Folding Wing Tip Hinge With Nested Actuator for Lower Drag
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Solution Overview
Problem
Folding wing tip devices on aircraft create additional drag due to large fairings required to cover protruding hinge arrangements, which affect aerodynamic performance and fuel efficiency.
Innovation Solution
A hinge arrangement using a geared rotary actuator (GRA) partially located within interface rings, allowing the wing tip device to be moved between flight and ground configurations with reduced protrusion, minimizing the need for a fairing and thus reducing drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional hinge arrangement with interleaved lugs is used, then the wing tip device can be moved between flight and ground configurations, but the hinge arrangement protrudes significantly beyond the wing skin requiring large fairings that increase drag
Solution Approach 1:
The hinge arrangement components are nested within the wing skin structure. The rotary actuator, lugs, and hinge mechanism are all contained within cavities formed in the wing skin, with only minimal protrusions extending beyond the wing surface. This nesting approach eliminates the need for large external fairings while preserving the wing tip device's ability to move between flight and ground configurations.
Solution Approach 2:
The hinge arrangement transitions from a traditional external configuration to an internal configuration by moving the mechanism into the third dimension (within the wing skin thickness). The rotary actuator and lugs are positioned within the wing skin's internal volume, utilizing the depth dimension to accommodate the mechanism without increasing the external footprint, thereby reducing drag.
2Extent of automation
If the hinge arrangement protrudes beyond the wing skin to accommodate the rotary actuator and lugs, then the wing tip device can be actuated, but the exposed section requires a fairing that reduces aerodynamic performance
Solution Approach 1:
The automated hinge arrangement components including the rotary actuator and lugs are nested within the wing skin structure. The mechanism is contained within internal cavities, with minimal protrusions beyond the wing surface that can be covered by small or no fairings, thereby preserving the aerodynamic shape and performance of the wing.
Solution Approach 2:
The wing skin is designed with localized cavities and recesses at specific positions where the hinge arrangement components are located. These local modifications to the wing skin structure allow the automated actuation mechanism to be housed internally, maintaining the overall aerodynamic shape while accommodating the necessary mechanical components.
3Reliability
If larger fairings are used to cover the protruding hinge arrangement, then the aerodynamic performance is maintained, but the drag on the aircraft increases reducing fuel efficiency
Solution Approach 1:
The hinge arrangement is nested within the wing skin structure, eliminating the need for large external fairings. This internal configuration maintains aerodynamic performance with minimal or no fairing required, thereby reducing drag and improving fuel efficiency while preserving the reliability of the wing tip device actuation system.
Solution Approach 2:
The harmful element (large fairing) is extracted from the design by nesting the hinge arrangement internally. By removing the need for large fairings through internal placement of the actuator and lugs, the design achieves both aerodynamic performance and fuel efficiency without compromising the functionality of the wing tip device actuation.
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 reduces drag and maintains aerodynamic efficiency by minimizing the size of the fairing needed to cover the hinge arrangement, enhancing fuel efficiency.
Implementation Method 1
a geared rotary actuator (GRA) partially located within the fixed wing interface ring and wing tip device interface ring, and arranged to drive the wing tip device interface ring to move the wing tip device between the flight configuration and ground configuration
Data Source
AI summary
The invention provides an aircraft wing with a wing tip device movable between a flight configuration for use during flight and a ground configuration for use during ground-based operations. In the ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced. A hinge arrangement connects the fixed wing and the wing tip device. The hinge arrangement comprises a plurality of fixed wing interface rings, a plurality of wing tip device interface rings, and a geared rotary actuator (GRA) partially located within the fixed wing interface rings and wing tip device interface rings. The GRA is arranged to drive the wing tip device interface rings to move the wing tip device between the flight configuration and ground configuration.