Dummy Engines for Scale Models |
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by
George Kandylakis
(Feb 16, 2004)
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In
response to questions from fellow SFA
Forum members, I decided to write this short
article about the dummy engines in my models. I
hope it will serve as an inspiration or a starting
point for anyone who wishes to try something more
detailed.
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Albatros DIII 1/20 scale. Engine is only cylinder
head assemblies, together with piping. Removable
2nd cover for charging the CO2 engine. (cylinder
below 1st cover)
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I am by no means an “expert”, but
these techniques have been helpful to me in detailing
small scale models. Sometimes what works for one
is useless for another, so the reader will have
to take what is useful to him and ignore the rest.
My own first steps for dummy engines were based
on Bill Hannan’s “Peanut Power”
book, an inspiration for peanut models and scale
free flight in general. Practice and experimenting
afterwards helped build up some experience and
at some point I realized that nearly every type
of engine was feasible. It only takes time and
patience.
And a little more time.
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Most every airplane has an engine (or parts
of it) exposed. I like airplanes mainly
from the pre-1914 period when everything
was visible - even the pilot’s socks!
Most of my “serious” modeling
projects had an exposed engine. I feel it
adds much to the model’s character
and draws a lot of attention. It is perhaps
the only place where extra detailing really
pays off, even in an otherwise simple model.
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1912 Avro F peanut with static prop
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The first step towards creating a detailed dummy
engine is to know what you are building - i.e. the
actual engine itself. Good documentation is the
key here, and the starting point for everything.
A good drawing is necessary, as are pictures, preferably
in color and at various angles. For old types this
may seem impossible, but it is amazing what can
be found through museums. My personal experience
with the Science Museum of London
and the N.A.S.M., to name only
two, turned up unexpected results for very rare
types.
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Real engine (Beardmore I think) at the Science
Museum of London. Full of various parts, screws
etc.
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After finding a drawing, resizing it to the
actual model size is the next step. Photocopiers
or scanners make quick work of this.
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Photographs are necessary for two reasons: first
they give a better view of the powerplant and
it’s components, and second they show
the colors of the various components. This variety
of materials and colors is what makes an engine
look real, instead of a one-tone metal shade.
Even in black and white one can see darker cylinders,
polished copper intakes, black exhaust etc.
Next comes the first real difficulty - you have
to think out the major components for the engine
and how to make them as raw components. Ignore
all the minor stuff and think only in terms
of main "volumes”. Usually the crankcase
will be the main component to which the cylinders
will attach. Then there are cylinders, cylinder
head covers, manifolds, pushrods, etc.
For all the major components balsa is my favorite
choice. Balsa is great to shape and to sand,
and of course it is very lightweight. The only
drawback is the grain, but this can be filled
with thin coats of dope and in-between sanding.
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For all cylindrical components it is necessary to
turn them on a “lathe”. A simple Dremel
type tool with a suitable chuck will do fine. My
setup is very simple: an RC pushrod end with a balsa
disk glued on, and sandpaper glued to the disk. |
Turning base for balsa components
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To shape a cylindrical part I take an oversize
balsa block and drill a hole slightly smaller
than the rod thread. I then put a very small
quantity of Cyano inside the hole and screw
it into the rod, making sure it doesn’t
get stuck. This way a thread is formed and the
block is firmly screwed to the drill. Now it
can be shaped with a variety of tools - an X-acto
knife (carefully, with goggles and never against
the direction of rotation), sanding block, emery
board, or any other suitable tool. After the
shape is achieved, the surface is doped 1-2
times to seal the pores. Large areas can even
be covered with tissue for that purpose.
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To
connect cylinders to the crankcase I create a mechanical
connection in addition to glue. Basically this is
just a bamboo or hardwood peg connecting the two
parts, which protects against the shock of crashing.
I use this approach with all connections. A small
dowel coming out of one part is always pushed into
a hole in another part to make a strong connection.
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word about cylinders. Either the engine is water
cooled or air cooled. For the former you need a
very smooth surface to simulate copper or steel.
The aircooled cylinders are more of a problem, but
my favorite approach is the two-thread method. This
is done by wrapping two pieces of thread around
the cylinder and gluing them down with dope. Once
the wrapping is completed, wait a few minutes and
unwrap only one of the threads. What's left is an
evenly spaced thread wrapped on the cylinder. Apply
more dope to seal everything. The effect will be
further enhanced during painting. |
Farman Moustique “sport” model.
Cylinders are balsa with thread wrapping. Dry
brushing enhances depth.
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