Patent ID: 8920127

Claim:
An engine disk and blade combination comprising: a metallic disk having: a plurality of first blade attachment slots; and a plurality of second blade attachment slots, circumferentially interspersed with the first attachment slots; a circumferential array of first blades, each first blade comprising: an airfoil; and an attachment root, the attachment root received in an associated respective said first attachment slot; and a circumferential array of second blades, each second blade comprising: an airfoil; and an attachment root, the attachment root received in an associated respective said second attachment slot, wherein: the first blades and second blades are non-metallic; the first blades are radially longer than the second blades; the first slots are radially deeper than the second slots; tips of the first blades are at like radial positions to tips of the second blades at a given axial position; the first blades have a characteristic chord; the second blades have a characteristic chord, less than the characteristic chord of the first blades; the first slots have a first circumferential span; and the second slots have a second circumferential span, less than the first circumferential span.