Abstract: A conversion system for a tiltrotor aircraft may be configured to control tilting of a pylon assembly relative to a wing of the aircraft. The system may include a means for generating asymmetric thrust with a propulsion rotor carried by the pylon assembly to generate a first torque on the pylon assembly in a first direction. The system may include a brake mechanism to selectively resist the first torque on the pylon assembly by applying a second torque to the pylon assembly in a second direction opposite the first direction. The rotor (via asymmetric thrust generated by the rotor) and the brake mechanism are coordinated to work against each other to control the tilt rate and angle of the pylon assembly during conversion between flight modes of the tiltrotor aircraft. Other aspects of the present technology include methods of tilting rotors of tiltrotor aircraft using asymmetric thrust and brake mechanisms.

Abstract: A shaft assembly (which may be a rotor mast for a rotorcraft) may include a shaft body formed with composite material and one or more metal fittings attached to the shaft body. A metal fitting may include an interior opening with a cross-section having a non-circular perimeter (such as an oval or an ellipse). The interior opening may also include contouring, such as a first tapered section in which the fitting converges toward the longitudinal axis of the shaft body and a second tapered section in which the fitting diverges from the longitudinal axis.

Abstract: A shaft assembly (which may be a rotor mast for a rotorcraft) may include a shaft body formed with composite material and one or more metal fittings attached to the shaft body. A metal fitting may include an interior opening with a cross-section having a non-circular perimeter (such as an oval or an ellipse). The interior opening may also include contouring, such as a first tapered section in which the fitting converges toward the longitudinal axis of the shaft body and a second tapered section in which the fitting diverges from the longitudinal axis.