Unducted fan for an aircraft turbine engine

1. An unducted fan for an aircraft turbine engine, comprising:

a propeller comprising a hub and an annular array of blades extending substantially radially outwards from said hub, the hub comprising an annular array of cowls, each of the cowls being mounted between radially inner ends of adjacent blades and suitable for being fixed to an upstream collar and to a downstream collar of the hub,

wherein at least one cowl comprises, at a circumferential end, at least one joint edge which is contiguous with a complementary joint edge of an adjacent cowl,

wherein said at least one cowl and at least one of said upstream and downstream collars are configured so that the at least one cowl can be mounted and dismounted by a movement including pivoting about an initial pivot axis which is circumferentially offset from said at least one joint edge towards a center of the at least one cowl, and so that, during said pivoting, said at least one joint edge moves radially inward from said complementary joint edge, and

wherein said initial pivot axis passes substantially through at least one pivot region of contact between the at least one cowl and at least one of the upstream collar and the downstream collar of the hub.

2. The unducted fan according to claim 1 , wherein each cowl comprises, at each of the circumferential ends thereof, a first joint edge on the upstream side and a second joint edge on the downstream side, said first and second joint edges being connected by a complementary concave curved edge of a plate supporting a blade.

3. The unducted fan according to claim 2 , wherein:

the first and second joint edges of each circumferential end of each cowl are aligned at least in part, or

the first and second joint edges of each circumferential end of each cowl extend at least in part in respectively two straight lines which are substantially parallel to each other and are separated circumferentially from each other.

4. The unducted fan according to claim 1 , wherein each joint edge has a straight shape which is substantially parallel to an axis of revolution of the propeller or has a shape having two contiguous straight-line segments, one of which is substantially parallel to said axis of revolution.

5. The unducted fan according to claim 2 , wherein the joint edges of one of the circumferential ends of each cowl each comprises a beveled end portion that joins said concave curved edge.

6. The unducted fan according to claim 1 , wherein each cowl comprises, at one of the circumferential ends thereof, a lug of reduced thickness terminating in said at least one joint edge and configured so as to be covered by a complementary lug of reduced thickness of the adjacent cowl, said lug comprising said complementary joint edge.

7. The unducted fan according to claim 6 , wherein the lug comprises screw mounting orifices for fixing the cowl to the adjacent cowl.

8. The unducted fan according to claim 1 , wherein each collar comprises a cylindrical rim for supporting and fixing a circumferential edge of each cowl, a pivot region for contact between the at least one cowl and at least one of said collars being formed on at least one of said cylindrical rims.

9. The unducted fan according to claim 8 , wherein:

the cylindrical rim of at least one of the collars comprises radial through notches which are configured so as to allow the pivoting of the cowls, or

at least one of the circumferential edges of each cowl comprises at least one radial through notch which is configured so as to allow pivoting of the cowl.

10. The unducted fan according to claim 9 , wherein at least one of said radial through notches creates an edge forming said pivot region for contact.

11. The unducted fan according to claim 1 , wherein the cowls are covered by radially inner ends of at least one of leading edges and trailing edges of at least one of the blades.

12. A method for removing a cowl of an unducted fan according to claim 1 , the method comprising:

a) from the two blades which are adjacent to the cowl, putting the blade which is furthest away from the initial pivot axis of the cowl in a position in which the radially inner end of the blade does not comprise any region covering a circumferential end of the cowl, while the blade which is closest to said pivot axis has at least one of a leading edge and a trailing edge having a radially inner end covering another circumferential end of the cowl,

b) pivoting the cowl about said initial pivot axis, so that the circumferential end of the cowl which is furthest away from said axis moves radially away from the hub, and

c) removing the cowl.

13. The method according to claim 12 , wherein step c) includes moving the cowl so that the center thereof circumferentially approaches the blade which is furthest away from the initial pivot axis, while pivoting the cowl about a pivot axis which is combined with or separate from the initial pivot axis.