A method for manufacturing a box-shaped structure for a horizontal stabilizer for aircrafts using a fiber-reinforced polymer matrix prepreg composite material, said structure extending along a longitudinal direction between a first longitudinal end and a second longitudinal end, and comprising:
- a first longitudinal wall;
- a second longitudinal wall facing the first wall and arranged spaced from the first wall itself by a non-zero amount;
- a plurality of spars extending longitudinally and between said first wall and second wall, connected to these latter and delimiting with the first wall and the second wall respective longitudinal cavities;
- and
- at least one reinforcing rib arranged transversal to the spars at a transversal sector of said box-shaped structure interposed between said first longitudinal end and second longitudinal end;
- the method comprising the steps of:
- a) laminating a first plurality of layers of said prepreg composite material on a first forming plate of a forming mold, so as to form a first skin of composite material defining said first wall;
- b) laminating a second plurality of layers of said prepreg composite material on a second forming plate of said forming mold, so as to form a second skin of composite material defining said second wall;
- c) arranging a plurality of elongated support tools each having a central axis and a cross section with a polygonal external profile complementary to the profile of the longitudinal cavities to be formed in said structure;
- d) laminating a third plurality of layers of said prepreg composite material on three contiguous walls of each support tool, so as to obtain elongated profiles made of said composite material, each profile having a longitudinal axis and a C-shaped cross section, and comprising a central flange and two winglets projecting transversally from the flange;
- e) joining said profiles two by two along the respective flanges adjoining side by side respective pairs of support tools so that the profiles themselves have opposite concavities, so as to obtain respective spars having a double-T cross section defined by a central web and two opposite end wings;
- f) longitudinally arranging the adjoined support tools and the spars previously obtained on the first wall previously obtained in such a way that respective first wings of the spars are coplanar in contact with said first wall and in such a way that the webs of the spars are oriented along said longitudinal direction;
- g) arranging said second wall on the assembly obtained in step f), in such a way that the second wall is coplanar in contact with respective second wings of the spars opposite said first wings, thus delimiting said longitudinal cavities and thus defining a first assembly of the box-shaped structure including the first wall, the second wall and the spars;
- wherein the step d) of laminating the third plurality of layers comprises, for each profile:
- d1) laminating the relative winglets, from one axial end of the profile to the other axial end of the profile;
- d2) laminating a first portion of said flange from said one axial end up to a predetermined axial coordinate of the profile, interposed between said axial ends along the longitudinal axis of the profile itself, said first portion being substantially full in the longitudinal direction and in the transversal direction to the relative longitudinal axis and between the relative fins;
- d3) laminating a second portion of said flange from said axial coordinate to said other axial end, said second portion having a through slot extending longitudinally from the axial coordinate up to said other axial end and laterally open at said other axial end by means of a relative lateral opening, so as to define a lack or void of material on the relative flange in the longitudinal direction, so that each spar obtained by means of the step e) of joining has, in turn, on the respective web, a longitudinal spar cavity open laterally and determined by the union of the relative slots;
- wherein the step f) of arranging comprises:
- f1) orienting the spars in such a way that the relative spar cavities all face one another transversally to the longitudinal direction of the box-shaped structure and are all arranged at said first longitudinal end of the box-shaped structure;
- f2) orienting the spars in such a way that the lateral openings of the slots (19) are arranged at said first longitudinal end (la);
- and wherein the method further comprises the steps of:
- h) after the step g) of arranging, inserting said reinforcing rib into said first assembly starting from said first longitudinal end and through the lateral openings of the slots, so as to engage the spar cavities;
- i) advancing the reinforcing rib, previously inserted in the first assembly, inside the spar cavities in the longitudinal direction towards said second longitudinal end and up to said transversal sector.