Test 10 - Mortars Flashcards
What is the primary ignition cart used on 60mm mortars?
M702 Ignition Cart
What is the candle power for 60mm Illum M721?
Max 400 000 for 40secs
Min 250 000 for 32secs
What is the luminosity and burn time for 60mm IR Illum M767?
500 at near IR wavelength of the electromagnetic part of the spectrum
40 sec
*** How does the fuse PD M775 work?
- Safety pin is removed.
- upon acceleration from firing, the setback pin moves rearward against a spring, releasing a slider, which holds the striker in its rearward position.
- Once the striker is released, it travels upward allowing the ball bearings to be forced into central alignment between the striker and the primer.
- On impact, the striker is driven into the ball bearings, which initiate the primer, igniting the pyrotechnic smoke cartridge.
- The pyro smk charge produces a flash, audible sound and smoke to simulate HE
How does the Fuze PD (MO) M783 work?
On firing, setback sensor in S and A recognises launch acceleration, releasing the 1st rotor lock (zigzag).
As the mortar travels through its flight, air is forced into the venturi, turning the turbine and generating power.
At the same time the turbine drives the gear train into the S and A to remove 2nd rotor lock (jackscrew).
The gear train provides 100m arming distance.
Once rotor unlocks it rotates 180˚ and latches, this Aligns primary and secondary explosive elements, Connects the elec det.
Once S and A is fully armed, there is an elec delay to the elec arming until post round apogee by monitoring turbine frequency.
What is the arming distance for the M783 PD (MO) fuse?
100m
What are the four settings for the Fuze M734A1?
Prox - 14ft
NSB - 7ft
Impact
Delay - 50-150ms
Label the 60mm IR Illum mortar.
Ignition cart M702 Fin M27 4 Propelling charge M204/M235 Base plate Obturating Ring Orange Band Illuminant First fire composition Identification Strip Time fuse M776
What is the minimum safety arming distance for MTSQ M772?
40m
How does the 81mm Illum work?
Obturator ring expands under gas pressure from burning propellant causing forward obturation. The gases propel the mortar bomb. The setback force during firing unlocks the fuses setback safety device, commencing the arming sequence. When it reaches pre selected flight time, the fuse functions and initiates the booster. The internal pressure build up causes separation of the front and tail cone sections by fracturing the shear pins. The illuminating assembly is ejected rearwards from the front section of the mortar body. Simultaneously, the fuse booster initiates the ignition system of the illuminant canister. Deployment of the parachute controls the rate of descent.
How many wedges and what weight are in the 81mm Smk RP? (2)
- 28 wedges
- 43g
What is in the 81mm Smk RP? (3)
M752A1 Ignition Cart
M218 Propelling Charge
M819 Loading Assembly
What is the GAM? what is it used for, life expectancy and must do with it? (4)
- Gas Absorbent Module
- The primary function of the GAM is to absorb the decomposition by-products of the RP (phosphine gas).
- life expectancy between 7 to 10 years.
- Must be removed prior to firing
What are the Fuze settings for Smoke/Illum and why?
Mech time - 4-56 secs. To function in the air for optimum spread or to illuminate a target area.
SQ - backup incase the MT doesn’t work.
What powers the MO M734?
The turbine alternator assembly is responsible for supplying both electrical and mechanical energy to the fuse.
When would you not use an inert replica round?
When it is observed to be degrading or turning yellow in colour