Active Flow Control on Aircraft Vertical Stabilizer
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Solution Overview
Problem
Conventional aircraft vertical tails are oversized due to the need to maintain stability and control during emergency situations, leading to increased weight and drag, making them costly and inefficient.
Innovation Solution
An active flow control system with actuators and sensors that selectively enhance airflow over the vertical tail, allowing for a reduced size while maintaining control throughout the designed flight envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the vertical tail is increased to maintain stability and control during emergency situations, then the aircraft's yaw control capability is improved, but the aircraft's weight and drag increase
Solution Approach 1:
The patent applies active flow control actuators that dynamically adjust airflow characteristics over the vertical tail surface. These actuators modify the boundary layer flow and delay flow separation, enabling a smaller vertical tail to generate sufficient yaw control forces during emergency conditions such as engine failures or high crosswinds.
Solution Approach 2:
The system changes airflow parameters (velocity, pressure distribution, boundary layer thickness) through active flow control actuators. By modifying these flow parameters, the vertical tail generates enhanced aerodynamic forces without increasing its physical size, resolving the contradiction between control capability and weight.
2Reliability
If the size of the vertical tail is increased to maintain stability and control during emergency situations, then the aircraft's yaw control capability is improved, but the aircraft's drag increases
Solution Approach 1:
Active flow control actuators dynamically manage airflow attachment over the vertical tail, delaying flow separation and reducing pressure drag. This allows a smaller vertical tail to maintain control effectiveness while generating less drag compared to a larger conventional tail.
Solution Approach 2:
By changing airflow parameters through active control, the system optimizes the pressure distribution over the tail surface, reducing wake turbulence and form drag while maintaining the necessary control forces for safety-critical flight conditions.
3Weight of moving object
If the size of the vertical tail is reduced to decrease weight and drag, then manufacturing and operating costs are reduced, but the aircraft's yaw control capability during emergency situations deteriorates
Solution Approach 1:
The patent replaces passive mechanical enlargement of the vertical tail with an active flow control system. Instead of increasing tail size mechanically to improve control, the system uses actuators to modify airflow characteristics, enabling a smaller tail to achieve the same or better control effectiveness.
Solution Approach 2:
Active flow control actuators modify boundary layer parameters and flow separation characteristics, allowing a reduced-size vertical tail to generate sufficient aerodynamic forces for yaw control during emergency conditions, thereby maintaining reliability while reducing weight.
4Weight of moving object
If the size of the vertical tail is reduced to decrease weight and drag, then manufacturing and operating costs are reduced, but the aircraft's yaw control capability during emergency situations deteriorates
Solution Approach 1:
The system substitutes passive structural enlargement with active flow control technology. A smaller vertical tail equipped with flow control actuators achieves the same drag-reduction benefits as a larger tail would provide passively, while maintaining control effectiveness through active airflow management.
Solution Approach 2:
By actively controlling airflow parameters over the reduced-size tail, the system minimizes flow separation and pressure drag, achieving lower overall drag compared to a larger conventional tail while maintaining necessary control forces for safety-critical operations.
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 enables a significant reduction in the size and weight of the vertical tail while maintaining performance, reducing drag and operational costs by selectively activating actuators to manage airflow and enhance forces as needed.
Implementation Method 1
the active flow control actuators alter one or more characteristics of the airflow over the surface
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Systems and methods described herein provide for the control of airflow over a vertical control surface of an aircraft to enhance the forces produced by the surface. According to one aspect of the disclosure provided herein, the vertical control surface of the aircraft is engaged by active flow control actuators that interact with the ambient airflow to alter one or more characteristics of the airflow. An actuator control system detects a flow control event, and in response, activates the active flow control actuators to alter the airflow. According to various aspects, the flow control event is associated with a separation of the airflow, which is corrected through the activation of the appropriate active flow control actuators, increasing the forces produced by the vertical control surface of the aircraft.