Variable Thrust Ejection Catapult for Weight-Adaptive Occupant Safety

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Solution Overview

Problem

Ejection systems face challenges in safely expelling occupants of varying weights from aircraft across different speed regimes, altitudes, and attitudes, as a single thrust force may not be suitable for all weight ranges.

Innovation Solution

A rocket catapult assembly with a motor assembly, first and second cartridges providing different thrusts, and a load cell-controlled ignitor system to select the appropriate thrust based on occupant weight, ensuring optimal ejection force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single thrust force is used for ejection, then the system is simple, but it cannot safely eject occupants of varying weights

Engineering Contradiction:

Improveadaptability to varying occupant weightsVSAvoidcomplexity of thrust selection system

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The propulsion system is segmented into multiple independent cartridges (first cartridge, second cartridge) with different thrust levels. Each cartridge can be selectively ignited based on occupant weight, allowing the system to provide appropriate thrust for different weight ranges while maintaining a modular and manageable structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically selects which cartridge(s) to ignite based on real-time weight measurement from the load cell. This dynamic adaptation allows the ejection system to optimize performance for each occupant's specific weight, transitioning from a static single-thrust design to a dynamic multi-thrust system.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If a single thrust force is used for ejection, then the system is simple to operate, but it cannot accommodate different weight ranges effectively

Engineering Contradiction:

Improveaccommodation of different weight rangesVSAvoidease of ejection operation

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system performs self-adjustment by automatically measuring occupant weight via the load cell and selecting the appropriate cartridge configuration without pilot intervention. The controller autonomously determines which ignitor(s) to activate based on the measured weight, eliminating the need for manual thrust selection while ensuring optimal ejection performance.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The load cell provides continuous feedback on occupant weight to the controller, which then adjusts the ignition configuration accordingly. This feedback loop ensures the system automatically adapts to different weight ranges, maintaining ease of operation while improving adaptability.

Inventive Principle:

Principle #23Feedback

3Reliability

If maximum thrust is always applied, then heavy occupants are safely ejected, but lightweight occupants experience excessive force

Engineering Contradiction:

Improvesafety of ejection for heavy occupantsVSAvoidexcessive thrust on lightweight occupants

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Different portions of the propulsion system (different cartridges) are designed with different thrust characteristics tailored to specific weight ranges. The first cartridge provides lower thrust for lightweight occupants, while the second cartridge provides higher thrust for heavy occupants, ensuring each occupant type receives appropriate force levels.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system applies partial action by selectively igniting only the necessary cartridge(s) based on occupant weight. For lightweight occupants, only the first cartridge is ignited, providing sufficient thrust without excessive force. For heavy occupants, the second cartridge is ignited to provide the necessary maximum thrust.

Inventive Principle:

Principle #16Partial or excessive action

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 system ensures safe ejection of occupants by adjusting thrust according to weight, accommodating a range of weights from lightweight to heavyweight individuals effectively.

Implementation Method 1

compressing a load cell disposed in a seat pan of the ejection seat

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

enabling or disabling a first ignitor in response to compressing the load cell, wherein the first ignitor is coupled to, and in communication with, a first cartridge of the rocket catapult assembly

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS11434012B2Variable thrust catapult

Publication Date: 2022.09.06 AMI IND INC

AI summary

A rocket catapult assembly for an ejection seat may comprise a motor assembly including a proximal end and a distal end, a first cartridge, and a second cartridge. The first cartridge and the second cartridge may be configured to provide a variable thrust based on an occupant's weight. The first cartridge may provide a thrust corresponding to a relatively light weight occupant, the second cartridge may provide a thrust corresponding to a relatively average weight occupant, and the first cartridge and second cartridge may provide a combined thrust corresponding to a relatively heavy weight occupant.