Root pads for composite blades

Claim 1

A rotor assembly comprising the combination of: a disc having a plurality of substantially axially extending blade receiving slots circumferentially spaced around its periphery, each side of each of said slots including a flat, radially inwardly inclined centrifugal load bearing surface; a plurality of blades mounted in said slots, said blades comprising a plurality of plies compressed in a stack, said plies including high strength non-metallic filaments embedded in a matrix material, each blade including an airfoil and a splayed root, said airfoil including a substantially radial surface disposed adjacent and radially outwardly of said splayed root, said splayed root including a wedge shaped metallic insert, each side of said splayed root including a flat surface inclined radially inwardly; and a pad disposed on each side of said blade, each pad having a first surface and a second surface, said first surface mating with said blade in the area of transition between said airfoil and said root over a substantial portion of the blade root axial length, said first surface including a substantially radial portion which mates with said radial surface of said airfoil and a flat inclined portion which mates with said inclined surface of said root, said second surface being flat and mating with said centrifugal load bearing surface of said blade receiving slot, said second surface converging with respect to said inclined portion of said first surface in a direction away from said airfoil.