Thrust Reverser Blocker Door Lock for Reduced Flowpath Drag
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Solution Overview
Problem
Existing thrust reversers in aircraft propulsion systems suffer from increased bypass flowpath drag due to drag links extending across the flowpath when not in use, reducing engine efficiency during normal operation.
Innovation Solution
A thrust reverser assembly with a blocker door that is pivotally coupled to a translating structure, featuring an actuation linkage and a door lock that delays the pivoting of the blocker door into the flowpath during translation, using a latch crank or catch and latch mechanism to lock the actuation linkage, eliminating the need for drag links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If drag links are used to pivot blocker doors, then blocker door deployment is achieved, but bypass flowpath drag increases and engine efficiency decreases
Solution Approach 1:
The patent removes the drag link from the system entirely and replaces it with an actuation linkage that connects the blocker door directly to the translating structure. This extraction of the harmful drag link element eliminates the source of flowpath drag while maintaining the necessary blocker door deployment function through the new linkage mechanism.
Solution Approach 2:
Instead of using a drag link that extends across the flowpath to pivot the door, the invention inverts the approach by connecting the blocker door to the translating structure through an actuation linkage that moves with the translating structure, keeping components out of the flowpath during normal operation.
2Ease of operation
If actuation linkage is connected to fixed structure, then blocker door pivoting is achieved, but linkage extends across flowpath increasing drag
Solution Approach 1:
The actuation linkage is made dynamic by connecting it to the translating structure instead of a fixed structure. As the translating structure moves during thrust reverser deployment, the actuation linkage moves with it, keeping the linkage out of the bypass flowpath during normal engine operation while still enabling blocker door actuation when needed.
Solution Approach 2:
The translating structure serves as an intermediary between the fixed structure and the actuation linkage. This intermediary allows the linkage to be actuated without extending across the flowpath, as the translating structure absorbs the movement and positioning function, keeping the linkage components clear of the bypass flowpath.
3Loss of energy
If door lock delays blocker door deployment, then drag is reduced during translation, but deployment timing control is required
Solution Approach 1:
The door lock mechanism is self-actuating through the interaction between the latch and catch. As the translating structure moves during deployment, the relative motion automatically engages or disengages the latch and catch, providing self-service timing control without requiring additional actuators or complex control systems. The mechanism uses the motion itself to control the timing.
Solution Approach 2:
The door lock mechanism is designed to delay blocker door deployment until the translating structure has moved to the appropriate position. The latch and catch are positioned and configured to engage during translation, preliminarily holding the door in place until the optimal timing is reached, at which point the door is automatically released.
Data Source
AI summary
An assembly is provided for an aircraft propulsion system. This assembly includes a fixed structure, a translating structure and a thrust reverser. The translating structure is configured to translate between a stowed position and a deployed position. The thrust reverser includes a blocker door, an actuation linkage and a door lock. The blocker door is pivotally coupled to the translating structure. The actuation linkage operatively couples the blocker door to the fixed structure such that translation of the translating structure to the deployed position actuates pivoting of the blocker door into a flowpath. The door lock is configured to lock the actuation linkage to the translating structure such that the pivoting of the blocker door into the flowpath is delayed as the translating structure translates from the stowed position towards the deployed position.