Movable Vane Cascade for Variable Reverse Thrust Control
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Solution Overview
Problem
Aircraft turbofan engines with reverse thruster systems cannot produce a net reverse thrust to move an aircraft in reverse direction when parked, as known cascade systems either divert all or none of the thrust, limiting their ability to control and vary reverse thrust effectively.
Innovation Solution
The introduction of a cascade apparatus with movable vanes that intersect fixed vanes to form a reverse thrust flow path, allowing the movable vanes to slide relative to the fixed vanes between different positions to vary the reverse thrust, enabling precise control and adjustment of reverse thrust levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a cascade system is used to redirect airflow for reverse thrust, then reverse thrust is produced to reduce forward thrust, but the net thrust remains forward and cannot move the aircraft in reverse direction
Solution Approach 1:
The patent applies the dynamics principle by introducing movable vanes that can slide between fixed vanes to dynamically adjust the reverse thrust flow path. This allows the cascade system to vary the reverse thrust level continuously, enabling the aircraft to be moved in reverse direction from a stationary position while maintaining adaptability for different operational requirements.
2Ease of operation
If movable vanes are introduced to vary reverse thrust, then precise control of reverse thrust levels is achieved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the cascade system into fixed vanes and movable vanes that can independently slide along the flow path. This segmentation enables precise control of reverse thrust levels while maintaining a relatively simple overall structure, as each vane segment can be controlled separately to achieve the desired thrust variation.
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 an aircraft to be moved in reverse from a stationary position, reducing brake wear and allowing independent control of each engine's thrust zone, facilitating better maneuverability and reduced reliance on tow tractors.
Implementation Method 1
A plurality of movable vanes intersects the fixed vanes to form a reverse thrust flow path and are slidably coupled to the fixed vanes via the slots. The movable vanes slide relative to the fixed vanes between a first position to provide a first reverse thrust and a second position to provide a second reverse thrust different from the first reverse thrust.
Data Source
AI summary
Methods and apparatus to vary reverse thrust of turbofans are disclosed. An example cascade apparatus disclosed herein includes a fixed frame having a plurality of fixed vanes coupled to the frame, where each of the fixed vanes defines a plurality of slots. A plurality of movable vanes intersects the fixed vanes to form a reverse thrust flow path and slidably coupled to the fixed vanes via the slots. The movable vanes slide relative to the fixed vanes between a first position to provide a first reverse thrust and a second position to provide a second reverse thrust different from the first reverse thrust.