Author Topic: On the Type99 cannons, A6Ms, and N1Ks  (Read 1157 times)

Offline FDutchmn

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On the Type99 cannons, A6Ms, and N1Ks
« on: January 09, 2003, 05:46:17 AM »
For your interest...

This is a summary of a report I did for Air Warrior way back when... please correct me if I am wrong...

Sources:
"Fighter: Shidenkai" by Y. Ikari, 1975
"Reisen, A small history of the Japanese Naval Aviation" (Japanese book, I forget the details)
ISBN4-7698-0631-0  "Shiden, Shidenkai, and Type94 Float Plane" edited by Magazine Maru Editorial Department 1992
ISBN4-499-22608-2  "Aero Detail 7 Mitsubishi A6M Zero Fighter" by S. Nohara 1993
ISBN4-499-22711-9  Kawanishi N1K2-J "George" Shiden-Kai

On the Type 99 cannons:
The difference between the Type 99-1 cannon and the Type 99-2 cannon is the length of the barrel, Type 99-1 being lighter by 10kg.  Muzzle velocity differed by 150m/s which is 600m/s and 750m/s respectively.  Ballistics were that when the shells travel 500 meters, they drop 1.5 meters for the Type99-1 and for the Type 99-2, it was half of the Type 99-1.

The Type 99-1 Model III had drum type magazine with 60 rounds.  Type 99-2 Model III had drum type magazine with 100 rounds.  Type 99-2 Model IV had belt-fed system.


On the A6Ms:
A6M2 had the Type 99-1 Model III with 60 rounds each in favor of the 10kg difference in weight.  It says in the book "Reisen, A small history of the Japanese Naval Aviation", that from the fourth plane in production, they switched to a magazine with 100 shells.  Were they able to enlarge the drum type magazine without changing the gun itself... I donno...  The first plane of this type was in production from December 1939 and 64 were produced at the Mitsubishi plant.  This was the Model 11.

The wing folding type of the A6M2 (740 planes at the Mitsubishi plant) for the CVs were in production from 1940.  This was the Model 21, which made itself known in the Pacific War.

A6M3 Model 32 went into production July 1941.  A6M3 Model 22 went into production in autumn 1942.  In this model, the cannons changed to the Type99-2 Model III in favor of the ballistics, and the planes with these cannons were called the A6M3a.

The next version is the A6M5 Model 52 which went into production summer of 1943, 747 being produced at the Mitsubishi plant.  The table of the Zekes in the book lists no modification on the guns from the A6M3.  So, I think the cannons for the A6M5 was still the Type99-2 Model III with a 100 shell magazine.  

The belt type Type99-2 Model IV was first used on the A6M5a which was first built in autumn 1943, with an increase of shells to 125 per cannon.  391 planes of this type was produced in the Mitsubishi plant.


On the N1Ks:
The Shiden (N1K1-J) was fitted with two Type99-2 Model III with drum type magazine of 100 rounds each and two 7.7mm machine guns which was the case with the Kyofu (N1K1), the float plane where the Shiden originated from.  The N1K1-Ja had the two 7.7 mm machine guns replaced with two more of the Type99-2 Model III.  This modification happened after the first 300 N1K1-J were built.  It seems they had to build a casing attached to the wing to incorporate the extra gun on each wing, while the space for the 7.7mm still left as is.  So, with this modification N1K1-J became the N1K1-Ja.  The N1K1-Jb had the belt type Type99-2 Model IV.

The Shidenkai, N1K2-J, had four of the belt-fed Type99-2 Model IV from the beginning. (Post edit: I forgot to mention that the ammo load for the N1K2-J is 200 rounds for the inner guns and 250 rounds for the outer guns for a total of 900 rounds... This was in response to the question posted over at the Gameplay Feedback/issues forum. Did n1k2-j really carried 900 rds of cannons??? )



Well... that's it for now... :)
« Last Edit: January 09, 2003, 11:08:28 PM by FDutchmn »

Offline lord dolf vader

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #1 on: January 09, 2003, 03:10:03 PM »
always love reading this stuff thanks.

got a book here that shows

a6m5b had one 7.7 replaced by one 13.2mm what ever that means

and a6m5c with ( get this ) 3, 13.2mm and two 20 mm


the book dosent mention what guns the 13.2 mm are. I wonder if they were h.e. rounds also?  the japanese seemed to favor explosive rounds alot more than anyone else from what i have seen.  that is one large bundle of firepower on a zeke.

love to see it in ah.

Offline brady

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #2 on: January 09, 2003, 03:40:26 PM »
The shell the Type 99 fired was the same, that is to say the Prodjectile was the same the case was smaller on the Type 99MK I than on the II.

 The Japanese did favor HEI rounds over AP, typicaly the tracer was the AP round it being AP/tracer, so the chain would be somthing like 4 HEI and one AP, this is true for both armay and Navy planes.

 Bearing the above in mind it should be noted that the type 99 MK I should have a very simmilar effect on impact as the Type 99MK II does, although with the slopier and slower balastics the Type 99 MK I would and is harder to hit with.

 I had the distenct pleshure in actualy handeling both the Type 99 MK I and the Type 99 MK II at a local Museum, they were very well made and both easly handeled.
   
   I have a Technical Manual for Japanese explosive ordance TM-1985-5 compiled by the US Army during and after the war, it is very percise in it's descriptions of ammo for these weapons, unfortunatly it is in storage at present, other wise I could put up some scans of the ammo types for the guns.

 In my experance in the A6M5 it is very capable of killing my personal best is 17 kills with cannon, acording to some chart I saw the Type 99 hits 99% as had as the Hispano in AH.

 Hear is an old scan I took out of the forementioned manual showing the HEI round:

 http://groups.msn.com/Photosforposting/type99iiiammo.msnw

       
« Last Edit: January 09, 2003, 03:52:23 PM by brady »

Offline FDutchmn

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #3 on: January 13, 2003, 05:44:57 AM »
Quote
Originally posted by FDutchmn
"Reisen, A small history of the Japanese Naval Aviation" (Japanese book, I forget the details)


I borrowed this book again... because I thought this book is of value... here are the details:

ISBN4-257-79028-8 "Reisen, Nihon Kaigun Koku Shoshi" [Zero Fighter, a look into a part of the Japanese Naval Aviation History] (this is more an appropriate translation)

this is written by  Mr. Jiro Horikoshi, chief designer of Type 7 Carrier-bourne Fighter, Type 9 Single seat Fighter, Type 12 carrier-bourne fighter, Type 14 Interceptor (? - Kyokuchi sentouki), Type 17 Carrier-bourne Fighter, at Mitsubishi Aviation  and by Mr. Masatake Okumiya, former equivalent of Commander of the IJN.

Quote
Originally posted by lord dolf vader
a6m5b had one 7.7 replaced by one 13.2mm what ever that means


what this means is that there were two 7.7mm machine guns in the nose of the Zeke.  One of these were replaced with one 13mm machine gun... the book is 600 pages long... I haven't been able to find the type of machine gun yet.  But I believe AH lists is correctly.  (on the help page the 7.7mm machine gun is missing from the A6M5b though.  In the hanger it's there.)


Quote
Originally posted by lord dolf vader
and a6m5c with ( get this ) 3, 13.2mm and two 20 mm


On the A6M5c, two more 13mm machine guns were placed in the wings out side the landing gears.  I guess that the weight limitations dictated that the 7.7mm machine gun be removed.  In addition, small rocket bombs (two on each side, total of four) were placed under the wings.

But... at the Mitsubishi plant, only 97 of these were built... on the other hand 470 of the A6M5b were built at Mitsubishi plant.  I am not sure about the Nakajima plants...

well, this is just for your interest too

Offline Dr Zhivago

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #4 on: January 13, 2003, 10:16:47 AM »
Quote
Originally posted by FDutchmn
what this means is that there were two 7.7mm machine guns in the nose of the Zeke.  One of these were replaced with one 13mm machine gun... the book is 600 pages long... I haven't been able to find the type of machine gun yet.  But I believe AH lists is correctly.  (on the help page the 7.7mm machine gun is missing from the A6M5b though.  In the hanger it's there.


Its Type 3 13.2mm machine gun ,weight 27.7kg ,muzzle velocity  790m/s and rate of fire 750-800...

(A6M5b) One 7.7 mm Type 97 machine-gun and one 13.2 mm Type 3 machine-gun in the upper fuselage decking, and two wing-mounted 20 mm Type 99 cannon

(A6M5c, A6M6c and A6M7) One 13.2 mm Type 3 machine-gun in the upper fuselage decking, two wing-mounted 13.2 mm Type 3 machine-guns and two wing-mounted 20 mm Type 99 cannon

Offline brady

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #5 on: January 13, 2003, 04:15:44 PM »
13.2 mm Type 3 machine-gun , Just think 50cal Browning, prety much the same thing.

Offline lord dolf vader

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #6 on: January 13, 2003, 04:52:39 PM »
pretty much in velocity also. looks like that would be one fun zeke to fly.

Offline Tony Williams

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #7 on: January 14, 2003, 03:11:15 PM »
Quote
Originally posted by brady
13.2 mm Type 3 machine-gun , Just think 50cal Browning, prety much the same thing.


Almost EXACTLY the same thing...it was a straight copy of the Browning, the only significant difference being that it was chambered for the 13.2x99 Hotchkiss cartridge already in use in the IJN's Type 93 AA gun instead of the US Browning's 12.7x99 - and the only real difference between them was the bullet diameter.

You will find comparative pictures of the ammo (and for the 20mm guns) in the ammunition photo guide on my website. The history of the Type 99s is also covered in the article "of Oerlikons and other things" on my site.

The 100-round drums for the 20mm were interchangeable with the 60 round drums, although they obviously needed more space. The drums for the 99-1 and 99-2 were different, as the 99-1's 20x72RB ammo was shorter than the 99-2's 20x101RB.

Tony Williams: Military gun and ammunition website and Discussion forum

Offline brady

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #8 on: January 14, 2003, 03:20:32 PM »
Hiya Tony:

    Did you get my E-mail about the HS 404?, or see the post I put up on your web sight?

 Hiya Tony, Brady from the AH BBS, I also Play WW2 online.
I am having the same problem with the recent adation of the D.520 to WW2 online it is geting 10 to 12 kills with one ammo load aganst all types of German armor fielded in France in 1940, from all angles, this realy is blowing my preception of reality out of the watter I was hoping if I came to gods house he could help to deleaver me from this delemia by casting my fears aside and sheding some light on this.:)

To put a stiutation to you:

A D.520 strafes a colom of P IVD's from the rear at 30 degreas and 300 yards what happens?(figure 10 to 15mm top armor plate, some Early war German aromr had top plaes as thik as 17mm, but the PIVD had 10 and 12 mm plate)

Note they are using this as a referance:

http://www.lanparty.com/lmo/ww2/test/hs20mmtest.pdf

Offline HoHun

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #9 on: January 14, 2003, 08:40:50 PM »
Hi Tony,

>The 100-round drums for the 20mm were interchangeable with the 60 round drums, although they obviously needed more space.

This is not as obvious as it may appear since the German MG-FF 90-round drum fit into the same space as the 60-round drum :-)

Regards,

Henning (HoHun)

Offline Tony Williams

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On the Type99 cannons, A6Ms, and N1Ks
« Reply #10 on: January 15, 2003, 12:12:43 AM »
Quote
Originally posted by HoHun
Hi Tony,

>The 100-round drums for the 20mm were interchangeable with the 60 round drums, although they obviously needed more space.

This is not as obvious as it may appear since the German MG-FF 90-round drum fit into the same space as the 60-round drum :-)

Regards,

Henning (HoHun)


Fair point, although I think that was a later development.

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