Variable Drogue Severance Delay for Ejection Seat Mode Transitions
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Solution Overview
Problem
Current ejection seat systems experience harsh mode boundary transitions, particularly between low airspeed, low altitude situations and higher airspeed, high altitude situations, leading to unstable ejection sequences and potential injury risks.
Innovation Solution
The implementation of a variable drogue severance delay, determined using polynomial, quadratic, or linear calculations, allows for smoother transitions between ejection modes by optimizing the timing of drogue parachute deployment and main parachute deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed timing sequences are used for parachute deployment, then the control system is simple, but mode transitions become harsh and unstable
Solution Approach 1:
The patent applies dynamics by transitioning from fixed timing sequences to variable timing sequences. The drogue severance delay is dynamically adjusted based on real-time ejection mode determination, allowing the system to adapt to different flight conditions and achieve smoother mode transitions while maintaining stability.
Solution Approach 2:
The patent changes the timing parameter from fixed to variable based on ejection mode. By determining the appropriate drogue severance delay according to the current ejection mode (first, second, or third mode), the system optimizes parachute deployment timing for each condition, reducing harsh transitions between modes.
2Reliability
If variable drogue severance delay is implemented, then mode transitions become smoother and safety improves, but calculation complexity increases
Solution Approach 1:
The patent implements parameter changes by calculating variable drogue severance delay based on ejection mode and flight conditions. Different mathematical models (polynomial, quadratic, or linear calculations) are applied depending on the specific ejection mode, optimizing safety while managing computational complexity through mode-specific approaches.
3Ease of operation
If fixed parachute deployment timing is used, then the system is easier to operate, but injury risks increase due to harsh mode transitions
Solution Approach 1:
The patent applies dynamics by making the parachute deployment timing adaptive rather than fixed. The system automatically adjusts the drogue severance delay based on real-time ejection mode determination, eliminating the need for manual intervention while reducing injury risks associated with harsh mode transitions.
Solution Approach 2:
The patent implements feedback by continuously monitoring ejection mode conditions and adjusting drogue severance delay accordingly. This closed-loop approach ensures that parachute deployment timing is optimized based on actual flight conditions, reducing injury risks while maintaining automated operation.
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 safety of ejection sequences, and prevents unnecessary injury risks by optimizing parachute deployment timing based on dynamic and static pressure data.
Implementation Method 1
The dynamic pressure is determined using at least one dynamic pressure sensor coupled to a pitot tube coupled to the ejection seat
Implementation Method 2
The static pressure is determined using a static pressure sensor coupled to the ejection seat
Implementation Method 3
Current ejection seats may include a pitot system, which collects dynamic air pressure data upon the air inlet of the pitot tube entering the airstream outside the cockpit
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 equivalent airspeed and an equivalent altitude of the ejection seat; and, responsive to the airspeed and the altitude indicating a second mode of operation: sending, by the processor, a command to deploy a drogue parachute; determining, by the processor, a variable drogue severance delay; and responsive to the variable drogue severance delay expiring, sending, by the processor, a command to sever the drogue parachute and deploy a main parachute.