Guns Final Flashcards
What is a weapon
“Any instrument or device used in combat, fighting,
or war to attack someone or defend yourself”
What is a weapon system
“A combination of one or more weapons with all related equipment, materials, services, personnel, and means of delivery and deployment
(if applicable) required for self-sufficiency.
What is safety criticality for a gun system
Weapon systems are designed to cause
destruction to their intended targets only.
Critical failure of these systems may cause injury
or death to human beings.
Defined in terms of: safety, accuracy and control
What are mission critical gun system characteristics
Failure of a weapon system to operate or to damage its intended target may cause significant loss in terms of personnel, equipment, capital and/or defence capabilities of a unit, military, or country
Defined in terms of: reliability, flexibility, speed, simplicity, maintain ability
What is the Fire Control problem
How to hit a moving target in a moving medium on a moving platform with a moving projectile
What are the different reference frames
Stable - the frame is fixed and non-rotating with respect to distant stars, it never moves
Unstable - this frame is fixed to a particular object and moves in relation to that object’s orientation
Different types of coordinate systems and what they’re used for
Spherical - ideal for measuring target parameters as a sensor and weapon systems that rotate around their axes. Two angles and a linear distance
Cylindrical - used by some older guns. Angle of bearing, vertical and horizontal distance
Rectangular - describe target’s range in true North/south, east/west, up/down
What is system alignment and parallax error
Two systems that are not co-located will experience parallax error. Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, measured by angle between two lines
Alignment essential to make sure systems are looking at same object
Convert to same frame of reference using master datum
What are two main categories of ballistics
Exterior - a number of natural phenomenon that tend to cause a weapon in flight to change direction, velocity, or both
Interior - the forces and motion of a projectile as it accelerates inside a gun
What are the forces acting on exterior ballistics
Gravity
Drag - force acts opposite to direction of motion
Wind
Drift
What are the three types of drag
Skin drag - friction on the projectile’s surface as it moves through air
Shape drag - Flow of air creates low pressure zone at base of projectile
Wave drag - Projectile compresses gas in front of it, creates pressure wave
What are the components of wind
Range wind - parallel to projectile’s line of fire
Cross wind- perpendicular to projectile’s line of fire
Detect to engage steps
Detect - determine target exists
Localization - determine target’s exact location
Classification - determine target’s type and probable intent
Tracking - continuously update target’s position through various sensors
Engage - starts when first weapon assigned to engagement plan is activated and end when target has been defeated
Hard kill vs. Soft kill
Hard kill - A weapon that imparts energy to a target in order to cause physical damage. Examples of destructive energy include physical contact (projectile or shrapnel), a pressure wave (explosive force), or directed energy (laser
beams)
Soft kill - Countermeasures that alter the tracking and sensing behavior of an incoming threat to prevent it from tracking its intended target. Examples of interference include active directed EM emissions (jamming) or passive
decoys (chaff, flares).
Total range vs effective range
Total range - minimum and maximum range limits which a weapon can engage a target
Effective range - A portion of the total range in which a weapon system has a PKill above a predetermined threshold for a specific target type
Arcs of fire vs Blind arcs
Arcs of fire - radius of coverage of a given weapon system
Blind arc - Area where weapons cannot fire
AAW Meshed defence
Can’t add pic look at slides
Offensive vs defensive weapons
Offensive - strike at enemy troops, equipment, or infrastructure IOT degrade their combat capability and/or political resolve
Defensive - used to prevent the enemy from striking at our personnel, equipment, or infrastructure IOT protect our combat capability and/or political resolve
Offensive interchangeable with defensive, classification relates to its primary use
Point defence vs. Area defence
Point - designed to protect employing unit from a threat. Can’t defend other units unless close or in line of fire
Area - protect a zone around the employing unit. Every unit in the zone around the employing unit can be defended by the weapon
What is meshed defence
The concept of designing a platform with interlocking and overlapping weapons and sensors ranges and operating arcs to ensure maximum protection against any threat
What is naval gunfire support
Use of naval artillery to provide land support
Muzzle velocity
Speed of projectile the moment it leaves the gun, impacts max range
What is rate of fire
Frequency a weapon can fire or launch its projectiles (rpm)
Cyclical- mechanical rate of fire
Sustained rate - rate weapon can fire in definitely without failing
Round capacity vs ready use
Capacity - Number of rounds available for immediate firing
Ready use - # rounds in the mount ready to use before it needs to be reloaded (40 in 57mm, 120 is capacity)
Load - Use hoist to bring ammo up
Reload - Faster than loading, fire 40 ready use rounds and intermediate mags drop rounds into ready use mag
Accuracy vs precision
Accuracy - hit exactly where it’s aiming at
Precision - constantly hit same target in repeated fires
Aim correction types
Miss distance - Projectile fragments before it comes into contact with target, fragments can disable threat. Max Miss distance for each projectile, must detonate within Miss distance for sufficient prob to kill target
Miss distance indicator - fire at target and MDI targets how much you missed by, adjust for next shot
Spot correction - set fixed point tracked by radar, radar measures where each target passes through that plane to make corrections
Continuous Aim Correction - Measures position of target and in front and behind target, measure position of rounds as they go. Track rounds before and after targets to correct angles to fire at
What is slew rate
Rate gun move in bearing and elevation
Safety firing arcs
Bearing and elevation that must be clear of any vessels to prevent accidental hit NAVORD 4995-0
Where projectile can enter when fired
Conservative to accommodate for misalignment
Basic block diagram label
Look up answer
Gun structure
Barrel, breach, feed and cooling system
Recoil and laying system part of mounting arrangement
Loading system connected to mounting arrangement, exists below deck
Gun barrel - Allows gases to expand to launch projectile, restricts the expansion, stability to projectile, imparts spin (rifling). Made up of muzzle (where projectile exits) bore (rifling) chamber (where ammunition sits before firing, wider to accommodate cartridge)
Within barrel secondary components - chase (bulk of barrel) slide cylinder (retract as barrel recoils) housing (rest of components are)
Remember breach types (screw and slide)
Breach types, extractor
Screw - 8 inch or larger, bagged propellant
Sliding block - sliding element blocks off breech opening
Way that breach block works (diagram)
Breech extractors - breech locked in place by extractors when no ammo in. When round is in, engages extractor as it enters, unlocks breech to slide into closed position. After fired, breech is pulled back which pulls retractor back which pulls empty case out of chamber. Breech goes back into locked position until next round is put in chamber
Recoil system
Absorb recoil energy, return gun to firing position.
Laying system
Two sub-systems - training and elevating (horizontal/vertical plane)
Feed system
Passes immediate use ammo to firing point.
Loading system
Storage, transfer to gun
Mounting arrangement
How gun is attached to whatever platform it’s on
Must:
Support gun body
Elevate and train gun body
Mount components
Laying system
Recoil system
Slide
Trunnions
Carriage
Stand
Cupola
(LABEL)
Ammo types
Bag -
Case type - separate (primer and propelling charge in cartridge case, projectile is separate unit, rammed together before firing) and fixed (all in one)
Self propelled -
Cartridge case - propellant, primer, wad, lead foil, distance piece, base (interface to fire, voltage or percussion hit)
Burn patterns (DRAW)
Dégressive - slows down as it burns so surface area decreases as it burns (short barrel length, no steady pressure)
Neutral - Surface area stays the same through burn
Progressive - surface area increases as it burns (long barrel, increasing pressure), burns faster as time passes
Detonation
Deflagration- slower than speed of sound
Detonation - faster than speed of sound
Explosive categories:
Primary - small amount of heat initiates, sensitive materials
Secondary/tertiary -
Explosive train (DIAGRAM)
What numbers represent
1 - how you detect target
2 - detonator
3 & 4 - safe arming device
5 - detonator
6 - booster
7 - main charge
Projectile components
Ogive
Bourrelet
Body
Rotating band
Base
LABEL
Types of fuses
Time
Impact/contact
Proximity
Checks that sage & arming device passes before initializing explosive train
Wet
Pressure
Distance from ship
Proximity
All designed to have min 2 safety devices
Tests and trials
INO - Inspection of Naval Ordnance, make sure all components installed correctly and free from defects, avoid catastrophic failure
Full INO- ship request, 6 months, after commission, fired for x rounds, after refit, as directed by risk management organization (e.g FTA)
Opérations tests:
Daily EHM (BIT test)
Pre/post firing
Mount motion
Alignment: common reference point for sensor/gun combo
