Fuzes Flashcards
What is the definition of a fuze?
A fuze is a device designed to function an item of ammunition under pre determined circumstances
What do the abbreviation by position of fuze PD, BD and PIBD mean?
PD - Point Detonating
BD - Base Detonating
PIBD - Point Initiating Base Detonating
What do the abbreviation by function T, CT, MT, VT, CVT, SQ, DEL, MTSQ, TSQ, PDSQ, MO, ET mean?
T - Time
CT - Combustion Time (May also be PTTF)
MT - Mechanical Time
VT - Variable Time
CVT - Controlled Variable Time
SQ - Super Quick
DEL - Delay
MTSQ - Mechanical Time Super Quick
TSQ - Time Super Quick
PDSQ - Point Detonating Super Quick
MO - Multi Option
ET - Electronic Time
What are the 3 general and 6 other requirements for fuzes?
General
-Safety for storage and transport
-Safety against premature firing
-Reliability to high order when required
Other
-option for delay setting
-easy time adjustment/setting
-minimum prep time
-multi role to minimise fuzing
-standard weight
-must fit standard cavity size
(SSR MEMOMS)
What 7 forces act on the fuze that can be used for arming and functioning?
Set Back
Set Forward
Creep Forward
Spin Decay
Centrifugal Force
Air or Gas Pressure
Stored Energy
What are the required amount of independent forces that must act on the fuze during the arming sequence?
Two
What are the principle requirements of mechanical devices and fuze components?
-Functions at the desired moment
-Remains safe in handling
-Bore and muzzle safety immediately after firing
- Arms after leaving the muzzle
What are the 3 safety and arming mechanisms?
Holding device
Locking device
Safety device
What are 6 other fuze components?
Protective Cap
Pellets
Delay Systems
Detonators
Magazine or booster
Channel
(PPDDMC)
What are the 3 advantages to using electronic fuzes?
Lowers costs due to multi role function
Versatility in arming
Mechanical preparation or initiation
What are the three categories of time fuze ?
Mechanical
Combustion
Electronic
What is the definition of a prox fuze?
Proximity fuzes are automatic time fuzes that are designed to function a projectile at the optimum lethal distance from the target.
Proximity fuzes can be divided into what two groups?
Variable time (VT)
Controlled variable time (CVT)
What are the 4 impact fuze actions?
Super quick
Graze
Non delay
Delay
Fuzes classified by function have what three types?
Time
Impact
Proximity
Fuzes are classified according to what three categories?
Filling
Position
Function
Describe the doppler effect -
Radio waves are emitted by the fuze, the waves reflected are picked up by the reciever. As the fuze gets closer to the set target distance the impulses increase to a defined peak value and the fuze functions.
What is stored energy?
(Mechanical) usually a spring used to operate clockwork devices or shutters.
What is air or gas pressure?
Pressure is sometimes used to drive a turbine to generate power for electrically operated fuzes
What are the 4 options on a multi option fuze?
Proximity
Super quick
Delay
Near surface burst
What are the three distinct types of MT fuze mechanisms
THIEL - British MT Fuzes
- A series of wheels and pinions controls the escape of from a main spring which is wound up during manufacture
JUNGHANS - American MT Fuzes
- This mechanism is actuated by spring assisted by centrifugal weights
DIXI - Swiss Fuze
- This mechanism is driven by centrifugal force acting on driving balls
What are the 4 power sources for proximity fuzes?
Battery
Turbine generated
Precharged
Electrostatic
What are the 10 design considerations for prox fuzes?
Have good storage characteristics.
Not easily jammed.
Able to function in all conditions.
Rugged.
Safe to handle.
Economical.
Not subject to false operation.
Able to fit existing projectiles.
Light weight.
Sensitive and rapid in operation.
(HN ARSENALS)
How does graze fuzing work?
A movable part (graze inertia pellet or plunger) carries the detonator onto the needle once the projectile is checked in flight or decelerates.
What are the 3 basic sections of a prox fuze
Nose
Steel Base
Sleeve
What is a holding device?
Locks other components in a safe position until arming is required, unlock them and can possibly re-lock.
What are the 3 safety devices used in unspun ordnance (mortars/rockets) when centrifugal force cannot be used?
Safety Pins
Cotter Pins
Pull Pins
What is the common method of operation for fuzes?
Unlocking a component by set back, easing it on its seating during creep forward, Swinging it to an armed position by centrifugal force.
Initiation of the explosive train by set forward on impact.
Definition of a Time Fuze
A fuze designed to function after a predetermined time whilst in flight.
How are time fuzes set before loading? 4 ways
Rotation
Moving a portion of fuze with fuze key
Fuze setter
Fuze setting machine
What are the standard cavity types for fuzes?
Mortar - 1.5 inch
Artillery - 2 inch
2 types of masking devices
Delay or non delay masking Shutter and sliders
Delay Arming Shutter
What is an inertia pellet?
A heavy weight that carries the detonator on rapid deceleration into the firing pin.
Explain when a fuze is armed.
A fuze is armed when it has gone through all of its firing forces and the explosive train is in line.
In design safety, the system shall be designed so that what?
Cannot be assembled in an unsafe condition
Safety arrangements can be checked during and after assembly
In storage what 4 things should Prox fuses be protected from and in what orientation should they be stored?
Dampness
Sunlight
Heat
Drop / Strike
commonly stored nose down IOT protect the battery ampoule.
