Blade or vane with a root made by crossing weft yarns

A method for manufacturing a propeller blade or vane made of composite material comprising a fibrous reinforcement densified by a matrix, the method comprising:

• making a single-piece fibrous blank by three-dimensional weaving between a plurality of warp yarns and a plurality of weft yarns, the fibrous blank-having a flat shape in which the warp yarns extend along a longitudinal direction corresponding to the span direction of the propeller blade or vane to be manufactured and wherein the weft yarns extend along a transverse direction corresponding to the chord direction of the propeller blade or vane to be manufactured, the fibrous blank comprising an airfoil part and a root part intended to form respectively at least part of the fibrous reinforcement of the airfoil and of the root of the propeller blade or vane,
• shaping the fibrous blank to obtain a single-piece fibrous preform comprising an airfoil preform formed by the airfoil part of the fibrous blank and a root preform formed by the root part of the fibrous blank,
• densifying the fibrous preform by a matrix to obtain a propeller blade or vane made of composite material having a fibrous reinforcement constituted by the fibrous preform and densified by the matrix, and forming a single piece with an integrated root,
• wherein the root part of the fibrous blank comprises a first non-interlinking delimiting a first inner housing opening out at a free end of said root part and extending along the longitudinal direction, and wherein the root part includes at least one changing sub-area extending from the airfoil part and wherein a plurality of weft yarns located inside the root part of the fibrous blank cross on either side of the first non-interlinking along the transverse direction, the number of weft yarns crossing on either side of the first non-interlinking along the transverse direction in said changing sub-area increasing gradually from the airfoil part to the free end of the root part.