Angled Outboard Slat Edge for Winglet Vortex Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to maintain performance control while increasing winglet size on fixed-wing aircraft, as larger winglets introduce pitching and lift control issues due to non-linearities in pitching moment and lift coefficient, caused by flow separation induced by leading edge slats, which existing solutions either complicate with fly-by-wire control laws or incur costly design changes.
Innovation Solution
The configuration of the outboard slat on the aircraft wing, with a specific geometry including a leading edge, trailing edge, inboard edge, and outboard edge, where the outboard edge has a first and second side portion projecting onto the slat plane at defined angles, effectively directs the slat vortex inboard, reducing interference with the winglet and maintaining linear lift and pitching moment coefficients with angle of attack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If larger winglets are used to reduce drag, then fuel savings improve, but pitching and lift control problems worsen due to non-linearities caused by flow separation from leading edge slats
Solution Approach 1:
The patent modifies the geometric parameters of the outboard slat edge, specifically creating a multi-segmented configuration with defined angles (first angle between 0-45 degrees, second angle between 45-90 degrees) relative to the wing chord line. This parameter change alters the flow separation characteristics to maintain linear aerodynamic behavior with larger winglets
Solution Approach 2:
The invention applies a specific geometric configuration only to the outboard portion of the slat (the tip region), while the inboard portion maintains conventional design. This localized modification targets the specific area where vortex interference with winglets occurs, allowing larger winglets without affecting overall control performance
2Loss of energy
If larger winglets are installed to improve drag reduction, then fuel efficiency increases, but device complexity increases due to need for fly-by-wire control laws
Solution Approach 1:
The patent extracts and eliminates the source of the control problem by modifying the slat geometry to prevent vortex-induced non-linearities. This removes the need for complex fly-by-wire control laws, allowing larger winglets to be used with simpler conventional control systems
3Loss of energy
If winglet size is increased to reduce drag, then fuel savings improve, but the solution becomes costly once aircraft wing design is frozen
Solution Approach 1:
The invention modifies only the outboard edge geometry of the slat, which can be implemented as a standalone component change without requiring complete wing redesign. This localized modification is cost-effective even after initial wing design is frozen, as it involves minimal structural changes
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 allows for larger winglet sizes without performance issues, providing gradual airflow interference, maintaining lift and reducing undesirable pitch-up, while simplifying operational control and reducing weight, complexity, and maintenance compared to other solutions.
Implementation Method 1
the second side line extending toward the inboard edge as it extends toward the trailing edge... effectively directs the slat vortex inboard, reducing interference with the winglet
Implementation Method 2
caused in part by flow separation induced by interference of vortices created by the leading edge slats
Data Source
AI summary
A slat (50) for an aircraft wing comprises a leading edge (51) defining a leading edge line (61), a trailing edge (52) defining a trailing edge line (62), the leading and trailing edges line defining a slat plane, the chord distance (69) extending normal to the leading edge and measured along the slat plane; an inboard edge extending between the leading and trailing edges; and an outboard edge (56) extending between the leading and trailing edges. The outboard edge comprises a first side portion having a projection on the plane defining a first side line (63), and a second side portion having a projection on the plane defining a second side line (64), the second side line being disposed at a first angle to the first side line and at a second angle to the leading edge line as it extends toward the inboard and trailing edges. A wing assembly and an aircraft including the slat are also disclosed.