Dovetail Aircraft Windscreen Attachment for Thermal Expansion

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Solution Overview

Problem

Aircraft windscreens are prone to failure due to differential expansion and contraction of materials under varying environmental conditions, leading to excessive stress and structural loads, especially when attached with conventional fasteners that do not allow for adequate play, resulting in cracking, breaking, or detachment from the fuselage.

Innovation Solution

A dovetail-shaped portion is formed around the periphery of the windscreen, which is seated in a channel created by a retaining member and the fuselage, eliminating the need for through holes and allowing for differential expansion while providing a secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fasteners are used to attach the windscreen to the fuselage, then the windscreen is securely attached, but the windscreen is prone to failure due to differential expansion and contraction

Engineering Contradiction:

Improvewindscreen attachment reliabilityVSAvoidwindscreen structural strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The attachment system transitions from a rigid fixed connection to a dynamic system that accommodates movement. The dovetail-shaped portion allows the windscreen to expand and contract independently within the channel, providing play that absorbs differential thermal expansion and contraction between the glass/acrylic windscreen and the aluminum fuselage, preventing stress buildup and failure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The attachment system is divided into separate functional components: the dovetail-shaped portion integrated with the windscreen, the channel structure, and the retaining member. This segmentation allows each component to perform its specific function - the dovetail provides expansion space, the channel guides movement, and the retaining member secures the assembly - while working together to solve the thermal expansion problem

Inventive Principle:

Principle #1Segmentation

2Reliability

If through holes are formed in the windscreen for fasteners, then the windscreen can be attached to the fuselage, but the holes reduce the overall strength and create points of potential failure

Engineering Contradiction:

Improvewindscreen attachment reliabilityVSAvoidwindscreen structural strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The fastener attachment method is extracted and relocated from the windscreen itself to a separate retaining member. The retaining member, which is attached to the fuselage with fasteners, engages with the dovetail-shaped portion of the windscreen. This removes the need for holes in the windscreen, preserving its structural integrity while still achieving secure attachment through the external retaining member mechanism

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If the windscreen is rigidly attached to the fuselage, then secure attachment is achieved, but excessive stress builds up due to material expansion and contraction

Engineering Contradiction:

Improveattachment securityVSAvoidthermal stress

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The attachment system changes the mechanical parameters of the connection from rigid to semi-rigid. The dovetail geometry and channel design allow for controlled movement and play, changing the stiffness parameter to accommodate thermal expansion and contraction. This reduces thermal stress buildup while maintaining sufficient attachment security through the retaining member that engages with the fuselage structure

Inventive Principle:

Principle #35Parameter changes

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 ensures a secure attachment of the windscreen to the fuselage while accommodating material expansion and contraction, reducing the risk of failure and maintaining an airtight seal, thus enhancing the structural integrity and durability of the windscreen.

Implementation Method 1

the different materials may have differing coefficients of expansion and/or may experience different degrees of expansion and/or contraction under various changing conditions, e.g., resulting from temperature differentials arising due to changes in altitude during aircraft flight

Methodology Applied

Scientific EffectDifferential thermal expansion: Thermal Expansion

Implementation Method 2

Further expansion and/or contraction of the differing construction materials can result due to changes in the air pressures experienced at varying altitudes

Methodology Applied

Scientific EffectPressure-induced expansion:

Data Source

PatentUS10538305B2Dovetail aircraft windscreen

Publication Date: 2020.01.21 TYSON VALDEZ LLC

AI summary

An aircraft windscreen (100) includes: a main body; and a dovetail shaped portion (120) formed in the main body at a periphery thereof. Suitably, the windscreen (100) is secured within an opening (192) of an aircraft frame or body (190). In this regard, the aircraft has: a body (190) constructed of a first material and including an opening (192) therein; a windscreen (100) constructed of a second material and arranged within the opening (192) of the body (190); and a retaining member (400) attached to the body (190) and/or fuselage (300) by a set of fasteners (402) so as to secure the windscreen (100) thereto. Suitably, the retaining member (400) cooperates with the body and/or fuselage (300) to form a channel (200) in which a dovetailed shaped portion (120) formed at a periphery of the windscreen (100) is seated so as to be retained without through holes being formed in the windscreen (100).