Folding-Linkage Thrust Reverser for Low-Drag Blocker Door Deployment
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Solution Overview
Problem
Traditional thrust reversers for aircraft propulsion systems increase bypass duct drag when not in use, reducing engine efficiency during cruise operations due to the presence of drag links that extend across the bypass duct.
Innovation Solution
The use of a translating sleeve with a folding linkage and a roller mechanism that allows blocker doors to pivot inward as the translating structure moves from a stowed to a deployed position, eliminating the need for drag links and reducing drag when the thrust reverser is not in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drag links are used to pivot blocker doors in traditional thrust reversers, then blocker door deployment is enabled, but bypass duct drag increases and engine efficiency decreases during cruise
Solution Approach 1:
The patent removes the drag links from the thrust reverser system entirely. Instead of using drag links to pivot the blocker doors, the invention uses a different mechanism (cam followers and cam surfaces) that allows the blocker doors to pivot without requiring links that extend across the bypass duct during cruise, thereby eliminating the drag penalty while maintaining deployment capability.
Solution Approach 2:
The patent replaces the traditional drag link mechanical system with a cam-follower mechanism. The blocker doors are pivoted using cam surfaces and cam followers that engage during deployment, eliminating the need for drag links that would otherwise extend across the bypass duct and create drag during normal engine operation.
2Ease of operation
If drag links extend across the bypass duct in stowed position, then blocker door pivoting is facilitated, but bypass duct drag increases during normal operation
Solution Approach 1:
The patent extracts the drag-inducing drag links from the system and replaces them with a cam-follower mechanism that does not require components to extend across the bypass duct during cruise, thereby eliminating the harmful drag effect while preserving the blocker door pivoting function.
Solution Approach 2:
The patent employs a dynamic cam-follower mechanism where the cam surfaces and followers engage only when needed for blocker door deployment. During normal cruise operation, the mechanism remains retracted or disengaged, allowing the bypass duct to operate without obstruction, thus dynamically adapting to operational requirements.
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 minimizes drag and enhances engine efficiency by allowing the thrust reverser components to retract from the bypass duct when not in use, thereby reducing energy consumption during normal flight operations.
Implementation Method 1
a roller (88) rotatably connected to the folding linkage
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An assembly is provided for an aircraft propulsion system. This assembly includes a fixed structure (50), a translating structure (52), a blocker door (46) and a folding linkage (70). The translating structure (52) is configured to move between a stowed position and a deployed position. The blocker door (46) is pivotally attached to the translating structure (52) at a first pivot joint (78). The folding linkage (70) links the blocker door (46) to the fixed structure (50). The folding linkage (70) includes a member (86) pivotally attached to the blocker door (46) at a second pivot joint (106) that is radially outboard of a skin (107) of the blocker door (46) when the translating structure (52) is in the stowed position. The second pivot joint (106) is radially outboard of the first pivot joint (78) when the translating structure (52) is in the stowed position.