Test 8 - Theory of Design Flashcards
4 Principles of RCL?
- If two equal weights can be fired in the opposite directions at equal velocity the weapon will be recoilless
- possible to use a counter shot of half the weight if it can be fired at twice the velocity
- counter shot replaced by stream of very light gas
- obturated breech is replaced by the venturi
3 Advantages of RCL Systems?
- No Recoil
- Low Weight
- Man Portable (84mm)
3 Disadvantages of RCL Systems?
- Low Velocity
- Flash / Dust Signature
- Large propelling charge
What replaces the breech obturator in RCL systems?
- Venturi
2 + 1 Sections of FFRs?
- Motor (including combustion chamber, fins and nozzle)
- Warhead (including fuze)
- Launcher
6 Components of an FFR rocket motor?
C - Casing P - Propellant C - Combustion Chamber F - Fins (if not spin stabilised) I - Igniter N - Nozzle (s)
6 Types of Warheads for FFRs?
- Nuclear
- HE
- Chem (incl smoke)
- Sub Munitions
- Terminally Guided Munitions
- Prac
4 Characteristics of FFRs?
C - Casing strong to withstand the pressure/temp of combustion
O - Only use boost motors
M - Made of various steels
D - De Laval nozzles normally used (convergent - Divergent)
What 3 factors affect the accuracy of FFRs?
- Surface Cross Winds
- Burning Rate of Propellant
- Launcher induced Errors
What is the main type of propellant used in FFRs?
Solid Propellant
4 Ways to overcome thrust misalignment in FFRs?
- Manufacturing to closer tolerances
- Impart a slower rate of spin
- Reduced rocket motor burning time
- Addition of fins
What is the type of Nozzle used in FFRs and how does it work?
- De Laval Nozzle
- High pressure sub sonic gas is transferred into low pressure super sonic gas.
Define Grenade?
- Small explosive store designed for projection by hand or from a personal weapon.
3 Design Categories for Grenades?
- Hand Thrown
- Projected - Rifle launched/gun fired
- Discharger - weapon/vehicle launched
8 Types of Payload/filling for Grenades?
- HE Anti Pers
- HEAT
- Smk
- Chem
- Flash
- Incendiary
- Prac
- Illum
5 Components of a Grenade?
- Body
- Filling
- Frag
- Fuze Cavity
- Fuze
6 Components of a Grenade Fuze?
S - Safety Pin S - Striker / Percussion Cap S - Spring F - Fly off lever D - Detonator D - Delay Pellet
2 Types of HE Grenades?
- Offensive (Blast)
- Defensive (Blast and Frag)
2 Types of Smk Grenades?
- Signalling
- Screening
Define SAA?
Ammunition for weapons such as pistols, rifles and machine guns below 20mm in calibre.
** 4 Components / Main Parts of SAA
- CC
- Ignition System
- Propellant Charge
- Projectile
** 4 Influences/ contour factors for SAA CC?
- Role of the ammo
- Type of weapon
- Projectile design
- Ignition system
A SAA CC must HAVE THE FOLLOWING REQUIREMENTS? (4)
R - Resist corrosion
C - Contract to allow extraction
B - Be sufficiently expandable to provide obturation
S - Strong enough to withstand transportation and handling
How are large propellant charges accommodated in SAA CC’s?
- Made larger than the diameter of the proj
- Necked down at the forward end
What ideal combination of attributes does Brass provide? (4)
- Strength
- Hardness
- Elasticity
- Resistance
How is Brass CC manufactured?
- Drawn from a disc, stamped from a sheet
- Deep drawing done in several stages
Why is a soft mouth necessary for SAA CC? (3)
- Expand as soon as pressure rises in chamber?
- Establishes an early seal
- Prevents gas leakage
Why is a hard base necessary for SAA CC? (2)
- Withstand internal pressure and rearward thrust from propellant gases
- Stresses applied by extractors
The projectile must be secured to the mouth of the CC to provide what? (3)
- Seal against moisture
- Prevent accidental removal
- Retention by the CC to allow gas pressure build up.
6 Methods of attaching SAA Projectiles to CCs?
P - Press fit I - Indenting S - Stabbing C - Coning C - Crimping C - Canneluring
** 4 Types of Bases to be used in SAA?
- Rimmed
- Rimless
- Semi-Rimmed
- Belted
** Method of ignition for SAA?
- Relies on a striker impinging on a cap containing sensitive composition
- Flame passes through flash holes to ignite propellant.