Aircraft Propulsion System Movable Outer Cowl Maintenance Access
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Solution Overview
Problem
Conventional aircraft propulsion systems require lengthy and arduous maintenance operations due to limited access, necessitating the dismantling of heavy outer and internal structures to access the engine, which is inefficient and labor-intensive.
Innovation Solution
A propulsion system featuring a movable and articulated outer cowl that can translate rearward, allowing the outer and internal structures to be moved away from the engine, enabling easier access without disassembly, utilizing a mechanical transmission system and locking mechanisms to facilitate this movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer cowl is made fixed and heavy to ensure structural strength, then the structural strength is improved, but the maintenance operation becomes lengthy and arduous requiring dismantling of heavy parts
Solution Approach 1:
The outer cowl is transformed from a fixed structure to a movable one through the introduction of a translation system with sliding links and a rotating beam. The cowl can translate rearward along guide rails and rotate about a vertical axis, enabling dynamic reconfiguration for maintenance access while maintaining structural integrity through controlled mechanical connections.
Solution Approach 2:
The outer cowl is divided into multiple independent parts: the cowl itself, the translation system with sliding links, the rotating beam, and the locking mechanism. This segmentation allows the cowl to be moved and positioned independently without requiring dismantling of the entire propulsion system, improving maintenance efficiency while preserving structural strength through modular connections.
2Productivity
If the outer cowl is made movable to improve maintenance access, then the maintenance efficiency is improved, but the device complexity increases due to additional translation and locking mechanisms
Solution Approach 1:
The translation system combines multiple functions into an integrated mechanism: the sliding links provide both guidance and support for the cowl's rearward movement, while the rotating beam simultaneously enables angular positioning and acts as a lever for the locking mechanism. This merging reduces the number of separate components compared to using independent systems for each function.
Solution Approach 2:
The sliding links act as intermediary elements between the fixed internal structure and the movable outer cowl, transferring loads and enabling controlled movement. The locking mechanism serves as an intermediary that mediates between the cowl's movable state and its fixed operational position, simplifying the control architecture by providing a single engagement point.
3Object-affected harmful factors
If the outer cowl remains in forward position to maintain aerodynamic continuity, then the aerodynamic performance is improved, but the engine access becomes limited requiring cowl removal
Solution Approach 1:
The outer cowl transitions from a static forward position optimized for aerodynamics to a dynamic rearward position that provides engine access. The cowl can be translated rearward along the longitudinal axis and rotated about a vertical axis, creating variable configurations that balance aerodynamic performance with maintenance accessibility requirements.
Solution Approach 2:
The cowl movement is extended beyond simple linear translation by adding rotation about a vertical axis. This dimensional addition allows the cowl to clear the engine area more effectively when moved to the rearward position, providing comprehensive access to engine components while maintaining aerodynamic continuity in the forward position.
Data Source
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AI summary
The invention relates to a propulsion system (100) comprising a turbofan engine (150) and a mast (152), wherein the turbofan engine (150) comprises an engine (156), two inner cowlings (159), and two outer cowlings (164), first locking means for locking the inner cowlings (159) to the engine (156), cascades (256) which are attached to the outer cowling (164) by means of strapping means (258), wherein the outer cowlings (164) are movable in translation relative to the engine (156), wherein each outer cowling (164) slides parallel to a direction of translation on an inner cowling (159) by means of an upper slide joint (170) and a lower slide joint (172), and wherein each outer cowling (164) is mounted to slide parallel to the direction of translation on the mast (152) by means of a link top slide (174).Such a propulsion system thus makes it possible during maintenance operations to move the outer hood and the fixed internal structure towards the rear and therefore away from the front hoods in order to free the engine.