Overhanging Composite Trailing Edge Cover for Aircraft

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Solution Overview

Problem

Traditional aircraft wing designs with metallic or composite upper panels attached to the trailing edge using bolts and butt straps result in weight inefficiencies, aerodynamic drag, high manufacturing costs, and limitations in load distribution due to material differences and thermal expansion issues, as well as a complex part count and tooling requirements.

Innovation Solution

A composite cover with an overhanging portion featuring ramps that reduce thickness in a span-wise and/or chord-wise direction, allowing for extended coverage and integration with a hinge rib to pivotally connect aerodynamic control elements, thereby transferring loads more effectively into the cover rather than the rear spar, reducing the need for additional panels and fasteners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If traditional bolted panels and butt straps are used to cover the trailing edge, then structural coverage is achieved, but weight increases and manufacturing complexity increases

Engineering Contradiction:

Improvepanel weightVSAvoidpart count

Core Design Contradiction:

Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent merges the trailing edge cover panel and the wing cover into a single integrated composite structure. This eliminates the need for separate panels, butt straps, and multiple bolts, directly reducing part count and weight while maintaining structural coverage of the trailing edge.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated composite cover serves multiple functions simultaneously: it provides aerodynamic surface coverage, structural reinforcement at the trailing edge, and load transfer pathways. This multi-functionality eliminates the need for separate structural and aerodynamic components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If multiple bolts and butt straps are used for panel attachment, then structural connection is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvemanufacturing costVSAvoidattachment strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

By integrating the panel and wing cover into one composite structure, the patent eliminates numerous bolted connections and butt straps. This reduces manufacturing steps, tooling requirements, and assembly time while maintaining or improving attachment strength through continuous composite material pathways.

Inventive Principle:

Principle #5Merging (Combining)

3Weight of moving object

If panel thickness variations are accommodated by differing bolt grip lengths, then attachment flexibility is achieved, but weight optimization is compromised

Engineering Contradiction:

Improveoverall weightVSAvoidthickness variation accommodation

Core Design Contradiction:

Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent uses ramp features that gradually change the thickness parameter of the composite cover from the root to the tip. This allows the structure to adapt to varying thickness requirements while maintaining optimal weight, as the ramp geometry can be precisely controlled during composite manufacturing without requiring different bolt grip lengths.

Inventive Principle:

Principle #35Parameter changes

4Object-affected harmful factors

If countersunk bolts are used for panel attachment, then aerodynamic surface fairness is improved, but drag increases due to raised or recessed heads

Engineering Contradiction:

Improveaerodynamic dragVSAvoidcountersunk head alignment

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent extracts and eliminates the bolted connection system entirely from the trailing edge assembly. By using an integrated composite structure, there are no countersunk heads, raised surfaces, or recessed features that would disrupt the aerodynamic flow and create drag.

Inventive Principle:

Principle #2Taking out (Extraction)

5Strength

If traditional panel design is used to accommodate sympathetic wing bending stresses, then structural integrity is maintained, but the cover overhang cannot react significant aerodynamic control element loads

Engineering Contradiction:

Improvecover overhang strengthVSAvoidcover overhang length

Core Design Contradiction:

StrengthVSLength of moving object

Solution Approach 1:

The patent employs composite materials for the integrated cover structure, providing high strength-to-weight ratio and design flexibility. The composite construction allows the cover overhang to be extended further aft while maintaining the strength required to react significant aerodynamic control element loads, overcoming the limitations of traditional metallic panels.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS8113465B2Trailing edge aircraft structure with overhanging cover

Publication Date: 2012.02.14 AIRBUS OPERATIONS LTD

AI summary

An aircraft structure comprising: a rear spar; and a composite cover attached to the rear spar and having an overhanging portion extending to its rear. The overhanging portion of the cover comprises one or more ramps along which the thickness of the cover reduces. A second cover is attached to the rear spar and overhangs to its rear. A hinge rib is attached to one or both of the covers, and an aerodynamic control element such as an aileron, rudder or elevator is pivotally mounted to the hinge rib.