Helicopter rotor blade having a replaceable anhedral tip

A replaceable tip portion for a rotary wing aircraft blade, the blade having a root portion adapted to be connected to a helicopter rotor hub for rotation therewith about an axis of rotation, a central portion of aerodynamic shape connected to and extending outwardly from said root portion, a structural spar extending along the blade longitudinal axis from said root portion to a spar tip end, and a blade skin covering said spar and a blade structural core for defining said central portion aerodynamic shape, the replaceable tip portion comprising:

• an upper tip skin layer;
• a lower tip skin layer;
• a replaceable tip structural core disposed between said upper and lower tip skin layers;
• a recess formed in said replaceable tip structural core for receiving said spar tip end;
• and
• fastening means for securely fastening said spar tip end within said recess, thereby fastening said replaceable tip portion to said blade.

A method for manufacturing a replaceable tip portion for a rotary wing aircraft blade, comprising the steps of:

• providing an upper tip skin mold and a lower tip skin mold, each mold having a lay-up surface for forming a tip skin surface;
• laying-up a plurality of ply layers in each mold, each ply layer comprising composite fibers in a matrix of binder;
• curing said ply layers to form an upper tip skin and a lower tip skin;
• attaching structural core material to said upper tip skin and to said lower tip skin thereby forming an upper tip portion and a lower tip portion;
• forming a recess in said structural core material having an inside diameter which corresponds to the shape of a rotor spar tip end;
• and
• machining said core material along a rotor blade chord plane;
• said machined core providing tight tolerance control in the assembly of said upper and lower tip portions as said replaceable tip portion.