Movable Trailing Edge Flow Turning for Uniform Exhaust Sheets
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Solution Overview
Problem
Conventional propulsion systems for aircraft are limited in their ability to efficiently turn the flow of air beyond 90 degrees, leading to insufficient thrust ratios and mechanical complexity, particularly during hover and forward flight modes, and result in noise pollution.
Innovation Solution
Aircraft propulsion systems incorporating arrays of ducted fans integrated into airfoils, with movable trailing edges and optimized ratios, enable uniform exhaust sheets and selective flow turning control, allowing for efficient transition between flight modes without mechanical pitch changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional propulsion systems use static or movable flaps to turn flow downstream of the propulsor, then flow turning capability is achieved, but the flow cannot be reliably turned more than 90 degrees and thrust efficiency becomes insufficient
Solution Approach 1:
The patent employs dynamically adjustable trailing edges that can be positioned at multiple discrete angles (e.g., 0°, 15°, 30°, 45°, 60°, 75°, 90°) to optimize flow turning for different flight modes. This dynamic positioning enables reliable flow turning beyond 90 degrees while maintaining thrust efficiency, resolving the contradiction between flow turning capability and thrust reliability.
Solution Approach 2:
The system changes the geometric parameters of the exhaust flow by adjusting the trailing edge angle and optimizing the ratio of exhaust height to propulsor diameter. By varying these parameters across different flight modes (hover, forward flight, takeoff, landing), the system achieves both high flow turning capability and reliable thrust efficiency.
2Reliability
If conventional systems mechanically change the pitch of open rotor or propeller to produce thrust efficiently in hover and forward flight modes, then thrust efficiency is improved, but mechanical complexity increases and noise pollution increases
Solution Approach 1:
The patent replaces the mechanical pitch change mechanism with an electronic control system that adjusts the trailing edge position to control flow direction. This substitution eliminates complex mechanical linkages and reduces noise pollution while maintaining thrust efficiency across different flight modes through electronic actuation of the trailing edges.
Solution Approach 2:
The invention extracts the pitch control function from the propeller mechanism and relocates it to the trailing edge control system. By separating these functions, the system eliminates the need for complex mechanical pitch change mechanisms while achieving the same thrust efficiency through flow direction control.
3Productivity
If conventional propulsion systems are used, then basic propulsion function is achieved, but non-uniform air flow occurs and flow turning efficiency is limited
Solution Approach 1:
The patent divides the exhaust flow control into multiple segmented trailing edges that can be independently positioned. This segmentation allows each trailing edge to be optimized for its local flow conditions, creating more uniform air flow across the entire exhaust sheet while maintaining basic propulsion function.
Solution Approach 2:
The trailing edges act as intermediary elements between the propulsor and the exhaust flow. By positioning these intermediaries at specific angles, the system transforms non-uniform flow into uniform flow while maintaining propulsion efficiency, resolving the contradiction between productivity and flow uniformity.
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
The system achieves efficient flow turning and thrust generation across various flight modes, reducing noise pollution and mechanical complexity while maintaining high lift and thrust efficiency.
Implementation Method 1
movable trailing edges... control flow turning over the trailing edge
Implementation Method 2
produce a uniform exhaust sheet of air flow generated by the propulsors or propulsion systems and control flow turning over the trailing edge
Data Source
AI summary
An aircraft may comprise propulsors. The propulsors may be integrated into an array of propulsors. An array of propulsors may be integrated in an airfoil of the aircraft. The aircraft may include a flow turning control system. The flow turning control system may include an end wall and one or more movable flaps. The flow turning control system may enable selective flow turning of the flow of propelled by the array of propulsors. The selective flow turning may include actuating the one or more movable flaps. The selective flow turning may achieve flow turning of over a trailing edge of a movable flap.