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.

Abstract: A box-structure airfoil is constructed of a composite material upper skin, a composite material lower 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 spar is bonded not only to Moreover, because not only a web but also flanges on both sides of the spar are bonded to the respective skins, it is possible to obtain a large strength. 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.

Abstract: A box-structure airfoil is constructed of a composite material upper skin, a composite material lower 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 spar is bonded not only to Moreover, because not only a web but also flanges on both sides of the spar are bonded to the respective skins, it is possible to obtain a large strength. 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.

Abstract: A rib of a composite material for a box structure such as an airfoil has, in an integral structure, a web and flanges formed so as to extend along opposite longitudinal side edges of the web. The web is provided with a plurality of parallel first ridges or beads formed so as to extend across the web and to protrude outward from the outer surface of the web, and each of the flanges is provided with a plurality of parallel second ridges formed so as to extend across the flange, to protrude inward from the outer surface thereof and to merge into the corresponding first ridges. The structure eliminates causes of wrinkles and provides an increased strength.