Gas turbine engine and frame

1. A gas turbine engine frame, comprising:

a metallic inner hub;

a metallic outer construction;

a composite flowpath structure that is a separate component from the metallic inner hub and has a primary flowpath structure disposed between said metallic inner hub and said metallic outer construction, wherein the composite flowpath structure includes carbon bismaleimide composites, ceramic matrix composites, metal matrix composites, organic matrix composites and/or carbon-carbon composites; and

a primary composite inner flowpath wall spaced radially apart from a primary composite outer flowpath wall defining the primary flowpath structure for a working fluid of the gas turbine engine;

wherein said composite flowpath structure includes:

a plurality of inner composite struts wherein at least a portion of each inner composite strut extends between said primary composite inner flowpath wall and said primary composite outer flowpath wall;

wherein said composite flowpath structure is formed as a single piece structure.

2. The gas turbine engine frame of claim 1 , further comprising metallic struts extending between said metallic inner hub and said metallic outer construction, wherein said metallic inner hub, said metallic struts and said metallic outer construction are assembled to form a loadpath to transfer engine mechanical loads between said metallic inner hub and said metallic outer construction.

3. The gas turbine engine frame of claim 2 , wherein said load path bypasses said composite flowpath structure, and wherein said composite flowpath structure is configured to be divorced from mechanical loads transferred between said metallic inner hub and said metallic outer construction.

4. The gas turbine engine frame of claim 2 , wherein said gas turbine engine frame is structured to transmit aerodynamic loads from said composite flowpath structure to one of said metallic inner hub, said metallic struts and said metallic outer construction.

5. The gas turbine engine frame of claim 1 , wherein said composite flowpath structure is formed as a single piece structure.

6. The gas turbine engine frame of claim 1 , wherein said composite flowpath structure and said plurality of inner composite struts are integrally formed.

7. The gas turbine engine frame of claim 1 , wherein the composite flowpath structure includes a secondary flowpath structure disposed radially outward of the primary flowpath structure, wherein said secondary flowpath structure includes a secondary composite inner flowpath wall spaced radially apart from a secondary composite outer flowpath wall to define the secondary flowpath structure for working fluid of the gas turbine engine; and

a plurality of outer composite struts wherein at least a portion of each outer composite strut extends between said secondary composite inner flowpath wall and said secondary composite outer flowpath wall.

8. A gas turbine engine, comprising:

a compressor;

a turbine;

an engine frame, said engine frame including a metallic load-bearing structure and a composite flowpath structure, wherein the composite flowpath structure is a separate component from the metallic load-bearing structure, wherein said metallic load-bearing structure defines a loadpath operative to transmit engine mechanical loads to an engine mount of the gas turbine engine, and wherein said composite flowpath structure is divorced from the loadpath, wherein the composite flowpath structure includes carbon bismaleimide composites, ceramic matrix composites, metal matrix composites, organic matrix composites and/or carbon-carbon composites; and

wherein the composite flowpath structure includes a primary composite inner wall spaced apart from a primary composite outer wall to define a primary inner flowpath structure for a working fluid of said gas turbine engine;

wherein said composite flowpath structure further defines a secondary flowpath structure for the working fluid of said gas turbine engine;

wherein said secondary flowpath structure includes a secondary composite outer wall and a secondary composite inner wall disposed radially inward of said secondary composite outer wall;

wherein said composite flowpath structure is formed as a single piece structure.

9. The gas turbine engine of claim 8 , wherein said composite flowpath structure includes a composite strut extending through said secondary flowpath structure.

10. The gas turbine engine of claim 9 , wherein said metallic load-bearing structure includes a metallic strut disposed within said composite strut, and wherein said metallic strut is operative to transmit the engine mechanical loads through the secondary flowpath structure.

11. The gas turbine engine of claim 8 , wherein said metallic load-bearing structure includes:

a metallic inner hub disposed radially inward of said composite flowpath structure;

a metallic outer construction disposed radially outward of said composite flowpath structure; and

a metallic strut extending between said metallic inner hub and said metallic outer construction.

12. The gas turbine engine of claim 11 , further comprising a service tube extending between said metallic inner hub and said metallic outer construction, wherein said service tube is structured to conduct between said metallic inner hub and said metallic outer construction at least one of: pressurized lube oil; scavenge oil; seal charging air; sump vent air; cooling air; a sensor; and a communications link.

13. The gas turbine engine of claim 12 , wherein said composite flowpath structure includes a composite strut disposed at least partially around said service tube.

14. The gas turbine engine of claim 11 , wherein said composite flowpath structure includes a composite strut disposed at least partially around said metallic strut.

15. The gas turbine engine of claim 8 , further comprising at least one composite strut extending between the spaced apart composite primary flowpath structure walls.

16. The gas turbine engine of claim 8 , wherein the metallic load-bearing structure includes an engine mount and a metallic inner hub, and wherein the composite flowpath structure is configured to be divorced from engine mechanical loads transmitted from the metallic inner hub to the engine mount.

17. A gas turbine engine, comprising:

a compressor;

a turbine; and

an engine frame, said engine frame including:

inner and outer primary composite walls defining a composite primary flowpath structure for a working fluid of the gas turbine engine, wherein the composite primary flowpath structure includes carbon bismaleimide composites, ceramic matrix composites, metal matrix composites, organic matrix composites and/or carbon-carbon composites;

means for transmitting engine mechanical loads to an engine mount of the gas turbine engine, wherein the means for transmitting engine mechanical loads includes an inner metallic hub,

wherein the composite primary flowpath structure is a separate component from the metallic inner hub, and

wherein said composite primary flowpath structure is divorced from the engine mechanical loads;

inner and outer secondary composite walls defining a secondary flowpath structure for a working fluid of the gas turbine engine; wherein the secondary flowpath structure is positioned radially outward of the primary flowpath structure;

wherein said composite primary flowpath structure is formed as a single piece structure.

18. The gas turbine engine of claim 17 , further comprising

an inner composite strut connected between the inner and outer primary composite walls; and

an outer composite strut connected between the inner and outer secondary composite walls.

19. The gas turbine engine of claim 17 , wherein the composite primary flowpath structure and the composite secondary flowpath structure are configured to be divorced from engine mechanical loads transferred from the inner metallic hub to the engine mount.