Composite fan blade leading edge sheath with encapsulating extension
AssigneeRtx Corporation
InventorsNicholas D. Stilin, Darin S. Lussier
Life of this patent
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Abstract
A metallic sheath for a composite fan blade includes a body comprising a leading edge portion configured to cover a leading edge of the blade; a top surface adjacent the leading edge; an extension portion proximate the top surface configured to cover a portion of a tip of the blade along an intermediate chord length; an encapsulation portion opposite the top surface configured to couple directly with the tip of the blade; a sheath suction side flank configured to overlap a suction side of the blade; a sheath pressure side flank opposite the suction side flank configured to overlap a pressure side of the blade; and an insulator coupled between the encapsulation portion and the tip of the blade.
Claims10
A metallic sheath assembly for a composite fan blade comprising:
- a metallic sheath comprising a body, said body comprising:
- a leading edge portion configured to cover a leading edge of the blade;
- a top surface adjacent the leading edge, at least one feature formed on said top surface, said at least one feature configured to abrade a fan casing liner;
- an extension portion proximate the top surface configured to cover a portion of a tip of the blade along an intermediate chord length;
- an encapsulation portion opposite said top surface configured to couple directly with the tip of the blade;
- a sheath suction side flank configured to overlap a suction side of the blade;
- a sheath pressure side flank opposite said suction side flank configured to overlap a pressure side of the blade;
- and
- an insulator coupled between the encapsulation portion and the tip of the blade;
- a tip cap coupled to said metallic sheath and the tip of the blade and an aft portion of the blade wherein the tip cap comprises a truncated section structured for the leading edge sheath extension portion to extend over the truncated section;
- a joint formed between said metallic sheath and said tip cap, the joint comprising a finger joint;
- and
- an adhesive reserve between the metallic sheath and the composite fan blade, wherein the sheath suction side flank and the sheath pressure side flank extend along the blade and permit the adhesive reserve between the metallic sheath and the composite fan blade to react to a sheath centrifugal load in shear in the absence of tension.
A process for limiting a temperature of a composite fan blade responsive to a rub event between the composite fan blade and a fan casing liner comprising:
- coupling a metallic sheath to the composite fan blade, said metallic sheath comprising a body, said body comprising:
- a leading edge portion configured to cover a leading edge of the composite fan blade;
- a top surface adjacent the leading edge;
- an extension portion proximate the top surface configured to cover a portion of a tip of the composite fan blade along an intermediate chord length;
- an encapsulation portion opposite said top surface configured to couple directly with the tip of the composite fan blade;
- a sheath suction side flank configured to overlap a suction side of the composite fan blade;
- a sheath pressure side flank opposite said suction side flank configured to overlap a pressure side of the composite fan blade;
- and
- an insulator coupled between the encapsulation portion and the tip of the composite fan blade;
- coupling a tip cap to said metallic sheath, wherein the tip cap comprises a truncated section structured for the leading edge sheath extension portion to extend over the truncated section;
- coupling the tip cap to the tip of the composite fan blade and to an aft portion of the composite fan blade;
- and
- forming a joint between said metallic sheath and said tip cap, the joint comprising a finger joint;
- and
- coupling an adhesive reserve between the metallic sheath and the composite fan blade, the adhesive reserve configured to accommodate a degradation of a bond between the metallic sheath and the composite fan blade, wherein a length of the sheath suction side flank and the sheath pressure side flank that adhere the leading edge sheath to the composite fan blade are configured such that a peak adhesive shear stress in the adhesive, due to operational and impact loads, is within a strength allowable for the adhesive.
Dependencies are inferred from the claim text.