Compass: A Guidance Tool

Contributing Editor: Joe "vecojoe" Wagner

Third Installment In This Series

The purpose of any type of scale model airplane, whether it's a "
No-Cal" indoor rubber - powered craft or a quarter - scale R/C project, is to
resemble the full-size original well enough to "look real" to spectators
and judges. And the first aspect of that resemblance that anyone notices
is the
color scheme of the model.

Trying to achieve a realistic model airplane color scheme has probably
led to more misunderstandings and misguided effort than any other
aspect of scale model building.

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Joe Say's "Brilliant" Spitfire

Let's get down to the basics:
The way "
real" airplanes are painted.

Any kind of paint consists of two major elements, called the
Vehicle and
Pigment. No, the Vehicle isn't a machine with wheels. It's the "liquid plastic" that coats the surface, and in which the Pigment is suspended.
And Pigment is the
coloring agent.

Up until a few years ago, all paint Vehicles tended to become
yellow with time. Some, such as linseed oil, varnish, and shellac, were yellowish to start with; then darkened with age. Others, such as lacquer and clear dope, were relatively clear when "new" but yellowed with time and exposure to sunlight.

That's why
ALL painted aircraft finishes (up to the introduction of acrylic lacquers around 1965) had a more or less yellowish tinge. And that's why stark white areas in scale model aircraft insignia never look quite realistic. "Real" airplane "insignia white" was always faintly cream-colored.

Now for the Pigment! Here's where misunderstandings proliferate. First, there are several completely different types of Pigment used in airplane finishes. Only a few are "permanent" -- that is, unaffected by time or sunlight. All others eventually
fade or change hue. None intensify!

I once owned a fire-engine-red station wagon. In less than two years of exposure to southern California sunlight, the finish faded to a dull
brick red. According to Col. Robert Johnson (the WW2 Thunderbolt Ace),
exactly the same thing happened to the Oklahoma-built Wiley Post
biplane he learned to fly in. When new, that machine was as brightly red
as a ripe tomato. But after a year or so the finish had lost its vividness.
Col. Johnson described it as a dark,
rusty red...

Most of the "stable" pigments are metallic oxides. "
Earth colors" such as Siena (made from soil found near that Italian city), Umber, Yellow Ochre, Aquamarine, and Lamp black are permanent. They've been employed by artists over the centuries for just that reason. Permanent reds, yellows, oranges, greens, and blues exist too -- but those have always been far too expensive for painting large objects. Aquamarine, for example, comes
from finely - pulverized semi - precious gemstones.

Cheaper pigments are common. Speaking of reds alone, there's cochineal, carmine, rose madder, oxblood, red lead, red iron oxide... But the bright,
vivid reds (such as cochineal) are "fugitive". They soon fade into obscure pinkish browns. Red lead and iron oxide are permanent all right -- but nowhere nearly as intense in hue as, say, catsup...

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Hadley Hudnall's JU87

The point I'm making here is that the pigments used in airplane paint
have always been chosen more for low cost & ready availability than for permanence or stability. Not only that: very few paints contain only a
single pigment. Except for black, white, and aluminum, nearly all
colored aircraft finishes contain a blend of miscellaneous pigments,
varying degrees of permanence.

And that introduces another variable! Until recent times, paint colors
were blended "
by eye" or by formulas approximately as precise as a
recipe for sourdough bread. Pigment quantities were measured by the
pound or by the bucketful. Imprecision was especially common during wartime, when getting the job DONE took precedence over artistic perfection.

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Scale Aero and Details 1998