Circulation Control Airfoil for Stall Roll Stability
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Solution Overview
Problem
Low-speed aircraft maneuverability is compromised due to flow separation and inadequate control authority, leading to safety concerns during stall conditions, as conventional control surfaces are insufficient to maintain control during take-off, climb, and landing.
Innovation Solution
The Roll Stability System (RSS) employs circulation control mechanisms with ducts and vectored airflow to provide enhanced control authority by differentially directing airflow through inlets and outlets on an airfoil, creating a roll moment to counteract stall-induced rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional control surfaces are used, then the aircraft structure is simple, but control authority is insufficient at low speeds
Solution Approach 1:
The patent employs pneumatic principles by using high-pressure air injected through circulation control holes to generate a high-velocity jet that adheres to the control surface. This pneumatic jet provides enhanced control authority at low speeds by creating a virtual extension of the control surface without requiring larger mechanical surfaces, thus resolving the contradiction between control force and structural simplicity.
Solution Approach 2:
The system changes the flow parameters (pressure, velocity, direction) of the air jet dynamically through circulation control mechanisms. By varying the injection pressure and flow rate, the control surface can generate different levels of control authority as needed, allowing the same structure to adapt to different flight conditions without requiring multiple control surface sizes.
2Force
If circulation control is activated to improve low-speed control, then control authority increases, but energy consumption increases
Solution Approach 1:
The circulation control system utilizes the aircraft's existing engine exhaust or dedicated compressor output that would otherwise be wasted energy. By redirecting this available high-pressure flow through the circulation control holes, the system generates additional control authority without requiring separate power sources or significantly increasing overall energy consumption.
Solution Approach 2:
The system dynamically adjusts the circulation control parameters (flow rate, pressure, injection timing) based on flight conditions and control需求的. During low-speed maneuvers where control authority is most needed, the system activates circulation control at optimal levels, and reduces or deactivates it during high-speed cruise, thereby managing energy consumption effectively while maintaining control capability when required.
3Force
If control surfaces are enlarged to improve control authority, then low-speed maneuverability improves, but drag increases
Solution Approach 1:
Instead of physically enlarging control surfaces, the patent uses pneumatic jets to create a virtual extension of the control surface. The high-velocity air jet adheres to the control surface and extends the effective aerodynamic influence beyond the physical boundary, generating additional control force without adding physical area that would increase drag.
Solution Approach 2:
The circulation control system adds a temporal and directional dimension to control surface operation. By injecting high-velocity jets that adhere and follow the control surface contours, the system effectively extends control influence in the flow direction without increasing the physical dimensions of the control surface, thereby avoiding additional drag.
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 RSS effectively enhances aircraft safety and control by producing sufficient roll moments during stall conditions and improving aerodynamic efficiency, allowing for stable banking and turning without significant reduction in lift-to-drag ratio, thus addressing the limitations of conventional control surfaces.
Implementation Method 1
The system employs circulation control mechanisms that utilize the Coanda effect to adhere a high velocity jet to a control surface
Implementation Method 2
ducts that permit airflow through a number—e.g. three—of inlets that are provided at or near the leading edge of a foil, such as an airfoil wing and channel it to one or more outlets at or near a downstream location of the foil
Data Source
AI summary
A method and system 10 for controlling fluid flow 12 in relation to a body or foil 14. The system 10 has one or more channels 16, at least some of which having an inlet port 18 and an outlet port 20 defined in the foil 14 through which at least some of the fluid 12 may flow. The inlet port 18 is defined adjacent to a leading edge region 22 of the foil 14 and the outlet port 20 is located in a another region 24 of the foil. Optionally, a differential vectoring means 24 provides a differential mass flow rate across the foil 14 to provide a resultant force that in one illustrative environment creates, enhances, or stops a rolling action of the foil 14.