Hybrid metal fan blade

摘要

A fan blade is disclosed comprising a lightweight metallic airfoil portion and a high-strength sheath portion. The airfoil portion has a forward airfoil edge, a first airfoil surface, and a second airfoil surface. The sheath portion has a sheath head section, a first sheath flank, and a second sheath flank, both flanks extending chordwise from the forward sheath section. The sheath portion is bonded to the airfoil portion such that the sheath head section covers the forward airfoil edge, defining a blade leading edge. The first sheath flank covers a portion of the first airfoil surface proximate the airfoil forward edge, jointly defining a blade suction surface. The second sheath flank covers a portion of the second airfoil surface proximate the airfoil forward edge, jointly defining a blade pressure surface.

主权项

1. A blade comprising:
an airfoil portion formed from a monolithic first metallic material, the airfoil portion having a forward airfoil edge, a first airfoil surface, and a second airfoil surface, each airfoil surface extending from proximate a platform to proximate a blade tip edge; a sheath portion formed from a second metallic material, the sheath portion having a solid sheath head section, a first sheath flank and a second sheath flank, the solid sheath head section extending chordwise forwardly from the forward airfoil edge, and both flanks extending chordwise rearwardly from a junction of the sheath head section and the forward airfoil edge such that the sheath head section defines a thickness of the blade forward of the forward airfoil edge up to and including a blade leading edge continuously from proximate the platform and terminating proximate the blade tip edge; and a dielectrically protective nylon-based scrim sheet disposed between the sheath portion and the airfoil portion; wherein the first metallic material is an aluminum alloy; wherein the sheath portion is a single piece bonded to the airfoil portion such that the sheath head section covers the forward airfoil edge; the first sheath flank covers a portion of the first airfoil surface proximate the airfoil forward edge, jointly defining a blade suction surface; and the second sheath flank covers a portion of the second airfoil surface proximate the airfoil forward edge, jointly defining a blade pressure surface opposite the blade suction surface; and wherein a chordwise dimension of the sheath head section is at least 3% of a chordwise blade dimension in an inner span region, and at least 8% of a chordwise blade dimension in a distal span region.