Abstract: Methods of making single piece multi-spar boxes made of composite material for aircraft are provided. Such methods include providing outer spars of the boxes which are made with a C-shaped cross-section such that the spars, during curing, are molded on the inside onto rigid, outer, lateral forming tools. As a result it is possible to obtain very precise outer profiles and positions of the spars.

Abstract: Methods of making single piece multi-spar boxes made of composite material for aircraft are provided. Such methods include providing outer spars of the boxes which are made with a C-shaped cross-section such that the spars, during curing, are moulded on the inside onto rigid, outer, lateral forming tools. As a result it is possible to obtain very precise outer profiles and positions of the spars.

Abstract: A beam of fiber-reinforced curable thermosetting composite material is preliminarily assembled in an uncured condition. The beam is placed between two forming tools, namely a lower and an upper tool, shaped in such a way as to give the lower and upper flanges a predetermined shape, at least one of the flanges having a non-rectilinear profile viewed in a longitudinal vertical plane. Two longitudinally elongate rigid inserts are placed between the flanges at the sides of the web and are covered in respective airtight tubular bags. The spaces between the upper tool and the lower tool on the two opposite longitudinal sides are sealed. The open opposite ends of the tubular bags are also sealed in such a manner that the pressure applied in an autoclave during the step of curing causes the tubular bags to swell and presses them against the two opposite faces of the web and against the flanges of the beam. On completion of curing, the upper forming tool is removed and the inserts are extracted sideways.

Abstract: For an arcuate structural member (10) of a fuselage frame, tapes of resin pre-impregnated unidirectional fibers are used. The member (10) includes a web (11) lying in a radial plane and a radially outer cylindrical flange (12). An elongate, arcuate forming mandrel (M1) having a flat radial surface (F) forming an angular edge (D) with a radially outer, convex cylindrical surface (S) is used and a series of promontories (P) radiating outwardly with respect to the cylindrical surface (S) are provided. Layers of pre-impregnated composite material are laid on the mandrel (M1) to form a first flat arcuate laminate (20?), with a part (20?) of the laminate projecting radially outwardly beyond the angular edge (D). The mandrel (M1), the laminate (20?) and the promontories (P) are covered with a membrane (E). A vacuum is then applied to urge the projecting part (20?) of the laminate against the cylindrical surface (S) and against the promontories (P).

Abstract: A beam of fibre-reinforced curable thermosetting composite material is preliminarily assembled in an uncured condition. The beam is placed between two forming tools, namely a lower and an upper tool, shaped in such a way as to give the lower and upper flanges a predetermined shape, at least one of the flanges having a non-rectilinear profile viewed in a longitudinal vertical plane. Two longitudinally elongate rigid inserts are placed between the flanges at the sides of the web and are covered in respective airtight tubular bags. The spaces between the upper tool and the lower tool on the two opposite longitudinal sides are sealed. The open opposite ends of the tubular bags are also sealed in such a manner that the pressure applied in an autoclave during the step of curing causes the tubular bags to swell and presses them against the two opposite faces of the web and against the flanges of the beam. On completion of curing, the upper forming tool is removed and the inserts are extracted sideways.

Abstract: For an arcuate structural member (10) of a fuselage frame, tapes of resin pre-impregnated unidirectional fibers are used. The member (10) includes a web (11) lying in a radial plane and a radially outer cylindrical flange (12). An elongate, arcuate forming mandrel (M1) having a flat radial surface (F) forming an angular edge (D) with a radially outer, convex cylindrical surface (S) is used and a series of promontories (P) radiating outwardly with respect to the cylindrical surface (S) are provided. Layers of pre-impregnated composite material are laid on the mandrel (M1) to form a first flat arcuate laminate (20?), with a part (20?) of the laminate projecting radially outwardly beyond the angular edge (D). The mandrel (M1), the laminate (20?) and the promontories (P) are covered with a membrane (E). A vacuum is then applied to urge the projecting part (20?) of the laminate against the cylindrical surface (S) and against the promontories (P).