Offset Thrust Reverser Doors for Crosswind Stability
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Solution Overview
Problem
Conventional thrust reversers on aircraft propulsion assemblies cause asymmetric air flow during crosswind landings, leading to reduced stability and controllability due to inadequate air supply to the vertical tail, resulting in potential loss of stability and controllability.
Innovation Solution
A thrust reverser design with offset downstream edges on the lower and upper doors, allowing a deflection opening that redirects a portion of the fluid upwards, increasing pressure and speed near the vertical tail, thereby enhancing stability and controllability by optimizing air flow distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional thrust reversers redirect air flows through reversal openings, then counter-thrust is generated for braking, but asymmetric air flow occurs during crosswind landings causing loss of stability and controllability
Solution Approach 1:
The air flow is divided into multiple portions: a first portion is redirected upstream through reversal openings to generate counter-thrust, while a second portion exits through a deflection opening to pressurize the vertical tail. This segmentation allows simultaneous achievement of braking force and stability maintenance.
Solution Approach 2:
Different regions of the air flow are treated differently: the first portion (through reversal openings) provides braking force, while the second portion (through deflection opening) provides stabilizing pressure on the vertical tail. Each portion serves a specific local function to resolve the contradiction.
2Productivity
If doors are opened to redirect air for thrust reversal, then braking capability is improved, but air supply to the vertical tail is reduced causing loss of controllability
Solution Approach 1:
The air flow is divided into multiple portions: a first portion is redirected upstream through reversal openings to generate counter-thrust, while a second portion exits through a deflection opening to pressurize the vertical tail. This segmentation allows simultaneous achievement of braking force and stability maintenance.
Solution Approach 2:
The deflection opening acts as an intermediary structure that captures the second portion of air flow and redirects it to pressurize the vertical tail region, ensuring that controllability is maintained even during aggressive thrust reversal operations.
3Force
If air flow is redirected through reversal openings, then counter-thrust is generated, but asymmetric trajectories cause uneven air distribution on tail surfaces
Solution Approach 1:
The air flow is divided into multiple portions: a first portion is redirected upstream through reversal openings to generate counter-thrust, while a second portion exits through a deflection opening to pressurize the vertical tail. This segmentation allows simultaneous achievement of braking force and stability maintenance.
Solution Approach 2:
The deflection opening is positioned and sized to compensate for the asymmetric air flow trajectories caused by crosswind conditions, creating a controlled asymmetric flow pattern that restores uniform air distribution on the tail surfaces.
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 design improves the pressurization of the tailfin and control surface, enhancing aircraft stability and controllability, especially during crosswind landings, by directing a second portion of the fluid axially downstream and vertically upwards.
Implementation Method 1
the downstream edge of the lower door and the downstream edge of the upper door defining, when the lower and upper doors are in the open position, a deflection opening configured to allow a second portion of said fluid to exit the reverser through this deflection opening
Implementation Method 2
redirect at least a fraction of the fluid thus evacuated towards a front end of the fixed structure in order to generate counter-thrust
Implementation Method 3
the lower and upper doors in the closed position being configured to be able to guide a fluid flowing in the conduit to its ejection outlet in order to generate a thrust
Data Source
AI summary
A thrust reverser for an aircraft propulsion assembly, this reverser including a lower door and an upper door defining, in thrust reversal configuration, a deflection opening, through which a portion of the fluid not serving to produce the thrust reversal of the aircraft can exit the reverser downstream. The downstream edge of the lower door is offset towards the rear with respect to the downstream edge of the upper door so as to orient the fluid flow passing through the deflection opening vertically upwards. When the propulsion assembly is mounted at the rear portion of the fuselage of the aircraft, this makes it possible in particular to improve the supply of the control surface of the aircraft in the landing phase, in particular in crosswind conditions.