Formative 5 Revision

Question 1

define internal ballistics

Answer 1

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

Question 2

what are the goals of internal ballistics?

Answer 2

launch the projectile safely
launch the projectile with uniformity
achieve constant muzzle velocity

Question 3

what is pioberts law?

Answer 3

the surface of a burning propellant receeds layer by layer in a direction normal to the surface

Question 4

what factors effect the burning rate of propellant?

Answer 4

size
pressure
temperature
shape

Question 5

what is the distribution of energy?

Answer 5

• Projectile 32%
• Residual heat of the gases 42%
• Recoil of the gun 0.2%
• Engraving of the driving band 2.8%
• Unburnt charges and hases 3%
• Heat lost to the gun 20%

Question 6

what is the effect of an increase in charge weight?

Answer 6

Pressure increases
ABP moves back
Muzzle velocity increases
Regularity in fall of ahot improves

Question 7

what is the definition of intermediate ballistics?

Answer 7

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

Question 8

what are the two phases of the muzzle gas flow

Answer 8

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

Question 9

what is bottle shock and its two parts?

Answer 9

the projectile pushes air along the bore, so that when it exits the barrel it forms a shockwave.

• barrel shock
• mach disc

Question 10

what are the types of muzzle flash?

Answer 10

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

(P.P.M.I.S)

Question 11

how do you minimise flash?

Answer 11

• Muzzle devices
• Type of propellant
• Propellant additives

Question 12

name the 4 types of drag

Answer 12

• skin friction
• base drag
• forebody drag
• Excrescence drag

Question 13

what are some methods to reduce drag?

Answer 13

• Base bleed

- Boatailing

Question 14

what are the types of influence fuzes?

Answer 14

• Magnetic
• Acoustic
• Seismic
• Hydrostatic

Question 15

what is an influence fuze?

Answer 15

a weapon subsystem that activates is warhead mechanism in the vincinity of a target and also keeps the warhead in a safe condition during all prior phases

Question 16

what is a masking device? and its types

Answer 16

it obstructs the explosive train until arming is required, ensuring that if accidental prematire function of on part does occur it does not effect the whole train

Question 17

what are the fuze principle requirements?

Answer 17

safety and reliability

Question 18

a fuze is armed when?

Answer 18

all the safety components have been removed

Question 19

what is the operation of a bore rodding pin?

Answer 19

a steel pin is not ejected until the projectile leaves the bore of the weapon - proving safety by interrupting tje arming mechanism

Question 20

what are the forces acting on a fuze when firing?

Answer 20

• Set back
• Set forward
• Side slap
• Centrifugal
• Creep forward

Question 21

what are the forces acting on a fuze in flight?

Answer 21

• Crosswind

- drift

Question 22

what are the impact fuze actions?

Answer 22

• super quick
• non delay
• delay
• graze

Question 23

what are three impact fuze catergories?

Answer 23

• point detonating
• base detonating
• point initiating base detonating

Question 24

define a booster

Answer 24

a booster amplifies the detonation wave from a fuze to a larger charge such as a HE filling

Question 25

what are the requirements of a fuze?

Answer 25

safety and reliability

Question 26

what is the main design function of time fuzes?

Answer 26

designed to function a projectilr whilst in flight

Question 27

what are the types of mechanisms in time fuzes?

Answer 27

• Thiel
• Tavaro
• Junghans
• Dixi

Question 28

what is the doppler effect?

Answer 28

radio waves are reflected and picked up by the receiver within the fuze. reflected waves interfere with the radiated waves to give a beat known as the doppler effect. as the fuze gets closer to the target, the impulses increase to a defined peak value and the fuze functions.