# HARDLYDANK's Ki-43 Variants Identification Guide



## Hardlydank (Jan 27, 2021)

This thread is to serve as a reference for Ki-43 variant identification. I have spent entirely too long studying photos, books, and technical drawings to figure out the variants. Hopefully this will also be of use to someone other than me.
Now, there are 3 main Ki-43 variants: Ki-43-I, Ki-43-II, and Ki-43-III. Within these are 8 subvariants. I won't be going through every single change through the sub-variants, only the ones that are relevant to identification.
*Ki-43-I (**Attachments** #1-2)*
The Ki-43-I is probably the easiest to identify. However, there is no way to distinguish the subvariants from each other. The only difference between them is the armament, so unless you can actually see the guns themselves in a photo there is no way to tell which subvariant it is. Attachments 1 and 2 show the identifiable features of the Ki-43-I
_*Ki-43-Ia (Ko)*: _2 0.30 cal machine guns
_*Ki-43-Ib (Otsu):* _1 0.30 cal machine gun and 1 0.50 cal machine gun
_*Ki-43-Ic (Hei):* _2 0.50 cal machine guns (used on all subsequent production variants)
*Ki-43-II (Attachments #3-8)*
The Ki-43-II was the biggest evolutionary step for the Ki-43. The main features introduced were a 3 bladed prop, reflector gunsight, and an upgraded engine housed under a more streamlined nose.
_*Ki-43-IIa Early (Ko):* _Attachment #3 shows the identifiable features of the Ki-43-IIa Early. Of note is the secondary oil cooler. I have outlined its shape on Attachment #3 in white. This is the only way to identify this subvariant if you can't see the oil cooler ring. The oil cooler in Attachment #5 is also outlined in white to show how the shape changed on the next subvariant, the Ki-43-IIa. The shape of it remained basically the same for the rest of the variants after the Ki-43-IIa Early. Attachment #4 shows a clearer view of the oil cooler ring. 
_*Ki*_*-43-IIa (Ko upgraded): *Having 2 separate oil coolers turned out to be overly complex and inefficient, so this subvariant deleted the oil cooler ring and had 1 large 'honeycomb' type oil cooler under the nose. Attachment#6 shows this. Attachments #3 and #5 can be compared to see the difference in size and shape of the undernose cooler.
*Ki-43-IIb (Otsu): *This subvariant has a smaller forward cowling opening and had its exhaust pipes angled backwards for slightly increased thrust. Attachment #7 shows the difference in the forward cowling opening and Attachment #8 shows the angled exhaust pipe.
_*Ki-43-IIc (Kai): *_This subvariant introduced ejector exhaust stacks which further increased thrust. The main problem with identifying this subvariant is telling it apart from the next subvariant. I'll say how to tell the difference on the next subvariant section.
*Ki-43-III (**Attachments** #9-11)*
_*Ki-43-IIIa (Ko): *_This is the last subvariant. I'll be showing how to tell the Ki-43-IIc and Ki-43-IIIa apart. There are 3 ways: the machine gun blast tubes, water-methanol filling port, and cowling opening shape. The Ki-43-III's blast tubes are set further back and have a vertical profile, while the Ki-43-II's blast tubes are more forward and are angled back at about 45 degrees. The water-methanol filling port is only present on the Ki-43-III, it's located behind the pilot's seat and is a cylindrical shape sticking up from the fuselage inside the canopy. The Ki-43-II's cowling opening has a downward curve around the carburetor intake, which on the Ki-43-III is straight. Attachment #9 shows 2 of the 3 identifying features compared on both subvariants. Attachments #10 and #11 both show the water-methanol filling port.

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## taly01 (Jan 29, 2021)

A nice summary  The bulges in front of the front cockpit sides on Ki-43-I are to clear the 12.7mm guns and ammo belt feed, i've been trying to find if early prototypes with 7.7mm did not have them as I think they were an afterthought in design (like Me109G-6 MG bulges!).

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## Crimea_River (Jan 29, 2021)

Thanks for doing this. If I ever get around to building one of these, this will be very helpful.

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## Hardlydank (Jan 29, 2021)

> A nice summary  The bulges in front of the front cockpit sides on Ki-43-I are to clear the 12.7mm guns and ammo belt feed, i've been trying to find if early prototypes with 7.7mm did not have them as I think they were an afterthought in design (like Me109G-6 MG bulges!).


This is all I could really find. Attachments #1-3 show prototype 4312 (12th prototype) after it crashed. The book I'm using says that prototype 4310 and 4313 had 2 0.50 cals but doesn't say what 4312 had. It kind of looks like there's a bulge on Attachment#1, but I can't tell for sure. Attachment#4 shows a wooden mockup of what the 1st 3 prototypes looked like. It's the only photo I've ever seen of one. You can make out what looks to be a hole for a machine gun on the upper cowling lip.


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## Vincenzo (Jan 29, 2021)

I was waiting our japanese members, but they not came
afaik the I ko, otsu, hei are post war western designation


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## tomo pauk (Jan 29, 2021)

Might be worth looking at: link

And this certainly: link

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## Hardlydank (Feb 12, 2021)

Update: corrected information on the difference between the Ki-43-IIc and Ki-43-IIIa. In the original post I incorrectly stated that the ejector exhaust stack config was a way to tell the difference between the Ki-43-IIc and Ki-43-IIIa. I have edited it with the new info. The sources on this contradict each other somewhat, but I came across a photo today that shows that some Ki-43-IIIa models had their exhaust stacks in a 1/3/1 configuration, which disproves my earlier statement that the Ki-43-IIIa only had a 2/3/2 config. I have included the photo as an attachment on this post, and you can clearly see the exhaust stack config, as well as the set back blast tubes and water-methanol filling port which are both exclusive to the Ki-43-III.

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## rochie (Feb 12, 2021)

Good stuff.

Need to get one or two of these in my model collection

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## taly01 (Feb 12, 2021)

Great photo find, a rare good view of exhausts. Like the tail wheel dolly!

Gakken Ki-43 book says early Ki-43-III used older -Kai style exhaust pipes due to production shortage/development time in making new 2-3-2 pipes. Some photos of late war Ki-43 have mixed equipment that make it hard to determine model.


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## Hardlydank (Feb 12, 2021)

Yeah, finding good photos to use was maybe the hardest part of making this thread, it probably ended up taking several hours, but at least i got to look at tons of Ki-43s


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