Fan Cowl Articulation With Offset Cylinders for Interaction Control
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Solution Overview
Problem
Interactions between fan cowls in aircraft propulsion systems cause parasitic drag, and existing solutions like spacing them apart do not adequately address this issue.
Innovation Solution
An articulation system with a central and lateral cylinder arrangement, featuring locking and stopping mechanisms, allows fan cowls to move laterally and rotate independently, preventing interactions and reducing drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fan cowls are spaced further apart to prevent interactions, then interactions between cowls are reduced, but parasitic drag increases due to larger gaps
Solution Approach 1:
The fan cowl is designed with dynamic movement capability through an articulation system comprising a central cylinder and lateral cylinder. The cowl can move laterally via the lateral cylinder's rotation and rotate via the central cylinder's rotation, allowing it to adapt its position dynamically. This enables the cowl to maintain optimal spacing and orientation relative to adjacent cowls during operation, preventing interactions without requiring permanent large gaps that would increase parasitic drag.
2Object-generated harmful factors
If fan cowls are positioned closer together to reduce parasitic drag, then aerodynamic efficiency improves, but interactions between cowls occur during opening/closing operations
Solution Approach 1:
The articulation system allows the fan cowl to move dynamically between closed and open positions while maintaining controlled spacing. The locking mechanism ensures that when the cowl is in the closed position, it is securely held to prevent unwanted movements that could cause interactions with adjacent cowls, while still allowing the cowl to be positioned closer together to minimize parasitic drag.
Solution Approach 2:
The locking mechanism acts as an intermediary between the cowl and the chassis, providing controlled restraint. It allows the cowl to be held firmly in the closed position to prevent interactions, while the articulation system provides the intermediary movement capability to open and close the cowl without causing harmful interactions with adjacent structures.
3Device complexity
If traditional hinged fan cowls are used, then the structure is simple, but interactions occur between adjacent cowls during operation
Solution Approach 1:
The articulation system is segmented into distinct functional components: a central cylinder for rotation, a lateral cylinder for lateral movement, and a locking mechanism for position control. This segmentation allows each component to perform its specific function independently, providing precise control over the cowl's movement and positioning to prevent interactions with adjacent cowls while maintaining manageable structural complexity.
Solution Approach 2:
The articulation system transforms the static hinged structure into a dynamic system with multiple degrees of freedom. The central and lateral cylinders enable the cowl to move in multiple directions (rotation and lateral displacement), providing the flexibility needed to prevent interactions with adjacent cowls while maintaining a relatively simple overall structure.
Data Source
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AI summary
The invention relates to a propulsion system comprising a chassis (402), a fan cowl (208), an articulation system (300) fixed between the chassis (402) and the fan cowl (208) and comprising a shaft (302) with two offset cylinders, where a central cylinder is mounted for rotation on the chassis (402) and a lateral cylinder is mounted for rotation on the fan cowl (208), locking means (306) limiting the rotation of the central cylinder relative to the chassis (402) between a closed position and an intermediate position, and stopping means (308) allowing the rotation of the fan cowl (208) between the intermediate position and the open position and preventing the rotation of the fan cowl (208) beyond the intermediate position. With such an arrangement, the fan cowl moves laterally from the beginning of its opening, which limits the risk of interactions.