Mini-spoilers for Aircraft Lateral Control Surfaces
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Solution Overview
Problem
Lateral-control surfaces on aircraft wings experience adverse aerodynamic effects, such as flow separation and reversal of intended control responses, at high subsonic Mach numbers due to transonic flow features, leading to inefficiencies and potential dead-bands in roll and yaw control.
Innovation Solution
The implementation of mini-spoilers, which are movable surfaces located on or forward of the lateral-control surfaces, that are actuated independently or mechanically slaved to the lateral-control surfaces, to manage flow separation and reattachment, thereby maintaining effective control at small upward deflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lateral-control surfaces are deployed at small upward deflections at high subsonic Mach numbers, then roll and yaw control is provided, but adverse aerodynamic effects occur including flow separation and reversal of intended control response
Solution Approach 1:
The lateral-control system is segmented into two independent components: the primary lateral-control surface and the mini-spoiler. This segmentation allows each component to perform its specific function - the lateral-control surface provides primary roll/yaw control while the mini-spoiler manages flow separation independently, preventing adverse interactions between the two components at high Mach numbers
Solution Approach 2:
The mini-spoiler acts as an intermediary element between the free stream flow and the lateral-control surface. By deploying the mini-spoiler at small deflections, it modifies the local flow field ahead of the lateral-control surface, preventing shock-induced flow separation and maintaining smooth flow attachment, thereby eliminating the dead-band and reversal effects
2Speed
If lateral-control surfaces operate at high subsonic Mach numbers with transonic flow features, then flight performance is maintained, but strong shock waves cause flow separation and adverse aerodynamic effects
Solution Approach 1:
The mini-spoiler is deployed in advance of the lateral-control surface at small deflections to preemptively manage the flow field. By creating a controlled disturbance ahead of the main control surface, the mini-spoiler prevents the formation of strong shock waves and flow separation before they can affect the lateral-control surface effectiveness
Solution Approach 2:
The system changes the flow parameters locally by deploying the mini-spoiler, which modifies the pressure distribution and flow velocity ahead of the lateral-control surface. This parameter change prevents the transition to transonic flow conditions that would otherwise cause shock wave formation and flow separation at high Mach numbers
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 mini-spoilers enhance the effectiveness of lateral-control surfaces by eliminating adverse aerodynamic effects and maintaining lift and control responses, even at small upward deflections, thereby improving the overall control authority of the aircraft.
Implementation Method 1
strong shock waves can develop causing flow separation
Data Source
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AI summary
Mini-spoilers for enhancing the effectiveness of lateral-control surfaces of aircraft wings are described. An example aircraft includes a wing (800), a lateral-control surface in the form of an aileron (132), a flaperon or a spoiler, as well as a mini-spoiler (808). The lateral-control surface is movably coupled to the wing. The lateral-control surface is movable between a neutral position, a first upward deflected position, and a second upward deflected position extending beyond the first upward deflected position. The mini-spoiler is located on or forward of the lateral-control surface. The mini-spoiler is movable between a retracted position and a deployed position. The mini-spoiler is configured to be moved from the retracted position to the deployed position based on the lateral-control surface being moved from the neutral position to or toward the first upward deflected position.