Turret
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Image:Turret (architecture) 1.jpg Image:Newark Castle turrets.jpg
In architecture, a turret (from Italian: torretta, little tower; Latin: turris, tower) is a small tower that projects from the wall of a building, such as a medieval castle or baronial house. A building may have both towers and turrets; turrets might be smaller or higher but the difference is generally considered to be that a turret projects from the edge of the building, rather than continuing to the ground. The size of a turret is therefore limited by technology, since it puts extra stresses into the frame of the house. It would traditionally be supported by a corbel.
A turret might have a flat top with crenellations as in the picture, a pointed roof, or any other kind of top. It might contain a staircase if it projects higher than the building. However, a turret might not be any higher than the rest of the building; in this case it is part of a room, that can be simply walked into – see the turret of Chateau de Chaumont on this collection of turrets, which also illustrates a turret on a modern skyscraper.
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Gun turrets
Turret may also refer to a rotating weapon platform, mounted on a fortification, armoured fighting vehicle, naval ship, or military aircraft. A turret may be armed with one or more machine guns, automatic cannon, large-calibre guns, or missile launchers. It may be manned or remotely controlled, and often armoured. A small turret, or sub-turret on a larger one is called a cupola.
Aircraft
At first guns on aircraft where either fixed in orientation or mounted on simple swivel mounts. The latter evolved into a rotating ring mount which meant the gun could be turned to any direction with the gunner remaining directly behind it. As aircraft flew higher and faster, the need for protection from the elements led to the enclosure or shielding of the gun positions. The first bomber in the Royal Air Force to cary a power operated turret, was the Boulton Paul Overstrand flying for the first time in 1933. The Overstrand had a single turret which was at the front of the bomber fitted with one machine gun. In time the number of turrets carried and the number of guns mounted increased. RAF heavy bombers of the Second World War typically had 3 powered turrets, with the rear one - the "Tail End Charlie" position - mounting four 0.303 inch machine guns.
The UK tried the concept of the "turret fighter" where the main armament of the fighter was not in fixed positions in the wings but in a turret mounted behind the pilot. Though the idea had merits it was found to impracticable. The turret on bombers fell from favor with the advent of the jet age, though the Boeing B-52 jet bomber and many of its contemporaries featured a tail mounted barbette - a form of turret but with more limited field of fire.
Armoured fighting vehicles
In a modern main battle tank, the turret (which is armoured for crew protection) rotates a full 360 degrees and carries a single large-calibre tank gun (typically in the range 105 mm to 125 mm calibre). The turret houses two or more crewmen, typically a tank commander, gunner and often a gun loader).
Warships
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Image:Battleship turret layout.PNG
Among the earliest cases of turret gun ships was the USS Monitor, which mounted two cannons in a fully rotating armoured drum. This style existed alongside a static drum, the barbette, inside which the gun mount rotated - the gun barrel projecting over the edge of the drum. The latter design then developed an armoured portion that sat over the gun and the edge of the barbette leading to the term "hooded barbette". It was not until the last of the rotating drum designs was phased out that the hooded barbette arrangement - which is the style associated with modern battleships - took the name "turret". The rotating part of a battleship turret is the "gunhouse" where the guns are loaded. Below the gunhouse are the loading hoists that bring ammunition up from the magazines to the gunhouse. The handling equipment and hoists can be complex arrangements of machinery. They have to take the shells and propelling charges from their magazines into the base of the turret. There they have to be lined up with the hoists which are fixed in orientation to the guns. The hoists then lift the ammuniton up to the gunhouse where the shells and the appropriate charge are mechanically loaded into each gun breech. The barbette is armoured down to where it reaches the main armoured deck of the warship.
Some modern warships still have turrets with guns - though these are less important to the ship with modern missile systems. These turrets are often just covers for the gun mounting equipment made of light unarmoured materials such as fibreglass
Naming
On board warships, each turret is given an identification. In British use, these would be letters: "A," "B," "C," etc. for the turrets from the front of the ship backwards, and letters near the end of the alphabet (i.e., "X," "Y," etc.) for turrets in the rear of the ship. Mounts in the middle of the ship would be "Q," "R," etc. In one instance, a battleship's turrets were named "Monday," "Tuesday," etc. up to "Sunday." In German use, turrets were generally "A," "B," "C," "D," "E" going backwards from stem to stern. This lent more opportunity for using names instead of letters, e.g. "Caesar," "Dora" as on the German battleship Bismarck.