by Tom Clancy
• Propulsion/Guidance—For the first time in a Western AAM, the AIM-9X will utilize an active thrust vectoring propulsion system, which will radically improve maneuverability. It appears that whatever design team wins the competition, the winner will make use of a Raytheon-designed and — developed fin control system known as Box Office. Composed of four tail-mounted maneuvering fins (there are no mid-body guidance fins as in AMRAAM), Box Office will make 60-G maneuvers possible for the first time on a U.S. AAM.
When all these components are integrated and the inevitable software bugs are eventually tracked down and stamped out, the AIM-9X will carry the proud Sidewinder tradition into a new century. With the will, the money, and an efficient management team, Dr. McLean's vision of an agile, lightweight, intelligent, and deadly missile will take to the skies on wings he could never have imagined back in that desert garage lab. Let's hope it works out; for without it, tomorrow's U.S. fighter pilots could be outgunned as well as outnumbered by systems made elsewhere.
AIR-TO-GROUND ORDNANCE
On the third day of the Persian Gulf War in 1991, General Charles A. Horner held a press conference in Riyadh, Saudi Arabia, to discuss how things were going. Known as the "four o'clock follies," these daily briefings were rather dull until General Horner started showing gun camera film (videotape, actually) from the various strikes of the first night of Desert Storm. A stunned hush, punctuated by an occasional grim chuckle or curse, fell over the "newsies" as they became the first witnesses of the revolution in the accuracy, range, and precision of modern airborne munitions. In clip after clip, the taped footage showed Iraqi command and control centers, bunkers, aircraft shelters, and other targets blowing up under a hail of guided bombs and other ordnance. Perhaps the most impressive demonstration of modern precision-guided munitions (PGMs) were a pair of clips from two F-117A Nighthawks. The target was the central communications and switching center in downtown Baghdad, known by Coalition planners as the "AT&T Building." Heavily overbuilt, it had a reinforced concrete roof designed to resist penetration and blast by normal general purpose (GP) bombs. It did not last long, though. The first F-117A arrived over the target and dropped a 2,000 lb./909.1 kg. laser-guided bomb (LGB) with a special penetrating warhead, blowing a huge hole in the reinforced roof of the building. Several minutes later, to allow time for the dust and other debris to settle (and thus not block the Nighthawk's thermal targeting system), another F-117, sighting on the edges of the hole in the roof, dropped two laser-guided bombs of its own into the hole from the first bomb and into the building's core shaft. Armed with GP warheads (blast and fragmentation), they blew out all four sides of the building, leaving it incapable of operations for the duration of the conflict. So specific are the characteristics of individual types of weapons that you now use one kind to blow open a hole and another type to fly through the hole to kill what you really want to be dead inside.Fighter pilots make movies. Bomber pilots make history! — OLD BOMBER PILOT BARROOM CHANT
That statement expresses a great truth about airpower. Nobody has ever won, or ever will win, a war by shooting down MiGs, Mirages, or whatever else the enemy may be flying against you. Airpower only helps win wars when you destroy things that are critically important to an enemy on the ground. Airpower's inherent limitation is staying power. Deadly machines like F-16s and B-1Bs simply cannot stay over a piece of battlefield forever. Therefore, it is vital that when a Joint Forces Air Component Commander (JFACC) commits his expensive and limited air resources, he must make them capable of delivering a "bolt from the blue." Not just deadly to what or who you want to destroy, but shocking and frightening to the survivors to the point where their morale is broken and their ability to fight effectively is destroyed. There is a story from Operation Desert Storm, about the commander of an Iraqi ground unit who surrendered with his entire unit several weeks into the aerial bombardment. When asked by his interrogator why he had surrendered, he responded, "It was the B-52s." When the interrogator pointed out that his unit had never been bombed by B-52s, the Iraqi officer replied, "That's true. But we saw units that had been." That is the ultimate goal of anyone using airpower: to so demoralize the survivors of bombing raids they don't even want to fight. They just give up. That's how you really make history.
Now it needs to be said that much of the effectiveness of the Desert Storm bombing campaign was due not only to dropping an overwhelming weight of ordnance on the targets in Iraq and Kuwait, but also to making sure that the right targets were getting hit by the right aircraft with the right munitions for those targets. For example, it would have been counterproductive for the huge B-52s, loaded with "dumb," unguided, general purpose bombs, to hit targets in downtown Baghdad. City blocks of buildings would have been flattened, causing thousands of civilian casualties, and the real targets, Saddam Hussein's hardened command bunkers, would have survived without harm. Moreover, because of the heavy air defense over Baghdad, we would have lost many aircraft just making the attempt. Colonel John Warden of the Air Command and Staff College is fond of saying, "Every bomb is a political bomb, with political costs, political benefits, and political effects." It is therefore doubtful that such a campaign would have ever been attempted by the Bush Administration given the political considerations of Coalition warfare and the sensibilities of the domestic media.
What actually happened was that Major General "Buster" Glosson and his "Black Hole" team developed a plan by which only aircraft capable of delivering precision-guided munitions (PGMs) would be allowed to bomb targets within the Baghdad metroplex. Downtown Baghdad was limited to weapons deliveries from F-117As and BGM-109 Tomahawk cruise missiles. As a result, while individual buildings and systems were demolished, the city of Baghdad was little touched by the campaign designed to help eject the Iraqis from Kuwait. This is the new face of airpower, where the right weapons are put on the right targets at the right time with the correctly planned weapons effects.
GENERAL PURPOSE BOMBS
History tells us that the first time aircraft were used to attack enemy forces on the ground was in January 1912, when an Italian second lieutenant named Giulio Gavotti, assigned to the Squadriglia di Tripoli and flying a crude biplane armed with four small improvised bombs, attacked Bedouin tribes-men in the towns of Taguira and Ain Zara in Libya. Since that time, the basic destructive mechanism of the general purpose (GP) bomb has changed relatively little: a tubular metal case, filled with explosive, fuzed to go off when it hits the ground, with some sort of stabilizing fins to make its fall to the target reasonably straight. Today, the USAF uses GP bombs that are true to that basic design, though there have been some recent changes of note.
The basic family of GP bombs used by the U.S. military (including the U.S. Navy and U.S. Marine Corps) is known as the Mark (Mk) 80 series. Though some of the World War II-vintage Mk 117 (a 750lb./340.9kg. weapon) and Mk 118 (a 3,000 lb./1,363.6 kg. weapon) bombs are still in use on platforms such as the B-52, the standard family of weapons used on U.S. aircraft today are the 80-series GP bombs. Designed in the 1950s by the famous Ed Heinemann, the Mk 80 series are what is called low-drag, general purpose (LDGP) bombs. Previously, the designers of GP bombs which were carried internally, or on subsonic aircraft, gave little thought to how much parasitic drag they added to an aircraft in flight. This became a major issue, though, with the design of Heinemann's classic A-4 Skyhawk attack bomber, which carried all of its ordnance externally on pylons. Thus, he and his design team began with a clean sheet of paper, and came up with the LDGP shape so familiar to military enthusiasts around the world. The cases are made from cast steel, with relatively thin (less than 1 in./2.5 cm.) walls. This provides one of the bomb's primary damage mechanisms: fragmentation. Being relatively brittle, the steel case expands into a shower of fragments, deadly out to a certain radius. As for the explosive, the current generation of 80-series weapons uses an explosive called Tritonal 80/20. It is composed of an 80 % mix of TNT with 20 % of the volume of an aluminum binder/ inhibitor. The resul
t is an explosive with slightly less explosive power than TNT but extremely stable in storage conditions such as ships and tropical sites. Also, it has a relatively high "cook-off" temperature, which makes the 80-series bombs able to survive for a time in conditions of flame, such as a shipboard fire. Just for added insurance against a cook-off, the U.S. Navy coats their bombs with an ablative coating to buy extra time to suppress the fire and "safe" the bombs.
A cutaway drawing of the Mk 84 2,000 lb./909.1 kg. General Purpose Bomb warhead.
Jack Ryan Enterprises, Ltd., by Laura Alpher
About 50 % of the weight of an 80-series LDGP bomb is explosive, with the rest being taken up by the bomb case, mounting/attachment lugs, fin group, and fuze(s).
Fuzes are more important than you might think, since most modern explosives require a sequence of deliberate actions to detonate. Fuzes have evolved a great deal since the delicate glass/fulminate-of-mercury devices used in the American Civil War to detonate ground and naval mines. Today, you choose a specific fuze based upon how and when you want a weapon to blow up. The current generation of fuzes are notable because of the variety of conditions that they can be adapted to function in and their ever-increasing reliability. This issue of reliability is critical. If you lug a bomb into defended enemy airspace and drop it with pinpoint precision on an enemy target, and it does not explode because of a fuze failure, then you have just wasted fuel, time, and maybe a multi-million dollar aircraft (as well as your life) for nothing. Some of the more common fuzes include:
Another item critical to successful employment of bombs is making sure that bomb fragments do not hit the attacking aircraft. This can happen to an aircraft doing low-altitude drops with LDGP bombs in a "slick" configuration. To avoid such accidents, "hi-drag" kits were developed to slow the bomb down and provide enough separation for the launching aircraft to safely escape the effects of the weapons it has just delivered. In World War II, these kits took the form of an attached parachute. During the Vietnam War, the spring-loaded fins of the Mk 15 "Snakeye" kit were used on the Mk 82. Today, the standard hi-drag or retard kit is an air-inflated bag, or "ballute," mounted in a special fin-group assembly attached to the rear of the bomb. There are two varieties: the BSU-49/B for the Mk 82 and the BSU-50/B for the Mk 84. After launch, the ballute kits channel the slipstream surrounding the bomb into the ballute, inflating it from the incoming rush of air. Their big advantage is their vastly greater reliability over the Mk 15 units, as air moving at hundreds of knots/ kph. tends to be a more consistent mechanical medium than folded springs.
Penetration Bombs
A constant of warfare in the 20th century is that concrete has been one of the great equalizers among combatants. Cheap, available, and relatively easy to work with, it can be fashioned into a variety of structures which can protect even delicate, high-value items like aircraft and dictators from the ravages of the elements and the forces of modern warfare.
Ever since the end of the Vietnam War, the USAF wanted a bomb that could penetrate bunkers, runways, and other reinforced concrete structures — a bomb that didn't weigh 3,000 to 4,000 lb./1,363.6 to 1,818 kg., and wasn't nuclear. In 1984, the Air Force Armament Division initiated Project Have Void and awarded a contract to Lockheed Missile and Space's Austin (Texas) Division to develop the new bomb, to be known as the BLU-109/B. Forged out of hardened 4340 steel, the BLU-109/B is essentially a large "masonry nail," shaped to plow through concrete, earth, and armor plate, and then explode on the other side of the protection. Weighing in at 1,925.5lb./ 875.3 kg., it has a specially shaped nose that is designed to help it "dig in" to flat concrete at high grazing angles. While the BLU-109/B can be dropped as a "dumb" bomb, when married to a Paveway III-series or GBU-15 guidance kit, it becomes a killing machine of incredible power and accuracy.
A cutaway drawing of the BLU-109/B Penetrating Bomb warhead.
Jack Ryan Enterprises, Ltd., by Laura Alpher
With its capability of destroying, or "holding at risk," something like 99 % of all the hardened targets in the world, the BLU-109/B has transformed the nature of air warfare. Saddam Hussein found this out the hard way back in 1991, when these bombs blew up virtually every hardened target in his country. When the Iraqi Air Force tried to take refuge in Yugoslav- and European-built hardened aircraft shelters that were thought proof against even near-misses by tactical nuclear weapons, they were opened up like tin cans by the penetrating power of the BLU-109/B. After a couple of days of such pounding, the remnants of the Iraqi Air Force ran for Iran.
Cluster Bombs
Early in the Vietnam War, American airmen began to encounter more and more targets that were spread out — so-called "area" targets made up of "soft," unarmored vehicles, supply dumps, and lightly built structures. What was needed was a weapon which would spread its effects over a known area, with a well-understood set of weapons effects. Rather than try to smear flaming napalm onto all of these things, something more modern was needed. That something was the cluster munition. Cluster bombs were not new. The idea dates back to World War II, when both fragmentation and incendiary cluster bombs were used for many purposes, but suffered from restrictive delivery profiles and the lack of predictable dispersal patterns for the small bombs (called "bomblets" or submunitions) carried in the cluster. To overcome these limitations, the U.S. Navy developed a new concept — the munitions dispenser.
The dispenser would be a "truck" for the load of submunitions, which would be dropped like a normal GP bomb onto the target area. At a preplanned altitude, the fuze (proximity or time delay from aircraft launch) would activate, causing the outer skin panels of the dispenser to break loose. Then another charge (usually compressed air or a small pyrotechnic charge) blasted the load of bomblets loose into a preplanned pattern, which would then fall onto the target.
The interior of an Iraqi hardened aircraft shelter showing the effects of a laser-guided BLU-109/B penetrating warhead following Operation Desert Storm. The pile in the middle of the floor is the concrete and filler from the ceiling, and what appears to be spaghetti is the steel reinforcement bars blown in by the force of the warhead.
Official U.S. Air Force Photo
The Navy's first effort, which began in 1963, centered around a dispenser called the Mk 7. When activated by an Mk 339 time delay fuze, the dispersion charge has the effect of scattering the submunitions in an elongated, doughnut-shaped pattern whose size is controlled by the release height of the bomblets. Each submunition has its own fuze, which detonates upon contact with a target or the ground. When the whole package was put together, it was known as the Mk 20 Rockeye II Mod. 2. It carried a load of 247 M118 anti-tank munitions that looked for all the world like sadistic hypodermic syringes, weighed in at some 490 lb./222.7 kg., and was an instant success with American aircrews when it reached Vietnam in 1967. Adopted by both the Navy and Air Force, it was particularly welcomed by aircrews tasked with attacking SAM sites and AAA gun emplacements, which were particularly vulnerable to the deadly rain of cluster munitions. This classic piece of aircraft ordnance has been so effective that some 27,987 Rockeye IIs were dropped on targets during Desert Storm, more than any other cluster munition used. At only $3,449 a copy (in 1991 dollars), it is quite a bargain by current standards.
With the early success of the Rockeye, the Air Force quickly jumped on the bandwagon and started development of its own cluster bomb dispenser, the Suspension Underwing Unit (SUU-30H/B). A total of 17,831 SUU-30-series weapons were delivered by U.S. aircraft during Desert Storm. This dispenser became the basis for a whole family of USAF CBUs. Some of the versions currently in use include:
As you can see, the variety of submunitions and weapons effects is numbing. Again, fuzing is as critical to successful employment of the SUU-30 family as it is for the 80-series GP bombs. If the dispenser opens too soon, then the density of submunitions will not be high enough to ensure destruction of the target. Similarly, if the canister opens too late, then the bomblets will not spread out enough to
cover the whole target. As might be imagined, it is a challenge for planners, ordnance technicians, and loaders to figure out the proper dispenser/submunition/fuze combination.
As good as the early CBUs were, they still imposed a number of restrictions upon fliers trying to deliver them. By the early 1980s the Air Force was beginning to realize that the early CBUs were shackled by a number of limitations in high-threat target areas. Most especially, the aircraft delivering them had to actually overfly the target in "laydown" delivery profiles, exposing them to ground fire. Thus, a new series of submunitions was developed by the Air Force, with a larger dispenser that would get enough of them onto a target array to be useful. And so was born the SUU-64/65 Tactical Munitions Dispenser (TMD).
The TMD is a 1,000 lb./454.5 kg.-class weapon, with three versions currently in service with the USAF. All three share the basic TMD dispenser components, with only the submunition load and other minor details differentiating them. Starting at the front is the optional FZU-39/B proximity fuze, which is designed to tell the TMD its exact altitude at all times. There is also a time delay fuze, which can be used by itself, or in conjunction with the FZU-39/B. Just aft of the nose/fuze section is the cargo section where the submunitions are packed. This is a tubular body section, with equipment designed to cut the body into thirds when the submunitions are ready to be deployed. This is topped by a structure called a strongback, where the mounting lugs are attached. At the rear is a tail assembly, with spring-loaded guidance fins designed to stabilize the entire TMD assembly.