Mark 6 Nuclear Bomb
The Mark 6 "60-inch nuclear bomb" was the first atomic bomb to be mass produced by the United States. It was designed to be delivered by the heavy bombers of the Strategic Air Command and employed against strategic military targets only. The first version of the bomb was developed beginning in 1949 and first deployed in 1951. Several models of the Mark 6 were produced before it was finally removed from the nuclear stockpile in 1957. The Mark 6 did serve, however, as the basis for the development of the Mark 18 nuclear weapon in the mid-1950s.
This weapon was a capsule bomb, meaning that the nuclear material for the bomb was kept in a special capsule separate from the rest of the device for safety's sake. Just before the bomb was to be dropped from the delivery aircraft the capsule was inserted into the bomb casing and the weapon became armed. It was also the first atomic weapon to offer the delivery aircraft's bombardier the option of changing the detonation altitude while the bomber was in flight to the target.
The Mk 6 looks almost identical to the Mk 4, from which it was developed. The greatest weight savings were realized by replacement of the heavy steel bomb case and sphere with ones made from aluminum. Inside the 61"x128" aluminum case, many changes have been made. Below the safing plugs, an easy to remove nose plate permits access to the horn type radar antenna, and allows for simpler and quicker inflight insertion. Redesign of the entrance to the pit, addition of a detonator holding trap door, and coring of the high explosives, makes it possible to slide the outer and inner cores of HE into a rotatable holder, and permits manual IFI to be accomplished in a minimum of time. A single lug at the top of the ballistic case is used to suspend this 8500 lb weapon from the bomb bay of the delivery aircraft, and extending through the skin are the arming wires that operate the pullout switches upon release.
This easy to remove cartridge is the electrical and electronic heart of the weapon, readily accessable are the batteries, the radars, and barometric switches of the fuzing system. The gap tubes, and detonator contacts of the x-unit are on the face of the cartridge, and inside the weapon is the detonator distribution system, with it's loading coils to equalize the electrical paths to the detonators. When the cartridge is inserted into the weapon, pressure contact provides the connection between firing system and the terminals of the detonation system.
The Mark 6 produced a far greater yield than the 23-kiloton "Fat Man" bomb, but weighed less and was more aerodynamically stable and therefore more accurate. However, the Mark 6 required a great deal of very expensive nuclear material to produce its explosive yield. Therefore, with the advent of thermonuclear weapons, which required only a minimum amount of nuclear material to generate a massive explosion, Mark 6 bombs were removed from the inventory and their nuclear material recycled into the more powerful H-bombs.
USAF aircraft that carried the Mark 6 were the B-29, B-50, B-36, B-47, and B-52. The U.S. Navy also carried the bomb on its AJ-1 aircraft.
|Length:||10 ft 8 in|
|Diameter:||5 ft 1 in|
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