Dual-Seal Aircraft Hinge Assembly for Drag and Leakage Control
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Solution Overview
Problem
Aircraft wing tip devices with folding mechanisms face aerodynamic penalties due to small steps or gaps between the wing and the tip, leading to drag and pressure leakage, and existing seal solutions are difficult to integrate with complex surfaces and harsh environments.
Innovation Solution
A hinge assembly with two seal assemblies, one for the aerodynamic surface and another for the underside, featuring interposed fingers and resilient flexible strips, which maintain the aerodynamic profile while allowing flexible movement and sealing voids, reducing pressure leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a seal is introduced to maintain aerodynamic profile, then aerodynamic drag is reduced, but the seal assembly becomes more complex and difficult to integrate
Solution Approach 1:
The seal assembly is divided into multiple segments corresponding to individual hinge fingers. Each seal segment is independently mounted on its respective finger, allowing the complex sealing function to be broken down into manageable, repeatable units that are easier to integrate into the hinge structure.
Solution Approach 2:
The seal profile is customized for each specific location along the hinge assembly. Each seal segment has a tailored cross-sectional shape and mounting configuration suited to its local aerodynamic requirements and structural constraints, rather than using a uniform seal design throughout.
2Loss of energy
If a rigid seal is used to maintain aerodynamic profile, then aerodynamic performance is improved, but the seal cannot accommodate movement between flight and ground configurations
Solution Approach 1:
The seal incorporates flexible elements such as elastomeric lips and thin-walled structures that can bend and deform as the hinge moves between flight and ground configurations. These flexible components maintain aerodynamic sealing during flight while accommodating the mechanical range of motion required for folding operations.
Solution Approach 2:
The seal design transitions from a static, rigid structure to a dynamic system that adapts its shape and position during movement. The flexible seal components actively respond to changes in hinge angle and loading conditions, maintaining aerodynamic effectiveness across the full range of motion.
3Reliability
If seal material is made resilient to withstand harsh environment, then reliability is improved, but the seal becomes stiffer and harder to integrate with complex surfaces
Solution Approach 1:
The seal employs composite construction combining resilient elastomeric materials for environmental resistance with flexible structural supports. This composite approach allows the seal to withstand harsh aerodynamic and environmental conditions while maintaining the flexibility needed for integration with complex hinge geometries.
Solution Approach 2:
The seal design utilizes three-dimensional profiling and multi-layer construction to achieve both resilience and flexibility. By adding dimensional complexity in the form of curved lips, tapered profiles, and layered structures, the seal can simultaneously resist environmental degradation and adapt to complex surface geometries.
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 dual-seal hinge assembly effectively reduces aerodynamic drag and pressure leakage by maintaining the wing's aerodynamic profile and sealing gaps, ensuring efficient operation in both flight and ground configurations.
Implementation Method 1
A seal assembly comprising a first seal assembly arranged to seal between the aerodynamic surfaces of the hinge plates and a second seal assembly arranged to seal between the undersides of the plates
Data Source
AI summary
A hinge assembly 8a for an aircraft component including first and second hinge plates 9, 10, having an aerodynamic surface. A first seal assembly 28 to 32 is provided and arranged to seal between the aerodynamic surfaces of the hinge plates. A second seal assembly 38 to 42 is arranged to seal between the undersides of the hinge plates in order to reduce pressure leakage between voids under the hinge. The provision of two seal assemblies, each having a dedicated function, addresses the competing demands made on the sealing arrangement of an aircraft hinge assembly in use.