A turbomachinery engine can include a fan assembly with a plurality of variable pitch fan blades. The fan blades are configured such that they define a first VPF parameter and a second VPF parameter. The first VPF parameter is within a range of 0.10 to 0.40 and is defined as the hub-to-tip radius ratio divided by the fan pressure ratio. The second VPF parameter is within a range of 1-30 lbf/in.sup.2 and is defined as the bearing spanwise force divided by the fan area. In certain examples, the turbomachinery engine further includes a pitch change mechanism, a vane assembly, a core engine, and a gearbox.

A hydraulic control circuit of a steering actuator having a first and a second chamber, for orienting the blades of an aircraft engine propeller, this circuit comprising a high-pressure line and a low-pressure line, a first protection valve being able to assume a deactivated position or an activated position for placing the first chamber in communication with the high-pressure line, a second protection valve being able to assume a deactivated position or an activated position for placing the second chamber in communication with the low-pressure line, each protection valve comprising a hydraulic activation inlet and a hydraulic deactivation inlet which can be pressurised in order to activate or deactivate these valves. The circuit includes a solenoid protection valve controlling an amplification valve connected to the inlets of the protection valves in order to activate them upon the activation of the solenoid protection valve.

Systems and methods are provided to control a rotor blade pitch. In one example, a system comprises a ratchet mechanism comprising a ratchet wheel configured to be rotated by a motor about a first axis. The ratchet mechanism comprises one or more followers each of which is coupled to the ratchet wheel. The ratchet wheel rotates the one or more followers in a first direction about the first axis when the ratchet wheel is rotated by the motor in the first direction about the first axis. One or more rotor blades rotate about the first axis. Each rotor blade is affixed to a respective follower. Each follower controls a pitch of the respective rotor blade based on a position of the follower relative to the ratchet wheel.

A gas turbine engine includes a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order. A fan defining a fan axis and comprising a plurality of fan blades is rotatable about the fan axis. A pitch change mechanism is operable with the plurality of fan blades to control a pitch of the plurality of fan blades. A counterweight is connected to each respective fan blade. A spring mechanism is operably associated with each fan blade of the plurality of fan blades to create a spring twisting moment on the respective fan blade that is counter to a centrifugal twisting moment of the respective fan blade.

A gas turbine engine including a frame, a plurality of fan blades configured to rotate about a longitudinal centerline axis of the gas turbine engine, and a mounting assembly coupling the frame to a structure. The gas turbine engine includes a sensor assembly coupled to the mounting assembly and having at least one sensor configured to detect a loading on the mounting assembly and to take a corrective action when propeller whirl is detected above a predetermined limit, and a feature configured to take a corrective action when propeller whirl is detected above a predetermined limit.