| CPC F01D 5/282 (2013.01) [B29C 70/24 (2013.01); B64C 11/26 (2013.01); F01D 5/30 (2013.01); B29L 2031/087 (2013.01); F05D 2230/23 (2013.01); F05D 2300/6034 (2013.01)] | 11 Claims |

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1. A method for manufacturing a propeller blade or airfoil for a turboprop engine made from composite material comprising a matrix-densified fibrous reinforcement, the method comprising:
producing a fibrous blank in a single piece by three-dimensional weaving, the fibrous blank having a flat shape extending in a longitudinal direction and a transverse direction respectively corresponding to the direction of its span between a lower portion and an upper portion and in the chord direction of the propeller blade or airfoil to be manufactured, the fibrous blank comprising a root portion and an aerodynamic profile portion extending in the longitudinal direction from the root portion and in the transverse direction between a leading-edge portion and a trailing-edge portion,
shaping the fibrous blank to obtain a single-piece fibrous preform having said aerodynamic profile portion forming an aerodynamic profile preform and said root portion forming a root preform, and
densification of the fibrous preform by a matrix to obtain an intermediate part made of composite material having a fibrous reinforcement constituted by the fibrous preform and densified by the matrix, the intermediate part comprising an aerodynamic profile portion and a root portion,
wherein the root portion of the fibrous blank comprises a separation delimiting an inner recess extending both into the root portion and into the aerodynamic profile portion of the fibrous blank, the separation extending in the transverse direction between the leading-edge and the trailing-edge of the fibrous blank and set back from said leading-edge and trailing-edge so as to preserve linking portions that are respectively adjacent to the leading-edge and the trailing-edge of the fibrous blank, the inner recess opening at the lower portion of the fibrous blank, wherein the shaping of the fibrous blank comprises the insertion of a spar in the inner recess, the spar comprising an aerodynamic profile shaping portion positioned in the aerodynamic profile portion of the fibrous blank and a root shaping portion positioned in the root portion of the fibrous blank in such a way as to respectively form an aerodynamic profile preform portion and a root preform portion, and, after the densification, machining the root portion of the intermediate part made of composite material along a determined radius in such a way as to form a propeller blade or airfoil comprising a root having a rotationally symmetric shape and an aerodynamic profile.
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