Type Conventional high explosive bomb Place of origin United States Service history In service 1945 Used by United States Army Air Forces Wars World War II Production history

Number built 486

Specifications

Weight 5.26 long tons (5.89 short tons; 5.34 t)
Length 12 feet 5 inches (3.78 m)
Diameter 60 inches (152 cm)
Filling Composition B Filling weight 6,300 pounds (2,900 kg)

Pumpkin bombs were conventional high-explosive aerial bombs developed by the Manhattan Project and used by the United States Army Air Forces against Japan during World War II. The pumpkin bomb was a close but non-nuclear replication of the Fat Man plutonium bomb with the same ballistic and handling characteristics. It was mainly used for testing and training purposes, but combat missions were also flown with pumpkin bombs by the 509th Composite Group. The name "pumpkin bomb" resulted from the large ellipsoidal shape of the munition and was the actual reference term used in official documents.

Development
Pumpkin bombs were a means of providing realistic training for the 509th Composite Group's Boeing B-29 Superfortress crews assigned to drop the atomic bomb after their deployment to the Pacific. The pumpkin bomb was a close but non-nuclear replication of the Fat Man plutonium bomb with the same ballistic and handling characteristics. Specifications for the bomb required that it be carried in the forward bomb bay of a Silverplate B-29 bomber and be fuzed to be effective against actual targets.

Description
The pumpkin bombs were externally similar to the Fat Man bomb in size and shape, and both had the same 52" California Parachute square tail assembly and single-point attachment lug. The pumpkin bomb had three contact fuzes arranged in an equilateral triangle around the nose of the bomb while the atomic bomb had four fuse housings. The atomic bomb had its sections bolted together but most if not all of the pumpkin bombs were welded with a hole used for filling the shell. The Fat Man also had four external mounting points for radar Antenna (radio)|antennae which the pumpkin bombs did not have.

The pumpkin bombs were 12'08" in length and 60" in maximum diameter.  They weighted consiting of 3800.lb for the shell, 425.lb for the tail assembly and 6300.lb of  Composiiton B filler