Dielectric Nut Retainer Strip for Lightning-Safe Wing Fasteners
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Solution Overview
Problem
Aerospace vehicle manufacturers face challenges in providing lightning protection for composite components, particularly in thin wings where access to fasteners is difficult, and existing solutions either add weight and drag or are not easily removable.
Innovation Solution
A fastening system using a dielectric nut retainer strip with anti-rotation features, caps, and conductive coatings, which allows for electrical isolation and easy removal of fasteners while maintaining structural integrity and minimizing weight and drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If access panels are added to allow inspection and removal of fasteners, then ease of operation is improved, but weight and drag increase
Solution Approach 1:
The patent merges the fastener head and access features directly into the aerodynamic surface of the wing, eliminating the need for separate access panels. The fastener heads are exposed on the upper surface, allowing inspection and removal without additional panels, thus maintaining ease of operation while reducing weight and drag.
Solution Approach 2:
The patent extracts the access panel function from the wing structure and integrates it directly into the fastener design. By making fastener heads accessible on the upper surface, the patent removes the need for separate access panels, achieving both weight reduction and maintained operability.
2Ease of operation
If access panels are added to allow inspection and removal of fasteners, then ease of operation is improved, but drag increases
Solution Approach 1:
The patent merges the access function with the aerodynamic surface by exposing fastener heads on the upper surface. This integration eliminates separate access panels that would create drag, while maintaining ease of operation for inspection and removal.
Solution Approach 2:
The patent extracts the access panel function and integrates it into the fastener design itself. By making fastener heads accessible on the upper surface, the patent removes the need for additional panels that would increase drag, achieving both reduced drag and maintained operability.
3Ease of manufacture
If fasteners are inserted from accessible side crimping on inaccessible side, then ease of manufacture is improved, but ease of repair deteriorates
Solution Approach 1:
The patent inverts the traditional fastener approach by exposing the fastener heads on the upper accessible surface rather than hiding them. This allows both installation and removal/inspection to be performed from the same accessible side, improving ease of repair while maintaining ease of manufacture.
Solution Approach 2:
The patent makes the fastener system dynamic and reversible by allowing easy removal and reinstallation from the accessible upper surface. This enables maintenance personnel to remove, inspect, and replace fasteners without complex procedures, significantly improving ease of repair while keeping manufacturing simple.
4Strength
If traditional fastening systems are used in thin wings, then structural integrity is improved, but ease of operation deteriorates
Solution Approach 1:
The patent moves the fastener heads to the upper surface dimension, making them accessible from above rather than requiring access from the lower side or through panels. This spatial repositioning maintains structural integrity in thin wings while dramatically improving ease of operation for inspection and removal.
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 system effectively isolates fasteners electrically, provides easy access for maintenance, and reduces the weight and drag associated with traditional access panels, while ensuring the structural integrity and lightning protection of aerospace vehicle components.
Implementation Method 1
A dielectric nut retainer strip (34) having one or more fastener thru holes (36), an integrally formed nut retention pocket (35) adjacent to each of the one or more fastener thru holes (36)... effectively isolates fasteners electrically
Implementation Method 2
at least one fastener comprising a conductive coating... ensures the structural integrity and lightning protection of aerospace vehicle components
Data Source
AI summary
A fastening system for aerospace vehicles including a dielectric nut retainer strip formed of dielectric material and having at least one fastener thru hole and at least one cap receiver portion. Also included are an anti-rotation nut retainer portion integrally formed in the dielectric nut retainer adjacent to the at least one fastener thru hole, a cap configured to mate with the at least one cap receiver portion, a fastener covered in a conductive coating, and an anti-rotation nut configured to fit in the anti-rotation nut retainer portion and couple with the fastener.


