Abstract: The present invention relates to a stringer, particularly to a stiffening and structural longitudinal element for skin of aircraft airfoil surfaces, characterized in that it incorporates two separate and independent reinforcement areas, one in the foot and the other at the end of the web (head) of the stringer, where the reinforcement areas are obtained by a widening of the section of the stringer, the widening being formed by a localized stack of reinforcing plies of composite material which are embedded within the stringer. The invention also relates to the method of manufacture and is particularly applicable to stringers having an L-shaped or T-shaped section.

Abstract: Method of manufacturing “T” shaped stringers (1) with an angle different from 90° between the web (2) and the foot (3) whereby the “T” shaped stringers have a stringer web and a stringer foot. The method comprises, after placing together two hot-formed “L” shaped semi-stringers to form a “T” shaped stringer, placing the “T” shaped stringer inside an invar alloy angle leaving a gap between the stringer web and the invar alloy angle. Afterwards, a heating device (7) is moved over the stringer feet (3) surface and a roller (8) slides over said stringer feet (3) surface to adapt the geometry of the stringer feet to the geometry of the invar alloy angle. The resulting “T” shaped stringer is co-bonded on a cured skin with an adhesive line between the stringer and the cured skin, and finally the obtained “T” shaped stringer is cured.

Abstract: The present invention relates to a stringer, particularly to a stiffening and structural longitudinal element for skin of aircraft airfoil surfaces, characterized in that it incorporates two separate and independent reinforcement areas, one in the foot and the other at the end of the web (head) of the stringer, where the reinforcement areas are obtained by a widening of the section of the stringer, the widening being formed by a localized stack of reinforcing plies of composite material which are embedded within the stringer. The invention also relates to the method of manufacture and is particularly applicable to stringers having an L-shaped or T-shaped section.

Abstract: Method of manufacturing “T” shaped stringers (1) with an angle different from 90° between the web (2) and the foot (3) whereby the “T” shaped stringers have a stringer web and a stringer foot. The method comprises, after placing together two hot-formed “L” shaped semi-stringers to form a “T” shaped stringer, placing the “T” shaped stringer inside an invar alloy angle leaving a gap between the stringer web and the invar alloy angle. Afterwards, a heating device (7) is moved over the stringer feet (3) surface and a roller (8) slides over said stringer feet (3) surface to adapt the geometry of the stringer feet to the geometry of the invar alloy angle. The resulting “T” shaped stringer is co-bonded on a cured skin with an adhesive line between the stringer and the cured skin, and finally the obtained “T” shaped stringer is cured.