HOW TO MODEL WITH CAD
of other parts) on a separate layer named
“Plan.” Details such as the engine, servos, and
other radio gear go on the “Hardware” layer,
and so on. I even add my dimension lines,
arrows, and information on their own layers.
In this way, you can look at specific items by
turning layers on or o;, or you can look at
everything all at once. ;is helps keeps things
straight in your head.
USE REFERENCES. Start all plans by drawing
a datum line, centerline, or other reference
line on the fuselage side and top views. From
this, you can ensure that things like ribs and
formers are drawn square with (or parallel to)
one another. Vertical and horizontal reference
lines also are important when you develop
fuselage cross-sections and former shapes.
THINK SYMME TRICALLY. When it comes to
things like wings and fuselages (in top view),
draw only one half and then copy and paste
a mirror image of it to complete the drawing.
Do all your work on one side of the centerline,
then duplicate it and flip it over to produce the
other half. ;is ensures exact symmetry and
cuts your drawing e;orts in half!
SAVE DETAILS. One clear benefit of CAD is
that you won’t ever need to draw anything
twice. Once you draw something like an
engine, electric motor, servo, receiver, or
control horn, save it to a master “Hardware”
file. After you have saved them, you can then
copy and paste them into new plan drawings.
You can also enlarge, shrink, or modify them
to make new master details. (Drawing them in
top, front, and side views also is a good way to
hone your overall drawing skills.)
USE THE TOOLS. ;e Tool palettes included
with all CAD programs are a collection of several
useful drawing tools and functions. It is always
easier to use these tools than trying to draw
freehand over your imported 3-view drawing.
Geometric drawing tools for circles, squares,
ellipses, and arcs are all easy to use, and using
them will make your drawings look cleaner
and more precise. Wingtips, engine cowls, and
other parts are easily reproduced by combining
segments of ellipses, curves, and straight lines.
WORK INWARD. After you’ve drawn your
reference and centerlines, draw the outline of
a wing half top view, fuselage side view, tail
surface top views, and half of the fuselage top
view. From here, you then
establish the locations of
the main formers, doublers,
landing-gear mounts, wing
spars, ribs, and so on.
the many sources of
downloadable airfoil plots,
or consider getting an
airfoil generator program.
;ese will save you hours
of tedious airfoil layout and
lofting work. Above all else,
remember this is a hobby,
so using CAD should be—
above all else—fun!
DRAW FULL SCALE. Once
you have your 3-view
traced and cleaned up,
enlarge the drawing to
the size airplane you want
to build before you add
any internal structures or
details. ;is way, when you
draw an 1/8-inch-thick
For some airplanes, like this Pietenpol Air Camper, you may not be able to find a good set of 3-views. ;is plane was based on one from years ago at
the Old Rhinebeck Aerodrome. To produce my own 3-views, I measured the actual airplane and took a lot of photos.
TYPICAL RC HARDWARE
I think the best part of drawing with CAD is that it eliminates the
need to draw anything twice. Once you’ve saved your files, you never
have to draw those items again! Here are just a few RC hardware
details I’ve drawn that I use over and over.