Electroformed sheath

Abstract

An electroformed sheath for protecting an airfoil includes a sheath body and a mandrel insert is provided. The sheath body includes a leading edge. The sheath body includes a pressure side wall and an opposed suction side wall, which side walls meet at the leading edge and extend away from the leading edge to define a cavity between the side walls. The sheath body includes a head section between the leading edge and the cavity. The mandrel insert is positioned between the pressure side and suction side walls, and includes a generally wedge-shaped geometry. A method for protecting an airfoil includes: 1) securing a mandrel insert to a mandrel; 2) electroplating a sheath body onto the mandrel and the mandrel insert; 3) removing the mandrel from the sheath body so that a sheath cavity is defined within the sheath body; and 4) securing the airfoil within the sheath cavity.

What is claimed is: 
     
         1 . An electroformed sheath for protecting an airfoil of a gas turbine engine, comprising:
 a sheath body having a leading edge;   a pressure side wall and an opposed suction side wall of the sheath body, which side walls meet at the leading edge and extend away from the leading edge to define a cavity between the side walls;   a head section of the sheath body between the leading edge and the cavity; and   a mandrel insert positioned between the pressure side wall and suction side wall;   wherein the mandrel insert includes a cross-sectional geometry that is generally wedge-shaped.   
     
     
         2 . The electroformed sheath of  claim 1 , wherein the head section is defined by a length and a width, and wherein a ratio of the length to the width is related to the radius. 
     
     
         3 . The electroformed sheath of  claim 1 , wherein the mandrel insert is defined by a length and a width, and wherein the width of the mandrel insert is greater than a thickness of the sheath body pressure side wall or a thickness of the sheath body suction side wall. 
     
     
         4 . The electroformed sheath of  claim 1 , wherein the mandrel insert is made of a non-metallic composite. 
     
     
         5 . The electroformed sheath of  claim 4 , wherein the non-metallic composite includes one or more of the following materials: fiber-reinforced thermoset composite, fiber-reinforced thermoplastic composite, continuous or discontinuous carbon fiber or fiberglass fiber, bismaleimide, polyimide families, or thermoplastic matrix resins. 
     
     
         6 . The electroformed sheath of  claim 4 , wherein the mandrel insert is a honeycomb-like structure. 
     
     
         7 . The electroformed sheath of  claim 4 , wherein the mandrel insert is coated with a metallic material. 
     
     
         8 . The electroformed sheath of  claim 7 , wherein the metallic material includes one or more of the following materials: graphite, aluminum, silver or palladium. 
     
     
         9 . The electroformed sheath of  claim 1 , wherein a dimension of the mandrel insert is selected in order to achieve a dimension of the sheath body. 
     
     
         10 . The electroformed sheath of  claim 1 , wherein a geometry of the mandrel insert is selected in order to achieve a geometry of the sheath body. 
     
     
         11 . The electroformed sheath of  claim 1 , wherein sheath body is made of a material that is capable of being electroplated. 
     
     
         12 . The electroformed sheath of  claim 1 , wherein the sheath body is made of one or more of the following materials: nickel, nickel-cobalt alloy. 
     
     
         13 . A method for protecting an airfoil of a gas turbine engine, the method comprising the steps of:
 securing an electrically conductive mandrel insert to a mandrel, wherein the mandrel insert includes a cross-sectional geometry that is generally wedge-shaped;   electroplating, in an electroplate bath, a sheath body onto the mandrel and the mandrel insert;   removing the mandrel from the sheath body so that a sheath cavity is defined within the sheath body by the position occupied by the mandrel to form an electroformed sheath; and   securing the airfoil within the sheath cavity so that the electroformed sheath protects the airfoil.   
     
     
         14 . The method of  claim 13 , wherein the mandrel insert is made of a non-metallic composite. 
     
     
         15 . An airfoil of a gas turbine engine, comprising:
 a sheath body having a leading edge;   a pressure side wall and an opposed suction side wall of the sheath body, which side walls meet at the leading edge and extend away from the leading edge to define a cavity between the side walls;   a head section of the sheath body between the leading edge and the cavity; and   a mandrel insert positioned between the pressure side wall and suction side wall;   wherein the airfoil fills the cavity in affixing the electroformed sheath to the airfoil so that the leading edge, the head section and the mandrel insert protect the airfoil;   wherein the mandrel insert includes a cross-sectional geometry that is generally wedge-shaped.   
     
     
         16 . The airfoil of  claim 15 , wherein the airfoil is made of a first material and the mandrel insert is made of a second material, wherein the first material is less durable than the second material. 
     
     
         17 . The airfoil of  claim 16 , wherein the airfoil is one of the following: a fan blade, a turbine blade, or a compressor blade.