Threaded full ring inner air-seal

1. A turbine section comprising:

first and second turbine rotors each carrying turbine blades for rotation about a central axis, said rotors each having at least one rotating seal at a radially inner location;

a vane assembly including a vane extending radially from a platform;

an air seal attached to the vane assembly, the air seal comprising a ring extending circumferentially about the axis; and

a ring nut received on the air seal for securing the air seal to the vane assembly.

2. The turbine section as recited in claim 1 , wherein the air seal includes mating features for circumferentially locating the air seal relative to the vane assembly.

3. The turbine section as recited in claim 1 , including a full ring seal disposed between a surface of the vane platform and the ring nut.

4. The turbine section as recited in claim 1 , including a lock ring engaged to the air seal and the ring nut for securing a relative position between the ring nut and the air seal.

5. The turbine section as recited in claim 1 , including a wire seal disposed between the ring nut and a surface of the air seal.

6. The turbine section as recited in claim 1 , wherein the platform includes a radially inward extending rim engaging a forward lip of the air seal.

7. The turbine section as recited in claim 6 , wherein the air seal includes a forward wall with openings for exhausting air flow.

8. A vane assembly comprising:

a vane including an inner platform having a mount rail extending radially inwardly;

an air seal attached to the inner platform of the vane section, the air seal comprising a ring extending circumferentially about the axis including centering tabs receiving lugs disposed on the mount rail; and

a ring nut received on the air seal and engaged to the mount rail for securing the air seal to the vane section.

9. The vane assembly as recited in claim 8 , including a full ring seal disposed between a surface of the inner platform and the ring nut.

10. The vane assembly as recited in claim 9 , wherein the mount rail and the ring nut define a seal cavity and the full ring seal is disposed within the seal cavity.

11. The vane assembly as recited in claim 8 , including a lock ring engaged to the air seal and the ring nut for securing a relative position between the ring nut and the air seal.

12. The vane assembly as recited in claim 8 , including a wire seal disposed between the ring nut and a surface of the air seal.

13. The vane assembly as recited in claim 12 , wherein air seal includes a front wall with openings for exhausting cooling air flow.

14. The vane assembly as recited in claim 8 , wherein the inner platform includes a radially inward extending rim engaging a forward lip of the air seal.

15. A method of assembling a vane assembly comprising:

defining a plurality of vanes circumferentially about an axis that extend from an inner platform;

abutting a front hub of the inner platform against a lip of an air seal; and

loading the front hub against the lip of the air seal with a ring nut threaded onto the air seal.

16. The method as recited in claim 15 , including the step of engaging a plurality of tabs on a lock ring with the ring nut to hold a position of the ring nut relative to the air seal.

17. The method as recited in claim 15 , including sealing between the ring nut and a mount rail of the inner platform.

18. The method as recited in claim 15 , including defining a cooling air chamber between the air seal and the inner platform and exhausting cooling air flow from openings within the air seal.