Long before Paveway laser-guided bombs blew up the bridges in North Vietnam, the U.S. Air Force experimented with radar-guided bombs. In a 1987 case study "The Quest for a Surgical Strike: The Air Force and Laser-guided Bombs," Air Force historian David R. Mets traced the precursors to the Paveway weapon guidance kits. The following is excerpted from that case study with permission. [to the original site www.airspacemag.com [Ed.]]

German Guided Bombs

By 1943, the war had been unkind to the Italian armed forces. They had been battered by the British in North Africa and by the Greeks and Albanians in the Balkans even before the Americans arrived with the 1942 TORCH landings. Since then, the remnants of the Italian Army in Africa had been held in prisoner of war (POW) camps at Tunis, and their brothers driven from Sicily. The Italian Navy had suffered much the same fate as Mussolini's empire was tottering. Clearly, most of the Italian people and many of their leaders wanted out. Secret negotiations were undertaken with General Eisenhower providing for the Italian capitulation simultaneously with the September Allied landings on the Italian mainland. A part of the agreement was that the remainder of the Italian fleet, still a potentially powerful force, would set sail under a pretense and go to Malta where it would be turned over to the Allies.

The Germans were not as surprised with the Salerno landings as they had been with Sicily. They were suspicious and not at all confident in the loyalty of their Italian allies. Still, the Italian sailors at La Spezia persuaded their German friends that they would help attack the Allied landing ships. Late on the afternoon of 8 September 1943, the main units, led by the 42,000-ton battleship ROMA, weighed anchor and steamed southward. Soon they were joined by the supporting cruisers and destroyers out of Genoa. The skeptical Germans, however, shadowed the great fleet with Luftwaffe airplanes. Hitler's airmen had orders to support the Italians if indeed they did attack, but to assault the ROMA and her escorts if they made any move to abandon the fight.

When the Germans decided that their Allies were defecting, they were ready with a special bomber unit temporarily based in Sardina. The airplanes themselves were not impressive--DO 217s, mediocre derivatives of the "Flying Pencils" that were proved inadequate in the Battle of Britain. The unit, led by Major Bernard Jope, overtook the Italian Navy just south of Corsica. He approached at altitudes above 15,000 feet, safe from most anti-aircraft fire. The Italians spotted the approaching Luftwaffe but only tardily recognized them as attackers. The Italian sailors went into the defensive tactics that had temporarily proved successful for the Japanese at Midway the previous year (throwing their rudders hard over) certain that most of the bombs coming down from high-altitude could not hit a speeding target in a hard turn. Were the Germans to either dive on the ROMA or descend for a torpedo attack, both sides knew that the problem for the Italian gunners would be greatly simplified. Neither the azimuth nor the elevation of the airplanes would be changing. All the gunners would have to do would be to hold their barrels steady and keep shooting until the attackers flew into the range of the projectiles.

But Jope's pilots did not descend. As soon as their weapons were released, they pulled back the Throttles and threw down the airplanes' flaps, and maintained their altitude. They did this because the weapon was no ordinary bomb. Rather, it was the "Fritz X," and it was necessary to get it out in front of the airplane so that the bombardier could see the flare in its tail. Once he had spotted it, he could then use his joystick, much like the one in small airplanes, to fly the bomb toward its target far below. Using his own eyes as sensors, the bombardier would automatically send signals via radio merely by moving his stick. The receiver in the tail of the weapon passed these right-left and up-down instructions to the control surfaces of the bomb. Too, the bomb had a gyroscopic system the transmitted stabilizing signals to the control surfaces to prevent rolling.

The first Fritz launched at the twisting ROMA was directed by Sergeant Oscar Huhn. It was necessary for the pilot to maintain nearly straight and level flight but at 18,000 feet they were not all that vulnerable to the anti-aircraft fire being put up by the ships. Even at its terminal speed of 625 mph, it would take the Fritz X the better part of a minute to make its descend. But for all the ROMA's twisting and turning it could not escape. Huhn radioed his instructions to the bomb, and it pursued the ship. Finally, at 1540 the bomb smashed into the foredeck of battleship. The warhead as fabricated from an armor-piercing bomb, and the weight of the weapon exceeded 3,000 pounds. Since it needed a heavy metal casing to penetrate the armored decks of the battleship, only a fraction of that could be explosive. Necessarily, it had a delayed action fuze to permit the weapon to get inside the target before its 660 pounds of explosive detonated. The first Fritz went all the way through the ROMA and detonated immediately beneath its hull, and the second one detonated within her vital spaces. A fire was started and much water was coming aboard. The situation was desperate and the Italian sailors knew they would have to abandon their vessel. But the fire spread to the magazine too fast, and the explosion took her to the bottom with more than a thousand of her crew, including the admiral in command of the task force. Sergeant Hun got the Iron Cross for his precision work.

About the same time the Luftwaffe used another weapon in combat that was not much different from the Fritz X in principle. Thousands of the Fritzes had been manufactured, but only 200 or so were employed against the Allies. The similar weapon was the Henschel 293 which was smaller and not designed for the penetration of armor. It had a rocket assist that extended the standoff range and at the same time eliminated the need for the delivery aircraft to slow its speed immediately after launch. Even before the sinking of the ROMA, this latter weapon was used with some success against commercial and other thin-skinned ships in the Bay of Biscay. This had a temporary impact on the U-Boat war, but for a long time the Germans denied themselves the possible benefits of using these weapons against bridges and similar precision targets. They did so out of a fear like that inhibiting the United States from early use of the proximity fuze overland. Hitler feared the Allies would capture a dud and be able to use the technology against Germany with greater profit than was possible for the Luftwaffe. Hitler had a case. The solution for the allies was merely the establishment of air superiority. The Luftwaffe bombers were so cumbersome with the weapons carried externally that they forfeited what little chance they had for survival in the presence of Allied fighters. By the fall of 1943, the Allies had such a great leg up on an overall air superiority that the Germans could not hope to benefit from offensive guided bombs. The would have to learn how to defend their homeland first. Hitler need not have denied himself. He continued his prohibition even into the spring of 1945. By then, both the U.S. Army Air Forces and U.S. Navy had guided weapons programs well along in development, and had used them successfully in combat. In fact, the navy programs were substantially in advance of those particular German weapons. One division of the National Defense Research Committee had been assigned to work on the weapon guidance, and the ideas underlying radio control had been well known long before World War II. The work to adapt them to usable weapons was much more in the realm of development than in that of basic research. By 1945, these ideas had evolved through the navy DRAGON, PELICAN, to the BAT program. The BAT was a glide bomb that could be directed from the airplane. It also had its own radar that could track the target and generate correction signals without any assistance for the "mother" aircraft--permitting the latter to flee the danger zone well before impact of the weapon. The BAT had actually sunk a Japanese destroyer and numerous transports from about 20 miles before war's end. The wartime work yielded a substantial data base for the peacetime development that lay ahead.

United States Wartime Guided Bombs

The United States Army Air Forces and numerous programs aimed at giving weapons direction after launch. Many of them were glide bombs, like the Luftwaffe Fritz-X, and the Army airmen were exploring and impressive number of avenues. On one of his visits to London, General Heny H. Arnold, Commanding General, Army Air Forces, had noted that viewed from above, the greater part of the surface of the city was not covered with buildings and the greater part of the bombs falling vertically would hit nothing valuable. This occurred before Pearl harbor, and glide bomb programs had been under way for some time. Some were striving for remote control by radio similar to the Fritz-X; others preset gyroscopic controls as in the German V-1, and still others were working with TV, radar, and infrared seekers. Arnold was an impatient man. Seeing that the version with a simple automatic pilot could be had soonest, he instructed the effort be concentrated there. Though that retarded those programs that had any hope of yielding precision with standoff, a usable GB-1 with a trained B-17 outfit had been deployed to Great Britain by the end of 1943. That was the darkest hour for 8th Air Force, and the new weapons were not tried in combat until its crisis had passed--in May 1944. The combination of the long time of flight arising from gliding (instead of free-fall) with gyroscopic control yielded very poor accuracy. The bombs fell into the City of Cologne all right, but the commanders of 8th Air Force were still clinging to their daylight precision bombing theory, and it seemed like area bombing to them. They therefore rejected the GB-1, and the glide bomb programs employing seekers were retarded to the point where they could not be finished in time for the war.

Arnold was not concerned with attribution when he mandated a priority for the simplest of the glide bombs for it was not the standoff launch that he desired. It was a flat trajectory to increase the odds that a bomb delivered to an urban area would find a vertical wall rather than a flat open space. The glide bomb, however, had to be carried externally and entailed serious sacrifices in range and payload that would have detracted from any advantages gained from a flat trajectory. The developers of the glide bombs with seekers, however, were concern with both precision and survivability as the sought to deliver a bomb on a point target while the bomber itself remained well outside the range of the most serious ground-based threats. Research and development programs were under way from the early years of the war (and even before 1941) the envisioned the use of light contrast, television, radar and infrared seekers. However, the technology had not advanced far enough to put any of these systems into production. Their target discrimination was still so limited that the main application would have had to be against maritime targets that stood out well against their background. The guided weapon that was deemed most promising to the Army Air Forces was the AZON which was not a glide bomb at all. It employed standard U.S. Bombs and fuzes, specifically the AN-M-65 1000-pound bomb, and a modular tail section in place of the standard fins.

The AZON tail fin unit contained a gyroscopic component that worked through horizontal control surfaces to maintain the weapon in an upright position during its fall. The rudder was moved on radio command by the bombardier watching the fall o f the bomb. The tail unit included also a bright flare the enabled him to observed it all the way to the ground from altitudes well above 10,000 feet. He had a joystick-like control box in his bomber's nose compartment that generated the transmitter signals that were picked up by the bomb's receiver and translated into left-right commands. The equipment permitted the use of five different frequency channels so that five different bombardiers in the same formation could control their weapons simultaneously--or if all the bombs were set on the same frequency, one bombardier could control all of them while watching only one. The 1000-pound versions of the AZON was designated the VB-1, but another unit was built for a standard warhead twice the size and was designed the VB-2. The smaller was the one built in the greatest numbers and most used in combat.

The RAZON was more advanced than the AZON though the principles were similar. Designated VB-3 and VB-4 in the 1000 and 2000-pound sizes, the RAZON also was guided by a bombardier watching the flare in the tail. The commands were sent to the bomb, also through a receiver in its tail, but the modifications to the sights were a bit more complex in the RAZON than in the AZON. Watching the bomb from above, it was much easier for the bombardier to perceive variations in its movement right and left than it was n range. Consequently, some modifications were made to the Norden bombsight to help measure the bomb's trajectory in its vertical dimension. That slowed development some. Still, the feeling among the developers was that they should not get overcommitted to the AZON which gave them precision in azimuth only when the RAZON that would soon be available was controllable in all directions. In the end, the RAZON was not ready until the summer of 1945 while the AZON was already in combat in Europe and the Far East.

The AZON program matures late in 1943. During the next year, it was first deployed to Europe where it was used against passes and bridges in Northern Italy. The AZON was naturally adapted best to long, narrow targets like bridges and railways. In fact, one of the test crews at Eglin suggested that the normal criteria for measuring a bomb's effectiveness be changed to yield a more realistic evaluation of AZON. The traditional method was to measure the distance that each bomb fell from the center of its target, no mater what the direction, and to average them to produce a figure called "Circular Error Probable (CEP)." That was a vital statistic for upon it depended all sorts of important decisions from the number of crews that had to be trained to the number of bombers that had to be built. But in the case where a bomb was controllable in a lateral direction only, its accuracy was really much better than the standard CEP figures would suggest. In the case of a 1,000 yard bridge, for example, a bomb that was 300 yards long or short was just as good as one that could hit the bull's eye every time. In any event, though some feats were achieved, the results reported back from Italy were mediocre.

The Air Proving Ground Command tests of the AZON revealed another curious thing. When a pattern of AZONs was dropped in one salvo and controlled to the target, the results in one way were not as good as they were in standard, uncontrolled bombs of the same size. Though a direct hit for one bomb in the AZON salvo was likely, the rest of them dispersed more than did uncontrolled bombs. The testers decided that was so because the standard bombs slowly rotated on the way to the target. The AZONs, however, were prevented from doing so because they were held erect by their gyroscopes. There were imperfections in the manufacture of all bombs casings and tail assemblies. In the case of the usual bomb, the rotation meant that it would deviate to, say, the right for a while, but then when it turned over, the error would be to the left and the would cancel each other out. Since the AZON did not turn over, all its errors were in the same direction. The bombardier's commands caused all the AZONs to move in the same direction so that only the one he was concentrating on could be controlled into the target. The rest would deviate from the bull's eye by the degree to which their aerodynamics differed from the controlled item with out any of the benefit arising from cancelling errors.

One of the approaches used at Elgin Field to overcome the dispersion problem was to string the bombs together on a cable. When such a group of bombs was released, they began to whip each other around in the same way as children skating in a chain. As the skater at the end of the chain sometimes cannot hang on, so, to the strung together bombs would get violent enough to snap the cable. Another attempt was to string them together with an elastic nylon rope--which made the gyrations all the more violent. In the end, the testers and those in the combat theaters using the bombs had to find tactical instead of technical solutions.

The tactical approach was to send a formation of bombers after the target and have each one drop just one AZON at a time and each bombardier guide his own bomb at the target independently. However, that meant that no more than five airplanes could go at the bridge at a time because there were only five radio channels available for transmitting the commands to the missiles. Of course, one could attack the target with a series of five-plane waves with the later ones avoiding interference with the earlier bombs by delaying until after the former had impacted. The trouble with this was the gunners concentrated around the bridges would have plenty of time to get ready for the subsequent waves and since each bomber could carry many AZONS, Each would have to pass over the target many times. Even though the Japanese defenses were not nearly as proficient as the German, the were good enough to make that dangerous. Later weapon systems overcame that by building in many channels into receivers and transmitters but that was difficult to do under field conditions.

By the latter part of 1944, when the AZON became operational in Burma, the U.S. Navy and Army Air Forces had just about closed Japanese maritime traffic, especially to places so distant as Southeast Asia. The Japanese, therefore, had to supply overland the armies they had in the region. In Burma's rough terrain, everything had to come over a limited number of bridges. Both the Japanese and the USAAF recognized the vulnerability of such choke points. The Japanese concentrated their anti-aircraft defenses there, and the U.S. airmen labored for a way to knock the spans down - without losing to many airplanes. The trouble was that the bridges were very hard to hit while a near miss would simply not do. Yet, if one tried to overcome the problem with numbers by making many attacks with bigger formations until a lucky hit brought down the bridge, then he would also be improving the odds for the enemy gunners. When the AZON came along, it was a substantial step in the right direction. Only 459 of them were used in Burma. Yet 27 of these bridges were dropped by AZONs. As these were 1000-pound bombs, this first step was impressive enough. (As shall be later seen, in Korea it was to require four direct hits with bombs that size (on the average) to take out a bridge.)

Another tactical approach avoided the problem of the vulnerability of bombers as they progressed along a more or less steady track while their bombardiers guided the bombs to the impact. That was to turn the bombers into aerial bomb trucks and put the bomb guided in another airplane altogether. The bombers then were flying with P-38 fighter escorts usually well above the attacking formation. Not only did the extra altitude yield the fighters more security against the anti-aircraft guns, but Japanese tactics called for concentrating their fire on the bombers and they seldom aimed at the escorting fighters. Some P-38s were therefore modified in the theater into a "droop snoots" version. They accommodated an additional person in front of the pilot; a bombardier with the identical equipment provided the AZON aimers in the bombers themselves. Immediately after "bombs away," then, the bombers would break into evasive action while the "droop snoots" continued on course guiding the AZONs their bombers had released--unmolested by the Japanese gunners below who did not immediately realize what was happening.

Postwar Decline

Notwithstanding the encouraging results in Burma, the AZON program soon died. The U.S. demobilized in late 1945 and early 1946, and the Cold War had not yet been recognized. The limited research and development funds that were available in the absence of the wartime urgency were spent on the potentially more capable RAZON. Not only was that more complex, but also all electronics depended on vacuum tubes, which limited the reliability of such weapons and made the research, development, and testing programs tedious. The development and testing continued and in 1947 a report suggested that in its state then, the RAZON was better than the standard, unguided, bombs in "some" tactical situations, but repeated the complaint on the electrical and electronic parts of the subsystem. It also reported that the work on easing the controlling of the RAZON in range was continuing. The sights had been modified, and a system was devised for using two people to control the weapon, one for range and one for azimuth, which yielded a small improvement in accuracy, but not enough to justify an additional bombardier on the crew. The problem of bomber vulnerability after bomb release and during controlling continued. Finally, when the controlling equipment did malfunction, it was liable to throw the controls hard over and cause gross errors far greater than any arising from imperfections in the ballistics of uncontrolled bombs.

By 1949, progress with RAZON was sufficient for the Air Force to deploy some of the bombs with technical personnel to an operational unit in the Far East Air Forces for further work. The personnel departed for Okinawa's 19th Bombardment Group early in 1950, before war came in Korea, There was no action there, and they were soon reassigned to other work. When the war broke out in June, it was soon discovered that the RAZON program in the 19th had languished and needed rejuvenation.

A new team was assembled to train Group personnel in the maintenance and use of the weapon. The new RAZON team (the greater part of which came from the Air Proving Ground) was discouraged upon arriving at Okinawa. Not only had most of the original personnel disappeared without having been able to train the members of the 19th Bombardment Group, but the equipment was in poor state. Some B-29s modified for RAZON had indeed been deployed to Okinawa early in 1950, but the RAZON equipment had not received any maintenance. As for all the tail assemblies, very few of them were on station being either in the warehouses of the base at Guam or enroute. Further, it turned out that bad packaging of the tail assemblies had resulted in damage from rough handling and from the corrosion suffered in humid and warm climates. The results were a delay for maintenance before a full scale combat test could begin and low reliability of the first lots of weapons.

Korean Combat Experiments

The combat test began in August and were plagued by the problems described above. Numerous duds among the bombs which had nothing to do with the controlling equipment or personnel counted as bad rounds in the test results. Some of the duds were caused by fuze malfunctions probably, but a series of them was proven to have arisen from faulty bomb shackles in the airplanes of a single squadron. They did not properly start the arming process when the bombs were released. Too, a part of the mission of the RAZON team was to train the bombardiers of the group in the use of the weapon, which resulted in numerous training drops that were not as good as they might have been had test personnel done the dropping. The team argued that the first month or so of operations should be discarded as a valid test, and it is certain that the results after 26 September were much better.

The RAZONs used by the 19th Bombardment Group in the September tests were the 1000-pound size, the standard bomb of World War II. The control units, though, were better than the AZONs in one respect. They could handle commands in two dimensions, and do it on any one of 47 discrete channels. One of the problems encountered had to do with this data link. At first, the proper check out equipment was unavailable in the theater, especially power sources of the correct voltage which resulted in defective tuning of the receivers aboard the bombs. That, in turn , allowed spurious signals to be picked up by the bombs' control mechanism so that emissions from the airplane's radar, or even its ignition systems, sometimes sent the weapons off in unwanted directions.

By the end of September, that difficulty had been overcome. In the following month, the 19th flew 9 missions of 21 sorties against North Korean Bridges - all using warheads now (1986) thought to be much too small for such stout targets. Those 21 sorties dropped 154 RAZONs (each Superfortress could carry 8 of them at a time). Unhappily, of the 154 trucked to the North, only 92 responded properly to the bombardiers' commands. Of those 92, however, 20 made direct hits on bridges and 10 of the spans were destroyed. In total, demolished 15 bridges, notwithstanding that on the average each of these successes required 4 direct hits from the 1000-pound warhead. Clearly, the weapon was far from perfect, but the potential was equally clear.

World War II had proved that buildings and bridges were sturdier than had been supposed in 1930s. The U.S. Strategic Bombing Survey had made a major point that the bombs of the USAAF had generally been too small for their objectives. Thus, even before the Survey was published in 1945, the USAAF had a program for a large guided bomb. This program was the marriage of British big-bomb technology with the guidance technology of the AZON and RAZON.

The Royal Air Force used huge bombs before the USAAF, and by war's end had built them up to 22,000 pounds. The USAAF, however, had bombers adapted to daylight attack which meant that they had to carry more defensive armament and ammunition and, in turn, that resulted in smaller bomb bays and bomb loads than those in the Halifaxes, Stirlings, and Lancasters. The most used bombs by the American air forces in the World War II ranged from the 500-pound to the 2000-pound sizes, though there was a 4000-pounder that was sometimes dropped. So, toward the end of the war, the USAAF copied the British 12,000-pound "Tallboy" which had been designed for deep penetration with a large explosive charge in its warhead. In principle, the guidance system that the USAAF designed for the "Tallboy" was identical to that in the RAZON. In fact, since the 12,000-pound bombs were so expensive and scarce, it was the practice to completely train the bombardier on the before entrusting a TARZON (as the new, large guided bomb was named) to his care. Though the USAAF had finally produced a bomber that was twice as large as the ones it had used against Hitler, and larger by a wide margin than those used by the RAF, even the B-29 could not carry the TARZON inside its bomb bay. Rather the airplane had to be modified so that it could handle the weapon with part of it projecting below the airplane's belly. To get the bomb aboard, it first had to be rolled into a special pit, and then the aircraft had to taxiied in place above it--a cumbersome procedure.

After the RAZON team had accomplished its training task, the 19th Bombardment Group was deemed self-sufficient and capable of independent operations and training for new individuals. In early 1951 the deployment of the TARZON to Okinawa began. Though the test were slow in getting under way, one bomb was dropped in January and two more in February. Both of the latter destroyed bridges in one shot. In March enough missions were flown to bring the TRAZON total up to six bridges destroyed. But then difficulties began to mount. During the winter, the pressure to drop the bridges across the Yalu had not been intense. The river was frozen and could be crossed a top the ice almost any place. As spring approached, the Communist began building several bypass bridges to back up the vital Sinuiju Bridge. The commanders decided that the main bridge should be attacked, and on 29 March, three of the Superfortresses were loaded with TARZONs. The Group Commander himself flew on one of the crews. Shortly after takeoff, one of the B-29s experienced mechanical trouble and had to be returned to the home field. The commander's airplane then had problems for unknown reasons, and had to ditch at sea. There were no survivors. The last of the three planes made it to the Yalu and released its huge weapon but missed the target.

Some TARZONs were left on Okinawa, and another was dropped unsuccessfully, and another was dropped unsuccessfully in early April. Still another was loaded up for another try on the Sinuiju Bridge on 20 April. As the B-29 was laboring upwards right after its takeoff, something went wrong and the crew had to jettison the great bomb to lighten the plane in the hopes of making it back to the field.* The TARZON hit the water with an enormous blast, but fortunately, the Superfort was far enough away that the crew lived to tell about it.

The conclusion of the subsequent investigation was that the fastening of the TARZON tail unit onto the "Tallboy" bomb casing was inadequate. When it hit the water, the tail broke off and yanked the wires out of one or both of the arming mechanisms (only one of the fuzes has to work to detonate a bomb). The program was suspended for safety because it was believed in the same defect had caused the accident in which the Group Commander had died a few weeks earlier. Added to that, some believed the program to be distracting the 19th from its primary mission. Too, a flare problem had to be overcome. By then 30 TARZONs had been dropped and 6 bridges destroyed.

By the time of the Korean War then, America had developed practical guided bombs capable of hitting small, tough targets with good precision at a far higher rate than conventional bombs--even those delivered in the dive-bombing (dangerous) mode. They still had problems, but none of the problems was very complex nor required new, scientific discoveries for solution. Rather they were engineering puzzles that were less dependent upon inspired imagination and more responsive to time and effort than were those of the pure sciences.

The difficulty with keeping the bomb in sight seemed soluble by improving the flares to make them burn brighter and longer. The trouble with the "safe salvo" feature was less daunting for it was only a matter of strengthening the connections between the bomb casing and the tail units. The limitations on the number of bombs that could be controlled at the same time had already been eliminated through the installation of 47 channels in the RAZON receivers to take the place of the 5 that had been in the AZON. It is quite true that none of the attempted solution to the problem of having remain on a predictable flight path for a minute or so during the fall of the bomb were really satisfactory. The degree to which this increased vulnerability was certain to be much less than the degree to which it was reduced by the lower number of penetrations of dangerous target areas that would be required to take out any given bridge or similar target. Though the technology was available, development programs were necessary to perfect both the RAZON and TARZON, or to build new precision-guided bombs based on the apparent lessons of the Korean experience. that such development programs would follow was by no means inevitable.

Research and Development Organisation

Even before the Korean War, there had been some feeling in the Air Force that nonnuclear bomb the Air Force that nonnuclear development, and nonnuclear aircraft armament in general, were orphans. The service was moving toward "concurrent" development or a "system approach" to air research and development work. That is, the aircraft, its subsystems, and supporting systems were to be treated as a whole. Development of all the parts had to be brought along "concurrently" or in a synchronized way. Some authorities about the time of the Korean War thought that the USAF had learned to do that very well in terms of airframes, engines, avionics, ground support equipment and many other items--except for armament. A variety of reasons were cited. The traditional approach to weapons research and development was an evolution one, dependent upon incremental improvements to weapons based on matured technology. But the practically simultaneous arrival of nuclear weapons, ballistic missiles and jets seemed so revolutionary as to undermine the tradition. Quantum jumps seemed possible. So much energy was concentrated on such things that there was little left over for what seemed like unimaginative improvements in the guidance for the same free-fall bombs the USAF had been using for many years.

Another factor inhibiting nonnuclear armament development programs well into the 1950s and beyond was the lack of a single advocate for such research. The responsibility had been split several ways in years past and remained so even after the coming of an independent Air Force. Throughout the interwar period, World War II and well past the Korean War, the U.S. Army Ordnance Department was responsible for the development of all high explosive, fragmentation, and semi-armor piercing bombs for the Air Force. In practice, those things that left the aircraft belonged to Ordnance; those things that stayed with the plane were the province of the USAAF and later the USAF. Consequently, there was some tendency for bombsight and bomb rack development to have a well-established group of advocates inside Materiel Division (and later Air Materiel Command (AMC) and still later Air Research and Development Command (ARDC)). But since the bomb development belonged to the Army, it had few advocates within the Air Force. Incendiary bombs were the responsibility of the Army's Chemical Service headquartered at the Edgewater Arsenal in Maryland and a similar situation prevailed. The development of armor-piercing bombs was the responsibility of the Bureau of Ordnance of the United States Navy with similar effects for the Air Force. It followed that new jet engines, swept-back wing jets, and bomb aiming radar would have priority in Air Force budgets over programs aimed to build upon the RAZON-TARZON experience.

For a time in the early 1950s, it seemed that an advocacy for nonnuclear aircraft weapon development might be building at Eglin. There had been a good deal of discussion in connection with the "Unification" Act of 1947 that in might result in disunification and duplication instead of greater efficiency. Thus, there were rather strong inhibitions against the establishment of laboratories and shops that might be deemed duplications of the arsenals and laboratories of the Army and the Navy. But the air leaders in the aftermath of the Unification Act deemed the need imperative to coordinate research and development of air armament with that of other parts of air weapon systems. In early 1949 they moved to establish an agency at Eglin to do that. This resulted in the foundation of the Air Materials Armament Test Center on 15 December of 1949 as a part of the Air Materiel Command. The Air Proving Ground Command continued at the same location outside the jurisdiction of AMC. A part of the function of the Air Materiel Armament Test Center was:

to collect and to concentrate at one location the widely scattered activities engaged in air armament development in the interest of greater efficiency and expeditious development of Air Force armament equipment

The Proving Ground had been involved in armament testing ever since its beginning in the 1930s and in the formal sense, its function had always been operational suitability testing and not experimental work. In a less formal way, though, many suggestions did arise from its proof testing that had important effects on subsequent development. Soon after the founding of the Air Materiel Armament Test Center, the research and development responsibility was separated from the Air Materiel command and made the mission of a new major command, the Air Research and Development Command (ARDC) (later to become Air Force Systems Command(AFSC)). The new armament testing organization was transferred to the research and development organization as (ultimately) the Air Force Armament Center (AFAC). In the days of the Korean War, then, it seemed that the nucleus of an organization that would push for improved guided bombs (with an assist from the Weapons Guidance laboratory at Wright-Patterson AFB) had been establishment and that development would continue. However, this promising start was overtaken by events and did not mature.

Changing Research and Development Priorities

A combination of events on different levels arrested the development of guided bombs during the latter 1950s. When peace finally came in Korea, America recoiled against limited (nonnuclear) wars of any kind. The truce was followed by the era of Massive Retaliation. There would be no more Koreas. Instead, if such provocations occurred again, the United States might respond with full-scale nuclear attack against the real source of aggression--presumably Moscow. The need, then, would not be for improved TARZONs that could break down bridges in limited wars. It would be for long range systems of immense sophistication that would be the essence of strategic warfare. Moreover, the new Administration had come to office on a campaign that promised to balance the budget. The movement to marry ballistic missile and nuclear technologies to form Intercontinental Ballistic Missiles (ICBM) was growing. Though the Air Force was getting close to half of the services' budget, the Strategic Air Command (SAC) was consuming a disproportionate share of that under the hand of General Curtis LeMay trying to rebuild it from the "Hollow Threat" it had become in the late 1940s. The scientist and engineers were proceeding to reduce the size and cost of special weapons. Money allotted for the tactical air forces was going to create tactical nuclear weapons for them, along with all the supporting structure that entailed. Most of the research and development money that was available to the Air Force, then, was going to those agencies engaged in work on nuclear weapons of all kinds and on emergent strategic missile technology. Elgin had had the pioneer missile unit in the Air Force, but the unit that descended from it had been transferred to Patrick Air Force Base in the mid 1950s.

Guidance for the old-style bombs was important, but even those microscopic funds that were available for such weapons had other pressing demands places on them. The warheads that had been used on the AZON and RAZON were the standard bombs designed in the first instance for internal carriage in the bomb bays of airplanes like the B-25 and B-17. The parameter that drive the design of the shape of the bomb case was the need to load as many bombs as possible into a given bomb bay. If the aerodynamics were sufficient to yield a consistent trajectory, whatever the drag, that was enough. Those bombs, then, were stubby affairs so that many of them could be arrayed inside the bays. After they had been designed and immerse plants were set up for their production, the World War II fighter-bomber was developed. External carriage of substantial bombs became far more common than had been anticipated. Aircraft speeds had risen during the War, and with the coming of the jets afterwards, there was an even greater leap. As the drag of any shape increases with the square of the air speed, the use of the stubby bombs on external pylons threw away one of the chief advantages of the jet - its speed. The reduction of the drag coefficients of the sizes of bombs carried by fighters would therefore yield disproportionate dividends in range and speed. That, then, was an item that had a high priority for any development funds and in the 1950s both the Army and Navy developed a new series of low drag bombs that are still in use in 1986.

When in 1957 the Soviets placed a satellite into space ahead of the United States, the trends were accentuated. The emphasis through the late 1950s at Elgin was very much on testing systems related in one way or another to strategic air warfare, or that least tactical nuclear warfare. The Eglin Gulf Test Range was built up in that time for the testing of such strategic offensive missiles as the Hound Dog and strategic defensive weapons like the Bomarc. Surface launched tactical missiles were tested as well, but they usually had a nuclear options as with the Matador and the Mace. The Air Force still did not have the responsibility for research and development on bombs, and about all that happened in the realm of nonnuclear free-fall weapons was the issuance of the low-drag Mark 80 series designed by the Navy and the M-117 and M-118 with improved shapes developed by the Army's Ordnance Department. Very little was done in either the Army or the Air Force to increase the guidance technology base for air-to surface weapons.

By the spring of 1960, the development of nonnuclear guided bomb had been languishing for some time. An event occurred that should have stimulated rapid change in the slow pace of United States nonnuclear guided bomb development. Francis Gary Powers was brought from the Soviet skies where he and his colleagues had flown unmolested in the U-2s for some years. The heights at which he was brought down--by a surface-to-air missile (SAM)--were thought to be far above the reach of the Soviet ground defenses and interceptors. the implications were soon discerned in many areas of military aviation: high-altitude supersonic planes like the B-70 would not be enough; low-level penetrators would have to be used. But in the realm of nonnuclear bombs, rapid change was still not pressed. The Army was to remain in charge of nonnuclear bomb research and development for yet another year and what research was being done on guidance for such weapons was largely in the hands of the Navy. In some ways, the problem was both easier and more important for the Navy.

*All bombs then and now were required to have a safe salvo option, that is, the crew encountering trouble over friendly territory had have the ability to lighten their airplane without fear of a bomb exploding on their own field or home territory. This is achieved normally through fastening a wire to the bomb release mechanism on the airplane. It runs from there to both the tail and nose of the bomb. Typically, there are two fuzes, one at each end. The wire is threaded through a hole in each of these fuzes and a clip is fastened to the far end to guarantee that it will not slip out. Yet it can be pulled through with a moderate force. When it is so removed, it is usually arranged to free a wind vane. After a given number of rotations, the vane unlocks the firing mechanism (a procedure called "arming"). The idea is that if the crew wants the bomb to explode, they select an option that keeps the wire with the airplane and as the weight of the bomb pulls it out of the bomb bay, it pulls the arming wires out of their holes too. Then the firing pin or other mechanism is unlocked to be actuated by impact or other force at the desired time. If the idea is that the bomb is to land without exploding, then the wire is released from the bomb rack and travels down with the bomb. When the weapon impacts, the arming mechanism has not been activated and the firing mechanism is physically prevented from impacting on the primer and initiating the detonation chain.

Seeking Guidance
http://www.airspacemag.com/asm/mag/supp/am99/Paveway.html

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