R2D2 with Attitude: The Story of the Phalanx Close-In Weapons System (CIWS) byRobert H. Stoner, GMCM
(SW) (Ret) Phalanx is a Close-In Weapons System (CIWS) designed as a last chance, point defense, automated gun system designed to destroy in-bound anti-ship cruise missiles.� Phalanx is a design from General Dynamics Corporation, Pomona Division.� Its current manufacturer is Raytheon Company.� Phalanx is found aboard every class of U.S. Navy ship,
Coast Guard cutters of the Hamilton, Legend, and National Security classes,
and in the navies of 23 allied nations. Phalanx has been nicknamed �R2D2� after the famous android from the movie �Star Wars� by people in the U.S. Navy.� Royal Navy sailors call it them �Daleks� after the aliens in the long-running �Doctor Who� television series.�� In recent years, the U.S. Army has been testing a land version of Phalanx called �C-RAM� for Counter-Rocket, Artillery, and Mortar system.� The C-RAM is a Phalanx module with an on-board generator and control station mounted on a low flatbed trailer. History
On 21 October 1967, during the Arab-Israeli �Six Day War�, three Soviet-designed SS-N-2 �Styx� missiles from two Egyptian-manned, Soviet-supplied Komar-class missile craft attacked and sank the Israeli destroyer INS EILAT (K40) off Port Said, Egypt.� EILAT was the ex-HMS ZEALOUS (R39), a former British WW2 destroyer of the �Z� class.�� The sinking of the EILAT caused a major panic among the world�s navies and kicked point-defense systems into high gear. �Until the EILAT�s sinking, fleet air defense had concerned itself with the destruction of attacking manned aircraft.� Defeating a small, fast, low-flying threat represented by an unmanned cruise missile was a completely different story.� Worse, these anti-ship missile (ASM) systems could be fielded and operated by small countries with devastating effects. Above: The attacked � INS EILAT (K40) [ex-HMS
ZEALOUS (R39)] as she was at the time of the Arab-Israel Six Day War. (Photo:
Israeli Navy) Below: The attackers � two Komar missile attack
craft of the United Arab Republic (Egyptian) Navy.� (Photo: UAR Navy) Above: The attack on EILAT of 21 October 1967 � from
the Egyptian newspaper "Al Gomhoreya" � with English
captions from the Arabic.� (Art: "Al
Gomhoreya" via Bob Stoner) Below: A Soviet SS-N-2 Styx missile on its
transporter.� The solid rocket booster
is not fitted.� Styx is a large bird at
21.8 ft (6.6m) by 8.2 ft (2.5 m) by 2.6 ft (0.8 m); launch weight is 5,562 lb
(2,523 kg); warhead is 1,050 lb (480 kg); speed is 1.3 Mach; min range is 4
miles (8 km), max range is 40 miles (80 km).��
(Photo: Russian Navy) The Navy approached ASM defense as both a surface-to-air (SAM) missile problem and as a gun problem.� The first SAM system specifically designed to deal with the ASM problem was the Basic Point Defense Missile System or BPDMS.� The BPDMS was first tested aboard USS BRADLEY (FF-1041) in February 1967.� The BPDMS used eight modified RIM-7E Sea Sparrow missiles in an eight-cell Mk 25 launcher that was a scaled-down version of the Mk 112 launcher for the ASROC (Anti-Submarine Rocket).� The Mk 115 fire control radar system provided targeting for the RIM-7E.� Missile range was about 10 to 16 miles with a 65-pound high explosive, continuous rod warhead. Below: The Basic Point Defense Missile System
(BPDMS) was composed of the Mk 115 fire control director and Mk 25
launcher.� The Mk 115 director was a
manned system as shown in this photo taken aboard USS DWIGHT D.� EISENHOWER (CVN-69). �(Photo: U.S. Navy)� Above: The Mk 25 launcher for Sea Sparrow aboard the Knox-class frigate USS JOSEPH HEWES (FF-1078).� (Photo: Tom Oshgan)� Meanwhile, General Dynamics Corporation, Pomona Division, started with the Army�s self-propelled M163 Vulcan Air Defense System (VADS) to produce an automated version for naval service.� The new weapon was called Vulcan-Phalanx (shortened to Phalanx).� The prototype Phalanx was installed aboard USS KING (DLG-10/DDG-41) in 1973 for evaluation.� Another prototype CIWS was used in tests conducted aboard ex-USS ALFRED A. CUNNINGHAM (DD-752).� Several different kinds of missiles were fired at CUNNINGHAM; all were shot down.� Full operational and evaluation trials were performed aboard USS BIGELOW (DD-942) in 1977. Phalanx met and exceeded all maintenance and reliability requirements.� The first production units of Phalanx were installed aboard USS CORAL SEA (CV-43) in 1980.� Installation aboard noncombatant ships began in 1984.� Block 1 was deployed aboard USS WISCONSIN (BB-64) in 1988.� Block 1B was deployed aboard USS UNDERWOOD (FFG-38) in 1999 and was operational aboard USS TAYLOR (FFG-50) in 2000. Above: The M163 Vulcan Air Defense System (VADS) as installed on the M113 armored personnel carrier.� This M163 VADS of the 24th Infantry Division is shown at the Fort Irwin National Training Center on 1 November 1988.� (Photo: U.S. Army)� Below: The very first Phalanx prototype aboard USS
KING (DLG-10/DDG-41).� The gun was
located on the fantail of the ship as shown in the insert.� Above: A production Phalanx Block 1A firing.� Note the enlarged ammunition drum and different gun support� yokes that support the gun and radome.� (Photo: U.S. Navy) The Falklands War between the UK and Argentina [1982] raised further questions about the effectiveness of ASM defense.� Accordingly, the latest version of the Mk 15 Mod 0 Phalanx, called the Block 0, was installed aboard the test ship ex-USS STODDARD (DD-566) in November 1983.� A year long round of real world tests against all kinds of targets � including live warheads � were undertaken.� Lessons learned from these tests were incorporated into the Block 1 version of Phalanx.� From June 1985 through early 1990 extensive tests against Block 1 Phalanx were conducted aboard STODDARD that led to Block 1, Baseline 1 and 2 improvements.� These tests led to the development of the Block 1A variant that introduced an updated computer with software designed to engage targets doing high-G and diving maneuvers.� Design
The Phalanx uses the M61-series Vulcan Gatling gun
rotary cannon firing the 20x102mm round.�
The M61-series gun has six barrels; Block 0 and 1A barrels are 76
calibers (1,520mm or 60 inches) long and Block 1B barrels are 99 calibers
(1,980mm or 78 inches) long.�� The
ammunition has electric primers and is carried in a drum below the gun.� The drum uses a helical screw to feed ammunition
to the gun.� The drum has a capacity of
990 or 1,550 rounds.� Live ammunition is carried to the gun by a linkless feed system; fired cases are returned from the gun for storage in the drum by the same linkless feed system.� No ammunition links are used while the gun is in operation to assure a smooth feed cycle. Above: The timeline of Phalanx development beginning
with the Mk 15 Mod 0 Block 0.�
(Artwork: Raytheon) On Block 0
reloading of the drum can take between 10 to 30 minutes if loaded from
prelinked ammunition boxes.� Block 1
and later guns use a preloaded ammunition loader/unloader cart.� The loader/unloader cart uses linked live
ammuntion and a drum loader adapter.�
The linked ammunition is connected to the adapter (yellow part in the
photos) that attaches to the end of the drum.�
The adapter turns the screw feeder of the drum to bring fired cases to
the mouth of the drum.� Live rounds
that enter the adapter have their links stripped off.� A feed chute moves the delinked live
ammuntion to the bottom of the drum where it enters to begin the reloading
cycle.� The stripped links are
recycled.� The adapter relinks them to
the fired cases as they come out of the end of the drum.� The relinked empty cases are stowed aboard
the cart or ammunition boxes. Above: Loading Mk 149 Mod 4 ammunition into the Phalanx
drum on USS GEORGE WASHINGTON (CVN-73) in January 2004.� The live ammunition is going in and the
fired cases are coming out � both linked.�
The split line of the discarding sabot projectile is very prominent in
this shot.� (Photo: U.S. Navy)� Above: A closer look at loading Mk 149 Mod 4
ammunition into the Phalanx feeder drum.�
The yellow part is the delinker/linker adapter for the drum. �(Photo: PH1 Tina M. Ackerman) Below: A sectioned view of the Mk 149 Mod 4
cartridge.� (Artwork: General Dynamics
Corp.) The 20x102mm
ammunition for the Mk 15 Mod 0 uses a heavy metal penetrator to knock down
aerial targets.� Mk 149 or Mk 244
projectiles have no explosive filler.�
The Mk 149 Mod 0 and Mod 2 projectiles use a depleted uranium
sub-caliber penetrator.� The Mk 149 Mod
4 and Mk 244 Mod 0 rounds use a tungsten or tungsten alloy steel
penetrator.� Mk 149 Mod 4 rounds use a
red tracer element.� Range of the Mk
149 Mod 4 projectile @ 45 degrees is 6,000 yards (5,500 meters); maximum
effective range is 1,625 yards (1,490 meters). Above: The M61-series gun uses the 20x102mm cartridge
(left).� It is shown compared to the
20x110mm cartridge used by the M3, M24, Mk 12 and Mk 16 20mm machine guns of
the USAF and USN.� (Photo: Anthony G.
Williams) Because the
20mm projectile of Phalanx contains no explosive filler, the kill mechanism
for this round is either warhead detonation of the target (a hard kill) or
aerodynamic disintegration of the missile airframe caused by the high-speed
slipstream over the damaged areas (a soft kill).� The Mk 244 Mod 0 cartridge is known as the
ELC (Enhanced Leathality Cartridge).�
It has a more aerodynamic tungsten alloy penetrator that gives an
increase in effective range.� Muzzle
velocity is 3,650 feet per second (1,113 meters per second) for the Mk 149
cartridge. The Mk 15 Mod 0
Phalanx is broken down into the M61A1 20mm rotary cannon and the Mk 72
mount.� The Mk 72 mount contains the
hydraulics, pneumatics, computers, power drives, power supplies, and coolant
water pumps. Above: The anatomy of the Mk 15 Mod 0 Phalanx: (1) Ku band search radar; (2) Ku band tracking and gun laying radar; (3) M61A1 20mm Gatling-type rotary cannon; (4) helical feed ammunition drum and linkless feed system; (5) elevation power drive; (6) computer modules; (7) hydraulics, pneumatics, train power drive, power supply, and cooling water pump.� (Artwork: General Dynamics Corp. via Bob Stoner)� � Upgrades The Mk 15 Mod 0
is the base model of Phalanx.� Blocks 0
and 1 have a hydraulic drive for the M61A1 gun that produces a cyclic rate of
3,000 rounds per minute.�� Block 0 guns
have a 990 round magazine.� Block 1
guns have a 1,550 round magazine. �Block 1A and 1B have 1,550 round magazines
and a pneumatic gun drive that produces a 4,500 rounds per minute cyclic
rate.� Block 1B guns use an
electro-optical sighting system and have anti-air and anti-surface
capabilities lacking in Block 0 through 1A. ���
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