Vane with collar

1. An airfoil piece, comprising:

at least one inner ceramic matrix composite ply defining an internal cavity of an airfoil section and first and second collar projections, the at least one inner ceramic matrix composite ply continuous through the airfoil section and first and second collar projections;

first and second platforms at first and second ends of the airfoil section, wherein the first and second collar projections extend radially past the first and second platforms, respectively, wherein the first collar projection has a length in the radial dimension that is longer than a length of the second collar projection in the radial dimension.

2. The airfoil piece of claim 1 , further comprising:

a first outer ceramic matrix composite ply, the first outer ceramic matrix composite ply surrounding the inner ceramic matrix composite ply at the first collar projection and defining a radially outer surface of the first platform; and

a second outer ceramic matrix composite ply, the second outer ceramic matrix composite ply surrounding the inner ceramic matrix composite ply at the second collar projection and defining a radially inner surface of the second platform.

3. The airfoil piece of claim 2 , further comprising a third outer ceramic matrix composite ply defining a radially inner surface of the first platform and a radially outer surface of the second platform, and surrounding the inner ceramic matrix composite ply.

4. The airfoil piece of claim 3 , further comprising a middle ceramic matrix composite ply surrounding substantially the entire radial length of the inner ceramic matrix composite ply.

5. The airfoil piece of claim 1 , wherein the at least one inner ceramic matrix composite ply includes a first inner ceramic matrix composite ply defining a first cavity and a second inner ceramic matrix composite ply defining a second cavity.

6. The airfoil piece of claim 5 , further comprising a middle ceramic matrix composite ply surrounding the first and second inner ceramic matrix composite plies to define the airfoil section.

7. The airfoil piece of claim 1 , wherein the first inner ceramic matrix composite ply comprises ceramic-based fibers in a ceramic-based matrix, and at least some of the fibers are continuous through the first and second collar projections and the airfoil section.

8. A vane for a gas turbine engine, comprising:

an airfoil piece, including:

an inner ceramic matrix composite ply defining an airfoil cavity;

a middle ceramic matrix composite ply surrounding the inner ceramic matrix composite ply; and

an outer ceramic matrix composite ply surrounding the middle ply, the outer ply defining first and second platforms, wherein the inner and middle plies extend past the first and second platforms to form first and second collar projections, respectively, wherein the first collar projection has a length in the radial dimension that is longer than a length of the second collar projection in the radial dimension; and

a spar piece, the spar piece including a hollow spar situated in the airfoil cavity and a spar platform, the spar platform including a pocket, wherein the first collar projection is situated in the pocket.

9. The vane of claim 8 , wherein the first collar projection is a radially outer collar projection and the second collar projection is a radially inner collar projection.

10. The vane of claim 8 , wherein the outer ply is a first outer ply and the first outer ply defines a radially inner side of the first platform and a radially outer side of the second platform, and further comprising a second outer ply defining a radially outer side of the first platform and a third outer ply defining a radially inner side of the second platform.

11. The vane of claim 10 , wherein the second and third outer plies surround the middle ply in the first and second collar projections, respectively.

12. The vane of claim 8 , wherein the airfoil cavity is a first airfoil cavity and the inner ceramic matrix composite ply is a first inner ply, and further comprising a second airfoil cavity defined by a second inner ply, wherein the middle ply surrounds the first and second inner plies.

13. The vane of claim 8 , wherein the spar piece is metallic.

14. The airfoil vane of claim 8 , wherein the spar piece is configured to transfer structural loads from the airfoil piece to a support structure.

15. A method of assembling a vane, comprising:

inserting a spar piece into a cavity of a hollow airfoil section of an airfoil piece, the cavity defined by an inner ceramic matrix composite ply, wherein a middle ceramic matrix composite ply surrounds the inner ceramic matrix composite ply, and an outer ceramic matrix composite ply surrounds the middle ply, the outer ply defining first and second platforms, wherein the inner and middle plies extend past the first and second platforms to form first and second collar projections, wherein the first collar projection has a length in the radial dimension that is longer than a length of the second collar projection in the radial dimension.

16. The method of claim 15 , wherein the inserting includes aligning a pocket in a spar platform of the spar piece with the first collar projection.

17. The method of claim 16 , wherein the outer ply is a first outer ply and the first outer ply defines a radially inner side of the first platform and a radially outer side of the second platform, and further comprising a second outer ply defining a radially outer side of the first platform and a third outer ply defining a radially inner side of the second platform.

18. The method of claim 15 , wherein the spar piece is metallic.