Asymmetric Yoke for Aircraft Evacuation Slide Deployment
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Solution Overview
Problem
Inflatable evacuation slides deployed in high lateral wind conditions can 'kite' off the ground, preventing safe evacuation due to wind lift, especially when located near aircraft engines, as they fail to maintain contact with the exit surface.
Innovation Solution
A deployment assembly with asymmetric yokes that allows the forward portion of the slide to inflate and unfold faster than the aft portion, ensuring the toe end contacts the exit surface first, reducing the likelihood of kiting by creating a downward force and negative lift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the slide is deployed in high lateral wind conditions, then the slide can evacuate passengers under emergency conditions, but the wind causes the slide to kite off the ground, rendering it less usable and potentially blocking the aircraft exit
Solution Approach 1:
The asymmetric yoke is configured to cause the forward portion of the slide to inflate and unfold faster than the aft portion before full deployment. This preliminary asymmetric inflation sequence creates downward force and negative lift that counteracts wind-induced kiting during the critical early deployment phase when the slide is most vulnerable to lateral winds
Solution Approach 2:
The yoke is designed with asymmetric strap lengths where the first strap is longer than the second strap. This asymmetry causes the forward portion of the slide to deploy before the aft portion, creating a controlled deployment sequence that generates downward aerodynamic force to prevent the slide from kiting off the ground in high wind conditions
2Ease of operation
If the slide lifts off the ground above the airplane's door sill height, then the slide may block the aircraft exit, but maintaining ground contact in windy conditions is difficult
Solution Approach 1:
The asymmetric yoke creates preliminary downward force during the inflation sequence by causing the forward portion to deploy first. This preliminary action establishes ground contact before full inflation occurs, preventing wind lift from causing the slide to rise above the door sill height and block the aircraft exit
3Adaptability or versatility
If the slide is located near a forward end of an aircraft engine, then space is utilized efficiently, but any kiting could lead to contact with the engine
Solution Approach 1:
The asymmetric yoke design converts the harmful effect of wind-induced inflation into a beneficial downward force. By creating negative lift during deployment, the system uses the inflation process itself to counteract kiting and prevent engine contact, turning what would be a dangerous lifting force into a protective downward force that ensures safe clearance from the engine
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 prevents kiting of evacuation slides in windy conditions by ensuring the slide maintains contact with the ground, ensuring safe passenger evacuation and avoiding engine contact.
Implementation Method 1
allows the forward portion of the slide to inflate and unfold faster than the aft portion, ensuring the toe end contacts the exit surface first, reducing the likelihood of kiting by creating a downward force and negative lift
Data Source
Figure 1
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Figure 3A~3C
AI summary
An evacuation assembly may comprise an evacuation slide (110) and a first yoke coupled to the evacuation slide. The first yoke may comprise a first strap (182) and a second strap (184). The first strap may be longer than the second strap. The evacuation assembly may optionally include a second yoke coupled to the evacuation slide. A first strap of the second yoke may be longer than a second strap of the second yoke.