MECHANICAL DRAWINGS AND MECHANICAL DRAWING READING
While mechanical drawings are not a tool in the same sense of a hammer and saws, they indeed are tools in the contribution they
make to completion of a homebuilt airplane. They are drawings which present a picture of parts and assemblies from one or more
viewpoints. Like a written language, mechanical drawings are only useful if the viewer can read them. RV drawings have been
prepared using a blend of accepted mechanical drawing practices and presentations which we feel can be most easily understood
by the average homebuilder. The individual drawings of the respective views show what can be seen from that viewpoint plus, at
times, all hidden lines and features. Looking at the front view shows the presence of hidden lines which can only be clarified by the
addition of one or more views. The side view provides enough information to fully understand the shape of the part. The top view
provides yet more clarification.
Since a mechanical drawing is composed mostly of lines of one form or another, we must define them. Following is a description of
some symbols and lines used.
Solid Line: Represents a surface or an edge which is visible to the viewer.
Hidden Line: Is a uniform line of short dashes representing an edge or surface which cannot be seen by the viewer but is important
to present in the drawing.
Phantom Line: A line of interspaced long and
short dashes shows the position that another part
will occupy at another state of construction or
assembly. It is used to make the builder aware of
the relationship of other parts of the structure,
without the clutter of an assembly drawing.
Bend Line: Indicates the line about which a bend
is to be made.
Section Line: This is used to indicate a view of a
part which could be seen if the part were cut in two
and viewed from the direction of arrows at end of
the line. The letters correspond to the view located
elsewhere on the drawing.
Center Line: Used for the center line of
holes, tubes, discs, and any other part
which is symmetrical on each side of the
center line. This is a series of long and
short dashes.
Detail "X": Denotes that the portion of the
drawing enclosed within the circle is shown
elsewhere in greater detail.
Dimensions: Holes and radius parts are
dimensioned from the center of the hole or
from the center point of the arc describing
the rounded surface. Thus, the overall
height of the part is the base to radius
center plus the arc radius. The overall
height dimension is not usually given, but if
it is, would be listed as a reference
dimension because the other is primary.
PAGE
REVISION:
DATE:
VAN'S AIRCRAFT, INC.
04/15/13
PAGE
03-06
REVISION:
2
DATE:
PLANS PAGE TEMPLATE SCALING
Some plans pages contain templates that are printed at a scale of 1:1. Double check that a plans page is scaled correctly by
measuring the border before using the template! A properly scaled border is shown in Figure 5.
DATE:
0
REVISION:
RV-12
XX-XX
PAGE
02/22/10
PAGE
REVISION:
DATE:
VAN'S AIRCRAFT, INC.
FIGURE 1: ORTHO VIEWS
FIGURE 2: DRILLED HOLE
(NOTE THE POINTED TIP)
FIGURE 3: DRILLED AND THREADED HOLE
(NOTE DOUBLE LINE SEGMENT
INDICATING DEPTH OF THREAD)
10 9/16
16
FIGURE 4: DIMENSIONED PART
FIGURE 5: BORDER DIMENSIONS
ISOMETRIC
VIEW
TOP
TOP
FRONT
SIDE
FRONT
SIDE
℄
℄
1 7/8 [47.3]
R1/2 [R12.7]
Ø3/8 [Ø9.6]
R3/4 [R19.1]
1 1/2 [38.1]
(EXCEPT RV-12)
RV-ALL
