A pneumatic actuator can include a housing and an actuator shaft disposed within the housing and configured to actuate between a first position and a second position. The pneumatic actuator can include a single bushing located within the housing between the housing and the actuator shaft. The single bushing can be configured to support the actuator shaft without the actuator shaft being supported at a second location while allowing actuator motion under set operating conditions.

During a cruise mode, a cruise-only propeller provides thrust using power from a first power source. During a hovering mode and a transitional mode, the propeller provides no thrust. The first power source includes an internal combustion engine; a second power source includes a high discharge rate battery and a high energy battery. The propeller is electrically connected to the first power source and is electrically disconnected from the second power source. During the hovering mode and the transitional mode, a hover-and-transition-only tiltrotor provides thrust using power from the second power source. During a vertical landing, the tiltrotor switches power sources from the high energy battery to the high discharge rate battery, independent of current draw. The tiltrotor is electrically disconnected from the first power source and is electrically connected to the second power source. During the cruise mode, the tiltrotor provides no thrust.

During a cruise mode, a cruise-only propeller provides thrust using power from a first power source. During a hovering mode and a transitional mode, the propeller provides no thrust. The first power source includes an internal combustion engine; a second power source includes a high discharge rate battery and a high energy battery. The propeller is electrically connected to the first power source and is electrically disconnected from the second power source. During the hovering mode and the transitional mode, a hover-and-transition-only tiltrotor provides thrust using power from the second power source. During a vertical landing, the tiltrotor switches power sources from the high energy battery to the high discharge rate battery, independent of current draw. The tiltrotor is electrically disconnected from the first power source and is electrically connected to the second power source. During the cruise mode, the tiltrotor provides no thrust.

A triplex pneumatic architecture system is disclosed having first, second, and third pneumatic subsystems where triplex redundancy may be accomplished by measuring only one particular node in each system, such as a measured current of the servo valve. Each of the first, second, and third pneumatic subsystems are configured to control a separate redundant pneumatic actuation assembly. Each subsystem may comprise a current sensor to measure a control current from a servo driver to a servo valve that controls the pneumatic actuation assembly to output a measured current value, and a dump valve coupled to a relay. Each processor is configured to generate a termination signal to actuate the first relay to open the first dump valve. The triplex pneumatic architecture system further includes a communication bus to communicatively couple each of the first, second, and third pneumatic subsystems. Each processor is configured to generate the termination signal and to communicate the termination signal to one or more of the relays when one measured current value deviates from the two other measured current values by a predetermined error value.

One example of an actuation system includes a pneumatic muscle connected to a component to be actuated. The system also includes an actuation member connected in series to the pneumatic muscle and valve connected to the pneumatic muscle to control a pressure in the pneumatic muscle. The system also includes a positioning mechanism connected to the component to control a movement of the component and a controller connected to the pneumatic muscle, the valve, and the positioning mechanism, the controller to control actuation of the component by controlling the pressure in the pneumatic muscle.

A vehicle includes a tilt rotor that is aft of a fixed wing and that is attached to the fixed wing via a pylon. A flight computer configured to instruct the tilt rotor to produce a maximum downward angle including by updating an actuator authority database associated with the flight computer to reflect the maximum downward angle, and generating a rotor control signal for the tilt rotor using the updated actuator authority database that reflects the maximum downward angle, wherein the maximum downward angle is adjustable.

A vehicle includes a tilt rotor that is aft of a fixed wing and that is attached to the fixed wing via a pylon. A flight computer configured to instruct the tilt rotor to produce a maximum downward angle including by updating an actuator authority database associated with the flight computer to reflect the maximum downward angle, and generating a rotor control signal for the tilt rotor using the updated actuator authority database that reflects the maximum downward angle, wherein the maximum downward angle is adjustable.

A landing gear system for an aircraft includes a retractable landing gear assembly, a hydraulic actuator for actuating movement part, for example a bogie of the landing gear assembly, and an accumulator associated with the actuator. The accumulator comprises a volume of pressurised gas separated from hydraulic fluid by a separator piston. Travel of the separator piston beyond a certain position is indicative of a fault. The accumulator includes a snubbing device that acts to slow movement of the separator piston beyond that position. A monitoring system measures the time taken for the movement of the landing gear part effected by the hydraulic actuator. If the measured time is longer than a threshold time, that is indicative of a possible fault in the accumulator, that might, without the snubbing, remain undetected and/or hidden from view.

A method includes receiving pump cycle location data associated with a fluid power system. The fluid power system includes a plurality of pumps (including at least a first pump, a second pump, and a third pump). Based on the pump cycle location data having a first value, the method includes activating the first pump as a primary pump. Based on the pump cycle having a second value, the method includes activating the second pump as the primary pump. The method also includes activating the third pump as a secondary pump when the fluid power system is in a multiple-pump operating mode.

A method includes receiving pump cycle location data associated with a fluid power system. The fluid power system includes a plurality of pumps (including at least a first pump, a second pump, and a third pump). Based on the pump cycle location data having a first value, the method includes activating the first pump as a primary pump. Based on the pump cycle having a second value, the method includes activating the second pump as the primary pump. The method also includes activating the third pump as a secondary pump when the fluid power system is in a multiple-pump operating mode.