Method of making composite airfoil structures

• US 6,689,246 B2
• Filed: 04/04/2001
• Issued: 02/10/2004
• Est. Priority Date: 07/30/1998
• Status: Expired due to Fees

• Current Assignee: Japan Aircraft Development Corporation
• Original Assignee: Japan Aircraft Development Corporation
• Inventors: Hirahara, Makoto, Amaoka, Kazuaki, Shimizu, Ryuhei, Isano, Yasuo
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): WARD, JESSICA LEE
• Application Number:
  US09/824,678
• Publication Number:
  US 20010017336A1
• Time in Patent Office: 1,042 Days
• Field of Search: 156/242, 156/292, 156/297, 156/300, 156/302, 156/245, 244/123-126, 264/239, 264/250, 264/257, 264/258, 264/263
• US Class Current: 156/292
• CPC Class Codes: B64C 3/18 Spars; Ribs; Stringers
• CPC Class Codes: B64C 3/20 Integral or sandwich constructions
• CPC Class Codes: B64C 3/26 Construction, shape, or attachment of separate skins, e.g. panels

Abstract

A box-structure airfoil is constructed of a composite material uppers skin, a composite material lower a skin 12 and a spar. Ribs and an elongate projection are formed integrally on the inner surface of each of the two skins. The upper and lower skins and the spar are simultaneously bonded by an adhesive to form a single structure. Since the ribs and the elongate projection are one-piece formed with each skin, it is possible to reduce the number of principal constituent components. Furthermore, since assembly operation is made by using the adhesive, there is no need for fasteners or the like for assembling. Moreover, the flanges on both sides of the spar can also be bonded to the respective skins. According to the invention, it is possible to reduce the number of principal constituent components and that of assembling components of an airfoil, thereby achieving its cost reduction.

Claims

1. A method of forming a composite material airfoil structure, comprising:

a molding process in which a first composite material skin, which forms one surface of an airfoil, and a second composite material skins which has ribs and an elongate projection integrally formed on an inner surface and forms the other surface of said airfoil, are separately formed; and

a bonding process in which bonding between extreme ends of said ribs and elongate projection and said first skin, bonding between individual flanges of a spar and said first and second skins, and bonding between a web of said spar and said elongate projection are simultaneously done using an adhesive to thereby form a single structure.

2. A method of forming a composite material airfoil structure as according to claim 1, wherein said first skin is formed by

laminating composite material prepreg on a mold base having the same outer contours as said airfoil,

placing a foam core covered with a glue film on an upper surface of the prepreg,

laminating again composite material prepreg on top, and

hardening an entire assembly by a thermosetting operation.

3. A method of forming a composite material airfoil structure according to claim 1, wherein a pasty thermosetting adhesive is used as said adhesive.

4. A method of forming a composite material airfoil structure according to claim 1, wherein said second skin is formed by

laminating composite material prepreg on a mold base having the same outer contours as said airfoil,

depositing layers of a foam core covered with a glue film, composite material prepreg, an intra-projection foam core covered with a glue film, composite material prepreg, intra-rib foam cores covered with a glue film, and composite material prepreg, one on top of another, in this order, and

hardening an entire assembly by a thermosetting operation.

5. A method of forming a composite material airfoil structure according to claim 4, wherein pressure plates are placed at least on end surfaces of said ribs and elongate projection prior to the thermosetting operation,

said pressure plates having shapes corresponding to the shapes of mating bond surfaces.

6. A method of forming a composite material airfoil structure, comprising:

a molding process in which a first composite material skins which has ribs and an elongate projection integrally formed on an inner surface, forms one surface of an airfoil and a second composite material skin, which has ribs and an elongate projection integrally formed on an inner surface and forms the other surface of said airfoil, are separately formed; and

a bonding process in which bonding between extreme ends of said ribs and elongate projections of said first and second skins, bonding between individual flanges of a spar and said first and second skins, and bonding between a web of said spar and said elongate projections are simultaneously done using an adhesive to thereby form a single structure.

7. A method of forming a composite material airfoil structure according to claim 6, wherein a pasty thermosetting adhesive is used as said adhesive.

8. A method of forming a composite material airfoil structure according to claim 6, wherein each said first and second skins is formed by

laminating composite material prepreg on a mold base having the same outer contours as said airfoil,

laminating layers of a foam core covered with a glue film, composite material prepreg, an intra-projection foam core covered with a glue film, composite material prepreg, intra-rib foam cores covered with a glue film, and composite material prepreg, one on top of another, in this order, and

hardening an entire assembly by a thermosetting operation.

9. A method of forming a composite material airfoil structure according to claim 8, wherein pressure plates are placed at least on end surfaces of said ribs and elongate projections prior to the thermosetting operation,

said pressure plates having shapes corresponding to the shapes of mating bond surfaces.