SA4 Flashcards
What are the four types of natural fibres?
Cellulose, Silk, Wool and Rubber
What are the two main types of plastics and their differences?
Thermoplastics soften on heating and can be reshaped and re-harden on cooling.
Thermosetting plastic is incapable of being softened by heat.
What is used for non permanent seals?
Luting
What are the two main types of defects?
Mechanical and Chemical
Name three types of corrosion
Rust (Ferrous Oxide)
Aluminium oxidation
Mazak contamination
Cupric Azide
Zinc Exudation
What is the definition of corrosion?
Conversion of a metal to a non-metallic state
When are stressors most likely to be formed in metal and what can aggravate them?
Stresses may be formed during manufacture and can be aggravated by environment changes
Define seasonal cracking?
Stressed areas of metals cracking due to ammonia forming cuprammonium during hot and cold changes
What are the four main types of shell filling techniques?
Casting, pressing, extruding, preforming/cocooning
What are disadvantages of hot/melt filling?
Shrinkage, dusting and cracking
What are three methods of casting explosives fillings?
Liquid and biscuits, straight pour and creamed
What compounds can be used to coat the internal shell wall?
Shellac, varnish, bitumen. lacquer, resin
What is dark ignition?
Prevent the firer being dazzled, prevent the enemy seeing the gun location
What are the purposes of tracers
Emit light, may be used as a self destruct
Principle requirements of tracers
Luminosity, strength, consistency of performance, ease of ignition
What are the two means of ignition and explain them
Direct ignition - A cap sets back into an anvil to initiate the igniter composition
Propellant ignition- Ignited by hot propellant gases
What are the three types of tracers?
Tracer projectile, tracer and igniter projectile, Integral tracer
Name the two types of primers
Percussion and electric
Name types of obturating systems
Cap holder, ball in cone seating, cone in cone seating, firing plug
What are the components of a conducting cap?
Base, pole, unit, plug, magazine
