Aotake and Ambiguity
It can't be a surprise that military modelers like military museums. Toss in an interest in traveling and you get to see some things. Sometimes the same things. Sometimes different things. And sometimes, the same, but different things.
Take "aotake", that mysterious word in the title of this post. I have seen it represented during my museum travels, but it always seems...different.
Enough rambling. What is aotake, why was it used, and importantly, how can it be recreated in scale model form?
What is aotake and why was it used?
To answer this question, let's focus on the most famed Japanese aircraft of World War II: the Mitsubishi A6M Zero. The Zero is the product of a 1937 Imperial Japanese Navy request for a carrier-based fighter that combined maneuverability at least equal to the current carrier-based fighter, the A5M, and the range to escort bombers on missions into China. To achieve these requirements, the Zero had to be extremely light.
The requirements were so difficult to meet that of the two principal Japanese aircraft manufacturers, the Nakajima Aircraft Corporation and the Mitsubishi Aircraft Corporation; only Mitsubishi thought it was possible. Their solution was to use a new lightweight aluminum alloy developed by Sumitomo Metal Industries in 1935. It was called "extra super duralumin". But there was one problem, it was prone to corrosion.
Enter the anti-corrosive coating known as aotake, or loosely, "green bamboo", which was applied to the Zero's internal metal structures. Ironically, aotake is naturally clear. Various pigments were added to facilitate its uniform application. And because there was no standard pigment formula, aotake appears in a beautiful palette of colors.
It's that color palette that made me think, "Gee, I need to paint that!"
Aotake at the museum
Here are three different A6M Zeros, from three different museums, from three of my travels:
A6M2 Type 21 located at the National Museum of the United States Air Force in Dayton Ohio.
A6M2 Type 21 at the Pearl Harbor Aviation Museum in Honolulu, Hawaii.
A6M5 Type 52 at the Yushukan Museum in Tokyo, Japan.
From a historical point of view, it is important to remember where these Zeros are all located. Museums. They have been restored in one way or another. Sadly, much of the original paint, and yes, aotake, would have been scraped off and replaced. In other words, the aotake that we are seeing, probably isn't even aotake!
Despite this, we can probably still learn a thing or two about aotake. Let's take a closer look at what each museum had to offer.
National Museum of the USAF
Here is the first example of where aotake is applied that is visible to us modelers. Namely, inside the wings, on the inner surfaces of the flaps, and in the landing gear wheel wells. You can also make out that the smaller landing gear doors are covered in aotake, but not the main covers. Importantly, and according to the museum, this is a Nakajima-built A6M2 Type 21 Zero, not a Mitsubishi-built one, painted to represent an aircraft at the Battle of the Bismarck Sea in March, 1943.
Alright, hang on, Nakajima dropped out of the fighter design competition and the Zero is synonymous with Mitsubishi! Yes. However, the demands of war meant that Nakajima had to build Zeros too. And this is part of the reason Zeros are the same...but different!
Pearl Harbor Aviation Museum
Here is another Nakajima-built Zero. It is painted to represent a famous Mitsubishi-built A6M2 Type 21 Zero that took part in the raid on Pearl Harbor on December 7th, 1941, and crash landed on the Hawaiian island of Niihau. This Zero example has landing gear wells that are painted in aotake, but not the landing gear doors or the main covers. Additionally, the "Type 21" Zeros had folding wingtips. The Zero at the USAF museum shows this off, while the Zero at the Pearl Harbor Museum doesn't appear to have this feature. That's the thing with restored aircraft, sometimes entire structures have been rebuilt or grafted from other Zeros.
Whatever, Zero plus Zero still equals Zero!
Lastly, we have an A6M5 Type 51 Zero. No aotake. I guess this is a Zero...but different!
Where do the museums leave us?
Where does the internet leave us?
I'll spare you all the rabbit holes coated in aotake that I have gone down researching this topic (well, some are linked at the bottom of this post) and give you my interpretation of the internet's consensus. Zeros used on December 7th, 1941, to attack Pearl Harbor did not have aotake applied to their landing gear wheel wells, doors, or covering panels. Why? Because these Zeros were built by Mitsubishi, and Mitsubishi did not do that. Nakajima, which didn't start production of the Zero in earnest until 1942 did paint the wheel wells and landing gear doors and covers with aotake. Why? Because they did. Relating this explanation back to my sample Zeros:
The Zero at the National Museum of the USAF appears to show aotake mostly in line with Nakajima-built Zeros, except they may have wanted to paint the main wheel well covers with aotake.
The restorers at the Pearl Harbor Aviation Museum may have incorrectly painted the wheel wells with aotake if they were trying to represent a Mitsubishi-built Zero. But they also might know something we don't.
As for the A6M5 at the Yushukan, all bets are off. Most articles I have found about it are in Japanese, and yours truly does not read Japanese.
Just tell me how to paint it
Here are three different ways to paint aotake with Tamiya Acrylics in order of increasing difficulty.
1) Per the instructions on Tamiya's 1/48 scale A6M2 Type 21 Zero legacy kit, use X-13 Metallic Blue straight from the bottle.
2) Per the instructions on Tamiya's more modern 1/32 scale A6M2 Type 21 Zero kit, use 3-parts X-13 Metallic Blue and 1-part X-25 Clear Green.
3) Per the fun way. The way that mimics how it was really done. And the way I am going to build my A6M2 Type 21 Zero.
Lay down a base coat of XF-1 Flat Black or X-1 Black. Metallic colors look better over black.
Then, lay down XF-16 Flat Aluminum.
Now, just like the real deal, spray on a mixture of X-23 Clear Blue, X-24 Clear Yellow, and X-25 Clear Green. I used an approximate 3-parts X-23 Clear Blue to 1 Part X-25 Clear Green ratio. Experiment as you like.
You see, aotake. The same...but different!
Editor's note: It is interesting that two different Tamiya Zero kits had two different paint formulas for aotake. It is also interesting to read some inconsistencies in their instructions as it relates to Nakajima-built zeroes being at Pearl Harbor and painting Mitsubishi-built Zero landing gear wells and covers with aotake. But let's not dwell on the wells, shall we? Aotake is ambiguous enough!
Given all the pixels I have just allocated to a discussion of aotake, and your newly acquired expert knowledge, you wouldn't be remiss for thinking that I am building a Nakajima-built Zero. I hear you saying it: "Mido, you have aotake in the wheel wells and on the landing gear covers. That means it's a Nakajima-built Zero!"
All I can say is that it's my model and I am building a Zero with Pearl Harbor markings which means it must be a Mitsubishi-built Zero!
Understandably, my Zero will just have to be...different.
Thanks for reading,
Sources, information, and other useful links
Contact the author: firstname.lastname@example.org or on IG @igluemodels