Aircraft Thrust Reverser Overstowed Position Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The deployment sequence of turbojet engine thrust reversers with doors is not optimized for aborted takeoffs, leading to increased braking distance due to the time-consuming transition from the stowed to the deployed position.

Innovation Solution

A method for controlling the thrust reverser that involves decreasing the engine speed to a setpoint value below a first threshold, controlling the doors to the overstowed position, unlocking the locking device, and then deploying the doors to generate reverse thrust, allowing for a faster deployment sequence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the doors are brought into the overstowed position before deployment, then the locking system can be unlocked, but the deployment duration is increased

Engineering Contradiction:

Improvelocking system reliabilityVSAvoiddeployment duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The doors are brought into the overstowed position in advance before the actual deployment sequence begins. This preliminary action allows the locking system to be properly engaged and unlocked during the deployment, ensuring reliability while managing the timing of the deployment sequence

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the door positions through different phases: initially bringing doors to overstowed position for locking engagement, then transitioning to deployed position for thrust reversal. The door actuators and locking system coordinate their actions dynamically based on the deployment phase

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If the engine speed is decreased to enable door deployment, then the doors can be moved to overstowed position, but the reverse thrust availability is delayed

Engineering Contradiction:

Improvedoor deployment capabilityVSAvoidtime to reverse thrust availability

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The engine speed is decreased in advance to a setpoint below the first threshold value before the doors are deployed. This preliminary speed reduction creates favorable aerodynamic conditions that enable the doors to be moved to the overstowed and then deployed positions without excessive aerodynamic forces opposing the movement

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The engine speed parameter is changed from above the first threshold value to below it, fundamentally altering the aerodynamic forces acting on the doors. This parameter change enables the door deployment sequence to proceed successfully by reducing the aerodynamic resistance to door movement

Inventive Principle:

Principle #35Parameter changes

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 method reduces the braking distance during an aborted takeoff by enabling a faster deployment of the thrust reverser, as the doors can be brought into the deployed position sooner, and the reverse thrust is available more quickly.

Implementation Method 1

a first engine speed threshold value at which the aerodynamic forces being exerted on the doors are equal to the forces developed by the door actuators

Methodology Applied

Scientific EffectAerodynamic forces: Drag

Implementation Method 2

re-directing to the front of the turbojet engine at least a part of the gas flow generated by the combustion and/or a part of the cold air flow generated by a fan

Methodology Applied

Scientific EffectFlow redirection:

Implementation Method 3

A first end 10A of the S shaped hook 10 cooperates with a first locking hook 31A integral with one of the two doors and a second opposite end 10B of the S shaped hook 10 cooperates with a second locking hook 31B integral with the other door

Methodology Applied

Scientific EffectMechanical locking: Mechanical Fastener

Data Source

PatentUS12270357B2Method and system for controlling a thrust reverser of an aircraft

Publication Date: 2025.04.08 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A method for controlling a turbojet engine thrust reverser during an aborted aircraft takeoff, the thrust reverser including doors movable between a stowed position, an overstowed position and a deployed position; door actuators to move the doors between the stowed, overstowed and deployed positions; a device for locking the doors in the stowed position, moveable between a locking position and an unlocking position; and a lock actuator to move the locking device between the locking and unlocking positions. The method includes decreasing the engine speed of the turbojet engine by following a setpoint value below a first engine speed threshold value at which the aerodynamic forces being exerted on the doors are equal to the forces developed by the door actuators; controlling the door actuators to bring the doors into the overstowed position; controlling the lock actuator to bring the locking device into the unlocking position.