Weapons Effects

Gary's Combat Vehicle Reference Guide

The kinetic energy projectile uses high velocity and mass to penetrate its target. Penetration depends directly on the projectile's velocity, weight, and the angle at which it hits.

Projectiles may have incendiary (tracer) pellets to aid in aiming and provide an incendiary effect. Incendiary projectiles can be used to penetrate a target and ignite its contents.

Types of KE projectiles include:

• Ball. Normally of a relatively small caliber (5.56 to 14.5 millimeters) and fired from pistols, rifles, and machine guns. The round's projectile penetrates soft targets on impact at a high velocity.
  
  
• Antipersonnel (APERS). Payload consists of a large number of hardened steel darts (flechettes). Detonation of the projectile sprays a cloud of flechettes into the target area. APERS rounds intended for direct fire artillery defense at close range are usually fuzed to detonate on muzzle action. Also known as flechette, beehive, or cannister.
  
  
• Armor piercing (AP). Designed to penetrate armor plate and other types of homogeneous steel. Armor piercing projectiles have a special jacket encasing a hard core or penetrating rod which is designed to penetrate when fired with high accuracy at an angle very close to the perpendicular of the target.
  
  
• Armor piercing discarding sabot (APDS). Consists of a sub-caliber penetrator rod encased in a light metal or plastic sabot. Centrifugal force and air pressure cause the sabot to discard on leaving the gun barrel. The penetrator rod is spin-stabilized.
  
  
• Armor piercing, fin-stabilized discarding sabot (APFSDS). Similar to APDS, but the penetrator is fin-stabilized.

The chemical energy projectile uses some form of chemical heat and blast to achieve penetration. It detonates either at impact or when maximum penetration is achieved. Chemical energy projectiles carrying impact-detonated or delayed detonation high-explosive charges are used mainly for direct fire from systems with high accuracy and consistently good target acquisition ability.

Types of CE projectiles include:

• High explosive (HE). Causes blast, fragmentation, and incendiary damage to the target. HE is the most common type of mortar and artillery round.
  
  
• High explosive anti-tank (HEAT). Designed to detonate a shaped charge on impact. At detonation, an extremely high velocity molten jet is formed. This jet penetrates a large thicknesses of armor, continues along its path, and sprays molten metal inside the target. If the jet hits an engine or ammunition, it may start a fire or cause an explosion.
  
  Rotation reduces the effectiveness of HEAT rounds, so spin-stabilized projectiles usually do not use HEAT warheads.
  
  HEAT rounds generally range in size from 60 to 120 mm. As a rule of thumb, a HEAT round can penetrate armor up to five times the warhead's diameter (e.g. a 100mm round can penetrate 500mm). Tanks, anti-tank weapons, and automatic cannons usually use these types of projectiles.
  
  
  This image shows how a warhead penetrates rolled homogeneous steel armor:
  1. Impact. The nose cone crushes; the impact sensor activates the fuze.
  2. Ignition. The ogive crush switch activates the electric detonator. The booster detonates, initiating the main charge.
  3. Penetration. The main charge fires and forces the warhead body liner into a directional gas jet that penetrates armor plate.
  4. After-armor effects (spalling). The projectile fragments and incendiary effects produce blinding light and destroy the target's interior.
  
  
• High explosive plastic (HEP). Flattens against the target on impact then explodes. The armor is not penetrated, but the shock wave knocks a scab off the inside of the armor plate which bounces around the interior of the target at high speed. Unlike HEAT, HESH projectiles have a secondary antipersonnel capability. Also known as high explosive squash head (HESH).

Flame weapons are characterized by both physical (flame and overpressure) and psychological casualty-producing abilities. The intense flame may also exhaust the oxygen content of inside air causing respiratory injuries to occupants shielded from the flaming fuel. Flame does not normally need to be applied with pinpoint accuracy to accomplish its mission. Flame weapons inlude flamethrowers, incendiary grenades, white phosphorus (WP) artillery shells, and fuel-air/thermobaric munitions.

Fuel-air (aka thermobaric) munitions disperse fuel into the atmosphere forming a fuel-air mixture that is detonated. The fuel is usually contained in a metal canister and is dispersed by detonation of a central burster charge carried within the canister. Upon proper dispersion, the fuel-air mixture is detonated. Peak pressures created within the detonated cloud reach 300 pounds per square inch (psi). The ability of thermobaric weapons to provide massed heat and pressure effects at a single point in time cannot be reproduced by conventional weapons without massive collateral destruction.

Flame weapons can be used against fortified positions, interior buildings, tunnels (to include subways and sewers), and open areas. They can also be used to control avenues of approach for personal and lightly armored vehicles. When employed properly, even if the round or burst misses, enough flaming material and overpressure enters the position or area to cause casualties and disrupt operations. Thermobaric munitions will provide a more effective and selective flame capability that is easier and safer to employ at all levels of tactical operations without the side effect of large area destruction due to uncontrolled fires.