Adjustable Multi-Segment Nacelle Chine for Vortex Control
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Solution Overview
Problem
Conventional aircraft nacelle chines lack the ability to actively adjust and tune the position and strength of the vortex generated during flight, providing only near-binary control, which limits their effectiveness in improving near-stall pitch control and maximizing wing lift capacity.
Innovation Solution
The implementation of a multi-segment chine system that is translatable and adjustable relative to the nacelle, allowing for granular adjustment of the vortex position and strength through a controlled movement mechanism, enhancing aerodynamic performance by optimizing vortex interaction with the wing boundary layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fixed chines are installed on the nacelle, then vortex generation capability is improved, but aerodynamic drag increases
Solution Approach 1:
The chine is made adjustable relative to the nacelle, allowing it to change position between deployed and stowed configurations. This dynamic adjustment enables the chine to generate vortices when needed (improving reliability) while minimizing drag during cruise by being retracted (reducing harmful factors).
Solution Approach 2:
The position of the chine relative to the nacelle is changed as a variable parameter. By adjusting the chine's location along the nacelle surface, the system optimizes vortex generation at high angles of attack while reducing aerodynamic drag at low angles of attack through parameter variation.
2Reliability
If fixed chines extend outwardly into the airflow, then flow separation control is improved, but operating efficiency deteriorates
Solution Approach 1:
The chine transitions from a fixed static structure to a dynamic adjustable structure. During takeoff and landing, the chine is deployed to control flow separation and improve lift. During cruise, the chine is retracted to minimize interference with airflow and maintain operating efficiency.
Solution Approach 2:
The chine is periodically deployed and retracted based on flight conditions. It extends outwardly into the airflow during high angle of attack phases (takeoff, landing, stall recovery) to control flow separation, then retracts during low angle of attack cruise flight to preserve operating efficiency.
3Reliability
If conventional binary control chines are used, then vortex generation is achieved, but adjustability of vortex position and strength is limited
Solution Approach 1:
The chine is divided into multiple segments that can be independently adjusted relative to the nacelle. This segmentation allows granular control over the vortex generation characteristics, enabling precise adjustment of both vortex position and strength by varying the configuration of different segments.
Solution Approach 2:
The chine system transitions from binary (deployed/stowed) to continuous multi-position adjustment. Each segment can be positioned at different locations along the nacelle, providing dynamic control over vortex generation parameters including position and strength, thereby improving adaptability to various flight conditions.
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
This solution improves near-stall pitch control and increases the maximum coefficient of lift by allowing precise adjustment of the vortex generated by the chine, thereby enhancing aircraft performance during various flight conditions.
Implementation Method 1
The chine is typically mounted on a side of the nacelle and is sized and positioned to control the separation of the flow over the wing by generating a vortex that interacts beneficially with a boundary layer of the upper surface of the wing
Implementation Method 2
generating a vortex that interacts beneficially with a boundary layer of the upper surface of the wing in order to reduce flow separation
Implementation Method 3
the first segment is translatable relative to the nacelle along the fore-aft direction
Data Source
AI summary
Aircraft nacelles having adjustable chines are described. An example apparatus includes a multi-segment chine coupled to a nacelle. The multi-segment chine includes a first segment and a second segment. The first segment is oriented along a fore-aft direction. The first segment is translatable relative to the nacelle along the fore-aft direction. The first segment includes one or more first airflow openings. The second segment is fixedly coupled to the nacelle. The second segment is oriented along the fore-aft direction. The second segment includes one or more second airflow openings. The second segment is substantially coplanar with the first segment. Translation of the first segment adjusts the transverse alignment of the first airflow openings with the second airflow openings to vary an allowable airflow through the multi-segment chine.