Navy 30mm aircraft guns

[genkideskan]

The japanese navy used Oerlikon guns. The 30mm Type 2 model 1 gun was a blown up 20mmType 99 model 2 system using a copy of the german MK 108 ammunition. Like the 20mm it was belt feed and used to fight the B 29 over Japan. The reason for this developement was to simply bring more explosive into the target. For the strong US bombers a 30mm projectile becomes nessessary.
Oerlikon guns couldnt be synchronised so the gun couldnt be used to fire through the propeller. Some where used in the Raiden fighter. I still look for more pictures, but the gun is hard to ID. Only the thicker barrel indicates a Type 2. Here is the gun ,the ammo and a Raiden wing installation.The 30mm gun was installed beside a 20mm gun. May be someone has closer informations or some more fotos.

[genkideskan]

The Type 2 fired this 30 x 90 RB round using a 42 rd magazine or a beltfeed system. The gun weight was 51 kg and the length was about 2,00 meter. The projectile reached a velocity of 500m/sec and the rate of fire was about 380 rd/min. The gun was made at Dai Nippon Heiki Seisakusyo. Enclosed are some pages of the ammunition manual.

[Panzerknacker]

Nice info, here a image of the other navy 30 mm, the Type 5.

[genkideskan]

I just read in an US report, that the Type 2 was used in wing mounts in Mitsubishi Zero fighters. At “least” 3 where wing armed with these guns in Rabaul in July 1943. That is very early I think. The weight for the 30mm gun was up to double the weight of a 20mm Type 2 and about three times the muzzle energy of a 20mm gun. That might be a problem for the aircraft designers to manage the recoil and drag forces.

[Panzerknacker]

Early indeed, Here you got another source.

Two 7.7 mm Type 97 machine-guns in the upper fuselage decking and two wing-mounted 30 mm cannon (experimental installation on A6M3).

http://www.combinedfleet.com/ijna/a6m.htm

Personally I think the Zero s wing structure is too light to handle the bulk of this weapon, but so little has been told or wrote about the japanese guns that everything is possible.

[genkideskan]

Panzerknacker thats a nice find. Now I need to check a bunch of Zero fotos for a 30mm barrel :-).

[genkideskan]

Here is a comparision foto of the 20mm Type 99 model 1 and 2 and the 30mm Type 2 cannons.
Note that the 30mm barrel is fluted - may be a help to ID the Type 2 on fotos.

[genkideskan]

Heres the Foto

[Tony_Williams]

The 30mm Type 2 was never officially adopted; it was apparently a “private venture” within the IJN which was rejected by the leaders, so it was only fitted to a handful of aircraft for a brief period - but it seems it did get into combat!

The ammo was 30x92 and was not a copy of the MK 108’s 30x90; the case is a different shape, and the loading was very different, with a much lighter shell (264 g v. 330 g) fired at a much higher velocity (710 m/s v. 505 m/s).

The IJN’s “official” 30mm gun was the Type 5 which was entirely original, not being a copy of either the Oerlikon or of the Army’s favourite, the Browning. Only a few of those had time to get into service.

[genkideskan]

Ok lets say influenced by the MK 108 ammo.:mrgreen:

[genkideskan]

The Type 5 30mm gun is somewhat better documented. K. Huddle and T. Bradstreet examined a surviving gun in the USA and interviewed the inventor.
Ted send me a copy of the results 10 years ago.
Chief of the developement staff was Dr. Masaya Kawamura the designer of the after war Type 64 MG used by the JSDF. Dr. Kawamura developed a belt feed system for the 20mm Type 99 guns too. Even the US Bombing Survey singled it out as an original and efficient gun. The Type 5 developement was
started in 1942 as the 17 shi Navy requirement and adopted in June 1945.
Barrel and receiver recoil as an unit sliding on a topcover.
The gun weight was only 70 kg - in that class the german MK 103 weights 140 Kg. In a MOD Pattern room report Dr. Kawamura states that 3000 guns where made. The use in Raiden fighters is known - a wing mount with long outboard gun barrel fairings. The 30 x 123 ammo is belt feeded.

[genkideskan]

The gun examined by Bradstreet and Huddle has the serial number 1724 made by Toyokawa Naval Arsenal. The limited ammunition supply of the Type 2, a major reason for the navy to cease production, was solved with a belt feed system. No surviving belt links are known, but they might resemble the hook and eye type of the Type 99.
The Type 5 was planed as nose weapons of the Kyushu J7W1 Shinden fighter.
The foto shows dummys to give weight for the test flights.

The A7M2-3 Reppu Kai has thicker wings than the Zero and M2 Reppu and might be designed for in-wing T 5’s.
Upward installations are known from P1Y2-S Kyokko ( Frances) and C6N1-S Saiun (Myrt) aircrafts. Both of these have Y0D tail codes. The Myrt installation is a known field installation completed in June 1945 and flow in hugh altitude patrols by Hiroshi Yasuda and Taro Fukuda.

A Raiden with the gun fairings was transported to the USA - the foto still showes the fixed ruders.

.

[Panzerknacker]

Excellent !! Very good werk Lothar, you got five stars

[Tony_Williams]

I’ve just posted a new article on my website on collecting 30mm cannon cartridges, and this is a pic from it:

30x184B (MK 101/103), 30x90RB (Mk 108), 30x92RB (IJN Type 2), 30x114 (IJA Ho-155), 30x122 (IJN Type 5)

[genkideskan]

Yes I saw it in IAA forum. Very nice article Tony. What a coincident that we here discuss the japanese 30mm ammo.

[genkideskan]

Like mentioned befor, annother plane armed with the Type 5 gun was the P1Y2 Kyokko Frances. Armed with 20mm guns in the nightfighter role this aircraft was equipped with the 30mm gun too. Only minor modification was nessessary. Note the same tailcode as the Myrt. YOD.

This unit was attached to defence the Tokyo aerea.

.

[Panzerknacker]

Like mentioned befor, annother plane armed with the Type 5 gun was the P1Y2 Kyokko Frances

Interesting.

Do you now wich was the figure of manufacturing of that aircraft ( non 30 mm variant included) ?

[genkideskan]

Until October 1944 453 planes where build - I am not sure if they build some more in 1945.
A real firepower prototype has 10 20mm guns firing forward - :mrgreen:
That beats the devil out …

[Panzerknacker]

Thanks for the data