Mark VI Aerial Bomb By Developed in 1949, the Mark VI Aerial Bomb was basically an improved version of the "Fat Man" bomb that was 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. TECHNICAL NOTES: Length: 10 ft. 7 in. Diameter: 60 in. Weight: 8500 lbs. Yield: Kiloton range (One kiloton equals 1,000 tons of TNT) Click here to return to the Cold War Gallery. Find Out More Related Fact Sheets "Fat Man" Atomic Bomb Boeing B-29 Superfortress Convair B-36J Peacemaker Boeing RB-47H Stratojet Boeing WB-50D Superfortress Boeing B-52D Stratofortress Note: The appearance of hyperlinks does not constitute endorsement by the National Museum of the USAF, the U.S. Air Force, or the Department of Defense, of the external website, or the information, products or services contained therein.