Delivery Systems Flashcards
1
Q
When defining a target what characteristics do you look for?
A
Size, Criticality, Vulnerability, expected doctrine, velocity, manoeuvrability, exposure time, raid rate, raid interval, raid composition
2
Q
When looking at detectability what are the characteristics do you look for?
A
Reflectivity (RCS, Retro-Reflectivity), Emmissivity (thermal, optical, acoustic, RF), Counter Measures (DAS, Situational awareness, obscurants, decoys, grenades)
3
Q
When looking at the target environment what characteristics are there?
A
Location (Where in the world, range) Terrain (Urban, forestation, Tundra, ice/snow, Mountain, sea state), Clutter (thermal, acoustic, radar) Contrast against environment, GPS or service denied environment.
4
Q
What Does Fkill mean?
A
Fire power kill.
5
Q
What does Mkill mean?
A
Mobility kill.
6
Q
What does Pkill mean?
A
Personal Kill or incapacitated.
7
Q
What does KKill mean?
A
Catastrophic kill, complete loss of the target.
8
Q
What does CKill mean?
A
Comms kill.
9
Q
What does AKill mean?
A
Acquisition system kill.
10
Q
What is the definition of Accuracy?
A
The ability of a weapon system to place the mean point of impact (MPI) of a series of rounds on a given aiming point.
11
Q
What is the definition of Consistency/precision?
A
The degree of dispersion of that series of rounds about the MPI. (the ability to repeatedly hit the same point)
12
Q
What is Circular Error Probable (CEP)?
A
It is used to quantify spread in horizontal and vertical directions which is defined here as the radius of a circle centred at the aimpoint which is probabilistically impacted by 50% of the projectiles. It is often assumed that the impact follow a gaussian distribution centered at the aimpoint.
13
Q
How do achieve hitting a target?
A
Brute force and ballistics, assistance, guidance
14
Q
What are the stages of the engagement sequence?
A
Find, fix, track, target, engage, assess
15
Q
What characteristics effect the engagement sequence?
A
Detect, Recognise, Identify, compute, engage, assess
16
Q
What things are used as part of the effector? (to defeat)
A
Penetration, fragmentation, follow through, other (smoke, illumination, less lethal, suppression)
17
Q
What is the basic delivery requirements of a unguided munition?
A
Sufficient speed to reach the target, capable of inflicting a degree of damage, capable of being launched, must be safe to handle
18
Q
An unguided weapon is made up of a fuze and warhead, but in a powered unguided weapon what additional component is there?
A
The rocket motor.
19
Q
What things do you need for a gun launched system?
A
propellant, gun barrel, super structure, vehicle/ carriage/mount/soldier
20
Q
What support infrastructure do you need to support Guns?
A
Transport gun and ammo, gun crew, alignment, forward observers, ballistic computer, fuze setters, C4 ISTAR, wear, degradation, maintenance, storage, operator training, manuals and paper work, ammo productio, ergonomics.
21
Q
What are 3 types of projectiles? (Cusp of change)
A
Traditional projectile, projectile with guidance, projectile with guidance and glide.
22
Q
What are the different types of target sets?
A
Personnel (Unarmoured, body armour), Soft skinned (buildings, vehicles, aircraft), Armoured (Vehicles, protected buildings, naval), Other (Suppression, less lethal, courageous restraint), Station or moving?
23
Q
What are the key parts of a gun?
A
Trails, pivot, saddle, cradle, trunnion, breech, barrel
24
Q
What does the trunnion do?
A
It hold the cradle and pivots.
25
Why do guns have long thin barrels?
To make them lightweight, with a short as possible barrel. Mainly to reduce stresses on projectile as well as to simplify propellant design. They are also designed this way because it enables weight optimisation.
26
Can barrels be short and thick?
yes
27
What are the benefits to a short thick barrel?
Long thin barrels can reduce projectile stress during launch.
28
What are the benefits of long thin barrels?
Reduce weight and simplify propellant design.
29
When E= Energy at muzzle = LxF what is F?
E= Energy at muzzle
L=Length of barrel
F= Force on projectile
30
What must the energy in a gun barrel be sufficient to do?
Reach target, overcome air resistance, deliver energy to target.
31
Force on a projectile is worked out how?
Pressure x area
32
Stress x Area = ?
Force
33
How you work out area in a gun barrel?
Pie/4 x Diameter ^2
34
What is a way of working out Energy?
Mass/2 x stress/density
35
How do you work out the mass a gun barrel needs to be?
Pie x Diameter x t (maybe wall thickness, check later) x density
36
What is autofrettage?
Compressing the inner gun barrel to get better results from the gun barrel.
37
What is the use of the forward obturation?
Sealing around the projectile.
38
What is the use of the reward obturation?
Sealing around the breech.
39
Why do we use a forward obturation?
it is a soft driving band that engraves the rifling.
40
What is approximately the force on the breech?
The force on the breech is approximately the same as the force on the projectile hence the gun is forced backwards.
41
How do you stop the gun do an x games trie flip backflip no scope 360 under tuck virgin spring flip?
1. Let it slide backwards
2.place a spring between barrel and trunnions
3. using a buffer by churning oil through a piston.
42
What is a moment?
Force x distance (ben said so and cba to fact check him)
43
what is the use of a muzzle brake?
other then making the gun look ally, it deflects the propellant gasses from going forward.
44
What does C^4 I mean and do?
Integrated fire (IF) control system helps control the gun
45
Small arms where is the recoil system?
the firer is the recoil system
46
Why is missile control and guidance necessary?
High single shot kill probability, not enough to point and shoot, unguided projectiles have issues such as random dispersion at launch.
47
What are the issues of unguided projectiles?
Random dispersion at launch, deflection of path by aerodynamic and other disturbances, target movement
48
What are the requirements for guided weapons?
Sufficient speed advantage to intercept or catch its target, a manoeuvrability advantage, capable of inflicting a satisfactory degree of damage, be launched satisfactory, safe to handle, an increased need to have multi-role capability as well as be modular, reuse of existing sub systems and low cost.
49
What are some types of technologies used in Guided weapons?
Propulsion, aerodynamics and structures, radar STA and homing, EO/IR detection tracking seekers and counter measures, control and guidance methods, laser principles and applications, warheads
50
what are some applications and systems of guided weapons?
Surface to surface, SAMs, ASM, ATGW, DEW systems, Weaponised UAVs, Hypersonic vehicles
51
What does raid mean in target context?
The amount, type and how and when the targets come, for example if you have 15 Lancet drones but only 10 SAMs this then causes a problem.
52
What are the trends in modern warfare with guided weapons?
Improved fire power effect with technological advances, use few weapons at a reduced cost logistics and manpower.
53
What factors drive precision attack philosophy?
Politics, increased media exposure, rules of engagement, need to minimise collateral damage and friendly fire engagements.
54
What technical advances aid precision attack philosophy?
Low cost and miniaturised advances, GPS inertial navigation systems, control and guidance, network enabled capability, material and warheads, aerodynamics and propulsion, radar and imaging IR seekers
55
What types of Non missile guided weapons are there?
Guided artillery, guided tank munitions, artillery launched rockets, guided tank munitions
56
What do Directed Energy Weapons do?
Near instantaneous travel duration and relatively long time for effect
57
what are the effect profile of a guided missile?
Relatively long travel duration and near instantaneous effect.
58
What are some examples of directed energy weapons?
Active denial systems, lasers, dazzlers, plasma weapons, sonic weapons
59
What is the unofficial definition of a guided weapon?
unmanned self propelled veh, which delivers a lethal package, like my dick.
60
What makes up a guided weapon?
Seeker, fuze, Warhead, Control and guidance unit, power supply, rocket motors, actuators, control
61
What makes up the guided weapon system?
STA, Weapon, Target characteristics and physical environment, training and logisitcs
62
What makes up the missile systems?
Payload (warhead, fuze, telemetry), airframe, propulsion system, Guidance and control (airborne) Power supply
63
What makes up the base system of a guided weapon?
Launching system, guidance and control (ground base), command/decision system, communication system, STA sensors.
64
What are the six types of ballistics?
Internal, intermediate, external, terminal, wound and explosive fragmentation
65
What is the definition of trajectory?
The general downward curving flight path of a projectile which is taken by the projectiles centre of mass.
66
What is the definition of stability?
Keeping the projectile pointing in the right direction
67
What is the definition of drag?
Loss of velocity in flight
68
Why can you either reduce or increase the angle away from 45 degrees by the same angle to get the same range?
because 45 gives the maximum angle for range when air resistance is not taken into account so any movement away from that reduces the range.
69
How do you work out the max range in vacuo?
Max Range=U^2/g where U is the launch velocity and g is the acceleration due to gravity (9.81 ms^-2)
70
How do you work out the range in vacuo?
Range = sin(2θ)Rmax where θ is angle of elevation.
71
Does air resistance reduce or increase effect of drag?
Reduce
72
What are the 3 stages a projectile goes through during its trajectories?
Supersonic shortly after firing, Transonic before slowing down to subsonic before reaching its max height and coming back down and if time allows it will become transonic again.
73
What are the effects of air resistance on a trajectory?
Projectile arrives with less velocity than at launch, maximum range trajectory is not 45 degrees
74
Benefits of using low trajectory?
Simplicity of aiming, short time of flight, avoids effect of weather
75
Benefits of firing on high trajectory?
Obstacles in the way, warhead effect, absorbing reaction of recoil
76
If you are firing at a target above you is the range increased or decreased?
Decreased
77
If you are firing at a target below you is the range increased or decreased?
Increased but to a point where the round is falling vertically downwards
78
What are the effects on trajectory?
Drag, Gravity, wind drift, equilibrium yaw, magnus effect, earth rotation
79
Does adding a point to your projectile benefit more then adding thins?
No Thins benefit a projectile more as they stop the projectile becoming unstable, the best projectile has both thins and a point.
80
What happens to air as a projectile moves through it?
It disrupts the air as it moves through it, the more aerodynamic the projectile the less it disrupts the air.
81
When the velocity of air increases what happens to the pressure?
The pressure reduces
82
when the pressure increases what happens to air velocity?
The velocity reduces.
83
With pressure on an aerofoil if there is no lines in either direction what is happening with pressure?
The pressure is atmospheric, this is found at the front of a wing as the wind hits the wing.
84
At the flow over an aerofoil where is velocity of the air the most?
at where the wind meets the wing where the pressure is zero (Atmospheric pressure) the velocity is the highest
85
If you have a piping system, what is the kg of what you put into the system when it comes out the other end?
the kg of stuff you put in one end must be the same as what comes out the other end, the mass is the same
86
What 3 things happen when you decrease velocity of air?
Pressure increases, density increases, temperature increases
87
What 3 things happen when velocity of air increases?
Pressure decreases, density decreases, temperature decreases
88
As air moves into an object what happens to the KE of air?
The Kinetic energy is converted into an increase of pressure, shown by the formula 1/2pressure x velocity^2
89
Which direction is Yaw?
It can be either direction, either Yaw up and Yaw down or any angle you'd like. Any angle of the trajectory is yaw.
90
What does Yaw cause?
The Yaw causes a lift force perpendicular to the velocity.
91
Where does the force due to gravity act?
They act on the centre of mass
92
where do objects rotate from?
There centre of gravity.
93
What happens when the centre of pressure is ahead of the centre of mass?
An overturning moment is generated
94
What does over turning moment cause?
loss of stability, this is important as if the fuze dose not hit the ground first it may not function properly
95
If anyone reaches this far, i have lost the will to live.
the over turning moment is 1/2 pressure velocity^2 x area x diameter x overturning moment slope coefficient x ???
96
what is in all missiles?
Some form of thermochemical jet propulsion, provided by a rocket or an air breathing engine. A fuel and an oxidiser are also needed in either case.
97
What is a blip or eject motor?
Used to soft launch a missile away from the launch point or operator.
98
What is a boost motor?
Used to quickly accelerate the missile up to its desired velocity
99
What is a sustain motor?
used to maintain flight speed to the terminal phase
100
What is a terminal boost motor?
sometime used to accelerate the missile for higher terminal velocity target engagement
101
What is a thrust vector motor?
Used to improve a missiles lateral manoeuvrability
102
What does jet propulsion rely on?
Jet propulsion relies on the reaction force produced by discharge of matter from the propelled body, normally in the form of a fluid jet
103
What is thrust dependent on?
Mass flow rate and jet velocity, an increase in either will increase the thrust produced.
104
What temperatures do gases in thrust get to?
between 2500-4100 Degrees C
105
What is used to make sure the steel on missile doesnt melt during the propellant burning?
Cooling is used or insulating the surfaces that are exposed to hot gases.
106
What happens in liquid propellant rockets?
The fuel and oxidant are tanked separately and delivered to the combustion chamber at specific rates and pressures.
107
What are the 3 main types of liquid propellant?
Petroleum + oxidiser, Cryogenic, hypergolic
108
What are the disadvantages of using liquid propellants?
Increased complications, formidable storage problems, much more costly, reduced reliability
109
What are the 4 components of solid propellant rockets?
Motor case, nozzle, solid propellant charge, igniter
110
What is solid propellant rockets charge made up of?
fuel and oxidizer, usually either of a double base or composite construction
111
What nozzle is used for a solid propellant?
Convergent divergent nozzle which vents hot gases to provide a high speed super sonic propulsion jet
112
What are some features of solid rocket features
high propellant density, long lasting chemical stability, readily available, lower specific impulses, difficult to vary thrust output on demand
113
When does maximum thrust occur?
Maximum thrust occurs in the fully expanded condition
114
What is specific impulse?
The ratio of thrust/propellant mass flow rate is used to define a rockets specific impulse, this is a good measure of the overall performance of a rocket motor
115
How can you obtain the total impulse?
A high F but short boost application or a low F but long sustainer application
116
What does the thrust coefficient depend on?
Its value depends primarily on pressure ratio so it is a good indicator of the nozzle performance
117
What are internal ballistics in rocket propellants?
They are the study of the combustion process of a solid propellant rocket motor. Fuck knows what this means im lost
118
What is propellant burn rate empirically determined from?
the burning of small slabs under standard test conditions
119
What is the burn rate of a solid propellant primarily a function of?
the propellant composition, the combustion chamber conditions which includes the pressure acting on the propellant and temperature
120
What is equilibrium condition?
A steady state condition is reached when two mass flow rates are equal
121
What might you add to ballistics to reduce its sensitivity and improve stability.
Lead salicylate, lead stearate, know as platonisation
122
What is erosive burning?
Very high velocities are produced towards the nozzle region this affects heat transfer rates and locally increases burn rate - this is known as erosive burning
123
What is the thrust profile of progressive grain?
A burn during which thrust pressure and burning area all increased with time
124
What is the thrust profile of a neutral grain?
a burn during which thrust pressure and burning area remain constant, the normal requirement
125
What is the thrust profile of a regressive grain type?
A burn during which thrust pressure and burning all decrease with time
126
What are the characteristics a cigarette burner?
long burn time big CG change
127
what is often used for sustainer operating modes?
End burning charges
128
In the exam what will one of the questions be?
You are given a particular missile then asked what type of proportion is best used.
129
What is an air breather?
the oxidiser is used by in taking air from the atmosphere.
130
What are the types of air breathers?
Turbofan, turbo jet, ram jet, scram jet
131
When going through these can someone remind me to look at the GW propulsion stuff, i lost the will to live on air breathers side of it so its light on the ground
Boo
132
Where do aerodynamic force act upon?
On the centre of pressure
133
How do you work out overturning moment?
Side force x distance of centre of pressure away from centre of mass
134
What are the two methods of stabilisation?
Fin Stabilisation and spin stabilisation
135
What happens when the centre of pressure is ahead of the centre of mass when a projectile is yawed off a horizontal trajectory?
The projectile becomes unstable
136
What happens when the centre of mass is ahead of the centre of pressure when a projectile is yawed off a horizontal trajectory?
the projectile is stable, this can be achieved through the addition of fins to the projectile
137
What does Yaw drag cause?
Oscillations
138
What can you do to stabilise a projectile when the centre of pressure is in front of the centre of mass?
Use spin stabilisation
139
If the density of air increases like on a cold day, is the projectile more or less stable?
Less stable, and even more less stable in water or tissue. Less stable? unstabler?
140
where does fin stabilisation move the centre of pressure?
It moves it behind the the centre of mass so that yawing opposed by moment
141
how do you achieve spin stabilisation?
Spin the projectile using the rifling within the barrel
142
What happens when you apply to much spin to a projectile?
The projectile is over stabilised so reduces the adjustment of the curve of the trajectory in flight.
143
How much air lies along the path of a 155mm shell flying around 30km
500 Kg worth of air
144
What are the sources of drag?
Pressure drag, yaw drag, skin friction, excrescence drag
145
What is the drag coefficient of a flat faced object?
1.0
146
How do you work out the Mach Number?
Speed of projectile/ ambient speed of sound.The speed of sound at sea level is around 340 m/s
147
What is pressure drag caused by?
Pressure drag is due to differences between pressure on nose and base and due to shock waves
148
Does adding boat tail reduce or increase drag?
Reduces drag
149
Does a base bleed reduce or increase base pressure?
Base bleed increases base pressure
150
Does a sharp nose reduce or increase wave drag?
It reduces wave drag
151
What causes pressure drag?
It is due to pressure on nose and base and due to shock waves
152
What causes yaw drag?
Due to failure to point along the trajectory
153
What causes skin friction?
Due to viscosity of air
154
What causes excrescence drag?
Due to protuberances on projectile
155
Who created the modern Torpedo?
Robert whitehead - an english man in the 1860s
156
What are the major design drivers of a torpedo?
Major diameter/ length restrictions by platform, harsh operating environments (1-100 atmosphere pressure range, resultant heavy weight structure, freezing air and water conditions, corrosive salt sea water), seeking a quiet target in a noisy background environment, for acoustic sensors systems sound is slow and uncertain ray paths
157
For the exam look at comparison of underwater and air weapons design parameters slide
it will come up
158
whats the basic make up of a torpedo?
Homing sensor, warhead, guidance and control, battery, motor and propulsion
159
What are the two torpedo classifications?
Lightweight (LWT) and Heavy Weight (HWT)
160
Examples of modern LWT torpedos?
APR-3E, Yu-7 and Yu-11, Mk 54 MAKO, Stingray, MU90 Impact
161
Where does the buoyancy force act upon on a torpedo?
It acts through the centre of buoyancy
162
If the buoyancy force is not enough to lift a torpedo what must be done to stop it sinking?
In the design phase you must account for this force and add lift if the buoyancy does not lift the torpedo.
163
What are the two discharge options on a torpedo?
Positive - store expelled by an energy source within the sub
Swim out under the torpedoes own power
164
what is a common tendency when discharging a torpedo?
The torpedo has a tendency to nose up which can be overcome by an increase in speed or tail effectiveness
165
What is the current system of positive discharge?
Use pressure balance systems, are not depth dependent
166
What is a general make up of a discharge system?
Bow cap assembly, bow shutter, tubes 1-4, inner doors, control console
167
What is the rough exit speed of a torpedo in still water?
12 m/s
168
What is in terms of torpedoes is hang up?
At high launch submarine speeds the velocity between torpedo and submarine is zero and cannot be launch
169
What are some common battery types in torpedoes?
Lead acid, nickle cadmium, magnesium silver chloride, zinc silver oxide, aluminum silver oxide
170
Missed stuff on torpedo guidance onwards please make cards
Boo
171
need to do cards on propulsion of torpedos
172
How fast do you need to be going roughly to be hyper sonic
above mach 5
173
What does ISA stand for and what is it used for?
International standard atmosphere is used as a comparative performance standard
174
What is defined as the edge of the atmosphere?
above 100km of sea level
175
what is lift?
The aerodynamic force perpendicular to the flight direction
176
What is drag?
The aerodynamic force parallel to the flight direction, thrust is used to overcome the drag force
177
Is more drag ever good?
Sometimes but rarely
178
Probably need more on aerodynamics
179
i have stopped listening for the last lesson on tuesday, playing geoguesser instead
Someone remind me to make the cards
180
How is guidance achieved?
Autopilots, Guidance techniques
181
What are the elements of a guidance system?
Target data and missile data feed into the guidance computer then this produces steering orders into the missile and missile response, this is made up of target tracker, missile tracker, guidance computer, command link, and missile autopilot
182
What are the functions of guidance equipment?
Measure the target and missile relative positions and velocity
Calculate the appropriate interception trajectory
Determine the error in the present missile trajectory and to determine any corrections required
Produce inputs to the missile autopilot to reduce trajectory errors to zero
183
What are the three phases of flight in terms of guidance?
Boost phase, mid course guidance, terminal guidance
184
What are guidance design characteristics?
Ground based targets (moving or static), aerial target, where in the world, how much payload, penetration, target most vulnerable area
185
What are some guidance classification?
Guidance onto location in space (GOLIS), Guidance onto target (GOT)`
186
What are the four primary mechanism used to steer a missile?
Normal force due to angle of attack, moment due to angle of attack, normal force due to control deflection, moment due to control deflection
187
What makes up the miniature silicon accelerometer?
Machined silicon, integral electronics, integral force feedback, integral temperature compensation
188
How is velocity calculated using acceleration in a guidance system?
Acceleration is measured as a voltage output that is integrated electronically to calculate velocity. If then velocity is integrated then a voltage equal to change in position is obtained.
189
In guidance systems how is angle measured?
Using gyroscopic effects to infer rotation information.
190
In mechanical gyros, what bias can occur?
G-independent bias, g-dependent acceleration bias, g^2-dependent anisoelastic bias
191
What things do Inertial navigation systems need to be known to work properly?
Initial conditions need to be know accurately, otherwise the results are subject to drift, measurement noise, scale factor error and bias.
192
How does compass heading help navigation systems?
The earths magnetic field provides information about yaw based on the location on the earth and the direction to the earths magnetic north
193
What are some types of navigation systems?
Floated rate gyroscope, rate integrating gyroscopes, Ring laser gyroscope, fibre optic gyroscope, vibratory gyroscopes, compass heading, gyrocompass (north seeking gyro), GPS, Pitot-static sensors
194
What is the difference between control and guidance?
Guidance is concerned with identifying where the target is and formulating instructions to the missile to cause it to meet up with the target, where as control is concerned with with how to make the missile airframe respond to those guidance instructions. Both employ feedback to achieve their objectives.
195
What are the benefits of closed loop systems?
Reduce the effect of external loading, reduce the effect of internal parameter changes, improve the speed of the response, improve accuracy.
196
How do control surface actuators work?
Motors provide torque to rotate the control surface on its hinge given an input voltage. Sensors measure physical parameters on the hinge to make sure correct angle is achieved.
197
What process does a missile need in order to change direction in flight?
It changes its aerodynamics
198
What control inputs can you use to change angles of attack in a missile?
aerodynamics, lateral thrust, aft thrust vectoring
199
What are some characteristics of tail control in missiles?
Most common, actuation units fits around blast pipe, low hinge moments and actuator loads, high static stability low maneouvrability, required force initially in opposite direction, cabling required form auto pilot past rocket motor
200
What are characteristics of canard control?
Latax in correct direction giving more rapid response, packaging benefits from proximity to autopilot (less internal cabling) low static stability, high manoeuvrability, large hinge moment and actuator loads, poor roll control, may need to decouple tail in roll
201
What are some characteristics of moving wing control?
Small incidence range, suitable where intake efficiency is critical, large actuator loads, very careful design required
202
What are some types of control?
tail, canard, moving wing, lateral thruster (Bonker), TVC
203
what are the Two high level control policies that are used?
Skid to turn (STT), Bank to turn (BTT)
204
What are characteristics of cartesian control?
symmetrical missile, simplifies design, most common method, gives fastest missile dynamic response
205
What are some polar control characteristics?
twist and steer requires only one pair of control surfaces but commands implemented sequentially, four separate surfaces gives full independent roll control, allows for the maintenance of air flow intakes
206
What must a firing mechanism be able to do on very basic terms in small arms?
Fire the weapon, stop firing, allow safe handling of the weapon
207
what very basic mechanism do you need to fire a small arms munition?
Flash hole, anvil, primer, firing pin, breech block
208
In very basic automatic small arms what mechanisms do you need?
flash hole, anvil, primer, firing pin, breech block, firing spring, hammer
209
What different types of firing mechanism are there in small arms?
hammer firing mechanism, striker firing mechanism, firing mechanism using the spring return
210
What mechanisms and components are most effected by stress in small arms?
Hammer impacting the primer, striker hitting the primer, gases impacting on the firing pin via gas pressure, breech and hammer making contact, hammer hitting the firing pin.
211
Whats an issue when dry firing small arm weapons?
Stress on the hammer due to lack of cushioning by the primer.
212
What is the role of the trigger in small arms?
the trigger mechanisms star and stop weapon firing.
213
if built incorrectly what can trigger mechanisms affect?
It can affect accuracy, there is minimum trigger pull built in for safety
214
What is the minimum trigger pull in military pistols?
It is usually 18N for pistols, and for automatic rifles 25N
215
What do extractors do in small arms?
hey recomve the empty case or unfire cartridge from the chamber. they do this by using an extractor fitted to the breech block
216
Need to make cards on hydrodynamics, im far to tired to do this now
beers beers beers
217
How is target and background signature produced?
The target and background signature is produced by the reflection of photons (visible and near IR) 400nm and the emission of photons in the mid and far IR.
218
What is an ideal type of radiator?
The ideal radiator is called a black body, this is defined as having radiation efficiency of 1, any thing less than 1 efficiency is called a grey body
219
Where must light be collected from?
Light must be collected from the scene
220
Why do we need to collect light and what use does this have?
To form an image, maximise a signal on a detector
221
Do all waves undergo diffraction?
Yes
222
What does the nature of waves when going through an aperture found to depend upon?
The nature of the wave beyond the aperture is found to depend upon the width of the aperture relative to the wavelength.
223
Does pixel size impact the resolution of our system?
Yes
224
What is a detector in terms of light?
an array of pixels
225
What limits the minimum pixel size that can be used in an EO system?
Diffraction.
226
Lander max is what?
The most intense wavelength worked out by 2898/T ( measured in Kelvin) in microns
227
What is the resolution limit given by?
resolution limit is given by the last bar target that is recognisable
228
If something if emissive can it be reflective?
It is unlikely to be reflective if it is emissive
229
what is the refractive index
It is the speed of light in vacuum / speed of light in what ever it is going through
230
What are the criteria of the Johnson rules?
Resolution capability measured using bar targets with appropriate contrast, real targets then used, range changed until 50% of observers could detect images, angle subtended gives number of cycles per minimum object dimension
231
3 stages of surveillance criteria?
Detection, recognition, identification
232
What are characteristics of infrared detectors?
Detect long wavelengths, energy is small, which means small excitation of the electron in the detector, some electrons in the detector material would already be slightly excited if the detector material was at room temperature, cooling the detector ensures the only excited electrons are those excited by the photons
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What does a laser rely on to emit light?
A laser relies on stimulated emission
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What does laser stand for?
light amplification by stimulated emission of radiation
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how do you work out the recognition using pixels?
you need at least 16 pixels across the minimum diameter to identify an object 50% of the time
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second half of lasers onwards i stopped listening
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Thursday afternoon is a write off need to make notes
BOO
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What are the characteristics of a blow back operation?
Breech not locked to barrel, cartridge case acts as a piston to drive the breech block rearwards, return spring and inertia of breech block resists breech opening forces
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what are the advantages of Advanced primer ignition?
You can increase chamber pressures, or you can reduce the size of the breech block
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What are the advantages of blow back operation?
Simple robust design, no complicated locking components, reliability
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What are the disadvantages of blow back operation?
Heavy breech block, relatively low rate of fire, shoulderless parallel case required, only suitable for low pressure ammunition
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What are the advantages of long recoil operation?
Light weight design, barrel and breech locked during firing, low recoil forces, low gas pressure when breech is opened, light weight breech block
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what are the disadvantages of long recoil operation?
Long receiver, low rate of fire, large and expensive barrel bearings, large changes in CofG when firing
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How does long recoil system work?
cartridge is loaded, weapon is fired recoil goes rewards, barrel unlocks from breech before returning to forward position bring a cartridge with it from chamber, new round fed into the front of the breech being chambered by forward moving breech block, barrel returns locking back into the breech
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What is the process of short recoil system?
Barrel is locked to breech with the cartridge in chamber, the weapon is then fired with the barrel and breech locked and recoil going rearwards, barrel unlocks from breech and breech accelerated rearwards, cartridge pulled from case, barrel is halted and then returned to forward position, cartridge is the ejected, round is feed in front of the breech and then chambered by the forward moving breech block
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Whats the advantanges of short recoil operation?
high rate of fire, barrel and breech locked during firing, light weight breech block,
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what are the disadvantages of short recoil operation?
long receiver, complex design, large and expensive barrel bearings
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How does a gas operation system work?
Breech block is released, cartridge is chambered, breech block is locked to barrel, weapon is fired gas is bled from barrel port, breech is unlocked and pushed to the rear, cartridge case is extracted, fresh round is fed in front of breech block weapon is ready to fire the next round
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What are the advantages of gas operation system?
High rate of fire, barrel and breech locked during firing, operate with range of gas pressure,
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What are the disadvantages of gas operation system?
Long receiver, complex design, high thermal shock loads on gas drive, fouling of operating mechanism by proellant gases
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What is locked blow back?
Same as gas operation but breech block is pushed to the rear by blow back operation
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What happens in revolver gas operation systems?
Round in chamber, partially chambered rounds, gun is fired, gas pressure pushes slide cam rearwards. drum indexes half way, previous case extracted, belt fed for next round, spring returns slide cam forward, drum indexes half way, next round fully chambered, two rounds partially chambered
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What is the advantages of of revolver gas operation?
high rate of fire, compact design due to fixed breech, light weight design
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What are the disadvantages of revolver gas operation?
High barrel wear, large eccentric inertia forces, external power source require for loading, susceptible to cook off
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What are the advantages of gatling operation system?
Very high fire rate, light weight design for rate of fire, cannon is simple design, low barrel heating and barrel wear
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What are the disadvantages of gatling operation system?
Requires large external power source, feed mechanism is large and complex, requires large quantities of ammunition, relatively large dispersion, shift in MPI during firing
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What are the advantages of salvo firing cannon system?
Very high rates of fire, low dispersion, cannon is of simple design, low barrel heating and barrel wear
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What are the disadvantages of salvo firing cannon?
Requires large external power source, heavy breech block
259
What are the advantages of chain gun operation system?
Light weight compact design, variable RoF, low gas pressure when breech is opened, simple mechanical design
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What are the disadvantages of chain gun operation system?
requires external power source, delay of tow cartridges when changing ammunition natures, high RoF not possible with hang fire protection
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What are the advantages of Drum cam operation system?
Light weight compact design, variable RoF, low gas pressure when breech is opened, simple mechanical design,
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What are the disadvantages of Drum cam operation?
Require external power source, ejection takes place in two places, high RoF not possible with hang fire protection
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Is a bolt action system an external power method of operation system?
yes, uses human power which is external to the weapon system.
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What are the advantages of a CTA gun operation system?
Simple mechanical design, parallel case allows push through ejection, parallel case gives high packing efficiency, feed through hollow trunnions simplifies gun operation and reduces swept volume, light weight compact design
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What are the disadvantages of a CTA gun operation system?
Complex and expensive cartridge case,front of rotating breech need to be obturated, side feed and ejection requires and additional turret side space, CTA design limits ammunition design, CTA design prvents gunner from checking the barrel is clear.
266
whats the two ways you can make a gun smaller without shrinking the diameter ammunition?
Shrink the length of the ammo, or reduce the size of the weapon system
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