Nakajima Ki-43 Hayabusa ("Oscar")

[Bino]

Your classification claim and your insistence that the mixed 7/12mm load out is the sole and most prevalent is directly contradicted by:
A Research Study by Richard L. Dunn (c) 2002, 2004: Nakajima Type 1 Model 1 Army Fighter (Ki 43-I) Armament -- A Reassessment (part 1) http://www.warbirdforum.com/rdunn43.htm
as well as the less reliable Wikipedia article on the Ki-43 http://en.wikipedia.org/wiki/Nakajima_Ki-43
...

That excellent paper you cite by R. L. Dunn concludes with this:

"Based on the evidence marshaled in this study (which admittedly does not take into account all units equipped with this aircraft much less present direct evidence as to each aircraft) the main operational version of the Ki 43-I was equipped with one 7.7mm machine gun and one 12.7mm machine cannon. This version was in operation in Indo-China and Malaya early in the War; in Burma in late 1942; and, in the Southeast Area from late 1942 to mid-1943. A captured aircraft in China confirms the version with two 12.7mm machine cannon but reinforces the impression that this configuration was limited to a small number of early production aircraft. While versions with two 7.7mm machine guns existed, they were likely retrofitted aircraft relegated to non-combat roles."

So, while some examples of the Ki-43 appear to have used either the twin-7.7mm or the twin-12.7mm set up, the mixed 7.7mm/12.7mm seems to have been the most common armament used in service.

I was startled to read that the early 12.7mm "machine cannon" sometimes had ammo explode in the barrel, and that one Fighter Regiment actually lost aircraft because of engine damage caused by this!   

[Krusty]

I made a post a while back about this topic and also was referring to Dunn here as well. Although, I was going more off of this:

http://www.j-aircraft.com/research/rdunn/nakajima_ki43arm.htm

I'm not sure why you brought this article up seadog, as it only helps what I've said.   


EDIT: Just to nail the coffin shut:

The “received” version of the history of Ki 43-I as discussed in the Introduction is almost certainly wrong. If the Ki 43-I was originally placed in production with two 7.7mm machine guns, these early aircraft either did not go into action or were modified with one 12.7mm machine cannon prior to doing so. In early combat operations the 59th and 64th FR almost certainly operated aircraft with the mixed armament to the exclusion of the other versions. Not only does Dr. Izawa’s article state that this was the armament of the 64th FR Ki 43’s but ammunition expenditure data for the 59th FR confirms it for that unit. Three Japanese Monographs in addition to the one providing ammunition expenditure data provide general support for the mixed armament being used in early operations.

     Crash intelligence regarding aircraft of the 50th and 64th FR indicates this armament was still in use by these units in Burma in October 1942.

     The 1st and 11th FR took the Ki 43-I to the Southeast Area in late 1942 and early 1943. The evidence indicates that their aircraft (which represented a significant portion of the Ki 43-I fleet) were fitted with the mixed armament.

     Limited examples of other versions of the Ki 43-I were found. However, even if these aircraft were produced with two 7.7mm or two 12.7mm guns and not modified in the field, their serial numbers are out of sequence with the commonly accepted history of this aircraft. The production sequence: A(2x7.7) –B(1x7.7 and 1x12.7) – C(2x12.7) clearly did not occur.

     Based on the evidence marshaled in this study (which admittedly does not take into account all units equipped with this aircraft much less present direct evidence as to each aircraft) the main operational version of the Ki 43-I was equipped with one 7.7mm machine gun and one 12.7mm machine cannon. This version was in operation in Indo-China and Malaya early in the War; in Burma in October 1942; and, in the Southeast Area from late 1942 to mid-1943. A captured aircraft in China confirms the version with two 12.7mm machine cannon. While versions with two 7.7mm machine guns existed, they were likely retro-fitted aircraft relegated to non-combat roles.

[Krusty]

And again, remember this is only the Ki-43-I model. Production stopped in Feb 1943 and moved to the Ki-43-II. The -I kept serving in 1943 as it was replaced. The -II began service in that summer.

Differences from the I to the II:

-I apparently had no reflector sight
-II added a reflector sight

-I had a 2-blade prop with only 2 pitches (not fixed, not constant speed)
-II had a standard constant speed 3-blade prop.

-I had no protection and pilots complained about the effect of superficial damage
-II added basic pilot armor, some fuel tank protection, etc

-I performance was much lower
-II had a more powerful engine, ejector stubs for more thrust, shorter wings for more speed down low.

(It will be interesting to see if HTC can model a 2-pitch screw like that. Maybe add part of the engine-over-rev from the WW1 arena onto the Ki-43-I, where you overrev and damage the engine?)

There are more, but from a top-down I think those would be the main characteristics that separate them.

There is an interesting comment from the warbirdforum.com on Joe Baugher's Ki-43 page. It says:

...when the 64th Sentai was reequipped with Ki-43-II models in April 1942, both nose guns were large-caliber. However, the rate of fire was so slow that many or most pilots had one gun taken out and replaced with a faster-firing 7.7mm. These were the models that fought the AVG on 28 April 1942 near Lashio, Burma.

So while the 12.7mm may have been more common on the -II (I can't say for sure) it appears the same problems were still in place that drove the -I to use the mixed armaments.
(Link: http://www.warbirdforum.com/hayabus2.htm down towards the comments area)

EDIT: Also regarding the -III (just as a side note) these did not begin production until December 1944. The war was nearly over. They were used in homeland defense often in the suicide role. They had more powerful engines but most of them still had the same 12.7mm armament. Some are reported to have had 20mm installed, but how many and where and when, is unclear. There's a bit of a debate from what I gather as to whether that's a prototype or a field test rather than a production run.

[RTHolmes]

Your classification claim and your insistence that the mixed 7/12mm load out is the sole and most prevalent is directly contradicted by:

... the mixed armament version ... was introduced very early in the production run (prior to the outbreak of the Pacific War) [and] was undoubtedly the major version of this aircraft to see action

that doesnt contradict what Krusty wrote, it backs it up.

if you're going to wade in like that, perhaps you should get your facts straight first. losing the attitude would also make it more likely that people will listen to you too ...  



edit: btw how much HE was in those .50s and were all rounds loaded exploding? as cannon rounds go, they're not very big ...

[Krusty]

No, not very much. you find the same thing in the Italian 12.7mm and in the German MG131. The content was explosive, but overall not nearly as much as on a 20mm. It's also likely they had mixed beltings (as both the IT and GE guns did) where not all rounds are HE, but only 1 or 2 out of every 5 or so were.

In Aces High we have averaged round damage, so I imagine it would be exactly the same damage as the nose guns on the Ki84 and the wing guns on the Ki61, but maybe with a much slower rate of fire. Some sources suggest the 900rpm dropped to 400rpm when synchronized. Hence why pilots wanted that 7mm.

[RTHolmes]

I flew the 84 a bit for the first time last tour and noticed the .50s seemed to be pretty hard hitting, I assumed it was because they were cowl-mounted so no convergence issues. learn something every day

[Krusty]

They're respectable, to be sure. I'm not sure the gun is the exact same (I haven't checked) but round for round, I expect the damage to be that same level. Weaker than a .50cal US gun. ROF should be a lot lower.

[Slade]

This version please:
Ki-43-IIIb (Mark 3b) - Variant armed with 20 mm cannons.


>> Total production amounted to 5,919 aircraft.

>>  In spite of its drawbacks, the Ki-43 shot down more Allied aircraft than any other Japanese fighter and almost all the JAAF'S aces achieved most of their kills in it.


Good enough for me.  +1

[Wmaker]

This version please:
Ki-43-IIIb (Mark 3b) - Variant armed with 20 mm cannons.

Only two prototypes were built.

[Volron]

+1 for the Ki-43.   (Toss in the He-111 H-11 while we're at it. )

[Raphael]

yes on ki43m and volron knows what he is talking about.

[Charge]

The reason for barrel explosions could also have been caused by the usage of "raw" explosive in HE ammunition. While Germans used e.g. clay to stabilize their explosives the Japanese were not too concerned by this and used them "raw" for most effect. It could also be caused by defective fusing in ammo since there were reports that HS 404 had this problem too that some rounds exploded right after leaving the barrel and some even in the barrel.

-C+

[HighTone]

I like this wish to much to see it fall to the second page so quickly.

The Ki-43II would be a great challenge for the LWA and would draw the same kinds of pilots as other planes of its class. I cant wait for the first FSO that I get to fly a Oscar 

[Krusty]

As far as filling holes in the planeset, the Ki-43-I remained in frontline service well through 1943. The Ki-43-II was a late war bird.

To really fill holes (like, say the Rangoon scenario running now) we would need the -I more than the -II. I can't imagine why we'd get one without the other, but just in case I thought I'd mention which is more important

[Karnak]

Ki-43-II would be a mid-war aircraft as it entered service in Dec. of 1942.  Don't know where you're getting late war for it.