Electronic propeller control system

A system for controlling the blade angle of a plurality of blades of a propeller, said system comprising:

• an actuator for adjusting the blade angle of the plurality of blades in response to hydraulic pressure;
• a servo valve disposed in selective fluid communication with said actuator, said servo valve providing hydraulic pressure to said actuator in response to a control signal;
• an electronic control providing the control signal to actuate said servo valve in response to a plurality of input signals;
• a protection valve disposed in fluid communication with and intermediate said servo valve and said actuator, said protection valve selectively providing fluid communication between said servo valve and said actuator in response to a protect pressure;
• and
• a backup device in fluid communication with said protection valve, said backup device providing a protect pressure to actuate said protection valve in response to a predetermined condition;
• wherein said backup device includes a feather valve for providing a protect pressure to actuate said protection valve to rotate the plurality of blades to a feathered position, and
• wherein said backup device further includes a lever assembly for actuating said feather valve in response to the predetermined condition.

A system for controlling the blade angle of a plurality of blades of a propeller, said system comprising:

• an actuator for adjusting the blade angle of the plurality of blades in response to hydraulic pressure;
• a servo valve disposed in selective fluid communication with said actuator, said servo valve providing hydraulic pressure to said actuator in response to a control signal;
• an electronic control providing the control signal to actuate said servo valve in response to a plurality of input signals;
• a protection valve disposed in fluid communication with and intermediate said servo valve and said actuator, said protection valve selectively providing fluid communication between said servo valve and said actuator in response to a protect pressure;
• and
• a backup device in fluid communication with said protection valve, said backup device providing a protect pressure to actuate said protection valve in response to a predetermined condition;
• wherein said backup device includes a negative torque valve for providing a protect pressure to actuate said protection valve to rotate the plurality of blades to a feathered position;
• wherein said negative torque valve includes a plunger that actuates the torque valve in response to a negative torque fault condition;
• wherein said backup device includes a proximate switch that provides a signal to the electronic control indicative of the position of the plunger;
• and
• wherein said backup device further includes a disarm valve disposed in fluid communication and intermediate the negative torque valve and said protection valve to disable the function of the negative torque valve.