Type-89 12.7 cm cannon
| Type-89 12.7 cm cannon | |
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| General Information | |
| Military designation: | 四 〇 口径 八九 式 十二 糎 七 高 角 砲 |
| Manufacturer country: |
 Japan
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| Developer / Manufacturer: | Kure and Hiroshima marine workshops |
| Development year: | 1929-1932 |
| Production time: | 1932 to 1945 |
| Number of pieces: | 1300 |
| Weapon Category: | Anti-aircraft gun |
| Team: | 11 for twin mounts |
| Technical specifications | |
| Pipe length: | 5.08 m |
| Caliber : |
12.7 cm |
| Caliber length : | L / 40 |
| Number of trains : | 36 |
| Twist : | clockwise |
| Weight ready for use: | Type 89 A1 20,300 kg Type 89 A1 Mod.3 29,000 kg Type 88 8,800 kg |
| Cadence : | maximum 14 normal 8 rounds / min |
| Elevation range: | −8 ° to +90 degrees |
| Side straightening area: | 360 |
The Type 89 12.7-cm-L / 40 ( Japanese. 四 〇 口径 八九 式 十二 糎 七 高 角 砲 ) was an anti-aircraft gun that was used by the Imperial Japanese Navy during World War II . The designation Type 89 indicates the year of the first development, the year Kōki 2589 or 1929 according to the Gregorian calendar .
history
The Type 89 was developed in 1929 as a replacement for the 8 cm L / 40 Type 3 anti-aircraft gun, which was used on battleships and cruisers of the Imperial Navy for air defense over long distances. The 8 cm L / 40 was loaded by hand and had a correspondingly low cadence . The new weapon should have an automatic loading ram that pushed the projectiles from a loading arm into the gun.
The situation was similar with the 12 cm L / 45 year 10 in single mounts, which initially formed the anti-aircraft armament for the heavy cruisers of the Imperial Japanese Navy and which were also installed on large ships such as the Akagi , but also had to be replaced.
The 12.7 cm L / 50 gun from 1927, which was used as the main armament on destroyers of the Fubuki and Yūgumo class , had nothing to do with the new development of the anti-aircraft gun , apart from the caliber, because the destroyer gun was no success because of its low rate of only five rounds per minute. Propellant charge and projectile had to be loaded separately here.
technology
The Type 89 gun weighed 3.15 tons with breech block and was 5.28 meters long. The gun barrel was made from a block into which the barrel had been drilled afterwards. In the inside of the barrel 36 right-turning trains with a full turn were milled to 28 caliber lengths (3.56 meters). The gun was equipped with a block lock and could fire various types of shells weighing between 20 and 24 kg with a muzzle velocity of up to 720 meters per second.
Mount
Structure and functionality
The twin mounts of the Type 89 carried two 12.7 cm guns mounted parallel to the axis. The carriage was operated electro-hydraulically, so it needed electricity from a generator to be moved. The motors of the mount could, depending on the model used, increase or decrease the straightening angle of the pipes at a speed of up to 16 ° per second and swivel the mount to the left or right at the same speed. Elevation angles between −8 ° and + 90 ° could be achieved in this way.
The grenades were transported from inside the ship with conveyor belts to the vicinity of each carriage. Depending on the ship, this delivery system achieved an output of ten shells per minute, so it was comparatively slow. The grenades were then carried by hand to the gun and then placed in a loading arm. The platform from which the grenades were placed in the rocker arm rose and fell according to the directional angle of the weapon, so that the loading process was still easy to carry out even at a directional angle of + 80 °.
The deflectors for the ejected bullet cases also moved in accordance with the aiming angle of the weapon. While the deflector was deflected downwards with an almost horizontal alignment, the position of the deflectors changed at high straightening angles so that the sleeves were not thrown against the mechanism of the carriage.
The station for setting the time fuse was on the right side of the mount . The soldier in charge changed the setting on the detonator of the grenades that were to be loaded next, while they were located directly behind the breech of the weapon in the loading arm. The soldier read the distance at which the grenade was to explode from a display that received its data from the fire control system. He then changed the timing of the detonators with a handwheel, the rotation of which was transmitted via a rod to two grippers above the grenades, which then reached into the rings of the two time detonators at the tip of the grenade and set them so that the charges were in the Grenades exploded after a fixed flight time between 0 and 35 seconds.
team
The twin carriage of the Type 89 was operated by eleven soldiers:
- a shooter for the height direction of the weapon
- a contactor for the lateral direction of the mount
- a contactor for setting the detonators
- two loaders (one per gun)
- six ammunition carriers (three per gun)
Sight and fire control
Function of the visor
Each mount had a telescope on the left side for sighting targets. While the guns, which were intended as pure anti-aircraft weapons, were not normally aimed directly, but rather the two soldiers who were responsible for aligning the weapon simply followed the instructions given by the fire control device, they could also use the optics to direct a target .
Fire control
Initially, groups of Type 89 guns were coordinated with the Type 91 fire control system developed in 1929.
During the Pacific War, the 12.7 cm Type 89 anti-aircraft guns were mostly controlled with the Type 94 fire control unit 高 射 装置 Kosha Sochi from 1934 on large warships . The fire control device could be used to set barrages at certain heights and distances with the anti-aircraft cannons, or to target individual targets while flying straight ahead. Aircraft that changed altitude and course, however, could not be targeted.
When fighting individual targets that were flying with the same course and constant speed, the target was sighted through an observation periscope and the angle between the ship, horizon and target was determined. The distance to the target was measured using an optical rangefinder with a base length of 4.5 meters. An integration of radar data for distance measurement was not planned.
The angle and distance were entered into a mechanical computing device with the data on the estimated speed of the target and the ship's own speed, which then continuously calculated the values for the alignment of the anti-aircraft guns and the setting of the time fuses for the grenades and transmitted them to the gun commanders. The command to fire was adapted to the rolling movements of your own ship.
The fire control system required ten soldiers to collect the observation data from each rangefinder, and another nine men operated the computing device.
In individual cases were type 89 - batteries , however, also be used on land to defend cities and important installations. To defend Kure against attacks by Boeing B-29 bombers at the end of the war, five batteries, each with three Type 89 twin mounts, were placed on the surrounding hills. They were controlled by the Raiun fire control system (German for "thundercloud"), which was developed to direct the maximum possible number of projectiles into a specific three-dimensional target area in a short time.
Other uses than land-based weapons are mentioned, for example, in the defense of the island of Pohnpei , where Type 89 guns were installed in concrete ring positions for anti-aircraft defense.
ammunition
The ammunition for the Type 89 anti-aircraft cannon consisted of a brass case with a 4 kg propellant charge and the projectile:
- The Model 3 standard high explosive fragmentation grenade with a Type 4 Model 1 time fuse was the type of grenade that was used for air defense until the introduction of the high explosive incendiary grenade . The maximum height the grenade could reach was 9,418 meters. The radius within which the fragments could still cause enough damage after the grenade exploded to damage or destroy an aircraft was almost 19 meters.
Further types of projectiles were developed by the Navy to enable additional types of use of the guns:
- Model 3 high-explosive incendiary grenade, with a Type 4 Model 1 time fuse. The grenade was 437 mm long, weighed 23 kg and contained 66 stick incendiary bombs, each of which was 5 cm long and 2 cm in diameter. It was introduced in 1944 and its structure corresponded to the projectiles that had been developed at the same time for the main armament of larger ships. However, the effectiveness of the stick incendiary bombs released by the shells in repelling enemy aircraft is controversial.
- Anti-submarine grenade, with a weight of 21 kg, a muzzle velocity of 250 m / s and a range of 4300 meters. The grenade was developed to penetrate a steel plate 2.5 cm thick at a depth of eight meters. In theory, eight meters was enough to hit a submarine moving at periscope depth. This type of shell was probably not intended for the guns on large ships, but rather for escort ships whose tasks included hunting submarines.
- Flare grenade with the designation Type B , with a Type 4 Model 1 time fuse. This grenade contained a flare, which was released on a small parachute after the time set on the detonator and then slowly floated to the ground. The brightness generated was around 667,000 cd .
Models
There were three variants of the Type 89 anti-aircraft gun. While the majority of the weapons were produced in the variant as twin mounts, there were two variants of the weapon as single mounts.
The Type 89 cannon on a twin mount was the standard type of weapon. Different models of twin mounts were produced, but they differed only in the different types of protective attachments for the operating team and different motors for straightening the mount. Real armor protection, which protected the crew from direct fire, was not intended - only a 2 mm thick splinter protection was installed on some mounts.
- Type 89 A1 only had a protective shield for the gunner on the left side of the mount and a small shack on the right side for the soldier who controlled the setting of the time fuse. The carriage weighed 20.3 tons and was the standard version that was installed on the majority of the ships with Type 89 guns. It had motors that could move the mount horizontally at 6 ° per second and raise or lower the guns at 12 ° per second.
- Type 89 A1 Model 1 had a splinter guard that was extended for the crew by a deflector for chimney exhaust gases and weighed 24.5 tons. It was used on cruisers of the Mogami , Myōkō and Tone class .
- Type 89 A1 Model 2 had a closed housing to protect the crew from chimney exhaust fumes and was intended for use on aircraft carriers that did not discharge their exhaust fumes upwards but out of the ship at the sides.
- Type 89 A1 Model 3 was completely enclosed by a pressure wave shield to protect the crew from the pressure created when firing the 46 cm main armament on battleships of the Yamato class . The A1 Model 3 was accordingly the heaviest carriage at 29 tons and was used exclusively on the battleships of the Yamato class.
- Type 89 B1 was a development for destroyers of the Matsu class and stood there on the stern.
- Type 89 B2 was equipped with a more powerful electric motor and could swivel the mount by 16 ° in one second and change the tube elevation just as quickly.
The version of the weapon on a single mount was built to a small extent in two variants:
- The Type 88 cannon was optimized for use on submarines and consisted of a single mount and a gun, the components of which were designed in such a way that corrosion from salt water was largely prevented. The gun had been developed in 1928 and weighed 8.8 tons with its mount, but did not have the automatic loading device and the electric directional motors of the Type 89 . It was installed on submarines I-5 and I-6 as a deck gun.
- The Type 89 B1 Model 4 cannon as a single mount , without the adaptation for submarine use, but with an automatic loading aid, was also produced on a small scale in order to be used as armament for the destroyers of the Matsu class, which began late in the war to act. The mount was completely enclosed by a protective shield that was open to the rear.
today
A Type 89 single mount from a Matsu-class destroyer is set up in Etajima next to the replica turret of the battleship Mutsu .
Evidence and references
Remarks
- ↑ The penetration rate is given in the O-19 document as 25 cm, but is corrected to 2.5 cm in other sources, such as navweaps.com.
Individual evidence
- ↑ USNTMJ O-47 p. 41.
- ↑ USNTMJ O-47 p. 19.
- ↑ USNTMJ O-30 p. 67 f.
- ↑ USNTMJ O-30 p. 33 and following
- ^ Duane "Colt" Denfeld: Field survey of Ponape: World War II features. Micronesian archeological survey reports, Office of Historic Preservation, Trust Territory of the Pacific Islands, December 1979, p. 91.
- ↑ USNTMJ O-19 p. 9.
- ↑ USNTMJ O-19 p. 17.
- ↑ a b USNTMJ O-47 p. 17.
literature
- REPORTS OF THE US NAVAL TECHNICAL MISSION TO JAPAN 1945-1946, O-47, Japanese Naval Guns and Mounts-Article 1, Mounts Under 18 ”, 1946
- REPORTS OF THE US NAVAL TECHNICAL MISSION TO JAPAN 1945–1946, O-19, Japanese Projectiles General Types, 1946
- Escort destroyer of the Matsu class - warships in quick build (松 型 駆 逐 艦 - 簡易 設計 な が ら 生存 性 に 秀 で た 戦 時 急 造 艦 の 奮 戦), Pacific War - Volume 43, Gakken, 2003, ISBN 4-05-603251-3
- Eric LaCroix, Linton Wells: Japanese Cruisers of the Pacific War. US Naval Institute Press, 1997, ISBN 0-87021-311-3 .
