forces ...
.
History and development
In order to address the shortcomings of the Type 88 75 mm AA GunType 88 75 mm AA Gun
The was an anti-aircraft gun used by the Imperial Japanese Army during the Second Sino-Japanese War and World War II. It replaced the earlier Type 11 75 mm AA Gun in front line combat service, and at the time was equal in performances to any of its contemporaries in western armies and was...
, the Army Technical Bureau developed a larger version with superior range, designated the Type 3. It was one of the few weapons in the Japanese inventory capable of reaching the USAAF B-29 Superfortress
B-29 Superfortress
The B-29 Superfortress is a four-engine propeller-driven heavy bomber designed by Boeing that was flown primarily by the United States Air Forces in late-World War II and through the Korean War. The B-29 was one of the largest aircraft to see service during World War II...
bombers that were attacking cities and other targets in the Japanese home islands. However, by late 1943 it became apparent that the B-29 was capable of flying at altitudes in excess of 10,000 meters, beyond the effective ceiling of the Type 3 12 cm gun.
An emergency project was initiated in December 1943 to address this issue. To save time, the existing Type 3 design was scaled up to 15 centimeters in caliber
Caliber
In guns including firearms, caliber or calibre is the approximate internal diameter of the barrel in relation to the diameter of the projectile used in it....
, with a corresponding increase in range and firepower. The project was completed relatively quickly, with test guns ready for firing 17 months after the project starting. However by this point it was already too late — all major Japanese cities had been destroyed by the strategic bombing campaign
Air raids on Japan
During World War II the Allied forces conducted many air raids on Japan which caused extensive destruction to the country's cities and killed over 300,000 people. These attacks began with the Doolittle Raid in mid-April 1942, but did not resume until June 1944 when United States Army Air Forces ...
against Japan, and American bombers were moving onto secondary targets. Japan lacked the raw materials and industrial infrastructure to follow through with mass production. Only two units of the powerful new Type 5 were completed before the surrender of Japan
Surrender of Japan
The surrender of Japan in 1945 brought hostilities of World War II to a close. By the end of July 1945, the Imperial Japanese Navy was incapable of conducting operations and an Allied invasion of Japan was imminent...
. One unit each was produced by the Army’s Osaka Arsenal and by Japan Steel Works
Japan Steel Works
is a steel manufacturer founded in Muroran, Hokkaidō, Japan in 1907.-History:Japan Steel Works was set up with investment from British firms Vickers and Armstrong Whitworth. During World War II, they manufactured what was then the world's largest gun barrel to be fitted on the battleship Yamato...
.
Design
The Type 5 15 cm AA gun had a single piece Gun barrelGun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....
with sliding breech
Breech-loading weapon
A breech-loading weapon is a firearm in which the cartridge or shell is inserted or loaded into a chamber integral to the rear portion of a barrel....
, mounted on a central pedestal. The guns were not mobile, requiring deployment in fixed positions.
Combat record
Coming into service at the end of the war, the two Type 5s completed were retained on the home islands as part of the bolstering of Japan's defenses against Allied air raidsAir raids on Japan
During World War II the Allied forces conducted many air raids on Japan which caused extensive destruction to the country's cities and killed over 300,000 people. These attacks began with the Doolittle Raid in mid-April 1942, but did not resume until June 1944 when United States Army Air Forces ...
and against the perceived threat of Allied invasion
Operation Downfall
Operation Downfall was the Allied plan for the invasion of Japan near the end of World War II. The operation was cancelled when Japan surrendered after the atomic bombing of Hiroshima and Nagasaki and the Soviet Union's declaration of war against Japan. The operation had two parts: Operation...
. These two guns were deployed to Kugayama, Suginami ward
Suginami, Tokyo
is one of the 23 special wards of Tokyo, Japan. In English, it calls itself Suginami City.As of April 1, 2011, the ward has an estimated population of 538,703, with 301,277 households, and a density of 15,834.39 persons per km². The total area is 34.02 km².-Geography:Suginami occupies the...
in the outskirts of Tokyo
Tokyo
, ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...
. In a single engagement on 1 August 1945 they brought down two B-29 Superfortress
B-29 Superfortress
The B-29 Superfortress is a four-engine propeller-driven heavy bomber designed by Boeing that was flown primarily by the United States Air Forces in late-World War II and through the Korean War. The B-29 was one of the largest aircraft to see service during World War II...
bombers. American bombing raids, however, avoided Kugayama after the incident and as a result the guns had no subsequent chance to fire.
Effectiveness
A postwar American report evaluated the effectiveness of Japanese anti-aircraft fire. The report demonstrated that the Type 5 15 cm AA gun was more than five times more effective than the Type 3 12 cm AA gun, and that the engagement envelope was considerably larger.| Item | 7 cm AA | 8 cm AA | 12 cm AA | 15 cm AA |
|---|---|---|---|---|
| Time to fire four shells | 6 s | 6 s | 12 s | 18 s |
| Radius of rupture | 5 m | 7 m | 15 m | 30 m |
| Volume of rupture | 1 m3 | 2.7 m3 | 27 m3 | 215 m3 |
| Weight of shell | 5.3 kg | 7.4 kg | 19.3 kg | 41 kg |
| Ratio of volume rupture × rate of fire (7 cm as baseline) |
1 | 2.7 | 13.5 | 71.6 |