The Japanese Arsenal.

[CharlesBronson]

Japanese aircraft weapons of WW2.

When somebody really interested in aircraft armament of WW2 make a review of all the different designs emerged during the period of time from 1930 to 1945 the outcome is a somewhat puzzling. First of all the complete and absolute lack of standarization between the Army air Forces and Navy Fleet air Arm is quite evident.
The japanese case remembers a lot to the italian view on air combat, they started the war with nimble light fighters armed mostly with a pair of rifle caliber or heavy machineguns, but later they had to develop cannon armament quickly to deal with armored allied fighters and the ever increasing presence of heavy bombers on their homefront.

To obtain detailed information of every weapon is not an easy task because the dimentions, weights, rate of fire and other figures varied from source to source. Detail of ammunition types and variant are scarce too. Aniway althought not 100% accurate I think is relevant to have a recopilation of all the guns used by this country in the second great world conflict.

 

[tyrodtom]

I just finished a book called Blossoms in the Wind, it was interviews with surviving kamakazi pilots.

According to it Navy bombs wouldn't fit Army aircraft, without several hours of modifications. It didn't go into the technical reason, bomb shackle spacing or what. And this would have been late in the war. The Army and Navy in most countries didn't set very good examples for co-operation, but the Japanese set new standards in interservice rivalry.

 

[CharlesBronson]

I just finished a book called Blossoms in the Wind, it was interviews with surviving kamakazi pilots.

According to it Navy bombs wouldn't fit Army aircraft, without several hours of modifications. It didn't go into the technical reason, bomb shackle spacing or what. And this would have been late in the war. The Army and Navy in most countries didn't set very good examples for co-operation, but the Japanese set new standards in interservice rivalry.

Well you can see there what I was talking about in my introduction, Japan was in war against the allies and against their own technological mistakes too.

Type 89 (Army)

This basic weapon was a desig largely based on the Vickers class "E" machinegun. Big numbers of class E were bought in late 1920s-early 1930s along with french and british aircraft so the Army adquired the license and modified the action slightly to acomodate his new calibre 7,7x58SR in 1935. The Type 89 was a simple and strong weapon almost entirely used in pair above the engine with synchronization. As it was the rule in those years the aircraft machinegun employed a high pressure ammunition not recomended to use in land weapons. It was used on Nakajima Ki-27, Ki-43, Ki-44, Mitsubishi Ki-60, Ki-61, etc.

Caliber: 7.7x58 semi rimmed (Arisaka)

Weight: 12.1 kilos

Rate of fire: 750 to 800 rpm (synchro)

Action: short recoil, toggle operated bolt, muzzle booster. Fed by disintegrable metallic belt, air cooled.

Muzzle velocity: sources varied a lot, between 760 to 830 meters per second.

 

[muscogeemike]

You only have to go back as far as 1983 and the invasion of Grenada. US Army on the Ground, US AF in the air, and the US Navy often couldn't communicate - our radios didn't have that capability! I often think that inter service rivalries have been responsible for more dead service men then the enemy.

 

[CharlesBronson]

That sounds bad, but I think this japanese issue is worst because is more like this: you are in battle and run out of ammo in your M16 and you cannot ask to the USMC personnel next to you some cartrigdes because they use other completely different than the 5.56mm....not nice, that surely would cause dead soldiers as well.

TE-1 machinegun (Army)

A 7.7mm arisaka caliber, semi-flexible gun for defensive purposes (and I wrote semi because the angle of movement was limited) is no other than a Type 89 in a sting mountig for rear defense. This gun was fed by the left side only. Because is a free mounting without the lag of being sinchronised the rate of fire is a bit higher, from 900 to 920 rounds per minute. other characteristics. weights and dimentions are pretty similar to the standar fixed Type 89. The gun apparently was used only in Mitsibishi Ki-21 "sally" and Ki-30.

Rear end Te-1 in Ki-21, photo with and without canvas cover.

 

[R Leonard]

Tony Williams ponders some these issues
BOOKS BY ANTHONY G WILLIAMS

 

[CharlesBronson]

I am familiar with Tony books and website.

Type 89 Special (Army)

Denomination of this weapon is really deceiving because is not a machinegun derivated from the standard 89 model but a completely new one. It is formed by two type 11 infantry machineguns wich lay flat, one in his right side and other in his leff. Ammunition fed was acomplished by 2 unusually shaped top magazine, inside the magazine there is 1 non-disintegrable belt feeding each chamber. The action is gas operated with a Kawamura designed falling block breech. Apparently the only reason to create this weapon is to obtain a higher rate of fire in defensive emplacements, aniway the gun rate of fire is not that much and manipulation of the large and bulky magazines was ackward to say the list.

Caliber: 7,7x58SR

weight; 26 kilos

rate of fire : 750 per tube, 1500 rpm total

Overall lenght: 1090mm

Rear turret Ki-21

Top view, note the "quarter cheese" shape of magazines.

 

[CharlesBronson]

Type 92 machinegun (Navy)

Is no other than the Birgmingham Small Arms Lewis machinegun with small modification, the japanese purchased a large quantity of pattern 2nd Lewis from 1921 to 1931 and then obtained the licence. The guns were assembled in Yokosuka Naval Arsenal althought the manufacture was distributed between 15 subsidiaries. The gun retained his original .303 caliber and obviously was not interchangeable with arisaka ammunition. It had a gas operated action and was fed from drum magazines holding either 47 or 97 rounds. It was used in many bombers, torpedo and recce planes like Yokosuka H6K, H8K, Nakajima B5N, B6N, Mitsubishi G3M, G4M, Aichi D3A, etc. For all purposes the rate of fire (650-700) and caliber became obsolete even before WW2 started.

Type 92 in B5N

 

[CharlesBronson]

Machinegun type 98 (Army Navy)

Yet again a licenced gun, this was a Rheinmetall-Borsig MG 15 locally made. The caliber is the original german 7.92x57mm. Used in flexible mounting by the 2 air arms. The shape of the receiver is a bit more "square" than the german made MG. General finish of machining and milling were a bit more rough althought the type 98 ussually works fine. The Navy variant is easily recognizable due the aditional wooden handgrip .

Side emplacement Nakajima Ki-49.

captured navy type 98

The gun was recoil operated with an interrupted thread locking ring. Rate of fire 1000 rounds per minute, muzzle velocity (with 1942 japanese ammunition) 800 meter per second.

 

[Bramak17]

Any reference on the type 2 13mm(?) machine gun that navy deployed Geordie the end of the war? As far as the rivalry went that had to be specifically addressed several times in reguards to making a unified defense late in the war speaks volumes as to how deep and idiotic a practice it was. Is it correct the army had its own carrier?

 

[Shortround6]

As far as the gun goes see: The Pacific War Online Encyclopedia: Japanese 13mm Type 2 Machine Gun