Abstract: A linear actuator is provided. The linear actuator comprises: a body; a shaft adapted to move linearly relative to the body; a driver adapted to drive the linear movement of the shaft; and a shape memory alloy component configured to compensate for thermal expansion or contraction of the linear actuator due to a change in temperature thereof.

Abstract: An actuator rod assembly for a blade pitch control system is provided herein. The actuator rod assembly includes a tubular outer rod and an inner rod. The outer rod has a first end and a second end. The inner rod has a first end and a second end and extends through the tubular outer rod. The inner rod is tensioned against the tubular outer rod so as to place the outer rod in compression.

Abstract: A rotary seal comprises a seal element comprising a disc-shaped body having a first axial side and an opposed second axial side. The seal element further comprises a radially inner central circular opening for receiving a rotary shaft, the opening having an inner periphery for sealing engagement with the shaft. A radially outer rim portion of the seal element comprises an axially facing annular sealing surface provided on the first axial side for sealing engagement in use with an opposed axially facing sealing surface of an adjacent first static housing and an axially facing pocket provided on the second axial side and having an axially facing surface for receiving, in use, an annular elastomeric biasing element. At least one drainage passage is formed through the outer rim portion from an inlet on the second axial side to an outlet on a radially outer portion of the rim portion.

Abstract: A spool valve arrangement comprising a spool arranged for linear movement within a bore to regulate flow of fluid through the bore according to the linear position of the spool relative to the bore, the spool having an end arranged to be engaged, in use, by a drive member to cause the linear movement, the spool valve arrangement further comprising a sliding block component moveably attached to the spool end and arranged to engage with the drive member, in use, such that the drive member engages with the spool end via the sliding block component and the sliding block component moves relative to the spool to compensate for non-linear movement of the drive member.

Abstract: A gurney flap arrangement includes: an airfoil 2 with a trailing edge 6 and an opening 14 in a surface 8 of the airfoil 2; a gurney flap 1 having a first position in which at least a portion of the gurney flap 1 extends through the opening 14 and projects outwardly from the airfoil surface 8, and a second position in which the gurney flap 1 does not project from the airfoil surface 8 or projects outwardly from the airfoil surface 8 to a lesser extent; and a gurney flap actuator 3 for moving the gurney flap 1 between at least the first position and the second position.

Abstract: A hydraulic damper comprises an outer cylinder, and an inner cylinder slidably mounted within the outer cylinder for movement relative to the outer cylinder along a longitudinal axis. The inner cylinder has a circumferential wall circumscribing a bellows assembly. The bellows assembly comprises a first bellows section, a second bellows section, a damping plate attached to and separating the first and second bellows sections, a first closure element closing an end of the first bellows section opposite the damping plate to define a first chamber, and a second closure element closing an end of the second bellows section opposite the damping plate to define a second chamber. The first closure element is attached to the inner cylinder for movement therewith relative to the outer cylinder. The second closure element is also attached to the inner cylinder for movement therewith relative to the outer cylinder.

Abstract: A gurney flap arrangement comprises: an airfoil with an opening in a surface of the airfoil; a gurney flap having a first position in which at least a portion of the gurney flap extends through the opening and projects outwardly from the airfoil surface, and a second position in which the gurney flap does not project from the airfoil surface or projects outwardly from the airfoil surface to a lesser extent; and a seal disposed about the opening to seal a gap in the opening between the gurney flap and the airfoil.

Abstract: A hydraulic spool valve assembly comprising a housing defining a bore having a longitudinal axis (L), a hydraulic spool valve, a sleeve disposed within the bore and a temperature compensation device disposed between the sleeve and the housing. The hydraulic spool valve having a first end for connection to a drive arm, and an opposing second end disposed within the bore. The sleeve disposed between the hydraulic spool valve and the housing. The temperature compensation device configured to expand in a first longitudinal direction in response to a temperature increase, to oppose movement of the sleeve in an opposing second longitudinal direction caused by the temperature increase.

Abstract: A drive lever comprising a first end for insertion into a slot of the hydraulic spool valve. The first end comprises at least two resilient members which resist radial compression (R1, R2) such that they exert a radially outward force (F1, F2) on one or more inner surfaces of the slot when inserted therein. This radially outward force (F1, F2) can account for any backlash that would otherwise be present between the drive lever and the slot due to manufacturing tolerances or wear.

Abstract: A load bearing assembly comprises: a lug body; an outer race disposed within and supported by the lug body; an inner race disposed within and supported by the outer race; and a relief slot defined between the adjacent surfaces of the outer race and the lug body, wherein the relief slot is formed in the surface of the outer race.

Abstract: The present disclosure relates to an adjustment system a method for compensating for temperature variations in a spool valve. The spool valve and adjustment system may be parts in a duplex hydraulic actuator. The adjustment device comprises a spring, a pivot point, and a shape memory alloy (SMA) device. The spring and SMA device are disposed on either side of the pivot point to hold the pivot point in a first position. The SMA device is configured to change size in response to a temperature change so as move the pivot point to a second location. This may eliminate force fight in the duplex hydraulic actuator by preventing asynchronous activation of the spool valves due to thermal expansion within the spool valves.