Patent Description:
An aircraft may include several control surfaces configured to affect the yaw, roll, and pitch of the aircraft during flight. Such control surfaces may include, for example, ailerons to affect the roll about a longitudinal axis, a rudder to affect the yaw about a vertical axis and an elevator to affect the pitch about a lateral axis, each axis being with respect to a coordinate system fixed to the aircraft. Additional control surfaces include trailing edge flaps configured to affect the lift of a wing, leading edge slats configured to affect the stall speed of a wing, and spoilers, which are generally located adjacent to and forward of the trailing edge flaps and are configured to disrupt the airflow over a wing surface to reduce lift or to increase drag. Current spoilers are airfoil-like components that include a metal honeycomb core sandwiched between two metal skins with sidewalls (also referred to as "closeouts") fastened about the honeycomb core to the close the area between the skins. The honeycomb core and closeouts are typically machined to match the airfoil shape of the spoiler. Machining these parts tends to increase manufacturing times and material waste. <CIT> discloses an arrangement of the prior art.

A control surface for an aircraft is disclosed herein. In accordance with aspects of the invention, a control surface is provided according to claim <NUM>.

In various optional embodiments, the core further includes a core mounting flange located at the leading edge. In various optional embodiments, the outer skin comprises an outer skin mounting flange. The outer skin mounting flange is coupled to the core mounting flange.

In various optional embodiments, an inner skin is coupled to the plurality of grooves. In various optional embodiments, the core includes a plurality of closeout flanges extending between the plurality of ridges and the plurality of grooves and between the inner skin and the outer skin.

In various optional embodiments, the outer skin and the core each comprises a fiber reinforced thermoplastic composite material.

A method of forming a control surface is also disclosed herein. In accordance with aspects of the invention, a method is provided according to claim <NUM>.

In various optional embodiments, the thermoplastic panel and the outer skin each comprises a fiber reinforced thermoplastic composite material.

In various optional embodiments, the step of coupling the corrugated core to the outer skin comprises heating at least one of the outer skin or the corrugated core such that a matrix material of the fiber reinforced thermoplastic composite material of the corrugated core crosslinks with a matrix material of the fiber reinforced thermoplastic composite material of the outer skin.

In various optional embodiments, the method further comprises the steps of forming an inner skin comprising the fiber reinforced thermoplastic composite material, locating the corrugated core between the inner skin and the outer skin, and coupling the corrugated core to the inner skin by heating at least one of the inner skin or the corrugated core such that the matrix material of the fiber reinforced thermoplastic composite material of the corrugated core crosslinks with a matrix material of the fiber reinforced thermoplastic composite material of the inner skin.

In various optional embodiments, the step of forming the thermoplastic panel into the corrugated core comprises forming a mounting flange at a leading edge of the corrugated core.

In various optional embodiments, the step of forming the thermoplastic panel into the corrugated core comprises forming a plurality of first closeout flanges over an outboard end of the control surface; and forming a plurality of second closeout flanges over an inboard end of the control surface.

In various optional embodiments, the method further comprises the step of coupling the outer skin and the corrugated core to an aerostructure such that the corrugated core is adjacent to the aerostructure.

In various optional embodiments, the step of forming the thermoplastic panel into the corrugated core comprises forming the plurality of ridges having a decreased pitch proximate a trailing edge.

An aerostructure is also disclosed herein. In accordance aspects of the invention, an aerostructure is provided according to claim <NUM>.

In various optional embodiments, the plurality of corrugations includes a plurality of ridges and a plurality of grooves, and the outer skin terminates at a leading edge ridge of the plurality of ridges.

In various optional embodiments, the core includes a core mounting flange and the outer skin includes an outer skin mounting flange. The outer skin mounting flange is coupled to the core mounting flange, and the aerostructure further comprises a mount coupled to the outer skin mounting flange and the core mounting flange.

In various optional embodiments, the core is adjacent to the aerostructure surface.

Referring now to the drawings, <FIG> illustrates an aircraft <NUM> having a variety of control surfaces disposed on/about the wings <NUM> and the tail section <NUM> of the aircraft <NUM>. <FIG> illustrates a wing <NUM> having a plurality of spoilers <NUM> disposed along an upper surface <NUM> of the wing <NUM>, with each of the plurality of spoilers <NUM> illustrated in a deployed position. Referring specifically to <FIG>, the variety of control surfaces typically used on the wings <NUM> of the aircraft <NUM> may include, for example, a spoiler <NUM>, an aileron <NUM>, a trailing edge flap <NUM>, and a leading edge slat <NUM>. Spoiler <NUM> is disposed adjacent to and forward of the trailing edge flap <NUM>. The variety of control surfaces typically used on the tail section <NUM> of the aircraft <NUM> may include, for example, a rudder <NUM> and an elevator <NUM>.

While the foregoing description of the variety of control surfaces generally refers to each control surface as a single component, it will be appreciated that, in various embodiments, each individual component (e.g., spoiler <NUM>) may be a single component within a plurality of like components (e.g., a plurality of spoilers <NUM>), as illustrated in <FIG>. For example, with reference to <FIG>, the plurality of spoilers <NUM> may, in various embodiments, include a first spoiler <NUM>, a second spoiler <NUM>, and a third spoiler <NUM>. In various embodiments, each one of the plurality of spoilers <NUM> includes an upper surface <NUM> and a lower surface <NUM> opposite the upper surface <NUM>, a trailing edge <NUM>, a leading edge <NUM>, an inboard (or first) end <NUM>, and an outboard (or second) end <NUM>. One or more spoiler mounts (e.g., fasteners) <NUM> may be used to secure spoilers <NUM> to the aerostructure (e.g., the wing <NUM>). In various embodiments, spoiler mounts <NUM> may be located along the leading edge <NUM> of spoilers <NUM> and may secure spoilers <NUM> to wing <NUM>. While details and examples are included herein pertaining to spoilers, such as, for example, one of the plurality of spoilers <NUM> just described, the present disclosure is not necessarily so limited, and thus aspects of the disclosed embodiments may be adapted for performance in a variety of other control surfaces, such as, for example, aileron <NUM>, trailing edge flap <NUM>, rudder <NUM>, and/or elevator <NUM> as described above.

Referring now to <FIG> and <FIG>, various aspects of a spoiler <NUM>, described above with reference to <FIG>, are illustrated. In accordance with various embodiments, spoiler <NUM> includes an outer (or first) skin <NUM>, an inner (or second) skin <NUM>, and a core <NUM>. Outer skin <NUM> may form upper surface <NUM> of spoiler <NUM>. Inner skin <NUM> may form lower surface <NUM>. In this regard, when in the deployed position (as shown <FIG>), outer skin <NUM> and upper surface <NUM> are oriented generally in the forward direction, while inner skin <NUM> and lower surface <NUM> are oriented generally aft. In the stowed position, inner skin <NUM> and lower surface <NUM> are oriented toward wing <NUM> (<FIG>), while outer skin <NUM> and upper surface <NUM> are oriented (e.g., face) away from wing <NUM>. Outer skin <NUM> may form leading edge <NUM>.

Outer skin <NUM> and inner skin <NUM> may be formed of continuous fiber reinforced thermoplastic composite materials, such as, for example, polyaryletherketone (PAEK) combinations that exhibit high-temperature stability and high mechanical strength. Such materials also include polyether ether ketone (PEEK) and polyetherketoneketone (PEKK). In this regard, outer skin <NUM> and inner skin <NUM> are formed of a material that includes fibers (e.g., carbon and/or glass fibers) surrounded by a thermoplastic (e.g., PAEK, PEEK PEKK) matrix.

In accordance with various embodiments, core <NUM> is located between outer skin <NUM> and inner skin <NUM>. Core <NUM> may extend between and contact outer skin <NUM> and inner skin <NUM>. As described in further detail below, core <NUM> may be coupled to outer skin <NUM> and inner skin <NUM>. Core <NUM> may extend from inboard end <NUM> to outboard end <NUM> of spoiler <NUM>. Core <NUM> may be formed of continuous fiber reinforced thermoplastic composite material, such as, for example, PAEK, PEEK, PEKK. In this regard, core <NUM> is formed of a material that includes fibers (e.g., carbon and/or glass fibers) surrounded by a thermoplastic (e.g., PAEK, PEEK PEKK) matrix.

<FIG> illustrates core <NUM>. With combined reference to <FIG> and <FIG> and 2B, in accordance with various embodiments, core <NUM> comprises a plurality of corrugations <NUM> (e.g., core <NUM> is a corrugated core). For example, core <NUM> may be heated until the fiber reinforced thermoplastic composite material becomes pliable. Once pliable, the material is corrugated or otherwise shaped (e.g., folded, shaped over a mold tool, etc.) to the desired core shape. In accordance with various embodiments, core <NUM> may be a continuous piece of material that is corrugated. Core <NUM> has a height H. Height H of core <NUM> decreases in a direction extending from leading edge <NUM> to trailing edge <NUM>. Corrugations <NUM> (also referred to as folded corrugations) include a plurality of ridges (or outer apexes) <NUM> located at outer skin <NUM> and a plurality of grooves (or inner apexes) <NUM> located at inner skin <NUM>. Walls <NUM> of core <NUM> extend between ridges <NUM> and grooves <NUM>. In various embodiments, ridges <NUM>, grooves <NUM>, and walls <NUM> may extend from inboard end <NUM> to outboard end <NUM>. While <FIG> illustrates ridges <NUM>, grooves <NUM>, and walls <NUM> as having a generally straight shape (e.g., ridges <NUM>, grooves <NUM>, and walls <NUM> form generally straight, planar, and/or flat structures between inboard end <NUM> and outboard end <NUM>), it is contemplated that ridges <NUM> and/or grooves <NUM> and/or walls <NUM> may be formed in other shapes.

For example, and with reference to <FIG>, in various embodiments, corrugations <NUM> may be formed in a zig-zag pattern between inboard end <NUM> and outboard end <NUM>. In this regard, ridges <NUM>, grooves <NUM>, and the walls <NUM> extending between each ridge <NUM> and groove <NUM> may include a plurality of angled portions (e.g., portions that are oriented at angles other than <NUM>° relative to on another). The straight configuration of corrugations <NUM> of core <NUM> in <FIG> and the zig-zag configuration of corrugations <NUM> of core <NUM> in <FIG> are exemplary. It is contemplated and understood that ridges <NUM> and/or grooves <NUM> and/or walls <NUM> of core <NUM> may be formed having any desired shape - e.g., curved, polygonal, multi-angle, etc. shaped portions - extending between inboard end <NUM> and outboard end <NUM>.

With combined reference to <FIG> and <FIG> and <FIG>, in accordance with various embodiments, the height H of walls <NUM> (i.e., the distance between each ridge <NUM> and its adjacent groove <NUM>) deceases in a direction extending from leading edge <NUM> to trailing edge <NUM>. In this regard, a height H of a leading edge ridge <NUM>LE may be greater than the height H of ridges <NUM> located closer to trailing edge <NUM>. In various embodiments, a pitch P of ridges <NUM> may decrease closer to trailing edge <NUM> (e.g., the pitch P may progressively decrease proceeding in the direction of the trailing edge <NUM>). The pitch P of ridges <NUM> is the distance between adjacent ridges <NUM>. In this regard, the pitch of the ridges <NUM> proximate trailing edge may be less than the pitch P of the ridges <NUM> proximate leading edge <NUM>. The decreased pitch of ridges <NUM> proximate trailing edge <NUM> tends to increase the strength of spoiler <NUM> at trailing edge <NUM> due to the increased density of the core <NUM> near trailing edge <NUM>.

In various embodiments, core <NUM> includes a core mounting flange <NUM>. Core mounting flange <NUM> may extend from a leading edge wall <NUM>LE of core <NUM>. Core mounting flange <NUM> may be oriented at an angle θ of between <NUM>° and <NUM>°, between <NUM>° and <NUM>°, and/or between <NUM>° and <NUM>° relative to leading edge wall <NUM>LE of core <NUM>. In various embodiments, angle θ may be approximately <NUM>°. In the previous context only, "approximately" means ±<NUM>°. Core mounting flange <NUM> may be located between an outer skin mounting flange <NUM> of outer skin <NUM> and an inner skin mounting flange <NUM> of inner skin <NUM>. Core mounting flange <NUM> may be coupled to outer skin mounting flange <NUM> and inner skin mounting flange <NUM>.

Core mounting flange <NUM>, outer skin mounting flange <NUM>, and inner skin mounting flange <NUM> (collectively "mounting flanges <NUM>, <NUM>, <NUM>") may be located at leading edge <NUM> of spoiler <NUM>. In various embodiments, mounting flanges <NUM>, <NUM>, <NUM> may be employed to secure the spoiler <NUM> to an aerostructure (e.g., wing <NUM>). Stated differently, spoiler <NUM> may be attached to the aerostructure (e.g., wing <NUM>) by coupling spoiler mounts <NUM> to mounting flanges <NUM>, <NUM>, <NUM>. Coupling core mounting flange <NUM> to outer skin <NUM> and inner skin <NUM> tends to increase the bond strength between core <NUM> and outer and inner skins <NUM>, <NUM>, by increasing the contact area between core <NUM> and outer and inner skins <NUM>, <NUM>. Core mounting flange <NUM> may be coupled to outer skin mounting flange <NUM> and inner skin mounting flange <NUM> by heating outer skin <NUM> and/or of inner skin <NUM> and/or core <NUM> such that the thermoplastic matrix of outer skin <NUM> and inner skin crosslinks (e.g., polymerizes) with the thermoplastic matrix of core <NUM>.

With reference to <FIG>, in various embodiments, outer skin mounting flange <NUM> may be coupled directly to inner skin mounting flange <NUM>. In other words, in various embodiments, core <NUM> may not include core mounting flange <NUM>. Outer skin mounting flange <NUM> may be coupled to inner skin mounting flange <NUM> by heating outer skin <NUM> and/or of inner skin <NUM> such that the thermoplastic matrix of outer skin <NUM> crosslinks (e.g., polymerizes) with the thermoplastic matrix of inner skin <NUM>.

With reference to <FIG>, in various embodiments, core <NUM> may form leading edge <NUM> of spoiler <NUM>. In this regard, outer skin <NUM> may terminate at the leading edge ridge <NUM>LE of core <NUM>. Leading edge ridge <NUM>LE is the ridge <NUM> that is closest to the leading edge <NUM> of spoiler <NUM>. Stated differently, outer skin <NUM> may include a first end <NUM>, which is coupled to core <NUM> and inner skin <NUM> at trailing edge <NUM>, and a second end <NUM>, which is opposite first end <NUM> and which is coupled to leading edge ridge <NUM>LE. Core mounting flange <NUM> of core <NUM> may be coupled to inner skin mounting flange <NUM>.

With reference to <FIG>, in various embodiments, core <NUM> may form the lower surface <NUM> of spoiler <NUM>. In other words, in various embodiments, spoiler <NUM> may not include inner skin <NUM>. Lower surface <NUM> of spoiler <NUM> is a non-aerodynamic surface, which allows inner skin <NUM> to be eliminated. Stated differently, in various embodiments, grooves <NUM> may be located immediately adjacent an aerostructure <NUM>. In various embodiments, aerostructure <NUM> comprises a portion of wing <NUM>, with momentary reference to <FIG>.

With reference to <FIG> and <FIG>, a panel <NUM> for forming core <NUM> is illustrated. <FIG> illustrates panel <NUM> prior to forming/shaping core <NUM>. <FIG> illustrates panel <NUM> after forming/shaping core <NUM>. In accordance with various embodiments, panel <NUM> may be folded, bent, or otherwise shaped along dotted lines <NUM> to form ridges <NUM> and along dotted lines <NUM> to form grooves <NUM>. In various embodiments, panel <NUM> includes mounting flange portion <NUM>. Panel <NUM> may be folded, bent, or otherwise shaped, along leading edge <NUM> such that mounting flange portion <NUM> forms core mounting flange <NUM>.

In various embodiments, panel <NUM> may include closeout flanges <NUM>. Closeout flanges <NUM> are located at the inboard end <NUM> and the outboard end <NUM> of core <NUM>. Closeout flanges <NUM> are configured to be formed (e.g., folded) along dotted lines <NUM> at inboard end <NUM> and along dotted lines <NUM> at outboard end <NUM>. Once formed/folded, closeout flanges <NUM> cover the space between adjacent walls <NUM>. For example, closeout flanges <NUM> are interleaved such that a group of first closeout flanges 210a are folded, and/or formed extending, in a first direction relative to dotted line <NUM> and a group of second closeout flanges 210b are folded, and/or formed extending, in a second direction relative to dotted line <NUM>, with the second direction being opposite the first direction. The closeout flanges <NUM> at outboard end <NUM> are folded/formed in a similar manner along dotted line <NUM>. Each of the first closeout flanges 210a covers an area defined by two adjacent grooves <NUM> and the ridge <NUM> located between the two adjacent grooves <NUM>. Each of the second closeout flanges 210b covers an area defined by two adjacent ridges <NUM> and the groove <NUM> located therebetween. In this regard, the closeout flanges <NUM> may form outboard and inboard surfaces extending between outer skin <NUM> and inner skin <NUM>, with momentary reference to <FIG>, and between leading edge <NUM> and trailing edge <NUM>.

With reference to <FIG>, a method <NUM> of forming a control surface is illustrated. Method <NUM> may include forming an outer skin (step <NUM>), forming a thermoplastic panel into a corrugated core having a plurality of ridges and a plurality of grooves (step <NUM>), and coupling the corrugated core to the outer skin (step <NUM>). In various embodiments, step <NUM> includes forming the thermoplastic panel such that plurality of ridges decrease in height between a leading edge ridge of the plurality of ridges and a trailing edge ridge of plurality of ridges.

In various embodiments, step <NUM> comprises heating at least one of the outer skin or the corrugated core such that a matrix material of the fiber reinforced thermoplastic composite material of the corrugated core crosslinks with a matrix material of the fiber reinforced thermoplastic composite material of the outer skin. In various embodiments, method <NUM> may further comprise coupling the outer skin and the corrugated core to an aerostructure (step <NUM>).

In various embodiments, method <NUM> may further include forming an inner skin comprising fiber reinforced thermoplastic composite material, locating the corrugated core between the inner skin and the outer skin, and coupling the corrugated core to the inner skin by heating at least one of the inner skin or the corrugated core such that the matrix material of the fiber reinforced thermoplastic composite material of the corrugated core crosslinks with a matrix material of the fiber reinforced thermoplastic composite material of the inner skin.

In various embodiments, step <NUM> may include heating the thermoplastic panel to a temperature sufficient to cause the thermoplastic material to become pliable. In various embodiments, step <NUM> may include forming a mounting flange at a leading edge of the corrugated core. In various embodiments, step <NUM> may include forming a plurality of closeout flanges extending between adjacent walls at an outboard end and an inboard end of the corrugated core. In various embodiments, step <NUM> may include forming the plurality of ridges having a decreased pitch proximate a trailing edge.

Forming a control surface, such as spoiler <NUM> employing method <NUM> and with a corrugated core <NUM> tends to decrease manufacturing time and costs relative to control surfaces having machined metal cores. Further, using a fiber reinforced thermoplastic composite material for the core and the skins tends to reduce a weight of the control surface and/or allows for a greater density of core material to employed between the skins without increasing the weight of the control surface as compared to metal cores. Finally, employing core (e.g., closeout flanges <NUM>) to cover the inboard and outboard ends, eliminating the need to attach separate closeout structures, which can further reduce the manufacturing time and weight of the control surface.

Systems, methods, and apparatus are provided herein.

Claim 1:
A control surface for an aircraft, comprising:
an outer skin (<NUM>); and
a core (<NUM>) coupled to the outer skin (<NUM>), the core (<NUM>) including a plurality of folded corrugations (<NUM>), wherein a height (H) of the core (<NUM>) decreases in a direction extending from a leading edge (<NUM>) of the control surface to a trailing edge (<NUM>) of the control surface; wherein
the plurality of folded corrugations (<NUM>) comprises a plurality of ridges (<NUM>) and a plurality of grooves (<NUM>), the plurality of ridges (<NUM>) being located at the outer skin (<NUM>) and the plurality of grooves (<NUM>) being located at an inner skin (<NUM>), characterised in that a pitch of the ridges (<NUM>) proximate the trailing edge (<NUM>) is less than a pitch of the ridges (<NUM>) proximate the leading edge (<NUM>).