Variable Drogue Severance Delay for Ejection Seat Stability
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Solution Overview
Problem
Current ejection seat systems experience harsh mode boundary transitions, particularly between low airspeed, low altitude situations and high airspeed, high altitude situations, leading to unstable deployments and potential injury risks.
Innovation Solution
The proposed system introduces a graduated drogue deployment/parachute delay timing for 'fast' and 'high altitude' modes, along with a variable drogue severance delay, to optimize parachute deployment sequences based on airspeed and altitude thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fixed timing sequences are used for parachute deployment, then the system is simple to operate, but harsh mode boundary transitions occur leading to unstable deployments
Solution Approach 1:
The patent applies dynamics by transitioning from fixed timing sequences to variable timing sequences for parachute deployment. The controller adjusts the delay period between drogue parachute deployment and main parachute deployment based on real-time ejection mode determination, allowing the system to adapt dynamically to different flight conditions and eliminate harsh mode boundary transitions.
2Stability of the object's composition
If variable drogue severance delay is implemented, then deployment stability is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the timing parameters of parachute deployment based on ejection mode. The controller determines the appropriate delay period by evaluating flight parameters (such as altitude and airspeed) and selects from multiple predetermined time periods, thereby optimizing deployment stability without requiring complex mechanical modifications to the parachute system itself.
3Reliability
If fixed timing is used for main parachute deployment, then the system is reliable, but injury risks occur during mode transitions
Solution Approach 1:
The patent applies beforehand cushioning by implementing a variable delay period between drogue parachute deployment and main parachute deployment. This delay is predetermined based on ejection mode and serves to cushion the transition by allowing the drogue parachute to sufficiently reduce velocity before main parachute deployment, thereby preventing injury during mode transitions while maintaining system reliability.
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
This approach reduces the harshness of mode transitions, enhances the stability and safety of ejection seat deployments, and optimizes parachute deployment timing for various operational conditions.
Implementation Method 1
deploy a drogue parachute... decelerate the ejection seat and occupant to a velocity below a threshold velocity
Implementation Method 2
deploy a main parachute... decelerate the ejection seat and occupant to a velocity below a threshold velocity
Data Source
AI summary
A method is disclosed herein. The method includes receiving, by a processor, an ejection command for ejecting an ejection seat from an aircraft; determining, by the processor, an airspeed and an altitude of the ejection seat; responsive to the altitude of the ejection seat indicating a second mode of operation, determining, by the processor, whether the airspeed of the ejection seat is at or above a first threshold and below a second threshold; and responsive to the airspeed of the ejection seat being at or above the first threshold and below the second threshold: sending, by the processor, a command to deploy a drogue parachute; and, responsive to a first predetermined time period expiring, sending, by the processor, a command to deploy a main parachute and sever the drogue parachute based on a variable drogue severance delay.