SA06 - Fuzes Flashcards by Ammo Tech

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

A device designed to initiate an explosvie munition at the corrcet time or place

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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

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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

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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

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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.

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Requirements and Classification of fuzes - REMEMBER THIS QUESTION

Classification of fuzes

Position
Filling
Function

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Requirements and Classification of fuzes - REMEMBER THIS QUESTION

Types of fuze by function

Impact
Time
Prox

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Requirements and Classification of fuzes - REMEMBER THIS QUESTION

Types of fuze by position

Nose (PD)
Base (BD)
Combination (PIBD)

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Requirements and Classification of fuzes - REMEMBER THIS QUESTION

Types of fuze by filling

Disruptive
Igniferous

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Requirements and Classification of fuzes - REMEMBER THIS QUESTION

Types of Time fuze

Combustion Time (CT)
Mechanical Time (MT)
Combination

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Requirements and Classification of fuzes - REMEMBER THIS QUESTION

Types of Impact fuze

PDSQ
Graze
Delay

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Requirements and Classification of fuzes - REMEMBER THIS QUESTION

Types of prox fuzes

Variable time (VT)
Controlled Variable Time (CVT)

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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

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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

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Mechanical devices and fuze components

Types of safety mechanism in a fuze

Holding Devices
Locking Devices
Safety Devices

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Mechanical devices and fuze components

Categories of fuze

Mechanical and Electro/Mechanical - Out of line.
Electronic/Mechanical - Out of line.
Electronic - In line.

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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

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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