<p>General-purpose (<hi format=bold>GP</hi>) bombs are the most commonly used weapons of aerial warfare. They are inexpensive, easy to produce, and have numerous applications, including providing the warhead for many precision-guided munitions (<hi format=bold>PGM</hi>s). All bombs weighing less than 2,000 lb have suspension lugs spaced 14 in (35 cm) apart; those weighing more use 30-in (76-cm) spacing. Odgen ALC manages all USAF conventional bombs, which are built at plants located in McAlester, Oklahoma and Crain, Indiana.
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<p>The <hi format=bold>Mk 80 series</hi> bombs, with an explosive content of roughly 50 per cent, are based on studies done by Douglas Aircraft in 1946. Production began during the Korean conflict, although they did not actually see service until Vietnam. The 250-lb <hi format=bold>Mk 81</hi> was found to be ineffective during Vietnam and its use was discontinued. Use of the 1000-lb <hi format=bold>Mk 83</hi> was discontinued by the USAF after limited use during Vietnam, although it will apparently be used again for JDAM weapons for the F-22. The Tritonal-filled 500-lb <hi format=bold>Mk 82</hi> and 2,000-lb <hi format=bold>Mk 84</hi> bombs are the mainstays of USAF weaponry and have been widely exported. Live USAF warheads and fins are painted FSN 34087 olive drab with a single 3-in (7.6-cm) FSN 33538 yellow band around the nose. Inert warheads have a non-explosive filler and either substitute a FSN 35109 blue band for the yellow, or are painted overall blue.
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<p>The visually distinguishing characteristic of naval GP bombs is their very rough thermal protective (<hi format=bold>TP</hi>) coating. This was developed after several tragic shipboard fires during the Vietnam War, to make bombs burn in a fire instead of exploding. During the early 1990s, when the Navy switched its filler from H-6 to PBXN-109, its Mk 80-series casings received new designations:<hi format=bold> BLU-110</hi> for the Mk 83, <hi format=bold>BLU-111</hi> for the Mk 82, and <hi format=bold>BLU-112</hi> for the Mk 84. The Air Force only uses non-thermally protected (<hi format=bold>NTP</hi>) bombs.
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<p>The most common fin fitted to GP bombs is the low-drag, general-purpose (<hi format=bold>LDGP</hi>) fin, also referred to interchangeably as the conical fin assembly (<hi format=bold>CFA</hi>). Initial CFAs did not have independent designations, and were simply referred to using the bomb designation (e.g., Mk 82 conical fin). Bombs fitted with this kind of fin are commonly called 'slicks'.
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<p>There are also a number of fins that can be configured so as to either deploy or not deploy their retarding fins. If not deployed, they have ballistics virtually identical to CFA bombs. Because of this, both the CFA and non-retarding retard finned bombs are referred to as low-drag (<hi format=bold>LD</hi>) bombs, while bombs using their retarding devices are referred to as high-drag (<hi format=bold>HD</hi>) bombs. High-drag bombs loaded in weapon bays of B-52s and B-1Bs have a <hi format=bold>MAU-111</hi> strap that unwraps from around the bomb body as it falls, delaying fin opening until the weapon is well clear of the aircraft.
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<hi style=hdr1>Mk 82</hi>
<p>All 500-lb class Mk 82 warheads have an exposed length of 71 in (180 cm) (not including fuze or nose plug) and are 13.9 in (35 cm) in diameter. The Mk 82 Mod 0 was an NTP warhead constructed from welded pipe. It featured an electrical fuze charging well and a single hoisting/suspension lug located between two 14-in (35-cm) suspension lugs. The main changes to the <hi format=bold>Mk 82 Mod 1</hi> warhead, introduced on 4 January 1955, were the switch to seamless tubing construction and the elimination of the single hoisting/suspension lug. The Navy's Mk 82 Mod 2 was probably introduced in 1973 and is thermally protected. Neither the NTP Mk 82 Mod 3 nor the TP Mk 82 Mod 4 were produced. These warheads featured internal scoring to increase fragmentation effects. Mk 82s cost about $500.
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<p>The Air Force uses the inert <hi format=bold>BDU-50</hi> to simulate the Mk 82. These practice bombs have no internal plumbing for fuzes. There are two versions: the BDU-50/B can only be configured with tail fins, while the BDU-50A/B can also be fitted with LGB guidance kits.
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<p>There are three operational Mk 82 conical fin designs, only two of which are used by the Air Force. The 22-pound <hi format=underline>Mk 82 Mod 1</hi> has a 1.5 degree fin cant to spin-stabilize the bomb and several doors and panels to allow access to tail fuzes. This fin is 26 in (66 cm) long and has 15-in (38-cm) span fins. Like the Mk 82 CFA, the 27-lb <hi format=underline>MAU-93/B</hi> attaches to the bomb with six set screws. However, it is 43 in (109 cm) long and has a 19.6-in (50-cm) fin span. The Navy's BSU-33 was developed during the late 1980s. The same length as the Mk 82 CFA, this FSN 35376 gray fin adds 2.5 degree metal wedges to the left rear corner of each fin to increase spin rate.
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<p>The 60-lb Mk 15 Mod 0 Snakeye retarding fin was adopted for use in April 1964. The Mk 15 Mod 1 was introduced in April 1967, and the Mk 15 Mod 2 in December 1967. The <hi format=underline>Mk 15 Mod 3</hi> was introduced in April 1970, and was the first version used by the USAF. The other version used by the Air Force was the <hi format=underline>Mk 15 Mod 4</hi>, which was introduced in November 1971. The Navy's 66-lb Mk 15 Mod 5 retained the release band and latching lever which had previously separated from the bomb to prevent damage to composite aircraft structures. The Mk 15 Mod 6 refined this design. In late 1987, the Navy introduced the BSU-86 to replace the Mk 15. These fins are painted FSN 36375 gray.
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<p>The main disadvantage to weapons fitted with Snakeye fins was that they forced many aircraft to slow down to deliver them. The Goodyear Aerospace air-inflatable retard (<hi format=bold>AIR</hi>) fins allow Mk 80 series warheads to be released at much higher airspeeds than were possible with Snakeyes. The <hi format=bold>Mk 82 AIR</hi> is often referred by its $600, 55-lb fin's designation: <hi format=underline>BSU-49</hi>. The Navy's <hi format=underline>Mk 16</hi> uses the BSU-49 shell with a parachute replacing the ballute and is used with mines.
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<hi style=hdr1>Mk 84</hi>
<p>All 2,000-lb class Mk 84 warheads have an exposed length of 96 in (244 cm) (not including fuze or nose plug) and are 18 in (46 cm) in diameter. The Mk 84 Mod 0 was an NTP warhead with an electrical fuze charging well and a single hoisting/suspension lug located between two 14-in (35-cm) suspension lugs. The first operational bomb, the Mk 84 Mod 1, was introduced in February 1955 and featured 30-in (76-cm) suspension lugs, and was used extensively in Vietnam. The slightly modified Mk 84 Mod 2 was introduced in March 1972. The Navy's Mk 84 Mod 3 was introduced in May 1973 and was the first TP Mk 84. The NTP <hi format=bold>Mk 84 Mod 4</hi> is the current version used by the Air Force. It was introduced in August 1974 and eliminated the single hoisting/suspension lug. The Navy's Mk 84 Mod 5 was a TP version of the Mod 4 and was introduced in May 1979. The NTP Mk 84 Mod 6 and TP Mk 84 Mod 7 were introduced in April 1989 and had their fuze arming wells relocated for compatibility with F/A-18 bomb racks.<hi format=bold> Inert Mk 84</hi>s have no unique designation and are simply normal casings with non-explosive filler. Mk 84s cost about $1,900.
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<p>The original Mk 84 Mod 0 conical fin had a 25.3-in (64-cm) fin span, was 53 in (135 cm) long and could be distinguished by its rounded cap behind the fins that did not allow access to tail fuzing. The 114-lb production fin, the <hi format=underline>Mk 84 Mod 1</hi>, has several doors and panels to allow access to tail fuzes, a 2 degree fin cant to spin-stabilize the bomb, and deletion of the rounded tail cap that shortens its length to 49 in (124 cm).
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<p>The USAF's <hi format=bold>Mk 84 AIR</hi> uses the 97-lb <hi format=underline>BSU-50</hi> fin. Designed primarily for the F-111, its release speed is so high that the Navy did not acquire it. During Desert Storm, the Navy decided it had a requirement for a retarded Mk 84 and authorized the 87-lb <hi format=underline>Mk 11</hi> parachute fin for overland use, a function it already filled for underwater mining operations.
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<hi style=hdr1>M117</hi>
<p>While the Vietnam-era Mk 80-series bombs had Navy designations, the Korean-vintage 750-lb M117 has a US Army Air Force designation. Originally classed as a demolition bomb because its explosive content was about 65 per cent, it was widely used in Vietnam. Subsequently, the $500 M117 has only been used by the B-52. Developed as the T54, the original Minol-filled version was designated M117. The M117A1 deleted the single suspension lug, and was followed by the Minol II-filled M117A2. The M117A3 was filled with Tritonal. The M117A1E1 was an A2 that could be filled with either Tritonal or Minol II. The M117A1E2 was an A1 filled with Minol II, and the final version was the <hi format=bold>M117A1E3</hi>, a modified A1E1 filled with Tritonal. M117s were exported, especially to Israel, which used them frequently with F-4s during the Yom Kippur War of October 1973.
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<p>Originally, low-drag M117s were fitted with 52-lb <hi format=underline>M131</hi> conical fins that were 49 in (124 cm) long with a 23-in (58-cm) fin span. In the early 1970s, the 64-lb <hi format=underline>MAU-103/B</hi> conical fin was introduced, featuring strakes, a 50-in (127-cm) length, and a 19-in (48-cm) fin span. A modified version of this fin, the <hi format=underline>MAU-103A/B</hi> increased fin-span to 22 in (56 cm). The high-drag bomb, commonly known as the <hi format=bold>M117R</hi>, used the 117-lb <hi format=underline>MAU-91A/B</hi> and <hi format=underline>MAU-91B/B</hi> 'Snakeye'-type fins through the 1991 Gulf War. These 22-in (56-cm) span fins are 48 in (122 cm) long and have minor differences in their fin latching mechanisms. The <hi format=bold>M117 AIR</hi> was adopted after the Gulf War and uses the 95-lb <hi format=underline>BSU-93/B</hi> ballute fin, with a 20-in (50-cm) fin span and a 40-in (101-cm) length.
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<p>The <hi format=bold>MC-1</hi> is a M117 case filled with 24 US gal (90 liters) of the lethal nerve gas Sarin (<hi format=bold>GB</hi>). It is fitted with bursters to rupture it on impact, dispersing its contents. Unlike normal bombs, this chemical bomb is painted medium gray, with a green nose band.
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<hi style=hdr1>BLU-107</hi>
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<p>The USAF adopted the 450-lb French Durandal for use by F-111s as the <hi format=bold>BLU-107</hi> runway denial weapon. Its delivery requires a non-maneuvering, level flight path at low altitude across the target—a highly defended runway. The $43,000 penetrator consists of a warhead, rocket motor and parachute. Designed for carriage on <hi format=bold>BRU-3</hi> bomb racks, an aerodynamic fairing is installed over the nose of BLU-107s carried on the front stations, while the blunt, penetrator nose is exposed on the aft weapons. When released, a braking chute extracts the main parachute and then drops away. The main chute slows the weapon and points it at the ground. When the proper downward angle is achieved, the main chute is released and the rocket motor fires the warhead through up to 16 in (40 cm) of unreinforced concrete. After it penetrates beneath the runway, a delay fuze detonates the 33-lb warhead, heaving the runway surface upward, thus making it unusable.
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<p>French Jaguar As actually dropped Durandels on the first day of the Gulf War. F-111Fs attacked the vast Iraqi airfields repeatedly, using LGBs almost exclusively. They had great success in making the runways and taxiways unusable by detonating 2,000-lb LGBs at their intersections from an altitude safe from ground fire.
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<hi style=hdr1>BLU-109</hi>
<p>The success of the Israeli air force in destroying the Arab air forces on the ground during the opening minutes of the 1967 Six Day War prompted the major tactical air forces on both sides of the Iron Curtain to spend billions of dollars on hardened aircraft shelters (<hi format=bold>HAS</hi>s). These shelters were impervious to most GP bombs. Naturally, the need arose for a bomb capable of penetrating HASs and other hardened facilities. The answer to this requirement is built by Lockheed Missiles and Space Co. and is commonly referred to as the improved 2,000-lb bomb, or I-2000, although its actual designation is <hi format=bold>BLU-109</hi>. To prevent it from breaking up before it penetrates the hardened exterior of its target, the BLU-109 has an explosive content of only 25 per cent. The rear of the bomb is flared slightly so as to be compatible with any Mk 84 fin group. Since all of its targets require precise aiming, BLU-109s are only used as part of a PGM, although some were tested with conical fins when carried by F-16 test aircraft. Versions include the Air Force's BLU-109/B and the Navy's thermal protected BLU-109A/B. Including an FMU-143 fuze, each BLU-109 costs about $12,500.
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<hi style=hdr1>BLU-113</hi>
<p>The ultimate penetration warhead, the Lockheed <hi format=bold>BLU-113/B</hi>, was developed, produced, deployed and used in combat in only 17 days. Used for the 4,700-lb GBU-28/B 'Deep Throat' bombs, they were machined from spare 8-in howitzer barrels to resemble very long BLU-109s, but with an explosive content of only 15 per cent. Published reports indicate the bomb was dropped from relatively high altitude, maximizing both its kinetic energy (five times that of the GBU-24/27) and impact angle, enabling it to penetrate over 100 ft (30 m) of earth or 20 ft (6 m) of concrete to destroy command bunkers thought safe from all but nuclear attack.
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<hi style=hdr1>General-Purpose Bomb Fuzes</hi>
<p>Often overlooked, the different fuzes used with GP bombs are absolutely crucial to inflicting the desired damage to a given target. The most easily identified of all nose fuzes was the M1A1, commonly known by the term 'daisy cutter'. Developed during Vietnam as a kind of poor man's proximity fuze, it was nothing more than a length of explosive-filled pipe with an M904 fuze on the end (usually 36 in long, but also available in 18- and 24-in lengths). This allowed the bomb to explode before it buried itself in the soft soil of Vietnam, thus increasing its blast effect.
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<p>Mechanical fuzes are identifiable visually by their distinctive vanes or the M905's ATU-35 anemometer. Most electrical fuzes are cylindrical devices hidden by either a nose plug or the fin assembly. The FMU-113 proximity fuze is easily identifiable by its black, hemispherical radome.
<row><c>M904E2/3<c>nose<c>mech.<c>inst. or short delay<c>Mk 82, 84, M117
<row><c>M905/ATU-35<c>tail<c>mech.<c>inst. or short delay<c>Mk 82, 84, M117 (LD only)
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<hi style=hdr1>Blast Bomb</hi>
<p>Used in Vietnam to clear helicopter landing zones and in Iraq to detonate minefields, the 15,000-lb class <hi format=bold>BLU-82</hi> blast bomb was the largest bomb in the Air Force arsenal by 1990. During the 1991 Gulf War it was delivered only by MC-130Es, shoved out the cargo door strapped to a cargo pallet. The bomb's descent was slowed and stabilized by parachutes, and was detonated by a 4-ft long 'daisy cutter', to ensure an above-ground explosion and maximize blast and fragmentation effects. The explosive content of the BLU-82 was about 80 per cent.
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<hi style=hdr1>Nuclear Bombs</hi>
<p>All modern US nuclear bombs are thermonuclear (i.e. hydrogen bombs). Delivery options are dependent on the bomb/aircraft combination and the type of target destruction required. All have incorporated parachutes as a standard feature to assist in level weapon delivery and aircraft escape. While there may be several variants to a given weapon, only the basic designations are presented here. The weapons are sometimes referred to by the term 'Mk' instead of 'B'. In line with a change in US policy announced in September 1991, all tactical nuclear weapons were removed from USN ships and stood down from alert at USAF bomber bases. No one is happier about that than the crews who were charged with their care and delivery. By the mid-1990s, while B61 and B83 weapons remain in the inventory, the capability to quickly mount a massive nuclear strike with manned aircraft that existed prior to 1990 had virtually evaporated.
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<p>Design work on the <hi format=bold>B28</hi> family of nuclear weapons began in 1954, and they remained in service until about 1990. A modular design, it was produced as five different types of bombs and was also used as a warhead on the MGM-13 'Mace' and AGM-28 'Hound Dog' missiles. Five yields were available, ranging from 70 kT to 1.45 mT, with the tactical versions having the lower values. Yield of these weapons could not be adjusted in the field. The <hi format=bold>B28EX</hi> (for 'external' carriage) had a streamlined shape and four tail fins, but was not equipped with a retarding parachute; it had ground and airburst options. Several training versions existed, including the <hi format=bold>BDU-10</hi> and <hi format=bold>Mk 104</hi> ballistic shapes as well as the <hi format=bold>MD-6</hi> and <hi format=bold>BDU-26</hi> load trainers. The <hi format=bold>B28RE</hi> (for 'retarded, external' carriage) also had a streamlined shape, but it only had three fins, which were mounted well forward of the tail. It also had ground and airburst options, but could be delivered from low altitude. Its ballistic shape was the <hi format=bold>BDU-4</hi>.
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<p>The <hi format=bold>B43</hi> program began in 1955, with the weapons remaining in service until about 1990. A total of five yields were available, with the largest about one megaton; the yields could not be adjusted in the field. There were two versions designed for external carriage. <hi format=bold>B43-0</hi> could only be used for parachute-retarded laydown deliveries. It had a steel nose spike covered by an aerodynamic nosecone. After the bomb separated from the aircraft, the nosecone was jettisoned and the spike enabled the bomb to penetrate hard targets and be held in place for several seconds (to allow the aircraft to escape) before detonating. The <hi format=bold>B43-1</hi> was a multi-purpose weapon with a longer nose, which contained a fuzing radar. It could be used with freefall airburst, retarded airburst (with or without a ground burst backup), or retarded laydown. Several training versions existed, including the <hi format=bold>BDU-18</hi> (freefall) and <hi format=bold>BDU-8</hi> (retarded) ballistic shapes, as well as the <hi format=bold>BDU-6</hi>/<hi format=bold>24</hi>/<hi format=bold>35</hi> load trainers. B43s were carried externally by the A-4, A-6, A-7, B-58, FB-111, F-100, F-104, F-105 and F-111. They were painted gloss white with chocolate brown radomes.
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<p>The <hi format=bold>B53</hi> was based on the warhead used by the Titan II missile. It was recalled into the inventory for use by B-52s pending arrival of the B83 weapon. It was targeted against deeply buried Soviet command centers and submarine pens. While it had freefall and parachute-retarded airburst options, it would normally use a laydown (delayed surface burst) or immediate contact (surface) burst. The <hi format=bold>BDU-13</hi> was its ballistic shape, while the <hi format=bold>BDU-9</hi> was its load trainer.
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<p>The <hi format=bold>B57</hi> was designed as a nuclear depth charge, but was later adopted for use as a low-yield tactical nuclear weapon. Nicknamed the 'Dr Pepper' bomb (after the American soft drink), its delivery options included laydown, and toss (sometimes called loft) with either air or surface burst. Several training versions existed, including the <hi format=bold>BDU-12</hi> and <hi format=bold>BDU-20</hi> ballistic shapes, as well as the <hi format=bold>BDU-11</hi> and <hi format=bold>BDU-19</hi> load trainers. B57s were carried externally by the A-4, A-6, A-7, FB-111, F-104, F-105, F-111, F-4, F-16 and F/A-18. B57s were painted in the same manner as B43s.
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<p>The <hi format=bold>B61</hi>, in addition to its strategic use, was the most commonly used weapon by tactical fighters. Nicknamed the 'Silver Bullet,' because of its shape and color, it gave a whole new meaning to the claim by an American beer that, 'Silver Bullets won't slow you down!' Delivery options included freefall or retarded airburst, laydown, and toss (with either air or surface burst). Several training versions existed, including the <hi format=bold>BDU-38</hi> ballistic shape, as well as the <hi format=bold>BDU-36</hi> and <hi format=bold>BDU-39</hi> load trainers. B61s were carried externally by the A-4, A-6, A-7, FB-111, F-104, F-105, F-111, F-4, F-16 and F/A-18.
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<p>The <hi format=bold>B83</hi> is designed for attacking hardened strategic targets such as command bunkers, and nuclear weapon storage sites. It has freefall and retarded airburst, as well as surface burst and laydown delivery options. Although tested on F-111s, it was probably only operational with B-2As and B-52Hs (and B-1Bs until they were dedicated to conventional missions in the mid-1990s).
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<p>The <hi format=bold>B90</hi> was designed to replace the B57 and B61 for use by Navy A-6E, A-7E, F/A-18, S-3A/B and P-3C. It weighed about 760 lb, was 117 in (297 cm) long and 13 in (33 cm) in diameter. Flight testing began in mid-1989, with initial drop testing beginning in early 1990. The program was canceled following the change in US nuclear policy in September 1991.
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<hi style=hdr1>Nuclear Weapons Used By US Aircraft</hi>
