Rotor blade and structural system for coupling the rotor blade in a rotor hub

Abstract

The rotor hub can include a rotor blade; a rotor yoke; a grip member having an inboard portion, an upper extension, and a lower extension; and a rotor blade having a root end coupled to the upper extension and the lower extension of the grip member with a first bolt, a second bolt, and a third bolt. The first bolt is located on a spanwise axis of the rotor blade. The second bolt is offset from the spanwise axis by a first chordwise distance and is offset from the first bolt by a first spanwise distance. The third bolt is offset from the spanwise axis by a second chordwise distance and is offset from the first bolt by a second spanwise distance.

1 . A rotor hub comprising:
 a rotor blade;   a rotor yoke;   a grip member having an inboard portion, an upper extension, and a lower extension; and   a rotor blade having a root end coupled to the upper extension and the lower extension of the grip member with a first bolt, a second bolt, and a third bolt;   wherein the first bolt is located on a spanwise axis of the rotor blade, the second bolt is offset from the spanwise axis by a first chordwise distance and is offset from the first bolt by a first spanwise distance, the third bolt is offset from the spanwise axis by a second chordwise distance and is offset from the first bolt by a second spanwise distance.   
     
     
         2 . The rotor hub according to  claim 1 , further comprising:
 a pitch horn coupled to the rotor blade.   
     
     
         3 . The rotor hub according to  claim 1 , further comprising:
 a pitch horn at least partially interposed between the upper extension of the grip member and the rotor blade, as well as between the lower extension of the grip member and the rotor blade.   
     
     
         4 . The rotor hub according to  claim 1 , further comprising:
 a pitch horn that is coupled to a pitch link and to a damper, the damper also being coupled to the rotor yoke.   
     
     
         5 . The rotor hub according to  claim 1 , wherein at least one of the first bolt, the second bolt, and the third bolt is a quick release bolt having handle member that can be actuated. 
     
     
         6 . The rotor hub according to  claim 1 , wherein the spanwise axis is the centerline of the rotor blade. 
     
     
         7 . The rotor hub according to  claim 1 , wherein the first spanwise distance is equal to the second spanwise distance. 
     
     
         8 . The rotor hub according to  claim 1 , wherein the first spanwise distance has a dissimilar magnitude to that of the second spanwise distance. 
     
     
         9 . The rotor hub according to  claim 1 , wherein the first chordwise distance is of equal magnitude but opposite direction to the second chordwise distance. 
     
     
         10 . The rotor hub according to  claim 1 , wherein the first chordwise distance is of dissimilar magnitude and opposite direction to the second chordwise distance. 
     
     
         11 . The rotor hub according to  claim 1 , further comprising:
 a first hole, a second hole, and a third hole in the rotor blade, the first hole being located to accept the first bolt, the second hole being located to accept the second bolt, and the third hole being located to accept the third bolt.   
     
     
         12 . The rotor hub according to  claim 11 , further comprising:
 a bushing located in each of the first hole, the second hole, and the third hole.   
     
     
         13 . The rotor hub according to  claim 1 , wherein rotor hub is a main rotor hub for a rotorcraft. 
     
     
         14 . A rotor blade comprising:
 an airfoil member having a root end portion, a tip end portion, a leading edge portion, and a trailing edge portion;   wherein the root end portion includes a first hole, a second hole, and a third hole that are configured for attaching the rotor blade to a rotor hub, the first hole being located on a spanwise axis of the airfoil member, the second hole being offset from the spanwise axis by a first chordwise distance and being offset from the first hole by a first spanwise distance, the third hole being offset from the spanwise axis by a second chordwise distance and being offset from the first hole by a second spanwise distance.   
     
     
         15 . The rotor blade according to  claim 14 , further comprising:
 a bushing located in each of the first hole, the second hole, and the third hole.   
     
     
         16 . The rotor blade according to  claim 14 , wherein the first spanwise distance is equal to the second spanwise distance. 
     
     
         17 . The rotor blade according to  claim 14 , wherein the first spanwise distance has a dissimilar magnitude to that of the second spanwise distance. 
     
     
         18 . The rotor blade according to  claim 14 , wherein the first chordwise distance is of equal magnitude but opposite direction to the second chordwise distance. 
     
     
         19 . The rotor blade according to  claim 14 , wherein the first chordwise distance is of dissimilar magnitude and opposite direction to the second chordwise distance. 
     
     
         20 . The rotor blade according to  claim 14 , wherein the root end includes a first taper and a second taper that form a narrowing of the rotor blade and join at a rounded portion that forms the most inboard part of the airfoil member.