Noise Reduction Fairing for Aircraft Landing Gear Brake Assemblies

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Solution Overview

Problem

Aircraft landing gear generates significant noise during take-off and landing due to turbulent airflow, particularly over brake assemblies with complex geometry, and existing fairings either accelerate airflow or become blocked by debris, leading to increased noise.

Innovation Solution

A noise reduction fairing that provides localized shielding for the brake assembly or electric drive system using a composite material with metallic inserts and a temperature-resistant coating, configured to occupy minimal space and allow sufficient cooling, with multiple attachment points for secure attachment and minimal modification to existing landing gear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a single large-size fairing is provided on the landing gear to cover the entire area between wheels, brakes and torque links, then noise from turbulent airflow over landing gear elements is reduced, but airflow is accelerated over the fairing which strikes downstream surfaces and generates further noise

Engineering Contradiction:
Improvenoise from turbulent airflowVSAvoidnoise from accelerated airflow striking downstream surfaces
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent divides the landing gear assembly into multiple discrete fairing elements positioned at specific locations around individual components (wheels, brakes, torque links) rather than using one large fairing. This segmentation prevents the creation of a large accelerated airflow zone that would strike downstream surfaces, while still providing noise reduction at each component location.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies fairings locally to specific noise-generating components rather than covering the entire landing gear area. Each fairing is designed to address the aerodynamic characteristics of its specific location, providing targeted noise reduction without creating the broad accelerated airflow pattern that causes downstream noise.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If perforations or mesh membranes are included in the fairing to allow airflow passage at reduced velocity, then noise from accelerated airflow is reduced, but the perforations and mesh areas become blocked with dust or debris and fail to function as intended

Engineering Contradiction:
Improvenoise from accelerated airflowVSAvoidairflow passage functionality
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent removes the perforations and mesh membranes from the fairing design entirely. Instead, the fairing is designed as a solid structure with optimized geometry that naturally manages airflow without requiring openings, thereby eliminating the reliability issue of clogging while still achieving noise reduction through proper aerodynamic shaping.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of stationary object

If the fairing is configured to shield only the portion of the brake assembly or electric drive system subject to direct air flow, then noise reduction is achieved with minimal space occupation, but the remaining exposed portion must provide sufficient cooling within acceptable time period

Engineering Contradiction:
Improvespace occupied by fairingVSAvoidbrake cooling effectiveness
Core Design Contradiction:
Volume of stationary objectVSTemperature

Solution Approach 1:

The patent configures the fairing to provide shielding only where direct airflow causes noise, while leaving portions of the brake assembly exposed for cooling. The fairing geometry is specifically designed to create acoustic shielding in the noise-generating zones while maintaining thermal management pathways for brake cooling, achieving both noise reduction and temperature control.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The fairing effectively reduces noise by minimizing airflow acceleration and debris accumulation while maintaining adequate cooling and structural integrity, allowing for retrofitting without additional costs or weight penalties.

Implementation Method 1

This noise is generated by the turbulent airflow passing over and through the constituent elements of the landing gear when the landing gear is down

Methodology Applied
Scientific EffectTurbulent airflow: Turbulence

Implementation Method 2

the fairing being designed to deflect the airflow both around the brakes and other adjacent components of the landing gear

Methodology Applied
Scientific EffectAirflow deflection:

Implementation Method 3

a result of deflecting the airflow is that the airflow is accelerated over the fairing. When this accelerated airflow strikes other solid surfaces of the landing gear located downstream of the fairing this in turn generates further noise

Methodology Applied
Scientific EffectAirflow acceleration:

Implementation Method 4

The intended function of these mesh areas or perforations is to allow some airflow to pass through the fairing but at a reduced velocity

Methodology Applied
Scientific EffectFlow through perforations:

Implementation Method 5

The composite material preferably includes a temperature resistant resin. Additionally or alternatively the fairing includes a ceramic coating. The use of a high temperature resistant resin and/or a temperature resistance ceramic coating enables the fairing to withstand the high temperatures that occur during operation of the brakes

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Data Source

PatentEP3560826B1Noise reduction fairing
Publication Date: 2022.11.30 MESSIER DOWTY
  • EP3560826B1 patent drawingFigure 1~2
  • EP3560826B1 patent drawingFigure 3
  • EP3560826B1 patent drawingFigure 4A~5B

AI summary

An aircraft landing gear assembly including a plurality of noise-inducing elements, at least one of the noise-inducing elements comprising a brake assembly or electric drive assembly, and a noise reduction fairing arranged to shield only at least a portion of the brake assembly from incident airflow.