Abstract: A system for controlling a propeller having a plurality of blades having a primary control system and a backup control system. The primary control system including a sensor responsive to a propeller state, and a controller connected to the sensor and to an electrohydraulic control actuator. The electrohydraulic control actuator is connected via a bypass valve to a hydraulic actuator that controls at least a blade angle of a blade of the propeller. The controller generating commands to the electrohydraulic control actuator based on at least the propeller state. The backup control system including a second controller, an electrohydraulic solenoid operably connected to the bypass valve. The backup control system is operable to hydraulically disable the primary control system via the bypass valve upon the occurrence of a selected condition, the second controller modulates the operation of the electrohydraulic solenoid to control the bypass actuator based on the propeller state.

Abstract: A system is provided. The system includes a dual piston actuator and valves. The dual piston actuator includes a primary actuator and a protection actuator. The primary and protection actuators move to increase and decrease a pitch of propellers of an aircraft with respect to a supply of first and second mediums. The valves include a first check valve, a second check valve, and a third valve. The third valve operates between a first mode and a protection mode. The second medium is directed to the primary and protection actuators through the first and second check valves by the third valve when the third valve is operating in a protection mode.

Abstract: A system is provided. The system includes a dual piston actuator and valves. The dual piston actuator includes a primary actuator and a protection actuator. The primary and protection actuators move to increase and decrease a pitch of propellers of an aircraft with respect to a supply of first and second mediums. The valves include a first check valve, a second check valve, and a third valve. The third valve operates between a first mode and a protection mode. The second medium is directed to the primary and protection actuators through the first and second check valves by the third valve when the third valve is operating in a protection mode.

Abstract: An aerodynamic blade is provided and includes a blade body and a light module. The blade body includes an inboard end and a tip outboard of the inboard end. The blade body is connectable with a hub at the inboard end such that rotations of the hub drive rotations of the tip about a rotational axis. The light module is disposed in the tip and configured to activate in response to the rotations of the tip about the rotational axis to emit light visible at an exterior of the blade body.

Abstract: An aerodynamic blade is provided and includes a blade body and a light module. The blade body includes an inboard end and a tip outboard of the inboard end. The blade body is connectable with a hub at the inboard end such that rotations of the hub drive rotations of the tip about a rotational axis. The light module is disposed in the tip and configured to activate in response to the rotations of the tip about the rotational axis to emit light visible at an exterior of the blade body.

Abstract: A system for controlling a propeller having a plurality of blades having a primary control system and a backup control system. The primary control system including a sensor responsive to a propeller state, and a controller connected to the sensor and to an electrohydraulic control actuator. The electrohydraulic control actuator connected via a bypass valve to a hydraulic actuator that controls at least a blade angle of a blade of the propeller. The controller generating commands to the electrohydraulic control actuator based on at least the propeller state. The backup control system including a second controller, an electrohydraulic solenoid operably connected to the bypass valve. The backup control system operable to hydraulically disable the primary control system via the bypass valve upon the occurrence of a selected condition, the second controller modulates the operation of the electrohydraulic solenoid to control the bypass actuator based on the propeller state.

Abstract: A system for controlling propeller pitch in the event of electro-hydraulic servo valve (EHSV) failure can include an actuator and a selection valve in fluid communication with the actuator. The selection valve can be fluid communication with a first EHSV having a first null state bias configured to bias the actuator to an increased-pitch position, and a second EHSV having a second null state bias configured to bias the actuator to a decreased-pitch position. The selection valve can be configured to selectively allow fluid communication between one of the first EHSV and actuator and/or the second EHSV and the actuator.

Abstract: A system for controlling propeller pitch in the event of electro-hydraulic servo valve (EHSV) failure can include an actuator and a selection valve in fluid communication with the actuator. The selection valve can be fluid communication with a first EHSV having a first null state bias configured to bias the actuator to an increased-pitch position, and a second EHSV having a second null state bias configured to bias the actuator to a decreased-pitch position. The selection valve can be configured to selectively allow fluid communication between one of the first EHSV and actuator and/or the second EHSV and the actuator.

Abstract: A system for filtering mechanically-induced signal noise from a speed sensor may include a rotating member having at least one target group radially oriented about a center of the rotating member, an inductive speed sensor configured to sense the at least one target group, and two diode pairs each having a first diode and a second diode. The two diode pairs may be operatively connected to the inductive speed sensor and configured to receive a signal having the mechanically-induced signal noise. The system may also include a resistor connecting the diode pairs, a processor connected in parallel with the resistor and configured to receive a signal from the inductive speed sensor. The processor may be configured to receive a signal having reduced signal noise via the diode pairs, and determine a rotational speed of the rotating member based on the signal having reduced signal noise.

Abstract: A system for filtering mechanically-induced signal noise from a speed sensor may include a rotating member having at least one target group radially oriented about a center of the rotating member, an inductive speed sensor configured to sense the at least one target group, and two diode pairs each having a first diode and a second diode. The two diode pairs may be operatively connected to the inductive speed sensor and configured to receive a signal having the mechanically-induced signal noise. The system may also include a resistor connecting the diode pairs, a processor connected in parallel with the resistor and configured to receive a signal from the inductive speed sensor. The processor may be configured to receive a signal having reduced signal noise via the diode pairs, and determine a rotational speed of the rotating member based on the signal having reduced signal noise.