RU2391251C2 - Aircraft airframe - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to flight vehicles heavier that air, in particular to structural and aerodynamic elements such as aircraft airframe. Proposed airframe comprises skin panels supported by frames. Airframe central part is made cylindrical with oval cross section. Airframe is formed by circular arcs. Along conjugation lines of the latter lengthwise beams to arranged. Said beams are secured in pairs by vertical crosswise struts fitted in the plane of said frames with spacing multiple of frames spacing.

EFFECT: simplified design, lower weight.

2 cl, 7 dwg

Description

The invention relates to aircraft (LA) heavier than air, in particular to structural and aerodynamic elements of an aircraft, such as an aircraft carrying fuselage.

A wide-body aircraft with a bicomponent composite fuselage is known, the central section of which is made in the form of two truncated circular cylinders of equal diameter connected along a chord of a circle using the upper and lower joints connected by a longitudinal wall located in the plane of symmetry of the fuselage (description of the invention to US patent No. 4674712, MKI B64C 1/00 of 1987).

The disadvantage of this invention is the low utilization of volume and lack of comfort for passengers due to the effect of "tunneling" of each of the fractions of the fuselage inherent in narrow-body aircraft. In addition, the presence of a central longitudinal wall in the fuselage makes it difficult to use it for the transportation of bulky goods in the transport version of the aircraft.

It is known the connection of the wing with the fuselage, carried out by attaching the wing box to the power frames of the fuselage. At the same time, the caisson of each half-wing, crossing the side panels of the fuselage skin, is extended inward by a distance limited by the size of the functional compartment, and the upper and lower panels of the caisson of each half-wing are connected inside the fuselage with the walls of the power frames by continuous or multipoint seams (description of the invention to the RF patent No. 2154003, MKI V64C 1/00, 1/26 from 08/10/2000, with priority from 05/18/1998).

A disadvantage of the known design is the limitation of the useful volume of the fuselage by the dimensions of the functional compartment, which reduces the layout capabilities of the fuselage.

The closest technical solution is the carrier fuselage of the aircraft containing the skin panels reinforced with frames (PCT application No. 97/43175 of 05/13/1997 with US priority of 05/13/1996). The last technical decision was made as a prototype.

The disadvantages of the prototype are:

1. The task of the fuselage with a surface of double curvature with variable radii of curvature, which increases the mass of the fuselage and complicates its design, especially in the case of operation of the fuselage on overpressure.

2. The low coefficient of utilization of the volume of the fuselage formed in the longitudinal section by the aerodynamic profile, due to its significant narrowing behind the maximum thickness of the profile, as well as due to the variable height of the fuselage in the area of the payload, which further reduces the comfort in the passenger version of the aircraft.

3. The lack of a cylindrical section in the fuselage, which greatly complicates the organization of additional inserts in the fuselage when developing modifications of the aircraft.

4. Placing the zone of the junction of the wing with the fuselage in the upper part of the bearing fuselage without pairing their surfaces, which reduces the efficiency of transferring loads from the wing to the fuselage and increases the harmful interference resistance.

The technical result of the proposed solution is to eliminate these disadvantages.

For this, the central part of the supporting fuselage is cylindrical with an oval cross section formed by conjugate arcs of circles.

The fuselage design consists of cylindrical cladding panels supported by frames, longitudinal beams located along the mating lines of the cladding panels and connected in pairs by vertical transverse struts installed in the plane of the frames with a step that is a multiple of the step of the frames, as well as the cargo floor.

To connect with the wing, the fuselage power frames in the junction zone have protrusions behind the fuselage contours connected to the wing spars, and the wing skin and fuselage skin panels are smoothly mated.

The technical result of this technical solution is achieved due to the fact that in the proposed fuselage scheme, overpressure loads are perceived by tensile cylindrical skin panels, as in the case of loading the fuselage with a circular cross section, which create a single surface without kinks, providing less weight in comparison with the fuselages of the analogues. In this case, jumps in moments and cutting forces that occur at the junctions of the cylindrical sections of the fuselage surface are perceived by longitudinal beams and transverse struts.

The transfer of loads from the wing to the fuselage is carried out with the help of power frames with protrusions and smoothly conjoined panels of the wing and fuselage skin, as in integrated circuit aircraft.

The invention is illustrated by drawings, where:

- figure 1 is a side view of the fuselage;

- figure 2 is a top view of the fuselage;

- figure 3 shows the conjugation of cylindrical sections of the surface of the fuselage ;.

- figure 4 shows a section along aa in figure 1;

- figure 5 is a section along BB in figure 4;

- figure 6 gives the node D in figure 4;

- in Fig.7 given the node K in Fig.5.

A specific embodiment of the invention is as follows.

The fuselage 1 comprises a central part 2 made cylindrical with an oval cross-section. The surface of the central part 2 is formed by sections of the sheathing panels 3 of single curvature with radii R1 and R2. Along the connecting lines of these sections, longitudinal beams 4 are placed, pairwise connected by transverse struts 5. In the area of the wing 6 to the fuselage 1, power frames 7 are installed, connected with the longitudinal beams 4 and transverse racks 5 and forming a rigid power frame.

Power frames 7 in the zone of junction with the wing have protrusions 10 connected to the side members of the wing 14, and the wing panel and the central part of the fuselage 2 are smoothly mated. The cargo floor 11 is connected with the power frames 7, the lower longitudinal beams 4 and the transverse struts 5 using fittings 12, and the power frames 7 with the transverse struts 5 and the upper longitudinal beams 4 through fittings 13.

Declared for recognition by the invention, the bearing fuselage provides a new technical effect, which consists in:

- weight reduction and simplification of the design of the supporting fuselage through the use of single curvature cladding panels joined along the mating lines with the help of longitudinal beams, reinforced with screeds located in the plane of the frames;

- increasing the utilization of the volume of the fuselage and the level of comfort for passengers, expanding the ability to modify the aircraft due to the presence of the Central part of the fuselage of a cylindrical shape;

- weight reduction, increasing the design life and reducing interference resistance due to the smooth articulation of the wing with the fuselage using power frames with protrusions beyond the contours of the fuselage in the joint area.

The greatest effect from the use of the proposed solution can be achieved for passenger-and-freight aircraft with a sealed fuselage and an average wing position.

Claims (2)

1. The carrier fuselage of the aircraft, comprising skin panels supported by frames, characterized in that the central part of the fuselage is cylindrical with an oval cross-section formed by arcs of circles, along the conjugation lines of which longitudinal beams are installed, connected in pairs by vertical transverse struts installed in the plane of the frames with step, a multiple of the step of the frames. 2. The bearing fuselage according to claim 1, characterized in that the power frames in the zone of junction with the wing have protrusions connected to the side members of the wing, and the wing panels and the central part of the fuselage are smoothly mated.

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