ROTOR BLADE AND METHOD FOR FORMING A ROTOR BLADE

1 . An apparatus for a rotor assembly with a rotational axis, the apparatus comprising:

a rotor blade including an airfoil, a neck and an attachment;

the neck radially connecting the airfoil and the attachment; and

the attachment extending axially between an attachment first axial side and an attachment second axial side, a first end portion of the attachment projecting axially out from the neck to the attachment first axial side, and a second end portion of the attachment projecting axially out from the neck to the attachment second axial side.

2 . The apparatus of claim 1 , wherein

the first end portion of the attachment is configured as a first cantilevered projection; and

the second end portion of the attachment is configured as a second cantilevered projection.

3 . The apparatus of claim 1 , wherein

the rotor blade further includes a platform;

a first gap, located axially adjacent the neck, extends radially between the first end portion of the attachment and the platform; and

a second gap, located axially adjacent the neck, extends radially between the second end portion of the attachment and the platform.

4 . The apparatus of claim 1 , wherein the rotor blade comprises ceramic.

5 . The apparatus of claim 1 , wherein the rotor blade comprises metal.

6 . The apparatus of claim 1 , wherein the attachment has a flared cross-sectional geometry.

7 . The apparatus of claim 1 , further comprising:

an attachment preform configured to form a base of the attachment; and

a sheet of material wrapped about the attachment preform to form a portion of the attachment and a portion of the airfoil.

8 . The apparatus of claim 7 , wherein the attachment preform has a triangular cross-sectional geometry.

9 . The apparatus of claim 7 , wherein the attachment preform is a tubular attachment preform.

10 . The apparatus of claim 7 , wherein the attachment preform comprises an outer shell surrounding filler material.

11 . The apparatus of claim 7 , wherein opposing distal ends of the sheet of material are located at a tip of the airfoil.

12 . The apparatus of claim 7 , further comprising a second sheet of material wrapped about the attachment preform and over the sheet of material to form a second portion of the attachment and a portion of a platform of the rotor blade.

13 . The apparatus of claim 12 , wherein opposing distal ends of the second sheet of material are located at opposing lateral ends of the platform.

14 . The apparatus of claim 12 , further comprising a third sheet of material covering the second sheet of material to form a third portion of the attachment, a portion of the neck and a second portion of the platform.

15 . The apparatus of claim 14 , wherein opposing distal ends of the third sheet of material are located on a common lateral side of the rotor blade.

16 . The apparatus of claim 1 , wherein the rotor blade is configured with an internal cooling passage.

17 . A manufacturing method, comprising forming a rotor blade for a rotor assembly with a rotational axis, wherein

the rotor blade includes an airfoil, a neck and an attachment;

the neck radially connects the airfoil and the attachment; and

the attachment extends axially between an attachment first axial side and an attachment second axial side, a first end portion of the attachment projects axially out from the neck to the attachment first axial side, and a second end portion of the attachment projects axially out from the neck to the attachment second axial side.

18 . A manufacturing method, comprising forming a rotor blade for a rotor assembly with a rotational axis, the forming comprising

providing an attachment preform to form a base of an attachment of the rotor blade;

wrapping a first sheet of material about the attachment preform to form a first portion of the attachment and a portion of an airfoil of the rotor blade; and

wrapping a second sheet of material about the attachment preform and over the first sheet of material to form a second portion of the attachment and a portion of a platform of the rotor blade.

19 . The manufacturing method of claim 18 , wherein the forming further comprises layering a third sheet of material over the second sheet of material to form a third portion of the attachment, a portion of a neck of the rotor blade and a second portion of the platform.

20 . The manufacturing method of claim 18 , wherein

the attachment extends axially between an attachment first axial side and an attachment second axial side;

an axial first end portion of the attachment projects axially out from a neck of the rotor blade to the attachment first axial side; and

an axial second end portion of the attachment projects axially out from the neck to the attachment second axial side.