A propulsion assembly for a rotorcraft includes a raceway having a tapered inner surface and a mast configured to receive the raceway at a raceway receiving station. The mast has a tapered outer surface at the raceway receiving station. The propulsion assembly includes a mast bearing assembly having a plurality of bearings facing the mast to engage the raceway. The tapered inner surface of the raceway is friction welded to the tapered outer surface of the mast at the raceway receiving station to form a tapered friction weld line.

Various examples are provided related to flight duration enhancement for rotorcraft and multicopters. In one example, a rotorcraft or multicopter includes one or more rotors, and one or more nozzles positioned in relationship to at least one corresponding rotor. The one or more nozzles can modulate, reshape, redirect, or adjust downwash produced by the corresponding rotor. The one or more nozzles can dynamically modulate, reshape, redirect, or adjust the downwash below the rotorcraft or multicopter. The one or more nozzles can be morphed or reshaped to dynamically modulate, reshape, redirect, or adjust the downwash using, e.g., a stochastic optimization framework and/or a motif-based auto-controller.

Various examples are provided related to flight duration enhancement for rotorcraft and multicopters. In one example, a rotorcraft or multicopter includes one or more rotors, and one or more nozzles positioned in relationship to at least one corresponding rotor. The one or more nozzles can modulate, reshape, redirect, or adjust downwash produced by the corresponding rotor. The one or more nozzles can dynamically modulate, reshape, redirect, or adjust the downwash below the rotorcraft or multicopter. The one or more nozzles can be morphed or reshaped to dynamically modulate, reshape, redirect, or adjust the downwash using, e.g., a stochastic optimization framework and/or a motif-based auto-controller.

A method for controlling a hybrid helicopter having at least one lifting rotor, at least one forward-movement propeller and an empennage provided with at least one moveable empennage surface. The method includes the following steps: using a main sensor to determine a current value of a rotor parameter conditioning a current power drawn by the lifting rotor, using an estimator to determine a current setpoint of the rotor parameter, adjusting a position of the moveable empennage surface using a deflection controller as a function of the current value and of current setpoint.

A method for controlling a hybrid helicopter having at least one lifting rotor, at least one forward-movement propeller and an empennage provided with at least one moveable empennage surface. The method includes the following steps: using a main sensor to determine a current value of a rotor parameter conditioning a current power drawn by the lifting rotor, using an estimator to determine a current setpoint of the rotor parameter, adjusting a position of the moveable empennage surface using a deflection controller as a function of the current value and of current setpoint.

A rotary wing aircraft with a fuselage that forms an aircraft interior region, the fuselage comprising an upper primary skin that separates the aircraft interior region from an aircraft upper deck arranged above the fuselage, wherein the aircraft upper deck comprises an engine accommodating region with a firewall arrangement, the engine accommodating region accommodating at least one aircraft engine within the firewall arrangement, wherein the firewall arrangement comprises at least one gasket for tightening pass-through of a torque tube that connects the at least one aircraft engine to a main gear box of the rotary wing aircraft, and wherein the at least one gasket comprises at least two fire proof shells and a ring-shaped flexible fire proof bellows.

A wind estimation system for an aircraft includes a first sensor configured to sense a first position associated with an aircraft control component in a wind condition, a second sensor configured to sense a first configuration associated with a rotor system of the aircraft in the wind condition, and at least one controller in communication with at least one of the first sensor or the second sensor. The at least one controller is configured to determine a tip-path-plane angle of the aircraft based on the first position and the first configuration, and determine at least one of a current wind speed or current wind direction based on the tip-path-plane angle.

The present invention includes an apparatus for preventing aircraft rollover upon a water landing comprising: a deployable first and/or second boom affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis of the aircraft; and a first and/or second air bladder attached to a second end of the first and/or second boom, wherein the first and/or second air bladders are configured to inflate when an aircraft lands in the water, wherein deployment of the first and second boom and air bladder prevents aircraft rollover upon water landing; or a deployable keel affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor of the aircraft upon a water landing, wherein the keel is sized to prevent aircraft rollover upon deployment; or both.

The present invention includes an apparatus for preventing aircraft rollover upon a water landing comprising: a deployable first and/or second boom affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis of the aircraft; and a first and/or second air bladder attached to a second end of the first and/or second boom, wherein the first and/or second air bladders are configured to inflate when an aircraft lands in the water, wherein deployment of the first and second boom and air bladder prevents aircraft rollover upon water landing; or a deployable keel affixed by a first end to the aircraft and capable of deployment substantially perpendicular to a longitudinal axis and opposite a rotor of the aircraft upon a water landing, wherein the keel is sized to prevent aircraft rollover upon deployment; or both.

Systems and methods for moving an illumination spot of a searchlight beam at a constant groundspeed. The method includes receiving state data comprising an attitude for the mobile platform. The method computes an elevation angle, theta, of the beam as a function of the attitude, an elevation actuator angle and a known mounting orientation for the searchlight. Responsive to receiving a searchlight control command from a user input device, the method determines a respective rate of change of theta, dtheta/dt, and rate of change of Psi, dPsi/dt, required to maintain the constant groundspeed of the illumination spot, as a function of the state data. The method updates theta responsive to the determined dtheta/dt and generates actuator control commands for an elevation actuator based thereon. The method updates Psi responsive to the determined dPsi/dt, and generates actuator control commands for an azimuth actuator based thereon.