The B-41 (also known as Mk-41 ) was a thermonuclear weapon deployed by the United States Strategic Air Command in the early 1960s. It was the most powerful nuclear bomb ever developed by the United States, with a maximum yield of 25 megatons of TNT (100 petajoules ). A top secret document (DCI Briefing to the JCS, 30 July 1963), states “The US has stockpiled bombs of 9 MT and 23 MT...” which would likely be referring to the B-41's actual yield(s). The B-41 was the only three-stage thermonuclear weapon fielded by the U.S.
31-634: W41 may refer to: W41 (nuclear warhead) Crisfield Municipal Airport , in Somerset County, Maryland Great icosahedron Kita-Kembuchi Station , in Hokkaido, Japan Nissan Civilian (W41) , a minibus Noongar language W41, a version of the Oldsmobile Quad 4 engine Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
62-510: A laydown fuzing capability as the design of the physics package did not make that possible without extensive redesign and further nuclear testing. The B-41 was the only three-stage thermonuclear weapon fielded by the US. Two versions were deployed: The Mk-41Y1, a 25 megatonnes of TNT (100 PJ) yield, dirty version with a tertiary stage encased with U-238 ( natural uranium ); and the Mk-41Y2,
93-541: A plane crash . The John shot on July 19, 1957, was the only test of the Air Force's AIR-2A Genie rocket with a nuclear warhead. It was fired from an F-89J Scorpion fighter over Yucca Flats at the Nevada National Security Site . On the ground, the Air Force carried out a public relations event by having five Air Force officers and a motion picture photographer stand under ground zero of
124-564: A 10 megatonnes of TNT (42 PJ) yield, clean version with a lead-encased tertiary. It was the highest-yield nuclear weapon ever fielded by the United States, and had the highest publicly known yield-to-weight ratio of any weapon. During its operational lifetime, the B-41 was the most efficient known thermonuclear weapon in terms of yield to actual weight, with a 5.2 megatons of TNT per tonne (22 petajoules per tonne) ratio (based on
155-558: A 25 Mt (100 PJ) yield). Its blast yield was 25% to 50% that of the AN602 Tsar Bomba , which delivered a blast of 50 or 100 Mt (210 or 420 PJ), depending on its own configuration as a clean or dirty bomb. However even at the Tsar Bomb's theoretical maximum yield of 100 Mt (420 PJ), it would still only achieve a yield to weight ratio of ~ 3.7 megatons of TNT per tonne (15 petajoules per tonne), thus
186-453: A 900-kilogram (2,000 lb) iron lid was welded over the borehole to contain the nuclear blast, despite Brownlee predicting that it would not work. When Pascal-B was detonated, the blast went straight up the test shaft, launching the cap into the atmosphere. The plate was never found. Scientists believe compression heating caused the cap to vaporize as it sped through the atmosphere. A high-speed camera, which took one frame per millisecond ,
217-568: A weapon, and projects concerning earth motion, blast loading and neutron output were carried out. Nuclear weapons safety experiments were conducted to study the possibility of a nuclear weapon detonation during an accident. On July 26, 1957, a safety experiment, Pascal-A , was detonated in an unstemmed hole at the Nevada Test Site, becoming the first underground shaft nuclear test. The knowledge gained provided data to prevent nuclear yields in case of accidental detonations—for example, in
248-544: The Priscilla shot from Operation Plumbbob in 1957. As a consequence publications including official government documents have the photo mislabeled. The shots can be told apart by the trails of test rockets, which are prominently featured in images and footage of Grable , but appear almost completely absent at the actual Priscilla shot. In 1956, Robert Brownlee, from Los Alamos National Laboratory in New Mexico ,
279-565: The US Department of Defense requested a feasibility study for a Class B (over 10,000 lb or 4,500 kg weight) bomb and warhead. By summer of 1956, US Air Force Strategic Air Command produced a requirement for a 62-inch (1,600 mm) Class B bomb, while the DoD produced a requirement for a 60-inch (1,500 mm) Class B warhead. The University of California's Radiation Laboratory (now Lawrence Livermore National Laboratory ) proposed
310-480: The thermal radiation . As shown and reported in the PBS documentary Dark Circle , the pigs survived, but with third-degree burns to 80% of their bodies. Other pigs were placed in pens behind large sheets of glass at measured distances from the hypocenter to test the effects of flying debris on living targets. Studies were conducted of radioactive contamination and fallout from a simulated accidental detonation of
341-631: The B-41 has the highest yield to weight ratio of any weapon ever created. In November 1956, development of the W41 , a warhead version of the B41, began at Lawrence Livermore National Laboratory . Investigated as a possible warhead for the SM-64 Navaho , a cruise missile then in development, work on the warhead continued through July 1957, when the project was canceled. Operation Plumbbob Download coordinates as: Operation Plumbbob
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#1732793599253372-484: The average foot-soldier would stand up, physically and psychologically, to the rigors of the tactical nuclear battlefield . Almost 1,200 pigs were subjected to bio-medical experiments and blast-effects studies during Operation Plumbbob. On shot Priscilla (37 kt), 719 pigs were used in various experiments on Frenchman Flat . Some pigs were placed in elevated cages and provided with suits made of different materials, to test which materials provided best protection from
403-624: The blast, which took place at between 18,500 and 20,000 feet (5,600 and 6,100 m) altitude, with the idea of demonstrating the possibility of the use of the weapon over civilian populations without ill effects. The five officers were Colonel Sidney C. Bruce, later professor of Electrical Engineering at Colorado University, died in 2005; Lieutenant Colonel Frank P. Ball, died in 2003; Major John W. Hughes II, died in 1990; Major Norman B. Bodinger, died in 1997; Major Donald A. Luttrell, died in 2014. The videographer, Akira "George" Yoshitake, died in 2013. The Rainier shot, conducted September 19, 1957,
434-412: The contact fuze were made by firing 75-millimetre (3.0 in) shells through the nose of the bomb. These tests showed that there was sufficient time between contact and the firing signal being sent for the fuze design to work correctly. In August 1957, the primary of the device in a device mockup was tested during shot Smoky of Operation Plumbbob , yielding 44 kilotonnes of TNT (180 TJ). The device
465-588: The ground before takeoff. In August 1958, the first production date for the weapon slipped to May 1960. Issues with the weapon now meant that compatibility was limited to the B-47 and B-52 bombers. Compatibility with the B-70 would require significant changes to the aircraft. Further, due to the new emphasis on low level releases to avoid radar detection and due to the fact that the TX-41 could only be dropped from high altitude,
496-560: The previous decision to only use parachute retarded fuzing was reversed and it was asked to reinstate the fuzing selector. Pilot production of the weapon was authorised in April 1959 and full production authorised in September 1959. Early production of the Mark 41 Mod 0 was achieved in September 1960 and production continued until June 1962. Approximately 500 bombs were produced. The weapon
527-536: The question of continuing the program was raised. One item raised in support of continuing the program was that the 10,000-pound (4,500 kg) bomb could replace the 17,500-pound (7,900 kg) Mark 36 bomb. Another proposal was to delay the program and include a full-fuzing (FUFO) capability into the weapon that would allow for laydown delivery. However, in September 1958, the Radiation Laboratory and Sandia informed Field Command that to add FUFO to
558-415: The tallest tower tests to date in the U.S. nuclear testing program as well as high-altitude balloon tests. One nuclear test involved the largest troop maneuver ever associated with U.S. nuclear testing. Approximately 18,000 members of the U.S. Air Force , Army , Navy and Marines participated in exercises Desert Rock VII and VIII during Operation Plumbbob. The military was interested in knowing how
589-460: The title W41 . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=W41&oldid=1174039994 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages W41 (nuclear warhead) In June 1955,
620-708: The use of the existing Bassoon device that was test fired in the Zuni and Tewa shots of Operation Redwing . Stockpiling of this new weapon was planned for January 1959. Dirty and clean (low fission fraction) versions of the device were proposed, with the clean version being dependent on a nuclear test in Operation Hardtack I . The nomenclature of TX-41 and XW-41 was assigned to the weapon in November 1956, and in December plans were made to conduct drop tests of
651-455: The various flight stresses. Fuzing would include contact and air-burst modes, and would be selectable in flight. Contact fuzing would act as a backup for airburst fuzing and a parachute to slow the rate of fall would be developed. Compatibility with the Navaho missile and B-58 bomb pod was also requested. By March 1957, it was decided to place equal emphasis on the clean and dirty versions of
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#1732793599253682-534: The weapon from the B-47 bomber . A laydown version of the bomb was requested, however development of such a weapon would add 1 to 2 more years to its development. A non-laydown weapon was subsequently requested. The weapon's military characteristics were approved in February 1957. The weapon was to be carried by the B-47, B-52 , B-66 and systems 110A and 125A . The bomb would be able to withstand without damage
713-443: The weapon would require a completely new weapon, including nuclear testing. In November 1958 it was decided that the weapon would always be deployed in the parachute retarded condition, and thus an option selector switch was no longer needed. In December, Sandia raised issues with the safety of the weapon and proposed additional safing devices. This was provided with additional switches in the aircraft monitor station. In January 1959,
744-587: The weapon. By this point the weapon was to be 50 inches (1,300 mm) in diameter, with a warhead length of 120 inches (3,000 mm) and weight of 9,300 pounds (4,200 kg), while the bomb was to have a length of 145 inches (3,700 mm) and weigh 10,000 pounds (4,500 kg). Compatibility with the B-58 was canceled in May 1957, and the warhead version of the weapon was canceled in July 1957. In July 1957, tests of
775-400: Was 9.3 megatonnes of TNT (39 PJ). Pine was a three-stage variant of the clean device, with a predicted yield of 4 to 6 megatonnes of TNT (17 to 25 PJ), but the test only yielded 2 megatonnes of TNT (8.4 PJ). In June 1958, the requirement to be able to select air and ground burst fuzing modes from the cockpit was canceled. This change meant that fuzing selection had to be made on
806-797: Was a series of nuclear tests that were conducted between May 28 and October 7, 1957, at the Nevada Test Site , following Project 57 , and preceding Project 58/58A . The operation consisted of 29 explosions , of which only two did not produce any nuclear yield . Twenty-one laboratories and government agencies were involved. While most Operation Plumbbob tests contributed to the development of warheads for intercontinental and intermediate range missiles , they also tested air defense and anti-submarine warheads with smaller yields. They included 43 military effects tests on civil and military structures, radiation and bio-medical studies, and aircraft structural tests. Operation Plumbbob had
837-468: Was asked to examine whether nuclear detonations could be conducted underground. The first subterranean test was the nuclear device known as Pascal A, which was lowered down a 500 ft (150 m) borehole. However, the detonated yield turned out to be 50,000 times greater than anticipated, creating a jet of fire that shot hundreds of meters into the sky. During the Pascal-B nuclear test of August 1957,
868-418: Was focused on the borehole because studying the velocity of the plate was deemed scientifically interesting. After the detonation, the plate appeared in only one frame. Regarding its speed Brownlee reckoned that "a lower limit could be calculated by considering the time between frames (and I don't remember what that was)", and joked that the best estimate was it was "going like a bat !". Brownlee estimated that
899-514: Was replaced by the more versatile B53 bomb between November 1963 and July 1976. The weapon was 12 ft 4 in (3.76 m) long, with a body diameter of 4 ft 4 in (1.32 m). It weighed 10,670 lb (4,840 kg). It was carried only by the B-52 Stratofortress and B-47 Stratojet . It could be deployed in free-fall or retarded free-fall, and had both air burst and ground burst fuzing. The weapon did not have
930-408: Was subsequently tested in shots Sycamore, Poplar and Pine of Hardtack I in 1958. Sycamore, a clean test, was a fizzle, producing only 92 kilotonnes of TNT (380 TJ) instead of the predicted 5 megatonnes of TNT (21 PJ). Poplar was a retest of Sycamore with a predicted yield of 5 to 10 megatonnes of TNT (21 to 42 PJ) and only 200 kilotonnes of TNT (840 TJ) fission yield. The actual yield
961-410: Was the first fully contained underground nuclear test, meaning that no fission products were vented into the atmosphere. This test of 1.7 kt could be detected around the world by seismologists using ordinary seismic instruments. The Rainier test became the prototype for larger and more powerful underground tests. Images from Upshot-Knothole Grable were accidentally relabeled as belonging to