Summative 3 -Target Analysis (2.2.5+2.2.2) Flashcards
Blast effects and FAE: Explosions
Definition:
recite at least one, of the four, definitions of an explosion
A nuclear, chemical or physical process leading to a sudden release of energy.
An explosion is the violent and rapid decomposition of energetic material to which will lead to violent pressure rupturing of any confining structure.
The violent expansion of gas at high pressure resulting in a shock wave and significant overpressure.
The explosion frees energy in the form of heat, light and a large volume of gas.
Blast effects and FAE: Explosions
List:
What are the three types of explosion?
Physical Explosion.
- natural - eg lighting strike, volcano
- structural - eg failure of a gas cylinder
Chemical Explosion.
Nuclear Explosion
Blast effects and FAE: Explosions
definition and list:
Define a chemical explosion.
List the four things that must be exhibited to qualify as a chemical explosion
The sudden expansion of gases into a volume much greater than the initial one, accompanied by noise and violent movement extremely rapid reaction of a chemical system to produce heat and gas.
Rapid expansion
Evolution of heat
Rapidity of reaction
Initiation of reaction
Blast effects and FAE: Explosions
Definition
Define a nuclear explosion
Sudden release of enormous quantities of heat by fission or fusion processes.
Blast effects and FAE: Explosions
Definition
Define the effects of an explosion, for both above and below ground
When ordnance functions, the explosive fill is rapidly changed into an expanding mass of hot gases accompanied by heat, light and noise.
Above Ground;
- Effect caused from blast and fragments.
Below Ground;
-Effect caused from ground shock, blast and ejecta.
Blast effects and FAE: Explosions
List
What are the three primary effects of an explosion?
Blast
Heat
Fragmentation
Blast effects and FAE: Blasts
Definition
Define a blast
Violent disruptive effect caused by an explosion. From the explosion there is an evolution of heat and gases and a shock front which emanates from the centre of the explosion.
Blast effects and FAE: Blasts
List
List the three main phases of a blast
Has a shock front
Followed by a positive pressure phase;
- High pressure gas behind the shock front.
Then followed by a negative pressure phase;
- A rarefaction following the positive phase.
Blast effects and FAE: Blasts
List / Definitions
List the four types of blast pressure and their definitions.
- Dynamic Pressure:
Results from the high wind velocity & increased density of the air behind the shock front.. - Incident Pressure:
Pressure exerted at right-angles to the direction of travel of the shock front. - Quasi-Static Pressure:
Results when an explosion occurs within a structure - overpressure eventually settles to a slow decaying level. - Reflected Pressure:
Instantaneous build up of pressure occurring when a shock front strikes a rigid surface in it’s line of travel.
Blast effects and FAE: Blast waves
List
What are the four behaviors exhibited by blast waves?
Reflection
Diffraction
Overpressure vs Distance
Overpressure vs Time
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Reflection
The blast wave is thrown back at an angle to the original path.
The bouncing back of a wave after it strikes a boundary:
- Incident wave - the incoming wave.
- Reflected wave - the wave that is bounced back.
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Diffraction
Breaking up or scattering of a wave by an obstacle.
Blast effects and FAE: Blast waves
Definition
Explain the concept of Mach Stem, in reference to blast wave behaviours.
Occurs when reflected blast wave coincides with the original wave.
Reflected wave is moving faster through the air already driven forward by the blast wave.
The two waves combine to increase the pressure.
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Overpressure vs distance
The peak overpressures fall over distance:
– loss of energy due to heating of the atmosphere.
– Inverse-Square relationship of the wave pressure to distance due to
spreading.
Blast effects and FAE: Blast waves
Definition
Define the blast wave behaviour: Overpressure vs time
Behind the high pressure front the elasticity of the air causes the formation of a rarefaction or negative pressure phase.
This is somewhat longer duration than the positive phase.
Blast effects and FAE: FAE
List / Definition
List the three basic principles of a fuel air explosive (FAE)
Creating an aerosol cloud of fuel air mixture.
Which is then detonated to achieve an explosive effect
Not to be compared with the incendiary effect of napalm etc.
Blast effects and FAE: FAE
List
List the six types of fuel used in FAEs
Acetylene
Butane
Ethylene oxide
Kerosene
Propylene oxide
Aluminium
Blast effects and FAE: FAE
List
List the four steps that an FAE goes through, as the device functions
- Rapidly disseminated by an explosive bursting charge to form a cloud in the air.
- Fused to provide a delay after the initial burst during which the cloud expands to its optimum size.
- The fuze initiates or ignites which causes the cloud to burn to detonation.
- The blast wave forms inside the cloud and proceeds unabated to the edge of the cloud. The overpressure is therefor very high when the wave is an appreciable distance from the point of initiation.
Blast effects and FAE: FAE
List
List the 2 advantages of FAEs
List the 1 disadvantage of FAEs
ADV:
FAE provides larger overpressures at greater distances than HE would provide.
Requires little or no oxygen in the molecular structure therefore making a FAE explosion 3 to 5 times hotter than HE.
DIS:
FAE is dependent on weather conditions.
- Strong winds would prevent the development of the optimal shape from the initial burst.
Blast effects and FAE: FAE
List
List the three specific areas of testing regarding the improvement of FAE
Consistency in the size and mixture of the aerosol.
Means of delivery.
Precise control of detonation.
Blast effects and FAE: FAE
List
List the seven targets that FAE are effective against?
Structures. Concentrations of AFV and SP Guns. Parked aircraft. Minefield clearance. Ships. Bunkers / trenches. Concentrations of troops in the open.
Blast effects and FAE: FAE
FAE are a type of what effect?
this effect can also occur in sawmills, bakeries, silos etc.
Thermobaric
Target analysis:
Define
What is Overall Kill Probability?
The framework most frequently used by a weapon system designer on which to base an assessment of the effectiveness of his system is the concept of the overall kill chance.
Target analysis:
Definition.
Regarding the overall kill probability, show and explain the formula for the Probability Product Rule?
Probability of a kill (Pk)
– One round engagement.
Cumulative effect for multiple rounds.
PK = PH x PR x PL
Where:
P K = Probability of a Kill
P H = Probability of a Hit
P R = Reliability of the weapon system
P L = Lethality of the warhead or ammunition
Target analysis:
List / Definitions
List the three damage levels used in damage assessments, and define each one.
- Disablement
Disablement of the target to prevent it from doing it’s job is the damage level the ammunition designer aims to achieve. - Destruction
Destruction of a proportion of the targets engaged is an acceptable bonus. To design for destruction of the target leads to substantial overkill. - Neutralisation
The neutralising effect of fire stems from the apprehension induced in the target that the warhead propelled at it has a casualty causing potential.
It is therefore people, rather than material, which can be neutralised.
Target analysis: Damage levels
List
What design consideration should be considered when designing a weapon?
Weapons should be designed to attack the most important targets.
It is also necessary to design a piece of ammunition that will achieve a particular level of damage against a known target.
Target analysis: Types of targets
List
List the six types of targets frequently targeted by fire
People
Vehicles
Structures
Equipment
Aircraft
Complex
Target analysis: Types of targets
List
List factors influencing targeting of People
- Factors which affect their vulnerability are:
Attitude - presented area.
Protection equipment - body armour, occupation of buildings. - People are not simple targets but complex.
Target analysis: Types of targets
List
List factors influencing targeting of Vehicles
- The armoured vehicle is one of the principal targets.
- Main protection has to be defeated first with armoured vehicles:
ERA
Laminated armour
MBT - primary target
LAV, IFV, APC still require special consideration - Soft skinned vehicles are less of a problem:
Mobility
Less/no armour protection
Target analysis: Types of targets
List
List factors influencing targeting of structures
These range from the lightly constructed billet to the reinforced concrete bridge or strongpoint.
Because of the diversity of targets in this group, it is not economic to design a special warhead for each.
Target analysis: Types of targets
List
List types of equipment which can be targetted by ground forces
- Material found around the battlefield, principal types: Soft skinned vehicles. Aircraft on the ground. Storage dumps/maintenance areas. Electronic and communication equipment.
Target analysis: Types of targets
List
List the categories of Aircraft in flight targets
- Aircraft in Flight. This category of target is complex. The group presents particular problems of target acquisition and chance of kill. It is convenient to sub divide this target into:
Fast Moving Aircraft. This includes tactical strike aircraft, fast reconnaissance aircraft and certain drones and unmanned machines.
Slow Moving Aircraft. This includes transport aircraft and others, which operate at speeds of 200 300 knots.
Helicopters.
Target analysis: Types of targets
Definition
Define a complex target
Targets that have several different elements, generally people in combination with other types of target.
Target analysis: Target effects
Definition
Define Target effects
All targets need to be subjected to an attack IOT produce a physical effect, which is capable of causing casualties to people and disruption to and/or destruction of other targets.
Psychological and physiological effects can be achieved against people. However, this is difficult to quantify (except in the case of NBC attacks).
Target analysis: Methods of achieving target effects
List
regarding development and production, list the four qualities a weapon system must possess.
Simple.
Easy to make.
Easy to inspect.
Safe to transport, store and handle.
Target analysis: Methods of achieving target effects
Regarding development and production, what should be designed first:
the Warhead, or the means of delivery?
The warhead:
In practice, the weapon system design frequently precedes that of the warhead or a new warhead is required to boost the performance of an existing weapon.
In principle this approach is wrong.
Target analysis: Methods of achieving target effects
List
For conventional attack, what are the two practical ways of producing energy to a achieve an effect?
- Kinetic Energy (KE)
In the form of a solid missile (a “shot”) which dissipates its energy on impact and requires no triggering device to control the energy release. - Chemical Energy (CE)
In the form of a substance, which has considerable potential energy relative to its mass, which can be released when suitably initiated.
Such substances are known as high explosives and the initiation mechanism as a fuze.
Target analysis: target Groupings and key targets
List / Definition
List the three types of key targets that may present themselves to land forces
People
Attack of Armour
Aircraft in Flight
Target analysis: Target groupings
Reasoning
What are the two reasons we select specific key targets to counter rather than producing a large range of ammunition to counter anything found on the battlefield?
- It is unacceptable as well as impractical at the R & D phases,
- and the logistic implications make this approach uneconomic.
Attack on Aircraft: History
List
List 5 points on WW1 era anti air efforts.
Early biplanes: Slow and flimsy, easily damaged
Airships/Zeppelins: Slow, flammable gas bags
Machine guns
Searchlights
Modified artillery
Attack on Aircraft: History
List
List seven points on WW2 era anti aircraft efforts
Faster metal frame and skin aircraft
Dive bombers ~ Kamikaze
Multi engined bombers
Early jets
Dedicated AA guns
Radar
VT Fuzes
Attack on Aircraft: General principals
List
List the two general principals regarding the nature of the target.
Types of Aircraft targets
- fast moving
- slow moving
- helicopter
Vulnerability
Attack on Aircraft: Damage criteria
List
List the six damage criteria in the most commonly used criteria group
KK Kill The target suffers immediate and catastrophic disintegration.
K Kill The target is destroyed in less than 10 secs
A Kill The target is destroyed in less than 5 mins.
B Kill The target is defeated in less than 5 hours.
C Kill The target’s mission is not achieved (mission aborted)
E Kill The target may complete its mission but needs repair before it can fly again.
Attack on Aircraft: Aircraft vulnerability
List
List the 5 main areas of vulnerabilities on aircraft, including sub-areas
Structural Attack:
- Air frame.
- People, the aircrew.
Structural Attack:
- Fuel cells/tanks & lines.
- Engines.
Power transmission systems.
Flight controls.
Avionics.
Bomb load / Pay load.
Attack on Aircraft: Aircraft vulnerability
List
List 6 ways of reducing vulnerable areas
Armouring.
Burying sensitive components.
Concentrating sensitive components.
Duplicating components.
Separating components.
Self sealing fuel tanks.
Attack on Aircraft: Warheads
List
List the 7 common types of warheads
Blast:
- External
- Internal
Fragmentation (Inefficient 80% Wasted)
Fragmentation plus blast
Special kinetic energy:
- Discrete rod
- Continuous rod
Shaped charges
Sub projectiles
Cluster
Attack on Aircraft: Warheads
Reason
What factors can affect the effectiveness of a fragmenting warhead, explain the reason.
Fragment Mass - more fragmentation in smaller pieces is required to cover a larger area than conventional ground forces HE
Fragment Pattern - The designer is concerned with the shape of the frag beam width, and the density of the frag in the beam, as well as individual frag mass. The beam (frag spread) can be controlled to some extent by altering the shape of the warhead
Fragment Velocity - The designer strives for as high a velocity as possible. Most aircraft contain large amounts of aluminium - under a high energy impact this material burns and gives rise to a possible ignition source for fire plus pyrophoric effect.
Different configurations of frag, and the HE used to disperse it, can drastically change the way the frag spreads in the air at the point of detonation
Attack on Aircraft: Effects of altitude
List
What 4 factors affect warheads as altitude increases?
Density
Attenuation
Miss Distance
Altitude increases/warhead increases
Attack on Aircraft: effects of altitude
Definition
Explain miss distance,
why is modern development focused on miss distance rather than charge size
Miss distance is the distance that the warhead is designed to detonate from the aircraft.
Larger charge means larger, or more robust, delivery system, and the effects of altitude diminish the returns on larger warheads (10ft = 10lbs charge, 30ft = 270lbs charge)
Attack on Pers: Types of damage
List
List the two types of damage and their effects
Physical
- Casualties
- Damage to materiel
Mental
- affects will to fight
- Difficult to quantify on a well disciplined enemy
Attack on Pers: The target
List
The human is small and complex. What are the consideration of a human as a target?
- The human is small and complex: Measures around 0.42 m 2 Protected by CBA, helmet, eye protection, clothing. Standing, lying or moving. Fit, alert, tired, depressed. Bone, muscle, nerves, vulnerable areas. Injured by blast, frag or both.
- Target assessment difficult.
Attack on Pers: Modes of attack
List
What three things does the most efficient mode of attack require?
High probability of a hit.
Rapid transfer of energy.
No unnecessary overkill.
Attack on Pers: Modes of attack and frag
List
What are 3 common examples of energy transfer via frag?
What are three ways to produce frag?
Examples:
Grenades, mortars, projectiles
Ways of producing:
Generic HE, pre notched containers, pre formed frag
Attack on Pers: Control of Frag mass and velocity
List
list 4 ways that size of frag can be controlled
Case material and its mechanical properties.
Thickness of the wall.
Quantity of explosive and its position in relation to the fragmenting case.
Velocity of detonation of the explosive.
Attack on Pers: Control of Frag mass and velocity
List
list 3 ways that velicity can be controlled
Amount of explosive behind the fragment wall.
Charge density and velocity of detonation.
Density of the wall material.
Attack on Pers: Control of Frag mass and velocity
List
list 3 ways that frag velocity can be achieved
Amount of explosive behind the fragment wall.
Charge density and velocity of detonation.
Density of the wall material.
Attack on Pers: Factors affecting performance
List
List 4 factors that affect performance of frag
- Distribution of Fragmentation:
Spin rate will influence the distribution but not the overall pattern.
Usually symmetrical about longitude axis.
Factors effecting this pattern Angle of arrival. - Orientation of projectile to target:
Effective distribution when projectile is vertical
As axis moves away from vertical, increasing amounts of frag is lost in the ground. - Height of Burst:
2-4m optimum.
Significant effect on performance of fragmenting device.
Achieved by fuze fitted to device. - Average Area of Exposed Target:
Disposition and equipment of the target.
Terrain the target is in.
Attack on Pers: Energy transfer
List
Severity and type of wound depends on what 3 things?
Actual energy transferred.
Rate of transfer of energy from projectile to target.
Tumbling/yawing reduces energy transfer.
Attack on Pers: Factors affecting energy transfer
List
List the 3 factors affect the transfer of energy from frag to a target?
Fragment mass and velocity.
Fragment cross sectional area.
Stability of the fragment.
Attack on Armour: History
List
What date did tank appear?
List 5 anti tank methods from the WW1 era
The first Tanks appeared 16 Sep 1916:
Methods of attack:
Large calibre rifles with hardened projectiles
Concentrated Machine gun fire
6 grenades tied together
Early blast mines
Flame throwers
Attack on Armour: History
List
List 5 methods of attack on tank in the WW2 era
20 50mm (early days of war)
Up to 128mm
AT mines
Shaped Charges / HESH
Recoilless rifles / Bazooka
Attack on Armour: Armour
List
List 7 types of armour used on armoured vehicles.
Rolled Homogeneous Armour (RHA)
Spaced Homogenous
Ply
Face hardened
Reactive Explosive Reactive Armour (ERA)
Composite (Chobham)
Slat (Bar)
Attack on Armour: Damage assessment
List
List the 3 criteria for tank damage?
M - Mobility kill
F - Firepower kill
K - Completely destroyed
Attack on Armour: damage assessment
List
List the 2 criteria for APC and MICV damage
F - Firepower kill
P - Payload kill
Attack on Armour: Forms of attack
List:
What are the 3 High Energy Forms of Attack?
Kinetic energy
Chemical energy
Combination of both
Attack on Armour: Shot failure
List
List the 3 ways that shot can fail on impact with armour
Shot Failure:
Barrelling
Shot Failure:
Shattering
Shot Failure:
Lateral Bending
Attack on Armour: Path of shot
What technique can be used to assist with penetration of sloped armour?
Use of a swivel nosed cap on the projectile.
Attack on Armour: Kinetic energy
List
List 5 ways of increasing penetration of kinetic shot and speak to each
- Lengthening of Barrel
There are obvious practical and physical
limitations to this idea - Rocket assist
This is best avoided in a gun fired kinetic energy form of attack. It results in a larger and heavier round, and may produce some loss of accuracy in the system. It should not, however, be ruled out. - Improve steadiness of shot
It is important, and every effort is made in practice to optimise this parameter. The design of the sabot and its separation technique has much relevance here. - Lengthen the projectile
Increasing the length may improve penetration, but it also introduces other problems like stability during launch and in flight, and the potential for break up at the target. - Use of Segmented Long Rod Penetrators
Trials have found that a short rod is more efficient in penetration. Due to the inertia of penetration continuing after the penetrator has been totally consumed.
Attack on Armour: Chemical energy
List
List the 5 factors affecting HEAT perfomance
Cone Diameter Shape of Liner Liner Material Stand – Off Distance Rate of Spin
Attack on Armour: Forms of attack
Definition
Define a kinetic source of energy
Define a chemical source of attack
KINETIC In the form of a solid missile which dissipates it’s energy on impact and requires no triggering device to control the energy release.
CHEMICAL In the form of a substance, with a considerable potential energy, relative to it’s mass, which can liberate that energy when suitably initiated. Such materials are familiar as High Explosive and the initiation mechanism as the fuse.
Attack on Armour:
List
List 4 considerations for the use of HESH
Design problems
Secondary effects
Performance against other targets
Lethality
Attack on Armour: Chemical energy
List
List the considerations of HEAT vs Plate Charge use
Manufacture Tolerances
Greater Stand Off
Rate of Spin
Penetration
Lethality
Attack on Armour: Combination of kinetic/chemical
List
What is the main consideration for using a combination of energies in ammunition?
The intense shocks to which a initiating mechanism is subject to on initial impact, presents a problem in design of combination ammunition.
Attack on Armour: BAE
List
BAE contribute, directly or indirectly, to the lethality of an attack.
List the 4 types of BAE
Luminescence
Spalling
Heat / Fires
Overpressure
Attack on Armour: Methods of delivery
List
List the 5 methods of delivery of attacking a tank
Guns
Grenades
Mines
Aircraft bombs
Missiles
HESH and HEP-T:
What are the general principles of HESH?
To detonate high explosive in contact with
armour plate
Sending a high velocity compressive shock
wave through the armour plate
When the shock wave reaches rear of plate,
the change in medium between plate and air
causes wave to reflect back through the
plate as a tension wave
When the rebounding tension wave meets
further primary shock waves exceeding the
strength of the plate
A large scab is detached from the rear
surface
HESH and HEP-T:
What is the size of the scab created by a HESH round?
What is the velocity range of a HESH scab?
Depends on calibre of weapon and thickness of armour but generally 1 1/4 to 1 1/2 times its own diameter.
Velocity of scab 30 - 130mps
HESH and HEP-T: Deign characteristics
List
List the 7 design characteristics for HESH
Head must be collapsible
Head must not be pointed
HE must have a high V of D
Explosive be plastic in nature
Fuze must be in the base
Inert bituminous pad in nose
Walls must have specific characteristics
HESH and HEP-T: Design characteristics
List
List the design characteristics for the wall of a HESH projectile
Be sufficiently strong
Ductile, for control over the flow of explosives
Not inhibit the sticking of the explosive to the
target
Confine the explosive
Provide a source of anti personnel fragmentation
HESH and HEP-T: Design problems
List
List the problems associated with designing a HESH round
- Delivery to target to ensure that the HE is in close contact with plate over a wide area at the moment of detonation
- Shock wave must be travelling towards the plate this means it must be initiated from the rear
- HE fill must be sufficiently insensitive to withstand impact on plate to prevent Reverse Impact Detonation (RID)
- Shell wall must be thin to facilitate spread of
explosive
HESH and HEP-T: design problems
Definition
What is Reverse impact detonation?
Detonation occurs before the fuze can produce detonation of the filling, the shock wave will be travelling in the wrong direction
HESH and HEP-T: Secondary effects
List
What are the 2 common secondary effects of HESH?
- Anti personnel effects from:
Fragmentation
Shock wave, even if no scabbing occurs - Damage to sensitive equipment
HESH and HEP-T: Defeating HESH
List
List the 4 ways that HESH can be defeated
- Spaced armour:
Air gap between layers of armour
HESH works against first layer only - Skirting plates:
Provides an air gap - Grooved:
Disrupts shock waves - Reactive armour:
Explosive from the reactive armour disrupts the
HESH shock wave
HESH and HEP-T: Performance
List
List 3 other targets that HESH performs well against
Emplacements
Pill boxes
Concrete structures
HESH and HEP-T: Performance
List
List 3 factors affect the performance of HESH?
- Calibre:
Thickness of plate defeated is proportional to the calibre. - Angle of Attack:
Limited to the angle at which ricochets start, around 65 degrees
Functioning can be expected up to 60 deg.. - Striking velocity:
Too much velocity and the projectile may malfunction due to impact initiation
Shock detonation
Kinetic Energy Attack on Armour:
Definition
Describe a kinetic energy attack
- Kinetic energy attack can be described as:
Hitting the target armour with a projectile of
sufficiently high velocity to achieve penetration
Aim is to direct as much energy as possible on
to a small area of the target, optimizing
penetration.
Kinetic Energy Attack on Armour: Ballistics
Which provides greater Kinetic Energy to a kinetic penetrator, Velocity or Mass?
Velocity:
Ek = 1/2MV^2
Kinetic Energy Attack on Armour: Ballistics - internal
Reasoning
To achieve the greatest muzzle velocity, a kinetic projectile should have what two properties?
A wide base, IOT to maximise area for propellant to work against,
and low mass to overcome.
Kinetic Energy Attack on Armour: ballistics - external
List
List the 4 things that can prevent a round from becoming too slow whilst moving through air.
Small cross sectional area
High Mass
High initial Velocity
Aerodynamic design
Kinetic Energy Attack on Armour: Ballistics - terminal
List
List the 4 things required for good quality terminal ballistics
Small cross sectional area
High mass
High velocity
Hard material
Kinetic Energy Attack on Armour: Stabilisation
List
What are the two methods of stabilising a round?
What ratios are used for each?
- Spin
7: 1 length:diameter ratio for spin - Fin
15: 1 length:diameter ratio for fin
Kinetic Energy Attack on Armour: Types
List
Expand the following acronyms APCBC APCR APCNR APDS-T APFSDS
APCBC: armour piercing, capped, ballistic capped
APCR: armour piercing, composite rigid
APCNR: armour piercing, composite non-rigid
APDS-T: armour piercing, discarding sabot, trace
APFSDS: armour piercing fin stabilised, discarding sabot
Kinetic Energy Attack on Armour: Discarding sabots
List
What are the two types of discarding sabots?
Petal
Pot
Kinetic Energy Attack on Armour: APDS
List
APDS maximises ballistic qualities, maximising velocity.
What are the 3 basic steps of APDS operation?
Burning propellant pushes on base of pot.
Weak ring shears.
Petals discards radially.
Kinetic Energy Attack on Armour: APFSDS
Reason
Improved armour required improved rounds,
What quality was changed from APDS to improve performance and why?
Longer and thinner penetrators gave better penetration, however longer penetrators were liable to bend or break on impact.
therefore, increased length is dependent on improved materials and stabilisation.
Kinetic Energy Attack on Armour: APFSDS
List
List the 5 characteristics of APFSDS
The shot is still contained in a discarding sabot.
Fired from either smooth-bore or rifled barrels.
Slipping driving bands reduce spin when fired from rifled barrels.
The sabot of an APFSDS projectile is difficult
to discard:
-Aerodynamic forces and residual gas pressure utilised.
Muzzle velocity 1500ms.
Kinetic Energy Attack on Armour: Development
List
List 5 areas where development is occurring
Move to DU:
- Self sharpening
- Pyrophoric effect
Energetic propellants.
Higher diameter: length ratios.
Higher calibre (up to 140 mm).
Electromagnetic - hyper-velocity projectiles.
Shaped Charge attack: Define
Definition
Define a shaped charge attack
A charge shaped so as to concentrate its explosive force in a particular direction.
Shaped Charge attack: History
List
Briefly talk to the History of Shaped Charges,
2 people, 2 dates.
Charles Munroe 1888:
A civilian chemist working at the U.S. Naval torpedo Station, Rhode Island.
Explosive guncotton with the manufacturer’s name stamped into it was detonated next to a metal plate, the lettering was cut into the plate.
If letters were raised in relief above the surface of the explosive, then the letters on the plate would also be raised above its surface.
Egon Neumann 1910:
Discovered that a block of TNT, which would normally dent a steel plate, punched a hole through it if the explosive had a conical indentation.
Shaped Charge attack: principle
Definition
What is the principle idea on which a shaped charge is based?
If the energy from a high explosive charge could be focused or channelled to a point, it would be reasonable to expect that extremely high local energy levels could be achieved.
Shaped Charge attack: Method of defeating Armour
List
List the 5 broad steps outlining the functioning of shaped charge against a Armour plate
Achieved by hollowing out the front face of a slab of high explosives to give a conical shape.
The energy from the detonation of the explosive is directed inwards and forwards as a gaseous jet.
If a metal liner is placed on the front of the HE charge it will collapse and be carried forward.
The gaseous jet, with metal particles from the liner flowing in it, has an extremely high velocity.
At its tip, the jet velocity is of the same order as the velocity of detonation of the high explosive.
Shaped Charge attack: Method of defeating armour
Definition
A shaped charge does not erode or melt the target plate.
How does a shaped charge penetrate an armour plate, and why is it effective? What law governs this effect?
It penetrates by Intense Concentration of Kinetic Energy using the chemical energy of the explosion as its driving force.
As the tip of the jet has a velocity in the same order as the VoD of a HE, it is an effective penetrator as:
KE=1/2MV^2
Shaped Charge attack: Fuze
Definition
What kind of initiation or fuzing does a shaped charge use?
It uses a point initiated, base detonating fuze (PIBD)
Shaped Charge attack: Lethality
List
What kind of effects does a shaped charge have post penetration?
What are the secondary effects?
Similar effects to a kinetic energy attack, the residual energy is in the:
Metal fragments
The jet itself, being a hot, high velocity with metallic content
Anit-pers from fragmenting shell casting.
Shaped Charge attack: Physiological effect
List
What are the main physiological effects of a heat penetration?
The effects are pressure, temperature rise and intense luminosity.
The pressure rise produced by a warhead of about 100 mm cone diameter is sufficient to damage the unprotected ear.
The temperature rise is potentially a source of danger, whilst luminosity of the jet can produce dazzle if an individual is looking directly at it.
Shaped Charge attack: Factors affecting performance
List
Cone diameter: speak to the effect of cone diameter
Cone as near the full diameter of the warhead
as possible.
Penetration is proportional to CD i.e. double
CD, double penetration.
Shaped Charge attack: Factors affecting performance
List
Shape of Liner: speak to the effects of the shape of the shaped charge liner.
Angle of cone can be varied to control shape of the jet.
A trumpet shaped liner enhances the effect and is now widely used.
For the defeat of armour a high degree of dimensional accuracy and good surface finish are required.
Shaped Charge attack: Factors affecting performance
List
Liner Material: what are the advantages/disadvantages pf the three common metals in regards to liner material.
Copper is most commonly used deforms easily.
Steel reduced penetration and corrodes in long term storage.
Aluminium reduced penetration, increased thermal affects.
Shaped Charge attack: Factors affecting performance
List
Stand of Distance :speak to the effect of stand off distance
Stand Off Distance This is the distance between the front face of the shaped charge liner and the target plate at the moment of initiation of the high explosive.
2 CD Little degradation.
5 CD Peak performance.
It is, however, difficult to ensure functioning at the optimum stand off in a projectile as opposed to a static charge and consequently ideal stand off is seldom achieved.
Shaped Charge attack: Factors affecting performance
List
Stand of Distance :speak to the effect of stand off distance
Stand Off Distance This is the distance between the front face of the shaped charge liner and the target plate at the moment of initiation of the high explosive.
2 CD Little degradation.
5 CD Peak performance.
It is, however, difficult to ensure functioning at the optimum stand off in a projectile as opposed to a static charge and consequently ideal stand off is seldom achieved.
Shaped Charge attack: Factors affecting performance
List
Rate of Spin: speak to the effect of spin on HEAT
Mass appreciably greater than a purely gaseous jet due to metal liner.
Susceptible to centrifugal force induced by the spin of a projectile.
Recent research has indicated that improvements in penetration can be achieved by minimal spin in a certain direction.
Shaped Charge attack:
List
What three things can compensate for spin in HEAT round
Slipping driving bands:
- Carl Gustav 84 mm HEAT round.
Fluted liners:
- Attack Helicopter 30 mm HEDP round.
Spin compensated liners.
Shaped Charge attack: Plate Charge
List
List four alternate names for a plate charge weapon
Miznay-Schardin effect.
Plate Charge.
Explosively Formed Projectile (EFP).
Self-Forging Fragment (SFF).
Shaped Charge attack: Plate charges
List
List 4 points that speak to how and where plate charges are used.
Warhead can be some distance from target.
Use in sub projectiles.
Degree of guidance desirable due to directional effect.
Numerous plates from one detonating source.
Shaped Charge attack: Plate charge
List
List 5 points that, in use, plate charges differ from HEAT rounds
Less sensitive to variations in manufacturing tolerances.
Less sensitive to stand off variations. Penetration of at least one CD can be achieved at distances of 1,000 CDs stand-off.
Insensitive to warhead rate of spin.
At least 50% less efficient at penetrating armour. Penetration of between 1-2 Cd is the norm.
More lethal, given that penetration does occur.
Shaped Charge attack: History and names
List
What are the names of the two effects that the govern the principles of HEAT, and Plate charges,
HEAT - Munroe effect
Plate charge - Miznay-Schardin effect.
Blast effects and FAE
What are the effects of reflection on the blast wave?
The blast wave is thrown back at an angle to the original path.
Blast effects and FAE
What is the basic principles of FAE?
Consists of creating an aerosol cloud of a fuel air mixture, which is then initiated to create an explosive effect (not a fire such as napalm)
Blast Effects and FAE
Define Blast
A violent disruptive effect aused by an explosion. From the explosion there is an evolution of heat and gasses and a shock front which emanates from the centre of the explosion.
Shaape Charge Attack
What are the factors affecting the performance of shaped charges?
Cone Diameter Liner Material Liner Shape Stand-off Distance Rate of Spin
Shape Charge Attack
Within a shape charge, the residual energy lies within what?
Unconsumed part of the jet
Fragments of mental
HESH and HEP-T
What are the factors effecting the performance of HESH?
Calibre
Angle of Attack
Striking Velocity
HESH and HEP-T
What types of armour will defeat HESH?
Spaced armour
Skirting plate
Grooving
Reactive Armour
Explosive Parameters: Explosives
Define
Define Deflagration
Is a technical term describing subsonic combustion that usually propagates through thermal conductivity (hot burning material heats the next layer of cold material and ignites it).
Explosive Parameters: Explosives
Definition
Define Detonation
Involves a supersonic exothermic front accelerating through a medium that drives a shock front propagating directly in front of it.
Explosive Parameters: Explosives
Definition.
Define both a primary and secondary explosvie
A primary explosive is an explosive substance which is extremely sensitive to stimuli such as heat, friction and/or shock and which requires special care in handling. The probability of development of detonation from the reaction initiated by a mild stimulus is sufficiently adequate or the explosive to be used as the source of the detonation wave in an explosive train.
A secondary explosive is an explosive substance which is relatively insensitive to stimuli such as heat, friction and/or shock. (eDEOP)
Explosive Parameters: Explosive trains
Definition
Define an explosive train
An arrangement used to lead explosive reactions from one place to another (eDEOP).
A sequential arrangement of initiator, intermediary and main charge, eg detonator, booster and main high explosive charge.
Explosive Parameters:
List
What are the requirements for military explosives
Performance - dependent on weapon
Correct sensitivity
Stability
Water resistance
Consistency
Good Thermal behavior (function at varied temps)
Explosive Parameters:
List
Factors influencing explosives are?
Quality of initiating source. Nature of explosive. Mass of explosive. Unit density of explosive. Degree of confinement.
Explosive Parameters:
List
List the 8 ways an explosive can be initiated
Direct heat / Flame
Percussion and stabbing
Friction
Electtrical initaion
Shock waves
EM fields
Laser
Chamical eaction
Explosive Parameters:
Definition
Define VoD
The rate, in metres per second, at which the wave of detonation passes through an explosive substance.
Explosive Parameters:
List
List factors affecting VoD
Density of the Charge
Charge Diameter
Degree of Confinement
Strength of Detonator
Explosive Parameters:
Definition
Define Brisance
The shattering effect of explosives. This cannot be expressed by any single figure.
Explosive Parameters:
Definition
Define FoI
A relative number based on the ability of an explosive to remain insensitive to impact.
Used to indicate if an explosive is safe to store, transport and use.
Used to determine if a high explosive is a primary of secondary explosive.
Explosive Parameters:
List
list the FoI ranges for Highly sens, intermediaries, and Main charges
Highly sensitive;
Figures 20 and below
Used mainly as Initiators
Intermediaries:
Figure 70-100
Main Charges:
Figures greater than 100
Explosive Parameters:
Definition
Define rate of burning
Burning is a series of chemical reactions which take place at or just above the surface of the explosive.
The rate of regression allows the calculation of the burning rate and it is measured on the burning rate index.
The explosives recede layer by layer as the surface is turned to gases and ignited.
Explosive Parameters:
Definition
Define oxygen balance and why its important
The Percentage by Weight of Oxygen, positive or negative remaining after an explosion
When the oxygen balance is neutral then the heat of explosion is optimal.
Any deviation from the perfect oxygen balance will lead to a lower heat of explosion.
