Wings of Intent: 1/72 Half-scratchbuilt Japanese Experimental negative aspect ratio plane (based on Nieuport 24 -Nakajima Ko-3)

I simply can't resist the bizarre.

(this is an image I found on the Net many years ago, not sure where it came from now, hope the person that owns it does not mind, for the sake of general interest and Japanese civil aviation)

(the completed model is here:
http://wingsofintent.blogspot.com/2017/01/12-scratchbuilt-japanese-experimental.html

Along the years I have been building some remarkable examples of that aviation strand that provided me with enormous amounts of joy and very exciting hours of research. One of the concepts explored was the negative aspect ratio designs, four of which you can see here:

http://wingsofintent.blogspot.com/2014/07/scratchbuilt-172-scale-dane-hulburt.html

http://wingsofintent.blogspot.com/2014/07/scratch-built-172-mcclary-motorglider.html

http://wingsofintent.blogspot.com/2014/07/scratch-built-172-flick-reinig-apteroid.html

http://wingsofintent.blogspot.com/2016/11/a-2009-build-from-my-archives.html

So, when long ago, I saw on a Japanese site this beauty, I took note and opened a folder for it.

The folder, in spite of my best efforts, remained after many years with only that one photo. My Japanese friends and the Japanese sites I wrote to weren't able to find anything on it.

As you can see this delightful contraption was based on a Nieuport 24, of which the Japanese had many, some in very nice civil liveries for which you can even get decals (Rising Sun, for example, produces a set for J-BAFC). I also found online an interesting photo of three Nieuport 24 that were apparently raced by female pilots for a demonstration (J-BAIF, J-TEIO and J-BAPB), may be for another model down the lane.

After the long wait during which no info came, I decided to give it a go anyway and bought the Nieuport 24 from Roden (Choroszy also produces the Japanese-built version, the Nakajima Ko-3).

The kit from Roden is very nice, in line with their known standards, and as an unexpected bonus you get a bunch of spare parts (engine, props, wheels, stab, rudder, little thingies, etc.) since more than one version is packed in the same sprues. No decals are needed for this project, and that makes things easier (if you don't think on the 234 struts and many parts you have to scratchbuild). In fact, very little will be used from the kit, just the fuselage subassembly minus the bang-bang bits.

Work starts then by intensely staring at the one photo and trying to make sense of it.

A sketch was produced based on the proportions of the many elements and known measures of the kit's fuselage. The plane has two vanes protruding from the mid-line fuselage, a bit ahead of the pilot (acting most likely as ailerons) a "wing" on top of the fuselage and then above it two separate panels for yet another wing. This might thus qualify as a negative aspect ratio triplane.

The Roden kit used as a base:

A sketch is traced:

The Roden kit is very nice and has bags of spare parts:

The quality is good and you get, among other things, two engines:

Flying surfaces detail is subtle:

The engine recess shown here has to be clear of that half-cake seen in the photo for the part that goes in to fit:

The only parts from the kit that will be used (actually tailskid and wheels will be later discarded in favor of other items to match photo):

The center section of the lower wing is needed to hold the cockpit components and close the fuselage, so the panels are separated from it:

Assembly of some groups begins. The center section of the lower wing -cut off- holds the cockpit components:

The cowl is made of two parts (not right and left as usual, but fore and aft). The rudder pedals go on the base seen here for the feet. The engine has parts that allow it to rotate (it's a rotary engine after all) in solidarity with the prop, as it should be. The cockpit has a clever design with some good detail. I prepared a P.E. seat to replace the kit's:

But then I adapted the kit's seat. None of this will be visible as usual when the fuselage is closed:

The build so far. Components and fuselage interior will be painted and then the parts assembled. The real fun will start then scratchbuilding the parts to make the experimental plane shown in the first photo:

Some painting ensues, while the cowl is thinned especially on the vents area:

The kit's engine is quite fair:

But should you feel the need of uncovering your engine or make a diorama, you may want the Rolls-Royce of 1/72 engines, Small Stuff Le Rhone 9J:

The level of detail is almost incredible:

Two crankcases (and a few spare parts, those buggers tend to jump to the parallel universe) are provided depending on the specific version you may use:

Then I glued the fuselage sides. Yes, do not panic, all those other elements can be added later on:

Entrance for the floor, the rudder pedals (with the part that will later close the area) and the engine is just glued by its support to the firewall, rotating if you did things well:

A decal with an instrument face is added to the cockpit:

The is all parts in:

and the cover under the fuselage front:

Some of the parts for the upper structure are in process. General view of the parts. I owe to Andrew Nickeas the kindness of having time ago gotten those brass Strutz and Contrail extruded plastic struts. They are may daily bread for scratch projects (if somebody has more of those Contrail plastic struts and wants to depart from them, I welcome them! I have very little left):

The structure of the "wing" is started. It has an airfoil as any wing:

A window seen in photos is framed and cut out:

The top covering is applied in sections, whilst some imperfections are puttied on the fuselage::

A new tailskid is made to match photo:

And new wheels are made also to match photo:

The "wing" basic shape is ready:

The "kit" is now complete:

Underside of the "wing":

Those vanes seen in photo mid-fuselage are also created, they are linked through a metal pin to "rotate" in the middle. As said before, these may have acted as ailerons:

The new tailskid is glued in position:

The original photo of the plane shows that the struts location has been changed (for both, fore and aft), so accordingly new holes for the struts are drilled on the fuselage. These will match the locating holes underneath the wing:

The struts are very slightly angled on a V configuration (meaning they spread out a bit as they go up to meet the wing). The struts that support the two "upper wings" that also of course run longitudinally are not aligned with the lower struts, but slightly ahead and in different vertical positions (that is, it's not the same struts what unites both wings and the fuselage):

A dry-run of the struts and fit:

The build so far:

Primer is applied:

Different hues of aluminum are airbrushed on:

Four cylindrical objects -of function unknown- that can be seen adjoined to the fuselage in the plane's photo are fabricated:

The landing gear is added, as well as the tail rigging and control cables, and the step:

Parts ready for final assembly:

The mysterious cylindrical objects are added to the fuselage:

The plan
The strange architecture of the flying surfaces posits a conundrum regarding what should be glued to what in order to produce a reasonable, practical sequence of assembly, allowing for alignment, rigging and structural soundness.
I decided to build the "upper structure" separately, starting with the group of central main struts -where the central four and the peripheral four are the same length and horizontal in respect to the datum line:

To those central struts the "upper wings" would be added, and once all was solid the remaining struts could be measured, cut to size and squeezed in without inducing tension or warpage (dry run bellow):

The plan is that once the upper structure is completed (struts painted, all rigged), this would be added to the fuselage via the main four struts. Later on the latter in turn would receive the additional reinforcement struts, be painted and rigged, again paying attention to alignment: