A turbomachine includes a rotatable annular outer drum rotor connected to a first plurality of blades. Each of the first plurality of blades includes a blade root portion secured to the rotatable annular outer drum rotor. Each of the blade root portions includes one or more structural radial retention features for radially retaining each of the blade root portions within the rotatable annular outer drum and one or more axial retention features for axially retaining each of the blade root portions within the rotatable annular outer drum.

An airfoil for a gas turbine engine according to an example of the present disclosure includes, among other things, an airfoil section that extends from a root section. The airfoil section extends between a leading edge and a trailing edge in a chordwise direction and extends between a tip portion and the root section in a radial direction. The airfoil section defines a pressure side and a suction side separated in a thickness direction, and the airfoil section includes a metallic sheath that defines an internal cavity receiving a composite core. The root section defines at least one bore dimensioned to receive a retention pin. At least one damping element is received in the internal cavity and that selectively causes the airfoil section to stiffen.

The present disclosure is directed to an outer drum rotor assembly for a gas turbine engine including a first outer drum and a second outer drum. Each outer drum defines a radially extended flange adjacent to one another. A plurality of outer drum airfoils is extended inward along the radial direction from between the first outer drum and the second outer drum at the flange.

An airfoil for a gas turbine engine according to an example of the present disclosure includes, among other things, an airfoil section extending from a root section. The airfoil section includes a sheath that receives a core. The core includes first and second ligaments received in respective internal channels defined by the sheath, and each one of the first and second ligaments includes at least one interface portion in the root section dimensioned to receive a retention pin.

A rotor assembly for a gas turbine engine includes, among other things, a rotatable hub that has a metallic main body that extends along a longitudinal axis, and that has an array of annular flanges that extend about an outer periphery of the main body to define an array of annular channels along the longitudinal axis. Each of the annular channels receives a composite reinforcement member that extends about the outer periphery of the hub.

A fan platform includes a platform body that has gaspath and non-gaspath sides, leading and trailing ends, first and second circumferential sides that are contoured to follow profiles of adjacent fan blades, and lugs that project from the non-gaspath side and define fastener openings. The platform body includes a core and a fiber-reinforced polymer matrix composite skin attached on the core at least on portions of the gaspath and non-gaspath sides.

A rotor assembly is provided for a gas turbine engine. This rotor assembly includes a first rotor disk, a second rotor disk, a plurality of rotor blades and a plurality of disk mounts. The first rotor disk is configured to rotate about a rotational axis. The second rotor disk is configured to rotate about the rotational axis. The rotor blades are arranged circumferentially around the rotational axis. Each of the rotor blades is mounted to the first rotor disk and to the second rotor disk. The rotor blades include a first rotor blade. Each of the disk mounts connects the first rotor disk and the second rotor disk together. The disk mounts include a first disk mount that further supports the first rotor blade.

A rotor blade is provided for a gas turbine engine. This rotor blade includes a rotor blade pair including a mount, a first airfoil and a second airfoil. The mount includes a forked body with a first leg and a second leg. The first airfoil is connected to the first leg. The second airfoil is connected to the second leg and arranged circumferentially next to the first airfoil.

A wheel assembly for a gas turbine engine includes a disk, a plurality of blades, and a plurality of platforms. The disk is configured to rotate about an axis during operation of the gas turbine engine. Each of the plurality of blades includes a root received in the disk and an airfoil that extends radially away from the root. The platforms are arranged around the blades to define a boundary of a flow path of the gas turbine engine.

A rotor assembly for a gas turbine engine includes a rotatable hub that has a main body and an array of annular flanges that extend about an outer periphery of the main body to define an array of annular channels. An array of airfoils are circumferentially distributed about the outer periphery. Each one of the airfoils includes an airfoil section extending from a root section received in the annular channels. Retention pins extend through the root section of a respective one of the airfoils and through the array of annular flanges to mechanically attach each root section to the hub.