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An aircraft carrier is a warship designed to deploy and recover aircraft — in effect acting as a sea-going airbase. Aircraft carriers thus allow a naval force to project air power great distances without having to depend on local bases for land-based aircraft. Modern navies that operate such ships treat aircraft carriers as the capital ship of the fleet, a role previously played by the battleship. The change, part of the growth of air power as a significant part of warfare, took place during World War II. A battleship could fire hundreds of large caliber shells at a target and score possibly a dozen hits. Their maximum range was usually no more than thirty miles. However, an aircraft launched from a carrier could deliver "smart weapons" accurately at a range of over one hundred miles. Thus, the aircraft carrier could perform the original mission of the battleship, causing heavy damage to an enemy fleet at great distance and with superior accuracy. Due to the long range of the striking aircraft heavy armour was less of a requirement and because of this, for example during World War II, aircraft carriers were less expensive and time consuming to build than battleships. Unescorted carriers are considered vulnerable to attack by other ships, aircraft, submarines or missiles and therefore travel as part of a carrier battle group. Unlike other types of capital ships in the 20th century, aircraft carrier designs since World War II have been effectively unlimited by any consideration save budgetary, and the ships have ballooned in size accordingly: The large, modern ''Nimitz'' class of United States Navy carriers has a displacement nearly four times that of the World War II-era USS ''Enterprise''. Flight deck The key aspect of the aircraft carrier is that is in effect a runway at sea and modern aircraft carriers have a flat-top deck design that serves as a flight deck for take-off and landing of aircraft. Aircraft take off to the front, into the wind, and land from the rear. Carriers steam at speed, for example up to 35 knots (65 km/h), into the wind during take-off in order to increase the apparent wind speed, thereby reducing the speed of the aircraft relative to the ship. On some ships, a steam-powered catapult is used to propel the aircraft forward assisting the power of its engines and allowing it to take off in a shorter distance than would otherwise be required, even with the headwind effect of the ship's course. On other carriers, aircraft do not require assistance for take off — the requirement for assistance relates to aircraft design and performance. Conversely, when landing on a carrier, conventional aircraft rely upon a tailhook that catches on arrestor wires stretched across the deck to bring them to a stop in a shorter distance than normal. Other aircraft — helicopters and V/STOL (Vertical/Short Take-Off and Landing) designs — utilize their hover capability to land vertically and so require no assistance in speed reduction upon landing. Conventional ("tailhook") aircraft rely upon a landing signal officer (LSO) to control the plane's landing approach, visually gauging altitude, attitude, and speed, and transmitting that data to the pilot. Before the angled deck emerged in the 1950s, LSOs used colored paddles to signal corrections to the pilot. From the late 1950s onward, visual landing aids such as mirrors provided information on proper glide slope, but LSOs still transmit voice calls to landing pilots by radio. Since the early 1950s it has been common to direct the landing recovery area off to port at an angle to the line of the ship. The primary function of the angled deck landing area is to allow aircraft who miss the arresting wires, referred to as a "bolter", to become airborne again without the risk of hitting aircraft parked on the forward parts of the deck. The angled deck also allows launching of aircraft at the same time as others land. The above deck areas of the warship (the bridge, flight control tower, and so on) are concentrated to the starboard side of the deck in a relatively small area called an "island". Very few carriers have been designed or built without an island and such a configuration has not been seen in a fleet sized carrier. A more recent configuration, used by the British Royal Navy, has a 'ski-jump' ramp at the forward end of the flight deck. This was developed to help launch VTOL (or STOVL) aircraft (aircraft that are able to take off and land with little or no forward movement) such as the Sea Harrier. Although the aircraft are capable of flying vertically off the deck, using the ramp is more fuel efficient. As catapults and arrestor cables are unnecessary, carriers with this arrangement reduce weight, complexity, and space needed for equipment. The disadvantage of the ski jump — and hence, the reason this configuration has not appeared on American supercarriers — is the penalty that it exacts on aircraft size, payload and fuel load (and hence, range): Large, slow planes like the E-2 Hawkeye and heavily-laden strike fighters like the F/A-18E/F Super Hornet cannot use a ski jump because their high weight requires either a longer takeoff roll than is possible on a carrier deck (even on the large Russian aircraft carrier Kuznetsov, lightly-loaded Su-33 air superiority fighters require almost the entire length of the deck to take off) or catapult assistance. Common types Over the course of the last century there have been several types of aircraft carrier, some of which are now obsolete. They can be generally categorized as follows: Initial designs and inter-war developments World War II developments Some cruisers and capital ships of the inter-war years often carried a catapult launched seaplane for reconnaissance and spotting the fall of the guns. It was launched by a catapult and recovered by crane from the water after landing. These were highly successful during World War II; there were many notable successes early in the war as shown by HMS ''Warspite''’s Walrus during operations in the Norwegian fjords in 1940. The Japanese Rufe floatplane derived from the Zero was a formidable fighter with only a slight loss in flight performance, one of their pilots scored 26 kills in the Rufe; a score only bettered by a handful of American pilots throughout WW2. Other Japanese seaplanes launched from tenders and warships sank merchant ships and small-scale ground attacks. The culmination of the type was the American 300+ mph Curtis SC-1 SeaHawk which was actually a fighter aircraft like the Rufe in addition to a two-seat gunnery spotter and transport for an injured man in a litter. Spotter seaplane aircraft on U.S. Navy cruisers and battleships were in service until 1949. By World War II, seaplane tenders were no longer considered as the main method to project air power at sea due to the lessened flight performance of their seaplanes over land and carrier-based planes. Carriers could operate conventional aircraft that could fly farther, faster, and carry more weapons, all while boasting greater performance. However, seaplane tenders in conjunction with PBY Catalina patrol bombers could range farther across the oceans than short-range carrier planes as the "eyes of the fleet" and rescued thousands of men stranded in the water who would have perished otherwise. As the end of the war neared, early helicopters were taking over many of the roles of seaplanes but at a marked loss in speed, range and flexibility that has not been regained to the present day. In the 1950s the aerodynamic limitations of seaplanes had finally been overcome; several seaplane designs were superior in performance to their land-based counterparts; the P-6M Seamaster patrol bomber and R3Y Tradewind "Flying LST" transport planes flew faster than the B-52 and the C-130; but in a power struggle with the ruling aircraft carrier bureaucracy were cancelled despite that their use in conjunction with special seaplane tenders would be more tactically and cost effective than large, vulnerable aircraft carriers operating shorter ranged and lesser payload aircraft. Post-war developments Many modern warships have helicopter landing capability and helicopter assault ships represent a new form of amphibious assault carrier. History and milestones Though aircraft carriers are given their definition with respect to fixed-wing aircraft, the first known instance of using a ship for airborne operations occurred in 1806, when the British Royal Navy's Lord Thomas Cochrane launched kites from the 32-gun frigate HMS Pallas in order to drop propaganda leaflets on the French territory. Balloon carriers
Seaplane carriers
Genesis of the flat-deck carrier
Inter-war years
Second World War Aircraft carriers played a significant role in World War II. With seven aircraft carriers afloat, the British Royal Navy had a considerable numerical advantage at the start of the war as neither the Germans nor the Italians had carriers of their own. However, the vulnerability of carriers compared to traditional battleships when forced into a gun-range encounter was quickly illustrated by the sinking of HMS ''Glorious'' by German battlecruisers during the Norwegian campaign in 1940. This apparent weakness to battleships was turned on its head in November 1940 when HMS ''Illustrious'' launched a long-range strike on the Italian fleet at Taranto. This operation incapacitated three of the six battleships in the harbour at a cost of two of the 21 attacking Fairey Swordfish torpedo bombers. Carriers also played a major part in reinforcing Malta, both by transporting planes and by defending convoys sent to supply the besieged island. The use of carriers prevented the Italian Navy and land-based German aircraft from dominating the Mediterranean theatre. In the Atlantic, aircraft from HMS Ark Royal and HMS ''Victorious'' were responsible for slowing ''Bismarck'' during May 1941. Later in the war, escort carriers proved their worth guarding convoys crossing the Atlantic and Arctic oceans. Many of the major battles in the Pacific involved aircraft carriers. Japan started the war with ten aircraft carriers, the largest and most modern carrier fleet in the world at that time. There were six American aircraft carriers at the beginning of the hostilities, although only three of them were operating in the Pacific. Drawing on the 1939 Japanese development of low-depth runs for aerial torpedoes and the 1940 British aerial attack on the Italian fleet at Taranto, the 1941 Japanese surprise attack on Pearl Harbor was a clear illustration of the power projection capability afforded by a large force of modern carriers. Concentrating six flattops in a single striking unit marked a turning point in naval history, as no other nation had fielded anything comparable. (Though Germany and Italy began construction of carriers, neither were completed. Of the two, Germany's Graf Zeppelin had the greater potential.) Meanwhile, the Japanese began their advance through Southeast Asia and the sinking of ''Prince of Wales'' and ''Repulse'' by Japanese land-based aircraft drove home the need for this ship class for fleet defence from aerial attack. In April 1942, the Japanese fast carrier strike force ranged into the Indian Ocean and sank shipping, including the damaged and undefended carrier HMS ''Hermes''. Smaller Allied fleets with inadequate aerial protection were forced to retreat or be destroyed. In the Coral Sea, US and Japanese fleets traded aircraft strikes in the first battle where neither side's ships sighted the other. At the Battle of Midway four Japanese carriers were sunk by planes from three American carriers, and the battle is considered the turning point of the war in the Pacific. Subsequently the US was able to build up large numbers of aircraft aboard a mixture of fleet, light and (newly commissioned) escort carriers, primarily with the introduction of the Essex class in 1943. These ships, around which were built the fast carrier task forces of the Third and Fifth Fleets, played a major part in winning the Pacific war. The eclipse of the battleship as the primary component of a fleet was clearly illustrated by the sinking of the largest battleship ever built, ''Yamato'', by carrier-borne aircraft in 1945. Japan also built the largest aircraft carrier of the war, ''Shinano'', which, like Yamato, was named after a Japanese province. Wartime innovations
Light Aircraft Carriers The loss of three major carriers in quick succession in the Pacific led the US Navy to develop the light carrier (CVL) from light cruiser hulls that had already been laid down. These were intended to add fighter squadrons to a task force, and were used in the US Navy only during World War II. The actual U.S. Navy classification was small aircraft carrier (CVL), not light. Prior to July 1943, they were just classified as aircraft carriers (CV). The British Royal Navy made a similar design which served both them and Commonwealth countries after World War II. One of these carriers, India's INS ''Viraat'', formerly HMS ''Hermes'', is still being used. Escort Carriers and Merchant Aircraft Carriers To protect Atlantic convoys, the British developed what they called Merchant Aircraft Carriers, which were merchant ships equipped with a flat deck for half a dozen aircraft. These operated with civilian crews, under merchant colors, and carried their normal cargo besides providing air support for the convoy. As there was no lift or hangar, aircraft maintenance was limited and the aircraft spent the entire trip sitting on the deck. These served as stop-gap until dedicated escort carriers could be built in the US (US classification CVE). About a third of the size of a fleet carrier, it carried about two dozen aircraft for anti-submarine duties. Over one hundred were built or converted from merchantmen. Escort carriers were built in the US from two basic hull designs: one from a merchant ship, and the other from a slightly larger, slightly faster tanker. Besides defending convoys, these were used to transport aircraft across the ocean. Nevertheless, some participated in the battles to liberate the Philippines, notably the battle off Samar in which six escort carriers and their escorting destroyers briefly took on five Japanese battleships and bluffed them into retreating. Catapult Aircraft Merchantmen As an emergency stop-gap before sufficient merchant aircraft carriers became available, the British provided air cover for convoys using Catapult aircraft merchantman (CAM ships) and merchant aircraft carriers. CAM ships were merchant vessels equipped with an aircraft, usually a battle-weary Hawker Hurricane, launched by a catapult. Once launched, the aircraft could not land back on the deck and had to ditch in the sea if it was not within range of land. Over two years, fewer than 10 launches were ever made, yet these flights did have some success: 6 bombers for the loss of a single pilot. Post-war developments
Angled decks During the Second World War, aircraft would land on the flight deck parallel to the long axis of the ship's hull. Aircraft which had already landed would be parked on the deck at the bow end of the flight deck. A crash barrier was raised behind them to stop any landing aircraft which overshot the landing area because its landing hook missed the arrestor cables. If this happened, it would often cause serious damage or injury and even, if the crash barrier was not strong enough, destruction of parked aircraft. An important development of the early 1950s was the British invention of the angled deck, where the runway was canted at an angle of a few degrees across the ship. If an aircraft misses the arrestor cables, the pilot only needs to increase engine power to maximum to get airborne again and will not hit the parked aircraft because the angled deck points out over the sea. The USS ''John C. Stennis'' is an example of an aircraft carrier that utilizes the concept of an angled landing deck. Steam catapults The modern steam-powered catapult, powered by steam from the ship's boilers or reactors, was invented by Commander C.C. Mitchell RNVR. It was widely adopted following trials on HMS ''Perseus'' between 1950 and 1952 which showed it to be more powerful and reliable than the compressed air catapults which had been introduced in the 1930s. Landing systems Another British invention was the glide-slope indicator (also known as a "meatball"). This was a gyroscopically-controlled lamp (which used a Fresnel lens) on the port side of the deck which could be seen by the aviator who was about to land, indicating to him whether he was too high or too low in relation to the desired glidepath. It also took into account the effect of the waves on the flight deck. The device became a necessity as the landing speed of aircraft increased. Nuclear age The US Navy prematurely attempted to become a strategic nuclear force with the project to build ''United States'', termed CVA, with the "A" signifying "atomic". This ship would have carried twin-propeller bombers, each of which could carry an atomic bomb. The project was cancelled under pressure from the newly-created United States Air Force, and the letter "A" was re-cycled to mean "attack." But this only delayed the growth of carriers. Nuclear weapons would put to sea despite Air Force objections in 1955 aboard USS ''Forrestal'', and by the end of the fifties the Navy had a series of nuclear-armed attack aircraft. The US Navy also built aircraft carriers powered by nuclear reactors. USS ''Enterprise'' was the first aircraft carrier to be powered in this way and subsequent supercarriers took advantage of this technology to increase their endurance. The only other nation to have followed the US lead is France with ''Charles de Gaulle''. Helicopters The post-war years also saw the development of the helicopter with different capabilities to a fighter aircraft. Whereas fixed-wing aircraft are suited to air-to-air combat and air-to-surface attack, helicopters are used to transport equipment and personnel and can be used in an anti-submarine warfare role with dipped sonar and missiles. In the late 1950s and early 1960s, the UK converted some of its old carriers into Commando Carriers, sea-going helicopter airfields like HMS ''Bulwark''. To militate against the expensive connotations of the term "aircraft carrier", the new ''Invincible'' class carriers were originally designated "through deck cruisers" and were initially helicopter only craft to operate as escort carriers. The arrival of the Sea Harrier meant they could carry fixed wing aircraft despite their short flight deck. UN carrier operations in the Korean War The United Nations command began carrier operations against the North Korean Army on July 3, 1950 in response to the invasion of South Korea. Task Force 77 consisted at that time of the carriers ''Valley Forge'' and HMS ''Triumph''. Before the armistice of July 27, 1953, 12 U.S. carriers served 27 tours in the Sea of Japan as part of the Task Force 77. A second carrier unit, Task Force 95, served as a blockade force in the Yellow Sea off the west coast of North Korea. The task force consisted of a Commonwealth light carrier (''Triumph'', ''Theseus'', ''Glory'', ''Ocean'', and HMAS ''Sydney'') and usually a U.S. escort carrier (''Badoeng Strait'', ''Bairoko'', ''Point Cruz'', ''Rendova'', and ''Sicily''). Over 301,000 carrier strikes were flown during the Korean War: 255,545 by the aircraft of Task Force 77; 25,400 by the Commonwealth aircraft of Task Force 95, and 20,375 by the escort carriers of Task Force 95. United States Navy and Marine Corps carrier-based combat losses were 541 aircraft. The Fleet Air Arm lost 86 aircraft in combat, and the Fleet Air Arm of Australia 15. U.S. carrier operations in Southeast Asia The United States Navy fought "the most protracted, bitter, and costly war" (René Francillon) in the history of naval aviation from August 2, 1964 to August 15, 1973 in the waters of the South China Sea. Operating from two deployment points (Yankee Station and Dixie Station), carrier aircraft supported combat operations in South Vietnam and conducted bombing operations in conjunction with the U.S. Air Force in North Vietnam under Operations Flaming Dart, Rolling Thunder, and Linebacker. 21 aircraft carriers (all operational attack carriers during the era except ''John F. Kennedy'') deployed to Task Force 77 of the U.S. Seventh Fleet, conducting 86 war cruises and operating 9,178 total days on the line in the Gulf of Tonkin. 530 aircraft were lost in combat and 329 more in operational accidents, causing the deaths of 377 naval aviators, with 64 others reported missing and 179 taken prisoner-of-war. 205 officers and men of the ship's complements of three carriers (''Forrestal'', ''Enterprise'', and ''Oriskany'') were killed in major shipboard fires. Falklands War During the Falklands War the United Kingdom was able to win a conflict 8,000 miles (13,000 km) from home in large part due to the use of the full size carrier HMS Hermes and the smaller HMS ''Invincible''. The Falklands showed the value of a VSTOL aircraft — the Hawker-Siddeley Harrier (the RN Sea Harrier and press-ganged RAF Harriers) in defending the fleet and assault force from shore based aircraft and for attacking the enemy. Helicopters from the carriers were used to deploy troops and pick up the wounded. Operations in the Gulf The US has also made use of carriers in the Persian Gulf, Afghanistan and to protect its interests in the Pacific. During the 2003 invasion of Iraq US aircraft carriers served as the primary base of US air power. Even without the ability to place significant numbers of aircraft in Middle Eastern airbases, the United States was capable of carrying out significant air attacks from carrier-based squadrons. Recently, US aircraft carriers, such as the USS Ronald Reagan provided air support for counter-insurgency operations in Iraq. Aircraft carriers today Aircraft carriers are generally the largest ships operated by navies; a Nimitz class carrier powered by two nuclear reactors and four steam turbines is 1092 feet (333 m) long and costs about $4.5 billion. The United States has the majority of aircraft carriers with a dozen in service, and its aircraft carriers are a cornerstone of American power projection capability. Nine countries maintain aircraft carriers: United States, United Kingdom, France, Russia, Italy, India, Spain, Brazil, and Thailand. In addition the People's Republic of China's People's Liberation Army Navy possesses the former Soviet aircraft carrier ''Varyag'', but most naval analysts believe that they have no intention to operate it, but instead are using Varyag to learn about carrier operations for future Chinese aircraft carriers. Canada, the People's Republic of China, Japan, Pakistan, Australia, Chile and Singapore also operate vessels capable of carrying and operating multiple helicopters. Aircraft carriers are generally accompanied by a number of other ships, to provide protection for the relatively unwieldy carrier, to carry supplies, and to provide additional offensive capabilities. This is often termed a battle group or carrier group, sometimes a carrier battle group. In the early 21st century, worldwide aircraft carriers are capable of carrying about 1250 aircraft. US carriers account for over 1000 of these; the second leading country, the United Kingdom fields around 66 aircraft. The United Kingdom and France are both undergoing a major expansion in carrier capability (with a common ship class), but the United States will still maintain a very large lead.
Future aircraft carriers Several nations which currently possess aircraft carriers are in the process of planning new classes to replace current ones. British Royal Navy The Royal Navy is currently planning two new larger STOVL aircraft carriers (as yet only known as CVF) to replace the three ''Invincible'' class carriers currently in service. These two ships are expected to be named HMS ''Queen Elizabeth'' and HMS ''Prince of Wales''. They will be able to operate about 50 aircraft and will have a displacement of around 60,000 tonnes. The two ships are due to enter service in 2012 and 2015 respectively. Their primary aircraft complement will be made up of F-35 Lightning IIs, and their ship's company will number around 1000. The two ships will be the largest warships ever built for the Royal Navy. Initially to be configured for STOVL operations, the carriers are to be adaptable to allow any type of future generation of aircraft to operate from them. Chinese Peoples Liberation Army Navy In June 2005, it was reported by boxun.com that the People's Republic of China would build a US$362 million aircraft carrier with a displacement of 78,000 tonnes, to be built by the enclosed Jiangnan Shipyard in Shanghai.The ship is suppose to carry around 70 4th generation jet aircraft (may carry 5th generation jet aircraft when available) The report was denied by Chinese defense official Zhang Guangqin. Previous talks to purchase an aircraft carrier from Russia and France have not borne fruit. On March 10, 2006, People's Liberation Army Lt. Gen. Wang Zhiyuan announced that the People's Republic of China will research and build an aircraft carrier to develop a CVBG in 3 to 5 years. Observers say the first carrier would be deployed to secure energy supply lines in the South China Sea. Fighters included on the carrier may include the J-10B and a modified SU-30MKK. French Marine Nationale
Indian Navy
Italian Marina Militare The construction of the conventional powered Marina Militare STOVL aircraft carrier ''Cavour'' began in 2001. It is being built by Fincantieri of Italy. After much delay, Cavour is expected to enter service in 2008 to complement the Marina Militare aircraft carrier ''Giuseppe Garibaldi''. A second aircraft carrier in the 25-30,000 tonne range is much desired by the Italian Navy, to replace the already decommissioned helicopter carrier ''Vittorio Veneto'', but for budgetary reasons all further development is on hold. It is provisionally called Alcide de Gasperi. Royal Australian Navy The Royal Australian Navy is currently investing in two Canberra class large amphibious ships, which will either be the French ''Mistral'' class or the Spanish ''Buque de Proyección Estratégica'' design. While the Navy has not considered operating fixed-wing aircraft from the ships, it has been suggested by commentators that they also operate aircraft such as the F-35B. Both to be in service by 2012. Russian Navy The Russian navy has one operational aircraft carrier, ''Admiral Kuznetsov''. Russia is currently developing a new aircraft carrier design. They are starting from scratch to make a modern model, with the newest available materials and electronics. Requirements would be for two aircraft carriers - one for the Russian Northern Fleet and one for the Russian Pacific Fleet. Construction is set to begin by 2010, and finish in around 6 years. The Ulyanovsk supercarrier design is being revised. Spanish Armada
US Navy
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