Vented leading-edge assembly and method for manufacturing a vented leading-edge assembly

A vented leading-edge assembly is provided, the assembly including: a slat having a bay and a top skin delimiting a portion of the bay; a spar being arranged in the slat, the spar dividing the bay in a front bay and an aft bay; and a plurality of channel sidewalls being arranged between the top skin and the spar, the plurality of channel sidewalls defining a plurality of channels between the front bay and the aft bay, wherein at least a portion of the spar defines lower channel walls for the plurality of channels.

FIELD OF THE INVENTION

The invention relates to a vented leading-edge assembly, the assembly comprising: a slat comprising a bay and a top skin delimiting a portion of the bay; a spar being arranged in the slat, the spar dividing the bay in a front bay and an aft bay; and a plurality of channel sidewalls being arranged between the top skin and the spar, the plurality of channel sidewalls defining a plurality of channels between the front bay and the aft bay and a method for manufacturing a vented leading-edge assembly.

BACKGROUND OF THE INVENTION

Aircrafts flying at great heights may be subject to icing of the wings. Typically, the ice may form on the leading-edge of the wing. The leading-edge of the wing may comprise a slat. A common approach to prevent icing is to heat up the concerned parts with bleed air from the engines. This is not trivial since the slat body usually comprises a spar which separates the interior structure of the slat into two chambers. Furthermore, the bleed air streams out of the tube which is arranged in a front chamber of the slat. To lead the bleed air between the two chambers in the slat it is known to provide a special part between the upper part of the spar and the top skin of the slat. That special part comprises channels which allow the bleed air to travel from one chamber to another. The aft chamber of the slat may further comprise an air outlet to the outside of the slat to compensate the pressure which is increased by the inflowing bleed air.

According to CN 2014 72669 U the upper skin of the slat comprises grooves on its inner side. The grooves are covered by an inner skin which is arranged between the spar and the inner side of the top skin of the slat.

The manufacturing of the grooves or the special part requires complex milling which may lead to a long and expensive production cycle.

BRIEF SUMMARY OF THE INVENTION

Thus, there may be the need for providing an improved leading-edge assembly and an improved method of manufacturing a leading-edge assembly.

According to an embodiment of the invention, a vented leading-edge assembly is provided, the assembly comprising: a slat comprising a bay and a top skin delimiting a portion of the bay; a spar being arranged in the slat, the spar dividing the bay in a front bay and an aft bay; and a plurality of channel sidewalls being arranged between the top skin and the spar, the plurality of channel sidewalls defining a plurality of channels between the front bay and the aft bay, wherein at least a portion of the spar defines lower channel walls for the plurality of channels.

An aspect of the invention therefore provides channels which are defined by the channel sidewalls and the spar as lower channel wall for each channel. Furthermore, the top skin of the slat may provide an upper channel wall for the channels. The channel sidewalls are separate elements from the top skin of the slat and from the spar. Consequently, milling procedures on the slat or on the spar to provide sidewalls which are integral to the slat or the spar are avoided. Furthermore, since at least a portion of the spar defines a lower channel wall for each of the plurality of the channels, for manufacturing the channels the channel sidewalls may just be placed on the portion of spar between the spar and the top skin of the slat. This simplifies and accelerates the production of the vented leading-edge assembly. This allows a high rate production of the vented leading-edge assembly. Furthermore, since milling is avoided, the production of the vented leading-edge is simple and cost-effective.

In an example, the plurality of channel sidewalls is non-parallel to each other such that a distance between the plurality of channel sidewalls at the front bay is bigger than a distance between the plurality of channel sidewalls at the aft bay.

Due to the different distances between the channel sidewalls and non-parallel channel sidewalls the cross section of the channel reduces from the front bay to the aft bay. A flow of bleed air starting in the front bay will be accelerated when passing the channels in direction of the aft bay. Due to the acceleration of the bleed air flow, the flow keeps its flow direction after exiting the channel which leads the bleed air flow along the total length of the top skin. This avoids a stop or a dissipation of the bleed air flow before reaching the end of the top skin of the slat being distal to the leading-edge of the slat. Consequently, the complete top skin of the slat may be heated by the bleed air.

In another example, the plurality of channel sidewalls is parallel.

In this example, the channels being formed by the channel sidewalls do not accelerate the bleed air flow. Such channels may be provided if the pressure of the bleed air flow is sufficient to flow along the entire length of the top skin.

In a further example, the leading-edge assembly comprises a plurality of fastening elements connecting the top skin to the spar through the plurality of channel sidewalls.

That kind of connection of the plurality of channel sidewalls to the top skin and to the spar is simple and cost effective.

Furthermore, in an example, the plurality of channel sidewalls is provided by a perforated strip being arranged between the top skin and the spar. The perforated strip may comprise a single row of perforations along the length of the strip.

Such a perforated strip can be easily produced by stamping the row of perforations into the strip. Alternatively, the strip may be laser cut, water jet cut, electron beam cut or further cutting methods. The material between the perforations on the strip defines the channel sidewalls. The stamping may further define the shape of the perforations and thus the angle between the channel sidewalls. When mounting the perforated strip on the spar, the row of perforations may be arranged such that they bridge the complete portion of the spar which defines the lower channel wall of the plurality of channels. Furthermore, they may be mounted such that they are in fluid communication with the front bay and the aft bay. Thus, by just mounting the perforated strip between the spar and the top skin of the slat, all of the plurality of channel sidewalls may be provided at once.

In another example, the plurality of channel sidewalls is provided by a comb being arranged between the top skin and the spar.

In this example, the teeth of the comb define the channel sidewalls. The comb may for example be manufactured by stamping, laser cutting, water jet cutting or electron beam cutting. Alternatively, one portion of a perforated strip may be removed, wherein the portion is in contact with the row of perforations. Both alternatives provide a simple way to mount the channel sidewalls between the spar and the top skin of the slat. Furthermore, the comb provides channels which, at least at one end, do not have any material obstructing the airflow.

In an example, the channel sidewalls comprise a common flange protruding from the plurality of channel sidewalls and extending along the spar, wherein preferably fixation elements connect the flange to the spar.

The flange provides an increased stability for the fixation of the channel sidewalls to the spar. This further increases the area moment of inertia of a structure. Thus, the stability of the vented leading-edge assembly is improved.

Moreover, in another example, the front bay comprises a de-icing air outlet being configured to fill the front bay with de-icing air.

In that example, the de-icing air outlet may be a bleeding air outlet being in fluid communication with an engine of an aircraft.

According to an embodiment of the invention, also an aerospace vehicle is provided, the aerospace vehicle comprising: a wing; and a vented leading-edge assembly according to the above description; wherein the vented leading-edge assembly is arranged on a leading-edge of the wing.

The effects and further embodiments of an aerospace vehicle according to the present invention are analogous to the effects and embodiments of the description mentioned above. Thus, it is referred to the above description of the vented leading-edge assembly.

According to an aspect of the invention, also a method for manufacturing a vented leading-edge assembly is provided, the method comprising the following steps: providing a slat comprising a bay and a top skin delimiting a portion of the bay; arranging a spar in the bay such that the spar divides the bay into a front bay and an aft bay; providing a strip comprising a row of a plurality of perforations; and connecting the strip between the spar and the top skin such that each perforation is in fluid communication with the front bay and the aft bay forming a channel between the front bay and the aft bay.

The effects and further embodiments of a method according to the present invention are analogous to the effects and embodiments of the description mentioned above. Thus, it is referred to the above description of the vented leading-edge assembly.

In an example, the method further comprises at least one of the following steps: removing at least one portion of the strip being arranged between the row and the aft bay; removing at least one portion of the strip being arranged between the row and the front bay.

This may remove obstacles in the path of the streaming air and further reduces the weight of the leading-edge assembly.

DETAILED DESCRIPTION

FIG. 1shows a schematic drawing of a vented leading-edge assembly which in its entirety is denoted with reference sign10.

The vented leading-edge assembly10comprises a slat12having a top skin16and a rear skin35. The top skin16and the rear skin35delimit portions of a bay14which forms a chamber inside the slat12. The rear skin35comprises openings36which provide a fluid communication between the bay14and the space outside of the slat12.

The vented leading-edge assembly10further comprises a spar18. The spar18is arranged in the bay14of the slat12. The spar18comprises a portion30which is arranged parallel to the top skin16. Furthermore, the spar18divides the bay14into a front bay20and an aft bay22. The front bay20is arranged closer to the leading-edge of the slat12than the aft bay22.

To de-ice the slat12, the vented leading-edge assembly10may for example comprise a de-icing air outlet32which may be arranged in the front bay20. The de-icing air outlet32may be a pipe which is in fluid communication with an engine of an aerospace vehicle. The engine provides bleeding air to the pipe. The de-icing air outlet32may then comprise outlet openings34which allow the bleed air to be introduced into the front bay20.

The vented leading-edge assembly10further comprises a plurality of channel sidewalls24being provided between the portion30of the spar18and the top skin16. For example, the channel sidewalls24may be sheets, plates or portions thereof. In combination with the portion30and the top skin16, the plurality of channel sidewalls24provide a plurality of channels26being arranged between the top skin16and the spar18. The portion30of the spar18then forms a lower channel wall28for each of the plurality of the channels26. Those plurality of channels26provide fluid communication between the front bay20and the aft bay22.

Fastening elements38may be provided to fix the spar18to the top skin16. Those fastening elements38may be rivets or screws or the like. The fastening elements38connect the top skin16through the plurality of channel sidewalls24to the portion30of the spar18.

An example of an airflow of de-icing air is indicated inFIG. 2. The de-icing air which may be bleed air from an aircraft engine exits from the de-icing air outlet32and flows along the walls of the front bay20. This means, that the skin of the slat12at the front bay20is heated by the de-icing air. The de-icing air flows along the top skin16towards the spar18. At the spar18, the de-icing air flows through the plurality of channels26from the front bay20to the aft bay22. The flow of the de-icing air continues along the top skin16in the aft bay22. The inflowing de-icing air increases the pressure in the aft bay22. This increased pressure leads to a flow towards and through the openings36in the rear skin35. The openings36vent the aft bay22to the outside air.

A more detailed view of the plurality of channels26is shown inFIGS. 3aand 3b.FIG. 3aprovides a view through the plurality of channels26. The top skin16, the plurality of channel sidewalls24and the portion30of the spar18are shown in a cross-sectional view. The fastening elements38are arranged at the positions of the plurality of channel sidewalls24to connect the top skin16to the portion13. The fastening elements38travel through the plurality of channel sidewalls24in a one-to-one manner. However, also more than one fastening element38per channel sidewall24may be provided.

FIG. 3bprovides a top view on the mounted plurality of channel sidewalls24. This view may also be understood as a view from the inner side of the top skin16down to the spar18. The plurality of channel sidewalls24are arranged on the portion30of the spar18. This view shows that the portion30provides the lower channel walls28for the plurality of channels26between the plurality of channel sidewalls24. Furthermore, the openings40in the plurality of channel sidewalls24denote the position of the fastening elements38which connect the top skin16to the spar18by being arranged through the plurality of channel sidewalls24.

InFIG. 3b, the plurality of channel sidewalls24are angled to each other. The distance between the channel sidewalls24at the front bay20is larger than the distance between the channel sidewalls24at the aft bay22. This leads to a diminishing cross-section for the plurality of channels26from the front bay20to the aft bay22. Therefore, an airflow flowing through the plurality of channels26from the front bay20to the aft bay22will be accelerated due to the diminishing cross-section. The acceleration of the airflow ensures that the airflow along the top skin16in the aft bay22reaches the end of the top skin16, i.e. flows along the whole length of the top skin16.

The angle between the channel sidewalls24of the single channel26determines the amount of acceleration of an airflow streaming through the channel26. Thus, the acceleration of the airflow may be adjusted by choosing the angle between the plurality of channel sidewalls24of the plurality of channels26. It is also possible, to provide a plurality of parallel channel sidewalls24, i.e. no acceleration is provided to the airflow through the plurality of channels26.

For arranging the plurality of channel sidewalls24to the portion30of the spar18, the plurality of channel sidewalls24may be provided on a perforated strip42or a comb44.FIGS. 4ato 4cshow examples of perforated strips42and a comb44.

FIG. 4ashows a perforated strip42comprising trapezoidal perforations. The perforations may be provided to the strip42by stamping, i.e. trapezoidal-shaped parts may be stamped out of the strip. Alternatively, the parts may be produced by laser cutting, water jet cutting or electron beam cutting. The perforations define the position of the plurality of channels26. The material of the strip42between the perforations forms the plurality of channel sidewalls24. The plurality of channel sidewalls24may further be provided with openings40for feeding through fastening elements.

FIG. 4bshows a perforated strip42comprising a plurality of channel sidewalls24being parallel to each other.

FIG. 4cshows a comb44. The teeth of the comb44provide the plurality of channel sidewalls24. The shape of the teeth defines the shape of the plurality of channel sidewalls24. The space between the teeth define the location of the plurality of channels26.

According toFIG. 5, the perforated strip42or the comb44may be arranged between the portion30and the top skin18, whereinFIG. 5does not show the top skin18for the sake of an unobstructed view. The perforations bridge the portion30such that the perforations are in fluid communication with the front bay20and the aft bay22.

A portion46of the perforated strip42being arranged in the aft bay22may be removed to remove a possible obstacle of the airflow flowing out of the plurality of channels26into the aft bay22. However, the removal of the portion46may not be required if the perforated strip42is thin in the direction between the portion30of the strap18and the top skin16such that the airflow is not obstructed by the portion46.

Furthermore, a portion48of the perforated strip42being arranged in the front bay20may also be removed. This also applies to the comb44. This may also improve the airflow through the plurality of channels26since the portion48may provide an obstacle for the entry of the air into the plurality of channels26. Thus, the entry of the air into the plurality of channels26may be simplified by the removal. Also, in this case, the removal may not be required if the perforated strip42or the comb44are thin in direction between the portion30of the strap and the top skin16.

FIGS. 6aand 6bshow an alternative exemplary embodiment of the invention. In this embodiment, as shown inFIG. 6a, the portion48of the perforated strip42being arranged between the spar18and the top skin16is bend away from the top skin16towards the spar18. The portion48therefore forms a flange50which is connected to the plurality of channel sidewalls24. Furthermore, the flange50may be connected to the spar18by fastening elements38. The presence of the flange50has the effect that the perforated strip42is angled which improves the area moment of inertia of the perforated strip42. Thus, this embodiment comprises an increased stability.

The perforated strip42according toFIG. 6ais bend after mounting the perforated strip42between the strap18and the top skin16.

FIG. 6bshows a perforated strip42which is a bend before the installation on the strap18.

The skilled person understands that also the portion46of the perforated strip42may be bend towards the strap18to provide a flange (not shown). This will have analogous effects to as the bending of portion48.

FIG. 7shows an aircraft as an example of an aerospace vehicle52comprising a wing54with a leading-edge. The vented leading-edge assembly10may be arranged at the leading-edge of the wing54. Thus, the vented leading-edge assembly10provides the slat12for the wing54.

FIGS. 8aand 8bshow different exemplary embodiments of a method100for manufacturing a vented leading-edge assembly according to the above description.

In step102, a slat comprising a bay and a top skin is provided. The top skin delimits a portion of the bay.

In step104, a spar is arranged in the bay of the slat. The spar divides the bay into a front bay and an aft bay.

According to step106, a strip comprising a row of a plurality of perforations is provided. The strip is therefore a perforated strip. The material between the perforations define a plurality of channel sidewalls. Alternatively, also a comb comprising a plurality of teeth may be provided wherein those teeth define a plurality of channel sidewalls.

According to step108, the strip is connected between the spar and the top skin. The connection is performed such that the perforations bridge the spar, i.e. providing fluid communication between the front bay to the aft bay. This means, that one portion of the perforations opens to the front bay and another portion of the perforations opens to the aft bay. A portion between the front bay and the aft bay provides a channel which is arranged between the spar and the top skin. Furthermore, this means, that a portion of the spar defines a lower channel wall for those channels.

According toFIG. 8a, the method may comprise step110in which at least one portion of the strip being arranged between the row of perforations and the aft bay is removed. Optionally, also step112may be provided in which at least one portion of the strip being arranged between the row of perforations in the front bay may be removed.

The removal of the portions may improve the airflow from the front bay through the plurality of channels to the aft bay along the top skin.

According toFIG. 8b, step110may be left out and only step112may be performed.