Composite Fitting for Aircraft Horizontal Tail Stabilizer Attachment
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Solution Overview
Problem
Metallic fittings for attaching aircraft horizontal tail stabilizers are prone to fatigue and cracks, leading to complex and costly installations, and can only be mounted during manufacturing, making them unsuitable for existing aircraft.
Innovation Solution
A composite carbon fiber fitting with a U-shaped core piece and reinforcements, designed for external installation on the horizontal tail plane, eliminating fatigue and allowing for easier installation through internal manholes, manufactured as a single unitary piece via cutting, folding, and co-curing in an autoclave.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metallic fittings are used for attaching horizontal tail stabilizers, then the fittings can be manufactured with conventional materials and processes, but the fittings are prone to fatigue and cracks, requiring complex and expensive installations with multiple fittings
Solution Approach 1:
The patent applies composite materials (specifically carbon fiber reinforced plastic - CFRP) to manufacture the fitting, replacing traditional metallic materials. This composite material provides superior resistance to fatigue and cracks while maintaining structural integrity, directly resolving the reliability issue without requiring multiple fittings or complex assemblies
Solution Approach 2:
The patent merges multiple separate metallic fittings into a single integrated composite fitting structure. This unified design eliminates the need for multiple discrete components and their associated fasteners, thereby reducing installation complexity while improving reliability through the fatigue-resistant composite material
2Adaptability or versatility
If metallic fittings are installed during aircraft manufacturing, then the fittings can be properly integrated into the structure, but the fittings cannot be installed in already manufactured aircraft
Solution Approach 1:
The patent segments the fitting installation process from the aircraft manufacturing process, designing the composite fitting as a standalone component that can be installed independently. The fitting includes integrated fastening features that allow attachment to the horizontal tail plane through existing access points, enabling installation on existing aircraft without requiring disassembly of the entire aircraft structure
Solution Approach 2:
Instead of installing the fitting from the interior of the aircraft during manufacturing, the patent enables installation from the exterior through access panels. This inverted installation approach allows retrofitting of existing aircraft by accessing the mounting location through existing manholes or panels, eliminating the constraint that fittings could only be installed during initial manufacturing
3Weight of moving object
If composite carbon fiber fittings are used, then the fittings are lighter and have no fatigue failure mode, but the manufacture of composite components is complex and more expensive
Solution Approach 1:
The patent utilizes carbon fiber reinforced plastic (CFRP) composite materials to manufacture the fitting, achieving significant weight reduction compared to metallic alternatives. The composite material provides high strength-to-weight ratio while eliminating fatigue failure modes, directly addressing the weight reduction goal despite the inherent complexity of composite manufacturing processes
4Strength
If multiple metallic fittings are assembled to attach horizontal tail stabilizers, then the attachment can be achieved, but the installation becomes complex and expensive
Solution Approach 1:
The patent combines multiple separate metallic fittings and fasteners into a single integrated composite fitting structure. This unified design maintains the required attachment strength for horizontal tail stabilizers while eliminating the complexity of assembling multiple discrete components, directly reducing both the number of parts and installation complexity
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 composite fitting reduces installation time, eliminates fatigue-related issues, and can be installed on both new and existing aircraft, offering a lighter, cost-effective solution with longer inspection intervals.
Implementation Method 1
co-curing in autoclave
Implementation Method 2
co-curing in autoclave
Data Source
Figure 1a~1c
Figure 2~4
AI summary
Fitting for attaching the horizontal tail stabilizer of an aircraft, allowing to obtain a lighter component, without fatigue failure mode and with a significant reduction in the installation time, wherein the fitting comprises: - a core piece (1) having a regular thickness, the core piece (1) having U configuration, according to a plan view, thereby being composed by two lateral areas (1') and a central area (1") located between the arm areas (1'), - at least one central reinforcement (2) having a regular thickness and joined to one side of the central area (1") and comprising a flange (2') located in an inner edge (1"') of the core piece (1), - at least two lateral reinforcements (3) having a regular thickness and each lateral reinforcement (3) being joined to one side of a different lateral area (1') and comprising a flange (3') located in the inner edge (1"') of the core piece (1).