SA06 - Fuzes Flashcards
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Definition of fuze
A fuze is a device designed to function an item of ammunition under pre-determined circumstances
OR
A device designed to initiate an explosvie munition at the corrcet time or place
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
What are other requirements of a fuze?
- Optional delay setting
- Easy time adjustment / setting
- Minimum preparation for use
- Multi role to minimise refuzing
- Standard weight and cavity size
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
What is the standard cavity size for Mortar and Artillery fuzes
- Mortar - 1.5 inch
- Artillery - 2 inch
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Full form of different fuzes by position and function
Position - PD, BD, PIBD
Function - MT, CT, PDSQ, MTSQ, DEL, VT, CVT, TSQ, MO
Requirements and Classification of fuzes
common method of operation of fuze (4 stages)
- Unlocking a component by set-back forces.
- Easing it on its seating during creep forward.
- Swinging it to an armed position by the application of centrifugal force.
- Initiation of the explosive train by set forward on impact.
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Classification of fuzes
- Position
- Filling
- Function
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Types of fuze by function
- Impact
- Time
- Prox
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Types of fuze by position
- Nose (PD)
- Base (BD)
- Combination (PIBD)
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Types of fuze by filling
- Disruptive
- Igniferous
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Types of Time fuze
- Combustion Time (CT)
- Mechanical Time (MT)
- Combination
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Types of Impact fuze
- PDSQ
- Graze
- Delay
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Types of prox fuzes
- Variable time (VT)
- Controlled Variable Time (CVT)
Requirements and Classification of fuzes - REMEMBER THIS QUESTION
Forces acting on a fuze
- Setback
- Centrifugal
- Spin decay
- Creep forward
- Set forward
- Air or gas pressure
- Stored energy
Mechanical devices and fuze components - REMEMBER THIS QUESTION
Principle requirements of the fuzes
- Safety
- during storage and handling
- from premature functioning
- Reliability to high order when required
Mechanical devices and fuze components
Types of safety mechanism in a fuze
- Holding Devices
- Locking Devices
- Safety Devices
Mechanical devices and fuze components
Categories of fuze
- Mechanical and Electro/Mechanical - Out of line.
- Electronic/Mechanical - Out of line.
- Electronic - In line.
Mechanical devices and fuze components
Function of mechanical devices embodied in
the fuze
To ensure that the fuze:
* Functions at the desired moment
* Remains safe in handling, before and during loading
* Remains bore and muzzle safety immediately after firing
* Arms after leaving the muzzle
Mechanical devices and fuze components - REMEMBER THIS QUESTION
Definition of holding devices
A holding device locks other components in a safe position until arming is required; to unlock them when arming is required; and possibly to relock them in the armed position.
Mechanical devices and fuze components
Types of holding devices
- Shear wire
- Striker spring and spring disc
- Detent/ Setback pin
- Centrifugal balls
- Setback
- Centrifugal
- Creep forward - Stirrup spring and Ferrule
- Stirrup spring
- Ferrule
- Horse head segments
- Bore riding pin
Mechanical devices and fuze components
Definition of firing devices
A firing device is the component which provides the stimuli to initiate the explosive train.
Mechanical devices and fuze components
Ways to activate a firing device
- Electrical
- Mechanical
Mechanical devices and fuze components
Types of electric firing devices
- Conducting Cap (CC).
- Bridge Wire (BW).
- Exploding Bridge Wire type (EBW).
Mechanical devices and fuze components
What are the other fuze components?
- Pellets.
- Detonators.
- Magazine or booster.
- Channel.
- Protective Cover/Cap:
Striker Cover.
Safety Cap. - Delay Systems.
Mechanical devices and fuze components - REMEMBER THIS QUESTION
Advantages of electronic fuzes
- Lowers costs due to multi role function.
- Versatility in arming.
- Mechanical preparation or initiation.
Mechanical devices and fuze components - REMEMBER THIS QUESTION
There are two type of Masking Devices. What are they?
- Non Delay Arming or Masking Shutters and Slides.
- Delayed Arming Shutter.
Intro to Time Fuzes - REMEMBER THIS QUESTION
What is time fuze?
Time Fuzes are designed to function after a predetermined time whilst in flight.
Intro to Time Fuzes
How are time fuzes are set for time before loading?
- Rotation
- Use of a moving portion of fuze with fuze key
- Fuze setter
- Fuze setting machine
Intro to Time Fuzes - REMEMBER THIS QUESTION
Types of time fuzes
- Combustion (T) – Powder Train Time Fuze (PTTF)
- Mechanical (MT)
- Electronic (ET)
Intro to Time Fuzes - REMEMBER THIS QUESTION
3 mechanisms of MT fuze
- THIEL - British MT Fuzes
- JUNGHANS - American MT Fuzes
- DIXI - Swiss Fuze
Intro to Prox Fuzes - REMEMBER THIS QUESTION
Definition of prox fuze
Proximity fuzes are automatic time fuzes, with or without PD element, that are designed to function a projectile at the optimum lethal distance from the target, provided that in the case of aircraft targets, the trajectory passes sufficiently close.
Intro to Prox Fuzes
Design consideration for prox fuzes
- Rugged.
- Able to function in all conditions.
- Light weight.
- Economical.
- Able to fit existing projectiles.
- Sensitive and rapid in operation.
- Not easily jammed.
- Not subject to false operation.
- Safe to handle.
- Have good storage characteristics.
Intro to Prox fuzes
Sections of Prox fuze
- The nose
- The steel base
- The sleeve
Intro to Prox fuzes - REMEMBER THIS QUESTION
What is 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.
Intro to Prox fuzes - REMEMBER THIS QUESTION
How does prox fuze function?
- On firing, setback breaks the ampoule or electrolyte which floods the energiser.
- Clock starts (CVT only) and the shutter starts to rotate.
- An electric igniter is short circuited until 3 - 5 seconds after firing.
- Transmitter radiates radio waves.
- Nearing the target… Doppler effect activates
- FUZE DETONATES.
Intro to Prox fuzes
What must the Prox fuzes be protected from?
- Dampness.
- Sunlight .
- Heat.
- Drop / Strike.
Intro to Prox fuzes
Why are prox fuzes commonly stored nose down?
The battery ampoule activates on setback (rearward), so impact nose-down is less likely to activate the battery.
Intro to Prox fuzes
What are elctronic fuzes?
Electronic fuzes are functioned by a current passing through electric leads from some sort of battery
Intro to Prox fuzes
Power Sources in Electronic fuzes
- Battery
- Turbine generated
- Precharged
- Electostatic
Intro to Prox fuzes
What are the option in MO fuzes?
- Proximity
- Superquick
- Delay
- Near surface burst
Intro to Prox fuzes
What results can be expected from a Proximity Fuze when dropped from 1m or more?
Care should be taken not to strike or drop fuzes or fuzed rounds because a drop in excess of 1m may result in a UXO when fired.
Intro to Impact fuzes - REMEMBER THIS QUESTION
Impact fuzes actions
- Superquick (SQ).
- Non Delay.
- Graze.
- Delay.
Intro to Impact fuzes - REMEMBER THIS QUESTION
Explain graze action elements
- The interior mechanism of graze action fuzes is so arranged that when the projectile is checked in flight or receives an appreciable deceleration.
- A moveable part, usually called the graze, inertia pellet or plunger moves forward to carry the detonator on to the needle (or vice versa).
- A creep spring keeps the two apart until this deceleration is experienced.
- As the movement of the plunger or weighted needle gives rise to an ‘air gap’ the fuze detonator is of the flash type.
- Graze fuzes have a small inherent delay.
Intro to Impact fuzes - REMEMBER THIS QUESTION
Parts of 105mm FD HE Fuze PD L32A3
Slide 16 of Impact fuzes powerpoint
Design characteristics of fuzes
Remember HN ARSENALS
- Have a good storage charcteristics
- Not easily jammed
- Able to fit existing projectiles
- Rugged
- Sensitive and rapid in operation
- Economical
- Not subject to false operation
- Able to function in all conditions
- Light weight
- Safe to handle
