Ballistics Flashcards
What is the definition of ballistics ?
The scientific study of the motion of projectiles.
What are the phases of ballistics?
Internal
Intermediate
External
Terminal
What are the objectives of INTERNAL ballistics?
Launch projectile safely
Launch projectiles with uniformity
Achieve the highest possible muzzle velocity
What are the phases of INTERNAL ballistics?
Charge ignition
Combustion prior to projectile motion
Combustion up to the all burnt point
Projectile motion after all burnt point to muzzle
What are some ballistic abnormalities?
The Warmer (Cold Gun) Effect
Occasion to occasion Effect
Order of Fire
Ballistic Hump
(BOOT)
What is the definition of INTERMEDIATE ballistics?
The study of the transition of internal to external ballistics that occurs in the vicinity of the muzzle.
What are the types of flash?
Pre-flash
Intermediate flash
Muzzle glow
Primary flash
Secondary flash
(PIMPS)
What are the flash reduction methods?
Muzzle devices (Flash suppressors)
Propellant type
Propellant additives
What are the additives added to propellant that reduce flash?
Potassium
Sodium
What are the two main sources of muzzle BLAST?
Blast shock
Flash blast
What is recoil?
The rearward motion of the gun in reaction to the forward motion imparted by the projectile and propellant gases
What is the disadvantage to countering recoil?
No sabot round can be fired as the break up of the propellant gasses interfere with the sabot discarding action.
What two elements make up bottle shock?
Barrel shock - Sides
Mach disc - Front
How do most flash suppressors reduce flash?
Break up the barrel shock
Mach Disc
What is trajectory?
The path taken by the centre of gravity of the projectile.
What are the properties of the projectile that effect ballistics?
Mass
Calibre
Nose shape
Spin rate
What properties of the atmosphere effect ballistics?
Air density
Temp
Pressure
What is meant by base drag acting on a projectile in flight?
The turbulent low pressure region immediately behind the base of the projectile pulling down on the projectile.
What is meant by the Ballistic Coefficient?
A scientific measure of a projectile’s carrying
ability
What are the two most common means of stabilisation ?
Fin
Spin
What are the drag forces ?
Skin Friction
Pressure Drag (Base Drag)
Forebody Drag
Excrescence
What are the two aerodynamic forces acting on a projectile depending on Yaw ?
Crosswind
Drag
What are methods of reducing drag?
Nose Shape - Reduce forebody drag.
Boat Tailing - Reduces pressure drag by minimising the area behind the projectile that low pressure can build up.
Base Bleeding - A pyrotechnic ignited on the base of a projectile to fill the low pressure area behind the base.
What is the definition of internal ballistics?
The scientific study of the process in the gun from the moment that the propellant is ignited until the projectile leaves the barrel
What is distance between the centre of gravity and the centre of pressure called?
Static margin
What propellent was used in this graph?
Single based
What propellent was used in this graph?
Double based
Label this graph.
Define Pioberts Law.
The surface of a burning propellant recedes layer by layer in a direction normal to the surface.
What are the types of muzzle suppression devices (flash suppressors) ?
Conical Tube
Slotted Tube
Bar Type
How does a bore evacuator work?
Prevents fumes entering the crew compartment by creating pressure differentials during and after fire. Gases are trapped in the evacuator and as the round exits the muzzle the gases follow.
What are the components of the precursor field.i
What are the 7 ways of regulating muzzle velocity?
Bore area
Charge weight
Chamber capacity
Propellant size
Ignition temp
Multiple variations
Shot Start
(BCCPIMS)
What is the effect of an increase in charge
weight?
Pressure increases, ABP moves back, muzzle velocity increases, regularity in fall of shot improves.
What are the forces acting on projectiles?
total drag, gravity, velocity vector, roll, yaw
What are the characteristics of propellants ?
Burning Rates
Force Constant
Form Function
Pressure Index
Co Volume
Ballistic Size
(BFFPCB)
What happens to the rate of burning of propellant if the pressure is increased?
Increased Burn Rate
Increased Temperature
All Burnt Point moves rearward
Increase in muzzle velocity
What are the three types of silencers ?
Absorption
Dissipation
Containment and controlled release
What is the Drag Coefficient?
Drag coefficient (C d )
quantifies the drag of an object through a fluid (Air or Water).
In cartridge cased ammunition the primer must what?
Provide rearward obturation to pressure loss
Withstand the initiation forces
