Aircraft Tail Leading-Edge Protrusion for Low-Drag Stall Control
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Solution Overview
Problem
Existing aircraft tail surface configurations, such as vortex generators and fences, create undesirable drag due to vortices, which are beneficial for stall prevention but detrimental in cruise conditions, and are costly for commercial airliners.
Innovation Solution
A single protrusion is positioned on the leading edge of the tail surface, closer to the tip than the root, with lateral sides originating from different points along the span, optimizing airflow control with minimal drag impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vortex generators or fences are installed on the tail surface to control airflow and delay stall, then airflow control and stall prevention are improved, but drag increases due to vortex creation
Solution Approach 1:
The invention divides the tail surface into multiple zones along the span, with different protrusion configurations applied selectively. The leading edge features discrete protrusions at specific span positions rather than continuous coverage, segmenting the flow control function to reduce overall drag while maintaining effectiveness in critical regions.
Solution Approach 2:
The invention applies flow control protrusions with specific geometric characteristics at particular locations along the span, where the protrusion height, shape, and position are optimized for local flow conditions. This localized optimization ensures effective stall prevention where needed while minimizing drag in other regions.
2Reliability
If multiple vortex generators are installed across the tail span to delay stall, then stall prevention is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the essential flow control function from a full-span array of vortex generators and implements it through a reduced set of strategically positioned protrusions. By taking out only the critical span locations where flow control is most needed, the design achieves stall prevention with minimal device complexity.
Solution Approach 2:
The protrusions are designed to perform multiple functions: they control leading edge flow to prevent stall, influence spanwise flow distribution, and maintain effectiveness across various flight conditions. This multi-functionality reduces the need for additional specialized devices.
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
Enhances airflow control, improves side force coefficient by 5%, reduces aircraft weight and size, and decreases fuel consumption without increasing drag, thus improving fuel efficiency and reducing carbon emissions.
Implementation Method 1
The vortex generators typically represent discontinuities that create vortices. The purpose of these vortex generators is to create vortices in a controlled and predictable manner. Vortices are often undesirable because they produce drag, but the vortices these devices create are beneficial since they delay wing stall.
Implementation Method 2
These vortices help maintain a boundary layer of flowing air attached to the wing. Stall occurs when a wing reaches a high enough angle of attack that the airflow separates from its surface.
Data Source
AI summary
An aircraft tail including: a leading edge, a trailing edge, a tip and a root, and a single protrusion protruding from the leading edge, wherein the single protrusion protrudes from the leading edge only in a direction opposite to the trailing edge and is closer to the tip than to the root, and includes a first lateral side and a second lateral side that originate from different points of the leading edge along the tail span, wherein the first lateral side is closer to the tip than to the second lateral side, and the protrusion is entirely in a section of the leading edge between 50% and 95% of the tail span from the root.