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| Science & Technology |
| Phalanx Has A Future |
| 2006-11-06 |
Dave D - Somebody listened to you! When tactical missiles are fired at close range the best U.S. weapon to shoot them down may be a good old-fashioned machine gun. Except there is nothing old-fashioned about Raytheon's Mark 15 Phalanx Close-In Weapons System, or CIWS. An article published Friday by Defense Industry Daily spells out the formidable capabilities of the Phalanx CIWS and explains why it is already the BMD weapon of last resort of the U.S. Navy and why so many other countries are interested in having it too. Interest in the Phalanx CIWS has spiked in recent months following the massive Katyusha rocket mortar bombardment of northern Israel by Hezbollah in their brief conflict this summer. The Katyusha attacks followed an escalating series of less intense and formidable, but still potentially dangerous, attacks against Israel by relatively low-tech, very short-range Qassem missiles fired by Hamas and its allies from with in Gaza, which Israeli forces evacuated in summer 2005. Both sets of attacks led to a revival of interest by U.S. congressional appropriators as well as by Israel in the development of laser weapon defenses against very short-range missile attacks. The Phalanx, however, has several striking advantages over laser BMD systems against short-range missiles. First, it is already operational and being produced and deployed in relatively large numbers. Second, it is the outgrowth of an already-mature technology, super-powerful, ultra-high speed machine guns have been a key element of the U.S. armed forces for decades. The awesome Gatling gun was used to devastating operational effect in Vietnam. The radar-guided, rapid-firing Phalanx CIWS is a worthy successor to the Gatling. The DID report Friday stated it can "fire between 3,000-4,500 20mm rounds per minute, either autonomously or under manual command, as a last-ditch defense against incoming missiles and other targets." "Phalanx uses closed-loop spotting with advanced radar and computer technology to locate, identify and direct a stream of armor piercing projectiles to the target," DID said. Defense Industry Daily noted that the Phalanx CIWS is already installed "on approximately 187 US Navy ships and is in use in 20 foreign navies." Third, the Phalanx CIWS is vastly more flexible than the ambitious and promising, but still experimental THEL laser systems we discussed in these columns on Aug. 24. DID cited Paul Gilligan, head of platform integration for Raytheon's British subsidiary, as saying that the Mark 15 Phalanx Block 1B upgrade was "vitally important, especially in the context of the evolving threats worldwide ... . It provides protection to ships and their crews against an increased number of threats including small, fast gunboats; standard and guided artillery; helicopters; mines and a variety of shore-launched, anti-ship missiles." DID said the MK 15 Phalanx Block 1B would "also be the base platform for the new SeaRAM short range anti-air missile system, in use by the USA, Germany, Korea, and others." The Phalanx is also believed capable of defending U.S. bases from mortar attacks, already a real concern in Iraq and a probable requirement in any significant land combat operations for the foreseeable future. DID noted that in June 2005, it had reported on the U.S. Army's land-based version of the weapon, unofficially but widely referred to as the R2D2 after the cute, but street smart and endlessly adaptable little robots in the "Star Wars " movies that they remarkably resemble. "Originally developed to defend U.S. bases against mortar attack, these adapted weapons could also provide defensive options against the kinds of rocket attacks encountered in Round 1 of Israel's recent war with Hezbollah," DID wrote. It noted that on Sept. 13, Raytheon received a contract for $129 million in funding for this system. This "suggests that rapid growth is on the way" in Phalanx CIWS production and further development, the article concluded. The success of the Phalanx CIWS is a demonstration of how even in the most ambitiously cutting edge fields of military technology, sometimes the best forms of defense employ simple, low tech principles combined with modern high tech ones. A gun employs far simpler principles than a laser or a rocket and is far less romantic. But even the most remarkable, high tech super-guns like the Phalanx CIWS far less likely to suffer development and operational failures than sci-fi like new super-weapons. Because they have been in production for years or even decades, they are usually far cheaper to produce en masse. The developmental costs have either already been paid long in the past or are minor compared with the ones for new weapons. There is already a potentially large arsenal of replacements and spare parts available for them. And there is already a large cadre of serving manpower in the U.S. armed forces experienced in operating and maintaining Phalanx guns. Finally, expanding use of the Phalanx CIWS in a BMD role against very short rang missiles also fits with the development philosophy that Lt. Gen. Henry "Trey" Obering has so successfully applied at the U.S. Missile Defense Agency of focusing resources on weapons systems that are already operational or show the promise of being so in the shortest periods of time, rather than funding far more ambitious but far off and speculative technologies. Therefore, for the Phalanx CIWS, the future continues to look bright. |
| Posted by:3dc |
| #9 In some ways a missile is an easier target than a manned aircraft since most missiles do not take evasive action. The few that are capable of evasive action do not do so actively (that is, in direct response to defensive fire). I had heard that cruise missiles have the ability for evasive maneuvers. I must assume that this amounts to selecting an alternate flight plan once defensive fire is encountered, as opposed to actually maintaining the same course whilst evading incoming fire. I was well aware of "leading" fire control (almighty thanks to Harold S. Black, inventor of the negative feedback loop), but just wondered if it attempted direct intercept or the "fly-through" model I proposed. With the proverbial hail of lead the Phalanx system puts out, it can toss up an impenetrable screen of fire. Another question: It would seem desirable to vary ever so slightly the outgoing trajectory of the system's fire so as to create a swath instead of a projectile stream. Are there some sort of "rockers" that gently sway the system, or is this naturally accomplished through flight variations induced by subtle barrel mis-alignment, ballasting, atmospheric turbulence or bullet tumble? Finally, is there any way to integrate the "Metal Storm" technology to this current arrangement? I know it would take a major redesign to swap barrels instead of bullets, but the enhanced fire rate would be tremendous. More than anything, its delightful to see a mature technology like this continue to live on well past its anticipated date. (Much like the hard disk drive, which has outlived all expectations by massive orders of magnitude.) PS: Thank you for the replies, AC and all. |
| Posted by: Zenster 2006-11-06 23:39 |
| #8 A problem I see with a land based Phalanx system is collateral damage from expended shells.Sea based systems expended shells fall harmlessly in the ocean.Laser type system may be better. |
| Posted by: Flomoter Ulolush5791 2006-11-06 23:27 |
| #7 "In the same vein, I would assume that these fire control systems aim to have the incoming projectile fly into the outgoing fire so that the missile intercepts the bullets as opposed to the other way around. Is this so?" Oops, forgot to answer your question. Actually, it is a combination of both, the system arranges for them to meet at a point common to both flight paths. This has been done automatically since the 1940s. In some ways a missile is an easier target than a manned aircraft since most missiles do not take evasive action. The few that are capable of evasive action do not do so actively (that is, in direct response to defensive fire). Piloted aircraft can of course evade actively though it is not easy and is highly range-dependent. The scenes in Top Gun of fighters dodging tracer streams were not fiction. It can be done, but not without a pilot, at least not yet. Contrary to popular impressions, many missiles are no faster than airplanes. For ballistic projectiles like Hezbollah's unguided rockets, the velocity is higher but not by as much as might be thought; and the flightpath is completely predictable even though it is not a straight line. The missile's real advantage is its small size, especially when seen head-on. |
| Posted by: Atomic Conspiracy 2006-11-06 23:05 |
| #6 Zenster Even a fairly primitive system like the tracked Vulcan could calculate lead angles automatically. It did this by sensing rate change from the optical sight and combining this with range, the latter provided by the boresighted radar dish. The optical sight was not automatically offset but the system provided an offset aim point. This was to allow the gunner to compensate for very slight errors in the system or to vary the aim point for a maneuvering, not just moving, target. These errors could result from atmospheric conditions or such things as barrel wear. Some systems compensate for these automatically but in those days it was easier just to do it by eye, with the gunner's own judgment interacting with the automatic system. The Vulcan system was very accurate, especially with 50 rounds per second coming out of it, but it lacked all-weather and night capability, and didn't have just a lot of range. |
| Posted by: Atomic Conspiracy 2006-11-06 22:47 |
| #5 I was told at AUSA a few weeks ago that the 7.62mm Dillon minigun put out more than 300lbs of thrust. Cool! I envision an automotive propulsion system that deters tailgaters!!! |
| Posted by: Zenster 2006-11-06 22:41 |
| #4 Zenster: Incoming usually has little or no bearing change. An exception would be an artillery or mortar shell on the way up in the first half of its trajectory. Still, the fire control stuff has been able to calculate lead for decades. |
| Posted by: Richard Aubrey 2006-11-06 22:28 |
| #3 Zenster, I would think the thrust from the firing gun is more of an issue than the brass/weight loss. I was told at AUSA a few weeks ago that the 7.62mm Dillon minigun put out more than 300lbs of thrust. |
| Posted by: Remoteman 2006-11-06 22:28 |
| #2 AC, I trust that the fire control systems are designed to "lead" their target as opposed to shooting directly at it. This is like photographing a moving target whereby you aim slightly in front of its trajectory so that it is in-frame once the shutter activates. In the same vein, I would assume that these fire control systems aim to have the incoming projectile fly into the outgoing fire so that the missile intercepts the bullets as opposed to the other way around. Is this so? SIDEBAR: I asked a friend of mine who was a Huey door gunner in Viet Nam whether the pilot had to make course corrections to account for weight loss, due to ejected lead and brass, once the minigun started firing. He confirmed this in no uncertain terms. |
| Posted by: Zenster 2006-11-06 22:15 |
| #1 The Phalanx and the "Gatling" gun to which this refers are not two different systems. The latter is apparently the Vulcan 20mm cannon, developed by GE in the late '40s and used in many many applications since. It has been the standard gun of US fighter aircraft since the late 50s. It really does operate on the Civil War era Gatling principle, with 6 rotating barrels, but the resemblance ends there. It is a component of Phalanx, which is an integrated system incorporating the mount and a very accurate and highly automated fire control system. I used the tracked Vulcan system in Vietnam. This was the Vulcan gun mounted on an M-113 APC chassis, with a rather rudimentary range-only radar to assist the gunner in tracking. It was intended as an air defense weapon but was devastatingly effective against ground targets. The Phalanx system is enormously more sophisticated but it uses basically the same gun. The British have a similar system, Goalkeeper, but this uses the GAU-8 30mm cannon developed for the A-10. To some extent, what matters here is not the gun itself but the fire control system, which must be autonomous and extremely fast-reacting. Some naval planners believe that a larger gun firing proximity fused ammunition would be more effective. The latest 57mm Bofors naval gun, for instance, fires up to 160 6 pound explosive shells per minute. This will fill the air with splinters, any one of which can do fatal damage to an oncoming missile. This is heavier than the Phalanx, but not by a tremendous amount, and it is still manageable for ground applications. |
| Posted by: Atomic Conspiracy 2006-11-06 21:37 |