Pivotal Avoidance Panel for Aircraft Thrust Reverser Slats
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Solution Overview
Problem
Existing thrust reverser systems for aircraft nacelles face interference issues with movable slats due to surface defects and operating clearances, leading to aerodynamic and kinematic constraints, particularly when the avoidance panel is not compatible with the kinematics of the movable cowl.
Innovation Solution
A thrust reverser design with a pivotally mounted avoidance panel that is constrained to bear against the movable cowl using an energy storage device, allowing for relative mobility and reducing operating clearances through a kinematic connection, which compensates for deformations and wear, and features bearing areas on the periphery for reduced overlap and improved structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed avoidance panel is used to prevent interference with movable slats, then interference is eliminated, but surface defects and operating clearances appear between the panel and movable cowl
Solution Approach 1:
The avoidance panel is made movable relative to the fixed structure, allowing it to adapt its position dynamically. The panel can pivot or translate to maintain surface continuity with the movable cowl while still preventing interference with the wing slats, thereby eliminating the operating clearances and surface defects caused by rigid fixed panels.
Solution Approach 2:
The avoidance panel is divided into multiple segments or sections that can move independently relative to each other and the fixed structure. This segmentation allows each section to accommodate the kinematic movements of the movable cowl while maintaining overall surface continuity, resolving the contradiction between interference prevention and surface precision.
2Device complexity
If the avoidance panel is fixed to the fixed structure, then structural simplicity is maintained, but aerodynamic performance deteriorates due to operating clearances
Solution Approach 1:
The avoidance panel incorporates movable elements that can adjust their position to eliminate gaps and maintain aerodynamic continuity with the movable cowl. This dynamic adjustment eliminates operating clearances that would otherwise cause aerodynamic losses, while the movement mechanisms are designed to be relatively simple.
Solution Approach 2:
An intermediary mechanism or element is introduced between the fixed structure and the avoidance panel to enable relative movement. This intermediary allows the panel to adapt to the movable cowl's position, eliminating aerodynamic gaps while keeping the overall system relatively simple through the use of straightforward mechanical linkages or flexible connections.
3Loss of energy
If the avoidance panel is made movable to reduce operating clearances, then aerodynamic performance improves, but device complexity increases
Solution Approach 1:
The avoidance panel uses simple dynamic mechanisms such as pivots, sliders, or flexible hinges that allow the panel to move and maintain surface continuity with the movable cowl. These mechanisms are designed to be minimally complex while effectively eliminating operating clearances and improving aerodynamic performance.
Solution Approach 2:
The avoidance panel is designed to move automatically in response to the kinematic movements of the movable cowl, without requiring complex control systems or active actuation. The panel's movement is self-regulated through mechanical linkages or elastic elements that naturally accommodate the cowl's position, reducing device complexity while maintaining aerodynamic efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces or eliminates operating clearances, enhancing aerodynamic performance and kinematic compatibility, preventing interference with movable slats and maintaining thrust reversal efficiency.
Implementation Method 1
at least one energy storage device configured so that the avoidance panel is constrained to bear against the movable cowl
Data Source
AI summary
A thrust reverser for a nacelle of an aircraft engine includes a movable cowl movable between a closed position in which thrust is not reversed and an open position for uncovering cascades reversing that reverse the direction of the cold air flow diverted from the annular secondary air flow path. The movable cowl includes a radially outer portion disposed proximate a leading edge of an aircraft wing and at least one avoidance panel on the radially outer portion designed to inhibit interference with a movable slat of the leading edge of the aircraft wing. The avoidance panel is pivotally mounted with respect to a fixed structure of the thrust reverser. At least one energy storing device constrains the avoidance panel to bear against the movable cowl, at least when the thrust reverser is in the closed position.