Folding Blocker Door Mechanism for Aircraft Thrust Reversers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft thrust reverser systems experience increased drag due to the presence of drag links and gaps between blocker doors and the translating sleeve, which create flow disturbances in the bypass duct during deployment and stowage.
Innovation Solution
A folding blocker door mechanism with a rigid linkage system, including a four-bar link system, where the outer and inner panels pivotally attached to each other and the translating structure, and a biasing device to facilitate deployment without extending across the bypass duct, reducing drag and flow disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a drag link extends completely radially across the bypass duct to connect the blocker door to the inner fixed structure, then the blocker door can be moved from stowed to deployed position, but drag within the bypass duct increases
Solution Approach 1:
The blocker door is divided into multiple segments (first blocker door portion and second blocker door portion) that can move independently. The first portion is pivotally connected to the translating sleeve while the second portion is pivotally connected to the drag link, allowing the drag link to be positioned away from the bypass duct flow path while still enabling blocker door deployment.
Solution Approach 2:
The drag link is repositioned from extending radially across the bypass duct to being positioned in a different spatial arrangement where it connects to the blocker door but does not extend across the bypass duct. This dimensional repositioning eliminates the drag caused by the drag link while maintaining its function of moving the blocker door.
2Ease of operation
If gaps exist between the blocker doors and the translating sleeve when stowed, then the blocker doors can be deployed, but flow disturbances within the bypass duct increase
Solution Approach 1:
The blocker door is designed with dynamic positioning capability where the first blocker door portion can pivot relative to the translating sleeve. During stowage, the blocker door portions are positioned to minimize gaps and flow disturbances, while during deployment, they pivot to their functional positions. This dynamic adjustment optimizes both stowage compactness and flow characteristics.
3Reliability
If the blocker door projects radially inward into the bypass flowpath when deployed, then reverse thrust coverage is improved, but drag within the bypass duct increases when stowed
Solution Approach 1:
The blocker door is segmented into multiple portions that can be independently positioned. The first portion connects to the translating sleeve and the second portion connects to the drag link, allowing the blocker door to project radially inward into the bypass flowpath when deployed for reverse thrust coverage, while being repositioned to minimize drag when stowed.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An assembly is provided for an aircraft propulsion system (10). This assembly includes a fixed structure (48), a translating structure (50), a blocker door (46) and a rigid linkage (74). The translating structure (50) is configured to translate relative to the fixed structure (48). The blocker door (46) extends between a blocker door first end (82) and a blocker door second end (86). The translating structure (50) is pivotally attached to the blocker door (46) at the blocker door first end (82). The rigid linkage (74) includes a first pivot attachment, a second pivot attachment and a third pivot attachment. The first pivot attachment is coupled to the fixed structure (48). The second pivot attachment is coupled to the translating structure (50). The third pivot attachment is coupled to the blocker door (46) at the blocker door second end (86).