Aircraft Window Frame Assembly Sealing Honeycomb Fuselage

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Solution Overview

Problem

Window assemblies in aircraft with honeycomb fuselage skins face challenges in sealing and moisture ingress, requiring effective sealing and weight reduction while maintaining structural integrity and visual access.

Innovation Solution

A window frame assembly with removably attachable spring clips and locking members, such as saw tooth grooves and angled tabs, that provide a sealed barrier and absorb impact without fasteners, bonded to the honeycomb structure for homogenous load distribution and moisture prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If honeycomb fuselage skins are used to reduce aircraft weight, then weight is reduced, but sealing and moisture ingress prevention become more difficult

Engineering Contradiction:

Improveaircraft weightVSAvoidsealing effectiveness

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The window assembly is bonded to the honeycomb structure before final cure, creating a sealed barrier in advance that prevents moisture ingress into the honeycomb core. This preliminary sealing action addresses the sealing difficulty inherent in honeycomb structures while maintaining the weight reduction benefits.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A bonding adhesive serves as an intermediary between the window frame and the honeycomb structure, creating a homogeneous load distribution path and sealing interface. This intermediary bonding layer resolves the contradiction by providing both structural attachment and moisture barrier functions.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If window assemblies are installed in honeycomb fuselage skins after final cure, then installation is simplified, but moisture ingress and sealing challenges increase

Engineering Contradiction:

Improveinstallation simplicityVSAvoidmoisture ingress

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The bonding process is performed before final cure of the honeycomb structure, establishing the seal in advance. This timing allows the window assembly to be integrated into the structure while the adhesive is still workable, simplifying installation while simultaneously addressing moisture prevention.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The uncured state of the honeycomb structure during bonding is converted from a potential vulnerability into an advantage, allowing the adhesive to penetrate and bond more effectively to the honeycomb cells, creating superior sealing and structural attachment.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Weight of moving object

If spring clips with locking members are used instead of fasteners, then weight is reduced, but attachment reliability must be maintained

Engineering Contradiction:

Improvewindow assembly weightVSAvoidattachment strength

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

Traditional mechanical fasteners are replaced with spring clips that utilize elastic deformation and geometric interlocking (saw tooth grooves with angled tabs) to achieve attachment. This substitution reduces weight while maintaining attachment strength through elastic recovery and mechanical interlocking mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The spring clips incorporate dynamic elastic elements that can deform under load and recover, providing continuous contact force and maintaining attachment reliability. The angled tabs engage with the saw tooth grooves to prevent disengagement while allowing controlled deformation.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8087615B2Window installation method

Publication Date: 2012.01.03 THE BOEING CO

AI summary

A particular method includes installing a window assembly in a structure by coupling a window frame body of the window assembly to a first surface of an interior side of an outer skin of the structure. The method also includes coupling the window frame body to a second surface of an interior side of an inner skin of the structure. The method also includes coupling the window frame body to a portion of the structure between the outer skin and the inner skin.