B43 (nuclear weapon)

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A B43 nuclear weapon

The B43 was a hydrogen bomb that was designed as a free-falling aerial bomb with a variably selectable explosive force . It was put into service in 1961 and was developed for the strategic deployment concept.

development

The B43 was created in response to a request from the United States Armed Forces in 1956. They needed a nuclear free-fall bomb that could be used by high-speed aircraft ( bombers and fighter jets ). The bomb should be dropped both from a great height and from low altitude . Development began in 1955 at the Los Alamos National Laboratory in New Mexico . The B43 was u. A. Tested several times in 1958 during Operation Hardtack and in 1962 during Operation Dominic . The first models were delivered to the United States Armed Forces in 1961.

construction

bomb

The B43 was designed to combat hardened targets such as underground bunkers and missile silos . Two different types of bombs were made of the B43, both using the same W43 nuclear warhead. The bombs differed in the shape of the bomb tip and their deployment concept. The version B43 Mod 0 was intended for dropping from low altitude. The B43 Mod 1 version could be used from different flight altitudes. The B43 had a streamlined bomb shell and could be carried in a weapon bay or at external load stations . For this, the B43 was equipped with the standard bomb locks with 762 mm. The B43 bombs can be roughly divided into three sections. The ignition system was housed in the top of the bomb. Depending on the version, this included a time fuse , an impact fuse or a proximity fuse . The W43 nuclear warhead and its operating elements were housed in the middle section. Four stabilizing wings were mounted on the rear of the bomb. A parachute / braking parachute was also housed in the rear of the bomb .

Nuclear warhead

The B43 was equipped with the W43 nuclear warhead. The W43 nuclear warhead was a hydrogen bomb based on the Teller-Ulam design . The primary nuclear fission explosive device of the "Tsetse" type was used for the B43. This fission fuse was a boosted fissure bomb . This consisted of a hollow sphere made of 2.25  kg of 239 plutonium and filled with 6  g of tritium . This sphere was encased in a layer of 235 uranium weighing 1.4 kg . Explosive lenses made of polymer-bound explosives of the type PBX-9504 were used to detonate this primary nuclear fission explosive device. Next to the spherical nuclear fission explosive device was the cylindrical fusion stage. In this u. A. Lithium deuteride and tritium used. The W43 nuclear warhead was designed so that the explosive force could be selected in four stages. Of these four levels, three are known: 70  kT , 500 kT or 1.0 MT. The selection of the explosive power had to be done on the ground before the aircraft took off. In order to prevent accidental detonation or improper ignition, the nuclear warhead of the B43 was equipped with the Permissive Action Link .

variants

B43 Mod 0

The B43 Mod 0 was designed for use at high speed from low altitude. It also had a blunt bomb tip to which a spike made of high-strength steel was attached. This stinger was supposed to dig into the ground when it hit the ground and thus prevent the bomb from ricocheting and sliding. During the transport on the aircraft, a ballistic hood was attached over the blunt bomb tip and the spike . After the drop from a height of at least 90 m, the parachute / braking parachute opened and slowed the fall of the bomb. When the parachute was opened, the ballistic hood was also blown off the top of the bomb and the sting was exposed. After being dropped from the aircraft, the time fuse for the W43 nuclear warhead was activated. The detonator was set in such a way that the aircraft had sufficient time to fly out of the effective area of ​​the nuclear weapon explosion . The only operational concept available for the B43 Mod 0 was the delayed ignition after being dropped from low altitude ("laydown" drop).

bomb length diameter span Weight
B43 Mod 0 3.80 m 460 mm 860 mm 936 kg

B43 Mod 1

Compared to the B43 Mod 0 version, the B43 Mod 1 had an extended bomb tip without a spike. An impact fuse, radar distance fuse and a time fuse were housed in the top of the bomb . The rest of the bomb structure was identical (including parachute / braking parachute). The B43 Mod 1 could be used in a wide range of applications:

  • free-falling height ignition (from a great height)
  • Altitude ignition after delay by parachute (from high and medium altitude)
  • free-falling impact ignition (from high and medium height)
  • Impact ignition after delay by parachute (from high and medium height)
  • delayed ignition after dropping from the climb (pulling up from the low flight - "toss" or "loft" drop)
bomb length diameter span Weight
B43 Mod 1 4.16 m 460 mm 860 mm 964 kg

status

The B43 was intended for use with the United States Air Force , Strategic Air Command , the United States Navy and NATO . Around 1000 B43s were produced between 1961 and 1970. From the mid-1980s, the B43 was eliminated and gradually replaced by the more modern B61 and B83 . The last B43 was removed from the United States' nuclear arsenal in 1995.

Emergency aircraft

Operation Broken Arrow

The B43 was never used as part of military operations. Nevertheless, there was a serious incident involving one of these bombs. On December 5, 1965, an A-4E Skyhawk equipped with a B43 from the aircraft carrier USS Ticonderoga was lost off the coast of Japan . The aircraft sank to the sea floor around 50 km off the island of Ryukyu / Okinawa at a depth of more than 5000 m. The Skyhawk was supposed to be rolled from the hangar onto the elevator on the aircraft carrier and fell into the sea. The pilot Lt. JG Webster was killed and his body was not found. The incident was kept secret from the public and did not come to light until 1981 when a Pentagon investigation report published the loss of a nuclear weapon with the explosive power of 1Mt TNT.

literature

  • Duncan Lennox: Jane's Strategic Weapon Systems . Edition 2001, 34th edition Edition, Jane's Information Group, 2001, ISBN 0-7106-0880-2 .

Web links

Commons : B43  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ a b c d e f g h i j k Duncan Lenox: Jane's Strategic Weapon Systems, Edition 2001. 2001. P. 598.
  2. ↑ a b c Complete List of All US Nuclear Weapons. In: nuclearweaponarchive.org. The Nuclear Weapon Archive, October 14, 2006, accessed October 1, 2018 .
  3. ↑ AWPAC / 8/5. In: nuclear-weapons.info. British Nuclear Weapons, accessed October 1, 2018 .
  4. ↑ Maggelet, Michael H., and Oskins, James C., "Broken Arrow: The Declassified History of US Nuclear Weapons Accidents," Lulu Publishing, www.lulu.com, 2007, ISBN 978-1-4357-0361-2 , chapter 29, page 217.
  5. ↑ Gibson, James N. Nuclear Weapons of the United States - An Illustrated History Atglen, Pennsylvania .: Schiffer Publishing Ltd., 1996, Library of Congress card no. 96-67282, ISBN 0-7643-0063-6 , page 130.
  6. ↑ Winchester, Jim, Douglas A-4 Skyhawk: Heineman's Hot Rod . Barnsley, Yorkshire, United Kingdom: Pen & Sword Books, 2005, ISBN 1-84415-085-2 , page 199.
  7. ↑ Archive link ( Memento from December 6, 2010 in the Internet Archive )
  8. ↑ http://www.atomicarchive.com/Almanac/Brokenarrows_static.shtml
  9. ↑ Washington, DC: Washington Post, Reuter, " US Confirms '65 Loss of H-Bomb Near Japanese Islands, " Tuesday May 9, 1989, page A-27.
  10. ↑ Washington, DC: Washington Post, " Japan Asks Details On Lost H-Bomb, " Wednesday May 10, 1989, page A-35.