Ballistics Flashcards
Define ballistics
The scientific study of the motion of projectiles.
What are the 4 types of ballistics
Interior (Internal)
Intermediate
External
Terminal
What is internal ballistics
The scientific study of the operating process within the gun from the moment that the propellant is ignited until the projectile leaves the barrel
What are the objectives (goals) of internal ballistics?
Launch the projectile safely
Consistent performance between shots
Achieve the highest possible muzzle velocity
What is the all burn point?
Where all the propellant has been consumed
What is explosion heat (Qex)?
The amount oh heat liberated in the combustion of 1kg of propellant
Define Pioberts Law
The surface of a burning propellant recedes layer by layer in a direction normal to the surface.
What is intermediate ballistics?
The study of the transition from internal to external ballistics that occurs in the vicinity of the muzzle
What are the 2 parts of bottle shock?
Barrel shock - sides
Mach disc - front
What are the types of flash?
Pre-flash
Primary flash
Muzzle glow
Intermediate flash
Secondary flash
What are the three main ways to minimize muzzle flash?
Muzzle devices ( flash suppressors)
Type of propellant
Propellant additives
What are the 3 main reasons for muzzle devices?
Reduce recoil
Suppress flash
Decrease report
What are the 3 types of silencers?
Blast absorption
Blast dissipation
Blast containment and controlled release
What are the properties of a projectile?
Mass
Calibre
Nose Shape
Spin Rate
What are the properties of the atmosphere
Air Density
Temperature
Pressure
What is trajectory?
The path taken by the C of G of the projectile
What is drag co-efficient? (Cd)
Drag coefficient (C d ) quantifies the drag of an
object through a fluid (Air or Water).
What is yaw?
Angle between axis of projectile and that of the velocity vector or trajectory.
What are the characteristics of propellants ?
Burning Rates
Force Constant
Form Function
Pressure Index
Co Volume
Ballistic Size
Remember 4
What are the six areas of distribution of energy when the gun is fired
Projectile, translational and rotation
Heat in the gas
Gun recoil
Driving band engraving and friction of the bore
Unhurt charge and gases
Heat in the gun
What are the four phases of internal ballistics.
Charge ignition
Combustion prior to projectile motion
Combustion up to the all burnt point
Gas flow and projectile motion after all burnt point to muzzle.
How can the round to round regularity of muzzle velocity be improved
If burning finishes while the shell is still well back in the bore.
Increase pressure
Increase temperature
The muzzle gas flow field during firing consists of what two phases?
The precursor blast field that proceeds the projectile exit from the muzzle
The main blast field that follows as high pressure propellant gases are ejected into the air
What is a bore evacuator?
It prevents propellant fumes from entering crew compartments.
Works by creating pressure diffentials during and after firing
High pressure propellant gases are stored in the evacuator as the round passes through the barrel.as the round exits the muzzle, the high pressure gases flow out the muzzle. This may increase the secondary flash
What are the four drag forces?
Skin friction
Pressure drag
For body drag
Excrescence drag
Define ballistic co-efficient.
The measure of a projectiles ability to overcome drag
What are two way of reducing the effect of base drag?
Boat tailing: Below the speed of sound skin friction and base drag are the principle causes of friction. To reduce base drag a stream line tail is added to the projectile.
Base bleed: A practical method of reducing drag, especially for larger projectiles is base bleed.
What forces act on a projectile?
Drag
Pressure
Yaw
Gravity
Velocity
Roll
How do most flash suppression devices reduce flash?
Break up the barrel shock
Mach disc
What can you use to reduce blast in small calibre weapons like pistols?
Silencers
Burning characteristics of propellant granule
Ballistic size
Form function
What is muzzle press
Peak over pressure at the mizzle upon breakage of the projectile bore seal
What are the 4 ballistic abnormalities?
Cold gun affect
Occasion to occasion affect
Order of fire
Ballistic hump
What are the ways to overcome the forces of a projectile
Nose shape
Base shape
Base bleed
What propellent was used in this graph?
Single
What propellent was used in this graph?
Double
Label this graph
What are the propellant form functions
Positive - most degressive
Positive near zero - neutral
Near zero
Negative - most progressive
What happens to the rate of burning of propellant if the pressure is increased
It increases
Name three types of flash suppression
Conical tube.
Slotted tube.
Bar type.
