Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual 2–3 Revision 4, March 1, 2002
Sections & Views
Now take a look at Drawing No. 838-2. Here we have something new. In this case there are two
views, but the thing that looks like a side view doesn't make any sense. This is known as a
section .
A section is a view through the part. Returning to our example of the little house, Figure 2 shows
an example of a section.
Figure 2
Because the designer wants to show you something, he has sliced the part in two at the section
line. This is the designer's way of saying “This is what the part would look like if you cut it
through here”. Note the heavy line with two dashes. This is the
section line , and it indicates
where the part is “cut” in two. The arrows on the ends of the section line indicate which way you
are looking at the sliced part. A section may be shown anywhere on the drawing, but the practice
is that a section is never “rotated”. By this, we mean that the top of the part is still shown at the
top. With your hand open, pretend that it is a knife. Bring your hand down on the section line as
if you were cutting the part, then turn your hand so that your palm is facing your face. This is the
way sections are shown. This view will retain its orientation and will be shown elsewhere on the
drawing. A rotated section would result if you turned your hand clockwise or counter-clockwise,
but this is not done in proper drafting practice.
A drafting technique known as hatching is used to indicate the cross-sectional area of the part.
The hatching is the diagonal line pattern, although a pattern of dots may be used as in Figure 2.
Hatching is used in all sectional views, except when the material is extremely thin, as in sheet
metal. To differentiate between two different parts, the hatching pattern is usually changed.
There is an example of this on Drawing No. 720. On this drawing, the section is through the
center of the part, and a section line is not used.
Figure 3
You will also find that in many cases the drawing convention is to show a part in partial cross-
section. Drawing No. 520-3 is an example. This is a half-section. Above the centerline, the part
is shown as a section view, while it is a normal side view below the center line.