Protector for a leading edge of an airfoil

Abstract

A protector for the leading edge of a rotor blade to provide enhanced erosion protection thereof. In an embodiment, the protector includes an energy absorption member attached to the rotor blade by a first adhesive bond layer and an erosion resistant member attached to the energy absorption member by a second adhesive bond layer. The erosion resistant member is operative to protect the leading edge of the rotor blade from erosion due to impacts from particulate matter, such as sand and rain. The energy absorption member is operative to absorb and disburse energy from impacts to the erosion protection member so that forces from the impacts are diminished or not transferred to the rotor blade. In another embodiment, the erosion resistant member is coated with a diamond film. As the diamond film is harder than sand, excellent resistance to wear from particulate matter and impacts rain is obtained. Other advantages provided by use of the diamond film include: 1) an ultra-smooth surface that reduces drag on the rotor blade whereby flight performance may be improved, and 2) by being ultra-smooth and chemically inert de-icing equipment may not be needed.

1 . A protector for an airfoil, comprising:
 an energy absorption member;   a first adhesive bond layer attached to said energy absorption member wherein said first adhesive bond layer is adapted for attaching said protector to a leading edge of said airfoil and having a bonding strength between said energy absorption member and said airfoil such that said protector is manually removable from said leading edge;   an erosion resistant member forming the outer surface of said protector and providing erosion resistance against environmental effects, wherein said erosion resistant member is made of a metal or alloy;   a second adhesive bond layer sandwiched between said energy absorption member and said erosion resistant member, wherein said adhesive bond layer bonds said erosion resistant member to said energy absorption member;   wherein environmental impact forces against said erosion resistant member are at least partially dissipated by said energy absorption member prior to being transferred to said airfoil; and   wherein said protector has a flexibility whereby it can be manually pressed against said leading edge and conformed to a contour of said leading edge.   
   
   
       2 . The protector in accordance with  claim 1 , wherein said airfoil is a helicopter rotor blade. 
   
   
       3 . The protector in accordance with  claim 1  wherein said protector generally forms a C-shape when applied to said leading edge. 
   
   
       4 . The protector in accordance with  claim 1  wherein said energy absorption member is not exposed to the environment when applied to said leading edge. 
   
   
       5 . The protector in accordance with  claim 1  wherein said energy absorption member covers trailing edges of said energy absorption member and extends to said airfoil. 
   
   
       6 . The protector in accordance with  claim 1  wherein said second adhesive bond layer has a bonding strength between said energy absorption member and said erosion resistant which is greater than said bonding strength between said rotor blade and said energy absorption member. 
   
   
       7 . The protector in accordance with  claim 6  wherein said second adhesive bond layer is formed of a permanent adhesive. 
   
   
       8 . The protector in accordance with  claim 6  wherein said first adhesive bond layer is a double-coated polyester substrate film. 
   
   
       9 . A airfoil having a protector, comprising:
 a rotor blade having a leading edge;   an energy absorption member;   a first adhesive bond layer attaching said energy absorption member to said leading edge and having a bonding strength between said energy absorption member and said airfoil such that said protector is manually removable from said leading edge;   an erosion resistant member forming the outer surface of said protector and providing erosion resistance against environmental effects, wherein said erosion resistant member is made of a metal or alloy;   a second adhesive bond layer sandwiched between said energy absorption member and said erosion resistant member, wherein said adhesive bond layer bonds said erosion resistant member to said energy absorption member;   wherein environmental impact forces against said erosion resistant member are at least partially dissipated by said energy absorption member prior to being transferred to said airfoil; and   wherein said protector has a flexibility whereby it can be manually pressed against said leading edge and conformed to a contour of said leading edge.   
   
   
       10 . The protector in accordance with  claim 9  wherein said protector generally forms a C-shape when applied to said leading edge. 
   
   
       11 . The protector in accordance with  claim 9  wherein said energy absorption member is not exposed to the environment when applied to said leading edge. 
   
   
       12 . The protector in accordance with  claim 9  wherein said energy absorption member covers trailing edges of said energy absorption member and extends to said airfoil. 
   
   
       13 . The protector in accordance with  claim 9  wherein said second adhesive bond layer has a bonding strength between said energy absorption member and said erosion resistant which is greater than said bonding strength between said rotor blade and said energy absorption member. 
   
   
       14 . A protector for an airfoil, comprising:
 an energy absorption member;   a first adhesive bond layer attached to said energy absorption member wherein said first adhesive bond layer is adapted for attaching said protector to a leading edge of said airfoil and having a bonding strength between said energy absorption member and said airfoil such that said protector is manually removable from said leading edge;   an erosion resistant member forming the outer surface of said protector and providing erosion resistance against environmental effects, wherein said erosion resistant member is made of a metal or alloy;   a second adhesive bond layer sandwiched between said energy absorption member and said erosion resistant member, wherein said adhesive bond layer bonds said erosion resistant member to said energy absorption member;   a diamond film layer attached to a major surface of said erosion resistant member;   wherein environmental impact forces against said diamond film are at least partially dissipated by said energy absorption member prior to being transferred to said airfoil; and   wherein said protector has a flexibility whereby it can be manually pressed against said leading edge and conformed to a contour of said leading edge.   
   
   
       15 . The protector in accordance with  claim 14  wherein said diamond film layer has a hardness of at least 18 GPa. 
   
   
       16 . The protector in accordance with  claim 14  wherein said diamond film layer has a hardness of between 18 GPa and 90 GPa. 
   
   
       17 . The protector in accordance with  claim 14  wherein said diamond film layer has an average root mean square surface roughness of less than 5.00 nm. 
   
   
       18 . The protector in accordance with  claim 14  wherein said diamond film layer has an average root mean square surface roughness of less than 2.00 nm. 
   
   
       19 . The protector in accordance with  claim 14  wherein said diamond film layer has a thickness has a thickness of 40 mils or less. 
   
   
       20 . The protector in accordance with  claim 14  wherein said diamond film layer has a thickness has a thickness within the range of 0.5 mils and 20 mils.