Thrust Reverser Blocker Door Fairing Drag Reduction
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Solution Overview
Problem
Existing thrust reversers for aircraft propulsion systems suffer from increased bypass flowpath drag due to the extension of drag links across the flowpath, even when the thrust reverser is not in use, which reduces engine efficiency during typical aircraft operation.
Innovation Solution
The proposed assembly includes a translating structure and a thrust reverser with a blocker door, an actuation linkage, and a fairing. The blocker door is pivotally coupled to the translating structure, and the actuation linkage is disposed in a channel within the blocker door. The fairing projects into the flowpath and covers the channel when the translating structure is in the stowed position, minimizing drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drag links extend across the bypass flowpath to facilitate blocker door pivoting, then the thrust reverser can be deployed effectively, but bypass flowpath drag increases and engine efficiency decreases during normal operation
Solution Approach 1:
The drag link is extracted from the bypass flowpath by routing it through a dedicated drag link tunnel. This removes the harmful element (drag link) from the harmful environment (bypass flowpath) during normal operation, eliminating the drag penalty while preserving the drag link's essential function for thrust reverser deployment.
Solution Approach 2:
A drag link tunnel is introduced as an intermediary structure to accommodate the drag link. This tunnel acts as a mediator that allows the drag link to exist without interfering with the bypass flowpath, effectively decoupling the mechanical function from the aerodynamic penalty.
2Reliability
If actuation linkage is disposed in a channel within the blocker door, then the thrust reverser mechanism functions properly, but airflow disruption occurs and drag increases during normal operation
Solution Approach 1:
The actuation linkage is extracted from the blocker door channel and relocated to the drag link tunnel. This removes the source of airflow disruption (actuation linkage in channel) from the bypass flowpath, eliminating drag while maintaining the linkage's essential role in actuating the thrust reverser mechanism.
Solution Approach 2:
The drag link tunnel serves as an intermediary space that accommodates the actuation linkage during normal operation. This allows the linkage to be positioned away from the bypass flowpath, preventing airflow disruption while still enabling proper mechanical actuation when needed.
3Object-affected harmful factors
If fairing projects into the flowpath to cover the channel, then aerodynamic coverage is improved, but the structure becomes more complex
Solution Approach 1:
The fairing is merged with the drag link tunnel structure, combining two functions into a single integrated component. The tunnel both houses the actuation linkage and provides aerodynamic fairing, eliminating the need for a separate fairing structure and reducing overall system complexity.
Solution Approach 2:
The drag link tunnel is designed to serve multiple functions: it accommodates the drag link, houses the actuation linkage, and provides aerodynamic fairing. This multi-functionality reduces the number of separate components needed, simplifying the overall structure while maintaining aerodynamic performance.
Data Source
AI summary
An assembly for an aircraft propulsion system includes a translating structure and a thrust reverser. The thrust reverser includes a blocker door, an actuation linkage and a fairing. The blocker door is pivotally coupled to the translating structure. The blocker door includes a door surface and a channel projecting into the blocker door from the door surface. The door surface forms an outer peripheral boundary of a flowpath when the translating structure is stowed. The door surface projects into the flowpath when the translating structure is deployed. The actuation linkage is pivotally coupled to the blocker door. The actuation linkage is disposed in the channel when the translating structure stowed. The fairing projects away from the door surface into the flowpath. The fairing forms an aerodynamic cover over the channel when the translating structure is stowed.