Method for manufacturing a propeller blade

1. A method for manufacturing a blade made of composite material extending in a main elongation direction, said blade comprising a root, a trailing edge and at least one internal airflow channel, the composite material of said blade comprising a fiber reinforcement densified by a matrix, the method comprising the following steps:

a step of weaving a plurality of warp yarns and a plurality of weft yarns so as to obtain a fiber preform, the fiber preform comprising at least one warp yarn adapted over at least one portion of its length to form in the matrix at least one first portion of a channel, said portion of length of the warp yarn being directed according to the main elongation direction of the blade and emerging from the root of the blade, the first channel portion formed in the matrix by said portion of length of warp yarn constituting at least one first portion of the internal airflow channel;

a densification step of the blade preform by impregnation of said blade preform by material constituting the matrix;

wherein the weaving step also comprises placing at least one second portion of yarn adapted to form in the matrix a second portion of a channel, said second portion of yarn being transversally directed relative to said main elongation direction (α) and emerging from the trailing edge of the blade, said second portion of yarn being in contact with the portion of length of warp yarn and being a weft yarn which extends from a leading edge of the blade to the trailing edge, said weft yarn crossing with contact the portion of length of the warp yarn adapted to form a first channel portion such that the first and the second portions of the internal airflow channel open in each other by way of contact between said yarns, allowing circulation of an airflow from the root to the trailing edge.

2. The method according to claim 1 , wherein the warp yarn adapted to form at least one first portion of a channel, and the second portion of yarn adapted to form a second portion of a channel are hollow fibers.

3. The method according to claim 1 , wherein the warp yarn adapted over at least one portion of its length to form in the matrix at least one first portion of a channel, and the second portion of yarn adapted to form in the matrix a second portion of a channel are fugitive fibers, said method comprising an elimination step by thermal or chemical treatment.

4. The method according to claim 1 , further comprising a blocking step of the second portion of the internal airflow channel on the leading edge side.

5. The method according to claim 4 , wherein the blocking step is conducted by laying an antierosion polyurethane film, or laying a de-icing heating mat at the leading edge, or by injection of resin, or by injection of resin followed by laying a de-icing heating mat at the leading edge.

6. A method for manufacturing a blade made of composite material extending in a main elongation direction, said blade comprising a root, a trailing edge and at least one internal airflow channel, the composite material of said blade comprising a fiber reinforcement densified by a matrix, the method comprising the following steps:

a step of weaving a plurality of warp yarns and a plurality of weft yarns so as to obtain a fiber preform, the fiber preform comprising at least one warp yarn adapted over at least one portion of its length to form in the matrix at least one first portion of a channel, said portion of length of the warp yarn being directed according to the main elongation direction of the blade and emerging from the root of the blade, the first channel portion formed in the matrix by said portion of length of warp yarn constituting at least one first portion of the internal airflow channel;

a densification step of the blade preform by impregnation of said blade preform by material constituting the matrix;

wherein the weaving step also comprises placing at least one second portion of yarn adapted to form in the matrix a second portion of a channel, said second portion of yarn being transversally directed relative to said main elongation direction (α) and emerging from the trailing edge of the blade, said second portion of yarn being in contact with the portion of length of warp yarn, the warp yarn being adapted over at least one portion of its length to form in the matrix at least one first portion of a channel comprises a non-woven free end which is folded towards the trailing edge transversally relative to the main elongation direction of the blade, said free end being intended to form the second portion of the internal airflow channel transversally directed relative to said main elongation direction.

7. The method according to claim 6 , characterized in that the free end is woven with the warp yarns.

8. The method according to claim 6 , characterized in that the free end is deposited on the surface of the fiber reinforcement without being woven.

9. The method according to claim 1 , characterized in that a warp yarn intended to form a channel directed according to the main elongation direction, extends from the root to a tip of the blade so as to form a first portion of the internal airflow channel which opens at said tip of the blade.