Composite airfoil assembly for an interdigitated rotor

Rotor assemblies and methods for manufacturing airfoils for rotor assemblies are provided. For example, a rotor assembly comprises a rotary structure extending circumferentially about an axial centerline of a gas turbine engine, an airfoil having a root and a tip, and a pin extending through the root. The root is coupled to the rotary structure and has a bulbous shape, and the airfoil is formed from a plurality of composite plies. The pin defines both a planar first surface and a planar second surface on a pin body having a generally circular cross-section. Further, the pin includes a first end and a second end that contact the rotary structure. The first and second surfaces together form a point that is oriented toward the tip of the airfoil. In one embodiment, the rotary structure is an outer rotor of an interdigitated rotor assembly and the airfoil extends radially inward.