Aircraft Canopy Flange with Load-Distributing Member
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Solution Overview
Problem
Existing aircraft canopy fastening techniques face challenges such as mechanical stress on window panes, difficulty in disassembly due to countersunk screws, and inadequate air and moisture sealing, leading to increased costs and aircraft grounding times.
Innovation Solution
A laminated aircraft canopy with a flange and window pane assembly that uses hexagon-head screws and a load-transferring and distributing member to simplify assembly and disassembly, control prestressing forces, and provide dry sealing without additional curing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If countersunk screws are used to fasten the flange to the frame, then the sealing between flange and frame is improved, but the machining precision requirements and assembly complexity increase significantly
Solution Approach 1:
A sealing ring is introduced as an intermediary element between the flange and the frame. The sealing ring is installed in a groove on the flange and protrudes to contact the frame, providing the sealing function without requiring the flange itself to have high machining precision. This mediator absorbs the sealing requirement, allowing the flange and frame to be manufactured with standard tolerances.
2Strength
If countersunk screws are used for fastening, then the structural integrity is improved, but the ease of disassembly deteriorates due to difficulty in accessing and removing the screws
Solution Approach 1:
A removal tool is introduced as an intermediary device that interfaces with the hexagonal head of the fastening screw. The tool is inserted through the frame's opening, engages with the screw head, and transmits torque to loosen and remove the screw. This mediator enables easy access and removal of the screw without compromising the structural integrity provided by the countersunk screw design.
3Ease of operation
If hexagon-head screws are used instead of countersunk screws, then the ease of operation for tightening and loosening is improved, but the sealing between screw and flange deteriorates
Solution Approach 1:
The fastening system is segmented into distinct functional elements: the hexagon-head screw provides the fastening and ease of operation, while a separate sealing ring provides the air and moisture sealing. The sealing ring is positioned in a groove on the flange and protrudes to contact the frame, creating a dedicated sealing interface that is independent of the screw head design. This segmentation allows each component to optimize its specific function without compromise.
Data Source
AI summary
An aircraft canopy includes a window pane, a frame from a primary structure of the aircraft, and a flange fastened to the frame with fastening screw, characterized in that: the flange is secured to the peripheral edge of the window pane by engaging of at least one plate of the flange between plies of the window pane, so that flange and window pane form an all in one-piece assembly, at each fastening screw, a load-transferring and distributing member is arranged between an outer surface of the flange and the fasting screw, a cavity being provided in the flange for receiving the load-transferring and distributing member, the member having a recess for receiving the screw head.