Intermediate Ballistics PDF

INTERMEDIATE BALLISTICS  AIM To acquaint the class with Intermediate Ballistics in Small Arms  PREVIEW PART III - PART I - BLAST METHODS OF SUPPRESSION...

INTERMEDIATE BALLISTICS  AIM To acquaint the class with Intermediate Ballistics in Small Arms  PREVIEW PART III - PART I - BLAST METHODS OF SUPPRESSION PART II - FLASH  DISTR OF ENERGY Energy of 45 % Propellant Gases Roughly 75% of avbl energy passes Motion of through muzzle 30 % Projectile Heat Retained by 25 % Barrel  INTERMEDIATE BALLISTICS Heat Blast Pressure Motion Flash BLAST PART - I  SHOCK WAVE  Abrupt change in pressure, temp & density of the medium forms a shock wave  Types – Blast Shock wave and Bottle Shock  BLAST SHOCK WAVE  Release of high pressure gases from muzzle cause turbulence  The resultant pressure waves radiate at the speed of sound as noise  Waves travels both sides i.e away from the muzzle & towards it  The outgoing noise primarily takes the form of an abrupt increase in pressure known as a ‘Blast Shock Wave’  It is heard as a sonic bang SHOCK WAVES FORMED BLAST SHOCK  BOTTLE SHOCK  Quasi static shock wave  Shaped like a bottle  Size depends on outgoing gas velocity SHOCK WAVES FORMED BLAST SHOCK MACH DISC BOTTLE SHOCK BARREL SHOCK MUZZLE GAS FLOW FIELD DURING FIRING PRECURSOR MAIN BLAST BLAST FD FD - - AFTER BEFORE PROJECTILE PROJECTILE EXITS EXITS  PRECURSOR BLAST FIELD  Shock wave formed just ahead of the projectile  Released as a near spherical precursor shock  Flowing air velocity incr - small bottle shock formed  PRECURSOR BLAST FD PRECURSOR BLAST SHOCK PRECURSOR MACH DISC BOTTLE SHOCK PROPELLANT GAS LEAKAGE PRECURSOR BARREL SHOCK  MAIN BLAST FIELD  Projectile emerges – High pressure propellant gases released  Generates a powerful blast shock called the Main Blast  PHASES OF MAIN BLAST FIELD Phase I Initial Ph Expansion Phase II of Blast Fd Phase III Final Ph  PHASES OF MAIN BLAST FIELD  Projectile emerges Initial  High pressure propellant gases released Ph  Blast fd is highly non spherical  Distorted by projectile & high velocity gases Expan-  Propellant gases rapidly expand sion Ph  Velocity of gases > speed of projectile  Addl acceleration to projectile  New large barrel shock & mach disc are formed Final  Velocity of gas decr - bottle shock shrinks & withdraws Ph  Supersonic projectile- passes through blast field  Main Blast fd catches up with precursor blast fd  SHOCK WAVE : INITIAL PHASE  The projectile emerges from the muzzle  High pressure propellant gases released into the atmosphere  Generates a highly non-spherical powerful blast shock  INITIAL PHASE MAIN BLAST PRECURSOR SHOCK BLAST PROJECTILE STERN SHOCK REMNANTS OF BARREL SHOCK PRECURSOR MACH DISC & BARREL SHOCK  STERN SHOCK Shock produced by the gases on striking the base of the projectile in vicinity of the muzzle  EXPANSION OF THE BLAST FIELD  Initially the blast field is highly non spherical  Distorted by the presence of the projectile & high velocity flow of gases  The propellant gases rapidly expand  Accelerates to velocities much greater than that of the projectile  EXPANSION OF THE BLAST FIELD BLAST SHOCK PRECURSOR BLAST MACH DISC PROJECTILE PRIMARY BARREL SHOCK SHOCK  FINAL PHASE OF THE BLAST FIELD  A new large barrel shock & mach disc are formed  As velocity of outflowing gases reduces, the bottle shock shrinks & withdraws within the barrel  If the projectile is supersonic, it will in the meantime, pass through the blast field  The main blast shock tends to catch up with the precursor blast shock  FINAL PHASE OF THE BLAST FIELD PRIMARY MACH DISC SHOCK BASE SHOCK BARREL SHOCK PROJECTILE WAKE MIXING OF PROPELLENT GASES & AIR IN TURBULENT FLOW  BASE SHOCK  Shock produced once the base of the bullet crosses the blast shock  PROJECTILE WAKE  Turbulence created behind the base of the projectile  Created due to the high speed of the projectile  Vacuum (low pressure area) behind the base PROJECTILE WAKE FINAL PHASE OF THE BLAST FIELD SHOCK WAVES FORMED FLASH PART - II FLASH PART - III  FLASH  Visible light emitted in the vicinity of the muzzle  Hot propellant gases chemical reactions with the surrounding air  FLASH Pre flash Primary flash Intermediate flash Secondary flash Incandescence  PRE FLASH  Hot gases & particles leaked past the projectile  Also known as muzzle glow  PRIMARY FLASH  After projectile exits the muzzle  High temp of the propellant gases emit visible radiation  INTERMEDIATE FLASH  Gases rapidly expand & cool they emit a faint muzzle glow  Gases recompressed as they pass through the mach disc  The consequent high temp produces Intermediate Flash  SECONDARY FLASH  Brightest and appears farthest from the muzzle  Produced by ignition of hot combustible gases with atmospheric oxygen  Absent in small arms - temp & density of gases is inadequate  INCANDESCENCE  Hot particles & remnants of burning propellant may appear as a long streak of light in the wake of the projectile FLASH  FLASH INCANDESCENCE PRIMARY MIXING OF PROPELLANT FLASH GASES & AIR IN PRE FLASH TURBULENT FLOW INTERMEDIATE FLASH - RECOMPRESSION ON PASSAGE THROUGH MACH DISC METHODS OF PART - III SUPPRESSION  BLAST SUPPRESSION  Blast shock from small calibre weapons can be suppressed by using attachments to the muzzle  They alter the flow of the escaping gases to reduce the intensity of muzzle blast  Sound suppressors are also called sound moderators or silencer METHODS OF BLAST SUPRESSION Blast absorption Blast dissipation Blast containment & controlled release BLAST ABSORPTION STEEL WOOL BLAST DISSIPATION BLAST CONTAINMENT & CONTROLLED RELEASE FLASH SUPPRESSION  FLASH SUPPRESSION  Flash is undesirable  At night will hamper firer’s vision  Will give away the firer’s posn to the en METHODS OF FLASH SUPPRESSION Muzzle device Propellants Use of propellant additives  MUZZLE DEVICES  Surrounds the primary flash  Hides flash from sides  Disperses & breaks up the bottle shock & mach disc thereby reducing intermediate flash Slotted-Negev LMG Perforated-5.56 mm Bar-Sig Sauer 716 Insas Rif  ADDITIVES/ INHIBITORS  Inhibit hydrogen oxygen combustion  Potassium & Sodium Salts Potassium sulphate Potassium nitrate Potassium cryolite Sodium cryolite  Reduced power, Incr smoke and fouling  PROPELLANTS & INTERMEDIATE BALLISTICS  Burning property  Blast Percussor blast shock - incr Degressive ABP Main blast shock - incr and Neutral peak pr delay  Flash Only for SA Progressive Pre Flash - incr Primary flash - incr Incandescence - incr Less  Type of propellant Precursor Blast Shock Single Base Main Blast Shock Pre Flash Double Base - more powerful Primary Flash Intermediate Flash More Triple Base - nitroguanidine (cooling eff, more smk) CONCLUSION ? JAI HIND