Wing Spar Nut Plate Assembly for Exterior-Only Fastening
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Solution Overview
Problem
The assembly of aircraft wing panels to wing spars is time-consuming due to limited accessibility and the need for installers to access the interior of the wing assembly, especially in thinner designs where space is restricted.
Innovation Solution
A nut plate assembly is introduced, featuring a base plate with reinforcement lips forming seal grooves, channel fittings, and nut caps that hold nuts in position within the wing assembly, allowing fasteners to be secured from the exterior without interior access, and providing sealing and spark arrest features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the wing assembly is designed to be thinner, then the weight and drag are reduced, but the accessibility for installers is limited and assembly time increases
Solution Approach 1:
The nut plate assembly is pre-positioned and secured to the wing spar before the wing panel is installed. This preliminary action allows the nuts to be held in place and ready for fastener installation, eliminating the need for installers to access the interior of the thin wing assembly during the fastening process, thus maintaining reduced assembly time despite the thinner design
2Ease of manufacture
If the installer needs to access the interior of the wing assembly to position and hold the nut, then the fastening can be completed, but the assembly process becomes time-consuming
Solution Approach 1:
The nut plate assembly is designed to self-retain the nuts through its structure, including the base plate secured to the wing spar and the channel fittings that hold the nuts in position. This self-service mechanism eliminates the need for installer intervention to position and hold nuts during fastening, significantly reducing assembly time while ensuring proper fastening completion
3Strength
If the interior space of the wing assembly is not easily accessible, then the structural integrity is maintained, but the assembly process becomes difficult
Solution Approach 1:
The nut plate assembly is pre-installed and secured to the wing spar before the wing panel is attached. This preliminary positioning ensures that the nuts are held in the correct locations and that the assembly process can proceed from the exterior side only, making the assembly process easy even though the interior space remains inaccessible and maintains structural integrity
Data Source
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AI summary
A nut plate assembly includes a base plate having base plate openings. The nut plate assembly includes channel fittings coupled to the bottom of the base plate each having a main body with a top facing the bottom of the base plate. Each channel fitting has a nut cap channel at the bottom of the main body aligned with the opening in the main body. The nut plate assembly includes nut caps received in the nut cap channels coupled to the channel fittings and positioned below the bottom of the main body. Each nut cap has a pocket holding a nut to receive a fastener used to secure the base plate to the mounting structure from an exterior surface of the mounting structure through the base plate and the main body of the channel fitting.