Thrust Reverser Linkage Hiding for Drag Reduction

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Solution Overview

Problem

Conventional thrust reverser systems experience drag losses due to drag links positioned within the bypass air flow, degrading efficiency and requiring inefficient component designs.

Innovation Solution

The drag links are eliminated, and instead, pushrods and four-bar mechanisms are positioned inside a translating sleeve to actuate blocker doors, allowing for selective exposure or hiding of cascades during thrust reversal, minimizing drag and optimizing component placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drag links are used to attach blocker doors to the thrust reverser structure, then the blocker doors can be retained in position and deployed, but drag losses occur due to the drag links lying within the bypass air flow

Engineering Contradiction:

Improveblocker door positioningVSAvoiddrag losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The drag links are completely removed from the bypass air flow path. The blocker doors are repositioned to pivot on the translating sleeve itself, and the linkage mechanism is relocated inside the sleeve, extracting the harmful drag-generating components from the external airflow while maintaining the necessary door positioning and deployment functions.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of operation

If drag links are positioned within the bypass air flow to aid deployment, then deployment function is achieved, but efficiency is degraded

Engineering Contradiction:

Improvedeployment functionVSAvoidefficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The translating sleeve acts as an intermediary structure that houses the linkage mechanism internally. The sleeve mediates between the thrust reverser actuation and the blocker door deployment, allowing the linkage to function without exposing drag-generating components to the bypass air flow, thus maintaining deployment capability while improving efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If linkage components are positioned outside the sleeve, then deployment is aided, but component packaging becomes less compact

Engineering Contradiction:

Improvedeployment assistanceVSAvoidcomponent packaging

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The linkage mechanism is nested inside the translating sleeve, with the drag links and other components positioned within the sleeve's internal volume. This nested arrangement consolidates the deployment mechanism within the existing sleeve structure, achieving more compact packaging while maintaining the deployment function through the sleeve's own motion.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentEP3018327B1Thrust reverser with hidden linkage blocker doors

Publication Date: 2018.04.25 ROHR INC

Figure 1A
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AI summary

Aspects are directed to a system that includes an outer structure of a thrust reverser, a blocker door (208), and a plurality of four-bar mechanisms arranged in series with one another that couple the outer structure and the blocker door (208). Aspects are directed to a system for a thrust reverser of an aircraft that includes a blocker door (208), a kinematic mechanism configured to actuate the blocker door (208), and a pressure shelf (240), where the blocker door (208) is configured to reside below the pressure shelf (240) in proximity to a duct of the thrust reverser, and where at least a portion of the kinematic mechanism is configured to reside above the pressure shelf (240).