Spanwise Slat Actuator Layout for Thin Wing Displacement
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Solution Overview
Problem
As aircraft wings become thinner to reduce drag, it becomes difficult to fit linear hydraulic slat actuators due to limited actuator displacement and the need for spar web penetration, especially in small aircraft wing airfoils.
Innovation Solution
A spanwise-oriented linear hydraulic slat actuator using a bell-crank mechanism is employed, where the bell-crank couples to a linear hydraulic slat actuator and an actuator output link, allowing the slat to move between retracted and extended positions via chordwise displacement, thus bypassing spar web penetration and enabling greater displacement within the wing architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the aircraft wing airfoil is made smaller to reduce drag, then the wing thickness decreases, but it becomes difficult to fit linear hydraulic slat actuators due to limited actuator displacement
Solution Approach 1:
The bell-crank mechanism transforms the actuator's spanwise motion (one dimension) into chordwise motion of the slat (another dimension). This dimensional transformation allows the actuator to be positioned spanwise within the thin wing while still achieving the necessary chordwise displacement for slat operation, resolving the contradiction between reduced wing thickness and adequate actuator displacement.
2Length of moving object
If a linear hydraulic slat actuator is installed in a thin aircraft wing, then the actuator displacement is limited, but penetration of front spar web is required to accommodate the actuator length
Solution Approach 1:
By reorienting the actuator to move spanwise and using the bell-crank to convert this motion to chordwise slat movement, the actuator can be positioned within the wing without requiring penetration of the front spar web. This eliminates the structural complexity and safety concerns associated with spar web penetration while maintaining adequate actuator displacement.
3Length of moving object
If the linear hydraulic slat actuator is oriented spanwise, then greater displacement is achieved within the wing architecture, but the actuator occupies space in the spanwise direction
Solution Approach 1:
The bell-crank mechanism enables the actuator to occupy spanwise space efficiently while delivering chordwise displacement. The actuator's spanwise orientation and motion are converted to chordwise slat movement, allowing the system to achieve greater effective displacement within the available wing architecture without excessively occupying spanwise volume.
Solution Approach 2:
The bell-crank acts as an intermediary mechanism that decouples the actuator's spanwise motion from the slat's chordwise movement. This intermediary allows the actuator to be positioned and oriented spanwise (occupying minimal spanwise space) while still achieving the necessary chordwise displacement through mechanical transformation.
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 solution allows for increased slat displacement within the aircraft wing while occupying less space, tailoring output displacement through bell-crank arm lengths, and avoiding spar web penetration.
Implementation Method 1
linear hydraulic slat actuator
Data Source
AI summary
An aircraft wing includes a fixed structure and a linear hydraulic slat actuator attached to the fixed structure. The linear hydraulic slat actuator is oriented spanwise along the aircraft wing. The aircraft wing also includes an actuator output link and a slat attached to the actuator output link. The aircraft wing also includes a bell-crank coupled to the linear hydraulic slat actuator and to the actuator output link. In response to spanwise movement of the linear hydraulic slat actuator, the bell-crank is configured to move the actuator output link in a different direction that enables the slat to move between a retracted position and an extended position.