Composite Wing Body With Internal Fastening For Laminar Flow

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Solution Overview

Problem

Commercial aircraft wings experience turbulent boundary layers due to shape deviations and rivet connections, leading to increased drag and fuel consumption, while conventional designs are not easily repairable and weigh heavily, posing safety and economic challenges.

Innovation Solution

A wing body design featuring a wing box formed from diametrically opposed wing shells made of fiber composite materials, with internal fastening elements connecting the wing leading edge to the wing shells without penetrating the flow surface, promoting a laminar boundary layer and allowing for replaceable leading edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rivet connections are used to attach the leading edge to the wing box, then structural strength and reliability are improved, but the flow surface is disturbed causing transition from laminar to turbulent boundary layer increasing drag

Engineering Contradiction:
Improvestructural strengthVSAvoiddrag
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The fastening elements are extracted from the flow surface and relocated to the interior of the wing box structure. The leading edge is attached to internal structural elements (spars, ribs, or frame) rather than using external rivets on the flow surface, thereby removing the source of flow disturbance while maintaining structural connection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The attachment system is moved from a two-dimensional surface connection (rivets on the exterior flow surface) to a three-dimensional interior connection (fastening elements within the wing box structure). This dimensional transition allows structural attachment without compromising the laminar flow quality of the external surface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If the wing body is formed integrally, then the flow surface is free of disturbances promoting laminar flow, but the leading edge becomes non-replaceable and the entire wing must be replaced upon damage

Engineering Contradiction:
ImprovedragVSAvoidleading edge replaceability
Core Design Contradiction:
Loss of energyVSEase of repair

Solution Approach 1:

The wing body is segmented into modular components: the leading edge is a separate replaceable component that can be attached to or detached from the main wing box structure. This segmentation allows the leading edge to be replaced independently without replacing the entire wing, while maintaining a smooth flow surface through proper design of the attachment interface.

Inventive Principle:
Principle #1Segmentation

3Strength

If conventional aluminum materials and riveted joints are used, then structural strength and damage resistance are ensured, but the weight of the wing body increases leading to higher fuel consumption

Engineering Contradiction:
Improvestructural strengthVSAvoidwing weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The wing body utilizes composite materials (such as carbon fiber reinforced polymers) instead of conventional aluminum alloys. These composite materials provide equivalent or superior structural strength and damage resistance while significantly reducing the weight of the wing body, thereby lowering fuel consumption and improving overall aircraft efficiency.

Inventive Principle:
Principle #40Composite materials

4Loss of energy

If shape deviations such as gaps and steps are avoided in the profile surface, then the boundary layer stability is improved extending laminar flow area, but manufacturing complexity and precision requirements increase

Engineering Contradiction:
ImprovedragVSAvoidprofile surface precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The leading edge and wing box structure are merged into an integrated assembly with carefully designed attachment interfaces. The fastening elements are positioned and configured to minimize or eliminate steps and gaps at the junction between the leading edge and the wing box, thereby maintaining profile surface continuity and stability of the boundary layer while allowing for practical manufacturing and assembly processes.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2712803B1Wing body
Publication Date: 2016.05.18 AIRBUS OPERATIONS LTD
  • EP2712803B1 patent drawingFigure 1
  • EP2712803B1 patent drawingFigure 2

AI summary

The invention relates to a wing body (1) for a flying object with a wing box (2) and a wing leading edge (3), wherein the wing shells (4a) forming the wing box are made of a fiber composite material and the wing shell (4a) and the wing leading edge (3) are connected to each other by internal connecting elements (11) to form a flow profile.