A variable pitch fan assembly includes a plurality of rotating trunnion assemblies, a plurality of counterweight assemblies, a first unison ring gear engaged with the trunnion assemblies, and a second unison ring member that restricts out of synch movement of the counterweights relative to each other.

There is described herein methods and systems for testing a propeller feathering function. The method comprises monitoring a rotational speed over time of propeller blades of an aircraft, commanding an angle change of the propeller blades, comparing a post-angle change rotational speed of the propeller blades to an expected rotational speed without the commanded angle change and obtaining, by the processor, a rotational speed difference, and issuing a test passed signal when the rotational speed difference exceeds a threshold and a test failed signal when the rotational speed difference does not exceed the threshold.

A proprotor blade for a ducted aircraft including a duct includes a main body having a distal end and a sacrificial blade tip coupled to the distal end of the main body. The sacrificial blade tip includes a deformable core material and a shell layer at least partially covering the deformable core material. The sacrificial blade tip deforms upon contact with the duct, thereby reducing damage to the ducted aircraft.

A propeller system including a propeller including a central attachment member and a plurality of blade apparatuses, each including a blade body attached to the central attachment member and a magnetic coupling member attached to a radially outward end of the blade body. The propeller system further comprises a propeller frame configured to at least partially circumscribe the magnetic coupling member of each blade apparatus and a plurality of electromagnets positioned on the propeller frame and operable to generate magnetic fields to suspend the magnetic coupling members, laterally translate the magnetic coupling members, rotate the magnetic coupling members along the radial axis of the propeller system, thereby rotating the blade bodies.

An exemplary length adjustable link includes a tube having an internal bore and internal surface, a first rod end having a first shaft disposed in a first end of the internal bore, a second rod end having a second shaft disposed in a second end of the internal bore, and a member threadably connecting the first rod end to the second rod end.

An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes an airframe having first and second wings with first and second pylons extending therebetween. The first and second wings each having first and second outboard nacelle stations. A two-dimensional distributed thrust array is attached to the airframe. The thrust array including a plurality of outboard propulsion assemblies coupled to the first and second outboard nacelle stations of the first and second wings. A flight control system is coupled to the airframe and is operable to independently control each of the propulsion assemblies. A cargo hook module is coupled to the airframe. The cargo hook module is operable for external load operations.

One embodiment is a rotor system comprising a duct ring; a hub disposed centrally to the duct ring; first and second stators each connected between the duct ring and the hub; first and second control vanes rotatably connected to the first and second stators, respectively; and a structural hoop having a first end connected to the first control vane and a second end connected to the second control vane, the structural hoop for translating rotation of the first control vane about a vane axis to the second control vane.

One embodiment is a rotor system comprising a duct ring; a hub disposed centrally to the duct ring; first and second stators each connected between the duct ring and the hub; first and second control vanes rotatably connected to the first and second stators, respectively; and a structural hoop having a first end connected to the first control vane and a second end connected to the second control vane, the structural hoop for translating rotation of the first control vane about a vane axis to the second control vane.

A proprotor system for a ducted aircraft includes a duct and proprotor blades surrounded by the duct. Each proprotor blade is rotatable about a respective pitch change axis. The proprotor blades are configured to change collective pitch about the pitch change axes. The proprotor blades are extendable along the pitch change axes into various positions including a retracted position and an extended position. The proprotor blades change between the retracted position and the extended position based on the collective pitch of the proprotor blades, thereby controlling a tip gap between the proprotor blades and the duct.

A variable pitch bladed disc including a plurality of blades, each being of variable pitch about a blade axis of rotation and having a root, the plurality of blades including at least one first blade and at least one second blade, a plurality of rotor connecting shafts, each shaft having a root and a tip, the root of each blade being mounted on the tip of a corresponding rotor connecting shaft via a pivot so as to allow each blade to be rotated about the blade axis of rotation, the first blade having a first rotation axis inclination such that the rotation axis thereof is inclined in a fixed manner with respect to a radial axis passing through the root of the corresponding shaft, and the second blade has a second rotation axis inclination different from the first rotation axis inclination.