Propulsion unit for an aircraft

A propulsion unit for an aircraft comprising:

• a bypass-type turbojet engine;
• a nacelle surrounding the turbojet engine, the nacelle comprising a downstream structure comprising an outer structure which defines, with a concentric inner structure surrounding a downstream compartment of the turbojet engine, an annular flow channel, the concentric inner structure being realized in a form of two annular half-portions;
• and
• means for displacing and for guiding at least one of the two annular half-portions, the displacing and guiding means being configured to displace and to guide said at least one of the two half-portion alternately between a working position wherein the two annular half-portions form a shell around the downstream compartment of the turbojet engine, and a maintenance position wherein said at least one annular half-portion uncovers at least partially the downstream compartment, the displacing and guiding means comprising at least one rail/slide system providing translational guiding of said at least one annular half-portion, alternately between an upstream and a downstream of the nacelle, and at least one connecting rod connected, on the one hand to said at least one annular half-portion and on the other hand to the turbojet engine, said at least one annular half-portion being pivotally mounted onto said at least one rail/slide system,
• wherein the rail/slide system is configured to radially move away with respect to a longitudinal axis of the nacelle at least an upstream upper portion of the at least one annular half-portion through which said half-portion is pivotably mounted on the rail/slide system, during a displacement of said at least one annular half-portion from the upstream toward the downstream of the nacelle, and
• wherein said connecting rod is configured to drive the at least one annular half-portion in rotation about an axis along which at least one guide rail of the rail/slide system extends, simultaneously with the displacement of the at least one annular half-portion along said guide rail.