Flaperon Linkage Jam Protection via Segmented Fusing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional flight control surface actuators are prone to jamming due to obstructions, which can lead to loss of functionality and collateral damage, posing risks to safe flight and landing.
Innovation Solution
The implementation of a jam-tolerant mechanism with structural fusing capabilities, runout clearance, shielded linkages, and cam surface designs that prevent pinching jams, allowing continued operation even with obstructions by shearing weakened fasteners and providing extra space for obstructions to be pushed out of the cam track.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional linkage mechanisms with cam tracks are used to actuate flight control surfaces, then precise control and coordinated movement are achieved, but obstructions can cause jamming leading to loss of functionality and collateral damage
Solution Approach 1:
The linkage is divided into multiple separable segments connected by fusable joints. When an obstruction causes excessive force, weak links with fusable joints break the continuous linkage into isolated segments, preventing the obstruction from propagating damage throughout the entire mechanism while maintaining actuator functionality.
Solution Approach 2:
Fusable joints act as intermediary elements between the actuator and the control surface linkage. These joints include weak links designed to fail under obstruction loads, serving as a mediator that protects the primary actuator and control surface from direct damage while allowing the system to maintain operational capability.
2Reliability
If the linkage mechanism is made robust to prevent jamming, then resistance to obstruction increases, but the weight and complexity of the mechanism increase
Solution Approach 1:
Instead of making the entire linkage mechanism uniformly robust, weak links with fusable joints are strategically placed at specific locations where obstruction forces are most likely to occur. This localized approach provides obstruction resistance only where needed, minimizing the addition of unnecessary weight and complexity to the overall mechanism.
Solution Approach 2:
The weak links are designed as sacrificial, disposable components that are intentionally made weaker than other linkage elements. When an obstruction occurs, these cheap, easily replaceable links break to protect the more critical and expensive components, avoiding the need to over-engineer the entire mechanism for extreme obstruction resistance.
3Measurement precision
If the linkage mechanism is designed to be rigid for precise control, then control precision improves, but the mechanism becomes more susceptible to jamming from obstructions
Solution Approach 1:
The rigid linkage is segmented into multiple rigid sections connected by fusable joints. Each segment maintains the precision and rigidity needed for accurate control surface positioning, while the fusable joints between segments provide a failure mode that prevents complete jamming, thus maintaining both control precision and jam tolerance.
Solution Approach 2:
The fusable joints are pre-designed with controlled weakness to cushion against obstruction forces before they can compromise the rigid linkage segments. This beforehand cushioning allows the rigid segments to maintain their precision-control properties while being protected from the harmful effects of obstructions.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A flaperon mechanism that provides jam protection while preventing the component departing from the airplane or causing unacceptable collateral damage. The jam protection feature comprises a controlled failure (fused) mechanism that is associated with the flaperon and flaperon hinge panel and maintains functional movement of the devices. Additional features can be added to the mechanism to block, shield, allow runout and shed other obstruction avenues.