Thrust Reverser Modulation for Idle Fuel Efficiency
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to being sized larger for take-off, leading to excessive thrust at idle speed, which is not optimal for cruise or landing conditions, resulting in fuel inefficiencies and potential arrival delays.
Innovation Solution
A thrust reverser assembly with a moveable portion and actuator assemblies that modulate air flow through a bleed passage, allowing for variable thrust settings, including intermediate positions between fully stowed and fully deployed, to reduce forward thrust and control airspeed, ground speed, and approach angle during landing approaches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is sized larger to provide sufficient power for take-off, then the take-off performance is improved, but the engine generates excessive thrust at idle speed during cruise and landing conditions, resulting in fuel inefficiency
Solution Approach 1:
The thrust reverser system is designed to be dynamically adjustable between fully stowed, intermediate, and fully deployed positions. The actuator assemblies enable continuous modulation of the moveable portion position, allowing the engine thrust to be dynamically controlled according to flight conditions, thereby resolving the contradiction between take-off power requirements and cruise fuel efficiency
Solution Approach 2:
The system changes the operational parameters of the engine by introducing variable thrust reverser positions. By modulating the moveable portion position parameter, the system transforms the engine output from a fixed high-thrust state to a variable thrust state, enabling optimal fuel efficiency during cruise while maintaining take-off capability
2Reliability
If the engine is sized larger to provide sufficient power for take-off, then the take-off performance is improved, but the engine produces more thrust than needed at idle speed during certain flight conditions, requiring additional speed control measures
Solution Approach 1:
The thrust reverser assembly provides dynamic speed control capability through intermediate positions. The actuator assemblies enable smooth transitions between thrust levels, allowing precise speed management during approach and landing without requiring discrete control actions or rerouting, thereby improving ease of operation
Solution Approach 2:
The thrust reverser system is segmented into multiple operational modes (fully stowed, intermediate positions, fully deployed). This segmentation allows independent control of thrust levels, enabling fine-grained speed management during different flight phases without affecting the overall engine configuration or requiring additional control systems
3Device complexity
If the thrust reverser assembly uses discrete positions only, then the system simplicity is maintained, but the ability to maintain precise target speeds during approach is limited
Solution Approach 1:
The system transitions from discrete to continuous position control. The actuator assemblies are designed to modulate the moveable portion position along a continuous range, enabling precise speed matching during approach while maintaining relatively simple system architecture through automated control logic
Solution Approach 2:
The control system incorporates feedback mechanisms to monitor aircraft speed and automatically adjust the thrust reverser position. This feedback loop enables precise maintenance of target speeds during approach by continuously comparing actual speed with desired speed and making real-time adjustments to the moveable portion position
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
Enables reduced forward thrust at idle power settings, improving fuel efficiency, accelerating during go-around scenarios, and maintaining lower flight speeds, thereby reducing mission fuel burn and arrival delays.
Implementation Method 1
A thrust reverser assembly with a moveable portion and actuator assemblies that modulate air flow through a bleed passage, allowing for variable thrust settings
Data Source
AI summary
Thrust reverser assemblies and a method of operating an aircraft during a landing approach mode of operation are provided. The thrust reverser assembly includes a moveable portion that is moveable over a continuous range of travel between a fully stowed position and a fully deployed position. Movement away from the fully stowed position opens a bleed passage. An actuator assembly coupled to the moveable portion is operable in an intermediate forward thrust mode to modulate a position of the moveable portion along the continuous range of travel, such that an air flow through the bleed passage is correspondingly varied. A throttle device includes a first position associated with deployment of, and a second position associated with engagement of, the intermediate forward thrust mode of operation. A drag flap assembly may extend from the bleed passage during the intermediate forward thrust mode of operation.