Slat-Thrust Reverser Clearance Design
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Solution Overview
Problem
The challenge is to position a high bypass ratio gas turbine engine propulsion system close to the aircraft wing without causing unintentional contact, which is essential for optimizing design while avoiding clashes and the need for taller, heavier landing gear.
Innovation Solution
A thrust reverser design featuring a translating sleeve with a slat cutout and a slat clearance door that moves to expose the cutout during deployment, creating a continuous aerodynamic surface and preventing contact with the wing slat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the nacelle is positioned close to the wing to optimize design, then the landing gear can be shorter and lighter, but the thrust reverser may contact the wing slat during operation
Solution Approach 1:
The slat clearance door is made movable rather than fixed, allowing it to dynamically adjust its position based on the thrust reverser's operational state. The door moves from a retracted position during thrust reverser operation to an extended position during normal flight, automatically maintaining safe clearance without requiring increased spacing that would necessitate taller landing gear.
Solution Approach 2:
The slat clearance door is positioned in advance to prevent potential contact between the thrust reverser and wing slat. By extending the door before thrust reverser deployment and retracting it only when needed, the design proactively eliminates clash risks while maintaining close nacelle-to-wing spacing, enabling shorter landing gear without compromising safety.
2Reliability
If the slat clearance door is extended to prevent contact, then clearance is maintained, but aerodynamic smoothness is disrupted
Solution Approach 1:
The slat clearance door transitions between extended and retracted positions based on operational requirements. During normal flight, the door is retracted to maintain a smooth aerodynamic surface. During thrust reverser operation, the door extends automatically to provide necessary clearance, minimizing aerodynamic disruption only when required.
Solution Approach 2:
The door design allows different portions of the nacelle exterior to have different functions at different times. The slat clearance door area serves as a protective barrier when extended, while the rest of the nacelle maintains continuous aerodynamic surfaces. This localized functional differentiation resolves the conflict between clearance requirements and overall aerodynamic smoothness.
Data Source
AI summary
A nacelle is provided comprising, a thrust reverser comprising a translating sleeve configured to translate between a stowed position and a deployed position, the translating sleeve comprising a slat cutout for clearance, and a slat door disposed at least partially in the slat cutout in response to the thrust reverser being in the stowed position, wherein the slat door is configured to move in response to the thrust reverser being in the deployed position to expose a portion of the slat cutout to accept a portion of a deployed forward wing slat.