Wing Control Tabs for Rapid Stall Mitigation at High Angle of Attack
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Solution Overview
Problem
The onset of stall in aircraft wings is difficult to predict due to various factors influencing the angle of attack, leading to potential stalling outside the usual flight envelope.
Innovation Solution
An aircraft wing design with moveable flight control surfaces and tabs that deploy differentially at a threshold angle of attack, using faster-moving tab drive systems to mitigate stall by altering wing loading, increasing the stall angle or moving stall to less susceptible areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the aircraft operates at higher angles of attack to expand the flight envelope, then the aircraft can achieve higher performance, but the risk of wing stall increases
Solution Approach 1:
The tab drive systems are configured to deploy tabs in advance when the angle of attack approaches the stall threshold, before actual stall occurs. This preliminary action modifies the wing loading distribution proactively, preventing stall from developing while allowing the aircraft to operate at higher angles of attack within the expanded flight envelope.
Solution Approach 2:
The invention applies differential tab deflections at specific locations along the wing span rather than uniform control surface movement. By locally modifying the airflow and loading characteristics at critical stall-prone areas, the system prevents stall propagation while maintaining overall flight control and expanding the safe operating envelope.
2Speed
If traditional flight control surfaces are used alone, then the control system is simple, but the response speed is insufficient to prevent rapid stall progression
Solution Approach 1:
The control system is segmented into two independent subsystems: traditional flight control surfaces for primary control and separately actuated tabs for rapid stall prevention. The tabs can be deployed independently and much faster than the main control surfaces, providing a dedicated high-speed response mechanism without requiring complete redesign of the existing control system.
Solution Approach 2:
The tabs serve as an intermediary element between the pilot's control inputs and the wing airflow. They provide a secondary, faster-acting control mechanism that mediates the interaction between the slower main control surfaces and the aerodynamic stall condition, bridging the response time gap.
3Reliability
If tabs are deployed to mitigate stall, then the stall angle of attack increases, but the system complexity increases with additional drive systems
Solution Approach 1:
The tab drive systems are designed with dynamic actuation capabilities, allowing the tabs to be deployed only when needed (when angle of attack approaches stall threshold) rather than remaining static or continuously actuated. This dynamic deployment reduces the effective complexity by engaging the additional system only under specific critical conditions.
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 solution effectively extends the flight envelope by preventing rapid stall progression, enhancing aircraft performance and safety by optimizing tab deflections based on experimental data.
Implementation Method 1
As stalling relates to the separation of flow over the wing surface, stalling is more likely to occur at higher angles of attack of the wings
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5C
AI summary
An aircraft wing with an array of moveably flight control surfaces (20), each flight control surface (20) having a trailing edge (16) with a moveable tab (15) attached to the flight control surface trailing edge (16). A flight control system coupled to a flight control surface (20) drive system which moves the flight control surfaces (20); a tab drive system which moves the moveable tabs (15) and one or more aircraft angle of attack sensors. The flight control system stores a set of angular deflections to deflect the tabs upwardly when the angle of attack reaches a threshold.