Underwing Flap Linkage Stowage for Drag Reduction
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Solution Overview
Problem
Conventional underwing-mounted trailing edge flaps for aircraft wings require fairings that increase parasitic drag, negatively impacting aerodynamic performance during cruise operations.
Innovation Solution
The design incorporates a flap that pivots between a stowed and deployed position with a bullnose that pivots relative to the flap, allowing the linkage assembly to be stowed within the wing, eliminating the need for fairings and reducing drag, while increasing wing area and camber for improved lift during takeoff and landing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional trailing edge flap with linkage assembly is mounted along the trailing edge of the wing, then the flap can be deployed to increase lift during takeoff and landing, but the linkage assembly requires a fairing covering that produces significant parasitic drag during cruise operations
Solution Approach 1:
The linkage assembly is extracted from the trailing edge region and relocated to the underwing region. This allows the flap to be actuated without requiring a fairing along the trailing edge, thereby eliminating the parasitic drag penalty during cruise while preserving the flap's lift-generating capability during takeoff and landing operations.
Solution Approach 2:
The linkage assembly is repositioned from a two-dimensional arrangement along the trailing edge to a three-dimensional arrangement in the underwing region. This spatial reconfiguration allows the linkage to operate clear of the airflow over the wing's lower surface, eliminating the need for a drag-producing fairing while maintaining full flap functionality.
2Object-generated harmful factors
If the flap is designed to pivot between stowed and deployed positions with the bullnose pivoting relative to the flap, then the linkage assembly can be stowed within the wing eliminating fairings, but the mechanism complexity increases
Solution Approach 1:
The linkage assembly is nested within the wing structure in the underwing region. When the flap is in the stowed position, the linkage is contained within the wing's internal volume. When the flap deploys, the linkage remains housed within the wing, keeping the external contour clean and eliminating the need for a fairing, thus reducing parasitic drag without excessive complexity increase.
Solution Approach 2:
The bullnose is designed to pivot relative to the flap during deployment, creating a dynamic configuration that allows the linkage to clear the wing's lower surface airflow path. This dynamic movement enables the linkage to be positioned optimally during operation while remaining stowed within the wing during cruise, reducing drag without requiring a permanent external fairing.
3Reliability
If the flap is positioned along the lower surface of the wing in the stowed position and deployed rearward of the trailing edge, then the wing area and camber are increased for improved lift, but the flap requires additional space and structural accommodation
Solution Approach 1:
The flap mechanism is relocated from the trailing edge plane to the underwing region, utilizing the third dimension (vertical space below the wing). This allows the linkage assembly to be positioned in previously unused volume, accommodating the mechanism without encroaching on the wing's aerodynamic surfaces or requiring additional external space, thereby maintaining clean airflow and reducing drag.
Solution Approach 2:
The flap linkage assembly is nested within the wing's internal structure in the underwing region. This efficient use of internal volume accommodates the mechanism without increasing the external dimensions of the wing or interfering with the aerodynamic surfaces, allowing the flap to achieve its full deployed length rearward of the trailing edge for maximum lift enhancement.
Data Source
AI summary
Underwing-mounted trailing edge flaps for wings of aircraft are disclosed. A flap pivotally coupled to the wing is movable between a stowed position located along a lower surface of the wing and a deployed position located rearward of a trailing edge of the wing. The flap includes a first edge, a second edge located opposite the first edge, a first surface extending between the first edge and the second edge, and a second surface located opposite the first surface and extending between the first edge and the second edge. The first edge is located rearward of the second edge when the flap is in the stowed position, and forward of the second edge when the flap is in the deployed position. A bullnose pivotally coupled to the flap at a location along the first edge pivots relative to the flap as the flap moves between the stowed and deployed positions.