Explosives & Propellants Flashcards
What is ASA composition made up of and what %?
Lead azide 68%
Lead styphnate 29%
Aluminium powder 3%
What are the two types of explosive initiators?
Detonators
Ignitors
Primary/initiatory definition?
Substance or mixture of substances used to initiate a detonation or a burning reaction.
5 Primary explosive characteristics?
Stability over long storage periods Optimum sensitivity to applied stimulus Optimum output of the required kind Compatibility with materials Safety in loading and handling
3 Means of initiation?
Heat
Shock
Friction
2 explosive initiators?
Detonators
Ignitors
7 initiators types?
- Conducting composition igniters and detonators
- hot bridge wire igniters and detonators
- exploding bridge wire detonators
- Pyrotechnic igniters
- percussion igniters
- stab igniters and detonators
- flash receptive detonators
6 Primary explosive compounds?
Lead azide Lead styphnate Lead dinitro rescorcinate PETN Von Herz mixture ASA compound
What is the abbreviation for composition explosives?
CE
Is the dust or explosive residue hazardous to health?
Yes
Propellants are classed as low explosive name two others?
Gunpowder
Pyrotechnics
HE definition?
Any explosive which once initiated decomposes almost instantaneously into its original molecular structure by the passage of a detonation wave through it, with a subsequent production of heat and gases and the liberation of great energy.
Detonation definition?
An extremely rapid chemical change with the evolution of heat and gas, accompanied by a violent disruptive effect and intense blast.
LE definition?
An explosive substance, which decomposes rapidly through combustion with the evolution of heat and flash and generates a large quantity of gaseous products burning up to 300m/s
10 types of main HE?
CE - Tetryal TR1 - tetryl replacement 1 TNT - trinitrotoluene RDX - cyclotrimethylenetrinitromine PETN - pentaerythritol tetranitrate Picric Acid - trinitrophenol COMP B - composition B PE4 - plastic explosive No. 4 C4 - composition 4 HMX - cylotetramethylenetranitramine
What is the purpose of additives used in HE?
When added to a basic material or a mixture, confers on it the required degree of sensitivity to shock or friction.
5 purposes of additives used in HE?
Increase sensitivity Decrease sensitivity Improve stability Improve mouldability Increase blast effects
How many and what types of desenitizers are used in HE?
3
Wax
aluminium
TNT
What are the 4 advantages of adding aluminium to HE?
- Takes no part in the initial stages of detention
- absorbs energy and lessons the release
- reinforcing action due to exothermic (produces heat and energy) interaction with some gaseous products of explosion
- increases blast effect
Sensitivity definition?
Sensitivity is the property which all explosives possess of being brought to functioning by blow or friction
Figure of insensitivity ( F of I )?
Used to indicate if an explosive is safe to store, transport and use
4 main types of phlegmatizing?
Wax
Oil
Alcohol
Water
Phlegmatizing mean?
A term applied to an explosive that has had an agent added to stabilize or desensitize it.
Purpose of sensitisers?
When added to a basic material or a mixture, confers on it the required degree of sensitivity to shock or friction
2 factors effecting sensitivity?
Increased with temperature
Requirement of sensitisers
- most explosives require to be desensitised for use in most Ammunition
Wax is a desensitiser, it increases insensitivity by?
Lowering the figure of power ( F of P )
And
The velocity of detonation ( V of D )
Explosives can be desensitised by adding less sensitive explosives name 1?
TNT
Aluminium is used in what 5 ?
Mines Grenades Aircraft bombs Torpedos Anti armour projectiles
Disadvantages of aluminium?
Very hygroscopic
Gives off hydrogen gas
Can build up gas in the item
Tendency to settle out of explosive
Settling out of additives in explosives can be overcome by adding what 2?
Carbon black
Lecithin
4 types of plasticisers?
Non energetic
Energetic
Non reactive
Reactive
Plasticisers improve what?
Suitability for use of some explosives as fillings or provide mouldability for specialised use
Improves flexibility, especially at low temperatures
What are the 2 types of taggants?
Detection taggants
Identification taggants
Propellant definition?
An explosive which by controlled burning provides the gas pressure required to give motion to a projectile or missile
Main ingredient in single based propellant?
NC
4 Advantages of double based propellant?
Higher energy rating
Easily ignited
Higher flame temperature
Higher burn rate
8 additives used in propellant?
Coolant Stabiliser Plasticiser Moderant Flash inhibitor Decoppering agent Antiwear additive Surface lubricants
9 properties of idle propellant?
- Acceptable high energy/bulk ratio
- Predictable burning rate over a wide range of pressures
- acceptably low flame temperature
- capability of being easily and rapidly ignited
- Acceptably low sensitiveness to all other possible causes of initiation
- cheap, easy, and rapid manufacture and blending
- long shelf life under environmental conditions
- minimum tendency to produce flash or smoke
- minimum tendency to produce toxic fumes
Together with calorimetric value and rate of burning what determines the rate of gas evolution during burning?
The size and shape of the propellant
Pioneers law rate equals what?
Burning coefficient X pressure to the power of pressure index
2 categories of propellant?
Liquid
Solid
2 types of liquid propellant?
Mono propellant
Bi propellant
Solid propellant can be divided into 2 types?
Colloidal
- single
- double
- and triple based
Composite
Single based propellant is made up of what?
NC
Single based propellant advantages (3)?
- Cooler burning
- Generates less flash then cordite
- Ballistics less effected by change in charge temperature
3 Single based propellant uses?
SAA propellants including heavy MG’s
Secondary charges for mortars
Igniters
What does double base propellants consist of?
NC
NG
5 Single based propellant disadvantages?
- more hygroscopic
- not easy to ignite
- less powerful then cordite
- liable to give sporadic high pressure if ignition is defective
- too brittle to use in cord form
4 Double based propellant advantages?
Easily ignited
Higher energy rating then single based
Higher flame temperature
Higher burning rate
3 double based propellant disadvantages?
Can cause excessive weapon erosion
More dangerous to manufacture
More costly to manufacture
3 Double propellant uses?
- In cordites
- In the form of ballistite for primary cartridges in mortars
- for small arms cartridges where high bulk energies are required
Triple based propellants consist of?
NC
NG
NQ or picrite
3 Triple based propellants properties?
- Normally cooler then double based propellants
- normally have lower bulk energies than double based propellants
- more difficult to ignite
Triple based propellants uses?
In charges for arty pieces and tank guns
2 decoppering agents?
Tin
Lead
3 ways to control the burn rate?
Propellant composition
Shape of propellant
Size of propellant
3 types of burning rates?
Degressive
Neutral burning
Progressive burning
Degressive burning shapes?
Cord
Flake
Strip/ribbon
What is degressive burning?
Total surface area decreases as the propellant burns
What is neutral burning?
External surface decreases at the same rate that internal surface increases during burning
Neutral burning shapes?
Tubular
Cogged
Star centre
What is progressive burning?
Total surface area increases during burning?
Progressive burning shapes?
Rosette
Multi tubular
What is the 3 Roles of illuminating compositions?
- to provide a steady source of light to illuminate targets for visual or photographic reconnaissance purposes
- to provide coloured signals which are identifiable against difficult backgrounds at considerable distances
- to provide fillings suitable for use as tracers in SAA and other direct fire ammunition
4 design requirements for illuminating compositions?
- it must burn for the required time
- must have the appropriate luminosity
- withstand firing forces ie. tracer
- the colour of the flame must be correct and as saturated as possible
2 purposes of dark ignition?
- to avoid observation by the enemy of the exact location of the weapon
- to avoid dazzling the gun layers at night when fired from multiple or automatic weapons
What is the role of the signal composition?
To transmit concise messages through the atmosphere over considerable distances
2 types of signal composition?
- those which produce a light of distinctive colour
- those which produce coloured smoke
4 design requirements for the tracer composition?
Luminosity
Strength
Consistency of performance
Ease of ignition
3 chemical constituents?
Fuel - magnesium
Oxidant- oxygen supply
Binder - to ensure correct burn time
Red colour is produced by?
Strontium nitrate
Yellow colour produced by?
Sodium nitrate
Green produced by?
Barium nitrate
Blue produced by?
Copper carbonate
White produced by?
Barium nitrate/potassium nitrate mixture
Orange produced by?
Calcium nitrate
Role of tracer?
Tracer compositions are signal compositions used in projectiles of all nature’s to indicate the trajectory of that Projectile
Define igniter composition?
Mainly used for propellant or pyrotechnics systems. They produce hot flames, usually accompanied by sparks and hot gases, for relatively short times.
Define incendiary composition?
Incendiary compositions produce hot flames and a large evolution of heat, together with molten iron when thermite type mixtures are used
Delay compositions are used for what?
To produce a time interval between two igniting or explosive events
2 distinct groups incendiary materials fall into?
Metals and alloys
Combustible fluids
2 metal most used as incendiary agents?
Aluminium
Magnesium
5 natures that contain incendiary compositions?
Grenades Cannon SAA Aircraft bombs Preset charges
3 types of flame and heat producing compositions?
Igniter compositions
Priming compositions
Incendiary compositions
AS developed propellants are allocated a number which relates to its physical form and its chemical composition what do they mean?
Physical shape
Deterrent coating
2 digit number indicating single or double base and specific propellant type
Define a pyrotechnic?
A pyrotechnic is a chemical or mixture of chemicals which when ignited burn at a controlled rate liberating energy and reactive products which can be converted into the desired effect
4 main categories of special effects produced by pyrotechnics?
Heat
Light
Smoke
Sound
8 pyrotechnic groups?
Illuminating compositions Smoke compositions Signal compositions Delay compositions Tracer compositions Incendiary compositions Priming compositions Simulators Pyromechanisms
Role of the first fire composition?
Acts as the booster between the low energy out put of the initiator and the main composition which may be difficult to ignite
WW1 led to a demand for military type pyrotechnics for use as? (4)
Incendiary
Smoke
Illumination
Signals
Illuminating compositions mainly based on?
Magnesium or aluminium with nitrates as oxidants
Incendiary compositions two basic groups?
Spontaneously burning metals
Combustible fluids
Priming compositions should be?
Easily ignited
Generate high heat
Not burn too quickly or violently
Be compatible with the mixture used
Priming compositions contain?
Potassium nitrate
Powdered silicon
Sulphurless medaled gunpowder
Pyromechanism group covers?
Mechanical actuators
Gas generators
Explosive separators
Main fuel used in pyrotechnics?
7 metals
5 non metals
Metals Aluminium Chromium Iron Magnesium Titanium Tungsten Zirconium
Non metals Boron Silicon Carbon sulphur Phosphorus
Pyrotechnic oxidising agents? (7)
Chlorates Chromates/dichromates Halocarbons Iodates Nitrates Oxides Perchlorates
Pyrotechnic binders?
Paraffin wax Beeswax Catalina wax Chinese wax Boiled linseed oil Lithographic varnish Shellac
Bakelite resin Polyester resin Chlorinated rubber Polyvinyl chloride Thoikol rubber Epoxy resin
Caps, igniters and detonators may be ignited or initiated by what ways?
Mechanical means
-percussion/friction
Electrical means
- bridge wire
Sparking/igniferous
- explosive is receptive to flame and spark
Cap (primer) composition mixtures comprise three essential ingredients?
The primary explosive
The sensitiser
The oxidiser
There are two types of initiators being used?
Igniferous
Disruptive
Caps/primer metals must have what 3 qualities?
- Expand easily to provide obturation
- Strong enough to withstand striker blow
- Contain the explosion of the composition
Caps used in what 4 natures?
Mortars SAA Arty cartridge cases Grenades Pyrotechnic compositions
Main two types of smoke compositions?
- zinc powder and zinc oxide with carbon tetrachloride absorbed on kieselguhr or magnesium carbonate
- zinc oxide, zinc powder and hexachlorethane
Military service has two main requirements for two distinct types of smoke producing munitions?
Screening smoke
Signalling smoke
The simplest form of pyrotechnic smoke is produced by burning WP in air to form phosphorus pentoxide true or false?
True
3 main types of EO which has a filling of WP as a screening smoke?
Grenades
Mortar bombs
Artillery projectiles
Smoke compositions are required for two main purposes?
Tactical screening smoke
Signalling smoke
5 Ideal properties of smoke?
- Immediate in effect
- Unaffected as far as possible by climate/ weather
- persistent
- non anti personnel
- non incendiary
2 types of screening smoke?
Tactical smoke
Defensive smoke
Tactical smoke should what 3?
- Denies the enemy observation of troops or installations
- produced for long periods and not be greatly affected by climate or weather
- no requirement for screen to build up rapidly but screen should remain close to ground
Defensive smoke should what 3?
- used to hide our troops in a emergency situation
- screen build up very rapidly
- without harassing personnel nor a fire risk
2 screening smoke agents?
WP
Berger compositions
3 Advantages of WP?
Immediate effect on burning
Excellent screen produced
No priming or ignition devices required
6 Disadvantages of WP?
- Pillaging effect on burning
- Severe burns
- Harassing effect on eyes,nose and throat
- fire risk
- expensive method of filling
- isolation in storage and transportation
Explosion definition?
An explosion is the violent and rapid decomposition of energetic material to produce energy (heat) and gas which will lead to violent pressure rupturing any confining structure
Explosive definition?
An explosive is a substance manufactured with a view to producing an explosion or pyrotechnic effect. An explosive atmosphere of gas vapour or dust is not considered to be an explosive
Deflagration definition?
Is a technical term describing subsonic combustion that usually propagates through thermal conductivity
Detonation definition?
Involves a supersonic exothermic front accelerating through a medium that drives a shock front propagating directly in front of it
