Aircraft Central Fairing Geometric Deformations for Drag Reduction

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Solution Overview

Problem

Remotorization of aircraft to accommodate larger engines leads to degradation of aerodynamic performance, necessitating improvements without compromising wing structures or increasing weight or manufacturing costs.

Innovation Solution

The central fairing is modified with local geometric deformations on its surfaces to generate aerodynamic perturbations, such as expansion and compression waves, which control airflow over the wing, reducing drag without significant weight or cost changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If larger engines are installed to increase autonomy and useful load, then the engine power and autonomy are improved, but the aerodynamic performance of the aircraft deteriorates

Engineering Contradiction:

Improveengine powerVSAvoidaerodynamic drag

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent applies local geometric deformations to specific zones of the central fairing surface rather than modifying the entire structure. These localized deformations create targeted aerodynamic perturbations that control airflow over the wing, reducing wave drag while maintaining the large engine installation for increased power and autonomy.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies the geometric parameters of the central fairing by introducing local deformations with specific curvatures and radii. These parameter changes in the fairing geometry generate pressure waves that propagate over the wing, optimizing airflow and reducing aerodynamic drag without changing the engine size.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If special geometric shaping is added to the central fairing to control airflow, then aerodynamic performance is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improveaerodynamic dragVSAvoidmanufacturing complexity

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent introduces local geometric deformations at specific zones of the central fairing rather than requiring complex shaping throughout the entire structure. This localized approach simplifies manufacturing by concentrating geometric complexity only where aerodynamically necessary, while keeping the rest of the fairing design simple and straightforward to manufacture.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If the local radius of curvature is reduced to create geometric deformations, then aerodynamic perturbations are generated, but the structural strength may be compromised

Engineering Contradiction:

Improvewave dragVSAvoidstructural strength

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The patent applies geometric deformations with reduced local radius of curvature only to specific zones of the central fairing surface. These localized deformations are designed to generate necessary aerodynamic perturbations while maintaining sufficient structural strength through appropriate deformation magnitude and positioning that does not compromise the overall structural integrity.

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

This solution enhances aerodynamic performance under various flying conditions and improves airflow management, reducing wave drag and maintaining structural integrity and manufacturing efficiency.

Implementation Method 1

the fairing conformed in this way is capable of acting favorably on the airflow of the wing structure by generating pressure waves that propagate in the direction of the free tip of the wing in question

Methodology Applied

Scientific EffectPressure waves: Shock Wave

Implementation Method 2

The pressure waves generated by one or more deformed zones of the surface in question may be expansion waves, compression waves or a combination of the two

Methodology Applied

Scientific EffectExpansion waves: Shock Wave

Implementation Method 3

The pressure waves generated by one or more deformed zones of the surface in question may be expansion waves, compression waves or a combination of the two

Methodology Applied

Scientific EffectCompression waves: Shock Wave

Data Source

PatentUS8177170B2Aircraft comprising a central fairing that adjusts the pressure on the wing structures by means of local geometric deformations

Publication Date: 2012.05.15 AIRBUS OPERATIONS (SAS)

AI summary

An aircraft including: a fuselage and two wings to which engine nacelles are attached and that are each connected laterally to the fuselage, one on each side thereof, by a central fairing. The central fairing includes, facing each wing, two opposed surfaces connected one to a suction face side and the other to a pressure face side of the wing and that extend longitudinally along the fuselage. At least one of the two surfaces includes at least one local geometric deformation configured to generate lateral aerodynamic disturbances on the central fairing toward the wing to control the flow of air over the wing.