Aerofoil, an aerofoil sub-assembly and a method of making the same

Abstract

An aerofoil sub-assembly of a blade, in particular an aerofoil blade for a gas turbine engine. A multi-layer construction including first and second skin panels which together define the external surfaces of the aerofoil and aerofoil leading and trailing edges. Between the skin panels at least there is at least one web-forming membrane which has a multiplicity of fingers trapped between the first and second panels at one of the edges and which extend away from the edge region. The fingers each have “dog-leg” shapes which are overlaid immediately behind the blade leading edge to form a transition zone providing additional support to resist crumpling of the hollow blade in the event of an external foreign object striking the leading edge.

1 . An aerofoil sub-assembly of multi-layer construction comprising first and second skin panels which together define the external surfaces of the aerofoil and aerofoil leading and trailing edges, and lying between the skin panels two or more web-forming membranes which comprise a multiplicity of fingers trapped between the first and second panels at one of the edges and which extend away from the edge region, wherein each web-forming membrane comprises a comb-like structure in which the multiplicity of fingers project from a spine portion at a panel edge, wherein the fingers of the web-forming membranes extend from a spine portion and have a proximal portion and a distal portion angled thereto in the shape of a dog-leg. 
     
     
         2 . An aerofoil sub-assembly of multi-layer construction comprising first and second skin panels which together define the external surfaces of the aerofoil and aerofoil leading and trailing edges, and lying between the skin panels two or more web-forming membranes which comprise a multiplicity of fingers trapped between the first and second panels at one of the edges and which extend away from the edge region. 
     
     
         3 . An aerofoil sub-assembly according to  claim 2 , comprising first and second web-forming membranes wherein each web-forming membrane comprises a comb-like structure in which the multiplicity of fingers project from a spine portion at a panel edge. 
     
     
         4 . An aerofoil sub-assembly according to  claim 1 , wherein part of the first web-forming membrane is bonded to part of the first panel and part of the second web-forming membrane is bonded to part of the second panel. 
     
     
         5 . An aerofoil sub-assembly according to  claim 4  in which the fingers of the first and second membranes are overlaid. 
     
     
         6 . An aerofoil sub-assembly according to  claim 3 , wherein the fingers of the web-forming membranes extend from a spine portion and have a proximal portion and a distal portion angled thereto in the shape of a dog-leg. 
     
     
         7 . An aerofoil sub-assembly according to  claim 1 , wherein the proximal portions of the fingers of a web-forming membrane subtend an oblique angle relative to the spine of the web. 
     
     
         8 . An aerofoil sub-assembly according to  claim 1 , wherein the proximal portions of the fingers of the first and second web-forming members are angled in opposite directions. 
     
     
         9 . An aerofoil sub-assembly according to  claim 1 , wherein the distal portion of the fingers lie in a direction perpendicular to the spine of the web-forming membrane. 
     
     
         10 . An aerofoil sub-assembly according to  claim 1 , wherein the web-forming membranes are assembled such that the distal portions of the fingers of one membrane overlap those of the other membrane and are diffusion bonded together and to a skin panel. 
     
     
         11 . An aerofoil sub-assembly according to  claim 10 , wherein alternate fingers are bonded to opposite skin panels. 
     
     
         12 . An aerofoil sub-assembly according to  claim 1 , wherein the distal portion comprises a first distal portion immediately adjoining the proximal portion and a second distal portion comprising one or more further dog-legs. 
     
     
         13 . An aerofoil sub-assembly of multi-layer construction comprising first and second skin panels which together define the external surfaces of the aerofoil and aerofoil leading and trailing edges, and lying between the skin panels two or more web-forming membranes which comprise a multiplicity of fingers trapped between the first and second panels at one of the edges and which extend away from the edge region, wherein each web-forming membrane comprises a comb-like structure in which the multiplicity of fingers project from a spine portion at a panel edge, wherein the fingers of the web-forming membranes subtend an oblique angle relative to the spine of the web. 
     
     
         14 . An aerofoil sub-assembly according to  claim 2 , wherein part of the first web-forming membrane is bonded to part of the first panel and part of the second web-forming membrane is bonded to part of the second panel. 
     
     
         15 . An aerofoil sub-assembly according to  claim 6 , wherein the proximal portions of the fingers of a web-forming membrane subtend an oblique angle relative to the spine of the web. 
     
     
         16 . An aerofoil sub-assembly according to  claim 6 , wherein the proximal portions of the fingers of the first and second web-forming members are angled in opposite directions. 
     
     
         17 . An aerofoil sub-assembly according to  claim 6 , wherein the distal portion of the fingers lie in a direction perpendicular to the spine of the web-forming membrane. 
     
     
         18 . An aerofoil sub-assembly according to  claim 6 , wherein the web-forming membranes are assembled such that the distal portions of the fingers of one membrane overlap those of the other membrane and are diffusion bonded together and to a skin panel. 
     
     
         19 . An aerofoil sub-assembly according to  claim 6 , wherein the distal portion comprises a first distal portion immediately adjoining the proximal portion and a second distal portion comprising one or more further dog-legs.