Aircraft Engine Pylon Mobile Cowl Sliding Mechanism
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Solution Overview
Problem
Conventional aircraft engine pylons with fixed cowls are heavy, require rigid structures for fastening, and result in air flow disruptions and acoustic issues due to manufacturing tolerances and the need for removable hatches, which complicate maintenance and access.
Innovation Solution
A mobile cowl system for the engine pylon with a sliding rear cowl that can be moved between advanced and retracted positions, eliminating the need for separate access hatches and simplifying the structure, while maintaining aerodynamic continuity and reducing acoustic phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If removable hatches are provided on fixed cowls to access the engine pylon interior, then maintenance access is enabled, but the structural complexity increases and aerodynamic performance deteriorates due to gaps and discontinuities
Solution Approach 1:
The patent transforms the static cowl structure into a dynamic one by introducing a mobile cowl that can slide between a closed position (aerodynamically smooth) and an open position (providing maintenance access). The displacement system with rails and grooves enables this dynamic transformation, eliminating the need for removable hatches and their associated structural complexity.
Solution Approach 2:
The cowl is divided into a fixed front set and a mobile rear cowl that can independently move. This segmentation allows the front portion to maintain aerodynamic continuity while the rear portion provides access when needed, resolving the contradiction between maintaining smooth airflow and enabling maintenance access.
2Object-affected harmful factors
If multiple fixed cowls are juxtaposed to cover the engine pylon, then aerodynamic coverage is improved, but manufacturing tolerances create gaps and discontinuities that disrupt air flow and generate acoustic phenomena
Solution Approach 1:
The mobile rear cowl merges with the front set of cowls to form a continuous aerodynamic surface when in the closed position. This merging eliminates the gaps and discontinuities that would otherwise exist between separate fixed cowls, reducing air flow disruption and acoustic phenomena while maintaining the benefit of comprehensive coverage.
3Strength
If rigid structures are used to fasten fixed cowls to the engine pylon, then structural strength is ensured, but the overall weight of the system increases
Solution Approach 1:
The patent replaces the need for heavy rigid fastening structures with a dynamic sliding mechanism using rails and grooves. The mobile cowl is guided and restrained by these simpler structural elements, which require less material and weight compared to rigid fastening systems, while still ensuring structural integrity during operation.
4Ease of operation
If removable hatches with threaded fasteners or rivets are used, then maintenance access is enabled, but local structural reinforcing elements are required which increase device complexity
Solution Approach 1:
The mobile cowl replaces removable hatches entirely by providing a large sliding opening. This dynamic access method eliminates the need for multiple small hatches with their associated threaded fasteners, rivets, and local reinforcing elements, significantly reducing structural complexity while maintaining easy maintenance access.
Data Source
AI summary
An engine pylon has a primary structure fastened between an engine and an aircraft wing and a cowling system having a front set of fixed cowls, a rear cowl, a displacement system having a first structure as one with the rear cowl and having a first slide mechanism, and a second structure fastened to a fixed structure of the wing and having second slide mechanism. The slide mechanisms cooperate so as to realize a sliding connection and to move the rear cowl in translation from an advanced position to a retracted position. An immobilizing system locks the rear cowl in the advanced position.