Summative 1 - Explosives and propellants Flashcards
Define an initiator/primary explosive?
A substance, or mixture of substances used to initiate a detonation or a burning reaction.
List the required characteristics of an initiator/primary explosive?
- Stability over long storage periods
- Optimum sensitivity to applied stimulus
- Optimum output of the required kind
- Compatibility with materials
- Safety in loading and handling
What are the two types of explosive initiators?
Detonators and Igniters
List the types of explosive initiators
- Flash receptive detonators
- stab igniters and detonators
- percussion igniters
- conduction composition igniters and detonators
- hot bridge wire igniters and detonators
- Exploding bridge wire detonators
- Pyrotechnic igniters
Primary explosive compounds include?
Lead Azide Lead Styphnate Lead Dinitro resorcinate PETN Von Herz Mixtures ASA compound
List characteristics of Lead Azide?
- F of I: 15 -20
- Good shelf life
- unstable in presence of moisture, oxidising agents and ammonia
- More sensitive to friction than impact
- Used in conjunction with aluminium or Lead styphnate
Characteristics of lead styphnate?
- F of I = 12
- Sensitive to discharge of static electricity
- easily ignited by flame
- stable at room and elevated temperature
- used in conjunction with aluminium and lead azide(ASA)
Characteristics of Lead Dinitro Resorcinate?
- Weak initiator
- High sensitivity to friction or stab
- less sensitive to impact
- used in priming composition and electrical igniters
- Found in primers
Characteristics of PETN
- F of I = 50
- Sensitive to impact
- used in conjunction with TNT (Pentolite)
- Classified as a secondary explosive
Explain Characteristics of Von Herz mixtures
- Proposed due to the removal of Mercury Fulminate due to toxicity
- Replaced by Lead styphnate
Composition and Characteristics of ASA, and its in-service uses?
- F2 detonator (an ASA detonator) consists of:
- Lead azide at 68%
- Lead Styphnate at 29%
- Aluminium powder at 3%
- Used in military detonators
- Excellent initiator of CE/Det cord
What is the F of I range of primary explosives?
and is lower or higher more sensitive?
F of I of 1-50
Det cord at 50 is a secondary explosive
Lower is more sensitive.
Definition of a high explosive?
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.
Definition of detonation?
An extremely rapid chemical change with the
evolution of heat and gas, accompanied by a
violent disruptive effect and intense blast.
Definition of low explosive?
An explosive substance, which decomposes rapidly through combustion with the evolution of heat and flash, and generates a large quantity of gaseous products.
Burning rate up to 300m/s.
Main difference between HE and low explosive?
Whether or not the speed (velocity of detonation in m/s) of decomposition is greater than the speed of sound (supersonic) in that material.
Speak to the detonation/ignition of low explosives?
- Rate of decomposition is slower than the speed of sound
- decomposition is propagated by a flame front, which travels slower than a supersonic shock wave (HE).
- Depending on degree of confinement, it is possible for low explosive deflagrate very quickly, producing an effect similar to detonation.
Speak to the detonation for HE?
- HEs are explosive materials where the speed of decomposition is greater than the speed of sound, resulting in a detonation rather then deflagration
- The explosive shock front passes through the material at supersonic speed
- speed results in a greater release of energy compared to low explosives
- speed of propagation normally referred to in m/s, military HE often in excess of 7000m/s
What are common uses of the Low Explosive, Gunpowder?
Used extensively in igniters, primers, tubes, fuzes, blank charges, FBT, ejection charges in carrier projectiles and even as a demolition (quarrying) explosive to break rock.
Low explosives: List some propellants and its benefit/characteristics.
- Gunpowder, smokeless, solid or liquid.
- regularity of burning produces a moderately high and sustained gas pressure in a bore or rocket motor, thereby steadily applying acceleration to a projectile.
Low explosives: List uses and characteristics of pyrotechnics
- Low explosive stores generally containing combustible materials
- used for smoke screens, signalling or illumination, and BMS
- Can break a container if sufficiently confined, however will not lead to a supersonic shockwave.
List main types of Low explosive?
Gunpowder
Propellants
pyrotechnics
List types of high explosives?
- Composite explosive (CE) - Tetryl
- Tetryl replacement 1 (TR1)
- Trinitrotoluene- TNT
- RDX
- PETN
- Picric Acid
- Composition B (COMB B)
- Plastic explosive No.4 (PE4)
- Composition 4 - C4
- HMX
List characteristics of Composite Explosive (CE) Tetryl?
An intermediary high explosives which is used to boost less sensitive explosives
The US term is Tetryl
CE has been replaced by TR1
VoD - 7500 m/s
List characteristics of Tetryl Replacement 1 (TR1)?
Normally used as an intermediary to boost less sensitive explosives
RDX 98.75% & polyethylene wax 1.25%
Introduced into service as a composition explosive (CE) Tetryl
List characteristics of Trinitrotoluene -TNT?
Good all round HE
Usually combined with RDX or CE.
Figure of Insensitivity 150.
VoD - 6950 m/s
List characteristics of RDX?
Relatively insensitive to a blow or friction
Figure of Insensitivity 80
Common filling for projectiles
Used in the manufacture of Plastic Explosives where gelatin and plasticisers are added.
VoD - 8450 m/s
List characteristics of PETN
High Explosive used as an intermediary explosive
Comes in powder form and currently used in det cord
Slightly more sensitive than RDX but with similar properties.
VoD - 8300 m/s
List characteristics of Picric Acid?
Discovered by Auguste Laurent in 1841
First used as a yellow dye. Has also been used as an antiseptic
French used it as a projectile filling about 1885 and later by the British until superseded by TNT during WW1.
The Japanese used it extensively during WW2 as projectile filling and the Germans to a lesser extent.
Very acidic explosive which gave rise to the formation of sensitive crystal salts as the explosive aged
Was used for the manufacture of Explosive D (Dunnite), that formed the main fill in some armour piercing projectiles.
VoD - 6800 m/s
List characteristics of Composition B (COMP B)
RDX 59.5% / TNT 39.5% / Wax 1%
Primarily used in military ammunition for Demolition Charges, Mines, Projectile fillings and Depth Charges
Most common type used in Australian HE Ammunition.
VoD - 7800 m/s
List characteristics of plastic explosive No.4 (PE4)
RDX 88% / Plasticiser and other ingredients 12%
HE with a high V of D.
Developed so that explosive could be brought into intimate contact with the surface under attack.
Has a consistency of putty and may be molded into any shape
VoD - 8200 m/s
List characteristics of Composition 4 (C4)?
RDX 91% / Plasticisers and other ingredients 9%
Similar properties to PE4
Used by US military as their primary plastic explosive.
VoD - 7500 m/s
List Characteristics of HMX?
Derivative of RDX
About 4 times the cost of RDX / More powerful HE
Special purposes such as main filling for Rocket Warheads
Not in artillery projectiles due to its sensitivity to impact or friction.
VoD - 9120 m/s
What are explosives mixed with HMX called? list an example.
HMX combined with other explosives are known as OCTOLS:
HMX 70% / TNT 30% is known as OCTOL
Warhead filling for Rocket 66mm HEAT M72.
VoD - 9120 m/s
What did studies into insensitive munitions lead to?
Resulted in a range of Polymer Bonded Explosives (PBXs) which still provide the energetic effect required while drastically reducing the chance of sympathetic detonation of adjacent munitions
List Hazards associated with LE/HE
Dust affecting the lungs
Absorption can occur whilst handling NG based explosives causing severe headaches (AN60 Gelignite)
Breaching of fumes after a demolition can cause headaches
Overexposure can cause cyanosis and even sudden death.
Dust from explosives can also cause problems with the digestive system.
Most problems with explosives occur
through prolonged exposure or misuse of
the explosive.
CE (Tetryl) has produced severe dermatitis, which
is one of the reasons that it has now been
replaced by TR1 explosive (98.75% RDX
and 1.25% Wax).
Dangerous compounds may be formed by
the reaction of explosives with the metal
container in which they are stored e.g. Picric
List hazards associated to PETN?
Not considered to be dangerous by the inhalation of small amounts because of its low solubility of the compound
A 64mg oral dose in an adult male produced no ill effects.
It has poor penetration through the skin.
Some cases of dermatitis have occurred.
List Hazards associated with RDX?
High melting point and is not very volatile
Inhalation of RDX vapour would therefore not be expected to pose problems under normal circumstances.
Using RDX based explosives (PE4/C4) as a fuel to cook is not a normal circumstance.
Reported cases of dermatitis appears to have been caused by impurities within the PE4/C4 instead of RDX.
List hazards associated with service EO?
Usually issued wrapped or protected.
Pose no serious threat if not abused/misused.
Hygiene, especially washing of hands after handling
explosives, is important.
Using explosives in well ventilated areas should be
always observed.
Remember that data supplied is not by any means
exhaustive, so even though a hazard my not have been identified, good hygiene practices reduce the chance of an adverse effect.
Definition of a propellant?
An explosive which, by controlled burning,
provides the gas pressure required to give
motion to a projectile or missile.
List the ideal properties of a propellant
An acceptable High Energy/Bulk ratio
A predictable burning rate over a wide range of pressures
An acceptably low flame temperature
A capability of being easily and rapidly ignited
An acceptably low sensitiveness to all other possible causes of initiation
Cheap, easy and rapid manufacture and blending.
A long shelf-life under all environmental conditions
A minimum tendancy to produce flash or smoke
A minimum tendency to produce toxic fumes.
List factors affecting propellant performance.
- Calorimetric value
- Density
- Burning rate and pressure
- Shape and size
- Pioberts Law
- Vielle’s equation
What is calorimetric value?
- the quantity of heat evolved when the propellant is burnt without added oxygen measured in Cal/g.
- The calorimetric value depends only on the chemical composition of the propellant.
What is Density, in regards to propellant performance, and why is it important?
Where volume is a limiting factor, density is an important property of a propellant.
The limited space inside a tank requires a high density propellant, which saves valuable turret space.
Why is burning rate and pressure important in propellant performance?
- The rate of burning effects the surrounding pressure.
- Generally the rate of burning increases with a rise in pressure.
Why is shape and size important for propellant performance?
Together with the calorimetric value and rate of burning, the shape and size of the propellant determines the rate of gas evolution during burning.
What are the two categories of propellant?
Liquid and solid
List the liquid propellant and their characteristics
Monopropellant
- -Single component substance
- -Generally ignited by electric means.
Bi Propellant: -- Fuel and Oxidiser. -- Injected into combustion chamber. -- Ignited by own reaction (hypergolic) or ignition system (non hypergolic).
List the two types of solid propellant.
- Colloidal: Single, Double, Triple Based
- Composite
What is a colloid and its meaning?
The word colloid is derived from the Greek
‘kolla’ meaning glue
It involves the dissolving of the main
ingredient in a geletinised state to form a
colloid.
What is Vieelle’s equation?
r = β x Ρ^a
r = rate of burning β= burning rate coefficient Ρ= Pressure α= Pressure index (0.9 for most gun propellants)
Explain the difference between a high mass burning rate, and a low mass burning rate.
A high mass burning rate will have a larger peak of pressure sooner, and fall away soon.
In contrast to a low mass burning rate, that will peak later, and slower, and fall away slower.
What are all service propellants currently based on?
NC - Nitrocellulose
How is NC manafacured?
Cellulose:
Uses plant cell material, derived from cotton or
wood.
Nitration of Cellulose:
Steeping of cotton/wood in Nitric and Sulphuric
Acid.
What are the characteristics of raw NC?
- Creamy white fibers.
- Porous & hygroscopic.
- Burns quickly and efficiently.
- Extremely erosive to weapon systems.
- Dry NC is sensitive to spark, impact and
friction.
What are disadvantages of Pure NC?
- Cannot be used as a propellant on its own.
- Burns far too quickly
- Inherently unstable due to acid retention
- Breaks down over time, resulting in increased sensitivity
- Increased sensitivity can lead to spontaneous combustion
An increase in what element in nitrocellulose increases is power? what other effect does it have?
Nitrogen, also increasing decreasing its stability.
What is Nitrocglycerine?
NG: Glycerol Trinitrate or Nitroglycerine, is obtained by the reaction between glycerine and a mixture of nitric and sulphuric acids.
Properties of nitroglycerine?
- Colourless oily Liquid, smells of almonds.
- Very sensitive to impact & friction.
- Burns with a green flame.
- Soluble in acetone and alcohol.
- Will dissolve nitrocellulose of ‘low’ N content.
- Poisonous handling can cause severe
headaches (nitro head).
What are the uses of NG?
Mixed with diatomaceous earth:
- DYNAMITE
Mixed with a plasticiser:
- Nobel’s 808 (early form of plastic explosive, used
by special operations in WW2).
Mixed with certain NC:
- Blasting Gelatine.
An Ingredient of double base propellant.
List Single base propellants characteristics
- Single base propellants consist largely of NC 12.6-13.4% N
- Manufacture process largely designed to plasticise the NC
- dissolved in alcohol, a gelatinised NC produces a dough like substance, which can be extruded.
What are the advantages of Single based propellants?
What are the disadvantages?
ADV:
- Cooler burning, therefore less erosive.
- Generates considerably less flash than cordite.
- Ballistics less effected by change in charge
temperature.
DIS:
- Generally more hygroscopic, therefore more
subject to ballistic change from atmospheric
conditions.
- Not easy to ignite.
- Less powerful than cordite.
- Liable to give sporadic high pressure if ignition is
defective.
- Too brittle to use in cord form.
In what applications are single based propellants used?
- Small Arms propellants, including heavy
machine guns. - Secondary charges for mortars.
- Igniters.
What are the characteristics of double base propellants?
- Double base propellants consist basically of
NC gelatinised with NG. - The NG content normally lies between 30%
and 60%, depending on the type of propellant. - Nitroglycerine is a gelatiniser which dissolves
nitro cellulose, breaking down its fibres and
converting it into a homogeneous colloid.
What are the advantages and disadvantages of double base propellants?
Advantages:
- Easily ignited.
- Higher energy rating than single base.
- Higher flame temperature.
- Higher burning rate.
Disadvantages:
- Can cause excessive weapon erosion.
- More dangerous to manufacture.
- More costly to manufacture.
What are the advantages and disadvantages of double base propellants?
Advantages:
- Easily ignited.
- Higher energy rating than single base.
- Higher flame temperature.
- Higher burning rate.
Disadvantages:
- Can cause excessive weapon erosion.
- More dangerous to manufacture.
- More costly to manufacture.
What are some common uses of double base propellants?
- In cordites
- In the form of ballistite for primary cartridges
in mortars. - For small arms cartridges where high bulk
energies are required.
What are the characteristics of triple based propellants?
- Heterogeneous in nature.
- They consist essentially of a gel of NC and
NG, in which nitroguanidine (picrite) is
suspended in fine particulate form. - The picrite content of these propellants
normally lies between 40% and 55%.
What are the properties of a triple base propellant?
- Triple based propellants are normally cooler than double-based propellants: therefore muzzle flash is reduced
- Triple-based propellants normally have lower bulk energies than double-based propellants
- They are more difficult to ignite
What common military use for a triple base propellant?
Charges for tank and artillery rounds
What are composite propellants?
- Composite propellants or high energy
propellants, have been manufactured due to
the difficulty in manufacturing double base
rocket and rocket motor propellants in large
grains. - Composite propellants do not contain NC,
but are a physical mixture of fuel and
oxidant, with binders.
List eight additives of propellants
Stabilisers
Plasticisers
Coolants
Surface moderants
Surface lubricants
Flash inhibitors
De-coppering agents
Anti wear additives
What are three ways of controlling burn rate?
Propellant composition.
Shape of propellant.
Size of propellant.
What are the three burning rates?
Degressive burning.
Neutral burning (constant burning).
Progressive burning.
Explain degressive burning, its applications, and list three shapes which help cause it.
- Total surface area decreases as the
propellant burns. - Evolution of gases is greater at first and then
falls during burning.
Uses:
- SAA
- Mortar
- RKT Boost Motors
Shapes - Cord, Flake, Strip/Ribbon
Explain Neutral burning, its applications, and shapes that help cause it?
- External surface decreases at same rate that internal surface increases during burning. - Evolution of gases constant throughout burning.
- Used in rocket motors.
Shapes: Tubular, cogged, star centre,
Explain Progressive burning, its applications and the shapes that help cause it
- Total surface area increases during
burning. - Evolution of gases increases throughout
burning.
Uses:
- High velocity ammo
- Artillery
- tank
Shapes: Rosette, multi-tubular
Propellant Code (AS) Prefixed AR (Australian Rifle), then 4 numbers denoting what?
First digit: Physical shape
Second digit: Deterrent coating
Third and fourth digits: 2 digit number indicating single or double based and specific propellant type.
Explain at least three of the additives and their functions.
Plasticisers - Increase moldability Stabilisers Sensitisers De-Sensitisers Taggants Aluminium
There are at least 15 propellant shapes, list them, draw at least 6.
Cord Tubular Slotted Tubular Multi Tubular Rosette Strip/Ribbon Flake Scroll Ball Powder Drilled Tube Slotted Groove Tube Star Centred Tube Cruciform Cogged Axial Drilled
What is the role 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.
What are the implementations for illumination composition?
Illuminating shell and mortar bombs.
Cartridges for use with signal pistols.
Flares for photographic purposes.
Trip wire flares.
The tracers or flares in SAA and GW to assist
in observation fire.
What are the design requirements for illum compositions?
Must burn for the correct time.
Must have the correct luminosity.
Withstand firing forces ie . tracer
What are the principal consideration for the development of an illum comp for a specific role?
The rate of burning and the specific intensity.
What are the chemical constituents of illum comps?
Fuel:
Normally magnesium.
Oxidant:
Supplies the oxygen needed for the burning
of the fuel.
– The two main oxidants used are:
Barium nitrate/potassium nitrate mixture for
white light.
– Sodium nitrate for yellow light.
Binding agents:
- Provide cohesion of materials,
- protection for magnesium powder corrosion
- modification of rate of burning
- enhance colour or luminosity of flame,
- modify the sensitivity of the mixture
What are the most common binding materials?
Lithographic varnish
Axaroid resin
polyester resin
thiokol rubber
Calcium oxalate is added to control the rate of burning
What is the role of signal compositions?
To transmit concise messages through the
atmosphere over considerable distances.
Two types:
Those which produce a light of distinctive
colour.
Those which produce coloured smoke.
Design requirements for signalling compositions?
Must burn for the correct time.
Must have the appropriate luminosity.
Measured in candela.
The colour of the flame must be correct “in
hue” (exact colour) and as saturated as
possible.
Chemical constituents of signalling compositions?
Fuel – normally magnesium.
Oxidant - oxygen supply.
Binder – required to ensure correct burn time is achieved.
May also use coloured dyes.
Factors affecting intensity of an illum composition?
The intensity of white light provided by the magnesium is reduced to a minimum by: - Reducing the proportion of magnesium. - Including a carbonaceous fuel such as. - Lactose. - Starch. - Sucrose. - Shellac. - Ivory nut powder.
What are the most used signalling compositions colour producers?
Red:
Strontium nitrate, oxalate.
Yellow:
Sodium nitrate.
Green:
Barium nitrate, chlorate.
Blue:
Copper carbonate, chloride, oxychloride.
White:
Barium nitrate/potassium nitrate mixture.
Orange:
Calcium nitrate.
Explain the use and deployment of decoy flares?
Used to provide a heat signature to counter IR tracking missiles.
Require minimum time from deployment to
maximum temperature.
Usually deployed in pods and can be fired
singly, in series or in bulk.
May also be deployed with chaff flares to
provide radar clutter.
What is the role of tracer compositions?
Tracer compositions are signal compositions
used in projectiles of all natures to indicate the trajectory of that projectile.
What are the design requirements of tracer compositions?
Luminosity:
- Bright enough over distances.
Strength:
-Firm in cavity so flash from propellant does
not consume composition too quickly.
Consistency of performance:
- Must maintain luminosity for determined
period of time.
Ease of ignition:
- Easily ignited by propellant flash.
What are the chemical constituents of tracer compositions?
Combustible agent (fuel): Magnesium.
Oxidant:
Nitrates produce oxygen.
Binding agent:
Beeswax, shellac.
Colour producer:
- Barium nitrate: Green.
- Sodium nitrate: Yellow.
- Strontium nitrate: Red.
What is dark ignition?
Ideally tracers should not be visible by
gunner/firer until projectile travelled approx
100 200m from bore:
- To avoid observation of exact location of
weapon. - To avoid dazzling the gun layers at night
when fired from multiple and automatic
weapons.
What is a dim tracer?
Dim Tracer emits light with a wavelength of 0.7 - 0.8 μm (infrared wavelength) and is visible only by using Night Vision Goggles.
Composition made up of: Barium Peroxide 40%. Strontium Peroxide 40%. Calcium Resinate 10%. Magnesium Carbonate 10%.
What are the three specific groups of flame and heat producing compositions?
Igniter compositions.
Priming compositions.
Incendiary compositions.
Define igniting compositions.
A Pyrotechnic Composition used in propellant
or pyrotechnic systems.
They produce hot flames, usually accompanied by sparks and hot gases, for
relatively short times.
Define a priming composition?
A Pyrotechnic Composition that produces
hot slags, sometimes without the production
of gas.
What three groups that igniters or primers fall into?
Gunpowder of differing fineness.
Organic substances combined with
oxidants (usually potassium or barium
nitrates).
Mixtures that produce slag with little or no gas (metal powders & oxidants).
What are the characteristics of igniters/priming compositions?
Are easily ignited by flame or flash.
Do not burn too quickly or violently.
Generate a large amount of heat.
Be compatible with the mixture with which
they are to be used.
Produce some solids of combustion.
Not be unduly sensitive to impact or shock.
What is delay composition?
What are the two type?
To provide a pyrotechnic delay between two
igniting or explosive events.
All accurate pyrotechnic delays are trains of
composition, which burn in cigarette fashion
from one end to the other.
Types:
Gas producing or gas-less
What are the factors affecting delay compositions?
Chemical nature
Purity
Physical form
Uniformity of blending
Temperature/Pressure
What is an incendiary composition?
A Pyrotechnic Composition which produce hot flames and large evolution of heat.
Can produce molten iron slag when Thermite
mixtures are used.
What are the ideal characteristics of incendiaries?
Should produce hot molten mass or
persistent flame effect.
Heat must not be released or liberated
too quickly.
Difficult to extinguish.
Produce maximum heat from minimum
weight.
What is heat of combustion?
Heat of combustion is the amount of heat
evolved in the combustion of one mol of a
substance with oxygen at constant pressure.
List some typical materials and their heats of combustion?
“Back end of what you want to learn” - Glenn
Aluminium 7000cal/g
Magnesium 6000cal/g
Thermite 790cal/g
Potassium 1240cal/g
Sodium 2170cal/g
Phosphorous 5900cal/g
Carbon Disulphide 3250 cal/g
Turpentine 10830 cal/g
Naphthalene 9168 cal/g
Hydrocarbons Gels (e.g. Napalm) 10000 to 11000 cal/g
List some types of EO that may contain incendiaries.
Types of EO that may contain Incendiaries
are:
Grenades
Cannon projectiles
SAA
Aircraft Bombs
Pre-set Charges
List the two distinct Incendiary materials and their relevant details
Metals and Alloys: - Burn in air with a high heat of combustion and concentrate their heat in a small area. - The two metals most useful: --Aluminium --Magnesium as they have: --High heats of combustion --Low melting points
Combustible fluids:
- Napalm
- Fougasse – blast/incendiary device.
What is useful about white phosphorous?
-Few incendiary materials are spontaneously flammable in air.
What is an example of a jellied incendiary
Jellied incendiaries:
-Aluminium soaps, perspex or rubber
Define a igniting composition?
A Pyrotechnic Composition used in propellant
or pyrotechnic systems.
They produce hot flames, usually
accompanied by sparks and hot gases, for
relatively short times.
What is the definition of a pyrotechnic composition?
A pyrotechnic composition is a chemical, or a
mixture of chemicals which when ignited,
burns at a controlled rate liberating energy and producing a reaction which can be converted into the desired effect.
Most can be considered a material capable of
combustion when correctly initiated to produce a special effect.
What are the pyrotechnic effects?
Heat.
Igniters, incendiaries, delays, metal
producers, heaters.
Light.
Illumination, tracking, signalling and decoy.
Smoke.
Signalling and screening.
Sound.
Signalling and distraction.
List the pyrotechnic groups
Illuminating Compositions.
Smoke Compositions.
Signal Compositions.
Delay Compositions.
Tracer Compositions.
Incendiary Compositions.
Priming Compositions.
Simulators.
Pyromechanisms.
What is the makeup of a pyrotechnic compositions?
The basic pyrotechnic composition consists of intimate mixtures of solid fuels and oxidants together with various additives, to ensure burning at a uniform and predictable rate.
Fuels are necessary to provide combustion
and in some cases, to increase the intensity of the resulting luminosity.
Oxidants provide the oxygen necessary for
combustion of the fuel.
In addition there are binders which improve
cohesion of powdered ingredients.
There are also elements added to protect
metal powders from corrosion, and to reduce
the sensitiveness of compositions to impact
and shock.
List the main fuels for pyro compositions?
Glen: “I would first learn that there are metals and non metals - then learn one or two?”
Metals: Aluminium. Chromium Iron. Magnesium. Titanium. Tungsten. Zirconium.
Non Metals: Boron. Silicon. Carbon. Sulphur Phosphorus.
List some oxidizing agents for pyro compositions.
Chlorates. Chromates / Dichromates (salts). Halocarbons (Halogen/Carbon bond). Iodates.(Iodine bonded by 3 oxygen atoms) Nitrates. Oxides. Perchlorates.
List some binders for pyro compositions?
Natural: Paraffin Wax Beeswax Carauba Wax Chinese Wax Boiled Linseed Oil Lithographic Varnish Shellac
Man Made: Bakelite Resin Polyester Resin Chlorinated rubber Polyvinyl chloride Thoikol Rubber Epoxy Resin
List the 3 properties of pyros
Degradation:
- Susceptible to degradation in storage
- 2/3 contain formulations that contain fine metals particles that are highly reactive
- metals often react with moisture, especially saline solutions.
Salt:
- Metal oxidisers are salts, they may be hygroscopic
- Finished stores must be sealed
- if reactive with water,, metal salts will produce hydrogen gas
- may cause dangerous pressure which may break the integrity of a seal
Impurities:
- Some pyrotechnic items contain impurities that over time can cause changes to performance.
- Screening Smokes use zinc oxide which reacts with carbon dioxide from the atmosphere forming zinc carbonate resulting in drastic modification of the burning characteristics.
- Possibility of undesired chemical reactions are prevalent.
- The end result may not just be degradation of performance, it may be spontaneous ignition.
What is the role of a first fire composition?
Acts as the booster between the low energy output of the initiator and the main composition which may be difficult to ignite.
Pyrotechnic devices generally consist of the main composition pressed into a container.
On top of this is added a layer of composition that is designed to accept the output of an initiator.
This layer has many names: First fire. Igniter. priming composition. starter compositions.
What are the requirements of a first fire composition?
Be capable of igniting the initiator.
Generate a large amount of controlled heat,
not too rapidly or violently.
Not react violently may cause first fire
comp to blow off the main comp causing a
failure in ignition.
Not be too sensitive and should have an
output matched to the main composition.
Explain danger markings on pyrotechnics
All services adopted common system for marking
The current warning marking is: (in red on white in two places) DANGER DO NOT TOUCH NOTIFY POLICE (SERVICE OF ORIGIN)
What are the means of igniting or initiating cap igniters or detonators?
Mechanical means:
Mortar Primary Cart
Electrical means:
Detonators
Igniferous:
Non Elect Det
What are caps, also called primers?
What are the used in?
Caps, also known as primers a small cup
into which a small amount of sensitive
explosive is pressed.
Metal used must have the following qualities:
- Expand easily to provide obturation
- Strong enough to withstand striker blow.
- Contain the explosion of the composition.
Used in:
- mortars
- SAA
- Artillery cartridge cases
- Grenades
- Pyro comps
list characteristics of a mortar primary cartridge
Simple cap and anvil system.
Cap mounted internally.
Safer to handle.
Requires strong blow to unseat plunger.
List SAA ignition systems?
Three types of ignition system:
Cap and Integral Anvil (Berdan)
Cap and Separate Anvil (Boxer)
Rim Fire
List characteristics of an Artillery cartridge case?
Primer contains a cap for initiation.
Percussion or electrical.
Cap ignites charge in primer magazine.
List the ideal requirements for cap compositions
Stability over long storage periods under adverse weather conditions.
Optimum sensitivity to applied stimulus.
Optimum output.
Compatible with materials in contact wit them.
Safety in loading and handling.
Should not contribute to corrosion or erosion.
List the ingredients of a cap/primer compositions?
Primary Explosive
- lead styphnate
- potassium chlorate
Sensitiser
- powdered glass
- sulphur
Oxidiser
- Potassium chlorate
- barium nitrate
define an initiator
A small quantity of a heat or shock sensitive
explosive used to start the process of
combustion, explosion or detonation.
Types:
disruptive
igniferous
Caps and igniters lesson, Igniferous:
When used in igniters, the function of the
initiator is to ignite?
Propellant
Primers
Delay element
Gaines
What is the function of disruptive initiators?
When used in Detonators the function is to
directly induce detonation in the next
component of the explosive train.
Contains very sensitive HE.
Detonators can be subdivided into:
- Fuze detonators.
- Demolition detonators.
Explain detonators - a disruptive initiator
Detonators are normally small compared to
the filling that is to be initiated.
Maximum output is required for effective
initiation.
Usually requires a secondary explosive boost.
Requirements / Properties of Disruptive Initiators; - Violent and high V of D. - Sensitive to small shock. - Insensitive to normal handling. - Stable. - Minimally affected by moisture and temperature variations
What can fuze and demolition detonators be initiated by?
Fuze Detonators can be initiated by;
- Pyrotechnic delay
- Stab
- Electrically
Demolition Detonators can be initiated by;
- Pyrotechnic delay (Fuse Blasting Time)
- Electrically
- Shock (Nonel Firing System)
- Percussion (Booby Trap Devices)
What is the purposes of smoke?
Tactical Screening Smoke.
Signalling Smoke.
What are the ideal properties of smoke compositions?
Immediate in effect.
Unaffected as far as possible by climate/weather.
Persistent.
Non Anti Personnel.
Non Incendiary.
What are the two types of screening smoke?
Tactical or defensive smoke
list considerations for tactical smoke
Denies the enemy observation of our own
troops or installations, and is usually part of an overall strategy.
Smoke should be produced for relatively 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.
List considerations for defensive smoke?
Used to hide our troops in a emergency
situation.
Screen is therefore required to build up very
rapidly.
Without harassing personnel or fire risk.
Screening agents include?
White Phosphorus (WP)
Berger compositions
List characteristics of WP
Melts at 44 degrees
Burns/oxidises on contact with air.
Ignition temperature of 30 degrees
Producing thick white smoke.
Filling for projectiles and grenades.
Ammunition normally include a small HE
charge to:
-Scatter WP.
-Heat WP to ignition temp.
What are the advantages and disadvantages of WP?
ADV:
-Immediate effect on burning.
-Excellent screen produced (Excellent
Infra red screening agent).
-No priming or ignition devices required.
DIS
-Pillaring effect on bursting.
- Severe burns.
- Harassing effect on eyes, nose and throat.
- Fire risk.
- Expensive method of filling.
- Isolation in storage and transportation.
What is red Phosphorous (RP) used for and how is it made?
Indicate the point of burst in some HE rounds
and has replaced WP hand grenades in most
forces.
Made by heating WP to 240 o C for several
hours with iodine, then boiling with caustic
soda to remove any remaining WP.
Heated under pressure to 610 o C it reverts to WP.
Heating and pressure is provided by the
detonating of the bursting charge.
List the advantages and disadvantages of berger compositions
ADV:
- No pillaring effect.
- Minimum fire risk.
- No anti personnel effects (although there can be some issues with prolonged exposure).
- No harassing effect.
- Normal filling method.
DIS:
-Requires special priming and ignition
devices.
-Effective screen takes longer to build up.
Define how smoke is produced, what types are there?
Smoke can be produced by chemical or
pyrotechnic means, as well as by vaporising
mineral oils, which condense in the
atmosphere as droplets.
Chemical, pyrotechnic and other smoke compositions (zinc powders and oxides with HC etc)
Which five coloured smokes are currently seen in service?
Orange (sea distress) red yellow blue/voilet green
What is the best way to produced good coloured smokes?
By vaporising dyestuffs
What are the two types of coloured smoke?
Bursting and burning
HE additives lesson:
What are the purpose of additives?
Increase sensitivity
Improve stability
Increase blast effects
Improve moldability
Decrease sensitivity
HE additives lesson:
De-sensitizes
Aluminium
stabilisers
plasticisers
Explosive taggants
