The Journey of Flight.pdf - Valkyrie Cadet

welded in place to form a well-braced
framework as shown. Long lengths of tubing
called longerons characterize the basic form.
Welded to these longerons are vertical and
horizontal struts which give the structure a
square or rectangular shape as viewed from one
end; however, this isn’t enough bracing. Other
struts must be placed so that stresses coming
from all directions are resisted. Thus, struts at
various angles to the longerons and horizontal/
vertical struts are necessary. Imagine how the
truss structure could be twisted, bent, stretched,
sheared and compressed. This is how the total
structure performs its job.
The truss structure is not a streamlined
shape. Before the skin is added, something must
be done to make the structure a streamlined one
or the aircraft will have a form drag problem.
The Basic Truss-type Fuselage Structure
Additions to the basic truss structure can be
added. The label bulkhead may also be known
as a “former,” but in either case, if the addition is to give shape to the fuselage, it will have stringers
attached. The purpose of these stringers is to support the covering that will go over the fuselage.
Monocoque is a French word which means single shell. The true monocoque construction depends
on the covering or skin to provide the
required strength to resist the stresses of
flight. True monocoque construction like
that illustrated in the picture to the right is
not common. The semimonocoque is the
most often used approach for highperformance
aircraft.
The semimonocoque construction uses
internal braces to help the skin carry the
forces generated. Semimonocoque literally
means half a single shell. The internal
braces include longitudinal stringers and
vertical bulkheads or formers.
The semimonocoque structure is easier
to streamline than the truss structure. Since
the skin of the semimonocoque structure
must carry much of the fuselage’s strength,
it will be thicker at those points where the
stresses on it will be the greatest.
Semimonocoque and Monocoque Fuselage Structures
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