Styrene

Styrene

Wednesday, July 24, 2024

Boeing Monomail model 221 - Dekno 1/72nd conversion

 

Photos from the SDASM photostream 

The sleek, elegant yet imposing lines of the Monomail define this aviation classic. Advanced for its time and yet with a technology that couldn’t keep up to its requirements, only two were ever made. They went through some incarnations starting as model 200, then 221, then 221A. Many things changed along these transmigrations, in an attempt to make it suitable not only for cargo, but passenger-carrying service too.

I have built one of these beauties already from the same Dekno kit, using Arctic Decals masks and set:

https://wingsofintent.blogspot.com/2022/12/boeing-model-200-monomail-dekno-172nd.html

There you may find contemporary articles and following the proper link provided there go to the step-by-step build posting.

This second kit was kindly gifted by John Newcome, one of the many modeling colleagues up north from here, in the Seattle area:

And I really hope that our common friend, the late Jim Schubert, enjoys the build!

John’s hope was that I would plunge into a full conversion to the latest Monomail type, the 221A, which had a much enlarged fuselage and beautiful trousers in one of its guises, plus many other differences, but to preserve whatever little remains of my sanity, already deeply affected, I compromised on the intermediate model, the 221, which had just a minute fuselage enlargement (3.5mm in 1/72nd scale), a slightly different nose, some changes on the wheel and cockpit fairings, plus of course the windows of the now passenger cabin (that still had a smaller mail compartment). Plenty of work already, as you can see. This conversion will give me the opportunity of using the second registration (NC10225) thus not repeating myself.

As mentioned, you can see what the benefits and challenges are regarding this kit looking at the first build. The Monomail is a mid-range release regarding Dekno’s production timeline, therefore being not a shake n’ bake kit, but one that requires a modicum of skills. It can be turned with some care –as demonstrated plenty online- into a beautiful model.

 The usual drill with resin kits. Separating the parts from their pouring blocks:

Washing and then refining them, while fixing the occasional pin hole, resin flash, dimples, pips, etc:

The exterior wing panels are epoxied to the center section after working for a bit on the tongues to achieve a good fit:
Some basic colors applied:
Painting a few details on the interior:

The window positions are measured and the locations drilled and shaped:

The cabin is given a coat of paint. As I have to cut the nose off and add an  insert to slightly extend the fuselage for the 221 model, the interior will later slide-in from the front. This interior will include the seats and the mail compartment at the very front with its bulkhead:

Now a new challenge: how to make those slightly curved windows. Sigh...The usual way is to get a clear container with more or less the same diameter of the fuselage, but I think I will curve an acrylic thin sheet, which I have dome before. We'll see...darn you, John! 😀

Another decision to make: to open the cabin door? or may be one of the three hatches on the top?...

Photos of the 221 depict a more showy painting scheme than the one used on the 200, and also revealed that the original wheel fairings attached to the wing (like the ones in the kit) were not removed at the beginning, but were later substituted by others somewhat similar to the new headrest fairing:

 

The difference in color of the fuselage stripe is just an ortho/panchro rendition of the same scheme:

As mentioned, the "ribbed" nose cone present in the 200 was substituted by one with a number of louvers, another mod needed for the model, as well as some fairing of the exhaust along the fuselage belly.

It took me about 40 minutes to produce a suitable window from bent clear plastic:

Even considering that I may become as I go more able doing this and reduce the time needed, a long boring day would be no doubt ahead. The best part is when you get one almost there, but then it jumps to the Twang dimension, never to be found again:

A coat of primer after working a little on the surface:

All the windows are in (phew!). The fuselage halves are glued together:

The battens on the nose need deleting for this version. Later on the build they will be replaced by resin louvers from Archer:
Once the epoxy is really hard the nose cone will be separated, and extension added, and the cone re-inserted.
Nose off:
A "firewall" disc of styrene is glued to the nose, and then a ring made of a bent styrene stick glued to the it. The sum of both thicknesses resulting in the needed fuselage extension for the 221:

And eventually, after sliding the passenger cabin in, the nose will be re-glued -just tacked here:

The cabin roof needs to be modified, as in reality the hatches had a different configuration (some plans have this mistake). The hatches -that varied in position through the many changes- had nonetheless a generally ovoid shape, something approximately like this, and not straight hinge lines:

The 200 (in this variant the middle hatch was wider):




This photo clearly shows (this is the 221A interior) that again there were no straight hinge lines:

Here are the ends on the other side of the fuselage, no straight lines here either (again 221A):

 And as this Boeing plan shows:

The basic structure of the interior is scratched. The first bulkhead closes the mail compartment, which was in this type at the front:

The 221 -the type being built- had six seats, while the later 221A could seat eight. I have no photos nor diagram of the six-seating, but this below sounds perhaps reasonable, as the access door would be between the firs two rows:

The stabs need pinning, so the locations for the pins are drilled:
Two metal rods are used after drilling the locations:
As the Monomail had a flying stab, the seam should not be smoothed out. The rudder is also in place now:

With a small profile correction in sheet styrene and some Milliput the new shape of the headrest faring is formed. Once the Milliput has set a bit of refining will follow:

The cabin door was carved. The door will be a curved piece of clear plastic with the window masked on both sides before painting the interior and exterior colors:

Minor parts are being readied:

The kit's cabin roof was modified to fit this version (dry-run here). The nose hatch is for the mail compartment:

The new wheel fairings the 221 used are made with sheet styrene and glued in place:

The hatches are made and given a resemblance of their structure with thin stretched sprue:

At this stage the model looks like the Frankenstein monster:


Is ready now for a coat of primer to reveal what needs more work.

Fabricating the Pitot:

Primer:

Before any paint, Archer resin louvers are applied. Remember the kit originally had some radial battens as relief detail, but that's not correct if you want a 221 conversion:

The exhaust on the 221 had a close fairing that filled the gap with the fuselage, perhaps some kind of muff to retrieve heat for the pax cabin:

A coat of French grey is airbrushed, mixing Humbrol 40 (grey) and a tiny drop of 3 (green). I am happy with the result, that matches pretty well with several digital files of the color gathered through the years (all of a slightly different hue of course 😄:


(A pause here whilst a wait for some supplies)


To be continued...