Boarding the plane
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Boarding the plane

Boarding the plane

 

Boarding the plane - shell and feathers forming the outer surface of the body of the aircraft. It is necessary for the aircraft to sleek. From how much quality will paneling, it depends largely on the aerodynamic performance of the aircraft.

Material sheathing

Modern aircraft lining is made from panels or individual sheets of aluminum alloys (or titanium and stainless steel) molded on the surface of the wings or fuselage. Fixed panels or sheets are most often attached to the frame by blind riveting, removable panels are connected with screws with a head "vpota". Sheeting sheets are joined end to end. Often, for coiled fuselages, coarse-finned finned panels and a sheathing layer with a honeycomb core are used. The radomes of antennas (radio-transparent elements of the skin) are made of honeycomb or monolithic composite material. Also recently, composites have been used as sheathing panels and power units.

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Depending on the material used for the construction of aircraft trim the aircraft can be:

  • metal: steel, aluminum alloys, titanium;
  • wood (or plywood);
  • perkalnaya (linen);
  • composite materials;
  • laminated film.

The history of the aircraft skin

The first aircraft had a lining made of a fabric that is impregnated with varnish (hence, in fact, there was the name), fuselages and often do not have the skin. Later trim started making wood - plywood and veneer, which are also impregnated with varnish.

With the development of technology lining was made of aluminum, smooth and corrugated. Today is used exclusively smooth metal paneling. However, in light aircraft can still be found fabric covering. This is extremely rare, as it effectively replaces the polymer films.

 Types of skins

In aviation, there are two types of skin - soft "non-working" and hard "working." Nowadays the advantage is a hard metal covering, as it fully meets the requirements of strength, aerodynamics, mass and rigidity. It perceives loads in the form of twisting and bending moments, external aerodynamic loads and loads of shear forces acting on the frame of the aircraft. Materials for the production of working sheathing: titanium, aluminum and steel alloys, aviation plywood, composite materials. Titanium and steel are most often found in the construction of supersonic aircraft.

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Non-power trim is not included in the power circuit, as the load with skin immediately transmitted to the frame. Material for its manufacture can serve percale (cloth).

Wing skin

Depending on the type of construction sheathing and feathering of the wing can be thick, consisting of monolithic machined or molded panels, thin-layer and, supported by a special dial stringer. In this case, space is mezhobshivochnom special filler (cell foam, foil or special corrugations). It is important to trim the wing kept a predetermined shape and was tough. The formation of folds in it provokes drag.

The upper covering of the wing under the action of the bending moment is loaded with cyclic compressive forces, and the lower one, respectively, with tensile forces. For this reason, for upper compressed panels, as a rule, high-strength materials are used, which perfectly demonstrated themselves to compression. In turn, for the lower stretched skin, materials with high fatigue characteristics are used. The cladding material for supersonic aircraft is selected taking into account the heating in flight - conventional aluminum alloys, heat resistant aluminum alloys, steel or titanium.

Boarding an old airplane

To increase the strength and vitality of skin along the length of an aircraft wing the number of joints, have a shorter life compared to the main canvas skin, seek to minimize. Weight wing skin - 25-50% of the total weight.

fuselage Skin

Immediately it should be noted that it is selected according to the current load. Lower plating zone receives the compressive load of the portion which is attached to the stringers, and the top takes the tensile forces across the area of ​​skin completely. Thickness of cladding in a sealed fuselage is selected depending on the internal overpressure. To improve survivability in the skin of the fuselage often use tape-stoppers, excluding crack propagation.

Connection casing and frame elements

To resort to the three methods of connection frame with a shell:

  • lining is attached to the frames;
  • lining is attached to the stringers;
  • lining is attached to the frames, and stringers.

In the second case, only longitudinal riveted seams are formed, while the transverse ones are absent, which has a positive effect on the aerodynamics of the fuselage. Unfixed sheeting on the frames at lower loads loses stability, which increases the weight of the structure. In order to avoid this, the lining is connected with an additional pad (compensator) with the frame. The first method of attachment is used exclusively in stringless (cladding) fuselages. 

A honeycomb panel is attached to the frames. It includes a core and two metal panels. Cellular construction - a material of hexagonal type, consisting of metal. In the core there is glue, which allows not to use rivets at all. This design is capable of transmitting stress over the entire surface and is characterized by high resistance to deformation. 

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