Summative Assessment 7

Question 1

What are the Objectives of Internal Ballistics?

Answer 1

• Launch the Projectile safely
• Consistent performance between shots
• Achieve the highest possible muzzle velocity

Question 2

Definition of Internal Ballistics

Answer 2

Scientific study of the operating process within the gun from the moment the propellant is ignited until the projectile leaves the barrel

Question 3

Define Pioberts Law

Answer 3

Surface of burning propellant recedes layer by layer in direction normal to the surface

Question 4

Characteristics of Propellants

Answer 4

• Burning Rate
• Pressure Index
• Force Constant
• Co-Volume
• Ballistic Size
• Form Function

Question 5

How to improve muzzle velocity for round for round regularity

Answer 5

If burning finishes while the shell is still well back in the bore

Question 6

What are the 6 areas of energy distribution?

Answer 6

• Projectile (translational & rotational)
• Residual heat of the gases
• Recoil of the gun
• Engraving the driving band/barrel friction
• unburnt charges and gases
• Heat lost to gun

Question 7

4 Phases of Internal Ballistics

Answer 7

• Charge Ignition
• Combustion prior to Projectile motion
• Combustion up to all burnt point
• Gas flow and projectile motion after all burnt point to muzzle

Question 8

Definition of Intermediate Ballistics

Answer 8

Study of the transition from internal to external ballistics that occurs in the vicinity of the muzzle

Question 9

What are the 2 phases of the muzzle gas flow field?

Answer 9

• The precursor blast field that proceeds the projectile exit of the muzzle
• The main blast field that follows as high pressure propellant gases are ejected into the air

Question 10

3 Main ways to minimise muzzle flash

Answer 10

• Muzzle Devices
• Choice of Propellant
• Propellant Additives

Question 11

How do Flash suppression devices reduce flash?

Answer 11

• Break up barrel shock and Mach disc

Question 12

What 2 elements make up bottle shock?

Answer 12

• Barrel shock

* Mach disc

Question 13

What are the 5 different types of flash?

Answer 13

• Pre-flash
• Primary Flash
• Muzzle glow
• Intermediate flash
• Secondary flash

Question 14

What does a bore evacuator do?

Answer 14

• Prevents propellant fumes from entering crew compartments
• Works by creating pressure differentials during and after firing
• High pressure propellant gases are stored in the evacuator as the round passes through the barrel
• As round exits muzzle the high pressure gases flow out the muzzle
• This May increase the secondary flash

Question 15

What forces act upon a projectile?

Answer 15

• Drag
• Pressure
• Yaw
• Velocity
• Roll

Question 16

What are ways to overcome forces of a projectile?

Answer 16

• Nose shape
• Base shape
• Base bleed

Question 17

Definition of Terminal Effects

Answer 17

The study of projectile behaviour at the target

Question 18

What are the fundamental elements of Terminal Effects?

Answer 18

• Kinetic Energy
• Projectiles Physical properties
• Target type

Question 19

What factors can affect projectile penetration?

Answer 19

• Projo Velocity

* Density

Question 20

How does ceramic armour prevent penetration?

Answer 20

By reducing the projectile nose mass whilst projo core decelerates

Question 21

What are the 4 types of Drag?

Answer 21

• Skin Friction
• Forebody Drag
• Pressure Drag
• Excrescence