Thrust Reverser Sleeve Translation and Blocker Door Nesting
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Solution Overview
Problem
Conventional thrust reverser systems in aircraft experience inefficiencies and noise reduction challenges due to the stowed position of blocker doors interfacing with the bypass duct, leading to losses and limited acoustic treatment areas, and fixed cascades restricting sleeve length.
Innovation Solution
A thrust reverser system where the sleeve and cascades translate via a common actuator, with a blocker door contained within the sleeve in the stowed state, using a track and link mechanism with trapping devices and a hinge for controlled deployment, allowing optimized reverse thrust performance and increased acoustic treatment area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the blocker door is in the stowed position interfacing with the bypass duct, then the thrust reverser is compact during cruise, but this creates steps and gaps that cause flow losses and reduce acoustic treatment area
Solution Approach 1:
The blocker door is nested within the sleeve structure during stowed configuration, eliminating the need for it to interface with the bypass duct. This nesting approach removes the harmful steps and gaps while maintaining system compactness, as the blocker door becomes part of the internal sleeve assembly rather than an external component.
Solution Approach 2:
The blocker door is extracted from the bypass duct interface and repositioned within the sleeve. This extraction eliminates the source of flow losses (steps and gaps at the bypass duct interface) while the blocker door retains its function within the new location, improving acoustic treatment area.
2Length of moving object
If the cascades are fixed and do not translate, then the structure is simpler, but this restricts the sleeve length that can be used
Solution Approach 1:
The cascade translation mechanism is merged with the sleeve actuation system through a common actuator. This allows both components to move together as a coordinated unit, enabling longer sleeve designs without requiring separate, complex actuation systems for the cascades.
Solution Approach 2:
The common actuator serves multiple functions: it actuates the sleeve and simultaneously drives the cascade translation. This multi-functionality reduces overall system complexity while enabling increased sleeve length, as one actuator performs what would traditionally require multiple independent mechanisms.
3Area of stationary object
If the blocker door is contained within the sleeve cavity when stowed, then acoustic treatment area is increased, but the deployment control mechanism becomes more complex
Solution Approach 1:
The blocker door transitions from a static nested position to a dynamic deployed position through the track and link mechanism. This dynamic capability allows the blocker door to move between containing (acoustic treatment) and blocking (reverse thrust) positions, with trapping devices providing automated position control that manages the complexity of the movement.
Solution Approach 2:
The trapping devices are pre-positioned within the track to automatically capture and hold the blocker door at specific positions. This preliminary positioning of the trapping mechanisms simplifies the overall control system by providing passive position holding rather than requiring active control throughout the entire deployment range.
4Device complexity
If the sleeve and cascades translate via a common actuator, then system complexity is reduced, but precise independent control of each component is lost
Solution Approach 1:
The common actuator employs an asymmetric mechanical linkage system where different portions of the actuator's range of motion produce different effects: initial movement translates the sleeve, while subsequent movement translates the cascades. This asymmetric design allows one actuator to provide effectively independent control of both components through its sequential action.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
System (202) of a thrust reverser of an aircraft, comprising: a set of cascades (270) incorporating a track (280;380), the track (280;380) including a first track end (380b) and a second track end (380c), a blocker door (266), and a link (274;374) including a first link end (274a) coupled to the track (280;380) and a second link end (274b) coupled to the blocker door (266), where the cascades (270) are configured to translate between a stowed position and a deployed position to cause the first link end (274a) to traverse the track (280;380).