Guided Fan Cowl Hinge Assembly for Easier Nacelle Maintenance
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Solution Overview
Problem
The design of fan cowl hinge systems for gas turbine engines, particularly those fuselage-mounted, faces challenges in accessibility and maintenance due to the length and configuration of the upper and lower fan cowls, making it difficult to access and disassemble components intermediate the entrance and exit sections of the nacelle.
Innovation Solution
A fan cowl assembly with a hinge system that includes a first pin member connected to the fan cowl and an inboard fan cowl section, a second intermediate hinge with a pin member extending in the longitudinal direction, and locking members to prevent translation, allowing for assembly and disassembly of the fan cowl components, facilitating maintenance and access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the fan cowl sections are made long in axial direction to accommodate fuselage-mounted engine requirements, then the engine can be properly sized and positioned, but accessibility to hinge system components intermediate to entrance and exit sections becomes difficult
Solution Approach 1:
The hinge system is divided into multiple independent hinge assemblies (first hinge assembly and second hinge assembly) positioned at different locations along the fan cowl. Each hinge assembly can be accessed and serviced independently, allowing maintenance personnel to work on specific sections without needing to access the entire length of the fan cowl, thereby resolving the accessibility issue despite the long axial dimension.
2Length of moving object
If the fan cowl sections are made long in axial direction, then the engine can be properly sized, but disassembly and maintenance of hinge system components becomes difficult
Solution Approach 1:
The fan cowl is segmented into upper and lower sections that can be independently removed. The hinge assemblies are positioned such that when the fan cowl sections are removed, the hinge components become accessible from the exterior, allowing maintenance personnel to service the hinge system without needing to disassemble the entire engine or access components from within the long axial space.
Solution Approach 2:
The hinge assemblies act as intermediary connection points between the upper and lower fan cowl sections. By designing these hinge assemblies with external access features and positioning them at strategic locations, the system allows maintenance personnel to service the connection mechanisms without needing to penetrate or access the interior of the long fan cowl sections.
3Device complexity
If traditional hinge systems are used in long fan cowls, then the structure can be simple, but accessibility and maintenance of intermediate components becomes difficult
Solution Approach 1:
Rather than using a single complex hinge system spanning the entire length of the fan cowl, the invention segments the hinge system into multiple simpler, identical hinge assemblies. Each assembly is a straightforward mechanical connection that can be independently accessed and serviced, maintaining structural simplicity while dramatically improving accessibility to individual components.
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A hinge assembly for assembling a fan cowl (304) to an inboard fan cowl section (308) is disclosed. In various embodiments, the hinge assembly includes a forward hinge (320); an aft hinge (322) spaced a distance in a longitudinal direction from the forward hinge; and a first intermediate hinge (324) disposed between the forward hinge and the aft hinge, the first intermediate hinge including a first aperture (485) and a first pin member (490) extending in the longitudinal direction, the first aperture configured to receive the first pin member when the fan cowl is translated in the longitudinal direction with respect to the inboard fan cowl section.