Transition of beams across common base loads

Abstract

The present application relates to a stringer transition portion that passes through a common base load. The construction of the stringer transition portion that passes through a common base eliminates the need for panel fittings and their associated fasteners to connect the opposite ends of a first stringer having a larger cross-sectional area to a second stringer having a smaller cross-sectional area. A composite base is secured to a skin panel of an aircraft wing, the base being aligned with and extending along the longitudinal length of the skin panel. A first stringer is secured to the base, and a second stringer is secured to the base, the first stringer and the second stringer being longitudinally aligned with the base with a longitudinal spacing between the first stringer and the second stringer. The base connects the first stringer to the second stringer, and it is only the base that connects the first stringer to the second stringer.

Description

Technical Field

[0001] The present disclosure relates to an aircraft structure, such as an aircraft wing, constructed of a composite material and reinforced by stringers that run the length of the wing. Because the stringers run the length of the wing, as the wing extends from its inboard end to its outboard end, its cross-sectional configuration changes due to the reduced interior area of ​​the wing. Background Art

[0002] In a typical configuration of an aircraft wing, a rib box is formed in the interior of the wing. The rib box extends along the longitudinal length of the wing between the inboard end of the wing and the opposite outboard end of the wing. The rib box is positioned transversely between the forward edge or leading edge of the wing and the rearward edge or trailing edge of the wing.

[0003] The wing rib box contains a plurality of ribs extending transversely between the forward spars of the wing rib box and the rearward spars of the wing rib box. The plurality of ribs are longitudinally spatially arranged along the longitudinal length of the wing box. The wing box construction also includes a plurality of stringers extending longitudinally through the top and bottom of the wing box. Stringers are elongated, narrow reinforcements that extend along the longitudinal length of the wing box and are fixed to the ribs in the reinforced wing box. The stringers are also connected to the top outer skin panel of the wing and the bottom outer skin panel of the wing.

[0004] Because a typical aircraft wing tapers as it extends from its inboard end to its outboard end, the internal volume of the wing box decreases as the wing box extends from its inboard end to its outboard end. As the internal volume of the wing box decreases as the wing box extends from its inboard end to its outboard end, the space between the front and rear spars of the wing box for the stringers in the wing box decreases. This requires that at some point along the longitudinal length of the wing box, each stringer must run out or terminate, or transition from a first cross-sectional area of ​​the stringer to a second cross-sectional area of ​​the stringer, where the second cross-sectional area is smaller than the first cross-sectional area. This typically requires that a first stringer having a first cross-sectional area terminates and then begins again as a second stringer with a second cross-sectional area. The first stringer is connected end to end to the second stringer.

[0005] When a stringer transitions from a larger first cross-sectional area stringer to a smaller second cross-sectional area stringer, the first stringer and the second stringer must be connected end to end. This connection is typically provided by a plate fitting connected between the opposing ends of the first stringer and the second stringer. For example, where the first stringer and the second stringer have an "I" shaped configuration, the plate fitting is attached between the webs at the opposing ends of the first stringer and the second stringer, and the plate fitting is attached between the top flange and the bottom flange at the opposing ends of the first stringer and the second stringer. A material typically used to construct the plate fitting is titanium. The titanium plate fitting is attached between the opposing ends of the first stringer and the second stringer by a plurality of fasteners.

[0006] The use of titanium plate fittings and a plurality of fasteners to connect the opposing ends of the first stringer and the second stringer significantly increases the construction time of the wing box. In addition, the use of titanium plate fittings and fasteners to connect the opposing ends of the first stringer and the second stringer significantly increases the weight of the wing box. The use of titanium plate fittings and fasteners also significantly increases the cost of constructing the wing box. Summary of the invention

[0007] The aircraft structure or aircraft wing of the present disclosure is constructed with a skin panel that extends the longitudinal length of the wing. The skin panel has an outer surface and an opposite inner surface. The outer surface of the skin panel forms the outer surface of the wing that is exposed to the external environment of the wing. The outer surface of the wing can be the top surface of the wing or the bottom surface of the wing. The longitudinal length of the skin panel extends between the inner edge of the skin panel and the opposite outer edge of the skin panel. The skin panel has a transverse width extending between the front edge of the skin panel and the opposite rear edge of the skin panel.

[0008] The base is secured to the inner surface of the skin panel. The base has an elongated, generally rectangular and generally planar configuration. The base has an outer surface and an opposite inner surface. The base has a longitudinal length extending between an inner side edge and an opposite outer side edge of the base. The base has a transverse width extending between a forward edge of the base and an opposite rearward edge of the base. The outer surface of the base is secured to the inner surface of the skin panel, wherein the longitudinal length of the base is aligned with and extends along the longitudinal length of the skin panel.

[0009] A first stringer, such as a cap stringer, having a first cross-sectional area is secured to the inner surface of the base. The first stringer has an outer surface and an opposite inner surface. The first stringer has a longitudinal length extending between an inner end of the first stringer and an opposite outer end of the first stringer. The first stringer has a transverse width extending between a forward edge of the first stringer and an opposite rearward edge of the first stringer. The outer surface of the first stringer is secured to the inner surface of the base, wherein the longitudinal length of the first stringer is aligned with and extends along a portion of the longitudinal length of the base.

[0010] A second stringer having a second cross-sectional area, such as a blade stringer, is also secured to the inner surface of the base. The second stringer has an outer surface and an opposite inner surface. The second stringer also has a longitudinal length extending between an inner side end of the second stringer and an opposite outer side end of the second stringer. The second stringer also has a transverse width extending between a forward edge of the second stringer and an opposite rearward edge of the second stringer. The outer surface of the second stringer is also secured to the inner surface of the base, wherein the longitudinal length of the second stringer is aligned with the longitudinal length of the first stringer, and wherein the longitudinal length of the second stringer is aligned with and extends along a portion of the longitudinal length of the base.

[0011] There is a longitudinal space between the first and second beams. No fittings (e.g., titanium fittings) are used to span the longitudinal space between the first and second beams and connect the first and second beams. Instead, the base connects the first beam to the second beam, and only the base connects the first beam to the second beam.

[0012] The configuration of the stringer transition eliminates the need for titanium plate fittings and their associated fasteners to connect the opposite ends of a first stringer having a larger cross-sectional area to a second stringer having a smaller cross-sectional area. Additionally, the stringer transition configuration does not require titanium plate fittings and their associated fasteners to connect the first stringer having a larger transverse width to the second stringer having a smaller transverse width. The connection between the opposite ends of the first and second stringers at the transition is provided solely by the base.

[0013] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of an aircraft wing of the present disclosure utilizing stringer transitions across a common base load.

[0015] Figure 2 It is along Figure 1 The line 2-2 is located in the plane passing through Figure 1 Schematic diagram of a cross section of a portion of a wing.

[0016] Figure 3 It is along Figure 1 The line 3-3 is located in the plane passing through Figure 1 Schematic diagram of a cross section of a portion of a wing.

[0017] Figure 4 is an illustration of a cross section through a smaller circular cap stringer.

[0018] Figure 5 is an illustration of a cross section through a blade stringer.

[0019] Figure 6 is an illustration of a plan view of the first step in the construction of a stringer transition across a common base load.

[0020] Figure 7 is an illustration of a plan view of another step in the construction of a stringer transition across a common base load.

[0021] Figure 8 is an illustration of a plan view of another step in the construction of a stringer transition across a common base load.

[0022] Fig. 9is an illustration of a plan view of another step in the construction of a stringer transition across a common base load.

[0023] Fig.10 is an illustration of a plan view of another step in the construction of a stringer transition across a common base load.

[0024] Fig.11 is an illustration of a plan view of another step in the construction of a stringer transition across a common base load.

[0025] Fig.12 is an illustration of a plan view of another step in the construction of a stringer transition across a common base load.

[0026] Fig.13 is an illustration of a front view of a stringer transition across a common base load.

[0027] Fig.14 is a flow chart of a method of constructing a stringer transition across a common base load. DETAILED DESCRIPTION

[0028] exist Figure 1 An aircraft structure using several stringer transitions passing through a common base is illustrated in FIG. 1 , which is the subject of the present disclosure. Figure 1 The aircraft structure 12 is shown as an aircraft wing. However, the concepts of the present disclosure of stringer transitions through a common base can be used in a variety of different types of aircraft structures. The stringer transitions through a common base are composed of components constructed of composite materials. More specifically, these components are composed of pre-impregnated, fiber-reinforced composite materials. Other equivalent types of materials can be used in the stringer transitions through a common base.

[0029] exist Figure 1 , Figure 2 and Figure 3 In the configuration of an aircraft wing 12 schematically illustrated in FIG. 1 , a wing box 14 is formed in the interior of the wing. Figure 2 The diagram shows the Figure 1 A cross section of the wing box 14 in the plane of line 2-2 and in Figure 3 The diagram shows the Figure 1 A cross section of the wing box 14 in the plane of line 3-3.

[0030] refer to Figure 2 The interior of the wing box 14 includes a rib 16 extending between a forward spar 18 and an aft spar 22. The rib 16 is also connected to a skin panel 24 forming the bottom outer surface of the wing 12 and a skin panel 26 forming the top surface of the wing 12.

[0031] A pair of lower stringers 28 extend along the longitudinal length of the wing 12 from the inboard end 32 of the wing toward the outboard end 34 of the wing. Figure 2 As shown, the lower stringer 28 has a narrower cross-sectional area and a narrower transverse width. An example of such a stringer 28 is a blade stringer. Figure 5 A schematic diagram of a cross section through a blade stringer 28 is shown in FIG. Figure 2 The ribs 16 and the inner surface of a lower skin panel 24 forming the bottom surface of the wing 12 are shown.

[0032] A pair of upper stringers 36 extend along a portion of the longitudinal length of the wing 12. The pair of upper stringers 36 have a larger cross-sectional area than the pair of lower stringers 28 and a larger transverse width than the pair of lower stringers 28. An example of such stringers 36 is a cap stringer. Figure 4 A schematic diagram of a cross section through the cap beam 36 is shown in FIG.

[0033] Figure 3 It is along Figure 1 Schematic diagram of a cross section through the wing box 14 in a plane oriented along line 3-3. Figure 3 , an additional rib 42 is shown. The additional rib 42 extends along the longitudinal length of the wing box 14 from Figure 2 The rib 16 is shown positioned toward the outboard end 34 of the wing box. An additional rib 42 also extends between the forward spar 18 and the aft spar 22 of the wing box 14. The skin panel 24 forming the bottom surface of the wing 14 is connected to the bottom edge of the additional rib 42, and the skin panel 26 forming the top surface of the wing 12 is connected to the top edge of the additional rib 42. The pair of lower stringers 28 extend through the additional rib 42 and connect to the additional rib 42 and the skin panel 24 forming the bottom surface of the wing 12. A pair of upper stringers 44 also extend through the additional rib 42 and connect the additional rib 24 to the skin panel 26 forming the top surface of the wing 12. However, as shown in FIG. Figure 3 As shown, the upper beam 44 has a smaller cross-sectional area and a smaller transverse width than the upper beam 36, and the upper beam 36 extends through Figure 2 The ribs 16 shown. Figure 2 Rib 16 and Figure 3 The upper stringers extending along the longitudinal length of the wing 12 transition from stringers 36 of larger cross-sectional area and larger transverse width to stringers 44 of smaller cross-sectional area and smaller transverse width between the additional ribs 42 .

[0034] In order to avoid using expensive titanium parts and related fasteners which would increase the weight of the wing 12 and increase the manufacturing time and cost of the wing 12, the Figure 2 The load between the upper stringers 36 of the ribs 16 is transmitted to the Figure 3The upper stringers 44 of the ribs 42 use the stringer transitions of the present disclosure that pass through a common base.

[0035] exist Figures 6 to 14 A method of constructing an aircraft structure having stringer transitions passing through a common base is illustrated in FIG. Figures 6 to 10 The aircraft structure or aircraft wing 12 is constructed using a conventional vacuum bagging process on an outer mold line (OML) layup mandrel 46 schematically illustrated in FIG.

[0036] refer to Figure 6 , a skin ply of composite material forming a skin panel 48 of the wing 12 is placed on a mandrel 46. The skin ply forming the skin panel 48 may be any combination of pre-impregnated fabrics and tapes that are required to provide the skin panel 48 with the required configuration to form the wing 12 and provide sufficient structural strength to the wing 12. The skin panel 48 has a longitudinal length extending between an inner edge 52 of the skin panel and an opposite outer edge 54 of the skin panel. The skin panel 48 has a transverse width extending between a forward edge 56 of the skin panel and an opposite rearward edge 58 of the skin panel. The skin plies forming the skin panel 48 are such that the skin panel has a thickness between an outer surface 62 of the skin panel and an opposite inner surface 64 of the skin panel. The outer surface 62 of the skin panel forms the outer surface of the wing 12 that is exposed to the external environment of the wing. The outer surface 62 of the skin panel 48 may be the top surface of the wing 12 or the bottom surface of the wing. An inner surface 64 of the skin panel 48 faces the interior of the wing 12 and forms a portion of the wing box 14 .

[0037] A base 66 composed of a ply of composite material is placed on the inner surface 64 of the skin panel 48, such as Figure 7 As shown. Figure 7 , the base 66 is shown as having an elongated, generally rectangular and generally planar configuration. However, the configuration of the base 66 may be varied to best accommodate the base 66 to the configuration of the wing 12 being constructed. The base 66 has an outer surface 68 and an opposite inner surface 72 that rests on the inner surface 64 of the skin panel 48. The inner surface 72 of the base 66 faces into the wing box 14 of the wing 12. The base 66 has a longitudinal length extending between an inner side edge 74 of the base and an opposite outer side edge 76 of the base. The longitudinal length of the base 66 is determined to provide the base 66 with sufficient longitudinal length to extend along the stringers used in the construction of the wing box 14 of the wing 12, as will be described. The longitudinal length of the base 66 may be the same longitudinal length as the skin panel 48. The base 66 has a transverse width extending between a forward edge 78 of the base and an opposite rearward edge 82 of the base. The transverse width of the base 66 is determined to be greater than the transverse width of the stringers used with the base 66, as will be described.

[0038] A first stringer 84, such as a cap stringer, composed of a composite material having a first cross-sectional area, a first transverse width, and a first cross-sectional configuration is placed on the inner surface 72 of the base 66. The first stringer 84 has an outer surface 86 and an opposite inner surface 88. The outer surface 86 of the first stringer 84 is placed on the inner surface 72 of the base 66. The inner surface 88 of the first stringer 84 faces the interior of the wing box 14 of the wing 12. The first stringer 84 has a longitudinal length extending between an inboard end 92 of the first stringer 84 and an opposite outboard end 94 of the first stringer. The first stringer 84 has a transverse width between a forward edge 96 of the first stringer and an opposite rearward edge 98 of the first stringer. As shown in FIG. Figure 8 As shown, the lateral width of the first beam 84 is slightly smaller than the lateral width of the base 66. Figure 8 As shown, the longitudinal length of the first beam 88 extends from an inboard end 92 of the first beam positioned substantially at the inboard edge 74 of the base 66. From the inboard end 92 of the first beam 84, the longitudinal length of the first beam 84 is aligned with and extends along a portion of the longitudinal length of the base 66.

[0039] Figure 8 Also shown is a second stringer 102 comprised of a composite material disposed on the base 66. The second stringer 102 has a second cross-sectional configuration, such as a blade stringer, and has a second cross-sectional area and a second transverse width that are less than the cross-sectional area and transverse width of the first stringer 84. Due to the decreasing interior area of ​​the wing box 14 as it extends from the inboard end 32 of the wing 12 toward the outboard end 34 of the wing 12, this reduction in the cross-sectional area and transverse width of the second stringer 102 enables the second stringer 102 to extend further along the longitudinal length of the wing box 14 than the first stringer 84 would otherwise extend. The second stringer 102 has an outer surface 104 and an opposing inner surface 106. The second stringer 102 also has a longitudinal length extending between an inboard end 108 of the second stringer 102 and an opposing outboard end 112 of the second stringer 102. The outer surface 104 of the second beam 102 is placed on the inner surface 72 of the base 66, wherein the longitudinal length of the second beam 102 is aligned with the longitudinal length of the first beam 84, and wherein the longitudinal length of the second beam 102 is aligned with and extends along a portion of the longitudinal length of the base 66. Figure 8 As shown, the inboard end 108 of the second beam 102 is opposite and longitudinally spaced from the outboard end 94 of the first beam 84. The second beam 102 also has a transverse width extending between a forward edge 114 of the second beam 102 and an opposite rearward edge 116 of the second beam 102. Figure 8 As shown, the lateral width of the second beam 102 between the forward edge 114 and the rearward edge 116 is slightly less than the lateral width of the base 66 between the forward edge 78 of the base 66 and the rearward edge 82 of the base 66 .

[0040] Prior to forming the skin panel 48, the base 66, the first stringer 84 and the second stringer 102 into a single unitary piece by vacuum bagging, runout cauls 122, 124 are positioned between the outboard end 94 of the first stringer 84 and the inboard end 108 of the second stringer 102 on the inner surface 72 of the base 66. Fig. 9 The backing plates 122, 124 transfer the pressure or force generated by the vacuum bag to the inner surface 72 of the base 66. Thus, the backing plates 122, 124 press the base 66 against the skin panel 48.

[0041] With the backing plates 122, 124 in place, a vacuum bag is positioned over the skin panel 48, the base 66, the first stringer 84 and the second stringer 102 and sealed to the layup mandrel 46. Air is evacuated between the vacuum bag and the mandrel 46 by a pump, causing the vacuum bag to be pulled down onto the first stringer 84, the second stringer 102 and the pair of backing plates 122, 124. This compresses the first stringer 84 and the second stringer 102 down onto the base 66 and the base 66 down onto the skin panel 48. The skin panel 48, the base 66, the first stringer 84 and the second stringer 102 are then cured in an autoclave, forming the skin panel 48, the base 66, the first stringer 84 and the second stringer 102 into a single integral fiber reinforced composite component. The vacuum bag is then removed from the layup mandrel 46, the backing plates 122, 124 are removed, and the integral skin panel 48, the base 66, the first stringer 84 and the second stringer 102 are removed.

[0042] After curing, portions of the outboard ends 94 of the first stringer 84 and the outboard ends 112 of the second stringer 102 may be trimmed. Figures 11 to 13 1. An example of a trimmed configuration of the outboard end 94 of the first stringer 84 and the inboard end 108 of the second stringer 102 is illustrated in FIG. The outboard end 94 of the first stringer 84 and the inboard end 108 of the second stringer 102 are trimmed to minimize loads at the opposite ends of the stringers that would cause ply delamination of the stringers.

[0043] After the skin panel 48, the base 66, the first stringer 84 and the second stringer 102 have been constructed together as a single unitary piece, the ribs may be attached to the skin panel 48 and the base 66. Fig.12 and Fig.13 As shown in Fig.12 and Fig.13As shown, the first rib 126 is mounted to the skin panel 48, the base 66, and the first stringer 84 by a first fastener 128. The second rib 132 is mounted to the skin panel 48, the base 66, and the second stringer 102 by a second fastener 134. The third rib 136 is mounted to the skin panel 48 and the base 66 between the first stringer 84 and the second stringer 102 by a third fastener 138. The base 66 extends below all of the ribs 126, 132, 136 and is common to both stringers 84, 102.

[0044] Although the stringer transitions through the common base 66 are described above as having only one base 66 extending along the longitudinal length of the skin panel 48 and one first stringer 84 extending along the longitudinal length of the base and one second stringer 102 extending along the longitudinal length of the base, it should be understood that the aircraft wing will likely be constructed with multiple pairs of stringers, each pair of stringers having a common base, wherein each pair of stringers and their common base extend longitudinally along the length of the aircraft wing, and wherein each pair of stringers and their common base are transversely spaced across the transverse width of the wing.

[0045] As various modifications may be made to the construction of the apparatus and its method of operation described and illustrated herein without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not limiting. Accordingly, the breadth and scope of the present disclosure shall not be limited by any of the above-described exemplary embodiments, but shall be defined only in accordance with the following claims appended hereto and their equivalents.

Claims

1. An aircraft structure, wherein: The aircraft structure comprises: a base having an outer surface and an opposed inner surface, the base having a longitudinal length between an inner side edge of the base and an opposed outer side edge of the base; a first stringer, the first stringer having an outer surface and an opposed inner surface, the first stringer having a longitudinal length between an inner end of the first stringer and an opposed outer end of the first stringer, the outer surface of the first stringer being secured to the inner surface of the base, the longitudinal length of the first stringer being aligned with and extending along the longitudinal length of the base; a second stringer, the second stringer having an outer surface and an opposed inner surface, the second stringer having a longitudinal length between an inner end of the second stringer and an opposed outer end of the second stringer, the outer surface of the second stringer being secured to the inner surface of the base, the longitudinal length of the second stringer being aligned with the longitudinal length of the first stringer, and the longitudinal length of the second stringer being aligned with and extending along the longitudinal length of the base; The first beam is longitudinally spaced from the second beam; and, The base connects the first stringer to the second stringer, and only the base connects the first stringer to the second stringer, wherein: the first beam has a cap beam cross-sectional configuration; and The second stringer has a blade stringer cross-sectional configuration.

2. The aircraft structure according to claim 1, further comprising: a skin panel having an outer surface and an opposed inner surface, the skin panel having a longitudinal length between an inner side edge of the skin panel and an opposed outer side edge of the skin panel, the skin panel having a transverse width between a forward side edge of the skin panel and an opposed rearward side edge of the skin panel; the base having a transverse width between a forward edge of the base and an opposite rearward edge of the base, the outer surface of the base being secured to the inner surface of the skin panel, the longitudinal length of the base being aligned with and extending along the longitudinal length of the skin panel; and, The transverse width of the base is smaller than the transverse width of the skin panel.

3. The aircraft structure according to claim 2, wherein: the first stringer having a transverse width between a forward edge of the first stringer and an opposite rearward edge of the first stringer; The second beam has a transverse width between a forward edge of the second beam and an opposite rearward edge of the second beam; and, The transverse width of the first beam is smaller than the transverse width of the base.

4. The aircraft structure according to claim 3, wherein: The transverse width of the second beam is smaller than the transverse width of the base.

5. The aircraft structure according to claim 1, further comprising: a first rib extending transversely through the first stringer; a second rib extending transversely across the second stringer; as well as, A single rib extends transversely between the first beam and the second beam.

6. The aircraft structure according to claim 5, further comprising: a first plurality of fasteners connecting the first rib to the base; a second plurality of fasteners connecting the second rib to the base; as well as, A third plurality of fasteners connects the single rib to the base.

7. The aircraft structure according to claim 2, wherein: The outer surface of the skin panel is the outer surface of an aircraft wing.

8. An aircraft structure, wherein: The aircraft structure comprises: a base constructed of a composite material, the base having an outer surface and an opposed inner surface, the base having a longitudinal length between an inner side edge of the base and an opposed outer side edge of the base; a first stringer constructed of a composite material, the first stringer having an outer surface and an opposite inner surface, the first stringer having a longitudinal length between an inner end of the first stringer and an opposite outer end of the first stringer, the outer surface of the first stringer being secured to the inner surface of the base, the longitudinal length of the first stringer being aligned with and extending along the longitudinal length of the base; a second stringer constructed of a composite material, the second stringer having an outer surface and an opposed inner surface, the second stringer having a longitudinal length between an inner end of the second stringer and an opposed outer end of the second stringer, the outer surface of the second stringer being secured to the inner surface of the base, the longitudinal length of the second stringer being aligned with the longitudinal length of the first stringer, and the longitudinal length of the second stringer being aligned with and extending along the longitudinal length of the base; the outboard end of the first stringer being longitudinally spaced from the inboard end of the second stringer; The base connects the outer surface of the first beam to the outer surface of the second beam, thereby connecting the first beam and the second beam; and, Only the base connects the first beam and the second beam, Wherein: the first beam has a cross-sectional configuration of a cap beam; and The second stringer has a cross-sectional configuration of a blade stringer.

9. An aircraft structure according to claim 8, wherein: the first stringer having a transverse width between a forward edge of the first stringer and an opposite rearward edge of the first stringer; The second beam has a transverse width between a forward edge of the second beam and an opposite rearward edge of the second beam; and, The transverse width of the first beam and the transverse width of the second beam are different.

10. The aircraft structure according to claim 8, further comprising: a skin panel constructed of a composite material, the skin panel having an outer surface and an opposed inner surface, the skin panel having a longitudinal length between an inner side edge of the skin panel and an opposed outer side edge of the skin panel, the skin panel having a transverse width between a forward side edge of the skin panel and an opposed rearward side edge of the skin panel; the base having a transverse width between a forward edge of the base and an opposite rearward edge of the base, the outer surface of the base being secured to the inner surface of the skin panel, the longitudinal length of the base being aligned with and extending along the longitudinal length of the skin panel; and The transverse width of the skin panel is greater than the transverse width of the base.

11. The aircraft structure according to claim 10, wherein: the first stringer having a transverse width between a forward edge of the first stringer and an opposite rearward edge of the first stringer; The second beam has a transverse width between a forward edge of the second beam and an opposite rearward edge of the second beam; and, The transverse width of the base is greater than the transverse width of the first beam.

12. The aircraft structure according to claim 11, wherein: The transverse width of the base is greater than the transverse width of the second beam.

13. The aircraft structure of claim 8, further comprising: a first rib extending transversely through the first beam and extending transversely through the base; a second rib extending transversely through the second beam and extending transversely through the base; as well as, A single rib extends transversely between the first beam and the second beam and extends transversely through the base.

14. The aircraft structure according to claim 13, further comprising: a first plurality of fasteners extending through the base and the first rib, the first plurality of fasteners connecting the first rib to the base; a second plurality of fasteners extending through the base and the second rib, the second plurality of fasteners connecting the second rib to the base; as well as, A third plurality of fasteners extend through the base and the single rib, the third plurality of fasteners connecting the single rib to the base.

15. The aircraft structure of claim 10, wherein: The outer surface of the skin panel is the outer surface of an aircraft wing.

16. A method of constructing an aircraft structure, wherein: The method comprises: Lower the base onto the outer mold line mandrel; lowering the cap beam onto said base; lowering a blade stringer onto the base, the blade stringer being aligned and spaced apart from the cap stringer; positioning a vacuum bag over the base, the cap stringer, and the blade stringer; curing the base, the cap stringer and the blade stringer in an autoclave; removing the vacuum bag from the base, the cap stringer, and the blade stringer; and, The ribs are mounted on the base.

17. The method according to claim 16, further comprising: before lowering the base onto the outer mold line mandrel, lowering a skin panel onto the outer mold line mandrel; Then, The base is lowered onto the skin panel.

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