Fuselage

The term "fuselage" is commonly understood as the body of the aircraft. It is to the aircraft fuselage mounted tail, wings and in some models the chassis. The main purpose of the fuselage is the location of the crew, cargo, passengers and equipment. The fuselage of the aircraft can be placed fuel tank, powerplant and chassis.

The fuselage of each aircraft body acts. It houses cockpit, fuel tanks, depending on the type of aircraft can also be equipped with: luggage, lounge with seating passengers, etc. Scheme plane body consists of transverse, longitudinal members and sheathing. Transverse elements of the power structure housing frames presented, and longitudinal system - stringers and longerons. With regard to plating, it is made of sheet metal, to reduce weight and increase strength is widely used duralumin.

Modern aircraft use girder and truss type fuselage. Previously designed aircraft with frameless - monokovym fuselage. The first such aircraft was created in 1910 year. A special feature was the use of bent tubular ring, which is attached to a curved plywood.

General information about the aircraft fuselage

Fuselage construction serves the basis of each of the aircraft, it allows you to connect into a coherent whole all component parts. Each type of aircraft makes its own demands on the characteristics of the housing, the need to preserve the aerodynamics, the necessary form and minimize weight, without losing the strength of the structure. All this is achieved by:

• The choice of form and parameters of the structure of the fuselage through which you can achieve the minimum drag during flight. Choose useful volume and determine the overall dimensions of the body.

• The enclosure must create lift unit to 40% in integrated circuits aircraft. This reduces weight and wing area.

• Increasing the density of the overall layout allows efficient use of the internal volume and distribution of goods around the center of gravity. Accommodation near the center of mass of goods can achieve the best flight characteristics of the aircraft. Narrowing the range centering device with different arrangements of fuel, ammunition, and their expenditure during the flight must ensure the stability of the machine.

• Sophisticated power circuit layout of the entire aircraft. Thus it is necessary to provide quality plumage mount, power plant, wings, landing gear.

• When servicing of the aircraft should be thought convenient approach to each unit. Easy access of passengers and crew, landing emission bands, loading and unloading, mooring machine. The fuselage must ensure that living conditions for pilots and passengers, namely: normal pressure, sound and heat insulation. For the pilots to be an excellent overview. In an emergency, thought leaving the machine.

The loads acting on the fuselage on landing:

• Forces from attached parts and aircraft parts such as landing gear, wings, tail, power plants.

• Inertia forces units, assemblies, equipment, the total mass of the structure.

• Aerodynamic forces that affect the entire body in flight.

• The pressure in sealed compartments, interiors, and cabin air intake ducts.

All these kinds of loads are taken into account by the principle of D'Alembert, it allows you to bring all the forces in balance.

In structural mechanics housing unit is usually regarded as a box-type beam, which is fixed on the wing and gets all kinds of stresses listed above. This type of fuselage called beamed. Each section of the fuselage affect twisting and bending moment. In an additional sealed compartment overpressure inside.

The main types of aircraft fuselage:

• Ploskofyuzelyazhny type.

• Storey type.

• A two-storey type.

• The wide type.

• Single-aisle type.

The appearance and shape of the fuselage

The most advantageous form of the plane body acts axisymmetric body of rotation which has a smooth narrowing towards the tail and nose. This helps to minimize the area for given design dimensions. Accordingly, it reduced the total weight of skin and minimize friction with the resistance of the fuselage in flight.

The cross section of the circular shape of the body of rotation is most profitable mass under the action of the internal pressure of the pressurized cabin. When creating and layout of aircraft designers depart from this ideal form. Smooth Bypass violate lights cockpit, avionics antenna, air intakes, and the growing weight of the body and the resistance of the structure in flight. In most cases, cross-sectional shape of the aircraft fuselage is dependent on many factors.

Power circuit fuselage

All the loads and forces acting on the body are reduced by reducing the weight of the machine. Thin wall lining the inside of the aircraft has a frame structure, which can withstand all influences. The power of the machine frame can satisfy all requirements of layout, simplicity, reliability and survivability of the fuselage during operation.

Earlier, more common types of truss fuselage were, but they are inferior girder type. It should be noted that the farm greatly complicates the layout and location of goods in the case. In modern aircraft fuselage truss type is only used in small and slow aircraft. By virtue of this type of truss it is unclaimed.

Modern beam type fuselage is divided into the following variations:

• Sheathing.

• Spar.

• Stringer.

The beam fuselage consists of a set of longitudinal stringers and longerons. It should be noted that the main difference is the larger cross-section area and the spar. With regard to the stringers, they have a slightly different shape and a lower section. Sheathing of the hull has no longitudinal members. The body has a cross-set, which is represented by a set of frames. They allow you to keep in shape and design to spread the load around the fuselage. The attachment points of large parts and assemblies such as wings, used type of reinforced frames.

Due to the inner frame plating become possible distribution of loads more evenly over the entire surface of the fuselage. In turn, the external forces bring minimal damage to the integrity of the aircraft.

The power range of the fuselage

Typically, the longitudinal frame parts, such as spars and stringers, extend through the entire length of the aircraft. They are presented as a bent profile with different cross-section of cut. The main objective of the stringer is a load distribution. Regarding spars, they provide the overall stiffness of the structure.

The transverse frame members consist of simple and reinforced frames. They allow you to keep the shape of the fuselage with the external and internal influences. Reinforced frames set near the large openings in the cabinet or in the place of the assembly.

Skin of the aircraft is made of sheet metal, which forms the surface of the fuselage. Boarding the plane is attached to the frame structure. The joints of hull plates located on the longitudinal and transverse parts of the power frame. In modern aircraft construction to reduce the weight of aircraft are increasingly using composite materials.

The connection with the elements of the power trim frame

The aircraft are three basic styles:

• Sheets of skin attached to the stringers. In this case, the housing defines a longitudinal seams of the rivets. This type of attachment greatly increases the aerodynamic properties of the car.

• Leaves skin extremely attached to the frames. Such an option attachment entails an increase in overall structural weight and significant decrease stability of the aircraft. Problems are solved by the use of extra padding, called compensators.

• Sheets of skin attached to the frames and stringers. This type of attachment provides the longitudinal and transverse parts of the power frame.

In most cases the lining is attached to the frame by rivets. Recently, some designers use the hexagonal metallic materials that are inside a special glue. Such fastening withstands deformation processes and transmits the load to the entire surface of the fuselage.

Securing the basic units to the fuselage of the aircraft

Securing wings

Especially compounds of the wing and the body is to balance the bending moment the wing mounting brackets in place. The most effective compound is the balancing between a wing through the fuselage. The wing spar is fairly easy to do, is just to let through the body from one wing to another wing spar.

As for the wing box, then through the fuselage allowed all power panel. In the case where a pass through the body can not use the oscillation circuit on the power frames. To force the frames so often attached and side ribs of the wing.

Fixing keel

Fastening keel, as well as the wing requires the transmission of the bending moment on the chassis. For this purpose the frame or frame grid power. In most cases, mounting spar at two points that are spaced apart on power frames. At the point where intersects the spar with the frames, keel spar has a break, it is necessary to strengthen the structure with additional ribs.

Power plants can be attached both to the frame structure and to the pylon on the wings.

Pressurized compartment in the plane

Due to the presence of pressurized cabins and compartments modern airplanes are able to fly and carry passengers at very high altitudes. In the cab provides a special microclimate with overpressure in 45-60 kPa. Pressurized compartment may have different shapes, but the most rational is considered spherical or cylindrical.

Joint spherical segment with pressurized compartment cylindrical shape frames should be strengthened, as here, an extremely high compressive loads.

The design of the compartments should be provided with excellent sealing rivets at the seams and other joints. For absolute sealing joints using special tapes impregnated with sealant. In addition, the seams coat with a liquid sealant to further baking. Also, a small step between the rivets can improve the reliability of casing and sealing compartments.

Designers pay special attention to sealing hatches, doors, lamps, windows. To do this, use special gaskets, tapes and harnesses. 

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