Rotatable Wing Tip Hinge for Span Reduction and Flight Handling
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Solution Overview
Problem
The challenge is to design an aircraft wing configuration that balances weight, complexity, manufacturability, cost, and aerodynamic performance while ensuring adequate handling characteristics during low-speed and high-speed flight phases, particularly with movable wing tip devices that comply with airport clearance requirements.
Innovation Solution
Aircraft wing with a rotatable wing tip device attached via a hinge axis at an acute angle, actuated and restrained to various positions for optimal span reduction and incidence angle adjustment, allowing seamless transition between high-speed, low-speed, and ground configurations without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If leading edge or trailing devices such as slats, flaperons, or flow control devices are implemented on the movable wing tip device to ensure adequate margin at the outboard end of the wing during low-speed flight, then low-speed handling characteristics are improved, but weight and device complexity increase
Solution Approach 1:
The patent extracts the incidence angle adjustment function from complex leading edge or trailing devices and implements it through a simple hinge axis mechanism. The wing tip device rotates about the hinge axis to change its incidence angle relative to the wing, achieving low-speed handling improvement without adding slats, flaperons, or flow control devices. This reduces device complexity while maintaining the desired aerodynamic performance.
2Ease of operation
If wing chord section shapes are selected to improve low-speed margin, then low-speed handling characteristics are improved, but lift and drag performance during high-speed cruise is reduced, increasing fuel burn
Solution Approach 1:
The patent applies dynamics by making the wing tip device incidence angle variable rather than fixed. The wing tip device can rotate about the hinge axis to achieve different incidence angles: a higher incidence angle for low-speed flight to improve handling characteristics, and a lower incidence angle for high-speed cruise to optimize lift and drag performance. This dynamic adjustment eliminates the need to compromise between low-speed and high-speed performance with a fixed chord section shape.
3Adaptability or versatility
If the wing span is reduced in ground configuration to comply with airport clearance requirements, then airport operability is improved, but aerodynamic performance during flight may be compromised
Solution Approach 1:
The patent uses a dynamic, multi-position wing tip device that can rotate about a hinge axis to achieve different configurations. In ground configuration, the wing tip device rotates to reduce the overall wing span to comply with airport clearance requirements. During flight, the wing tip device rotates to optimal incidence angles that maintain aerodynamic performance. This dynamic reconfiguration allows the aircraft to adapt to different operational requirements without compromising performance in either regime.
4Device complexity
If a fixed wing configuration is used to maintain simple structure, then device complexity is reduced, but the ability to adapt to different flight phases and airport clearance requirements is limited
Solution Approach 1:
The patent segments the wing into a fixed wing portion and a movable wing tip device that can rotate independently about a hinge axis. This segmentation allows the wing tip device to be adjusted to different positions and incidence angles for different flight phases (low-speed flight, high-speed cruise, ground operations) while the main wing structure remains fixed and simple. The segmented design provides adaptability without requiring the entire wing structure to be complex and movable.
Data Source
AI summary
An aircraft including a wing with a fixed wing portion and a wing tip device rotatably hingedly attached at a fixed wing portion outboard end. The wing includes a wing fold mechanism configured to actuate the wing tip device to rotate relative to the fixed wing portion to at least three commanded and predetermined wing fold angles and to restrain rotational movement of the wing tip device at each commanded position. A first position corresponds to high-speed flying, a second position to ground-based operations and a third position to low-speed flying. The flying positions rotate the wing tip to a position where upper and lower wing tip surfaces are continuations of the upper and lower surfaces of the fixed wing, with a low-speed incidence angle being less than a high-speed incidence angle. The ground-based position reduces the wing span to the greatest degree of the three positions.