A multiple piece turbine airfoil having an outer shell with an airfoil tip that is attached to a root with an internal structural spar is disclosed. The root may be formed from first and second sections that include an internal cavity configured to receive and secure the one or more components forming the generally elongated airfoil. The internal structural spar may be attached to an airfoil tip and place the generally elongated airfoil in compression. The configuration enables each component to be formed from different materials to reduce the cost of the materials and to optimize the choice of material for each component.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Development of this invention was supported in part by the United States Department of Energy, Contract No. DE-FC26-05NT42646. Accordingly, the United States Government may have certain rights in this invention.