Abstract: The pitch of either a fan or propeller driven by a gas turbine engine is changed by utilizing a pair of impulse turbines interfacing between the stationary and rotating portion of the fan or propeller and utilizing a servo control responding to a desired pitch input signal for actuating the normally inactive impulse turbines during fixed pitch to drive the impulse turbine which in turn is operatively connected through a pitch change actuator to change the pitch in accordance with the input signal.

Abstract: An arrangement for the adjusting of rotor blades of a propfan turboprop engine equipped with two counter-rotating propfan rotors has a number of double-toothed planet wheels which are fastened in a rotatably disposed web. The web is supported on the side of the housing by planet members disposed on one of the propfan rotors. The two toothings of the planet wheels are in operative connection with ball spindle adjusting rings. Using an adjusting motor, a relative movement of the web can be achieved with respect to the housing, whereby the blades of two counter-rotating rotor blade rings can be swivelled. According to the invention, an adjustment of rotor blades will also be possible when no stationary housing parts are available for the support.

Abstract: A hydraulic device for the individual control of the pitch of a helicopter rotor blade by a rotary hydraulic jack, the stator vanes of which are integral with a sleeve fitted on the hub. The jack rotor carries rotor vanes movable relative to the stator vanes and delimiting with these chambers of variable volume fed by a servo-distributor controlled as a function of pilot signals and signals from a detector of the angular position of the blade about its pitch axis. The jack is integrated in a pitch bearing and in an elastic ball joint integrated in a rotary hydroelastic shock absorber with vanes for lamination of a viscous fluid. The shock-absorber rotor is connected rigidly in terms of rotation about the pitch axis to the rotor of the jack and is connected to the blade by a rigid cuff.

Abstract: A rotary actuator, suitable for use with rotors having flow-varying blading, for effecting adjustment of the blading, including two relatively-rotatable and co-axially-disposed main actuator components. Each of the components carries a respective abutment means, one of which is axially-displaceable with respect to its component between an inoperative position and an operative position, and both of which are so disposed with respect to their components that during operation of the actuator with said one abutment means in its operative position, the two abutment means co-operate to arrest relative rotational movement of said components only upon said components reaching a pre-determined relative rotational position.

Abstract: A rotary actuator includes two relatively-rotatable main actuator components, abutment means being carried by the first component and displaceable axially with respect thereto, and further abutment means being carried by the second component. Holding means is operable for holding the displaceable abutment means out of engagement with respect to the further abutment means whereby relative rotational movement between the components occurs when one of them moves in either one of its two directions of rotation. Controlling means is operative, with the holding means inoperative, for urging the displaceable abutment means into engagement with the further abutment means at any relative rotational position of the components.

Abstract: A bladed rotor including a hub which carries, so as to be rotatable therewith, a liquid reservoir, at least one pump operable upon rotation of the rotor, a single liquid-pressure-operable vane-type actuator for adjusting the blades of the rotor to vary flow of fluid over the blades, and control valve means for controlling operation of the actuator. The said pump, when operating, draws liquid from the reservoir and delivers it under pressure, by way of said control valve means, to said actuator.