Recoilless Flashcards
551 Rocket Motor Assembly (RMA) components
Body
Propelling charge
Aft closure
Delay charge
Intermediate charge
Ignition charge
551 How is the RMA secured to the projectile body in the 551
Secured to the projectile body by an internal
thread
551 Tail fin assembly 551
Six cold extruded aluminium fins
A plunger (incorporating two throttling orifices)
551 What do the fins achieve on the 551
Reducing the spin rate to approx 450 rpm
551 Arming distance
The arming spring then moves the rotor through 270 degrees to the armed position (5 to 15 metres into the flight)
Muzzle velocity of FFV551
255 m/s
Angle of Impact FFV551
10 deg minimum
Range HEAT 551
150m-700m
Operating limitations General FFV551
Temperature : -40ºC to +71ºC
Firing from within enclosed positions prohibited
Double hearing protection pers within 25m
Wearing of hearing protection within 100m of firing
There should be no range obstructions to 30m from the firing point
Targets to be @ > than 150m
*Ricochet Distance FFV551
350m normal target Hard Target 700m
Operating Limitations Cook Off FFV551
A platform temperature of 115ºC should not be exceeded
A maximum of ten rounds may be fired in close sequence
A maximum of twenty five rounds can be fired at a rate of fire of six rounds per minute
Rate of fire for prolonged firings is to be considerably less than five rounds per minute
*Operating Limits Blast Overpressure FFV551
Blast Overpressure: Number of firings per firer per day (peace time):
Standing seven
Kneeling/Sitting one
Prone zero in peacetime
Proof Requirements FFV 551
Proof Requirements
Functional requirements
Penetration of Armour 400mm (approx) and produce behind armour effects
Must function on both direct impact and graze impact on a target
When fired at the centre of a vertical target, at 300+5m the max distance between the MPI and point of aim must not exceed 0.4m
551 What is the RKT MT propellant type & QTY?
AKB 250m Double Based Strip 270g
Critical Performance Parameters (CPP) FFV551
Positions of Impact Points on the target Vertical and horizontal co ordinates of impact points, measured from the lower left hand corner of the target, are to be recorded
Positive values on the horizontal axis are to the right of the lower left hand corner (recorded in metres)
Muzzle Velocity is to be recorded for all tests
Blast Over Pressure is to be recorded for all tests
Rocket Motor Ignition Distance Rounds are to be observed to determine whether a Ignition Distance of at least 13m is achieved.
Recoil Energy Recoil Energy (Joules) is to be recorded for all tests
Weapon system for 545/545C
84mm M1/2 Medium Direct Fire Weapon System Carl Gustaf
84mm M3 Carl Gustaf – replacement variant
545/545C construction
Flare container
Filled: 0.57kg of Magnesium/Sodium Nitrate
Illuminating Composition
Produces 650,000 candlepower
Average burn time: 30 + 5 seconds
Parachute
Connected to Illumination canister by a swivel
Nylon canopy and shroud lines
Asbestos-fabric Flare Shield
Slows candle descent rate to 5m/s
Three short and one long half-casing surround
parachute assembly
545 Combustion time fuze time setting
The ring has graduations from 200 metres to 2300 metres in 50 metre increments and an ‘S’ graduation to indicate safe
Additionally, the ring has three preset catches at the 600, 1100 and 1700 metre graduations to allow setting of the fuze to these distances in total darkness
The fuze is supplied in the ‘S’ position and the ring may only be turned in an anti-clockwise direction where the distance decreases starting at 2300 metres
545 luminosity
650000 candlepower for
30 seconds
545 Muzzle velocity
260 m/s
545 Arming distance
20-70m
545 HOB
200m (approx) - achieved with eleveations of 20° @ 500-1800 and 25° for 300-400 and 1900-2300m using a luminous flare pendulum sight
Cart 84mm 545 has the following functional
requirements:
Time to Burst. At a charge temperature of +21ºC, the time to burst, and corresponding distances are:
600m (short range) 2.6 sec 0.25 sec
1100m (medium range) 5.5 sec 0.30 sec
1700m (long range) 9.4 sec 0.35 sec
545 Critical Performance Parameters (CPP)
a. Time to Burst. Flight times (seconds) before burst
b. Muzzle Velocity. Muzzle Velocity, vm(ms 1),
c. Blast Overpressure (BOP). Blast overpressure (kPa)
d. Recoil Energy. Recoil Energy (joules) is to be recorded for all tests
e. Candle Burn Time.
f. Luminosity.
545 Test Reqs.
Muzzle Velocity and Functioning. Rounds are to be conditioned at 21º C + 2º C for a minimum of 12 consecutive hours
Point of Aim. Quadrant elevation is to be 20º
FFV545C difference from 545
Includes Electronic Fuze F555, has I for impact mode (200 G’s)