The Mark VI Atomic Bomb


Weighing in at approximately 8500 pounds and measuring 5 feet 1 inch in diameter and 10 feet 8 inches in length, our weapon was a rather sizeable object. The AJ Savage was designed precisely to carry this bomb. No carrier-based plane that the Navy had prior to the AJ was large enough to carry the missile. I do not have the exact measurement of the bomb bay of the AJ, but working from scale drawings I have computed that the bomb bay was approximately 16 feet long. The width of the bomb bay was just a little under 6 feet in a fuselage that was approximately 6 feet 4 inches wide. It was definitely a tight fit. I recall having to enter the bomb-bay and standing on the small platform that folded down underneath the bomb bay access hatch in order to perform the Inflight Insertion (IFI) of the capsule. There could have been at most three feet of space for me to work, with my feet on the small platform and my tail on the edge of the hatch. My tools, the nose plate when removed, and the cage that housed the capsule when not in the bomb all had to be placed on the deck behind me in the crew compartment. I quite honestly don't recall how I handled the portion of the explosive sphere that had to be removed in order to place the capsule.

In this file I am going to present you with some pictures and some text, all of which have been "borrowed"/"archived" from the web. I will give you the link back to the source, so that you can look at the original if you wish. There will also be at least one link to a site that was too large for me to in good conscience "archive." Even I have my limits.

To digress a moment before going to the topic at hand, I should like to comment on how much of the old Top Secret material that I studied in the summer of 1953 while a student at HATU in Norfolk is now freely available on the web. I lived at the Breezy Point BOQ, and attended classes in one of the big seaplane hangars (was it SP-1 or SP-2?). Together with my classmates ENS O. W. McGuire and ENS C. E. Meyers I sat sat through many lectures about the charges, the wiring, the hardware, etc. We were made to take notes, but each day as we left the compound, the notes were taken from us and placed in a safe. When we left the school at the end of four months, the notes were left behind. For almost half a century I dared not discuss with anyone what I knew. It looks like the Mark VI is no longer a secret.

The first file that I present to you is from http://www.globalsecurity.org/wmd/systems/mk6.htm

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. [Emphasis added. Kennth Jennings Wooster]

Length: 10 ft 8 in
Weight: 8,500 lbs
Diameter: 5 ft 1 in
Yield: 120-150 Kilotons
Mark 6 Nuclear Bomb

Judging from the aircraft in the background, the picture accompanying the above article must be an Air Force photo. My recollection of the fiberglass face plate on the Navy version was that the face plate was planar rather than the slightly convex one shown here.

The second file that I am going to share with you is from http://www.wpafb.af.mil/museum/arm/arm40.htm



Mark VI Aerial Bomb

Mark VI Aerial Bomb

Developed in 1949, the Mark VI Aerial Bomb was basically an improved version of the "Fat Man" bomb that the B-29 Bockscar dropped on Nagasaki, Japan , in 1945. An implosion bomb (involving implosion-triggered plutonium fission), it had a higher yield, was lighter, and had improved ballistic (flying) characteristics. It could be carried internally on B-29 , B-36 , B-47 , B-50 , and B-52 aircraft, and the bombardier could set the height above ground of the explosion while the aircraft was in flight. The Mark VI underwent seven modifications, Mod 0 to Mod 6, between 1951 and 1955. It was the first mass produced nuclear weapon. The last Mark VI was retired in 1962.

SPECIFICATIONS
Length:
10 ft. 7 in.
Diameter: 60 in.
Weight: 8500 lbs.
Yield: Kiloton range (One kiloton equals 1,000 tons of TNT)



The third file is from http://www.strategic-air-command.com/weapons/nuclear_bomb_chart.htm

Mk-6
Yield: 8-160 Kt
Fusing: Airburst or Contact
Number Produced: 1,100
Weight: 7,600-8,500 lbs.
Dimensions: 61" x 128"
The Mark 6 was an improved high-yield and lightweight Mk-4.  Could be configured to yield, 8, 26, 80, 154, or 160 kilotons.  It was produced from June 1951 through early 1955. It was retired in 1962.

Finally, I will direct you to a very lengthy site at http://members.aol.com/nucinfo/.

There probably is a lot more out on the web about the Mark VI, but that is enough for now.


Visit my Whatever happened to all the savages? page.

Visit my Accidents for which I do not know the BuNo page.

Return to my US Navy Page back at my old site.

File created: 29 July 2004.
File modified: 29 July 2004.