AIRCRAFT NACELLE

Abstract

An aircraft nacelle includes a front portion having an inner wall and an outer wall joined by an annular front frame to delimit a gas passage flow path, the front frame being formed by a plurality of adjacent sheet metal frames which are joined together over at least a portion of the periphery thereof.

Claims

1. An aircraft nacelle comprising a front portion including an inner wall and an outer wall joined by an annular front frame to delimit a gas passage flow path, wherein the annular front frame is formed by a plurality of adjacent sheet metal frames joined to each other on at least one portion of a periphery thereof.

2. The nacelle according to claim 1, wherein the annular front frame includes two adjacent sheet metal frames joined to each other, the two adjacent sheet metal frames including a first sheet metal frame and a second sheet metal frame.

3. The nacelle according to claim 1, wherein the plurality of sheet metal frames include a first sheet metal frame and a second sheet metal frame, wherein the first sheet metal frame has a greater breaking stress and a lower breaking elongation than the second sheet metal frame.

4. The nacelle according to claim 3, wherein the first sheet metal frame is made of Ti-6Al-4V titanium material and the second sheet metal frame is made of T60 grade titanium material.

5. The nacelle according to claim 1, wherein the plurality of adjacent sheet metal frames are adjoined on at least one portion of a surface thereof.

6. The nacelle according to claim 1, wherein the front frame includes a frustoconical inner portion and a frustoconical outer portion, the frustoconical inner portion and the frustoconical outer portion being connected by a middle portion having a curvilinear profile, wherein the plurality of adjacent sheet metal frames are adjoined in the frustoconical inner portion and frustoconical outer portion, and are spaced apart in the middle portion with the curvilinear profile.

7. The nacelle according to claim 1 further comprising an inner connecting angle connecting the front frame with the inner wall and an outer connecting angle connecting the front frame with the outer wall, wherein at least one of the inner connecting angle and the outer connecting angle includes a plurality of sheet metal pieces.

8. The nacelle according to claim 7, wherein the inner connecting angle includes a plurality of sheet metal pieces and the outer connecting angle is formed of a single sheet metal piece.

9. The nacelle according to claim 1 further comprising an annular lip extending upstream of the front frame in reference to a direction of flow in the gas passage flow path, wherein the annular lip is fastened to the front frame by lip connecting angles.

10. The nacelle according to claim 9, wherein the lip connecting angles are common with a corresponding inner connecting angle or an outer connecting angle.

Description

DRAWINGS

[0026] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0027] FIG. 1 is a schematic perspective view of a nacelle front portion according to the present disclosure;

[0028] FIG. 2 is an enlarged schematic cross-sectional view according to the plane II of FIG. 1;

[0029] FIG. 3 is an enlarged view of detail III of FIG. 2; and

[0030] FIG. 4 is an enlarged view of detail IV of FIG. 2.

[0031] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[0032] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0033] With reference to FIGS. 1 through 4, the front portion of the illustrated nacelle includes, in a manner known per se, an annular inner wall 1 and an annular outer wall 2 joined by a front frame 3 to delimit a gas passage flow path V.

[0034] In the following description, the terms inner and outer are used with reference to a radial direction of the nacelle. Also, in a manner known per se, the front portion comprises an annular lip 4 sealingly fastened to the front frame 3.

[0035] According to the present disclosure, the front frame includes a plurality of adjacent sheet metal frames, which in this form includes a first sheet metal frame 6 and a second sheet metal frame 5 joined to each other along the periphery thereof. In the illustrated example, the two sheet metal frames 5 and 6 are made of Ti-6Al-4V titanium. The first sheet metal frame 6 can be made according to different configurations in order to improve the capacities of each frame related to the load. For example, the first sheet metal frame 6 can be made of a material with a high breaking stress, but a limited breaking elongation (for example Ti-6Al-4V) to absorb increased energy from the obstacle such as a bird strike before breaking, while the second sheet metal frame 5 is made of a material with a high breaking elongation (for example T60 grade titanium material) to allow a significant plastic deformation providing a retention of the bird.

[0036] In the illustrated example, the front frame 3 includes a frustoconical inner portion 7 and a frustoconical outer portion 8 connected by a middle portion 9 having a curvilinear profile.

[0037] In the frustoconical portions, the first sheet metal frame 6 and the second sheet metal frame 5 are adjoined while, in the middle portion having a curvilinear profile, the first sheet metal frame 6 and the second sheet metal frame 5 are spaced from each other by a distance just sufficient to allow an assembly of the first sheet metal frame 6 and the second sheet metal frame 5 without prestressing. In practice, the spacing between the first sheet metal frame 6 and the second sheet metal frame 5 in the middle portion 9 is on the order of manufacturing tolerances of shaping the first sheet metal frame 6 and the second sheet metal frame 5, which in one form is a few tenths of a millimeter.

[0038] On the outer side, the first sheet metal frame 6 and the second sheet metal frame 5 are connected to each other and to a first wing/flange 10 of a V-shaped outer connecting angle 11 by rivets 12. The outer connecting angle 11 is formed of a single sheet metal piece and includes a second wing/flange 14 to which, on the one hand, the annular lip 4 is fastened by rivets 13, and on the other hand, the outer wall 2 is fastened by rivets 15. It should be understood, however, that the outer connecting angle 11 may be formed of a plurality of sheet metal pieces.

[0039] On the inner side, the first sheet metal frame 6 and the second sheet metal frame 5 are glued/bonded to each other, and to a first wing/flange 19 of a V-shaped inner connecting angle 16 which includes two sheet metal pieces 17 and 18 glued/bonded to each other (also referred to as lip connecting angles). These lip connecting angles 17/18 may also be employed as an outer connecting angle while remaining within the scope of the present disclosure. The V-shaped inner connecting angle 16 includes a second wing/flange 20 which is fastened to the annular lip 4 by rivets 21, and to the wall 1 by an annular sheet metal piece 22 forming a strut between the second wing/flange 20 to which it is fastened by the rivets 21, and the wall 1 to which it is fastened by rivets 24 by bearing on a shim 23.

[0040] Of course, the present disclosure is not limited to the described form and is capable of variants without departing from the scope of the present disclosure as defined by the claims.

[0041] In particular, although the nacelle, according to the present disclosure, has been described in relation to a front frame including only two associated sheet metal frames, it is possible to carry out the present disclosure with a front frame including three associated sheet metal frames or even more if desired to obtain a front frame having a particularly high impact resistance while reducing the additional sheet metal weight involved to obtain it.

[0042] Although the present disclosure has been described in relation to a form comprising an outer angle including a single sheet metal piece, it can be carried out with an angle including several adjoined pieces of sheet metal.

[0043] Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word about or approximately in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

[0044] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean at least one of A, at least one of B, and at least one of C.

[0045] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.