Nakajima Ki-115 Tsurugi

A small single engine, one man airplane.  This was first discovered by the allies after the Japanese surrender, the type was found in scattered hiding places around the Japanese Islands.


What was this airplane that never received an Allied code name?

What were the Allied occupation troops to make of this airplane?  About a hundred were found complete in hiding.  Many hundreds more were under construction.  8000 had been ordered.  Complete examples were powered by a 1150 HP Nakajima engine, but with a provision for a variety of engines to be fitted (especially older, obsolete engines the Japanese had plenty of).  The construction was of wood and steel, non-strategic materials.  The fuselage was tubular, a fairly simple shape to manufacture.  The canopy was only semi-covered.  The landing gear was not retractable; it was jettisonable.  In fact the original landing gear didn’t even have any shock absorption.  The only armament was a single bomb under the fuselage that, unlike the landing gear, was not jettisonable; it was fixed in place.


Total armament is this 800 KG bomb strapped to the underside.


Perhaps its better to think of this as a guided missile.  Or a rather frightening smart bomb.  In early 1945 the Japanese feared their supply of obsolete aircraft might soon be exhausted by their “Special Attack Units” (during the war, only the Imperial Japanese Navy called these units “Kamikaze”.  Post war, it came to be used for all such units).  So the Nakajima company was tasked with providing a very simple air frame made of common materials, that could be fitted with any of the obsolete engines available.  As is so often the case on these projects, the resulting aircraft was very difficult to fly.  And with a maximum speed of 340 mph, that degraded quickly with a bomb or if a lesser engine than the preferred one was used, this plane would have been easy prey for Allied pilots.  So of course the plan was to fill the sky, with hundreds of planes on each mission.




The Kamikaze was a brutally effective weapon.  Almost 3000 such attacks resulted in the loss of around 50 ships and 9000 casualties (all numbers are inexact because sources disagree).  Japan was gearing up in many ways for an expected invasion in late 1945 and there would have been many thousands more Special Attackers had one happened.  Waves of such attackers would have certainly caused many more casualties.  Fortunately, the little Tsurugi (broadsword) was never used in combat.


The subject aircraft, disabled at the end of the war.


This is the Eduard kit of an aircraft found hidden post war.

This is a really small airplane.

This is a really small airplane.

About atcDave

I'm 5o-something years old and live in Ypsilanti, Michigan. I'm happily married to Jodie. I was an air traffic controller for 33 years and recently retired; grew up in the Chicago area, and am still a fanatic for pizza and the Chicago Bears. My main interest is military history, and my related hobbies include scale model building and strategy games.
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9 Responses to Nakajima Ki-115 Tsurugi

  1. Theresa says:

    The Japanese were well equipped to cause massive casualties to the US if they invaded. This plane is one part of that preparation.

  2. Ernie Davis says:

    I find it interesting that once in the air there was no way to change your mind.

    • atcDave says:

      Yeah, changing your mind was not part of the deal!

      The volunteering process for younger pilots was not completely voluntary. Steps were taken to encourage follow through (involving much alcohol in addition to no return aircraft). You have to wonder how many flying accidents there would have been from drunk, low time pilots in a notoriously tricky aircraft! I can imagine mass take offs could have been interesting.

  3. Terry Brodin says:

    Nice presentation of a very simple, but interesting aircraft.
    Interesting that at this desperate phase of the war, time was taken to prepaint around the insignia. I’ve always assumed it was done to facilitate applying the camouflage color later — or was it simply to add contrast with the white outline of the insignia. What’s your take on it?

    • atcDave says:

      Maybe a primer? You’re right it sure seems like an odd choice. I have also seen some fully camo Tsurugis, so maybe you’re exactly right about expecting to apply full paint to this one later.
      Or maybe the meatball painter’s union was really strong… (really, why bother with the insignia at all?)

      • Terry Brodin says:

        I have a camouflage question for you.
        During “Operation Nickle Grass” in 1973, USAF F-4s were ferried to Israel. On arrival, the insignia was changed, but USAF camouflage retained. There are photos to back this up.
        During the same time, 30 A-4E/F Skyhawks (ex US Navy aircraft) were also supplied after a very long ferry flight from the Pease AFB to Israel.
        I have never seen a photo of a Israeli A-4, sporting the Navy grey/white color scheme with Israeli insinia during the Yom Kippur War —- have you?
        Was time taken, either in the US or Israel, to apply camouflage colors over the grey/white scheme?

      • atcDave says:

        You’re way outside my field now Terry!
        It is entirely possible they considered the F-4 to be close enough it required no attention, but the Skyhawks Naval scheme simply had to be “fixed”…
        Or perhaps they came to that conclusion before they even took delivery and arranged for the painting to be taken care of beforehand.
        But bottom line is I don’t know.

  4. Terry Brodin says:

    Just thought you may have run across something about it. Your thoughts are pretty much the same as the conclusion I’ve come to.
    While the USAF camouflage probably was deemed acceptable, retention of the Navy scheme may have brought accusations that the US was directly involved in combat operations with aircraft launched from Sixth Fleet carriers, Independence and Franklin D Roosevelt.
    For the final leg of the flight to Israel, A-4s did in fact launch from the FDR.

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