B61 Family
Encyclopedia
The B61 Family is a series of thermonuclear bombs and thermonuclear warheads based on the B61 nuclear bomb
B61 nuclear bomb
The B61 nuclear bomb is the primary thermonuclear weapon in the U.S. Enduring Stockpile following the end of the Cold War. It is an intermediate yield strategic and tactical nuclear weapon featuring a two-stage radiation implosion design....

.

Initial development

The B61 bomb was developed by Los Alamos Scientific Laboratory (LASL; now Los Alamos National Laboratory
Los Alamos National Laboratory
Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...

) starting in 1960. The intent was to develop an aircraft bomb which was high yield
Nuclear weapon yield
The explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene , either in kilotons or megatons , but sometimes also in terajoules...

 (up to over 100 kilotons) and yet was small enough and had low enough drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...

 to carry under the wing of a fighter
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

 or fighter-bomber
Fighter-bomber
A fighter-bomber is a fixed-wing aircraft with an intended primary role of light tactical bombing and also incorporating certain performance characteristics of a fighter aircraft. This term, although still used, has less significance since the introduction of rockets and guided missiles into aerial...

 type aircraft. One major feature was Full Fuzing Options (allowing various air and ground burst usage options; free fall air burst
Air burst
An air burst is the detonation of an explosive device such as an anti-personnel artillery shell or a nuclear weapon in the air instead of on contact with the ground or target or a delayed armor piercing explosion....

, parachute
Parachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon...

 retarded air burst, free fall ground burst
Ground burst
A groundburst is the detonation of an explosive device such as an artillery shell, nuclear weapon or air-dropped bomb that explodes upon hitting the ground...

, parachute retarded ground burst, and laydown or parachute retarded time delay after impact ground burst).

The B61 project started in 1960 with a study contract analyzing the potential of such a weapon. The official development program was funded in 1961, and the weapon was designated TX-61 (Test/Experimental) in 1963.

The original models of B61 used PBX 9404 HMX
HMX
HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the name has been variously listed as High Melting eXplosive, Her Majesty's eXplosive, High-velocity Military eXplosive, or High-Molecular-weight rdX.The molecular...

 based plastic bonded explosive. Newer models use TATB
TATB
TATB, or triaminotrinitrobenzene, is an aromatic explosive, based on the basic six-carbon benzene ring structure with three nitro functional groups and three amine groups attached, alternating around the ring....

 based PBX 9502, which is an insensitive high explosive (IHE) and will not detonate due to fire, shock, or impact.

Bomb

The overall B61 bomb was 13.3 inches (337.8 mm) diameter by 141 inches (3,581.4 mm) long, and weighed 695-715 pounds depending on version. This includes the outer aerodynamic shell, a crushable nose cone
Nose cone
The term nose cone is used to refer to the forwardmost section of a rocket, guided missile or aircraft. The cone is shaped to offer minimum aerodynamic resistance...

, parachute section in the tail, tail fin
Fin
A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...

s, etc. (Weight includes tail fins; diameter is of the bomb body itself, without fins).

Nuclear core

The nuclear device within the outer B61 core is probably the same overall dimensions as the W80 warhead, which is 11.8 inches (299.7 mm) in diameter and 31.4 inches (797.6 mm) long.

W69
W69
W69 is a United States nuclear warhead used in AGM-69 SRAM Short-Range Attack Missiles.It was designed in the early 1970s and produced from 1974 to 1976. It remained in service until 1991, with the last units being retired in 1996...

The W69 missile warhead
Warhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...

 was produced in the early 1970s for use in the AGM-69 SRAM
AGM-69 SRAM
The Boeing AGM-69 SRAM was a nuclear air-to-surface missile designed to replace the older AGM-28 Hound Dog stand-off missile....

 Short Range Attack Missile. The W69 was 15 inches (381 mm) in diameter and 30 inches (762 mm) long, weighed 275 pounds, and had a yield of 170-200 kilotons.

1,500 W69 warheads were produced.

W73
W73
The W73 was an American nuclear warhead for the AGM-53 Condor air to surface missile.The W73 was cancelled in 1970 in favor of a purely conventional warhead for the Condor. None were produced....

The W73 missile warhead was designed for the AGM-53 Condor
AGM-53 Condor
In 1962, the U.S. Navy issued a requirement for a long-range high-precision air-to-surface missile. The missile, named the AGM-53A Condor, was to use a television guidance system with a data link to the launching aircraft similar to the system of the then projected AGM-62 Walleye.-Development...

 air to ground missile. Other than being described as a derivative of the B61, details of the W73 design are poorly documented.

Both the W73 and the Condor missile were cancelled and never entered service.

W80

Two versions of the base W80 cruise missile
Cruise missile
A cruise missile is a guided missile that carries an explosive payload and is propelled, usually by a jet engine, towards a land-based or sea-based target. Cruise missiles are designed to deliver a large warhead over long distances with high accuracy...

 warhead were designed and deployed. Both were the same basic size and shape and weight: 11.8 inches in diameter, 31.4 inches long, and weight of 290 pounds.

W80-0

The BGM-109 Tomahawk
BGM-109 Tomahawk
The Tomahawk is a long-range, all-weather, subsonic cruise missile. Introduced by General Dynamics in the 1970s, it was designed as a medium- to long-range, low-altitude missile that could be launched from a surface platform. It has been improved several times and, by way of corporate divestitures...

 TLAM-N cruise missile was equipped with a W80-0 warhead. The W80-0 used supergrade plutonium with less inherent radioactivity, due to missile storage in close proximity to submarine crew. It also has an outer shielding or case around the "front" end of the weapon, presumably some sort of radiation shielding. The W80-0 had a variable yield
Variable yield
Variable yield — or dial-a-yield — is an option available on most modern nuclear weapons. It allows the operator to specify a weapon's yield, or explosive power, allowing a single design to be used in different situations...

 of 5 or 170-200 kilotons.

367 W80-0 warheads were produced.

W80-1

The ALCM and ACM
AGM-129 ACM
* Missile of the same class** Ra'ad ** TAURUS KEPD 350 ** Storm Shadow -Notes:# Alleged violations of the Antideficiency Act in the Air Force’s procurement of advanced cruise missiles.FILE B-255831, Office of the General Counsel, United States General Accounting Office.# Union Calls for Strike by...

 cruise missiles used the W80-1 variant warhead. It had a yield of 5 or 150-170 kilotons.

1,750 W80-1 warheads were produced.

W81
W81
The W81 thermonuclear warhead was a planned US warhead to be mounted on the SM-2 surface to air missile used by the US Navy. The W81 was a design derivative of the B61 nuclear bomb as many other modern US warhead designs are...

The W81 missile warhead was designed for use on the SM-2
Standard missile
Standard Missile can refer to a family of several different American missiles:* RIM-66 Standard , a medium range surface-to-air missile, the successor of the RIM-24 Tartar missile...

 missile. An enhanced radiation
Neutron bomb
A neutron bomb or enhanced radiation weapon or weapon of reinforced radiation is a type of thermonuclear weapon designed specifically to release a large portion of its energy as energetic neutron radiation rather than explosive energy...

 version was proposed, but the final version was fission-only. Detailed dimensions and weight are unknown. Yields are described as 2-4 kilotons.

The W81 was cancelled and never entered service.

W84
W84
The W84 is an American thermonuclear warhead designed for use on the BGM-109G Gryphon Ground Launched Cruise Missile . It is a derivative of the B61 nuclear bomb design and a close relative of the W80 warhead used on the AGM-86 ALCM, AGM-129 ACM, and BGM-109 Tomahawk SLCM cruise missiles.The W84...

The W84 was a LLNL design based on the B61, used in the Ground Launched Cruise Missile
Ground Launched Cruise Missile
The Ground Launched Cruise Missile, or GLCM, was a ground-launched cruise missile developed by the United States Air Force in the last decade of the Cold War.-Overview:...

. It was slightly larger (13 inches diameter, 34 inches long) and heavier (388 pounds) than the otherwise similar W80 warheads, possibly to make it safer for ground handling in the field.

Between 300 and 350 W84 warheads were produced. They remain in US inactive inventory.

W85
W85
The W85 was a thermonuclear warhead developed by the United States of America to arm the Pershing II missile. It had a variable yield— often referred to as "dial-a-yield" — which could be set between 5 and 80 kilotons.-Overview:...

Used on the Pershing II IRBM missile, the W85 was a cylinder 13 inches (330.2 mm) in diameter and 42 inches (1,066.8 mm) long. The warhead weighed 880 pounds. It had a variable yield from 5 to 80 kilotons.

120 W85 warheads were produced. They were recycled into B61 Mod 10 bombs after the Pershing II was scrapped.

W86
W86
The W86 was an American thermonuclear warhead with earth-penetrating characteristics which was intended for use on the Pershing II IRBM missile....

The W86 warhead was a planned earth-penetrating
Nuclear bunker buster
Bunker-busting nuclear weapons, also known as earth-penetrating weapons , are a type of nuclear weapon designed to penetrate into soil, rock, or concrete to deliver a nuclear warhead to a target. These weapons would be used to destroy hardened, underground military bunkers buried deep in the ground...

 warhead for the Pershing II missile. The W86 was cancelled after the Pershing II was changed from hard target to soft target
Soft target
Soft target is a military term referring to unarmored/undefended targets needing to be destroyed. For example, a soft target would be an automobile, a house, or assembly of people while a hard target could be a main battle tank or a well defended installation...

missions in its design phase.

No units were ever produced.
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