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AIRCRAFT WEAPONS
Topics:
Zero Cannon
20MM Cannon (for Models)
Aerial Firecrackers
Aircraft Weapons (New)
Type 89 Machine Gun (New)
Posted By: Mark Smith <MarkA6M2@aol.com>
Date: Sunday, 15 July 2001, at 7:05 p.m.
Hi Greg,
In Chicago, I finally saw the Iida Zero you finished which I had heard so much about. A beautiful piece of research and an exceptional model. Where did you find out about the cannon bay skylights, and how common were they? Anyway, great job.
Mark Smith
Posted By: Greg Springer <gspring@ix.netcom.com>
Date: Monday, 16 July 2001, at 5:38 p.m.
Hi Mark,
Thank you very much! Nice to hear from you. It was Ryan Toews who discovered the skylights on some of the Blayd artifacts. Later I discovered they were labeled in the old Maru Mechanic as well but 25 years ago I couldn't translate simple kanji phrases. I feel that they were present on all the early model 21s. I am not sure about 32s and 22s. It looks as if a D-shaped hatch was substituted which still had a small skylight in it but at some point the skylight may have been deleted. That hatch may have been present on the model 21s after they were given the 100 round ammo drums. Ryan may be able to shed more light on this. Ouch!
Sorry!
Cheers!
Greg
Posted By: Ryan Toews <ritoews@mb.sympatico.ca>
Date: Friday, 20 July 2001, at 12:32 p.m.
Hello Mark, Greg,
It would appear that the clear skylight was replaced with a U or D shaped access panel in conjunction with the larger 100 round magazine. My conjecture is that something about the new magazine made it necessary to be able to get at it from the top in order to mount it in place. I do not believe that the clear skylight was still present in the new access panel. If you look at the photos of the Zero 32s captured at Buna no clear panel is evident, and these A6M3s are all very early production aircraft with serial numbers in the 3020s and 3030s.
The later model Nakajima A6M2s were also fitted with the 100 round magazine and they too exhibit the new access panel. An example of this can be seen on the converted two seat Zero pictured on the top of page 8 of FAOW 55. These same pictures also show the small oval release latch situated a few inches further back on the wing. I have a photo from Jim Long that indicates that this latch had a small black dot painted on it to indicate where it should be pressed to release the catch.
The issue of the changes in the magazine capacity also raises two additional points. First is the question of when the Nakajima built A6M2s switched to the new equipment. An increase in the empty weight listed on four A6M2 manufacturer plates may indicate that the 100 round drum was in use by June 1943.
Mitsubishi s/n 4593 (Feb 42) 1715 kg
Nakajima s/n 6743 (Mar 43) 1716 kg
Nakajima s/n 7835 (Mar 43) 1722 kg
Nakajima s/n 11399 (June 43) 1735 kg
Two pieces of evidence can in turn be cited to establish a date at which the small magazine drum was still in use. The wing of A6M2 s/n 5459 (made December 1942) in the Blayd collection does not have provision for the larger bulged access panel needed to accommodate the larger drum. As well, the Nakajima built A6M2 in factory applied dark green top and gray bottom camouflage (introduced in the late spring of 1943) on page 69 of FAOW 55 retains the smaller access panel associated with the 60 round drum.
If this line of reasoning is right, the larger capacity drum was adopted after the introduction of the two-tone camouflage scheme but before June 1943.
The second problem that shows up is try to establish the details of when the cannon shell ejection chutes began to be equipped with a movable cover. Such covers, hinged on the right side on both the right and left wings can be seen on the aforementioned two seat Nakajima built A6M2 pictured on page 22 (photos 82 and 83) of Aero Detail 7, on the underside view on page 55 of FAOW 56 of a Nakajima manufactured A6M5 captured at Saipan Zeros (now in the Planes of Fame Air Museum) and on the Mitsubishi built A6M5 in the
NASM.
Additional dust protection was also found on the Saipan Nakajima built A6M5, tail code 8-07, that had "An air seal ... provided to close the opening in the leading edge of the wing around the barrel of the cannon. This seal consist[ed] of a fabric backed imitation leather jacket fitted to the wing contour and fastened to the leading edge of the wing by a metal retaining strip secured with flush screws and anchor nuts. A drawstring is used to seal the jacket tightly round the barrel of the cannon."
The advent of the A6M5a fitted with the Type 99 Mark 2 Model 4 cannon saw the use of internal dust prevention doors. But because they were inside the chutes they are not visible regardless of whether they are open or closed.
It may be that all this was a field modification as no mention of it can be found in the Zero Handling Manual. But if one is allowed to really go out on a limb an argument can be constructed that says that this was a factory modification. As far as I can see, none of the three planes with the shell ejection chute covers listed above have the rectangular flaps used to allow air circulation to cool the gas tanks on the underside of their wings. Yet the NASM Zero still retains the two red handles (found on the right cockpit floor, see Mikesh, Japanese Aircraft Interiors, page 136, upper right photo) that controlled the opening and closing of these flaps. Is it possible that the wing gasoline tank cooling flaps were replaced by dust protection flaps that used the same manual control linkage?
Some time back Rick Dunn also pointed out that the "Handling Manual for Firing Equipment" (OP 16 FE translation no. 244 AS811 1945) gives the details. From December 1942 to June 1943 one half the Mark II Zeroes [the A6M3] were to be equipped with Type 99 Mark II cannon. (Picks up the tail end of Model 32 production). After July all aircraft got the new weapons. We know some model 32's actually did get these guns because, for example, A6M3 # 3305 which was recovered nearly intact from the water near Kolombangara was armed with these weapons." It may be that some very late A6M2s also were equipped with the long barrel Type 99 Mark II cannon as seen in the photo of the captured A6M2 with the ATAIU-SEA tail code BI-12.
At this point I realize I have strayed some distance from the original question about the clear skylights found in the A6M2 wing gunbays. Nevertheless this was a good opportunity to summarize some of the details of what I have found out (thank you Jim Long) about the wing cannons on "mid production" Zeros.
Ryan
Posted By: richard dunn <rdunn@rhsmith.umd.edu>
Date: Sunday, 22 July 2001, at 12:07 p.m.
Ryan
Glad if something I shared earlier has proved helpful. Here is a little additional info in line with your message (albeit also slightly off topic).
The late January 1943 delivery plan for February 1943 had 90 Zero 21's to be delivered. No indication any had Mark II cannon. Sixty Zero 22's were to be delivered. Of these thirty were to have Mark II cannon.
Rick
For March 1943 95 Zero 21's to be delivered. No indication of Mark II cannon. Sixty-one Zero 22's to be delivered of which thirty were equipped with Mark II cannon.
The total actual production figures are very close to these projected numbers (actually exceeded them slightly).
From a somewhat garbled intercept, I have inferred that the Air Arsenal at Soerabaja supplied 202 Ku with reconditioned Zero 21's with Mark II cannon in mid-1943. Cannot tell you anything about the specific configuration.
Posted By: Greg Springer <gspring@ix.netcom.com>
Date: Friday, 20 July 2001, at 3:37 p.m.
Hi Ryan,
Thanks for the information! My guess is that the hatch replaced the skylight because the increased weight of the 100 round drum required a second armorer on top of the wing to reach through to help lift and steady it while it was being latched to the receiver. This makes me curious as to how that attachment was made. I can examine a Type 99 No.2 cannon but I don't know if it was drum-fed or belt-fed.
Cheers!
Greg
Posted By: Tony Williams <autogun@globalnet.co.uk>
Date: Sunday, 22 July 2001, at 10:15 a.m.
I don't think that the Mod 3 guns with the 100-round drum were wing-mounted; AFAIK they featured in fuselage installations (although Ted Bradstreet will be able to confirm). The Mod 4 (of both Type 99-1 and 99-2) was belt-fed.
Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website:
http://www.users.globalnet.co.uk/~autogun/
Posted By: Ryan Toews <ritoews@mb.sympatico.ca>
Date: Monday, 23 July 2001, at 2:09 p.m.
Hello Rick and Tony,
Rick, thanks for the additional info. It would appear then that the long barreled 20mm on an A6M2 was only a field mod. It probably is purely coincidental but it is also interesting that 202 Ku, operating in an area that was liberated by Australian troops, was issued with rearmed 21s and it was a 21 thus equipped that was tested by the Brits at the end of the war.
Tony, it may be that some confusion exists on my part on the designation of the 20mm cannons. According the Mikesh I understand that the Type 99 Machine Gun (the Navy called everything up to and including 20mm an MG) Mk.1 Model 3 was used in the Zero and had a 60 round drum magazine which was then upgraded to a 100 round drum. The Type 99 MG Mk. 2 Model 3 used a 100 round drum magazine and had a longer barrel. The Type 99 MG Mk. 2 Model 4 had a redesigned receiver and used belt fed ammo. Until I went back and looked this up I must admit I had not realized that there was not a any change in designation in the first change from a 60 to 100 round drum. I suspect therefore that the reason for the D shaped access panel was only due to the increase in weight of the larger magazine and the "latch" system remained the same.
Ryan
Posted By: Tony Williams <autogun@globalnet.co.uk>
Date: Tuesday, 24 July 2001, at 1:15 a.m.
Well, Ted Bradstreet is the expert on all this but I do know that the range of different sub-variants of the Type 99s, for both fixed and flexible use, is overwhelming.
The basic distinction is between the Type 99-1 (Oerlikon FF) which fired a 20x72mm cartridge, and the Type 99-2 (Oerlikon FFL) which was not only longer - it fired a much more powerful 20x101mm cartridge, raising the muzzle velocity from 600 to 750 m/sec (there is an outline history of the various Oerlikon developments and derivatives on my website, if you're interested).
Each of these was first available with a 60 round drum, and each was also available later with a 100 round drum (the Model 3 in each case) and later still with belt feed (Model 4 in each case).
Exactly which weapons were fitted to which aircraft is something I'm a bit hazy about, I must admit, and you could well be right that some of the wing guns carried 100 round drums, but I have always associated these with fuselage-mounted guns such as the upward-firing ones in night fighters.
Tony Williams
Author: "Rapid Fire: The development of automatic cannon, heavy machine guns and their ammunition for armies, navies and air forces"
Details on my military gun and ammunition website:
http://www.users.globalnet.co.uk/~autogun/index.htm
Posted By: Ted Bradstreet <tbstreet@mint.net>
Date: Wednesday, 25 July 2001, at 3:38 p.m.
AFAIK, the 100-rd drum was used in all applications once available, including those still using earlier gun models (2-gata, etc.).
Posted By: richard dunn <rdunn@rhsmith.umd.edu>
Date: Tuesday, 24 July 2001, at 7:04 a.m.
Tony, Ryan et al
The details on the changes (including) the 100 round drum are laid out in the Handling Manual cited in one of Ryan's messages.
Rick
Posted By: steve allen <pee_weeuk@yahoo.com>
Date: Sunday, 29 April 2001, at 10:18 a.m.
ok, heres a difficult one. anyone know of a source for METAL eg brass 20mm cannon barrels in 1/48 scale I keep breaking the damn plastic ones off and they are getting a bit short......
Posted By: John Acosta <xmdjna@cs.com>
Date: Tuesday, 1 May 2001, at 1:28 a.m.
Hi Steve;
Good and bad news. Fine Molds made some really fantastic IJN 20mm cannon barrels from brass; they have the proper taper to them and flare out at the end. I used them on the last model I built about a year ago, which was Hasagawa's Raiden.
A friend of mine happened to have a set which he said he was not going to use.
Perhaps someone has some way to talk to the Gentlemen who run Fine Molds and ask them to please make these barrels again. These barrels are so very very nice and if I had about 20 more sets I would have enough for the Georges, Zeros, Gekkos and Raidens I plan to build in the future! They were offered as Fine Detail Accessories set # AC-1 for 1300 Yen.
Regards,
John Acosta
Posted By: Bert O. <n1k2j@aol.com>
Date: Sunday, 29 April 2001, at 10:47 p.m.
Try:
Hobby Hanger
PO Box 472
New Carlisle, IN 46552
They have a large assortment of diff. diameter brass tubing .004" ID to .040" ID. The one you want for 1/48 20mm cannon is BT030 .016" diameter. A 6" length is 3.99. The also have miniture springs.
I dont know if they are still around since I havent ordered in 2 years.
I dont know the source for this one but I remember seeing stainless steel tubing of diff diameters at a well stocked hobby store in Mesa AZ. I go there whenever I am on business in Phoenix. The supplier is out there somewhere but I dont recall the source. Check FSM, the model shop is listed there. Perhaps you can order it from them or get the source.
Posted By: Garth <goconnell@dingoblue.net.au>
Date: Sunday, 27 May 2001, at 7:53 p.m.
I am currently reading an absolutely fascinating and well-researched book and it mentions a very interesting defensive weapon being used by a 70 DCS Dinah over Western Australia during 1944. Could somebody please give me a better description/images of this weapon and its success rate? Thankyou kindly. :)
"A detachment of three Spitfires from 54 (RAF) Squadron, usually based at Livingstone in the Northern Territory, were stationed at Truscott, a remote base in Australia's far north western corner on 20 July 1944.
The RAAF radar station at Cape Leveque had warned of a possible hostile aircraft approaching and F/L D.M Gossland and F/L F. Meakin with F/Sgt A.E. Knapp were Airborne at 0850 hours. A Dinah was sighted at 27,000 feet and as the Spitfires approached from astern it was seen to release clusters of aerial firecrackers, which burst below and behind the British pilots.
F/L Gossland made his attack from the 7 o’clock position and his burst was seen to strike the port side of the fuselage, wing and both engines. The Dinah went into a steep dive. F/L Meakin fired a burst and the starboard wing broke away and the Dinah burst into flames and crashed into the sea, five miles north of Truscott strip.
The Japanese crew aboard this aircraft had been Lieutenant Kiyoshi Iizuka (pilot) and Lieutenant Hisao Ito (Observer). Another Dinah operating at the same time, off Broome and Derby, returned safely to Koepang, in Timor".
SOURCE: "The Hidden Chapters. Untold Stories of Australians at War in the Pacific". By Robert Piper, published by Pagemasters Press, Carlton Vic. (1995). ISBN 1 875575 22 7
Page 37/38
Posted By: Tony Williams <autogun@globalnet.co.uk>
Date: Monday, 28 May 2001, at 1:00 a.m.
Yes, these existed all right. Speaking entirely from memory, there was a 10-round launcher that fired spherical time-fuzed grenades, timed to explode about 100m behind the aircraft to put off attacking fighters. Somewhere I have a data sheet on the ammo, buried no doubt among the mountains of paper stacked around my room.....
Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website:
http://www.users.globalnet.co.uk/~autogun/
Posted By: Tony Williams <autogun@globalnet.co.uk>
Date: Thursday, 4 October 2001, at 1:56 a.m.
OK, I've done a bit of digging and this is some of the
information you're after:
The Army planes (Ki-44, Ki-61, Ki-84) all used the Army's
two standard guns in the calibres you asked about; the 12.7mm Ho-103 and 20mm
Ho-5. The only exception was a few (under 400) Ki-61, which were fitted with
German-supplied Mauser MG 151/20. Both the Ho-103 and Ho-5 were variations of
the US Browning design.
The Ho-103 used a smaller cartridge than the Browning
(12.7x81 instead of 12.7x99) and fired AP (35.4g) or HE (33g) projectiles at
around 760 m/sec. The gun fired at 900 rpm (unsynchronized; it was seriously
slowed down by synchronization).
The Ho-5 used a 20x94 round and fired either a 79g HEI
shell at 730 m/sec or a 119g API at 700 m/sec. Rate of fire was 850 rpm.
The MG 151/20 used a 20x82 round and fired 115g API or
HE/T at 710 m/sec or 92g M-Geschoss at 800 m/sec. Rate of fire was around 700
rpm.
The two Navy planes (J2M3 and N1K1-J) used the standard
Navy Type 99 20mm cannon, which were copies of the Oerlikon FF series. The
N1K1-J used the Type 99-2, which used a 20x101 cartridge (128g at 750 m/sec)
while the J2M3, at least initially, used a mixture of the Type 99-2 and the
earlier Type 99-1, which used a smaller cartridge (20x72) and fired the same
shells at only 600 m/sec (the 3a had four 99-2 cannon). Rate of fire of both
guns was only around 500 rpm.
The early versions of the Type 99 cannon used a 60 round
drum. This was later replaced by a 100-round drum, and later still with belt
feed, which pushed up the capacity to around 125 rounds. I don't have firm
information about the Army planes but all of the guns were belt-fed, and
capacities of around 125 rounds for the 20mm and 250 rounds for the 12.7mm
would have been typical.
I hope this helps!
Tony Williams
Re: US seat back armour vs Ho-5 or 99-2 cannon?
Posted By: Tony Williams <Tony.Williams@quarry.nildram.co.uk>
Date: Thursday, 11 July 2002, at 12:39
a.m.
I don't know about the armour protection, but the Type
99-2 should have been capable of penetrating up to 30mm armour at short range
(the Ho-5 perhaps 20-25mm).
However, these figures would be against armour in the
open. In practice, AP projectiles were much less effective against aircraft
because they had to plough through the structure before reaching the armour,
and this not only slowed them down but often made them tumble so they hit
sideways, drastically reducing effectiveness.
Tony Williams
Re: Japanese 20mm
Posted By: Tony Williams <Tony.Williams@quarry.nildram.co.uk>
Date: Saturday, 15 June 2002, at 12:36
p.m.
I have some examples of Japanese ammo in my collection
(20x94, 20x101RB, 20x125, 20x142) but they were not big on headstamps. My
examples have hardly anything except a single mark on some that apparently
meant, "tested". Elks' book includes just three examples of Navy
headstamps. They tended to stencil markings on the side of the cases instead.
Tony Williams
Posted By: Malcolm Laing <mlaing@door.net>
Date: Monday, 7 January 2002, at 10:00 a.m.
I am in desperate need for clear photos, drawings, etc.
of the flexible mount Type 89 machine gun. As used on a Ki-51.
Posted By: Tony Williams <a_g_williams@lineone.net>
Date: Tuesday, 8 January 2002, at 1:20 a.m.
I'll have a look to see what I have, but first you'd
better define which gun you mean:
"The IJA used the Vickers (which they called the 7.7
mm Type 89 Fixed) but this time chambered for the Army's own 7.7x58SR
ammunition. The Te-1 was a flexible version of this gun (it is sometimes
identified as the Type 89 Flexible but this designation was properly applied
to another gun, as we shall see). The IJA employed some of their own
developments; the 7.7 mm Type 89 flexible and Te-4, and 7.92 mm Type 100/Type
1 Flexible. The Type 89 Flexible was a gas-operated twin weapon based on the
Type 11 infantry machine gun and firing from a pair of complex quadrant
magazines at 700 rpm per barrel. It consisted of two separate, mirror-image
guns in a common cradle. The Te-4, generally marked "Type 89 (modified
single)", was a single Type 89 Flexible gun without a cradle and fed from
a 69-round pan at 730 rpm. It is often mis-identified as the "Type 89
Flexible", for fairly obvious reasons, but did not enter service until
1939 or 1940."
Tony Williams
Posted By: ted bradstreet <tbstreet@mint.net>
Date: Saturday, 12 January 2002, at 3:43 p.m.
Actually, the situation was even more complex than Tony
has it -- there were four (4) guns referred to by both Japanese and Allied
sources as "Type 89 flexible:" (1) a flexible version of the Vickers
(Te-1); (2) the original Type 89 twin, in service from 1929 to sometime in the
late thirties; (3) the Type 89 (special), the twin in service from 1933 to
1945; (4) and the Te-4, in service from some time prior to 1936 to 1945. (Had
to do that...) Am e-mailing you the three best images I have of the Te-4 --
you should get enough detail from the three to model one complete gun.
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