Test 6 - Fuzes Flashcards
Define Fuze:
A fuze is a device designed to function an item of ammunition under pre-determined circumstances
3 Classifications of Fuzes:
- Filling
- Position
- Function
Define the following: PD BD PIBD T CT MT VT CVT SQ DLY MTSQ TSQ PDSQ MO ET
Point Detonating Base Detonating Point Initiating Base Detonating Time Combustion Time Mech Time Variable Time Controlled Variable Time Super Quick Delay Mech Time Super Quick Time Super Quick Point Detonating Super Quick Multi Option Electronic Time
2 General Requirements of Fuzes:
- Safety
- For storage and Transport
- Against Premature functioning
- Reliability
- To high order when required
One of the other requirements of a fuse is that it fits the fuse cavity, name five more?
E - Easy time adjustments/setting O - Optional delay setting M - Must fit standard cavity sizes M - Minimum preparation for use M - Multi role to minimise refusing S - Standard weight
One mechanical device is a Shutter, name three more.
Delay arming shutter Masking (delay or non delay) Horse head segments Bore riding pin Centrifugal balls
Explain when a fuse is armed/What is the process of arming?
A fuse is armed when it has gone through all of it’s firing forces and the explosive train is inline.
Explain the following:
- Setback
- Stored energy
- Creep forward
- Centrifugal force
- Set forward
- Spin decay
- Air/gas pressure
- Setback - Rearward Momemtum caused by rapid acceleration forces
- Stored energy - energy ready to be released (spring under tension)
- Creep forward - After setback and the momentum starts to decelerate, moving parts return to a forward position
- Centrifugal force - momentum moves outwards due to a rapid spinning motion
- Set forward - Forward Momentum caused by violent deceleration on impact
- Spin decay - decrease in angular velocity
- Air/gas pressure - used to drive a turbine to generate power in electrically operated fuses
What are the four Impact fuse actions?
- Super quick
- Non delay
- Graze
- Delay
What are the categories of impact fuses?
- PD
- BD
- PIBD
How does graze sensitive work?
Functioned when checked in flight or receives appreciable deceleration, the inertia pellet moves forward to carry the detonator on to the striker or vice versa.
A creep spring keeps the two apart. The detonator is a flash type and the fuse has a small delay.
What are boosters made of and what are they for?
CE pellet
Carries the explosive wave from the detonator and transfers it to the main fill
What are the three types of time fuses?
- Combustion time
- Mechanical time
- Electronic time
What are the three types of mechanical time fuses?
- THIEL - British MT Fuzes
- JUNGHANS - American MT Fuzes
- DIXI - Swiss Fuze
Differences between VT and CVT?
- Variable time - were unreliable due to premature functioning as they did not contain arming delay mechanisms
- Controlled variable time - incorporate a clockwork mechanism which prevents the VT element from functioning except during that portion of the trajectory which is close to the target
Two of the design considerations for a proximity fuse are:
- Sensitive and rapid in operation
- Not subject to false operation
Name three more.
- Rugged
- Able to function in all conditions
- Lightweight
- Economical
- Able to fit existing projectiles
- Not easily jammed
- Safe to handle
- Have good storage characteristics
Describe the Doppler effect.
- Radio waves are emitted by the fuze, some of the waves are reflected and picked up by the receiver
- The time taken to return affects the reflected waves, which interfere with the radiated waves to give a beat known as the Doppler effect
- As the Fuze gets closer to the set target distance the impulses increase to a defined peak value and the fuze functions
8 Other Components of Fuzes?
P - Pellets P - Protective Cover/Cap S - Striker Cover S - Safety Cap D - Detonators D - Delay Systems B - Booster or Magazine C - Channel
3 Advantages of Electronic Fuzes:
- Lowers costs due to multi role function
- Versatility in arming
- Mechanical Preparation or initiation
2 Categories of Masking Devices?
- Delay
- Non-Delay
What are time fuzes designed to do?
Function after a predetermined time whilst in flight.
How are time fuzes set for time prior to loading? (4)
R - Rotation
U - Use of a moving portion of fuze with fuze key
F - Fuze setter
F - Fuze setting machine
3 Types of Time Fuzes?
- Combustion (T)- Powder Train Time Fuze (PTTF)
- Mechanical (MT)
- Electronic (ET)
7 Forces Available to act upon fuzes + quick explanation of each?
- Set-back
- Creep Forward
- Centrifugal Force
- Spin Decay
- Set Forward
- Air or Gas Pressure
- Stored Energy
What is a bore riding pin?
A pin that rides inside the bore and when the item leaves the bore the pin ejects by spring tension and the explosive train is aligned
What is an inertia pellet?
A heavy weight that carries the detonator on rapid deceleration into the firing pin
3 Sections of the Prox Fuze?
- Nose
- Steel Base
- Sleeve
2 Groups of Proximity Fuzes
VT
CVT
Define Proximity Fuzes?
An automatic time fuze with or without PD element designed to function at the optimum lethal distance from target.
What are the safety features for mechanical fuzes?
- Cannot be assembled in unsafe condition
- Safety arrangements can be checked during and after assembly
Types of Shutters? (2)
- Sliding Shutter
- Rotating Shutter
What are the 4 power sources for Elec Fuzes?
- Battery
- Turbine Generated
- Pre-charged
- Electro static
Settings for MO Fuzes? (4)
- Delay
- Prox
- Near Surface Burst
- SuperQuick
