Blocker Door Folding Linkage for Low-Drag Thrust Reversers

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Solution Overview

Problem

Existing thrust reversers in aircraft propulsion systems experience increased bypass flowpath drag due to drag links extending across the bypass flowpath when not in use, reducing engine efficiency during typical operation.

Innovation Solution

The introduction of a structure link and door link assembly, including a Y-shaped link, which is nested within the blocker door in the stowed position, minimizing exposure to the bypass flowpath and reducing drag by converging laterally towards a structure link mount, and a door link that projects through the blocker door during deployment, allowing for simultaneous movement with the translating sleeve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If drag links are used to pivot blocker doors, then blocker door deployment is facilitated, but bypass flowpath drag increases and engine efficiency decreases

Engineering Contradiction:

Improveblocker door deploymentVSAvoidengine efficiency

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The actuation linkage is nested within the blocker door assembly when not in use. The structure link and door link are positioned inside the blocker door or along its leading edge, minimizing exposure to the bypass flowpath. This nesting approach eliminates the need for drag links extending across the flowpath while maintaining the ability to pivot the blocker door during deployment.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Device complexity

If drag links extend across the bypass flowpath, then blocker door actuation is simplified, but bypass flowpath drag increases

Engineering Contradiction:

Improveactuation mechanismVSAvoidbypass flowpath drag

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The actuation linkage transitions from a linear extension across the flowpath to a compact, multi-dimensional arrangement. The structure link and door link form a folded configuration that fits within the three-dimensional space of the blocker door assembly, eliminating the need for components to extend across the bypass flowpath while maintaining actuation functionality.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If actuation linkage is exposed to bypass flowpath, then blocker door can be actuated, but drag increases and performance decreases

Engineering Contradiction:

Improveblocker door actuationVSAvoidengine performance

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS12467419B2Thrust reverser with blocker door folding linkage

Publication Date: 2025.11.11 ROHR INC

AI summary

An assembly for an aircraft propulsion system includes a fixed structure, a translating structure and a thrust reverser. The thrust reverser includes a blocker door, a structure link and a door link. The blocker door is pivotally coupled to the translating structure. The structure link includes a first structure link arm, a second structure link arm and a structure link mount connected to the first structure link arm and the second structure link arm. The first structure link arm and the second structure link arm are each pivotally coupled to the fixed structure. The first structure link arm and the second structure link arm laterally converge towards one another as the first structure link arm and the second structure link arm extend longitudinally towards the structure link mount. The door link extends longitudinally between and is pivotally coupled to the structure link mount and the blocker door.