Pneumatic Split Flap Actuation via Distributed Bladder System
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Solution Overview
Problem
Existing systems for actuating split flaps on aircraft wings face challenges such as increased drag, high cost, weight, and susceptibility to flutter and jamming due to complex mechanical linkages and low stiffness of small, thin flaps.
Innovation Solution
A pneumatic bladder system is used to actuate split flaps, providing distributed force for deployment and retraction, reducing the need for discrete mechanical supports and eliminating unsupported spans, thus minimizing flutter risks and allowing for continuous support along the flap's length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex mechanical linkage is used to actuate the split flap, then the flap can be actuated, but the device complexity increases and weight increases
Solution Approach 1:
The patent replaces the traditional mechanical linkage system with a pneumatic actuation system. Inflatable bladders positioned behind the split flap are inflated to deploy the flap and deflated to retract it, eliminating complex mechanical linkages, hinges, and actuators while maintaining reliable actuation functionality
Solution Approach 2:
The patent uses pneumatic pressure to inflate bladders that directly push the split flap into the deployed position. This pneumatic mechanism provides smooth actuation without mechanical contact points, reducing complexity and improving reliability
2Reliability
If discrete mechanical supports are used for the split flap, then the flap can be supported, but the weight increases and cost increases
Solution Approach 1:
The patent eliminates discrete mechanical supports by using a continuous flexible skin that spans the entire flap length. This skin provides structural support and aerodynamic continuity without requiring heavy mechanical mounting points or discrete support structures
Solution Approach 2:
The patent employs a flexible skin that covers the entire span of the split flap, providing both structural support and aerodynamic surface. This continuous film replaces discrete mechanical supports, reducing weight while maintaining flap stability and eliminating gaps that would cause drag
3Object-generated harmful factors
If the split flap is made thin to reduce drag, then the drag decreases, but the stiffness decreases leading to increased flutter risk
Solution Approach 1:
The patent uses a flexible skin that provides aerodynamic continuity across the flap surface, allowing the flap to be thin while maintaining structural integrity. The skin acts as a continuous load-bearing element that prevents flutter without requiring thick construction
Solution Approach 2:
The patent replaces rigid mechanical support structures with a flexible pneumatic system. The inflated bladders provide distributed support along the flap span, allowing thin construction while preventing flutter through continuous pneumatic pressure rather than discrete mechanical bracing
4Device complexity
If actuation is applied at discrete points, then the actuation mechanism is simpler, but the flap stiffness is insufficient leading to buzzing or fluttering
Solution Approach 1:
The patent divides the actuation system into multiple segmented bladders distributed along the span of the split flap. Each bladder provides localized pneumatic pressure, and collectively they provide continuous distributed support and actuation, eliminating flutter while maintaining relatively simple individual components
Solution Approach 2:
The patent replaces discrete mechanical actuation points with distributed pneumatic actuation through multiple bladders. This substitution provides continuous support along the flap span, eliminating the buzzing and fluttering that occurs with discrete mechanical actuation points
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 pneumatic actuation system reduces weight and cost, minimizes flutter and jamming concerns, and allows for tailored deployment angles to meet aerodynamic demands, while load alleviation and redundancy features ensure reliable operation under various conditions.
Implementation Method 1
Deployment of the split flap is actuated pneumatically by the inflatable bladder system. The pneumatic bladder provides distributed force to extend and retract the split flap.
Implementation Method 2
The array comprises first and second bays which are individually inflatable and adjacent to each other. The inflatable bays in any particular column can be inflated in sequence, thereby deploying the split flap in stages.
Data Source
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AI summary
A system for pneumatically actuating a split flap hingedly mounted near or at a trailing edge of an airfoil. The system includes a bladder system disposed between the split flap and the upper surface of the airfoil. The split flap is a small-chord (usually 1-3% of total wing chord) long-span lower panel which separates from the airfoil trailing edge by means of a hinge or a flexible lower skin. Deployment of the split flap is actuated pneumatically by the inflatable bladder system. The split flap may exist at a fixed wing trailing edge, a moving flap trailing edge, or an empennage trailing edge. The pneumatic bladder provides distributed force to extend and retract the split flap. This pneumatic approach eliminates extra drag, reduces cost and weight, and lessens flutter concerns.