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A disappearing gun, a gun mounted on a ''disappearing carriage'', is an obsolete type of artillery which enabled a gun to hide from direct fire and observation. The overwhelming majority of carriage designs enabled the gun to rotate backwards and down behind a parapet, or into a pit protected by a wall after it was fired; a small number were simply barbette mounts on a retractable platform. Either way, retraction lowered the gun from view and direct fire by the enemy while it was being reloaded. It also made reloading easier, since it lowered the breech to a level just above the loading platform, and shells could be rolled right up to the open breech for loading and ramming. Some disappearing carriages were complicated mechanisms, protection from aircraft observation and attack was difficult, and almost all restricted the elevation of the gun. With a few exceptions, construction of new disappearing gun installations ceased by 1918. The last new disappearing gun installation was a solo 16-inch gun M1919 at Fort Michie on Great Gull Island, New York, completed in 1923. In the U.S., due to lack of funding for sufficient replacements, the disappearing gun remained the most numerous type of coast defense weapon until replaced by improved weapons in World War II.〔(Complete list of US forts and batteries at CDSG website )〕〔Berhow, pp. 200-228〕 Although some early designs were intended as field siege guns, over time the design became associated with fixed fortifications, most of which were coastal artillery. A surprising late exception was the use in mountain fortifications in Switzerland, where six 120mm guns on rail-mounted Saint Chamond disappearing carriages remained at Fort de Dailly until replaced in 1940. The disappearing gun was usually moved down behind the parapet or into its protective housing by the force of its own recoil, which (on many models) lifted a counterweight. Before firing, the crew tripped a catch on the counterweight, causing it to fall and move the gun back up "into battery" (firing position). Some disappearing guns also used compressed air,〔(Disappearing Guns ) (from the Royal New Zealand Artillery Old Comrades Association)〕 while a few were built to be raised by steam.〔(The Defenses of Sandy Hook ) (from a Sandy Hook, Gateway National Recreation Area, U.S. National Park Service information pamphlet. Accessed 2008-02-22.)〕 == History == Captain (later Colonel Sir) Alexander Moncrieff, improved on existing designs for a gun carriage capable of rising over a parapet before being reloaded from behind cover. His design, based on his observations in the Crimean War was the first widely adopted. The first experimental carriages of this type were wheeled.〔(Hydropneumatic carriages at Victorian Forts and Artillery )〕 His key innovation was a practical counterweight system that raised the gun as well as controlled the recoil. Moncrieff promoted his system as an inexpensive and quickly constructed alternative to a more traditional gun emplacement.〔("Moncrieff's method of mounting guns with counterweights, of using them in gun-pits, and of laying them with reflecting sights : a paper read at the Royal United Service Institution (1866)" ) (from archive.org. Accessed 2009-06-25.)〕 The usefulness of such a system had been noted earlier, and experimental designs with raisable platforms or eccentric wheels, with built-in counterweights, were built or proposed. Some used paired guns, in which one cannon acted as the other's counterweight. An unsuccessful attempt at a disappearing carriage was King's Depression Carriage, designed by Rufus King, Jr. of the United States Army in the late 1860s. This used a counterweight to allow a 15-inch (381 mm) Rodman gun to be moved up and down a swiveling ramp, so the weapon could be reloaded, elevated, and traversed behind cover. It was not adopted. Part of a test installation at Fort Foote, Maryland remains.〔(King's Depression Carriage at the Historical Marker Database )〕 King's design was better suited for breech-loaders; had the US not had a plethora of new muzzle-loaders just after the Civil War it may have seen wider use. Buffington and Crozier further refined the concept in the late 1880s by allowing the ounterweight fulcrum to slide, giving the gun a more elliptical recoil path. The Buffington–Crozier Disappearing Carriage (1893) represented the zenith of disappearing gun carriages,〔 and guns of up to 16-inch size were eventually mounted on such carriages. Disappearing guns were highly popular for a while in the British Empire, the United States and other countries. In the United States, they were the primary armament of the Endicott- and Taft-era fortifications, constructed 1898-1917. Simpler carriages with a limited disappearing function were initially provided for smaller weapons, the balanced pillar for 5-inch guns and the masking parapet for 3-inch M1898 guns. However, these were found to interfere too much with the rate of fire and were soon disabled in the "up" position, with new installations receiving pedestal mounts.〔Berhow, pp. 70-71, 88-89〕 Several mobile disappearing mounts appeared in France and Germany circa 1893. These included both road-mobile and rail-mobile designs. In France, Schneider produced a road-mobile design and St. Chamond a rail-mobile design, both for 120 mm (4.7 inch) weapons. Six 120 mm Modèle 1882 guns on St. Chamond mounts were deployed at Fort de Dailly in Switzerland from 1894 to 1939.〔(Fort de Dailly at ASMEM (Association St-Maurice d'Etudes Militaires) (in French) )〕〔(''La Mechanique a l'Exposition de 1900'', Vol. 3, No. 15, p. 87 (in French) )〕 Krupp produced a rail-mobile 120 mm disappearing gun in 1900.〔(Dillard, Col. James B., "Railway Artillery", ''Mechanical Engineering'', Vol. 41, Issue 1, January 1919, p. 44 )〕 Though effective against ships, the guns were vulnerable to aerial observation attack. After World War I coastal guns were usually casemated for protection or covered with camouflage for concealment.〔(【引用サイトリンク】 title=Fort Winfield Scott: Battery Lowell Chamberlin )〕 By 1912, disappearing guns were declared obsolete in the British Army, with only a few other countries, particularly the United States, still producing them up to World War I〔 and retaining them in service until replaced by casemated batteries in World War II.〔〔 The only major campaign in which US disappearing guns played a part was the Japanese invasion of the Philippines, which began shortly after the attack on Pearl Harbor on 7 December 1941 and ended with the surrender of US forces on 6 May 1942. The disappearing guns were the least useful of the coast defense assets, as they were positioned to defend against warships entering Manila Bay and Subic Bay and in most cases could not engage Japanese forces due to limited traverse. Despite attempts at camouflage, their emplacements were vulnerable to air and high-angle artillery attack. 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「Disappearing gun」の詳細全文を読む スポンサード リンク
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