Page 231 - NAVAL SCIENCE 3 TEXTBOOK

NAVAL WEAPONS AND AIRCRAFT 237

the system will automatically ce<1se firing and begin searching rotating band body ogive
for another target. 1\ follow-on CI\'VS system to Phalanx called
the Sea-ltlIl1 L1ses a magazine of eleven rolling airti·ame missiles
(RAM) vice a Gatling gun to engage close-in t<1rgets. It is installed
in littoral comb<1t ships.
Types of guns on tod<1Y's naval aircraft will be discussed in the
following chapter. base bourrelet
bUrster charge bourreiel nose fuze
Gun Ammunition
The principal components of a full round of gun amlllunition
arc a propellillg chillge (propellant) and a projectile. The propelling
charge provides the thrust th<1t ejects the projectile at the desired
velocity from the muzzle of the gun. The propelling charge asselll- rotating band projeclile body
bly includes an ignition system, the propellant, and the container.
thick walls nose cap windshield
The payload or projectile assembly includes the detonating fuse,
the booster, and the burster charge.
In a naval gun, the propellant charge is packed behind the pro-
jectile, either in bags or in metal cartridge cases. If the propellant
is packed in bags, the amlllunition is called bag allll/lllI/itio/l; if it
base cavity for burster cavity
is packed in a case, it is called case allll/llllli601l. The huge 16-inch
detonaling fuze
gUllS of the old retired battleships used bag ammunition, but all
Diagrams of a naval gun projectile, showing the external features
modern naval guns on active ships today use either semifixed or
(top), the internal construction of an antiaircraft common projectile
fixed case alllmunition. SClllifixed amlllunition refers to a round (middle), and the internal construction of an armor-piercing projec-
tile (bottom).
that consists of a projectile and a separate case charge loaded one
after the other. This type of round is lIsed in most 5-inch gUllS.
Fixed ammunition refers to a round in which the projectile and
lant train or series is called a prilller or dctOllfltor; it produces a hot
powder case are permanently attached. as with a rifle cartridge.
flame that sets olf the next stage, called the iglliter or booster. The
Such ammunition is used in 3-inch and smaller guns.
igniter, in turn, sets off the main burster charge.
Propellfllits are chemical compounds that burn at a rapid rate
rather than detonate or explode. The initiating stage in a propel-
Gun Projectiles
The projectile is the part of a round that is expelled at high vcloc-
ity from the gun bore by the burning propelling charge. Projectiles
used in slllall weapons often consist of solid metal; projectiles lIsed
in larger gUllS, however, are assemblies of several components. The
three main parts of a projectile are its metallic body, the fuse that
sets off the main charge. and the explosive burster charge. A solid
bullet damages by impact aione. Naval high-explosive projectiles
inflict damage primarily by blast and fragmentation. This type of
projectile is designed to break Up into many fragments of specific
dimensions upon detonation.
Projectiles are cylindrical ill shape, with pointed noses called
ogil'cs. Such a shape makes the projectile stable as it spins about its
long axis in flight, with a minimum resistance to air. As previously
mentioned, the bores of modern naval guns arc rifled in order to
impart this spin to the projectile as it travels the length of the bore.
The Phalanx close-in weapon system is a 20-mm fully automatic gun
system designed as a ship's last-ditch weapon against antiship cruise Various projectiles have different designs, because the targets
missiles. The gun is a six-barrel Vulcan Gatling gun capable of firing the), are intended for difter in character. There are three generai
three thousand rounds per minute to a range of about 1 mile. (Philip classes of projectiles: penetrating, fragmenting, and special purpose.
McDaniel)