Monobloc flameholder arm for an afterburner device of a bypass turbojet

1. A support arm for an afterburner device of a bypass turbojet, said device comprising first and second inner annular casings defining a passage for a primary flow and an outer annular casing defining together with said first inner annular casing a passage for a secondary flow, said support arm comprising:

a monobloc structure made of composite material including two integral walls designed to define a groove having a substantially V-shaped profile and including first end parts joined together and adapted to define a foot and second end parts adapted each to define at least one flange which can be positively connected to the said outer casing,

wherein the thickness of said walls is not constant between said first and second end parts.

2. The arm according to claim 1 , wherein the spacing of said walls is not constant between said first and second end parts, such that the profile of said groove varies.

3. The arm according to claim 2 , wherein said spacing varies substantially continuously, increasing from the first end parts to the second end parts, such that the profile of said groove varies substantially continuously.

4. The arm according to claim 1 , wherein the thickness of said walls is greater at said second end parts.

5. The arm according to claim 1 , wherein said walls each include a notch at the same selected level so as to define a housing which can receive a burner ring support.

6. The arm according to claim 5 , wherein said burner ring support is positively connected to said walls in the vicinity of said notches.

7. The arm according to claim 5 , wherein said burner ring support is positively connected to said walls with rivets.

8. The arm according to claim 5 , wherein said notches are formed in a zone of a part of said walls intended to be placed in the passage for the secondary flow.

9. The arm according to claim 8 , wherein said zone is intended to be placed in the vicinity of said first inner casing.

10. The arm according to claim 1 , wherein each flange can be positively connected to said outer casing with at least one bolt, with the interposition of a backing plate on the side of the flange exposed to said secondary flow.

11. The arm according to claim 1 , wherein said monobloc structure is made of a composite material having a ceramic matrix.

12. An afterburner device for a bypass turbojet, comprising:

first and second inner annular casings defining a passage for a primary flow and an outer annular casing defining together with said first inner annular casing a passage for a secondary flow,

at least three support arms, each according to claim 1 positively connected to said outer annular casing.

13. The device according to claim 12 , further comprising, in the passage for said secondary flow, an insulating liner defining together with said outer annular casing an afterburner jet pipe for part of said secondary flow, and

wherein said burner support ring of each support arm is placed at a level between the level of said insulating liner and the level of said first inner annular casing.

14. A turbojet comprising a support arm according to claim 1 .

15. A turbojet comprising a support arm according to claim 2 .

16. A turbojet comprising a support arm according to claim 3 .

17. A turbojet comprising a support arm according to claim 4 .

18. A turbojet comprising a support arm according to claim 5 .

19. A turbojet comprising a support arm according to claim 6 .