Method and apparatus for reducing aerodynamic flutter of an aircraft wing flap

Abstract

Exemplary methods and devices for reducing aerodynamic flutter of an aircraft wing flap are disclosed. The exemplary device includes a fairing, an actuator, and a damper. The fairing is located on the underside of the aircraft wing. The actuator is disposed in the fairing. The actuator is coupled to the wing and the flap of the wing and extends between the wing and the flap of the wing. The damper is disposed in the fairing. The damper is coupled to the fixed wing and the movable flap and extends between the fixed wing and the movable flap.

Description

Technical Field

[0001] The present disclosure generally relates to aircraft wing flaps, and more particularly to methods and devices for reducing aerodynamic flutter of aircraft wing flaps. Background Art

[0002] Aircraft typically employ control surfaces (e.g., high-lift devices) along the fixed trailing edge of each wing of the aircraft. For example, each wing of the aircraft may include one or more flaps coupled to the wing, where the (one or more) flaps may be movable relative to the fixed trailing edge of the wing. During takeoff and / or landing, the (one or more) flaps may advantageously move (e.g., rotate and / or extend) in a downward and / or backward direction relative to the fixed trailing edge of the wing to change the overall shape of the wing, thereby generating more or less lift for the wing and / or the aircraft.

[0003] Movement of the (one or more) flaps relative to the fixed trailing edge of the wing is typically effected via one or more actuation mechanisms (e.g., one or more hydromechanical and / or electromechanical actuators) coupled to the (one or more) flaps and to the wing. In some known embodiments, the (one or more) flaps of the wing may experience aerodynamic flutter (e.g., vibration) in response to an operational failure of one or more of the actuation mechanisms. Without a flutter mitigation mechanism, such aerodynamic flutter can reach undesirable levels, particularly where the wings and / or flaps of the aircraft have a relatively thin construction. Summary of the Invention

[0004] Exemplary methods and devices for reducing aerodynamic flutter of aircraft wing flaps are disclosed herein. In some examples, a device is disclosed. In some disclosed examples, the device includes a fairing, an actuator, and a damper. In some disclosed examples, the fairing is located on the underside of the aircraft wing. In some disclosed examples, the actuator is disposed within the fairing. In some disclosed examples, the actuator is coupled to the wing and a flap of the wing and extends between the wing and the flap of the wing. In some disclosed examples, the damper is disposed within the fairing. In some disclosed examples, the damper is coupled to the wing and the flap and extends between the wing and the flap.

[0005] In some examples, an aircraft is disclosed. In some of the disclosed examples, the aircraft includes a wing, a fairing, an actuator, and a damper. In some of the disclosed examples, the wing has a fixed portion and a flap. In some of the disclosed examples, the flap is movable relative to the fixed portion. In some of the disclosed examples, the fairing is located on the underside of the wing. In some of the disclosed examples, the fairing extends between the fixed portion and the flap. In some of the disclosed examples, the actuator is disposed in the fairing. In some of the disclosed examples, the actuator is coupled to the fixed portion and the flap and extends between the fixed portion and the flap. In some of the disclosed examples, the damper is disposed in the fairing. In some of the disclosed examples, the damper is coupled to the fixed portion and the flap and extends between the fixed portion and the flap.

[0006] In some examples, a method is disclosed. In some of the disclosed examples, the method includes moving a flap of an aircraft wing relative to a fixed portion of the wing between a retracted position and a deployed position. In some of the disclosed examples, the flap is moved via an actuator that is coupled to the fixed portion and the flap and extends between the fixed portion and the flap. In some of the disclosed examples, the actuator is disposed in a fairing located on the underside of the wing and extends between the fixed portion and the flap. In some of the disclosed examples, the method further includes damping the movement of the flap to reduce aerodynamic flutter of the flap. In some of the disclosed examples, the movement of the flap is damped by a damper that is coupled to the fixed portion and the flap and extends between the fixed portion and the flap. In some of the disclosed examples, the damper is disposed in the fairing. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a perspective view of an example aircraft in which exemplary methods and devices for reducing aerodynamic flutter of an aircraft wing flap can be implemented in accordance with the teachings of the present disclosure.

[0008] Figure 2 is Figure 1 a first perspective view of a first exemplary wing of

[0009] Figure 3 showing the first and second exemplary flaps of the first wing in a stowed position. Figure 1 and Figure 2 a second perspective view of the first exemplary wing of

[0010] Figure 4 showing the first and second exemplary flaps of the first wing in a deployed position. Figures 1 to 3 is Figure 2 and Figure 3 a third perspective view of the first exemplary wing of

[0011] Figure 5Yes Figures 1 to 4 is a fourth perspective view of a first exemplary wing of Figures 2 to 4 wherein a first exemplary flap support fairing of

[0012] Figure 6 is shown in dashed lines. Figures 2 to 5 is a perspective view of an exemplary damper disposed in a first exemplary flap support fairing of

[0013] Figure 7 Yes Figure 6 is a rear view of an exemplary damper of Figures 2 to 6 which is disposed in a first exemplary flap support fairing of

[0014] Figure 8 Yes Figure 6 and Figure 7 is a bottom view of an exemplary damper of Figures 2 to 7 which is disposed in a first exemplary flap support fairing of

[0015] Figure 9 Yes Figures 6 to 8 is a top view of an exemplary damper of Figures 2 to 8 which is disposed in a first exemplary flap support fairing of

[0016] Figure 10 Yes Figures 6 to 9 is a perspective view of an exemplary damper of

[0017] Figure 11 Yes Figures 6 to 10 is a cross - sectional view of an exemplary damper of

[0018] Figure 12 Yes Figures 6 to 11 is a schematic view of an exemplary damper of Figure 1 which is operatively coupled to an exemplary hydraulic system of an exemplary aircraft of

[0019] Figure 13 is a cross - sectional view of another exemplary damper that can be used with the examples disclosed herein.

[0020] Figure 14 is a cross - sectional view of another exemplary damper that can be used with the examples disclosed herein.

[0021] Figure 15 is a flowchart representing an exemplary method of an exemplary damper for achieving Figures 11 to 14 during operation of an aircraft.

[0022] Certain examples are illustrated in the above - mentioned figures and described in detail below. When describing these examples, like or identical reference numerals are used to identify identical or similar elements. The figures are not necessarily drawn to scale, and for clarity and / or conciseness, certain features of the figures and certain views may be enlarged in scale or shown schematically.

[0023] When identifying multiple elements or components that can be referred to individually, the descriptors "first", "second", "third", etc. are used herein. Unless otherwise specified or understood based on their context of use, these descriptors are not intended to impart any meaning of precedence or chronological order, but are merely labels to refer to multiple elements or components separately for ease of understanding the disclosed examples. In some examples, the descriptor "first" may be used to refer to an element in the detailed description, while a different descriptor such as "second" or "third" may be used in the claims to refer to the same element. In such cases, it should be understood that such descriptors are used merely for ease of reference to multiple elements or components. Detailed Description

[0024] Aircraft typically employ control surfaces (e.g., high - lift devices) along the fixed trailing edge of each wing of the aircraft. For example, each wing of the aircraft may include one or more flaps coupled to the wing, where the (one or more) flaps are movable relative to the fixed trailing edge of the wing. During takeoff and / or landing, the (one or more) flaps may advantageously move in a downward and / or backward direction (e.g., rotate and / or extend) relative to the fixed trailing edge of the wing to change the overall shape of the wing, thereby generating more or less lift for the wing and / or the aircraft.

[0025] (The movement of the (one or more) flaps relative to the fixed trailing edge of the wing is typically effected via one or more actuation mechanisms (e.g., one or more hydromechanical and / or electromechanical actuators) coupled to the (one or more) flaps and to the wing. In some known embodiments, the (one or more) flaps of the wing may experience aerodynamic flutter (e.g., vibration) in response to an operational failure of one or more of the actuation mechanisms. Without a flutter - mitigation mechanism, such aerodynamic flutter may reach an undesirable level, particularly in cases where the wings and / or flaps of the aircraft have a relatively thin construction.

[0026] Known flutter reduction techniques include constructing flaps with higher - specification materials to increase the stiffness of the flaps. Constructing flaps with higher - specification materials requires using higher - specification materials to construct the skin and spar assemblies, which unfavorably increases the cost and weight of the aircraft. Other known flutter reduction techniques include shortening the span - wise dimension and / or the chord - wise dimension of the flaps, which can make the flaps more rigid. However, shortening the span - wise dimension and / or the chord - wise dimension of the flaps adversely affects the aerodynamic effect provided by the flaps and reduces the high - speed and / or low - speed performance of the aircraft. For example, shortening the span - wise dimension and / or the chord - wise dimension of the flaps causes an increase in drag and thus reduces the fuel efficiency of the aircraft under cruise conditions, increasing the cost of operating the aircraft. Shortening the span - wise dimension and / or the chord - wise dimension of the flaps also reduces the lift capacity of the aircraft during takeoff and landing. Thus, the aircraft may require a longer runway to take off or a higher approach speed during landing, both of which increase the cost of operating the aircraft.

[0027] Exemplary methods and devices for reducing aerodynamic flutter of an aircraft wing flap are disclosed herein. Different from the known flutter reduction techniques described above, the exemplary methods and devices disclosed herein are based on one or more dampers to reduce aerodynamic flutter of an aircraft wing flap. More specifically, the exemplary methods and devices disclosed herein implement and / or include a fairing, an actuator, and a damper. In some examples, the fairing is located on the underside of the aircraft wing. In some examples, the actuator is disposed in the fairing. In some examples, the actuator is coupled to the wing and the flap of the wing and extends between the wing and the flap of the wing, wherein the actuator is configured to move the flap between a retracted position and a deployed position relative to a fixed trailing edge of the wing. In some examples, the damper is disposed in the fairing. In some examples, the damper is coupled to the wing and the flap and extends between the wing and the flap, and the damper is configured to damp the movement of the flap to reduce aerodynamic flutter of the flap. In some examples, the damper is configured to reduce aerodynamic flutter of the flap in response to a failure of the actuator.

[0028] In some examples, a damper of an exemplary method and apparatus disclosed herein includes a piston rod having a first end and a second end opposite the first end, where the first end is coupled to a wing and the second end is coupled to a flap. In some examples, the first end of the piston rod is coupled to the wing near a fixed portion of an actuator, and the second end of the piston rod is coupled to the flap near a movable section of the actuator. In some examples, the damper includes a cylinder having a first chamber and a second chamber, and the piston rod includes a first section located within the first chamber on a first side of the rod head and a second portion located within the second chamber on a second side of the rod head, the second side being positioned opposite the first side of the rod head. To damp the movement of the flap, the rod head moves along a longitudinal axis of the cylinder to provide a damping force to the flap. In some examples, the damper is configured to move along the longitudinal axis based on pressurized hydraulic fluid supplied to the damper. For example, the damper includes an orifice configured to receive the pressurized hydraulic fluid. In some examples, the damper is configured to generate a damping force, the magnitude of which is based on the size of the orifice.

[0029] In some examples, a filter valve is coupled to a hydraulic system of an aircraft to supply pressurized hydraulic fluid to the damper. An example pressure transducer may be included to monitor the hydraulic fluid pressure of the damper. In some examples, the damper is configured to be in a passive mode when the actuator moves the flap and is also configured to be in an active mode in response to a failure of the actuator. For example, when the actuator fails, the flap can provide a threshold force to activate the damper. In some examples, a load release valve is configured to release pressure from the damper. For example, when the hydraulic pressure within the cylinder of the damper is above a threshold level, the load release valve can redirect hydraulic fluid from one or more chambers of the damper. In some examples, a cavitation-resistant valve is configured to mitigate cavitation when supplying pressurized hydraulic fluid to the damper. For example, the cavitation-resistant valve can reduce excessive noise and / or vibration due to the supply of hydraulic fluid to the damper. In some examples, the cavitation-resistant valve maintains the fluid pressure within the damper.

[0030] The examples disclosed herein reduce the cost, complexity, and weight associated with known flutter mitigation techniques and are particularly advantageous for embodiments in which the wings and / or flaps of an aircraft have a relatively thin configuration. The examples disclosed herein avoid the need to increase the thickness of the wings and flaps, thereby reducing the negative impact on aircraft performance. The examples disclosed herein avoid the need to segment trailing edge flaps, thereby reducing the addition of more weight to the aircraft (e.g., more flaps, more fairings, etc.) and reducing cost. The examples disclosed herein also avoid adding additional flap supports and actuators, thereby reducing overconstraint of flap movement and avoiding high loads at the intermediate supports of the wing. Additionally, the examples disclosed herein do not rigidly resist movement, thereby providing sufficient force to resist the oscillatory movement of the flap and reducing aerodynamic flutter.

[0031] Figure 1 is a perspective view of an exemplary aircraft 100 in which an exemplary method and apparatus for mitigating aerodynamic flutter of an aircraft wing flap may be implemented in accordance with the teachings of the present disclosure. In Figure 1 the illustrated example, the aircraft 100 includes an exemplary fuselage 102, a first exemplary wing 104 coupled to the fuselage 102, and a second exemplary wing 106 coupled to the fuselage 102. The aircraft 100 also includes a first exemplary engine 108 coupled to the first wing 104 and a second exemplary engine 110 coupled to the second wing 106. In other examples, the aircraft 100 may include a plurality of engines coupled to each of the first wing 104 and the second wing 106 and / or disposed at other locations on the aircraft 100 (e.g., coupled to the fuselage 102, coupled to the tail of the aircraft 100, etc.).

[0032] Figure 1 each of the first and second wings 104, 106 has one or more control surfaces (e.g., one or more high-lift devices) positioned along the respective fixed trailing edges of the first and second wings 104, 106. Such (one or more) control surfaces may be moved (e.g., rotated and / or extended) relative to the respective fixed trailing edges of the first and second wings 104, 106 to change the aerodynamic lift of the first and second wings 104, 106 and / or more generally the aircraft 100. In Figure 1 the illustrated example, the first wing 104 includes a first exemplary flap 112 (e.g., an inboard flap) and a second exemplary flap 114 (e.g., an outboard flap), where each of the first and second flaps 112, 114 is disposed along an exemplary fixed trailing edge 116 of the first wing 104. The first and second flaps 112, 114 may be moved downward and / or rearward (e.g., rotated and / or extended) relative to the fixed trailing edge 116 of the first wing 104 to change the shape of the first wing 104, which may be advantageous during takeoff and / or landing of the aircraft 100. InFigure 1 In the illustrated example, the second wing 106 similarly includes one or more flaps that are configured and / or operated in a manner mirroring that described above for the first flap 112 and the second flap 114 of the first wing 104. It should be understood that any disclosure related to the first wing 104 can equally apply to the second wing 106. Thus, to avoid redundancy, a description of the second wing 106 is not provided herein.

[0033] Figure 2 is Figure 1 A first perspective view of the first exemplary wing 104 of, which shows the first and second flaps 112, 114 of the first wing 104 in a retracted position. For example, during cruise, the first flap 112 and the second flap 114 are retracted to this position, which is generally better in terms of aerodynamics and fuel efficiency. Figure 3 is Figure 1 and Figure 2 A second perspective view of the first exemplary wing 104 of, which shows the first and second flaps 112, 114 of the first wing 104 in a deployed position, which is typically used during takeoff and landing to increase the chord length of the first wing 104 to generate greater lift.

[0034] To help support the first flap 112 and the second flap 114, the aircraft 100 can include a plurality of flap supports that are covered by flap support fairings. In Figure 2 and Figure 3 the illustrated example, the first wing 104 includes three flap supports (one of which is shown in more detail in conjunction with Figures 4 to 9 ) covered by three flap support fairings: a first flap support fairing 200, a second flap support fairing 202, and a third flap support fairing 204. However, any number of flap support fairings can be used (e.g., two flap support fairings on the inner flap, two flap support fairings on the outer flap). The third flap support fairing 204 (and the flap support therein) is associated with the first flap 112, and the first and second flap support fairings 200, 202 (and the corresponding flap supports therein) are associated with the second flap 114. However, in other examples, the first and second flaps 112, 114 can include more or fewer flap supports (with flap support fairings) and / or the flap supports (and flap support fairings) can be located in other positions.

[0035] As Figure 2 and Figure 3As shown between the positions in, the first flap support fairing 200 can move downward together with the second flap 114. In particular, in the example shown, the first flap support fairing 200 includes a first section 206 (e.g., a fixed section or a wing side section) covering the fixed side support of the flap support and a second section 208 (e.g., a movable section or a flap side section) covering the movable side support of the flap support. The first section 206 and the second section 208 can be considered as separate flap support fairings, which form an integral flap support fairing covering the flap support therein. In the example shown, the first section 206 of the first flap support fairing 200 is coupled to the bottom side 210 (e.g., the bottom surface) of the first wing 104, and the second section 208 of the first flap support fairing 200 is coupled to the bottom side 212 of the second flap 114. In Figure 2 the second section 208 of the first flap support fairing 200 is in an upward or stationary position (e.g., a cruise position). When the second flap 114 moves downward ( Figure 3 ), the second section 208 of the flap support fairing 200 moves downward relative to the trailing edge 116 of the first wing 104 together with the second flap 114. In Figure 2 and Figure 3 schematic examples, the second and third flap support fairings 202, 204 are substantially the same as the first flap support fairing 200.

[0036] Figure 4 is Figures 1 to 3 a third perspective view of the first exemplary wing 104, where Figure 2 and Figure 3 the first exemplary flap support fairing 200 is shown in dashed lines. In Figure 4 the illustrated example, the second flap 114 can be moved between a stowed position (as shown in Figure 2 ) and a deployed position ( Figure 3 ) by a flap actuation system 400. In the example shown, the flap actuation system 400 includes an actuator support bracket 402 (e.g., for a gear rotary actuator (GRA)), which moves a flap link arm 404 coupled to a movable side support 406 and thus coupled to the second flap 114. When actuated, the flap link arm 404 rotates the movable side support 406 downward, thereby moving the second flap 114 outward and downward from the trailing edge 116 of the first wing 104, which causes the first flap support fairing 200 to move downward together with the second flap 114. In other examples, the flap actuation system 400 can include more linkages or drive devices to move the second flap 114 between the stowed position and the extended position. The first flap support fairing 200 can be used to cover the flap actuation system 400 and / or any other (one or more) flap actuation system components to reduce drag and thus increase the fuel efficiency of the aircraft.

[0037] Figure 5 is Figures 1 to 4 a fourth perspective view of the first exemplary wing 104 of Figures 2 to 4 wherein the first exemplary flap support fairing 200 of

[0038] Figure 6 is disposed in Figures 2 to 5 a perspective view of an exemplary damper 600 in the first exemplary flap support fairing 200 of

[0039] During operation, the flap link arm 404 rotates the movable side support 406 downward, causing the second flap 114 to move outward and downward from the trailing edge 116 of the first wing 104. During cruise (e.g., when the aircraft 100 is in flight), the flap link arm 404 rotates the movable side support 406 upward, causing the second flap 114 to move inward and upward from the trailing edge 116 of the first wing 104 to a retracted (e.g., stowed) position. In some examples, the flap link arm 404 may not be able to maintain the load on the second flap 114, exposing the second flap 114 to aerodynamic flutter. To mitigate aerodynamic flutter when the flap link arm 404 cannot maintain the load on the second flap 114, the damper 600 engages the second flap 114 to hold the load on the second flap 114, as discussed in more detail below.

[0040] Figure 7 is Figure 6 a rear view of the exemplary damper 600 of Figures 2 to 6 disposed in the first exemplary flap support fairing 200 of

[0041] Figure 8 is Figure 6 and Figure 7Bottom view of an exemplary damper 600, which is disposed in Figures 2 to 7 the first exemplary flap support fairing 200 of

[0042] Figure 9 is Figures 6 to 8 Top view of an exemplary damper 600, which is disposed in Figures 2 to 8 the first exemplary flap support fairing 200 of

[0043] Figure 10 is Figures 6 to 9 Perspective view of an exemplary damper 600. In the illustrated example, the damper 600 includes a housing 1000, a cylinder 1002, a tube 1004, a connector 1006, a first rod end 1008, and a second rod end 1010. In some examples, the first rod end 1008 is coupled to the wing 104 via a first side support 602 near a fixed portion of the flap actuation system 400 (e.g., support bracket 402), and the second rod end 1010 is coupled to a second flap 114 via a second side support 604 near a movable portion of the flap actuation system 400 (e.g., flap link arm 404 and / or movable side support 406). In some examples, the housing 1000 is coupled to the wing 104 via a first side support 602 near a fixed portion of the flap actuation system 400 (e.g., support bracket 402), and the second rod end 1010 is coupled to the second flap 114 via a second side support 604 near a movable portion of the flap actuation system 400 (e.g., flap link arm 404 and / or movable side support 406). In the illustrated example, the housing 1000 has a length 1012, a width 1014, and a height 1016. In some examples, the dimensions of the length 1012, width 1014, and height 1016 may be set to dispose the damper 600 within a flap support fairing (e.g., flap support fairing 200). In some examples, the length 1012, width 1014, and height 1016 may be sized based on an expected amount of aerodynamic flutter. That is, the dimensions of the housing 1000 may be determined based on the required amount of hydraulic fluid. In some examples, the dimensions of the housing 1000 may be determined based on a number of components (e.g., pipes, sensors, valves, etc.) to be disposed within the housing 1000. In the illustrated example, the tube 1004 (e.g., via welding) is coupled to the housing 1000 and the connector 1006. In the illustrated example, the connector 1006 is coupled to the cylinder 1002. In this way, the tube 1004 and the connector 1006 fluidly couple the housing 1000 to the cylinder 1002, as discussed in more detail below. In the illustrated example, the housing 1000 includes an inlet 1018 to receive hydraulic fluid from an aircraft 100 (e.g., the hydraulic fluid system of the aircraft 100).

[0044] Figure 11 isFigures 6 to 10 Cross-sectional view of an exemplary damper 600. In the example shown, the damper 600 includes a first chamber 1100, a second chamber 1102, a rod 1104, a rod head 1106, a first gland retainer 1108, a first gland 1110, a second gland retainer 1112, and a second gland 1114. In the example shown, the rod 1104 (e.g., a piston rod) is coupled to the second rod end 1010. In the example shown, the cylinder 1002 includes the first chamber 1100 and the second chamber 1102. In the example shown, the rod 1104 includes a first segment 1116 located within the first gland retainer 1108 and the first chamber 1100 on a first side 1118 of the rod head 1106, and a second portion 1120 located within the second chamber 1102 on a second side 1122 of the rod head, the second side 1122 being oppositely positioned to the first side 1118 of the rod head 1106. In the example shown, the housing 1000 includes a fluid chamber 1124, a first outlet 1126, and a second outlet 1128. In the example shown, the fluid chamber 1124 is to receive the hydraulic fluid discharge from the aircraft 100 (e.g., the hydraulic fluid system of the aircraft 100) via the inlet 1018. The fluid chamber 1124 of the illustrative example supplies the hydraulic fluid (e.g., through an orifice) to the second chamber 1102 on the first side 1118 of the rod head 1106 via the first outlet 1126 via the first fluid supply line 1130. To supply the hydraulic fluid to the second side 1122 of the rod head 1106 in the second chamber 1102, the fluid chamber 1124 includes a second outlet 1128, and the second outlet 1128 couples the second fluid supply line 1132 to the second side 1122 of the rod head 1106 in the second chamber 1102 via the tube 1004 and the connector 1006. In the example shown, the fluid chamber 1124 is shown coupled to the exemplary component 1134 via the third fluid supply line 1136 to the hydraulic system of the aircraft 100. In the example shown, the first fluid supply line 1130, the second fluid supply line 1132, and the third fluid supply line 1136 are made of a flexible material to accommodate the movement of the damper 600. In some examples, the first fluid supply line 1130, the second fluid supply line 1132, and the third fluid supply line 1136 are made of a rigid material. In combination with Figure 12 Component 1134 is described in more detail.

[0045] To damp the movement of the second flap 114 when the flap actuation system 400 is inoperative, the rod head 1106 moves along the longitudinal axis 1138 of the cylinder 1002 to push hydraulic fluid through the orifice 1202 to provide a damping force to the second flap 114. In some examples, the rod head 1106 moves along the longitudinal axis 1138 based on pressurized hydraulic fluid supplied to the second chamber 1102 via the fluid chamber 1124. For example, when the second end 1010 moves along the longitudinal axis 1138, when the rod head 1106 moves toward the second gland 1114, the hydraulic fluid can flow from the second chamber 1102 on the second side 1122 of the rod head 1106 (e.g., through the orifice 1202) through the first fluid supply line 1130 to the first side 1118 of the rod head 1106 through the second fluid supply line 1132. In an illustrative example, the first gland 1110 and the second gland 1114 maintain a seal within the cylinder 1002. That is, the first gland 1110 and the second gland 1114 hold the hydraulic fluid within the cylinder 1002 (e.g., within the second chamber 1102). In some examples, the rod head 1106 may include an orifice. That is, when the rod head 1106 moves along the longitudinal axis 1138, the hydraulic fluid can flow from the first side 1118 of the rod head 1106 in the second chamber 1102 to the second side 1122 of the rod head 1106 in the second chamber 1102 through the rod head 1106.

[0046] Figure 12 is Figures 6 to 11 a schematic illustration of an exemplary damper 600 that is operably coupled to Figure 1 an exemplary hydraulic system 1200 of an exemplary aircraft 100. Figure 12 Shows Figure 10 and 11Component 1134 of housing 1000. In the example shown, housing 1000 (e.g., damper 600) includes orifice 1202, filter valve 1204, first pressure transducer 1206, second pressure transducer 1208, first pressure limiter 1210, second pressure limiter 1212, first safety check valve 1214, second safety check valve 1216, first anti-cavitation valve 1218, second anti-cavitation valve 1220, load relief valve 1222, and flight control electronic unit (FCEU) 1224. In other examples, first pressure limiter 1210 and second pressure limiter 1212 may be omitted from housing 1000 and / or damper 600. In the example shown, filter valve 1204 filters hydraulic fluid from hydraulic system 1200 of aircraft 100. For example, filter valve 1204 filters debris from the hydraulic fluid before it reaches orifice 1202. In the example shown, damper 600 is configured to produce a damping force having a magnitude based on the size of orifice 1202 and the rate at which hydraulic fluid is pushed through orifice 1202. For example, the size of orifice 1202 may be based on an expected magnitude of aerodynamic flutter. In some examples, orifice 1202 may have a diameter of approximately 0.01 to 0.2 inches. However, the diameter of orifice 1202 may be less than or greater than the approximate range of aerodynamic flutter based on the expected magnitude. In some examples, the size of orifice 1202 may be set to provide an excessive damping force. That is, the size of orifice 1202 may be set to over-damp (e.g., provide a greater damping force than necessary) based on the expected magnitude of aerodynamic flutter.

[0047] In the example shown, the first pressure transducer 1206, the first pressure limiter 1210, the first safety check valve 1214, and the first anti-cavitation valve 1218 are fluidly coupled to the first side 1118 of the rod head 1106 in the second chamber 1102, and the second pressure transducer 1208, the second pressure limiter 1212, the second safety check valve 1216, and the second anti-cavitation valve 1220 are fluidly coupled to the second side 1122 of the rod head 1106 in the second chamber 1102. The first pressure transducer 1206 and the second pressure transducer 1208 monitor the hydraulic fluid pressure in the second chamber 1102 of the damper 600. In some examples, the first pressure transducer 1206 and the second pressure transducer 1208 generate electrical signals based on the pressure measured at the orifice 1202 and / or within the second chamber 1102. In some examples, during normal aircraft operation, the first pressure transducer 1206 and the second pressure transducer 1208 monitor the pressure in the second chamber 1102 and output signals to notify the flight crew that the damper 600 is not operating properly. In some examples, the first safety check valve 1214 and the second safety check valve 1216 can open when the pressure within the second chamber 1102 exceeds the thresholds of the first pressure transducer 1206 and the second pressure transducer 1208 and the thresholds of the first pressure limiter 1210 and the second pressure limiter 1212. For example, the pressure within the second chamber 1102 can exceed the pressure threshold of the first pressure limiter 1210 (e.g., the pressure at which the first pressure limiter 1210 can no longer limit the pressure), and the first safety check valve 1214 can open and redirect the hydraulic fluid to the load relief valve 1222. The load relief valve 1222 of the example shown redirects the hydraulic fluid to the filter valve 1204 when the hydraulic fluid expands due to high temperature and / or if the orifice 1202 is blocked by debris. The filter valve 1204 is configured to act as a relief valve to relieve any excessive pressure from the damper 600. In the example shown, the first and second anti-cavitation valves 1218, 1220 are configured to mitigate cavitation when pressurized hydraulic fluid is supplied to the second chamber 1102 of the damper 600. For example, the first anti-cavitation valve 1218 reduces the formation of bubbles and reduces excessive noise and / or vibration generated by supplying hydraulic fluid to the damper 600.

[0048] In the example shown, the FCEU 1224 is operably coupled to (e.g., in communication with) the first pressure transducer 1206 and the second pressure transducer 1208. The FCEU 1224 can send and / or receive data from the first pressure transducer 1206 and the second pressure transducer 1208 to determine whether the damper 600 is operating properly, whether the damper 600 has failed, and / or whether the damper 600 is actively mitigating aerodynamic flutter.

[0049] In some examples, damper 600 is configured to be in a passive mode when actuator 402 moves second flap 114. For example, damper 600 provides a minimal force (e.g., a drag force less than 20 pounds) on second flap 114 when actuator 402 moves second flap 114 between the deployed position and the retracted position. In some examples, damper 600 is configured to be in an active mode in response to a failure of actuator 402. For example, when actuator 402 fails, second flap 114 can provide a threshold force to second rod end 1010 to actuate damper 600, thereby reducing aerodynamic flutter.

[0050] As used herein, the term "passive mode" refers to an operating state in which the actuator operates normally (e.g., the actuator is actuating a flap) when hydraulic fluid passes through an orifice between a first side 1118 of rod head 1106 in second chamber 1102 and a second side 1122 of rod head 1106 in second chamber 1102, and the damper provides a negligible resistance (e.g., a drag force less than 20 pounds). As used herein, the term "active mode" refers to an operating state in which the damper provides a damping force (e.g., a drag force greater than 20 pounds) to reduce aerodynamic flutter when hydraulic fluid passes through an orifice between a first side 1118 of rod head 1106 in second chamber 1102 and a second side 1122 of rod head 1106 in second chamber 1102.

[0051] Figure 13 is a cross-sectional view of another exemplary damper 1300 that can be used with the examples disclosed herein. In Figure 13 the illustrated example, damper 1300 operates in a manner similar to Figure 11 damper 600. However, contrary to Figure 11 damper 600, the housing 1000 of this damper 1300 is separated from cylinder 1002. That is, the housing 1000 of damper 1300 can be coupled to a fixed wing portion of aircraft 100, which is separate from the coupler of first ends 1008 and 1010. In some examples, the housing 1000 of damper 1300 can be located at a position other than inside a fairing (e.g., fairing 200).

[0052] Figure 14 is a cross-sectional view of another exemplary damper 1400 that can be used with the examples disclosed herein. In Figure 14 the illustrated example, damper 1400 operates in a manner similar to Figure 11 damper 600 and Figure 13 damper 1300. However, contrary to Figure 11 damper 600 and Figure 13In contrast to damper 1300, damper 1400 includes an exemplary linear variable differential transducer (LVDT) 1402. LVDT 1402 includes a body 1404 and a core 1406 within a rod 1104 on a first side 1118 of the rod head 1106. In the illustrated example, the body 1404 is coupled to the first end 1008 and the core 1406 is coupled to the rod head 1106. Thus, for example, when the rod 1104 moves along the longitudinal axis 1138, the core 1406 moves within the body 1404 to measure displacement. LVDT 1402 senses, measures, and / or detects Figure 14 the position of the rod 1104 (e.g., retracted position, extended position, etc.). In some examples, LVDT 1402 is operatively coupled to (e.g., communicates with) a remote electronic unit (REU) 1408 such that the REU 1408 can receive and / or obtain damper position feedback data sensed, measured, and / or detected via the LVDT 1402. In the illustrated example, positioning the LVDT 1402 within the rod 1104 allows the REU 1408 and / or the FCEU 1224 to determine whether the damper 1400 is actively damping the flap. Additionally, positioning the LVDT 1402 within the rod 1104 eliminates the need for an external sensor to measure the flap position. Thus, positioning the LVDT 1402 within the rod 1104 reduces the need for external sensors and the brackets and linkages associated with the external sensors, thereby reducing cost and weight.

[0053] Figure 15 is a flow chart depicting an exemplary method 1500 for implementing exemplary dampers 600, 1300, 1400 during operation of an aircraft. Method 1500 begins by obtaining measurements from a pressure transducer (block 1502). For example, the FCEU 1224 (or the REU 1408) obtains measurements from the first pressure transducer 1206 and the second pressure transducer 1208.

[0054] At block 1504, it is determined whether the absolute value is greater than a threshold. For example, the FCEU 1224 determines whether the absolute value of the pressure difference between (i) the pressure on the first side 1118 of the rod head 1106 in the second chamber 1102 and (ii) the pressure on the second side 1122 of the rod head 1106 in the second chamber 1102 is greater than a threshold. In some examples, the threshold depends on the size of the orifice 1202 and the flow rate of the hydraulic fluid. If the FCEU 1224 determines that the absolute value is not greater than the threshold, method 1500 proceeds to block 1506 and the FCEU 1224 does not send a message. Then, method 1500 ends.

[0055] If the FCEU 1224 determines that the absolute value is greater than the threshold, the method 1500 proceeds to block 1508, and the FCEU 1224 sends a message to request an inspection. For example, the FCEU 1224 sends a message to request an inspection of the actuator 402 and the damper 600 after landing.

[0056] At block 1510, the FCEU 1224 determines whether the structure is intact. For example, the FCEU determines whether the pressure difference is high because the damper 600 is mitigating aerodynamic flutter and moving at a faster rate than normal. If the FCEU 1224 determines that the structure is not intact, the method 1500 proceeds to block 1512, and the FCEU 1224 sends a message to repair / replace the structure (e.g., the damper, the actuator, etc.). Then, the method 1500 ends.

[0057] If the FCEU 1224 determines that the structure is intact, the method 1500 proceeds to block 1514, and the FCEU 1224 sends a message to inspect the damper and repair / replace it as needed. Then, the method 1500 ends.

[0058] In view of the foregoing, it will be appreciated that the methods and devices disclosed above mitigate aerodynamic flutter. The examples disclosed herein reduce the cost, complexity, and weight associated with known flutter mitigation techniques and are particularly advantageous for embodiments in which the wings and / or flaps of an aircraft have a relatively thin configuration. The examples disclosed herein avoid the need to increase the thickness of the wings and flaps, thereby mitigating the negative impact on aircraft performance. The examples disclosed herein avoid the need to segment the trailing edge flaps, thereby mitigating the addition of more weight (e.g., more flaps, more fairings, etc.) to the aircraft and reducing costs. The examples disclosed herein also avoid adding additional flap supports and actuators, thereby mitigating overconstraint of flap movement and avoiding high loads at the intermediate supports of the wings. Additionally, the examples disclosed herein do not rigidly resist movement, thereby providing sufficient force to resist the oscillatory movement of the flaps and reducing aerodynamic flutter.

[0059] In some examples, a device is disclosed. In some of the disclosed examples, the device includes a fairing, an actuator, and a damper. In some of the disclosed examples, the fairing is located on the underside of an aircraft wing. In some of the disclosed examples, the actuator is disposed within the fairing. In some of the disclosed examples, the actuator is coupled to the wing and the flap of the wing and extends between the wing and the flap of the wing. In some of the disclosed examples, the damper is disposed within the fairing. In some of the disclosed examples, the damper is coupled to the wing and the flap and extends between the wing and the flap.

[0060] In some disclosed examples, the actuator is configured to move the flap between a retracted position and a deployed position relative to the fixed trailing edge of the wing. In some disclosed examples, the damper is configured to damp the movement of the flap to reduce aeroelastic flutter of the flap.

[0061] In some disclosed examples, the damper is configured to reduce aeroelastic flutter of the flap in response to a failure of the actuator.

[0062] In some disclosed examples, the damper is configured to reduce aeroelastic flutter of the flap when the flap is in the retracted position.

[0063] In some disclosed examples, the damper includes a piston rod having a first end and a second end opposite the first end. In some disclosed examples, the first end is coupled to the wing and the second end is coupled to the flap.

[0064] In some disclosed examples, the first end of the piston rod is coupled to the wing near a fixed portion of the actuator. In some disclosed examples, the second end of the piston rod is coupled to the flap near a movable portion of the actuator.

[0065] In some disclosed examples, the damper includes a cylinder having a first chamber and a second chamber. In some disclosed examples, the piston rod includes a first portion located within the first chamber on a first side of the piston head of the piston rod and a second portion located within the second chamber on a second side of the piston head of the piston rod, the second side being located opposite the first side of the piston head.

[0066] In some disclosed examples, the piston head is movable along a longitudinal axis of the cylinder to provide a damping force to the flap. In some disclosed examples, the damper is configured to move along the longitudinal axis based on pressurized hydraulic fluid to be supplied to the damper.

[0067] In some disclosed examples, the damper includes an orifice configured to receive pressurized hydraulic fluid. In some disclosed examples, the damper is configured to generate a damping force, the magnitude of which is based on the size of the orifice.

[0068] In some disclosed examples, the device further includes a filter valve and a pressure transducer. In some disclosed examples, the filter valve is coupled to the hydraulic system of the aircraft. In some disclosed examples, the filter valve is configured to supply pressurized hydraulic fluid to the damper. In some disclosed examples, the pressure transducer is configured to monitor the hydraulic fluid pressure of the damper.

[0069] In some disclosed examples, the damper is configured to be in a passive mode when the actuator moves the flap. In some disclosed examples, the damper is configured to be in an active mode in response to a failure of the actuator.

[0070] In some disclosed examples, the device further includes a load release valve configured to release pressure from the damper.

[0071] In some disclosed examples, the device further includes a cavitation valve configured to reduce cavitation when supplying pressurized hydraulic fluid to the damper.

[0072] In some examples, an aircraft is disclosed. In some disclosed examples, the aircraft includes a wing, a fairing, an actuator, and a damper. In some disclosed examples, the wing has a fixed portion and a flap. In some disclosed examples, the flap is movable relative to the fixed portion. In some disclosed examples, the fairing is located on the underside of the wing. In some disclosed examples, the fairing extends between the fixed portion and the flap. In some disclosed examples, the actuator is disposed in the fairing. In some disclosed examples, the actuator is coupled to the fixed portion and the flap and extends between the fixed portion and the flap. In some disclosed examples, the damper is disposed in the fairing. In some disclosed examples, the damper is coupled to the fixed portion and the flap and extends between the fixed portion and the flap.

[0073] In some disclosed examples, the actuator is configured to move the flap between a retracted position and a deployed position relative to the fixed trailing edge of the wing. In some disclosed examples, the damper is configured to damp the movement of the flap to reduce aeroelastic flutter of the flap.

[0074] In some disclosed examples, the damper is configured to reduce aeroelastic flutter of the flap in response to a failure of the actuator.

[0075] In some disclosed examples, the damper is configured to reduce aeroelastic flutter of the flap when the flap is in the retracted position.

[0076] In some examples, a method is disclosed. In some disclosed examples, the method includes moving a flap of an aircraft wing between a retracted position and a deployed position relative to a fixed portion of the wing. In some disclosed examples, the flap is moved via an actuator coupled to the fixed portion and the flap and extending between the fixed portion and the flap. In some disclosed examples, the actuator is disposed in a fairing located on the underside of the wing and extends between the fixed portion and the flap. In some disclosed examples, the method further includes damping the movement of the flap to reduce aeroelastic flutter of the flap. In some disclosed examples, the movement of the flap is damped by a damper coupled to the fixed portion and the flap and extending between the fixed portion and the flap. In some disclosed examples, the damper is disposed in the fairing.

[0077] In some disclosed examples, damping of the movement of the flap occurs in response to a failure of the actuator.

[0078] In some disclosed examples, damping of the movement of the flap occurs when the flap is in the retracted position.

[0079] Although certain exemplary methods, devices, and articles have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, devices, and manufactured articles that fall entirely within the scope of the claims of this patent.

[0080] Clause 1: A device, comprising a fairing (200) located on the underside (210) of a wing (104) of an aircraft (100); an actuator (400) disposed within the fairing, the actuator being coupled to the wing and a flap (114) of the wing and extending between the wing and the flap of the wing; and a damper (600, 1300, 1400) disposed within the fairing, the damper being coupled to the wing and the flap and extending between the wing and the flap.

[0081] Clause 2: The device according to Clause 1, wherein the actuator is configured to move the flap between a retracted position and a deployed position relative to a fixed trailing edge (116) of the wing, and the damper is configured to damp the movement of the flap to reduce aerodynamic flutter of the flap.

[0082] Clause 3: The device according to Clause 2, wherein the damper is configured to reduce aerodynamic flutter of the flap in response to a failure of the actuator.

[0083] Clause 4: The device according to Clause 2, wherein the damper is configured to reduce aerodynamic flutter of the flap when the flap is in the retracted position.

[0084] Clause 5: The device according to any one of Clauses 1 to 4, wherein the damper includes a piston rod (1104) having a first end (1008) and a second end (1010) positioned opposite the first end, the first end being coupled to the wing and the second end being coupled to the flap.

[0085] Clause 6: The device according to Clause 5, wherein the first end of the piston rod is coupled to the wing near a fixed portion of the actuator, and the second end of the piston rod is coupled to the flap near a movable portion of the actuator.

[0086] Clause 7: The device according to Clause 5, wherein the damper includes a cylinder (1002) having a first chamber (1100) and a second chamber (1102), and wherein the piston rod includes a first portion (1116) located within the first chamber on a first side (1118) of a rod head (1106) of the piston rod and a second portion (1120) located within the second chamber on a second side (1122) of the rod head, the second side being positioned opposite the first side of the rod head.

[0087] Clause 8: The apparatus according to Clause 7, wherein the club head is movable along a longitudinal axis (1138) of the cylinder to provide a damping force to the flap, and the damper is configured to move along the longitudinal axis based on pressurized hydraulic fluid supplied to the damper.

[0088] Clause 9: The apparatus according to any one of Clauses 1 to 8, wherein the damper includes an orifice (1202) configured to receive pressurized hydraulic fluid, and the damper is configured to generate a damping force having a measure based on the size of the orifice.

[0089] Clause 10: The apparatus according to any one of Clauses 1 to 9, further comprising: a filter valve (1204) coupled to a hydraulic system (1200) of the aircraft, the filter valve being configured to supply pressurized hydraulic fluid to the damper, and pressure transducers (1206, 1208) configured to monitor a hydraulic fluid level of the damper.

[0090] Clause 11: The apparatus according to Clause 10, wherein the damper is configured to be in a passive mode when the actuator moves the flap, and wherein the damper is configured to be in an active mode in response to a failure of the actuator.

[0091] Clause 12: The apparatus according to Clause 10, further comprising a load release valve (1222) configured to release pressure from the damper.

[0092] Clause 13: The apparatus according to Clause 10, further comprising cavitation resistant valves (1218, 1220) configured to reduce cavitation when supplying pressurized hydraulic fluid to the damper.

[0093] Clause 14: An aircraft (100) comprising a wing (104) having a fixed portion and a flap (114), the flap being movable relative to the fixed portion; a fairing (200) located on a bottom side (210) of the wing, the fairing extending between the fixed portion and the flap; an actuator (400) disposed in the fairing, the actuator being coupled to the fixed portion and the flap and extending between the fixed portion and the flap, and a damper (600, 1300, 1400) disposed in the fairing, the damper being coupled to the fixed portion and the flap and extending between the fixed portion and the flap.

[0094] Clause 15: The aircraft according to Clause 14, wherein the actuator is configured to move the flap between a retracted position and a deployed position relative to a fixed trailing edge (116) of the wing, and the damper is configured to damp the movement of the flap to reduce aerodynamic flutter of the flap.

[0095] Clause 16: The aircraft according to Clause 15, wherein the damper is configured to mitigate aerodynamic flutter of the flap in response to a failure of the actuator.

[0096] Clause 17: The aircraft according to Clause 15, wherein the damper is configured to mitigate aerodynamic flutter of the flap when the flap is in the retracted position.

[0097] Clause 18: A method comprising moving a flap (114) of a wing (104) of an aircraft (100) between a retracted position and a deployed position relative to a fixed portion of the wing, the flap being moved by an actuator (400) coupled to the fixed portion and the flap and extending between the fixed portion and the flap, the actuator being disposed in a fairing (200) located on a bottom side (210) of the wing and extending between the fixed portion and the flap; and damping the movement of the flap to mitigate aerodynamic flutter of the flap, the movement of the flap being damped by a damper (600, 1300, 1400) coupled to the fixed portion and the flap and extending between the fixed portion and the flap, the damper being disposed in the fairing.

[0098] Clause 19: The method according to Clause 18, wherein damping of the movement of the flap occurs in response to a failure of the actuator.

[0099] Clause 20: The method according to Clause 18, wherein damping of the movement of the flap occurs when the flap is in the retracted position.

Claims

1. An aircraft (100) comprising: A fairing (200) located on the underside (210) of a wing (104) of the aircraft (100); An actuator (400) disposed in the fairing, the actuator being coupled to the wing and a flap (114) of the wing and extending between the wing and the flap; And Dampers (600, 1300, 1400) provided in the fairing, the dampers being coupled to the wing and the flap and extending between the wing and the flap, Wherein the damper (600, 1300, 1400) comprises: A piston rod (1104) having a first end (1008) and a second end (1010) opposite the first end (1008), the first end (1008) being coupled to the wing and the second end (1010) being coupled to the flap: A first gland retainer (1108), a first gland (1110), a second gland retainer (1112) and a second gland (1114); A cylinder (1002) having a first chamber (1100) and a second chamber (1102), and wherein the piston rod (1104) includes a first portion (1116) located within the first gland retainer (1108) and the first chamber on a first side (1118) of a rod head (1106) of the piston rod (1104) and a second portion (1120) located within the second chamber (1102) on a second side (1122) of the rod head (1106) located opposite the first side of the rod head (1106), wherein the first gland (1110) and the second gland (1114) are configured to maintain a seal within the cylinder (1002) to retain hydraulic fluid within the second chamber (1102), and wherein the rod head (1106) is within the second chamber (1102); and A housing (1000) including a fluid chamber (1124), a first outlet (1126) and a second outlet (1128), wherein the fluid chamber (1124) is configured to supply pressurized hydraulic fluid to the second chamber (1102): (a) via the first outlet (1126) via a first fluid supply line (1130) on the first side (1118) of the rod head (1106); and (b) via a second fluid supply line (1132) on the second side (1122) of the rod head (1106), wherein the second outlet (1128) couples the second fluid supply line (1132) to the second chamber (1102) via a tube (1004) and a connector (1006); Wherein when the club head (1106) moves towards the second gland (1114), the hydraulic fluid is configured to flow from the second chamber (1102) on the second side (1122) of the club head (1106) through the first fluid supply line (1130) to the first side (1118) of the club head (1106) via the second fluid supply line (1132); Wherein the housing (1000) includes a first pressure transducer (1206), a first safety check valve (1214) and a first anti-cavitation valve (1218) fluidly coupled to the first side (1118) of the club head (1106) in the second chamber (1102); a second pressure transducer (1208), a second safety check valve (1216) and a second anti-cavitation valve (1220) fluidly coupled to the second side (1122) of the club head (1106) in the second chamber (1102), wherein the first pressure transducer (1206) and the second pressure transducer (1208) are configured to monitor the hydraulic fluid pressure in the second chamber (1102) of the damper (600); Wherein the first safety check valve (1214) and the second safety check valve (1216) are configured to open when the pressure in the second chamber (1102) exceeds the thresholds of the first pressure transducer (1206) and the second pressure transducer (1208) and the thresholds of the first pressure limiter (1210) and the second pressure limiter (1212); Wherein the first anti-cavitation valve (1218) and the second anti-cavitation valve (1220) are configured to mitigate cavitation when the pressurized hydraulic fluid is supplied to the damper; and Wherein the housing further includes: a load release valve (1222) configured to release pressure from the damper, a flight control electronic unit (1224), and a filter valve (1204) configured to filter the hydraulic fluid from the hydraulic system (1200) of the aircraft (100).

2. The aircraft (100) according to claim 1, wherein the pressure thresholds of the first pressure limiter (1210) and the second pressure limiter (1212) are the pressures at which the first pressure limiter (1210) and the second pressure limiter (1212) can no longer limit the pressure in the second chamber (1102).

3. The aircraft (100) according to claim 1 or 2, wherein the first safety check valve (1214) and the second safety check valve (1216) are further configured to redirect the hydraulic fluid to the load release valve (1222).

4. The aircraft (100) according to claim 1 or 2, wherein the flight control electronic unit (1224) is operably coupled to the first pressure transducer (1206) and the second pressure transducer (1208).

5. The aircraft (100) according to claim 4, wherein the flight control electronic unit (1224) is configured to transmit and / or receive data from the first pressure transducer (1206) and the second pressure transducer (1208) to determine whether the damper (600) is operating properly, whether the damper (600) has failed, and / or whether the damper (600) is actively reducing aerodynamic flutter.

6. The aircraft (100) according to claim 1 or 2, wherein, The actuator is configured to move the flap relative to the fixed trailing edge (116) of the wing between a retracted position and a deployed position, and the damper is configured to damp the movement of the flap to reduce aerodynamic flutter of the flap.

7. The aircraft (100) according to claim 6, wherein, The damper is configured to (a) reduce aerodynamic flutter of the flap in response to a failure of the actuator.

8. The aircraft (100) according to claim 6, wherein the damper is configured to reduce aerodynamic flutter of the flap when the flap is in the retracted position.

9. An aircraft (100) according to any one of claims 1, 2, 5, 7 or 8, wherein, The first end of the piston rod is coupled to the wing near the fixed portion of the actuator, and the second end of the piston rod is coupled to the flap near the movable portion of the actuator.

10. The aircraft (100) according to any one of claims 1, 2, 5, 7, or 8, wherein the rod head is movable along the longitudinal axis of the cylinder to provide a damping force to the flap, and the damper is configured to move along the longitudinal axis based on pressurized hydraulic fluid supplied to the damper.

11. The aircraft (100) according to any one of claims 1, 2, 5, 7, or 8, wherein the damper is configured to generate a damping force having a magnitude based on the size of a damping orifice.

12. An aircraft (100) according to any one of claims 1, 2, 5, 7 or 8, wherein, The damper is configured to be in a passive mode when the actuator is moving the flap, and wherein the damper is configured to be in an active mode in response to a failure of the actuator.

13. The aircraft (100) according to any one of claims 1, 2, 5, 7, or 8, wherein the fluid chamber (1124) is configured to receive the pressurized hydraulic fluid from a hydraulic fluid system of the aircraft (100) via an inlet (1018).

14. A method of reducing aerodynamic flutter of an aircraft wing flap, comprising: moving a flap (114) of a wing (104) of an aircraft (100) between a retracted position and a deployed position relative to a fixed portion of the wing, the flap being moved via an actuator (400) that is coupled to the fixed portion and the flap and extends between the fixed portion and the flap, the actuator being disposed in a fairing (200) located on a bottom side (210) of the wing and extending between the fixed portion and the flap; and damping the movement of the flap to reduce aerodynamic flutter of the flap, the movement of the flap being damped by a damper (600, 1300, 1400) that is coupled to the fixed portion and the flap and extends between the fixed portion and the flap, the damper being disposed in the fairing. Wherein the damper (600, 1300, 1400) comprises: A piston rod (1104) having a first end (1008) and a second end (1010) opposite the first end (1008), the first end being coupled to the wing and the second end being coupled to the flap: A first gland retainer (1108), a first gland (1110), a second gland retainer (1112) and a second gland (1114); A cylinder (1002) having a first chamber (1100) and a second chamber (1102), and wherein the piston rod (1104) includes a first portion (1116) located within the first gland retainer (1108) and the first chamber on a first side (1118) of a rod head (1106) of the piston rod (1104), and a second portion (1120) located within the second chamber (1102) on a second side (1122) of the rod head (1106) opposite the first side of the rod head (1106), wherein the first gland (1110) and the second gland (1114) are configured to maintain a seal within the cylinder (1002) to retain hydraulic fluid within the second chamber (1102), and wherein the rod head (1106) is within the second chamber (1102); A housing (1000) including a fluid chamber (1124), a first outlet (1126) and a second outlet (1128), wherein the fluid chamber (1124) is configured to supply pressurized hydraulic fluid to the second chamber (1102): (a) via the first outlet (1126) via a first fluid supply line (1130) on the first side (1118) of the rod head (1106); (b) via a second fluid supply line (1132) on the second side (1122) of the rod head (1106), wherein the second outlet (1128) couples the second fluid supply line (1132) to the second chamber (1102) via a tube (1004) and a connector (1006); Wherein when the rod head (1106) moves towards the second gland (1114), the hydraulic fluid is configured to flow from the second chamber (1102) on the second side (1122) of the rod head (1106) through the first fluid supply line (1130) to the first side (1118) of the rod head (1106) through the second fluid supply line (1132); The housing (1000) includes a first pressure transducer (1206), a first safety check valve (1214), and a first anti-cavitation valve (1218) fluidly coupled to the first side (1118) of the rod head (1106) in the second chamber (1102); a second pressure transducer (1208), a second safety check valve (1216), and a second anti-cavitation valve (1220) fluidly coupled to the second side (1122) of the rod head (1106) in the second chamber (1102), wherein the first pressure transducer (1206) and the second pressure transducer (1208) are configured to monitor the hydraulic fluid pressure in the second chamber (1102) of the damper (600); The first safety check valve (1214) and the second safety check valve (1216) are configured to open when the pressure in the second chamber (1102) exceeds the thresholds of the first pressure transducer (1206) and the second pressure transducer (1208) and the thresholds of a first pressure limiter (1210) and a second pressure limiter (1212); The first anti-cavitation valve (1218) and the second anti-cavitation valve (1220) are configured to mitigate cavitation when the pressurized hydraulic fluid is supplied to the damper; and The housing (1000) further includes: a load release valve (1222) configured to release pressure from the damper, a flight control electronic unit (1224), and a filter valve (1204) configured to filter the hydraulic fluid from the hydraulic system (1200) of the aircraft (100).

15. The method for reducing aerodynamic flutter of an aircraft wing flap according to claim 14, wherein, In response to a failure of the actuator, damping of the movement of the flap occurs.

16. A method for reducing aerodynamic flutter of an aircraft wing flap according to claim 14 or 15, wherein, Damping of the flap occurs when the flap is in the retracted position.

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