Fuzing Lesson 13

3 Components of a Warhead? Fuze Explosive Fill Warhead Case

Introduction What is a fuze? Devise designed to detonate, or set forces into action to ignite or detonate the charge under specific conditions What is the difference between fuse and fuze? Fuse – simple pyrotechnic Fuze – more complicated device

Functions of the Fuze Keep weapon safe Arm weapon Recognize or detect target Initiate detonation

Basic Fuzing System Safing Warhead Warhead TDD And (sensor) Arming Target Detecting Device TDD (sensor) Warhead Safing And Arming Device Warhead Explosive Output Lead Detonator Detonator Target Detecting Device Saving and Arming Device

Fuzing Catagorization Fuzes catagorized by the manner of fuze operation i.e. by target sensor Fuze Catagories Impact or contact Ambient Timer Proximity

Impact Fuze Contact Typical Sensor mechanisms Detects weapon’s first impact with an object Output initiate the detonator Typical Sensor mechanisms Displacing an inertial mass Stressing a piezoelectric crystal Short-circuiting a coaxial transmission line Interrupting an electrical circuit

Impact Fuze Sidewinder Mk-46 Torpedo* Tomahawk Harpoon

Ambient Fuze Senses particular environment Depth charges Air pressure Mark XI

Timer/Delay Fuze Preset time elapse a timing devise will send a fire signal to the detonator Mechanical, electronic, igniferous, or chemical Can be combined with impact fuze….

Proximity Fuze Most complex class of fuze Developed by US and England early in WWII…why? Called Variable Time (VT) to mask their true nature Can be Active, Semi-active, or passive Electromagnetic – range gates Magnetostatic – presence of magnetic flux Acoustic – acoustic distrubances Seismic – similar to acoustic, however lower bandwidth and extremely sensitive

Proximity Fuzes Active Semi-Active Passive

Safing & Arming Mechanism Safety & Arming Sensor: Barrier between the TDD and the warhead Isolate detonator from the booster Warhead Target Detecting Device TDD (sensor) Missiles arm after being accelerated for a certain amount of time. Safing And Arming Device Explosive Output Lead Detonator

Activation Forces Used to arm the warhead Time Acceleration (Setback) Deceleration (Creep) Centrifugal Impact Time – timer, can be variable or mechanical Example – 5” round: HE-VT or HE-MT Acceleration – fuse contacts get set back into the warhead by the acceleration of the weapon SM-2 Decleration – used for burrowing into the target Harpoon Centrifugal – arming, the rotational force of the warhead arms it. BLU-97 submunitions – rotational motion as it travels to the ground Impact – Gotta hit the thing. GBU’s

Redundancy in Fuze System Safety - Devices placed in series in firing path for safety. Reliability - Components placed in parallel in firing path for arming & firing reliability.

Redundancy in Fuze System Safety and Arming devices arranged in series for safety Detonators and Target Sensors arranged in parallel for reliability A B System S F

Questions?