Service ammunition. Ammunition for combat use. This    ammunition    is    approved    for    service    use.    It contains  explosives,  pyrotechnics,  or  chemical  agent filler.   The   propellant,   if   required,   is   of   service   or reduced   charge   weight.   Service   ammunition   is   also called  tactical ammunition. Warhead.  The  part  of  ammunition  containing  the materials intended to inflict damage. The explosives in warheads are called the  payload. Airborne   stores.   Items   that   are   NOT   normally separated  from  the  aircraft  in  flight.  A  partial  list  of these items includes tanks, pods, and non-expendable training  weapons.  Targets,  racks,  launchers,  adapters, and detachable pylons are also included. Q8-1. What     aircraft     equipment     uses     cartridge- active devices (CADs)? Q8-2. Define the term incendiary. Q8-3. What are airborne stores? THE FUNDAMENTALS OF EXPLOSIVES LEARNING  OBJECTIVE:  Recognize the  fundamental  concepts  of  explosives, the    potential    hazards    associated    with weapons,     and     the     identification     and marking of ammunition. You    should    know    the    difference    between    an explosive and an explosion. An explosive is a material that  is  capable  of  producing  an  explosion  by  its  own energy. There  are  many  definitions  of  an  explosion.  Dr. Tenney L. Davis gave us the only simple definition: an explosion is "a loud noise and the sudden going away of things from the place where they have been." Another definition  states  "an  explosion  is  a  rapid  and  violent release     of     energy,     not     necessarily     involving     an explosive substance." For example, in the explosion of a boiler, the water is not an explosive substance. In   this   chapter,   an   explosion   is   defined   as   "a chemical  decomposition  or  transformation,  with  the growth  of  heat  and  the  formation  of  decomposition products, sometimes producing gas." All explosives in military use produce gas, so this definition is correct, though a chemist might not agree. If ammunition is to function at the time and place desired, you must use the right type of explosives. Each has a role, either as a propellant or as a bursting charge. Explosives  suitable  for  one  purpose  may  be  entirely unsatisfactory for another. For example, the explosive used to burst forged steel projectiles is unsuitable for ejecting  and  propelling  the  projectile.  Normally,  the more  sensitive  the  explosive,  the  smaller  the  amount used. Similarly, the explosives used in initiators, such as primers and fuzes, are so sensitive to shock that only a small quantity can be used safely. HIGH AND LOW EXPLOSIVES There are two general classes of military explosives—high explosives and low explosives. Each is  classified  according  to  its  rate  of  decomposition. High and low explosives may be further classified by their  reaction,  composition,  or  service  use.  However, only the two general classes, high and low, are covered in this chapter. High Explosives High  explosives  are  usually  nitration  products  of organic  substances.  They  may  contain  nitrogen  and inorganic   substances   or   mixtures   of   both.   A   high explosive  may  be  a  pure  compound  or  a  mixture  of several    compounds.    Additives,    such    as    powdered metals,   plasticizing   oils,   or   waxes,   provide   desired stability and performance characteristics. A high explosive is characterized by extremely fast decomposition   called   detonation.   A   high   explosive detonates   almost   instantaneously.   The   detonation   is similar  to  a  very  rapid  combustion  or  a  rupture  and rearrangement  of  the  molecules  themselves.  In  either case,  gaseous  and  solid  products  are  produced.  The disruptive effect of the reaction makes some explosives valuable   as   a   bursting   charge.   This   bursting   effect prevents    its    use    in    ammunition    and    gun    systems because the gas pressures formed could burst the barrel of a weapon. Low explosives Low    explosives    are    mostly    solid    combustible materials that decompose rapidly but do not normally explode.   This   action   is   called deflagration.   Upon ignition  and  decomposition,  gas  pressures  develop  to propel something in a definite direction. Ammunition, gun   systems,   and   some   missiles   use   this   type   of explosive.    The    rate    of    burning    is    an    important characteristic,    which    depends    on    such    factors    as combustion   gas   pressure,   grain   size   and   form,   and composition. Under certain conditions, low explosives may react in the same manner as high explosives and explode. 8-2