Fairing Assembly Wing-Body Interface Thermal Management

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Solution Overview

Problem

Winged launch vehicles and hypersonic vehicles face challenges in designing fairings due to thermal and elastic strains causing relative deflections, which complicate the management of differential growth at wing-body interfaces, and existing sealing concepts are not designed to handle large relative movements or high temperatures effectively.

Innovation Solution

A fairing assembly with a substructure coupled to the tank skin, a thermal protection system, and a seal assembly that overlaps the wing edge, allowing for relative motion while maintaining a smooth outer mold line and providing thermal protection up to 1700 degrees Fahrenheit, using materials like ceramic tiles and metallic superalloys for the substructure and seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature seals are used to prevent airflow from entering internal cavities, then sealing effectiveness is improved, but the seals cannot function between surfaces with large amounts of relative movement

Engineering Contradiction:
Improvesealing effectivenessVSAvoidability to handle relative movement
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The seal assembly is designed with a compliant seal element that can dynamically adapt to relative movements between the fairing and wing. The seal element is mounted on a support structure that allows it to move and deform, maintaining sealing contact despite differential growth and thermal expansion. This dynamic design enables the seal to function effectively under varying thermal and mechanical conditions while accommodating large relative movements.

Inventive Principle:
Principle #15Dynamics

2Temperature

If the outer surfaces of fairings are designed to withstand temperatures up to 926 degrees Celsius with smooth surfaces, then aerodynamic performance is improved, but the complexity of the thermal protection system increases

Engineering Contradiction:
Improvethermal resistanceVSAvoidthermal protection system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The fairing incorporates a composite thermal protection system combining ceramic tiles bonded to the outer surface with a refractory mortar layer. This composite structure provides the necessary thermal resistance to withstand temperatures up to 926 degrees Celsius while maintaining a smooth aerodynamic surface. The ceramic tiles offer high-temperature durability, while the mortar matrix binds them together and fills gaps, creating an integrated thermal barrier that protects the underlying structure.

Inventive Principle:
Principle #40Composite materials

3Stability of the object's composition

If thermal and elastic strains are allowed to cause relative deflections in wing and body, then structural flexibility is improved, but the design of fairings at wing to body interfaces becomes complicated

Engineering Contradiction:
Improvestructural flexibilityVSAvoidfairing design complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The fairing structure is segmented into modular components including a fairing skin, support structure, and seal assembly. This segmentation allows each component to independently accommodate thermal and elastic strains. The support structure includes struts and brackets that can flex, while the seal assembly is positioned to accommodate relative movements between segmented sections, simplifying the overall design by distributing the accommodation of differential growth across multiple independent elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The seal assembly acts as an intermediary element between the fairing and wing structures. It is positioned at the interface where relative movements occur and provides a compliant connection that accommodates differential growth. The seal assembly includes a compliant seal element mounted on a support structure that can deform and move, mediating the interaction between the fairing and wing while maintaining sealing effectiveness despite relative deflections.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If conventional fairings are attached with fasteners between two adjacent structures, then ease of manufacture is improved, but the structures cannot be designed to move relative to each other

Engineering Contradiction:
Improvefairing attachment simplicityVSAvoidrelative movement capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention replaces rigid mechanical fastener connections with a compliant seal element mounted on a flexible support structure. Instead of using rigid fasteners that prevent relative movement, the seal assembly uses compliant materials and flexible mounting brackets that allow the fairing and wing to move relative to each other while maintaining the sealing function. This substitution enables relative movement capability while preserving the ease of manufacture through simplified attachment procedures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution effectively manages relative growth between the wing and body, prevents airflow into internal cavities, maintains a smooth aerodynamic surface, and provides thermal protection, enabling efficient operation of winged launch vehicles and hypersonic vehicles.

Implementation Method 1

launch vehicles typically require some type of thermal protection system to reduce the temperatures of underlying structures to an acceptable range

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

fairings generally include a high-temperature perimeter edge seal that is compressed upon installation

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

thermal and elastic strains in the wing and body induced during operation result in large relative deflections

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3444192B1Fairing assembly and method therefor
Publication Date: 2021.05.12 THE BOEING CO
  • EP3444192B1 patent drawingFigure 1~2
  • EP3444192B1 patent drawingFigure 3
  • EP3444192B1 patent drawingFigure 4

AI summary

A fairing assembly (114A) for an aerial vehicle (100) having a tank (202) that forms a body (110) of the vehicle and a wing (112) coupled to the tank is provided. The fairing assembly includes a substructure (164) configured to couple with a tank skin (378) of the tank, a thermal protection system (190) coupled to the substructure, and a seal assembly (192) coupled to the substructure, the seal assembly being configured to overlap at least a portion of an edge (118) of the wing.