Abstract: An actuation system for a control surface for an aircraft includes a first, second, third and fourth actuator, a first and second bell crank, and at least one push pull rod system. Each of the first and second bell cranks comprises a first and a second crank arm, the first and second crank arms intersect with and are joined to each other at an intersection, the first and second crank arms extend from the intersection at an angle to each other, the first bell crank is pivotally connected to the sub-structure by a first pivot extending through the first bell crank's intersection, and the second bell crank is pivotally connected to the sub-structure by a second pivot extending through the second bell crank's intersection.

Abstract: An abradable seal includes an outer ring arrangement and an energiser for urging said outer ring arrangement against an opposing surface, wherein an outermost surface of said outer ring arrangement defines a sealing surface of said abradable seal; wherein said outer ring arrangement is configured such that after a first period of operation said sealing surface suddenly transitions from having a relatively large surface area to having a relatively small surface area, so as to cause a sudden increase in internal leakage across the seal at said transition.

Abstract: An actuation system for a control surface for an aircraft includes a first, second, third and fourth actuator, a first and second bell crank, and at least one push pull rod system. Each of the first and second bell cranks comprises a first and a second crank arm, the first and second crank arms intersect with and are joined to each other at an intersection, the first and second crank arms extend from the intersection at an angle to each other, the first bell crank is pivotally connected to the sub-structure by a first pivot extending through the first bell crank's intersection, and the second bell crank is pivotally connected to the sub-structure by a second pivot extending through the second bell crank's intersection.

Abstract: A rotor for an electrical machine comprises a rotor body having an external, axially extending magnet receiving surface for receiving at least one magnet thereon, and a flange mounting portion at at least one axial end of the magnet receiving surface. The flange mounting portion has a smaller external dimension (D1) than an external dimension (D2) of the magnet receiving surface so as to form a shoulder between the magnet receiving surface and the flange mounting portion. A magnet retaining flange is mounted over the flange mounting portion of the rotor body and located against the shoulder. The magnet retaining flange is retained against the shoulder by at least one lip of the flange mounting portion of the rotor body which extends radially outwardly over a radially inner portion of the magnet retaining flange. The lip by deforming an end face of the flange mounting portion.

Abstract: An abradable seal includes an outer ring arrangement and an energiser for urging said outer ring arrangement against an opposing surface, wherein an outermost surface of said outer ring arrangement defines a sealing surface of said abradable seal; wherein said outer ring arrangement is configured such that after a first period of operation said sealing surface suddenly transitions from having a relatively large surface area to having a relatively small surface area, so as to cause a sudden increase in internal leakage across the seal at said transition.

Abstract: An abradable seal is provided, comprising an outer ring arrangement and an energiser for urging said outer ring arrangement against an opposing surface, wherein an outermost surface of said outer ring arrangement defines a sealing surface of said abradable seal; wherein said outer ring arrangement is configured such that after a first period of operation said sealing surface suddenly transitions from having a relatively large surface area to having a relatively small surface area, so as to cause a sudden increase in internal leakage across the seal at said transition.

Abstract: An actuator control arrangement is provided comprising a pair of rotary control valves used in combination to control the operation of an actuator. The rotary control valves are driven synchronously through a hydraulic or mechanical coupling. Each rotary control valve has a by-pass mode which activates in the event of a jam. In addition each rotary control valve has a mechanism for activating the by-pass mode absent any jam. The actuator control arrangement further comprises a circuit coupling a pilot control and/or a flight control computer (FCC) to one or both of the mechanisms for remotely switching the rotary control valve(s) from an active mode to a by-pass mode under control of a pilot or FCC.

Abstract: A rotor for an electrical machine comprises a rotor body having an external, axially extending magnet receiving surface for receiving at least one magnet thereon, and a flange mounting portion at at least one axial end of the magnet receiving surface. The flange mounting portion has a smaller external dimension (D1) than an external dimension (D2) of the magnet receiving surface so as to form a shoulder between the magnet receiving surface and the flange mounting portion. A magnet retaining flange is mounted over the flange mounting portion of the rotor body and located against the shoulder. The magnet retaining flange is retained against the shoulder by at least one lip of the flange mounting portion of the rotor body which extends radially outwardly over a radially inner portion of the magnet retaining flange. The lip by deforming an end face of the flange mounting portion.

Abstract: There is disclosed a method of monitoring the health of an abradable seal located on a piston of an actuator, the method comprising the steps of: (i) measuring an initial velocity of said actuator piston while said actuator is maintained in a passive condition at an initial time; (ii) operating said actuator; (iii) measuring a subsequent velocity of said actuator piston while said actuator is maintained in a passive condition at a subsequent time; (iv) repeating steps (ii)-(iii) and either: recording or outputting the measured subsequent velocities over time; or determining a health status of said actuator when said subsequent velocity has increased above a predetermined amount.

Abstract: An actuator control arrangement is provided comprising a pair of rotary control valves used in combination to control the operation of an actuator. The rotary control valves are driven synchronously through a hydraulic or mechanical coupling. Each rotary control valve has a by-pass mode which activates in the event of a jam. In addition each rotary control valve has a mechanism for activating the by-pass mode absent any jam. The actuator control arrangement further comprises a circuit coupling a pilot control and/or a flight control computer (FCC) to one or both of the mechanisms for remotely switching the rotary control valve(s) from an active mode to a by-pass mode under control of a pilot or FCC.

Abstract: A sealing arrangement for an actuator, said sealing arrangement comprising: a sealing surface; and two or more seal recesses for receiving seals, said two or more seal recesses provided at the sealing surface of the sealing arrangement.

Abstract: An abradable seal is provided, comprising an outer ring arrangement and an energiser for urging said outer ring arrangement against an opposing surface, wherein an outermost surface of said outer ring arrangement defines a sealing surface of said abradable seal; wherein said outer ring arrangement is configured such that after a first period of operation said sealing surface suddenly transitions from having a relatively large surface area to having a relatively small surface area, so as to cause a sudden increase in internal leakage across the seal at said transition.

Abstract: There is disclosed a method of monitoring the health of an abradable seal located on a piston of an actuator, the method comprising the steps of: (i) measuring an initial velocity of said actuator piston while said actuator is maintained in a passive condition at an initial time; (ii) operating said actuator; (iii) measuring a subsequent velocity of said actuator piston while said actuator is maintained in a passive condition at a subsequent time; (iv) repeating steps (ii)-(iii) and either: recording or outputting the measured subsequent velocities over time; or determining a health status of said actuator when said subsequent velocity has increased above a predetermined amount.