Wednesday, March 26, 2014

Scratchbuilt 1/72nd scale Northrop Avion "Flying wing"

-This is the building article, the finished model can be seen here:
http://wingsofintent.blogspot.com/2014/04/scratchbuilt-172-northrop-avion-flying.html

To boldly avion where somebody has gone before:

Flying wings are a particularly attractive subject among modelers of a certain breed. There were also test beds and midway concepts, like the Junkers G-38 and the Northrop first "flying wing", that were not pure flying wings (had tailbooms and tail surfaces) but a cautious approach to the concept. Although Jack Northrop is erroneously credited by some for having either invented or developed the concept (he did neither), the history of the flying wing stretches far beyond.
Interestingly enough, the particular stressed-skin, all-metal flying wing depicted here (the "Northrop" Avion 1) started as a concept pioneered by one of Northrop's associates and later employee, Tony Stadlman. It was him that started Northrop on the thread, although Jack later appropriated his work and even had the face to get mad at Stadlman. Northrop was a great contributor to aviation development on his own right, but the flying wing was not his idea, not even "his" flying wing was his idea. Stadlman was an immigrant from Czechoslovakia that also contributed to the engineering and construction (he was a co-filer of the patent) of Lockheed's monocoque structures.
Be this then an homage not to Northrop (by the way, once more, it is not "Northrup" as erroneously and extensively written in many places), but to Stadlman, the original thinker behind this particular concept. On the Net you may find photos of him holding a model of his flying wing, if you see a remarkable similarity between his and Jack's flying wing, it is NOT a coincidence.
The Avion went, as many prototypes do, through a number of modifications. The horizontal stabilizer is seen in a few images with a portion outside the vertical stabilizer, more according to patent drawings, but was later trimmed back. Extra portions of surface were added to the vertical stabilizers and ailerons, and also to the stab leading edge, which is seen passing beyond the fins' leading edges; the engine was installed as a pusher (prop behind) and a tractor (prop in front), the taildragger tricycle landing gear started as a retractable unit but very soon adopted the simplicity of a fixed one, and therefore the landing gear legs and struts were changed. The Avion could fly two, but the right position was faired over. Photos show also the minor changes introduced to accommodate the aft or front prop. A windshield can be seen too in some images. Bear all this in mind if you decide to build one, and use photos as references. As it is almost always the case with these oddballs no plans whatsoever or not good ones at any rate could be found, so I modified a plan from the Net using photos and the given measures.
The construction techniques are more or less the same ones generally used on the models in this blog, although the unusual shape called for a slightly different approach engineering-wise this time. The attached photos as usual will give you a good idea of the "hows" and the "whats". The Avion is a relatively small model in 1/72nd scale, so it requires a bit of care and attention. Home-made decals were produced (this time around fortunately only simple registrations) and after-market wheels and prop used.
Strange shape, perky stance, shinny surface, historical significance, all make for a nice model if you have the will to go a bit further into the magic lands of scratchbuilding.
See you there.

A "kit" is made before starting assembly:
 Some modules already in progress:
More structure is added:
The tail parts are assembled and the bucket seats are ready:
The three modules that constitute the wing center are individually wrapped:
The center section:
A view of the "modules":
 The complex geometry of the central body was solved. The ribs are relatively thick, so minor adjustments can be made to render a proper dihedral. Once the "wing" is assembled, the cutouts for the tailbooms will be made:
Some details (headrest fairing, propeller aft-shaft fairing) are made but left aside until the body is put together and smoothed-out:
A wood block is marked to later cut the nose of the model. Once carved a vacuformed part of it will be attempted. A very simple representation of the engine to put inside the nose:
Decals are printed and the nose wood plug is ready:
 A vacuformed part is made from the plug and the necessary cut outs performed:
Some other miscellanea is prepared as the main parts dry, in this case the prop and instruments decals and the exhaust stubs:
 The main components are glued, puttied and sanded, bottom view:
 Top view
 The nose is dry-fitted:
 The tailbooms are glued and aligned:
 Then the stab is added:
Cut-out to make room for the engine, headrest and fairing added:
The tricycle landing gear installations begins by marking and drilling locations and positioning the aft wheel:
Then it is completed:
The small little thing:
The engine is glued and the nose will follow, like with the real thing:
Here is with the nose already on:
At this stage painting can begin starting with a black base:
The first coat of aluminum paint is airbrushed, needless to say, the shine will be toned down later on:
Panel hues are represented by decals treated with diverse metal types, thus avoiding masking. Later on a very light coat of an equalizing shade will be applied, and the shine toned down:



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