FRAME ASSEMBLY FOR A REAR SECTION OF AN AIRCRAFT AND REAR SECTION OF AN AIRCRAFT COMPRISING SAID FRAME ASSEMBLY

Abstract

A frame assembly for a rear section of an aircraft, comprising at least one frame having a plane of symmetry, wherein the frame assembly also comprises at least one supporting element having two ends, wherein each one of the ends is attached to said at least one frame at different sides of the plane of symmetry. This arrangement permits a more effective transfer of loads coming from the vertical tail plane of the aircraft to the fuselage.

Claims

1. A frame assembly for a rear section of an aircraft, comprising: at least one frame having a plane of symmetry, at least one supporting element having two ends, wherein each one of the ends is attached to said at least one frame at different sides of the plane of symmetry.

2. The frame assembly according to claim 1, wherein each one of the ends of the at least one supporting element is attached to a side of the same frame.

3. The frame assembly according to claim 1, wherein said at least one frame defines a medium geometrical plane perpendicular to the plane of symmetry, and the least one supporting element is placed above said medium geometrical plane.

4. The frame assembly according to claim 1, wherein the at least one supporting element is placed in a plane perpendicular to the plane of symmetry.

5. The frame assembly according to claim 1, wherein said at least one supporting element comprises auxiliary elements for fixing a vertical tail plane.

6. The frame assembly according to claim 1, wherein the at least one supporting element has a flat configuration.

7. The frame assembly according to claim 5, wherein each auxiliary element has an upper area to be attached to a vertical tail plane and two lower supports, each lower support to be attached to adjacent supporting elements.

8. The frame assembly according to claim 1, wherein said at least one frame has an upper discontinuity in the upper area, wherein the at least one supporting element is attached to the frame so as to cover such an upper discontinuity.

9. The frame assembly according to claim 5, wherein said auxiliary fixing elements comprise fittings.

10. The frame assembly according to claim 8, comprising a plurality of frames and longitudinal longerons that are placed between adjacent frames.

11. A rear section of an aircraft comprising a frame assembly according to claim 1, comprising a vertical tail plane that is attached to the frame assembly by said at least one support element.

12. A rear section according to claim 11, wherein rear section comprises auxiliary elements including fittings having an inclined surface directly attached to spars of the vertical tail plane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a better comprehension of the invention, the following drawings are provided for illustrative and non-limiting purposes, wherein:

[0019] FIGS. 1a, 1b and 1c schematically show a solution of the state of the art regarding the VTP attachment in a rear section of an aircraft wherein shear joints are used; FIG. 1a shows a transverse section of a frame wherein the load transfer has been represented by arrows, FIG. 1b shows a perspective view of the VTP attachment and FIG. 1c shows the arrangement of fittings for the attachment of at least one frame in the tail cone structure to the VTP.

[0020] FIGS. 2a and 2b show two perspective views of the arrangement between frames of the shear joints schematically shown in FIGS. 1a, 1b and 1c, in the tail cone structure, wherein FIG. 2a includes the skin and FIG. 2b does not include the skin and the frames can be appreciated.

[0021] FIGS. 3a, 3b and 3c show an alternative solution of the state of the art regarding the VTP attachment in a rear section of an aircraft wherein tension joints are used, wherein FIG. 1a shows a transverse section of a frame wherein the load transfer has been represented by arrows, FIGS. 3b and 3c show the arrangement of the tension joints, in the VTP in FIG. 3b, and in the skin of the tail cone structure in FIG. 3c.

[0022] FIG. 4 schematically shows a transverse section of a first embodiment of a frame assembly according to the invention, showing how it works for a pure moment load case, i.e., the loads coming from the VTP are transmitted to the supporting element to the frame in such a way that the frame is under a pure moment load case.

[0023] FIG. 5 schematically shows a perspective view of a rear end in which the frame assembly according to the first embodiment shown in FIG. 4 has been installed.

[0024] FIG. 6 shows a perspective view of the supporting and auxiliary structural elements of the first embodiment shown in FIGS. 4 and 5.

[0025] FIG. 7 schematically shows a transverse section of a frame wherein a second embodiment of the invention has been represented, in which the supporting element is placed in a top position, so the auxiliary structural elements are reduced to only fittings.

[0026] FIG. 8 shows a perspective view of the second embodiment shown in FIG. 7, where longerons stabilizing the supporting element are shown and wherein the supporting element is placed in a top position, so the auxiliary structural elements required are minimized to only fittings.

[0027] FIGS. 9a and 9b show two opposite perspective details of a third embodiment of the invention wherein the spars of the VTP are used for its attachment to one frame of the tail cone of the aircraft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] As depicted in FIG. 4, in a rear section of an aircraft, the vertical tail plane (1) has a plane of symmetry (4) and is operatively connected, e.g., by means of bolts, rivets or metallic fittings, to at least one supporting element (3) acting as a beam and having two ends (3), wherein each of the ends (3) of the supporting element (3) is attached or clamped to the same frame (2), having also the same plane of symmetry (4) of the VTP. This plane of symmetry (4) is the vertical plane of symmetry, i.e., when the plane of symmetry perpendicular to the ground when the aircraft is on the ground.

[0029] In turn, each of the ends (3) is located at a different side of the plane of symmetry (4) of the vertical tail plane (1) when attached to the fuselage.

[0030] Preferably, according to a first embodiment depicted in FIGS. 4 to 6, the supporting element (3) has a flat configuration, i.e., formed by a plate. According to the first embodiment, the ends (3) are greater than the central area in order to better resist the loads in the attachments to the frame (2), as can be appreciated in FIG. 5.

[0031] Each of the ends (3) of the at least one supporting element (3) is attached to an inner side (2) of the same frame (2). As can be appreciated in FIGS. 4 and 5, each attachment between the ends (3) and the frame (2) is located in a half space closer to the VTP (1) defined between the VTP (1) and a medium geometrical plane (6) of the frame (2) perpendicular to the plane of symmetry (4). Given the orientation of the elements forming the structural configuration of the invention, the supporting element (3) acts as a horizontal beam.

[0032] The at least one supporting element (3) is perpendicular to the plane of symmetry (4), and the vertical tail plane (1) is operatively connected to the at least one supporting element (3) by means of auxiliary elements (5).

[0033] As shown in FIGS. 5 and 6, the auxiliary element (5) has a rectangular upper area configured to be attached to the VTP (1) and two lower supports, each lower support being configured to be attached to adjacent supporting elements (3).

[0034] According to this embodiment, the auxiliary element (5) has a rectangular upper area configured to receive the vertical tail plane, and two lower supports, each of them being operatively connected to one supporting element (3). Preferably both supporting elements (3) are adjacent, placed opposite each other. In turn, each of the supporting elements (3) can be formed by two plates and each lower support can engage between the two plates, the connection being made by means of riveting or bolts.

[0035] FIGS. 7 and 8, show a second embodiment, representing the extreme case of the first embodiment wherein the supporting element (3) has been elevated to its maximum position. In the second embodiment, the at least one frame (2) has an upper discontinuity in the closest area to the vertical tail plane (1), wherein the supporting element (3), formed by a rectangular plate, is attached to the frame (2) so as to cover such a discontinuity.

[0036] The at least one supporting element (3) is perpendicular to the plane of symmetry (4), and the vertical tail plane (1) is operatively connected to the at least one supporting element (3) by means of auxiliary elements (5) comprising metallic fittings.

[0037] According to the second embodiment longitudinal longerons (8) are required, whose purpose is to connect the planes of the frames (2) affected by the introduction of this concept, in order to transfer the longitudinal load and avoid big deformations in X direction. These new parts are necessary due to the absence of contact between the upper skin and the frames. In the first embodiment represented in FIGS. 5 and 6, this job is done by the auxiliary elements (5) connected to the supporting element (3).

[0038] FIGS. 9a and 9b show the third embodiment of the invention, where the VTP (not shown) is joined to at least three frames (2) of the tail cone through its spars (7) of the vertical tail plane (1). According to the third embodiment, the auxiliary elements (5) comprise metallic fittings having an inclined surface directly attached to the spars (7) of the vertical tail plane (1). Although in the first and third version of the invention the schemes show a pinned joint, riveted joints can be considered as well for the connection between the fittings or the VTP extension to the supporting element (3).

[0039] Additionally, in order to avoid the kink between the supporting element (3) and the VTP spars (7) (third embodiment), the supporting element (3) and frames (2) to which the supporting element (3) is connected can be slanted in order to make coincident frames planes with the VTP spars planes.

[0040] In the third embodiment, longitudinal longerons (8) may also be required for the same purpose as in the first embodiment.

[0041] Thus, the main components of the proposed invention are:

[0042] the supporting element (3), whose main task is to react to the loads and send them to the right and left hand sides of the structure in shear direction;

[0043] auxiliary elements (5), such as metallic fittings or composite panels, in order to transfer the loads from the VTP to the aforementioned supporting element (3);

[0044] and, for the second and the third embodiments, additional longitudinal longerons (8) to connect the planes of the frames (2) affected by the invention, in order to transfer the longitudinal load and avoid large deformations in X direction.

[0045] The invention impacts in several engineering parameters with respect to current known solutions:

[0046] Weight. The invention allows an overall weight decrease given by frames and skin, although there is a smaller addition of the supporting elements (horizontal beams) and/or the auxiliary elements (VTP extensions).

[0047] Manufacturing and assembly processes: The highly complex machined High loaded frames (HLFs) are replaced by new simpler composite elements (supporting elements, C or Double C Frames, auxiliary elements . . . ). Because of carbon fiber reinforced plastic (CFRP) design, one way assembly processes can be targeted for the whole rear fuselage section, which reduces significant assembly time and therefore provides a recurring cost reduction. Additionally, in the second version of the concept (with VTP fittings) there is no connection between the skin and neither the fittings nor the frame/supporting element in the upper area, so the assembly operations in this zone are simplified.

[0048] Materials: All main structure in this concept could be made of CFRP. So, no thermal loads and therefore weight decrease.

[0049] Maintainability: No inspections are needed for CFRP elements. Metallic fittings do not have any accessibility problems.

[0050] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.