Fan blade composite cover with tapered edges
A fan blade for a turbofan gas turbine engine is disclosed. The fan blade includes a body having a pressure side and a suction side and a cover. The suction side of the body includes an opening exposing at least one cavity to reduce the weight of the fan blade. The cover overlays the opening and includes a leading portion and a trailing portion that are tapered in the direction of the cover leading edge and cover trailing edge.
1. A fan blade comprising:
a body having a pressure side, a suction side adjoining the pressure side along a fan blade leading edge and a fan blade trailing edge, the suction side defining an opening having a perimeter and communicating with one or more cavities disposed in the body; and
a cover configured to fit over the opening and comprising a cover leading edge and a cover trailing edge which generally align with the fan blade leading edge and the fan blade trailing edge respectively, the cover further comprising a central portion, a cover leading portion extending forward of the central portion and terminating at the cover leading edge, and a cover trailing portion extending aft of the central portion and terminating at the cover trailing edge;
wherein one or both of the cover leading portion and the cover trailing portion are chamfered; and
wherein at least one of the cover leading portion or the cover trailing portion comprises a flat chamfered surface.
2. The fan blade of claim 1 wherein: the leading portion is chamfered.
3. The fan blade of claim 1 wherein: the trailing portion is chamfered.
4. The fan blade of claim 1 wherein:
the leading portion is chamfered; and the trailing portion is chamfered.
5. The fan blade of claim 1 wherein:
the leading portion tapers in the direction of the cover leading edge; and the trailing portion tapers in the direction of the cover trailing edge.
6. The fan blade of claim 4 wherein:
the leading portion comprises a flat chamfered surface; and the trailing portion comprises a flat chamfered surface.
7. The fan blade of claim 4 wherein:
one of the leading portion or the trailing portion comprises a curved chamfered surface.
8. The fan blade of claim 4 wherein:
one of the leading portion or the trailing portion comprises a stepped chamfered surface.
9. The fan blade of claim 1 wherein:
the leading portion has substantially the same thickness as the central portion, then tapers to a smaller thickness at the cover leading edge; and
the trailing portion has substantially the same thickness as the central portion, then tapers to a smaller thickness at the cover trailing edge.
10. The fan blade of claim 2 wherein:
the area of minimal thickness of the fan blade body is located inward of the cover trailing edge.
11. The fan blade of claim 4 wherein:
the body comprises chamfered portions near the fan blade leading edge and the fan blade trailing edge; and
the body and the cover abut along their respective chamfered portions.
12. The fan blade of claim 1 wherein:
the opening communicates with one or more cavities disposed in the suction side of the body.
13. The fan blade of claim 1 wherein:
the opening communicates with one or more cavities disposed in the pressure side of the body.
14. The fan blade of claim 1 wherein:
the fan blade body is made of a denser material than the cover.
15. A fan blade cover configured to fit over an opening in a fan blade body, the cover comprising:
a cover leading edge;
a cover trailing edge downstream of the cover leading edge;
a central portion disposed between the cover leading edge and the cover trailing edge; a leading portion extending forward of the central portion and terminating at the cover leading edge; and
a trailing portion extending aft of the central portion and terminating at the cover trailing edge; wherein
one or both of the cover leading portion and the cover trailing portion are chamfered; and
wherein at least one of the cover leading portion or the cover trailing portion comprises a flat chamfered surface.
16. The fan blade cover of claim 14 wherein:
the leading portion has the same thickness as the central portion along an area adjoining the central portion and tapers to a smaller thickness at the cover leading edge.
17. The fan blade cover of claim 14 wherein:
the trailing portion has the same thickness as the central portion along the area adjoining the central portion and tapers to a smaller thickness at the cover trailing edge.
18. The fan blade cover of claim 14 wherein:
the opening communicates with one or more cavities disposed in a suction side of the fan blade body.
19. A method for fabricating a fan blade of a turbofan gas turbine engine comprising the steps of:
manufacturing a body including a pressure side and a suction side, the pressure side and the suction side being disposed between and connected to a leading edge and a trailing edge, the suction side defining an opening communicating with one or more cavities in the suction side;
providing a cover configured to fit over the opening and comprising a cover leading edge and a cover trailing edge, the cover further comprising a central portion, a chamfered leading portion extending forward of the central portion and terminating at the cover leading edge, and a chamfered trailing portion extending aft of the central portion and terminating at the cover trailing edge, at least one of the chamfered leading portion or the chamfered trailing portion comprises a flat chamfered surface; and
covering the opening with the cover.
20. The method of claim 14 wherein:
the cover leading portion tapers in the direction of the cover leading edge; and
the cover trailing portion tapers in the direction of the cover trailing edge.