CN-122029103-A - Aircraft landing gear assembly

Abstract

An aircraft landing gear assembly (36) comprising a wheel and brake assembly and a shock strut (37) comprising a mounting bearing for movably coupling the aircraft landing gear assembly to an aircraft for movement between a stowed condition for flight and a deployed condition for take-off and landing, the aircraft landing gear assembly further comprising a noise inducing region (37), a first perforated plate fairing (1 n), and a second perforated plate fairing (3 n) arranged downstream of the first perforated plate fairing when the landing gear is in the deployed condition.

Inventors

• GREEN CHRIS
• Hassan Jawaharar

Assignees

• 赛峰起落架系统英国有限公司

Dates

Publication Date

20260512

Application Date

20240828

Priority Date

20230901

Claims (20)

1. 1. An aircraft landing gear assembly comprising a wheel and brake assembly and a shock strut, the strut comprising a mounting bearing for movably coupling the aircraft landing gear assembly to an aircraft for movement between a stowed condition for flight and a deployed condition for take-off and landing, the aircraft landing gear assembly further comprising: A noise-inducing region; A first perforated plate fairing arranged upstream relative to the noise-inducing area and positioned to influence, in use, airflow proximate the noise-inducing area when the landing gear is in the deployed state, and And a second perforated plate fairing arranged downstream of the first perforated plate fairing when the landing gear is in the deployed state.
2. 2. An aircraft landing gear assembly comprising a wheel and brake assembly and a shock strut, the strut comprising a mounting bearing for movably coupling the aircraft landing gear assembly to an aircraft for movement between a stowed condition for flight and a deployed condition for take-off and landing, the aircraft landing gear assembly further comprising: A noise-inducing region; a first perforated panel fairing arranged downstream relative to the noise-inducing area and positioned to influence, in use, airflow exiting the noise-inducing area when the landing gear is in the deployed state, and And a second perforated plate fairing arranged downstream of the first perforated plate fairing when the landing gear is in the deployed state.
3. 3. An aircraft landing gear assembly according to claim 1, wherein a downstream fairing is arranged upstream of the noise-inducing region when the landing gear is in a deployed state.
4. 4. An aircraft landing gear assembly according to claim 1, wherein a downstream fairing is arranged downstream of the noise-inducing region when the landing gear is in a deployed state.
5. 5. An aircraft landing gear assembly according to any preceding claim, further comprising an intermediate perforated plate fairing arranged downstream with respect to an upstream fairing and upstream with respect to a downstream fairing when the landing gear is in the deployed state.
6. 6. An aircraft landing gear assembly according to any preceding claim, wherein the upstream fairing has a different porosity to the downstream fairing.
7. 7. An aircraft landing gear assembly according to claim 6, wherein the upstream fairing has a higher porosity than the downstream fairing.
8. 8. An aircraft landing gear assembly according to any preceding claim, wherein the shape or shapes of the perforations in the upstream fairing are different to the shape or shapes of the perforations in the downstream fairing.
9. 9. An aircraft landing gear assembly according to any preceding claim, wherein one of the fairings is sized, shaped and positioned to cover only a partial region of the other of the fairings.
10. 10. An aircraft landing gear assembly according to any preceding claim, wherein the porosity level of each fairing is between 30% and 70%.
11. 11. An aircraft landing gear assembly according to any preceding claim, wherein one or more of the perforated plate fairings each comprise a plurality of perforations of a first size and a plurality of perforations of a second size, the second size being different to the first size, and optionally a plurality of perforations of a third size, the third size being different to the first and second sizes, and/or the perforations being evenly distributed.
12. 12. An aircraft landing gear assembly according to any preceding claim, wherein the or each fairing is formed from a plurality of discrete perforated plate elements connected together.
13. 13. An aircraft landing gear assembly according to any preceding claim, wherein the upstream fairing and the downstream fairing are arranged in a parallel arrangement relative to each other.
14. 14. An aircraft landing gear assembly according to any one of claims 1 to 12, wherein the upstream fairing and the downstream fairing are arranged in a non-parallel arrangement relative to each other.
15. 15. An aircraft landing gear assembly according to any preceding claim, wherein the upstream fairing is mounted at a first distance from the noise-inducing area and the downstream fairing is mounted at a second distance from the noise-inducing area, wherein the first and second distances are different.
16. 16. An aircraft landing gear assembly comprising a wheel and brake assembly and a shock strut, the strut comprising a mounting bearing for movably coupling the aircraft landing gear assembly to an aircraft for movement between a stowed condition for flight and a deployed condition for take-off and landing, the aircraft landing gear assembly further comprising: A noise-inducing region; The perforated plate fairing, The perforated cowling being arranged upstream relative to the noise-inducing region and positioned so as to influence, in use, the airflow proximate the noise-inducing region when the landing gear is in the deployed state, or The perforated cowling being arranged downstream relative to the noise-inducing area when the landing gear is in the deployed condition, and positioned so as to influence in use the airflow exiting the noise-inducing area, Wherein the perforated cowling has a sinusoidal cross-section defining a plurality of peaks and a plurality of valleys.
17. 17. An aircraft landing gear assembly according to claim 16, wherein the perforated plate fairing has a sinusoidal cross-section in orthogonal planes.
18. 18. An aircraft landing gear assembly comprising a wheel and brake assembly and a shock strut, the strut comprising a mounting bearing for movably coupling the aircraft landing gear assembly to an aircraft for movement between a stowed condition for flight and a deployed condition for take-off and landing, the aircraft landing gear assembly further comprising: A noise-inducing region; The perforated plate fairing, The perforated cowling being arranged upstream relative to the noise-inducing region and positioned so as to influence, in use, the airflow proximate the noise-inducing region when the landing gear is in the deployed state, or The perforated cowling being arranged downstream relative to the noise-inducing area when the landing gear is in the deployed condition, and positioned so as to influence in use the airflow exiting the noise-inducing area, Wherein the perforated cowling includes a plurality of perforations of a first size and a plurality of perforations of a second size, the second size being different from the first size.
19. 19. The aircraft landing gear assembly of claim 18, wherein the perforated panel fairing includes a plurality of perforations of a third size, the third size being different from the first size and the second size.
20. 20. An aircraft landing gear assembly according to claim 18 or 19, wherein the perforations of the perforated plate fairing are evenly distributed.

Description

Aircraft landing gear assembly Background The aircraft can generate considerable noise during landing. A significant portion of this noise is due to the air flow around the deployed landing gear. Although the speed of an aircraft during landing may be around 80 m/s, the local airflow speed around the noise-inducing area of the landing gear may reach about 300 m/s. Interactions between landing gear and airflow may lead to turbulence, vortex shedding, and boundary layer separation, all of which may lead to increased noise. This is known in the art and is referred to herein as aeroacoustic noise. Aeroacoustic noise is particularly undesirable because airports are often close to cities or other densely populated areas. Attempts have been made to solve the aerodynamic acoustic noise problem. For example, it is known to provide aircraft landing gear with fairings. Fairings are an overall rigid structure, typically made of metal or composite material, arranged to shield noise-inducing areas of the aircraft landing gear from airflow during landing. However, the inventors have found that known noise reducers, such as fairings, can undesirably increase the weight of the landing gear. Surface pressure fluctuations on the landing gear due to turbulence and unsteady aerodynamic forces further exacerbate the challenges of effective noise reduction. Although perforated plate fairings have been proposed for reducing aeroacoustic noise, they may be ineffective in solving problems of flow-induced noise, turbulence, and surface pressure fluctuations. Furthermore, known perforated panel fairings may have limited adaptability to different aircraft configurations and operating conditions, making it difficult to achieve noise reduction performance in a range of situations. Disclosure of Invention According to a first aspect of the present invention there is provided an aircraft landing gear assembly comprising a wheel and brake assembly and a shock strut comprising a mounting bearing for movably coupling the aircraft landing gear assembly to an aircraft for movement between a stowed condition for flight and a deployed condition for take-off and landing, the aircraft landing gear assembly further comprising: A noise-inducing region; a first perforated plate fairing arranged upstream relative to the noise-inducing area and positioned to influence, in use, airflow proximate the noise-inducing area when the landing gear is in the deployed state, and And a second perforated plate fairing arranged downstream of the first perforated plate fairing when the landing gear is in the deployed state. According to a second aspect of the present invention there is provided an aircraft landing gear assembly comprising a wheel and brake assembly and a shock strut comprising a mounting bearing for movably coupling the aircraft landing gear assembly to an aircraft for movement between a stowed condition for flight and a deployed condition for take-off and landing, the aircraft landing gear assembly further comprising: A noise-inducing region; A first perforated panel fairing arranged downstream relative to the noise-inducing area and positioned to influence, in use, airflow exiting the noise-inducing area when the landing gear is in the deployed state, and And a second perforated plate fairing arranged downstream of the first perforated plate fairing when the landing gear is in the deployed state. Accordingly, the claimed invention relates to a noise reduction system for landing gear that utilizes a staggered double perforated fairing configuration operating in series to affect airflow through the noise-inducing area to achieve enhanced turbulence reduction and broadband noise reduction over various frequency ranges. Double perforated cowls may provide significant advantages over single perforated plate cowls because they utilize a variety of noise reduction mechanisms, including aerodynamic and flow related effects. The double perforated fairing arrangement can effectively control the velocity and turbulent kinetic energy of the impinging stream as well as the boundary layer, reduce vortex shedding and dissipate turbulent kinetic energy, thereby minimizing the generation of flow induced noise. Advantageously, the double perforated fairing arrangement enables the distance between the forward and aft perforated fairings to be optimized for a given landing gear and/or operational use. This enables better flow control in terms of velocity and turbulent kinetic energy, so that noise reduction performance can be improved. Thus, by providing enhanced broadband noise reduction performance, effective turbulence reduction, reduced surface pressure fluctuations, and adaptability to different aircraft configurations and operating conditions, the landing gear assembly according to the first and second aspects may effectively address the limitations of the single perforated panel fairing, thereby improving landing gear noise reduction performance and facilitatin