SA5 Directed Study Flashcards
What is ballistics?
The scientific study of the motion of projectiles
What is internal ballisics
The scientific study of the operating processes within the gun from the moment that the propellant is ignited until the projectile leaves the gun.
What are the objectives of internal ballistics
Launce the projectile safely
Consistent performance between shots
Achieve highest possible muzzle velocity
What are the four parts of a gun
Breech
Chamber
Barrel
Muzzle
What are the phases of internal ballistics
Charge ignition
Combustion prior to projectile motion
Combustion up to all burnt point
Gas flow and projectile motion after all burnt point to muzzle
What is pioberts law?
Surface of a burning propellant reduces layer by layer in a direction normal to the surface
What is silver point
In multi tubular propellant, the holes expand to meet each other creating silvers of unburnt propellant. This then becomes a degressive burn
What is intermediate ballistics?
Is the study of the transition from internal to external ballistics
What is bottle shock?
Bottle shock which consists of barrel shock being the sides and mach disc being the front.
What are the two types of shock
Blast shock and bottle shock
What are six areas that energy is distributed when the gun is fired?
Projectile
Heat in the gas
Gun recoil
Driving band engraved
unburnt charge/gas
Heat in the gun
Types of drag forces
Skin friction
Pressure drag (base drag)
forebody drag
excrescence drag
What are the three types of silencers?
Blast absorption
Blast dissipation
Blast containment and controlled release
What are flash reduction methods?
Muzzle devices
Type of propellant
Propellant additives
What are the three types of flash supressors
Conical tube
Slotted tube
Bar type
What are the five types of muzzle flash?
Pre-flash
Primary flash
Muzzle glow
intermediate flash
secondary flash
What is a bore evacuator?
Prevents propellant fumes from entering the crew compartments
How does a bore evacuator work?
High pressure propellant gases are stored in the evacuator as the projectile passes through
As the round exits the muzzle the pressure gasses flow out the muzzle
May increase secondary flash
Methods of reducing the effect of base drag
Boat tailing, base bleed
