Cannon Projectile Rocket Fuse With Capacitor-Based Dual-Event Arming
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Solution Overview
Problem
Existing projectiles fired from smoothbore guns face challenges in reliably detecting two distinct events associated with firing, such as rotation acceleration, which is low and unreliable, complicating compliance with military safety standards like NATO Stanag No. 4187, and existing solutions like rotation sensors or pressure/temperature measurements are complex and costly.
Innovation Solution
A fuse system for projectiles that includes a capacitor connected to an electrical igniter, charging upon propellant ignition, and an inertial sensor, requiring detection of both propellant ignition and firing acceleration to arm the fuse, ensuring safety by lifting two distinct safeties without additional mechanical locks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotation sensors or pressure/temperature measurement devices are used to detect firing events, then safety standards can be met, but device complexity and cost increase
Solution Approach 1:
The capacitor serves multiple functions: it is part of the electrical ignition circuit for the propellant charge and simultaneously serves as a detection element for the first firing event. When the igniter discharges to ignite the propellant, the capacitor's charge state provides detection information to the computer, eliminating the need for separate detection sensors.
Solution Approach 2:
The existing electrical ignition components (capacitor and igniter) perform their primary function of igniting the propellant while also providing the detection function for the first firing event. The system uses its own operational parameters (capacitor charge state during ignition) to detect the firing event, avoiding additional hardware.
2Measurement precision
If magnetic rotation sensors are installed to count projectile rotations, then firing events can be detected, but the fuse definition becomes complicated
Solution Approach 1:
The capacitor in the electrical ignition circuit serves dual purposes: providing ignition energy to the propellant charge and simultaneously serving as a detection element for the first firing event. The computer monitors the capacitor's charge state during the ignition process to detect when firing occurs, eliminating the need for separate rotation sensors or magnetic detection devices.
3Reliability
If pistons are used to detect gas pressure in the weapon chamber, then firing can be detected, but leaks between projectile and weapon chamber occur
Solution Approach 1:
The invention extracts the detection function from the physical gas pressure measurement mechanism (pistons that required penetrating the projectile structure) and relocates it to the electrical domain. The capacitor's electrical charge state during ignition provides firing detection without requiring physical penetration or gas pressure measurement, thereby eliminating gas leaks.
4Device complexity
If a single capacitor is used for both ignition energy and safety detection, then system simplicity is achieved, but compliance with military safety standards is compromised
Solution Approach 1:
The computer continuously monitors the capacitor's charge state during the ignition process and uses this feedback information to detect the first firing event. This feedback mechanism allows the same capacitor to serve both ignition and detection functions while maintaining compliance with safety standards that require reliable detection of firing events.
Solution Approach 2:
The invention replaces mechanical or physical detection systems (rotation sensors, pressure pistons, temperature sensors) with an electrical detection system based on monitoring the capacitor's charge state. This substitution maintains system simplicity while achieving reliable firing event detection that complies with military safety standards.
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
Meets high safety standards by reliably detecting two firing events, ensuring safe arming without complex sensors or leaks, and is cost-effective, suitable for smoothbore guns.
Implementation Method 1
said fuse comprises a capacitor (20) which is intended to be connected to the electrical ignition means of the propellant charge and which charges when said propellant charge is ignited
Implementation Method 2
an inertial sensor which is connected to the computer and which constitutes a second firing safety
Data Source
Figure 1~2
Figure 3
AI summary
The aim of the invention is a rocket (11) for a projectile intended to be fired by a cannon by lighting a propelling charge using an electric ignitor (6). This rocket (11) can transition from a safety position to an armed position post-firing by removing at least two different safeties. This rocket (11) is characterised in that it comprises a capacitor (20) that is intended to be connected to the electric ignitor (6) and that charges when the propelling charge is ignited, and also a computer (18) that detects the charge of the capacitor (20) to allow the rocket (11) to be armed when this charge is above or equal to a reference value, with the charge of the capacitor (20) constituting a first firing safety.