Patent Description:
In commercial aircraft, the icing of wing components and control surfaces is often prevented by using de-icing or anti-icing devices. A common approach to achieve this is to heat up respective parts with bleed air from turbofan engines. Usually, not all leading-edge components are equipped with de-icing or anti-icing devices. Instead, the components further outboard are heated up, while further inboard components remain unprotected. However, for routing bleed air having an elevated temperature into regions outboard of an engine installation position, a supply duct is installed partially in a fixed wing structure and extends from an engine to the first leading-edge component to be heated in an outboard direction. Thus, a part of the fixed wing needs to be equipped with thermal shielding devices to avoid an excessive heat transfer into sensitive components, such as mechanical structures, electrical cables and other conduits. This leads to completely bypassing a slat arranged between the engine installation position and the first slat to be heated.

<CIT> describes a leading edge/anti-icing assembly for an airfoil comprising a leading edge slat having a nose section defining a heat exchange chamber. Anti-icing air directed into the heat exchange chamber flows rearwardly through the slat so as to have a deicing function, and is then discharged in a rearward direction from the trailing edge of the slat. Thus, the anti-icing air not only performs an anti-icing function over the upper surface of the slat, but also contributes to anti-icing over the upper surface portion of the main wing rearwardly of the trailing edge of the slat.

<CIT> describes an aircraft slat assembly comprising a pair of slats separated by a gap. A weather seal seals the gap between the slats and forms part of an outer aerodynamic surface of the slat assembly. An anti-icing system is provided with a pair of piccolo tubes, each tube being housed within a respective one of the slats and having spray holes for delivering hot gas to a leading edge of the slat in which it is housed. A flexible duct delivers hot gas between the piccolo tubes, the flexible duct passing across the gap between the slats. A vent in the weather seal can open to permit hot gas from the anti-icing system to exit the gap between the slats.

It is an object of the invention to provide an alternate leading-edge arrangement, which has improved impact characteristics regarding manufacturing costs and shielding requirements for surrounding structures.

The object is met by a leading-edge arrangement for an aircraft having the features of independent claim <NUM>. Advantageous embodiments and further improvements can be gathered from the subclaims and the following description.

A leading-edge arrangement for an aircraft is proposed, comprising a plurality of movable flow bodies, a thermally insulated supply duct, an air transfer duct, and at least one perforated tube, wherein the movable flow bodies are arranged in a consecutive arrangement to form a row with a first end and a second end, wherein the supply duct reaches into an interior of one of the flow bodies at the first end, wherein the air transfer duct connects to the supply duct, comprises a thermal insulation, and extends at least through the interior of the respective flow body directly from the first end in the direction towards the second end through at least two consecutive flow bodies, wherein the at least one perforated tube is arranged inside at least one of the flow bodies that directly follows on, wherein the at least one perforated tube is in fluid communication with the transfer duct, and wherein the transfer duct is configured to transfer air from the supply duct into the at least one perforated tube.

The movable flow bodies may particularly comprise leading edge devices, which are a part of a high lift system of an aircraft. They may exemplarily be realized as a leading-edge flap or a leading-edge slat. The invention focuses on aspects of an anti- or de-icing system and movable flow bodies that are to be equipped with an anti- or de-icing system may be considered. While some of the advantages or features are explained using a leading-edge device as an example, this does not rule out other kinds of flow bodies.

The flow bodies are configured to be movable components and may thus comprise flanges, brackets, holders, lugs, or similar features that allow to couple the flow bodies with appropriate drive devices. In some cases, the flow bodies may include ribs and/or spars, which may comprise a protruding section that allows to swivably couple a component to the respective flow body.

The plurality of movable flow bodies may comprise two, three, four, five or more flow bodies. They are configured to be positioned in a consecutive arrangement. They may each comprise at least one delimiting edge or face, wherein the delimiting edges or faces of the plurality of the flow bodies complement each other to form a leading edge or a part of a leading edge of a wing or to follow a general direction of a leading edge of a wing.

The flow bodies may be configured to be arrangeable in a flush manner next to each other. However, they may also enclose gaps between each other. This may depend on the desired application of the leading-edge arrangement according to the invention. The supply duct acts as an interface to feed in air from an external device. As the at least one perforated tube is provided for ejecting air into an interior of at least a part of the flow bodies, it is beneficial to provide air having an elevated temperature. This may, for example, be provided by an engine of the aircraft, to which the arrangement according to the invention is to be mounted. For example, the respective engine or engines may each comprise at least one bleed air port, which is to be coupled with the supply duct. Between the bleed air port(s) and the supply duct at least a valve and a restrictor may be provided, wherein the restrictor may be a part of the supply duct or it may be an external component.

It is desired that the supply duct ends as close to the first end of the arrangement as possible. Thus, its length may be greatly reduced in comparison with common supply ducts. By integrating the air transfer duct into the flow body at the first end, air that is supplied through the supply duct can be transferred through the transfer duct to the at least one perforated tube, which may be placed in an adjacent flow body that is not directly placed at the first end.

Since the air transfer duct extends at least through the interior of the respective flow body, into which the supply duct reaches, air is only forwarded through the respective flow body. Hence, the respective flow body directly at the first end merely acts as a feature for holding the transfer duct.

The air transfer duct comprises a thermal insulation to avoid loss of thermal energy during the transfer of the air to the at least one perforated tube. Since substantially no other installations to be protected from heat are provided in the flow body at the first end, the insulation may be realized in a more simple fashion than with the supply duct.

For example, the first flow body may be a leading edge device that is not equipped with an anti-icing or de-icing feature. However, by including an air transfer duct into the flow body at the first side, the supply duct may be realized with an as short length as possible. By including the air transfer duct into the flow body, a hollow space that usually remains substantially unused for other purposes now acts for transferring the air at an elevated temperature to the flow bodies that require anti- or de-icing. Other spaces, to which the leading-edge arrangement may be attached, do not need to carry the supply duct and thus, the requirements for an integration of the supply duct are reduced. For example, in common installations different conduits, electrical lines or other elements may be arranged in a fixed wing component, to which the leading-edge arrangement is to be attached. By reducing the length of the supply duct and transferring the air inside the flow body at the first end, less heat and mechanical shielding measures need to be provided in the fixed wing component. Since the flow body usually does not comprise these sensitive conduits and lines, a greatly reduced thermal and mechanical shielding is required. In turn, this leads to reduced manufacturing costs and effort as well as to a reduced weight, while at least maintaining the same level of safety and reliability.

In a preferred embodiment, the at least one perforated tube is a piccolo tube configured to eject air to form a thermal anti- or de-icing device. The piccolo tube may comprise perforations that are arranged on at least a part of a peripheral surface. The perforations may be arranged in lines or staggered. However, they geometrical extent of the perforations may be limited to a certain angular range of the peripheral surface. This angular range may be adapted to the shape of the flow bodies, such that air is ejected to impinge on interior surfaces of the flow bodies that need to be heated for the desired anti- or de-icing effect. The angular range may exemplarily include angles of <NUM> to <NUM> degrees. The angular range may be greater or smaller, if desired. Preferably, the piccolo tube is made from a metallic material.

In another advantageous embodiment, the supply duct is configured to route bleed air from an aircraft engine to the air transfer duct and the at least one piccolo tube. The supply duct may thus comprise a sufficient thermal insulation to avoid an excessive temperature at its peripheral surface. Brackets and holders for attaching the supply duct may be provided with a sufficient thermal de-coupling as well. The supply duct may include a plurality of bends to be configured to route bleed air e.g. from a nacelle of an engine into the region of the first end.

Furthermore, the flow bodies may each comprise a forward end and a rear end, wherein the supply duct extends through the rear end of the flow body at the first end. The forward end may comprise a leading edge of the flow body, at least in an extended state of the flow body, wherein the leading edge may in particular be arranged on a curved surface. The shape of the rear end heavily depends on the kind of flow body. While the rear end may comprise a low height and is merely realized in the form of an elongated edge, it may also comprise a flat or curved surface that may be indented in the direction of the forward end. The supply duct extends into the rear end preferably in cases where the flow body will be moved with a distinct translational motion to increase the distance between the rear end of the flow body and the part to which it is movably attached. By providing the supply duct to extend through the rear end it may easily follow the movement of the flow body by using a telescopic duct section that is extended or retracted during the movement of the flow body.

Consequently, it is preferred if the supply duct comprises a telescopic duct section extending through the rear end of the flow body that is arranged at the first end, wherein the telescopic duct section is in fluid communication with an angular connector, which connects to the air transfer duct. The angular connector may bend from a chordwise into a spanwise direction of the respective flow body.

According to the invention, the air transfer duct extends into at least two flow bodies. To avoid a canting of the air transfer duct, it may comprise an elastic coupling to be arranged between the adjacent flow bodies. The elastic coupling may exemplarily comprise a bellows arrangement.

In a preferred embodiment the air transfer duct is coupled with the at least one piccolo tube in the interior of one of the flow bodies. Consequently, the air transfer duct may reach into a flow body, which is to be equipped with an anti-icing or deicing function. The air transfer duct may exemplarily just reach into the interior of the respective flow body or it may extend further into the interior. Thus, it may be possible to reduce the length of the piccolo tube in the respective flow body to reduce the anti- or de-icing effect.

In another advantageous embodiment, the air transfer duct is coupled with the at least one piccolo tube between two adjacent flow bodies. The coupling may include an elastic coupling that is configured to compensate a relative motion between the adjacent flow bodies. By providing the coupling between adjacent flow bodies, a maximum length of the piccolo tube inside the flow body is possible.

Still further, a section of <NUM> to <NUM> percent and preferably of <NUM> to <NUM> percent of a length of the air transfer duct comprises perforations to eject air that is transferred by the air transfer duct. Thus, also the air transfer duct may provide an anti-icing or deicing function at least in a section of the respective flow body.

Preferably, the perforations of the air transfer duct are arranged at a side of the respective flow body that faces away from the first end. Thus, a section near the consecutive flow body can be subjected to an anti-icing or de-icing function.

In an advantageous embodiment a transition section in the interior of one of the flow bodies connects one of the at least one perforated tube and the air transfer duct. The transition section can be a rigidly or elastically coupled element. The transition section may comprise the same or a different diameter as the at least one perforated tube. In a simple embodiment, it may be made from a plastic material or a metallic material that withstands the expected temperature.

Still further, the flow bodies may be leading-edge high lift devices. As explained above, they may particularly be realized as leading-edge slats, leading-edge flaps or droop nose devices.

The invention further relates to a wing having a fixed wing component and a leading-edge arrangement according to the above description, wherein the flow bodies of the leading-edge arrangement are movably supported on the fixed wing component, and wherein the supply duct extends through a section of the fixed wing component.

In an exemplary embodiment of the wing, the flow bodies comprise at least one of a leading-edge slat and of a droop nose device.

Still further, the invention relates to an aircraft having two wings according to the above, as well as engines attached to the wings, wherein the supply duct of each wing extends from an engine to the leading-edge arrangement. The engines may be turbofan or turboprop engines that are attached to an underside or a top side of the wings. It is clear that the supply duct explained further above extends from at least one compressor stage to the first side of the arrangement according to the invention. For avoiding excessive air temperatures, upstream of the supply duct a heat exchanger may be provided that is configured to dissipate heat from the bleed air to the environment.

Other characteristics, advantages and potential applications of the present invention result from the following description of the exemplary embodiments illustrated in the figures. Furthermore, identical or similar objects are identified by the same reference symbols in the figures.

<FIG> shows a leading-edge arrangement <NUM>, not falling within the scope of the claims. The arrangement is attached to a fixed wing component <NUM> of a wing <NUM> of an aircraft. It is noted that the shown setup of the arrangement <NUM> is not to scale and merely acts as an exemplary illustration. Also, the arrangement <NUM> shows a certain type of components, which may also be replaced by components of a completely other type.

The arrangement <NUM> comprises a first end <NUM> and a second end <NUM>, wherein flow bodies <NUM>, <NUM> and <NUM> form a consecutive arrangement in the form of a row. Still further, there is a further inboard flow body <NUM>, which is not of particular relevance in the following description. The flow body <NUM>, which is directly arranged at the first and <NUM> is referred to as a first flow body <NUM>, while the consecutive flow body <NUM> is named second flow body <NUM> and the further consecutive flow body <NUM> is named third flow body <NUM>. The second and third flow bodies <NUM> and <NUM> provide a de-iced group <NUM>, which are actively provided with hot air for anti- or de-icing, while the first flow body <NUM> remains without any icing protection. In the example, all flow bodies <NUM>, <NUM>, <NUM> (and <NUM>) are realized as leading-edge slats. They are coupled with drive devices (not shown), such that they can be brought into extended positions and into a retracted position shown in <FIG>.

An engine <NUM> is arranged underneath the fixed wing component <NUM>. It may be realized in the form of a turbofan engine, which comprises at least one bleed air port <NUM>. Here, air is tapped from at least one compressor stage and delivered into a supply duct <NUM>. The supply duct <NUM> extends from the engine <NUM> into the direction of the first end <NUM>.

The first flow body <NUM>, the second flow body <NUM> and the third flow body <NUM> each comprise a rear end <NUM> and a forward end <NUM>. The forward end <NUM> of the flow bodies <NUM>, <NUM> and <NUM> follow a direction of a leading edge <NUM> of the wing <NUM>, to which the arrangement <NUM> as well as the fixed wing component <NUM> are associated. The supply duct <NUM> is routed into the first flow body <NUM> through the rear end <NUM> as close to the first end <NUM> as possible. Consequently, the length of the supply duct <NUM> is as short as possible. Inside the first flow body <NUM>, and air transfer duct <NUM> is arranged. It is in fluid communication with the supply duct <NUM> and exemplarily comprises an angular connector <NUM>, such that the direction of flow coming from the supply duct <NUM> and running into the air transfer duct <NUM> is bent about roughly <NUM>°.

Air supplied by the supply duct <NUM> is thus transferred completely through the first flow body <NUM>, without any interaction with the first flow body <NUM>. Then, at a transition <NUM> between the first flow body <NUM> and the second flow body <NUM>, a piccolo tube <NUM> is attached to the air transfer duct <NUM>. The piccolo tube <NUM>, which is a perforated tube, allows air to be ejected through perforations <NUM> into an interior <NUM> of the respective flow bodies <NUM> and <NUM>. Thus, a skin <NUM> of the flow bodies <NUM> and <NUM> is heated up, which effects an anti- or deicing function.

By reducing the length of the supply duct <NUM> as much as possible, the installation and required shielding effort for the air supply duct <NUM> is minimized. Less geometrical regions of the fixed wing component <NUM> and therefore less electrical lines and conduits inside the fixed wing component <NUM> need to be protected from heat emanating from the supply duct <NUM>. The first flow body <NUM> hardly encloses other installation features, such that the air transfer duct <NUM> may not require an as sophisticated thermal shielding as the supply duct <NUM>. Hence, routing the supply duct <NUM> around the first flow body <NUM> to reach into the second flow body <NUM>, as commonly found in commercial aircraft, is not required. Also, a forward spar <NUM> of the fixed wing component <NUM> is less exposed to heat during an anti- or de-icing time interval.

As demonstrated in <FIG>, the air transfer duct <NUM> extends further into the second flow body <NUM> in order to reduce the length of the anti- or deiced group <NUM>. The air transfer duct <NUM> may exemplarily reach to a transition section <NUM> inside the second flow body <NUM>. However, it may also be possible to let the air transfer duct <NUM> reach completely through the first and second flow bodies <NUM> and <NUM> and perforate a part of the air transfer duct <NUM> that corresponds to the distance between the transition region <NUM> and the outboard delimitation of the second flow body <NUM> as shown in <FIG>. Thus, there is an unperforated inboard region <NUM> inside the second flow body <NUM>.

<FIG> demonstrates the first, second and third flow bodies <NUM>, <NUM> and <NUM> in extended positions. Here, for transferring the air from the supply duct <NUM> into the air transfer duct <NUM>, a telescopic duct section <NUM> is provided, which follows the motion of the first flow body <NUM>.

Finally, <FIG> shows an aircraft <NUM> having a fuselage <NUM>, wings <NUM> and at least one leading-edge arrangement <NUM> provided on the wings <NUM>. Exemplarily, the aircraft <NUM> comprises two engines <NUM>, which are realized as turbofan engines. These often comprise two or more bleed air ports, which are connectable to the supply duct <NUM>.

Claim 1:
A leading-edge arrangement (<NUM>) for an aircraft, comprising:
- a plurality of movable flow bodies (<NUM>, <NUM>, <NUM>, <NUM>),
- a thermally insulated supply duct (<NUM>),
- an air transfer duct (<NUM>), and
- at least one perforated tube (<NUM>),
wherein the movable flow bodies (<NUM>, <NUM>, <NUM>) are arranged in a consecutive arrangement to form a row with a first end (<NUM>) and a second end (<NUM>),
wherein the supply duct (<NUM>) reaches into an interior (<NUM>) of one of the flow bodies (<NUM>) at the first end (<NUM>),
wherein the air transfer duct (<NUM>) connects to the supply duct (<NUM>), comprises a thermal insulation, and extends at least through the interior (<NUM>) of the respective flow body (<NUM>) directly from the first end (<NUM>) in the direction towards the second end (<NUM>) through at least two consecutive flow bodies (<NUM>, <NUM>),
wherein the at least one perforated tube (<NUM>) is arranged inside at least one of the flow bodies (<NUM>,<NUM>) that directly follows on,
wherein the at least one perforated tube (<NUM>) is in fluid communication with the air transfer duct (<NUM>), and
wherein the air transfer duct (<NUM>) is configured to transfer air from the supply duct (<NUM>) into the at least one perforated tube (<NUM>).