Nose Landing Gear Torque Arm Forward Positioning for Noise Reduction

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Solution Overview

Problem

Conventional nose landing gear arrangements generate significant noise during aircraft approach and landing due to the interaction of airflow with the torque arm assembly, which is located rearward of the shock strut, leading to turbulence and increased noise levels.

Innovation Solution

The torque arm assembly is positioned forward of the shock strut, with a streamlined configuration to shield the shock strut from airflow and reduce wind resistance, thereby minimizing noise generation. This arrangement also includes a wider torque arm that acts as a shield to divert airflow and reduce noise-causing interactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the torque arm assembly is located to the rear of the shock strut, then the conventional arrangement is simple to implement, but the airflow turbulence immediately impacts the torque arm assembly generating loud noise

Engineering Contradiction:
Improveease of assemblyVSAvoidnoise generation
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional arrangement by positioning the torque arm assembly forward of the shock strut instead of rearward. This reversal changes the airflow interaction sequence, allowing the torque arm to encounter undisturbed airflow first, thereby reducing noise generation while maintaining structural simplicity

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-generated harmful factors

If the torque arm assembly is positioned forward of the shock strut with streamlined configuration, then the noise generation is reduced, but the device complexity increases

Engineering Contradiction:
Improvenoise generationVSAvoidstructural complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The torque arm assembly is given a streamlined, curved configuration rather than a straight rigid structure. This aerodynamic shaping reduces turbulence and noise while the modular construction with hinges and adjustable components maintains ease of assembly, balancing complexity reduction with noise mitigation

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Loss of energy

If a wider torque arm is used to shield the shock strut, then the wind resistance is reduced, but the weight of the landing gear increases

Engineering Contradiction:
Improvewind resistanceVSAvoidlanding gear weight
Core Design Contradiction:
Loss of energyVSWeight of moving object

Solution Approach 1:

The torque arm assembly uses a wider but thinner, more aerodynamic cross-section that acts as a streamlined shield. This configuration reduces wind resistance and turbulence without proportionally increasing weight, as the streamlined shape is more efficient at deflecting airflow compared to a bulkier traditional design

Inventive Principle:
Principle #30Flexible shells and thin films

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 new nose landing gear arrangement significantly reduces noise levels during landing by minimizing airflow interactions with the torque arm assembly and shock strut, resulting in lower wind resistance and noise generation compared to conventional designs.

Implementation Method 1

The torque arm assembly is positioned forward of the shock strut, with a streamlined configuration to shield the shock strut from airflow and reduce wind resistance

Methodology Applied
Scientific EffectAerodynamic shielding: Aerofoil

Implementation Method 2

Airflow passing over the shock strut during landing sheds turbulence which then immediately impacts the torque arm assembly

Methodology Applied
Scientific EffectTurbulence reduction: Turbulence

Data Source

PatentEP2746154B1Nose landing gear arrangement for aircraft and method of assembly
Publication Date: 2019.09.11 GULFSTREAM AEROSPACE CORP
  • EP2746154B1 patent drawingFigure 1
  • EP2746154B1 patent drawingFigure 2~3
  • EP2746154B1 patent drawingFigure 4

AI summary

A nose landing gear arrangement (10) for an aircraft and a method of assembling the nose landing gear arrangement (10) are disclosed herein. The nose landing gear arrangement (10) includes a wheel assembly (14), a shock strut (12) extending upwards from the wheel assembly (14) towards a fuselage of the aircraft, and a torque arm assembly (16) coupled to the wheel assembly (14) and to the shock strut (12). The torque arm assembly (16) is configured to transmit torque to the wheel assembly (14). The torque arm assembly (16) is disposed forward of the shock strut (12) with respect to a direction of travel of the aircraft.