Pivoting Air Inlet Members for Aircraft Thrust Reversal

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Solution Overview

Problem

Existing aircraft propulsion systems face challenges in achieving efficient thrust reversal during landing without increasing mass, size, or disrupting aerodynamics, particularly due to airflow attachment issues and complex designs in current thrust reversal systems.

Innovation Solution

An air intake with movable components that pivot between cover and deflection positions to guide or deflect airflow, allowing for efficient thrust reversal while maintaining aerodynamic performance and minimizing size and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional air inlet with fixed geometry is used, then the structure is simple and reliable, but the thrust reversal capability is limited and requires separate mechanical systems

Engineering Contradiction:
Improvethrust reversal capabilityVSAvoidinlet structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the inlet geometry variable through mobile members (flaps or doors) that can change position. These mobile members are disposed within the inlet and can be moved between a first position (normal operation) and a second position (thrust reversal), allowing the inlet to adapt its geometry dynamically based on operational requirements. This eliminates the need for separate mechanical thrust reversal systems while providing both normal operation and thrust reversal capabilities through a single integrated structure.

Inventive Principle:
Principle #15Dynamics

2Productivity

If mobile members are added to promote thrust reversal, then the thrust reversal efficiency improves, but the risk of foreign object damage increases

Engineering Contradiction:
Improvethrust reversal efficiencyVSAvoidresistance to foreign object damage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies the beforehand cushioning principle by providing a housing that receives the mobile members and protects them from foreign object damage. The housing is configured to shield the mobile members (flaps or doors) during operation, preventing direct exposure to foreign objects such as birds or debris. This protective housing ensures that the mobile members, which are critical for thrust reversal efficiency, remain reliable and undamaged while still being able to move between positions to enable effective thrust reversal.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If the inlet geometry is made variable for thrust reversal, then the aerodynamic performance during reversal improves, but the control complexity increases

Engineering Contradiction:
Improveaerodynamic performance during thrust reversalVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies the merging principle by integrating the mobile members directly into the inlet structure itself, rather than using separate control systems. The mobile members (flaps or doors) are disposed within the inlet and are controlled to move between positions, with their movement directly altering the inlet geometry. This integration simplifies the control system by combining the geometry-changing function and the thrust reversal function into a single mechanism, reducing the number of separate components and control systems needed while maintaining excellent aerodynamic performance during thrust reversal.

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

The air intake enhances thrust reversal performance by detaching the reverse airflow from the inner wall, preventing airflow loops, and preserving aerodynamics, thus improving braking efficiency and reducing unwanted airflow circulation.

Implementation Method 1

mobile members (14) arranged inside said air inlet (12) and configured to be movable between a first position and a second position, in which the first position promotes a forward thrust phase of the aircraft and the second position promotes a thrust reversal phase of the aircraft

Methodology Applied
Scientific EffectThrust reversal: Reaction (physics)

Data Source

PatentEP4355987B1Air inlet for an aircraft propulsion unit comprising mobile members for promoting a thrust reversal phase, and method for using such an air inlet
Publication Date: 2026.04.29 SAFRAN AIRCRAFT ENGINES SAS
  • EP4355987B1 patent drawingFigure 1A~2A
  • EP4355987B1 patent drawingFigure 2B~3A
  • EP4355987B1 patent drawingFigure 3B~4

AI summary

The invention relates to an air inlet (1) of an aircraft propulsion unit (8) comprising thrust reversal means configured to modify a bypass air flow circulating from upstream to downstream in a bypass duct (6) into a reverse air flow (F-INV) circulating from downstream to upstream, the air inlet (1) comprising an interior wall (10) comprising openings (14) and, in each opening (14), a mobile member (2) that comprises a covering wall (20) and a deflecting wall (21) and is mounted so as to pivot between a covering position, in which the covering wall (20) obstructs the opening (14) so as to guide the bypass air flow and promote a thrust phase, and a deflecting position (P2), in which the deflecting wall (21) obstructs the opening (14) so as to separate the reverse air flow (F-INV) and promote a thrust reversal phase (B).