Various mechanisms for adjusting pitches of propeller blades are described. For example, the pitch adjustment mechanism may include a propeller hub enclosing a geared mechanism that cooperates with a compound gearbox having first and second planetary stages to adjust pitches of propeller blades. Alternatively, the pitch adjustment mechanism may include a propeller hub enclosing a pitch adjustment assembly that utilizes tension cables and torsion springs, or rack-and-pinion structures, to adjust pitches of propeller blades. Using any of the various mechanisms, the pitches of propeller blades may be rotated at least 90 degrees, and up to and exceeding 360 degrees, in order to effect thrust reversals and/or adjust thrust profiles.

Various mechanisms for adjusting pitches of propeller blades are described. For example, the pitch adjustment mechanism may include a propeller hub enclosing a geared mechanism that cooperates with a compound gearbox having first and second planetary stages to adjust pitches of propeller blades. Alternatively, the pitch adjustment mechanism may include a propeller hub enclosing a pitch adjustment assembly that utilizes tension cables and torsion springs, or rack-and-pinion structures, to adjust pitches of propeller blades. Using any of the various mechanisms, the pitches of propeller blades may be rotated at least 90 degrees, and up to and exceeding 360 degrees, in order to effect thrust reversals and/or adjust thrust profiles.

A central-positioned pitch control device used in a coaxial helicopter includes an upper propeller hub; a lower propeller hub; a first blade mounted on the outside of the upper propeller hub; a second blade mounted on the outside of the lower propeller hub; and a central-positioned pitch control device placed between the upper propeller hub and the lower propeller hub.

A central-positioned pitch control device used in a coaxial helicopter includes an upper propeller hub; a lower propeller hub; a first blade mounted on the outside of the upper propeller hub; a second blade mounted on the outside of the lower propeller hub; and a central-positioned pitch control device placed between the upper propeller hub and the lower propeller hub.

An adaptive flight control system for controlling the pitch of blades of a propulsive propeller of a hybrid helicopter as a function of the return value of the pitch. The adaptive flight control system comprises control means supplying the pitch control order, a piloting member controlling variation of the pitch, and piloting means applying a control gain in order to transform the control order into a setpoint, and transmitting the setpoint to the piloting member. The piloting means include information return means applying a return gain that is variable to the return value of the variation of the pitch to the piloting means, also modifying the control gain as a function of the return value.

An adaptive flight control system for controlling the pitch of blades of a propulsive propeller of a hybrid helicopter as a function of the return value of the pitch. The adaptive flight control system comprises control means supplying the pitch control order, a piloting member controlling variation of the pitch, and piloting means applying a control gain in order to transform the control order into a setpoint, and transmitting the setpoint to the piloting member. The piloting means include information return means applying a return gain that is variable to the return value of the variation of the pitch to the piloting means, also modifying the control gain as a function of the return value.

A gas turbine engine including: a turbomachine having 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 rotatable about the fan axis; and a pitch change mechanism operable with the plurality of fan blades, the pitch change mechanism including a plurality of linkages, the plurality of linkages including a first linkage coupled to a first fan blade of the plurality of fan blades and a second linkage coupled to a second fan blade of the plurality of fan blades; and a non-uniform blade actuator system operable with one or more of the plurality of linkages to control a pitch of the first fan blade relative to a pitch of the second fan blade.

A blade pitch adjustment system comprising a yoke arranged to be moved in a first direction in response to an actuator; a plurality of trunnion pins arranged to be attached to a respective propeller blade; a respective contact surface between the yoke and each trunnion pin such that movement of the yoke causes rotation of the blades, and wherein the contact surfaces differ so as to create different angles of rotation of the blades at different points of yoke movement or actuator stroke.

A blade pitch adjustment system comprising a yoke arranged to be moved in a first direction in response to an actuator; a plurality of trunnion pins arranged to be attached to a respective propeller blade; a respective contact surface between the yoke and each trunnion pin such that movement of the yoke causes rotation of the blades, and wherein the contact surfaces differ so as to create different angles of rotation of the blades at different points of yoke movement or actuator stroke.

A control system for controlling the pitch of a propeller, the system including a propeller shaft, a blade swivel device having a rotary control element suitable for placing the blades in an angular position corresponding to a desired propeller pitch, and a transmission presenting an outlet member coupled in rotation with the rotary control element of the blade swivel device. The transmission includes a variable speed drive having drive, control, and outlet rotors that are coupled in rotation respectively with the propeller shaft, with a control member, and with the outlet member of the transmission. With the variable speed drive, the speed of rotation of the outlet member of the transmission is a predetermined function of the speeds of rotation not only of the propeller shaft, but also of the control member.