Explosive and propellants Flashcards
What components make up guncotton?
NC, Nitric Acid and Cotton Fibres
What was added to picric acid explosives to increase the effectiveness?
Tetryl as a booster for amplification
What are the ingredients for greek fire?
Sulphur, pitch, naphtha
What are the pyrotechnic groups?
Illum Compositions Smoke Compositions Signal Compositions Delay Compositions Tracer Compositions Priming Compositions Simulators Pyromechanics
What are the effects of pyrotechnics?
Heat
Light
Smoke
Noise
What is added to make pyrotechnic colours?
Red- Strontium nitrate Yellow- Sodium nitrate Green- Barium nitrate Orange- Calcium nitrate Blue- Copper carbonate White- Barium and potassium mixture
What are the characteristic of primer compositions?
- Easy to ignite
- Generate high heat
- Not burn to quickly or violently
- Produce some solid products of combustion
- Be compatible with the mixtures used
Describe Primary Explosive?
A substance or mixture of substances used to initiate a detonation or a burning reaction
What are the types of explosive initiators?
Distruptive- Detonators
Igniferous- Igniters
What colour produces red smoke?
Strontium nitrate
What does ballisite consist of?
Nitroclycerine, nitrocellulose, camphor (wax)
What are the 4 types of propellant?
Single Based propellant- NC
Double based propellant- NC and NG
Triple Base propellant- NC, NG and Nitro Guanadine (Picrite) - NGu or NQ
Composite based propellant
Flash receptive detonators are 1 type of explosive, what are 4 others?
- Flash receptive detonators
- Stab igniters and detonators
- Percussion igniters
- Hot bridge wire igniters and detonators
- Exploding bridge wire detonators
Give an example of some low explosives?
- Gunpowder
- Pyrotechnics
- Propellant
Give an example of some high explosive?
Tetryl, Comp B, RDX, CE, PE4, C4, PETN, TR1, HMX, TNT
What is the compositon of “COMP B”?
RDX- 59.5%
TNT- 39.5%
WAX- 1%
What purposes do additives have in high explosives?
1- Decrease Sensitivity 2- Increase Sensitivity 3- Increase Moldability 4- Increase Stability 5- Increase Blast Effect
Caps and primers contain 3 primary components what are they?
1- The primary explosive
2- The oxidiser
3- The sensitiser
What is the purpose of a dark ignition tracer?
- To avoid observation of exact location of weapon
- To avoid dazzling the gun layers at night when fired from multiple/automatic weapons.
What are the design requirements for illumination?
- Withstand firing forces
- Must have the correct luminosity
- Must burn for the correct time
What are the ideal properties for smoke?
- Immediate in effect
- Unaffected as far as possible by weather
- Persistent
- Non anti personal
- Non incendiary
What is the main use for armies using smoke?
Tactical Screening Smoke
-Tactical smoke, defensive smoke
Signalling
What other metals are added to High Explosives to increase heat?
Magnesium and aluminum and Zirconium
What is the definition of delay? What is it used for?
To provide a pyrotechnic delay between the igniting or explosive events.
Define propellant?
Propellants are an explosive which by controlled burning provides gas pressure required to give motion to a projectile or missile.
What explosive was found when they were creating RDX?
HMX
What are the advantages of single based propellant?
- Cooler burning, therefore less erosive
- Generate considerably less flash than cordite
- Ballistics less effected by change in change of temperature
Advantages of double based propellant?
- Easy to ignite
- Higher energy rating than sinlge based
- Higher flame temp
- Higher burning rate
What additives are in propellant?
SPCFADSS
SPCFADSS
- Stabilizers
- Plasticisers
- Coolant
- Surface moderants
- Surface lubricants
- Flash inhibitor
- Decoppering agents
- Antiwear additives
What are the main chemicals used as a De-coppering agent?
Tin and Lead
How is the rate of burning controlled?
Size, Shape, Composition
What are the different types of burning?
Progressive- Total surface area increases during burning- Rosette, Multi tubular
Degressive- Total surface area decreases as the propellant burns- Cord, flake, strip/ribbon
Neutral (constant)- External surface decreases at the same rate that internal surface increases during burning- Tubular, cogged, star centre
Name the propellant shapes that have a constant burn?
Tubular, Cogged, Star Centre, Slotted Tubular
What is a carbamite?
- Plastiser- Increase shelf life
- Stabiliser- Moldability
- Coolant- Reduce burning temp
- Surface moderant- Act similar to coolants but on the outer layer
Explain burning to detonation
Occurs when there is an abrupt acceleration of flame which becomes a shock wave, that ignites and becomes overpressured to ignite an item.
What are the two types of high explosives and examples?
Primary - sensitive to heat shock or friction. Lead azide, Mercuary fulminate, lead styphlinate
Secondary - less sensitive to stimuli such as heat, shock and friction. RDX, TNT,
What does wax do?
Binding agent/De-sensitiser
Incendiary compositions fall into 2 categories, what are they?
- Metals and alloys
- Combustible fluids
What does composite explosive mean?
CE- Tetryl- Booster
What are the Explosive names for the following?
Cyclotrimethylenetrinitromine- TRIN
Cylotetramethylenetetranitramine- TRAN
TRIN- RDX
TRAN- HMX
What was the historical composition of gunpowder?
Saltpeter- 7 parts
Sulphur- 5 parts
Charcoal- 5 Parts
What century was saltpeter refined?
14th Century
Define HE?
Any explosive which once initiated decomposes almost instantaneously into its original molecular structure by the passage of a detonation wave through it, subsequently production of heat and gases and liberation of great energy.
What is the purpose of delay Compositions?
To provide a pyrotechnic delay between two igniting or explosive events. Pyrotechnic delays are trains of composition, which burn in cigarette fashion from one end to the other.
2 Categories of propellants? and sub categories
Liquid Propellant- Mono propellant, bi-propellant
Solid Propellant- Colloidal, Composite
What are the velocities of detonation for the following?
TNT CE PENT RDX ANFO COMP B
TNT- 6950 m/s CE- 7500 m/s PENT- 8300 m/s RDX- 8450 m/s ANFO- 1100-2700 m/s COMP B- 7800 m/s
Factors effecting V of D?
- Density of the charge
- Charge diameter
- Degree of confinement
- Strength of detonator
What is the purpose of additives used in HE?
Increase sensitivity Increase blast effect Improve stability Improve mouldability Decrease sensitivity
Definition of a pyrotechnic?
A material capable of combustion when correctly initiated to produce a special effect.
Define Detonation
An extremely rapid chemical change with the evolution of heat and gas, accompanied by a violent disruptive effect and intense blast.
Two types of explosives?
High explosives- TNT, RDX, COMP B
Low Explosives- Propellant, tetryl, ignitors
Define low explosive?
An explosive substance, which decomposes rapidly through combustion with the evolution of heat and flash and generates large quantity of gaseous products.
Define deflagration?
Describes subsonic combustion that usually propagates through thermal conductivity.
Define igniter compositions?
A composition that produces hot flames, usually accompanied by sparks and hot gases, for relatively short times.
