The Fuselage

 

The Fuselage

I) The Fuselage

A. Materials of the aircraft's shell.

 


 

Before starting, we have to know that, at the beginning of aviation, aircrafts were entirely designed of wood, for then evolve slowly to a structure in Aluminum so as to take off weight (between 1920's and 1930's). Like the DOUGLAS DC2 in 1933, for example.

In the 1940's, the aerodynamic properties know a great growth, that's why Aluminum becomes more and more used. Then, with the appareance of brand new types of jet engines which are kept under temperatures more ? than we knew before ?, we note the ? of a brand new material : the ?. This one ? ? in several places of the aircraft as aircraft engines or ? (his first ? was with the DOUGLAS DC7 in 1957). But, in the 1970's, ? ? of Aluminum, others materials are used in the ? places of the airplane to ? like plastic or ? ? for example.

 

Which materials, and for which parts of the airplane ?

1) the Wing.

Wings support strength which allow to maintain the airplane during flight. Under theirs effects, wings have tendancy to bend high. That's why, the top part of the wing is loaded of ? whereas the bottom part is loaded of ? . However, it must also supports torsion loads. So, we use an alloy of Aluminum for the top part, because it has great mechanical aptitudes in ? and stability. For the bottom part, we use another alloy of Aluminum more tolerant in view of wear/tear and structural damages. Leading edges, trailing edges and wing's components, are themselves in materials composites.

2) the Fuselage

Fuselage's structure is designed by developer so that answer to many technic demands because it is kept under multiple loads like : 

  • flexion loads
  • torsion loads
  • pressurization resistance loads
  • located loads (impact when touchdown) 

At the beginning , fuselage was constituated of Aluminum-copper alloy which was used for a long time (It also allows to point impact from lightning). However, now, it has been replaced  by many others alloys more resistant, always  ? Aluminum or Kevlar (but which costs more expansive).Nevertheless, in the future, we will use rather a material like Glare which should appear on the A380's fuselage soon ; it's a material constituated of Aluminum and compistes ultra resistant and very light .


 

 

 

 

3) Jet Engine

  Jet engines must present an high efficiency thermodynamics, for a mass of the engine the lighter possible. It means that engines have to be very powerful all in being relatively small. We attract materials ? for theirs realisation. To optimize the efficiency, it lead us to raise power gas' temperature (from the combustion), the materials temperature which constitues the engine raise so much... Thus, we have to choose some materials very resistants to the heat. But the necessity to reduce the mass conduct idea men to materials which have density as weak as possible.

 

- The choice of materials angles to : 

  • High-performance alloys for the rotating metallic parts, which interact with gases (before or after the combustion chamber): superalloys with first-class, poly-crystalline for disks and single-crystal for dawns.
  • New alloys with weak densities, but very refractory for parts of crankcase for example: the intermetallic compounds.
  • And composite materials

 

4) Porthole and landing gears

- Portholes are constitued of two attached windows, the internal window is constituted by polymer (kind of plastic) and the internal part is constitued of mineral glass (that is it is very resistant).

- Landing gears are, as for them essentially in titanium.

 

B. The fuselage shape

The fuselage indicates the envelope of a plane which receives generally the transported load, as well as the crew. The fuselage of a plane supports the buckle, the empennage (for the stability).

The shape of a fuselage is studied to reduce its aerodynamic trail, where from its name,which comes from the verb "to fuseler" which literally means "making narrow". Its shape thus follows the rules of aerodynamics, except for ancient planes, and for the seaplanes which possess a bottom of fuselage in the shape of planante shell to land on the water.

  • Certain light planes, ulm or autogyres, have a not slender longitudinal structure, a beam or a wire-mesh ?

 

  • There are devices in two identical parallel fuselages : Savoia-Marchetti S-55 ( 1925 ), Twin Mustang.

 

  • There are devices in three identical parallel fuselages(both side fuselages being different from the central fuselage) : P38 lightning. 

 

 

  • Finally, certain rare machines as Vought XF5U " Flying Pancake " contain only one fuselage without wings; the portance is assured by the shape of the fuselage (which is a wing of very weak elongation).

 

 

 

 

 

 (Helicopters possess generally a partial fuselage the back of which is a beam or a structure in wire-mesh)

 

 

 

 


 

 

 


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