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Williams Brothers 1/8 Wright J-5 "Whirlwind" engine - Part 3 by Rogério ´Rato´ Marczak As mentioned in Part 2, I was looking for a different metallic color for the missing details in order to avoid a too monotone look. I took my old tin of Humbrol Metal Cote Polished Steel (#27003) and tried it on a piece of scrap. I just have forgotten how good this stuff is. It dries as a flat dark gray with a very light metallic hue. After a couple of passes with a cotton swab, the shine comes out exactly like the color name states. So I used this color for a number of smaller parts (levers, caps, and some nuts). Interestingly, because you can´t reach all depressions and recesses of some parts, the result is an attractive effect with higher areas shining and the others remaining dull (sometimes you don´t even need to polish it - the handling of the parts takes care of it). No need of washing!
Then it was time to
finish off some major subassemblies. The accessory drive case was
the first. After glueing the missing parts (fuel pump, oil pumb
and some blank-off plates), I couldn´t resist to make a very
light dry-brushing using the Humbrol Polished Steel.
The next one was the
carburetor. I painted the levers (parts #63 and #64) with Polished
Steel attached them, and then gave the same treatment of the crankcase
accessory drive. And by the way, these parts (the levers) don´t
match their corresponding shafts. You have to englarge their openings
to make them to fit.
As for the carburetor
air heater, I cemented six nut/studs to the lower side of the mounting
flange and treated the area with a heavy wash.
The carburetor was
then cemented atop the air heater. The whole set will be later butt-glued
to the flat area below the intake manifold.
The intake manifold was
installed under the intake distribution housing. It was a very problematic
fitting. Even after flattening the intake ends, they didn´t
match the outer and center flanges (parts #30 and #31) very well.
I waited until the cement was dry and washed the area very heavily
with a black/brown oil paint mixture to dissimulate the remaining
gaps. Be aware that there is an oil suction pipe (part #54) connecting
the drive accessory case with the base of the intake manifold. Fortunately,
the pipe is attached in the holes of separate flanges (parts #55).
I glued the accessory case flange in place but left the one which
goes on the intake manifold for later. This will afterwards allow
me to find the correct location of the intake flange using the oil
pipe itself as a guide. The accessory drive case
was butt jointed to the rear of the crankcase, but the carburetor/air
heater set was left to the end.
Next, I had to install
all 18 rocker boxes atop the corresponding flat spots on the cylinders.
These parts must be positioned very carefully to allow each pushrod
ends to touch their pad section and the rocker box simultaneously.
I could choose to install the cylinders, then the pushrods, and
at last the rocker boxes, but it would be almost impossible to keep
a good alignment for all 18 pushrods. I started assembling the rocker
boxes on one of the cylinders with regular cement. While the cement
was still wet, the cylinder was dry fitted to one of the crankcase
openings and the position of the rocker boxes adjusted to match
the pushrods spacing. Once the glue has set, I used this cylinder
as a pattern to glue all remaining rocker boxes on their cylinders.
Don´t forget that
the longitudinal alignment of the rocker boxes is also critical.
Since the cylinders will be mounted side by side, any deviation
here will be visible. I traced some parallel lines on a piece of
white paper and used it as an alignment device during this step.
All you have to do is to position the cylinder so that the spark
plugs remain visually aligned with one of the lines. Then, while
the glue is still web, check if the rocker boxes are also parallel
to other lines, and correct if necessary. They are not finished,
though, as there are still the 36 arm grease fittings to be glued
on the sides of the rocker boxes.
At this point it become
clear that the handling of the model would be a major issue. So
I made a jig out of acrylic plates and installed the engine with
its mount using small screws. The jig allows 360 degrees rotation
so that I can reach all cylinders with the same easiness. Moreover,
you can make use of gravity while the glue is setting...
Since the kit´s
rubber ignition harness loom was discarded, I removed the corresponding
locating pins around the crankcase bolt ring plate. Later I will
drill small holes to accept the scratchbuilt loom.
I inaugurated the jig
installing the cylinder bases (seats). Nothing difficult here, but
a hint of the seam line remained visible between each base. Fortunately,
the area will be almost invisible after the cylinders are in place.
I decided not to install the cylinders now. I´m afraid they
will prevent reaching some location where I forgot something...
it always happen to me. I also discovered that
the magneto advance pivot rod (part #10) can´t be inserted
in the hole I made! I have to enlarge the hole, but will left the
part to be installed later.
The instructions clearly
mention that one of the intake pipes is made of rubber because the
plastic (straight) ones won´t by-pass the intake manifold.
Since I´m not going to use any rubber parts, one of the plastic
intakes was bent to properly clear the intake manifold. Here is
a good hint to produce very localized bents in plastic parts: I
use a steam immersion-heater of an old capuccino machine (no, it
doesn´t work anymore - for capuccinos, I mean). Just keep
the part under the steam jet for some seconds and bend the part
before it cool dows. Watch your fingers here - steam is hot - better
to hold the part with pliers. This thechnique works wonderfully,
and enables a more precise work than immersing the whole part in
hot water, because you control where the heat acts (the rest of
the part remains hard).
 A simple way to bend plastic parts. If your equipment also delivers capuccino, even better (mine doesn´t anymore). Before setting aside the cylinders, I washed the spark plugs area. I always waste more oil paint than the necessary trying to reach a good color tonality. A fellow modeler (who build figures) gave me a hint: a color called `Natural Shadow´. It is very good indeed. When in doubt, that seems to be the color to use...  Washing those areas looking ´too fresh´. I´m really enjoying this project. By now the part trees are empty, and this beast is starting to look like an aircraft engine. |
