The Nakajima Ki-115 Tsurugi (剣, "Sabre") was a one-man kamikaze aircraft developed by the Imperial Japanese Army Air Force in the closing stages of World War II in 1945. The Imperial Japanese Navy called this aircraft Tōka (藤花, "Wisteria Blossom").
The aircraft's intended purpose was to be used in kamikaze attacks on Allied shipping and the invasion fleet expected to be involved in the invasion of Japan, Operation Downfall, which in the end did not take place.
Because the Japanese High Command thought that Japan did not have enough obsolete aircraft to use for kamikaze attacks, it was decided that huge numbers of cheap, simple suicide planes should be constructed quickly in anticipation of the invasion of Japan.
The aircraft was very simple, being made from "non-strategic" materials (mainly wood and steel). To save weight, it was to use a jettisonable undercarriage (there was to be no landing), so a simple welded steel tube undercarriage was attached to the aircraft. This, however, was found to give unmanageable ground-handling characteristics, so a simple shock absorber was then incorporated. The cross section of the fuselage was circular and not elliptical as were most planes of this size and type; such a fuselage was easier to make.
Tsurugi had an instrument panel with some flight instruments; rudder pedals in addition to joystick type control column, and also a place for a radio. Flight controls included both ailerons and elevators and (in production versions) flaps.
The Ki-115 was designed to be able to use any engine that was in storage for ease of construction and supply, and to absorb Japan's stocks of obsolete engines from the 1920s and 1930s. The initial aircraft (Ki-115a) were powered by 858-kilowatt (1,151 hp) Nakajima Ha-35 radial engines. It is not known if any other engine was ever actually fitted.
After testing the first production aircraft were fitted with the improved undercarriage and two rocket units. These may have assisted with take-off or may have been designed for the final acceleration towards the target.
The aircraft had a top speed of 550 kilometres per hour (340 mph) and could carry a bomb weighing as much as 800 kilograms (1,800 lb), large enough to split a warship in two. However, it was otherwise unarmed, and heavily laden with its bomb, would have been an easy target for enemy fighter aircraft.
The controls were crude, the visibility terrible, and the performance abysmal. Tsurugi had very poor take-off and landing performance and could not be safely flown by anyone other than experienced pilots. There were fatal crashes during testing and training. However new, better versions with improved controls and better visibility were under intensive development. The Japanese High Command had plans to construct some 8,000 per month in workshops all across Japan.
The war ended before any flew in combat. Individually, they would have been rather inefficient weapons, but used in waves of hundreds or thousands they could have been quite destructive.
Of the 105 examples produced, two airframes are known to exist. One example of the Ki-115 on loan to the Pima Air & Space Museum in Tucson, Arizona from the National Air and Space Museum. Another, once displayed as a gate guardian at Yokota Air Base, since 1952 turned over to Japanese authorities and is reportedly at a Japanese museum.
Variants:
Ki-115 Tsurugi: Single-seat suicide attack aircraft. production version.
Ki-230: Single-seat suicide attack aircraft. projected version, none built.

THE KIT

This kit hit the shelves in 2004. It was one of Eduard’s great releases back then, creating quite an impact to the modeling world. It was issued in “standard” and “profipack” versions, the profipack differing in the provision of an extra nice PE fret that provides instrument panel, engine lead cables, oil cooler intake mesh, fuel caps and many other goodies. I grabbed mine profipack one at the “normal” price of around 30 euros.
The attractive boxart depicts a non-loaded Tsurugi, attempting to takeoff from (supposedly) Nakajima factory, it being bombed by Allied planes. Its purpose of flight might well have been to ram a bomber (?).
Upon opening the box, one is greeted by three well cast (if not slightly mold-swifted) sprues in beige colour, appearing to incorporate the then new CAD sprue design, with no sink or visible ejector pin marks whatsoever. Since it is a small and very simple plane, there are not a ton of parts, with many of them used for the construction of the well detailed engine and cockpit.
The Tsurugi hd a primitive cockpit and is well represented, with seat (PE belts provided), stick, throttle box with PE cables, foot pedals with PE straps, instrument panel with PE face and extra decal.
Engine is a very well detailed, comprised of 21 pieces, with the PE harness being a nice touch.
The fuselage is typically split in half and, with the cockpit fitted in, sits on top of the two piece wing affair. The horizontal stabilizer is one piece, as is the fin too.
The propeller is nicely done in one piece with extra hub, but the cowling is split in two, inevitably resulting in a seam that needs to be filled and sanded.
The distinctive crude landing gear and extra flaps are satisfactorily executed.
Transparencies look convincing.
Two well done 500kg and 800kg bombs are provided, beefed up by PE rings.
There's a set of masks for the canopy and wheels painting too.
All in all, a very positive first impression of this little strange plane's kit.

CONSTRUCTION

I started with the cockpit. Eduard instructions state a Nakajima green for the cockpit allaround and also for the inner cowling. From what I’ve read and from actual Pima Museum Tsurugi cockpit photos viewed, I sense it is not correct. Floor, stick, throttle box, seat and instrument panel base were made of wood, with minimum treatment (except maybe for the stick looking well varnished…). The pedals' base seems to be made of steel. The cockpit walls look as to have a reminiscent dark greenish tint, which makes me think it was some cockpit green paint lightly applied to the untreated steel cockpit wall, while some other cockpit frames seem to be bare steel.
This makes VERY sense (remember, this was a desperate measure one-off machine). So that is the setup I depicted. I concluded using Humbrol 226 for the green, 110 with minimal clear orange streaks for the “wood” and Testors steel for the rest. Finally, I strongly believe the inner cowling was left bare steel, so on with it too.
So, cockpit was assembled and painted as above. Drilled 6 oval holes to the seat to look like the real one and applied the beautiful PE belts, as well as the tiny photoetched dual cable exiting the throttle box and going forward “towards the engine”.
Fitted the instrument panel. It's detail was raised and OK, but went a bit further on and glued the PE face on top, followed by the decal provided, finally snuggling down to the PE instrument holes nicely (with the aid of my true friend, Mr Mark Softer).
Finished cockpit was trapped between the fuselage parts, them glued to the top of the already assembled wing. Fit was generally good, with only a slight fuselage/wing misalignment, my fault definitely, which was treated with some sanding, with the inevitable loss of some detail. The oil cooler (with nice PE mesh) was also glued in place.
The tailplane was next glued. Fit was excellent. The two supporting rods looked poor, so I replaced them with needle pieces.
The engine was assembled next. It is nicely depicted with front and rear row cylinders and pushrods, augmented by the PE harness. It was painted black and then heavily drybrushed silver. The cowling was assembled/filled/sanded, painted steel inside and received the engine, sans the delicate multi exhausts that were painted Testors burned metal and left apart to be fitted at the final stages.
Other “subassemblies” done were the two flaps, the intricate landing gear legs (interestingly painted in a gun metal-ish colour, as shown in pics, including the tail bar), the two wheels, the propeller (“propeller” brown) and the two bombs (black).
Then it was the filling and sanding session. Filler was used here and there (Squadron green-discontinued- now grey....- green is grey, as my local hobby shop owner points out to me!) only at a minimum, as fit was good (apart from my self induced fuselage/wing slight misalignment).

COLORS & MARKINGS

Painted the antiglare panel black and masked it. Then painted the two side engine panels burned metal and masked them too.
Instructions call for the whole underfuselage bomb open half bay to be painted gun metal. I think this is incorrect, deciding to paint it fuselage color, only the bomb brackets depicted in gunmetal.
The Tsurugi sported steel fuselage, aluminum wings, wooden fin and (possibly) elevators, aiming towards using less and less “strategic” materials, as production line was moving on.
Apart from a small number painted green on top (could only find one pic with one plane), the rest of the planes looked “silver” upon exiting the Nakajima factory, meaning that the wooden parts were painted silver. As for the aluminum and steel parts, due to the desperate circumstances, I believe that they were left untreated.
I wanted to depict a plane that had exited the production line and finished the (say three) test flights, parked inside the Nakajima factory and awaited deployment. So I sprayed Humbrol 11 allover, aiming to tone it down with a black wash (and bring the details up!) later on. Looked acceptable, so I proceeded with the decals.
By studying existing photos, which are rare, the planes seem to wore three “progressing level” camos. Of the 104 or 105 build, most exited the Nakajima factory in NMF with solid red Hinomarus (let’s call it “first” level camo), a few were NMF with green bordered wing top and fuselage Hinomarus (“second” level camo), obviously to assist the green over grey camo to be applied at the field, and a few seem to have their top (at least) with green colour already applied (‘third” level).
I had not seen a lot of Tsurugis modeled with the green bordered Hinomarus and, since Eduard surprisingly provided those, I chose to decal mine like this.
After removing the masking tape and applying a coat of Future (yes, I do it even in NMF, as it protects the “metal” layer from my not so gentle actions...), I started decalling.
Decals went on like a dream, reacting slowly but positively to Mr Mark Softer (kudos to Eduard). I then gave the model a black wash to tone down the shine and bring up the beautiful engraved details (kudos again, Eduard!).
At this time I painted the transparencies. Didn't use the nice masks provided, just hand painted them (why changing the habits of a lifetime??!!).
I did very slight weathering, limited to tyre, “underwing tyre induced” grim and minimal engine exhaust stain, all done with pastels. My scenario of a recently built plane suited me fine, as I am not very fond of weathering.
A final uneven mattish clear coat was finally applied, in order to seal everything.
I installed the landing gear and glued the wheels. Some care must be taken here, as the gluing surface between wheel and hub is minimal and misalignment can easilly occur. Cyanoacrylate is strongly recommended.
The propeller was next fitted, together with a pitot tube at the port wing, fabricated from a needle, as the styrene one was looking less sporty.
Finally the windscreen and canopy were fitted and called this mad beauty done!

CONCLUSIONS

This was a relatively easy and simple kit to build, easily tackled by a novice modeller, who can come with a nice looking OOB Tsurugi.
Of course the advanced (not yours truly) modeler will excel in the NMF and general detailing areas and will produce a masterpiece.
Eduard has to be congratulated for producing this obscure less known plane at this scale and at this quality. Never during the built I had the feeling of dealing with a short run kit. Minor remarks were a slight mold misalignment and the brittleness of some small parts.
The end result looks like a Tsurugi, bringing interesting thoughts in mind about its suicide purpose and how it was implemented at its design and manufacture with scarce suitable materials in the all-pervading desperation climate.

Happy modelling!

REFERENCES

https://en.wikipedia.org/wiki/Nakajima_Ki-115
Various internet sites (photos and info)

KIT #:	8088
PRICE:	30.00 Euros in 2004
DECALS:	one option
REVIEWER:	Spirios Pendedekas
NOTES: