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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. Pumpkin bombs were produced in both inert and high explosive variants. The inert versions were filled with a cement-plaster-sand mixture that was combined with water to , the density of the Composition B used in the high explosive versions. The filler of both variants had the same weight and weight distribution as the inner sphere used in the plutonium bomb. The concept for the high explosive pumpkin bomb was originated in December 1944 by U.S. Navy Captain William S. Parsons, the head of the Ordnance Division at Manhattan Project's Los Alamos Laboratory, and United States Army Air Forces Lieutenant Colonel Paul W. Tibbets, the commander of the 509th Composite Group, the unit responsible for delivering the atomic bombs. Before this, testing was carried out with the inert version. The name "pumpkin bomb" was given to the test bombs by Parsons and Dr. Charles C. Lauritsen of the California Institute of Technology, who managed the development team. The name was used in official meetings and documents,〔 and probably referred to its large ellipsoidal shape. Although anecdotal sources attribute the naming of the bombs to painting them a pumpkin color, the bombs were painted olive drab or khaki. Photographs indicate that the units delivered to Tinian came painted in the same zinc chromate primer color (i.e., yellow) worn by Fat Man. While many Manhattan scientists expected that the development of the means of delivery of the atomic bomb would be straightforward, Parsons, with his experience of the proximity fuze program, expected that it would involve considerable effort. The test program was initiated on 13 August 1943 at the Naval Proving Ground in Dahlgren, Virginia, where a scale model of the Fat Man plutonium bomb was developed. On 3 March 1944, testing moved to Muroc Army Air Field, California. The initial tests demonstrated that the Fat Man assembly was unstable in flight, and that its fuzes did not work properly. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「pumpkin bomb」の詳細全文を読む スポンサード リンク
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