Two-Leg Slat Inboard Edge Geometry for Lift and Stall Control
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Solution Overview
Problem
Existing leading edge slat configurations for fixed-wing aircraft do not provide sufficient maximum lift and delayed stall onset, limiting their performance during take-off and landing.
Innovation Solution
A slat configuration with a substantially hingewise first leg and a second leg extending from the first leg to the trailing edge, where the first leg is angled inwardly by up to 10 degrees and the second leg is angled streamwise, optimizing the inboard edge geometry to enhance lift coefficient and stall angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional slat configurations (hingewise or streamwise) are used, then the structure is simple, but the maximum lift coefficient and stall angle are insufficient
Solution Approach 1:
The inboard edge of the slat is segmented into two distinct legs: a first leg extending substantially hingewise and a second leg extending substantially streamwise. This segmentation allows each leg to perform its specific aerodynamic function, with the first leg controlling flow attachment and the second leg managing flow separation, thereby achieving higher maximum lift coefficient (0.1 to 0.25 increase) and delayed stall onset (2 to 4 degrees) while maintaining structural simplicity
Solution Approach 2:
Different portions of the slat inboard edge are given different orientations to optimize local aerodynamic performance. The first leg is angled inwardly by up to 10 degrees relative to the wing leading edge to promote favorable flow attachment, while the second leg extends streamwise to control flow separation. This local differentiation of geometry creates optimal flow conditions at critical locations, resolving the contradiction between simple structure and high lift performance
2Ease of manufacture
If conventional slat configurations are used, then manufacturing is easy, but stall onset occurs at lower angles of incidence
Solution Approach 1:
The inboard edge is divided into two legs with distinct orientations, where the first leg (hingewise) and second leg (streamwise) work together to delay stall onset by 2 to 4 degrees. This segmentation provides a straightforward manufacturing approach using standard forming techniques while achieving superior stall characteristics compared to conventional single-configuration slats
Solution Approach 2:
The geometry parameters of the slat inboard edge are optimized by introducing the two-leg configuration with specific angular relationships. The first leg angles inwardly by up to 10 degrees and the second leg extends streamwise, creating favorable flow conditions that reliably delay stall onset. These parameter changes are achieved through conventional manufacturing processes, maintaining ease of manufacture while significantly improving reliability
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 configuration increases the maximum lift coefficient by 0.1 to 0.25 and delays stall onset by 2 to 4 degrees, improving aircraft performance during take-off and landing without adding complexity or weight.
Implementation Method 1
A slat having a two-leg inboard edge consisting of a first leg and a second leg. The first leg extends substantially hingewise from the leading edge of the wing. The second leg extends substantially streamwise from the end of the first leg toward the trailing edge of the slat.
Data Source
Figure 1
Figure 2~5
Figure 3~4
AI summary
A slat (7) for fixed-wing aircraft that includes a leading edge (3), a trailing edge (5), a chord (C), and an inboard edge (6) that includes particular dimensions (C1, delta) to affect airflow over the wing (2).