Aeronautical Thrust Reverser Flap Control Mechanism

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Solution Overview

Problem

Conventional thrust reversers for aircraft propulsion units, particularly grid thrust reversers, suffer from disruptions in the secondary flow due to connecting rods that extend radially between the fixed and movable structures, degrading propulsion performance and increasing fuel consumption.

Innovation Solution

A thrust reverser design featuring a fixed and movable external structure with a control mechanism that includes a return member connected via articulations to prevent the control mechanism from extending into the fluid flow conduit, using a telescopic drive rod to simplify geometry and reduce mass, and a shutter flap articulated to the movable structure to minimize interference and enhance deflection efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If connecting rods are used to link flaps to the fixed internal structure radially, then the flap deployment and retraction can be achieved, but the connecting rods extend into the fluid flow conduit and disrupt the secondary flow, degrading propulsion system performance

Engineering Contradiction:
Improveflap deployment and retraction controlVSAvoidfluid flow disruption
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the connecting rods from the fluid flow conduit by relocating them to the external structure. The flaps are now connected to the movable external structure rather than the fixed internal structure, allowing the control mechanism to be positioned outside the secondary flow path while maintaining flap actuation functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary mechanism where the movable external structure serves as the connection point between the control system and the flaps. This intermediary allows the control rods to be positioned externally while still transmitting the necessary motion to deploy and retract the flaps without interfering with the fluid flow.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If connecting rods extend radially into the fluid flow conduit to control flaps, then the control mechanism is simplified, but the propulsion system performance degrades due to flow disruption

Engineering Contradiction:
Improvecontrol mechanism structureVSAvoidpropulsion system performance
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The control mechanism is extracted from the internal fluid flow path and repositioned on the external structure. The connecting rods remain structurally simple but are now located outside the secondary flow conduit, eliminating their harmful interaction with the fluid while preserving the simplicity of the control mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-generated harmful factors

If the flap is articulated to the movable external structure, then the control mechanism can be positioned outside the fluid flow conduit, but the architecture becomes more complex

Engineering Contradiction:
Improvefluid flow disturbanceVSAvoidinverter architecture
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the flap articulation point with the movable external structure, combining the functions of flap support and flow path definition. This integration allows the control mechanism to be positioned externally while utilizing the existing movable structure as the articulation point, thereby minimizing additional architectural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design reduces fluid flow disturbances, minimizes fuel consumption, simplifies the architecture, and improves thrust reversal performance by maximizing deflection surface and reducing manufacturing costs, while maintaining robustness and aerodynamic efficiency.

Implementation Method 1

connected to the external movable structure by a first joint so as to permit rotation of the return member relative to the external movable structure around an axis of rotation of this first joint

Methodology Applied
Scientific EffectRotation around an axis:

Implementation Method 2

connected to the external fixed structure by a first connecting member configured so as to move the return member in rotation around the axis of rotation of the first joint

Methodology Applied
Scientific EffectMechanical motion transmission:

Implementation Method 3

connected to the flap by a second connecting member configured so as to move the flap towards the deployed position when the return member is moved in said first direction

Methodology Applied
Scientific EffectMechanical motion transmission:

Data Source

PatentEP4048883B1Thrust reverser with flaps controlled by a mechanism equipped with aeronautical bellcranks
Publication Date: 2024.03.20 SAFRAN NACELLES
  • EP4048883B1 patent drawingFigure 1~2
  • EP4048883B1 patent drawingFigure 3~4
  • EP4048883B1 patent drawingFigure 5~6

AI summary

The invention relates to an aeronautical thrust reverser (20) comprising a sliding cowl (25), shutter flaps (26) and deflection cascades (27). The reverser (20) comprises, for each flap (26), a return member (42) hinged to the sliding cowl (25), to a driving connecting rod (44) itself hinged to a front frame (22) of the reverser (20), and to a return connecting rod (46) itself hinged to the flap (26), the latter being moreover hinged by its rear end to the sliding cowl (25). The return member (42), the driving connecting rod (44) and the return connecting rod (46) form an actuation system (40) capable of opening the secondary flow duct (11B) in a direct thrust configuration.