Aircraft landing gear with, at least, one noise killer

FIELD: transport.

SUBSTANCE: invention relates to aircraft engineering, particularly, to aircraft landing gear with noise killer and to aircraft equipped with said noise killer. Aircraft landing gear comprises noise killer 2, 3 linked with component 4 of said landing gear 1. Said noise killer 2, 3 incorporates separate circuit 5, 6 comprising geometrical cells 7. Note here that said circuit is arranged nearby component 4 so that one of its parts 8, 9 is, in fact, orthogonal with airflow E in final position of said component 4 with landing gear 1 in extended position.

EFFECT: reduced noise generated by air acting of landing gear.

10 cl, 8 dwg

The invention relates to a chassis of an aircraft equipped with at least one means of reducing noise.

More specifically referred chassis that can be reduced in the usual way in one of two positions, namely an upper position and a lower position, is of the type containing at least one means of reducing noise, which is associated at least with one component (pipe, rack, mount, pipe, etc.) mentioned chassis.

The present invention relates to all types of chassis and, in particular, applies equally to the front landing gear and main landing gear, regardless of whether it is under the wing and/or under the fuselage.

It is known that the aerodynamic noise is a critical parameter in Aeronautics and each new aircraft should, in particular, to obtain certification to meet international standards set by ICAO (which is the English acronym for "International civil aviation organization"), which is a very hard noise. In addition, the international civil aviation organization will likely in subsequent years to provide a lower permissible limits of noise. In addition, some airports have installed noise-related restrictions that are more stringent than those the international rules.

It is known that the chassis of the aircraft is a significant source of noise during takeoff and also, especially during landing (phase approach, intermediate and final stages). It is generally accepted that the chassis of the aircraft produces approximately 30% of the total noise generated by the aircraft during landing procedures. In addition, measurements showed that the noise caused by the chassis, is emitted in a wide range of frequencies ranging from a low frequency of about 90 Hz to frequencies greater than 4 kHz. Therefore, the noise emitted by the chassis is not a low-frequency phenomenon and is quite annoying, especially for people living near airports.

This noise is generated essentially by the air flow through the constituent elements of the chassis when the chassis is at the bottom, and this air flow causes the phenomenon of turbulence interacting with structures, causes noise. This is partly due to the fact that not all of the various components (pipes, racks, mounts, wheels, etc.) chassis are aerodynamic. In the context of the present invention believe that the element that is aerodynamic, an element having a shape that causes little disturbance to the air flow, and therefore produces small who is ear turbulence, which is the source of the noise. Therefore, the flow of air that flows around these neurodynamics constituent elements, causing turbulence and noise. Noise generally is created when these elements emit turbulence. In addition, broadband noise may also be generated when the free turbulence interacts with the surfaces of other elements downstream. Therefore the total noise generated chassis, arises primarily from turbulence and its interaction with the elements of the mechanism, whether they are aerodynamic or other.

One way to reduce this noise can be to surround some of the components of the chassis, or even the entire chassis, rigid radomes, which has an aerodynamic shape and provide the ability to keep air flow away from neurodynamics elements. However, a solution such as this leads to numerous disadvantages, such as, in particular, the increase in the cost of manufacture, difficulty in exploring the chassis or some of its constituent elements and weight gain.

Document WO-2004/039671 discloses a means of noise reduction, which is performed on the chassis. This means noise reduction contains, in particular, deflecting fairing, the purpose of which is to change the direction of air is about flow, to keep him away from the noisy components of the chassis that is associated with the fairing. Keeping air away from producing noise zone provides an opportunity to reduce the overall noise. This fairing can be equipped with a perforated area, the goal of which is to limit the number of rejected air and its potential negative impacts. In addition, (neuklonnym) the air that passes through the perforated zone is slowed down so that the resulting noise is also reduced. This earlier document provides that less than half of the surface of this perforated area was actually perforated.

The present invention is to overcome the aforementioned disadvantages. The present invention relates to a chassis of the aircraft, containing at least one means of reducing noise, which is especially preferred (reliable, inexpensive, not very large, light in weight, easy to assemble and so on).

To this end according to the invention mentioned chassis of the aircraft, which can result in one of two positions, namely an upper position and a lower position, and which contains at least one means of reducing noise, which is associated with at least one element mentioned is th chassis, it is noteworthy that the aforementioned means of reducing noise contains at least one private network, which contains the geometry of the cell and which is available at the mentioned integral element in such a way that at least one of its parts is essentially orthogonal to the airflow in the final position (downstream or upstream) of the mentioned compound element, when the chassis is in the lower position, to reduce the noise created by the impact of the air flow in the mentioned composite element).

Preferably, the above network is placed at the mentioned integral element in such a way that at least one of its parts is essentially orthogonal to the airflow downstream of said composite element, when the chassis is in the lower position, in order at least to reduce noise turbulence created downstream of said composite element disruption of the air flow caused by this element.

Thus, on the basis of the invention the said means of noise reduction, which contains a separate network, as defined below, has numerous advantages and in particular:

- provides the ability to effectively reduce noise, as defined below;

- has a light weight;

- is not very large;

- is simple to assemble; and

- does not impact adversely on the operation of various components of the chassis.

In the first embodiment, the above-mentioned network has the form of a sheet, which, in particular, can be flat, curved or V-shaped, and it is placed in final position (preferably downstream) relative to the single integral element.

This first version of the implementation is particularly well suited for reducing noise generated in a single composite elements.

Preferably, the above network, which may be rigid or elastic, has a width, which is in the range between 1.5 and 3 times the lateral dimension of the composite element, and a length essentially equal to the length of this composite element.

In this first embodiment, when the network is located downstream from a composite element that creates turbulence noise emitted by the element loses most of its energy as it passes through the cells of said network, which is located downstream. Thus, this turbulence is virtually eliminated and therefore almost does not cause noise. This network also provides the ability to reject stream upstream from the elements.

Additionally, in this first embodiment, the implementation of the population, when the network is located upstream from the composite element, the flow comes to a composite element, slowed down, and therefore produced less noise. In addition, the shape of the observed flow, is more aerodynamic, and therefore, noise produced below.

In addition, in the second embodiment, the above-mentioned network surrounds (preferably completely) at least one composite element. However, in this case, preferably, the above network surrounds the entire group of elements (tubes, racks, mounts, wheels etc).

Therefore, this second variant implementation is particularly well suited for reducing noise caused by a group of constituent elements of the chassis. In this case, the above-mentioned network, which may, in particular, have prismatic, cylindrical or elliptical shape, preferably made of a metal material (steel, aluminum), thus providing the capability of a network to withstand the flow and to maintain its initial shape. It can also be run from an elastic material (polyester fiber).

In this second embodiment, the network that surrounds a group of elements, is able to reduce the turbulence created by the elements located upstream or some of the elements, surrounded by this network. In addition, the network has Bo is its aerodynamic shape, what group of elements per se so that the air stream reaching the network, and generates less noise. Additionally, in the internal volume formed by the network, the speed of the air reaching the composite element is greatly reduced due to viscous friction, when the air passes through the geometric cells, it also helps to reduce noise.

In addition, in one particular embodiment:

- mentioned geometry (polygonal or round) cell networks have dimensions (such as diameter, if round cells, the length of a side in the case of square cells, and so on)in the range between 0.2 and 12.5 mm and preferably between 1.5 and 2 mm; and/or

- mentioned chassis contains many tools for noise reduction according to the invention, as described above.

The accompanying drawings facilitate an understanding of how the invention can be realized. In these drawings, identical reference position indicate similar elements.

1 to 4 schematically show various alternative forms relating to the first embodiment of implementation of means of reducing noise according to the invention.

5 to 7 depict one exemplary variant of the implementation of means of reducing noise, the appropriate alternative form 1.

Fig partially shows the chassis of the aircraft, equipped with a tool to reduce the Oia noise according to the second variant embodiment of the invention.

The present invention relates to a chassis 1 of the aircraft, for example the front landing gear or the main landing gear, as shown by example in Fig.

This chassis 1, which can result in the usual way in one of two positions, namely an upper position (not shown) in flight and a lower position (Fig) for landing, takeoff or takeoff on earth, contains at least one tool 2, 3 noise reduction, which is associated with at least one composite element 4 (tube, rack, mount, pipe, etc.) chassis 1. Mentioned means 2, 3 noise reduction is depicted according to the first variant implementation of the reference position 2 in figure 1-7 and according to the second variant implementation of the reference position 3 Fig.

According to the invention the said means 2, 3 noise reduction contains at least one private network 5, 6, which contains the geometric cell 7 and which is provided at least one compound of element 4 (non-aerodynamic) chassis 1. This separate network 5, 6 are placed so that at least one of the parts 8, 9 is essentially orthogonal to the air flow, illustrated by arrows E in figure 1, in end position (upstream or downstream) of the mentioned compound element 4, when the chassis 1 is in the lower position the Institute. A separate network 5, 6, such as this provides an opportunity to reduce the noise caused by the effects of the air flow in the mentioned integral element 4, as defined below.

Preferably, the above network 5 place the said composite element 4 in such a way that at least one of its parts 8 is essentially orthogonal to the airflow E, downstream of said composite element 4, when the chassis is in the lower position, as shown in figure 1. It provides the ability to reduce noise turbulence (illustrated curved arrow 10), created downstream of said composite element 4, the disruption of the air flow caused by this composite element 4. This reduction of turbulence is illustrated by the curved arrow 11, drawn by dashed lines, as a replacement curved arrows 10, drawn as a solid line (which illustrate the turbulence). Also located downstream element is able to reject the part of the air flow from the composite item 4.

Thus, on the basis of the invention the said means 2, 3 noise reduction, which contains a separate network 5, 6, has numerous advantages and in particular:

- provides the ability to effectively reduce noise, as defined is but below;

is, by its nature, light in weight;

- is not very large;

- is simple to assemble;

- does not impact adversely on the operation of various components of the chassis 1; and

"it can be applied to any kind of chassis 1.

In the first embodiment, depicted in figure 1-7, the said means 2 noise reduction contains the network 5, which has the form of a sheet and is preferably placed downstream from a single neurodynamical integral element 4, which is depicted as an example in the form of a cylinder 1, 3, 4, and 7. This first version of the implementation is particularly well suited for reducing noise caused by a single individual compound item 4.

According to an alternative variant forms of implementation, the network 5 may, in particular, to have:

- flat shape, as shown in figures 1, 2, 5-7;

- V-shaped, as shown in figure 3; and

- curved shape, as shown in figure 4.

The network 5 is preferably performed either rigid (e.g. metal) material, or a resilient material. Geometric cell 7 can be created in a single part from an elastic material or of thin filaments, or wires (preferably metal). In addition, the mentioned geometric 7 cells have dimensions (e.g., diameter in the case of round cells, the length of the sides in the learn of square cells, and so on), in the range between 0.2 and 12.5 mm and preferably between 1.5 and 2 mm Diameter wires or cores preferably are in the range between 0.1 and 1.2 mm

Referred to a separate network 5 has a width L1, transverse to the air flow E (and to the longitudinal axis of the composite element 4), which preferably is in the range between 1.5 and 3 times the lateral dimension of the composite element 4, namely the diameter d in example 1, 3 and 4. In addition, the length L2 of the mentioned network 5 is preferably essentially equal to the length of the composite element 4, as shown, for example, 7.

In a specific embodiment, (5-7) tool 2 noise reduction contains, in addition to the network 5, the strip 12, which is attached, for example, by metallization, to the network 5, and which is attached to the fasteners 13, for example, clamps. These clamps 13 are of a diameter suitable to the diameter of the cylinder, which forms an integral element 4, and is attached to this cylinder in the usual way, as shown in Fig.7. in order to maintain the network 5 in the appropriate position relative to the aforementioned compound of item 4.

In this first embodiment, when the network 5 is located downstream from the composite element 4, which creates a turbulence noise emitted by the element 4, loses most of its energy when it passes through the cell 7 upomyanutye 5, located downstream, as illustrated in figure 1. Thus, this turbulence is virtually eliminated and therefore almost not generate noise.

In addition, in the second embodiment, depicted in Fig, network 6 surrounds the entire group 14 elements 4 (pipes, racks, fixtures, pipelines etc).

The network 6 may, in particular, have a prismatic, cylindrical or elliptical shape and preferably made of metal material (steel, aluminum), thus providing the capability of a network to withstand the flow and to maintain its initial shape. It can equally be run from an elastic material (polyester fiber). Preferably the geometric cell 7 mentioned network 6 have dimensions (e.g., diameter in the case of round cells, the length of the sides in the case of square cells, and so on)in the range between 0.2 and 12.5 mm and preferably between 1.5 and 2 mm Diameters of the threads or wires are preferably in the range between 0.1 and 1.2 mm

In this second embodiment, the network 6, which surrounds the group 14 elements 4, is able to reduce the turbulence created by the elements located upstream (in the direction of air flow E) or some of the elements 4, surrounded by the network 6. In addition, the above-mentioned network 6 has more aerodynam the ical form, than the group 14 elements 4 per se so that the air stream reaching the mentioned network 6, and generates less noise than the air flow, which would have reached group 14, when the network 6).

In addition, in the internal volume 15, formed by the network 6, the air velocity is greatly reduced due to viscous friction, when the air passes through the geometric cell 7. Therefore, the noise (which is proportional to the speed to the power 6) becomes smaller.

Chassis 1 according to the invention in one specific embodiment, can contain many such tools 2, 3 noise reduction.

1. The chassis of the aircraft, which can result in one of two positions, namely an upper position and a lower position, and which contains at least one means (2, 3) noise reduction, which is associated with at least one constituent element (4) of the said chassis (1), in which the said means (2, 3) noise reduction contains at least one private network (5, 6), which contains geometrical cells (7) and which is available at the mentioned composite element (4) so that at least one of its parts (8, 9) is essentially orthogonal to the airflow (F) in end position mentioned constituent element (4)when the chassis (1) is in its lower position, to reduce the noise generated by impacts of air flow (E) of the mentioned compound element (4).

2. Chassis according to claim 1 in which the said chain (5, 6) located at the aforementioned composite element (4) so that at least one of its parts is essentially orthogonal to the airflow (F) downstream of said composite element (4)when the chassis (1) is in its lower position, so that at least to reduce noise turbulence created downstream of said composite element (4), disruption of the air flow caused by this composite element (4).

3. Chassis according to claim 1 in which the said network (5) has the form of a sheet, and in which it was placed in the final position in relation to a single composite element (4).

4. Chassis according to claim 3 in which the said network (5) has a width (L1), which is in the range between 1.5 and 3 times the transverse dimension (d) of the composite element (4).

5. Chassis according to claim 1 in which the said network (6) surrounds at least one composite element (4).

6. Chassis according to claim 5 in which the said network (6) surrounds the group (14) of the constituent elements (4).

7. Chassis according to claim 5 in which the said network (6) is made of a metal material.

8. Chassis according to claim 1, in which the mentioned geometrical cells (7) network (5, 6) have dimensions in the range between 0.2 and 12.5 mm

9. Chassis according to claim 1, which contains a variety of tools (2, 3) is menichini noise.

10. Aircraft, while it contains the chassis (1)as defined in claim 1.