aircraft carrier


Значение термина aircraft carrier в knolik


aircraft carrier - Aircraft Carrier
aircraft carrier - by Capt. Norman Macmillan, M.C., A.F.C.

This article deals with developments in the design of aircraft carriers since 1917, with their strategical and tactical deployment in war, and explains fully how carrier-borne aircraft are operated from the parent vessel. See also Fleet Air Arm

In the earliest days of naval flying, officer pilots of the Naval Wing, Royal Flying Corps, the forerunner of the Royal Naval Air Service, realized that their metier was air-cooperation with ships; and almost as soon as they had learned to fly, they sought means to use their aeroplanes from ships. Their experimentation took two lines: (1) development of seaplanes that could be flown from water, and hoisted outboard and inboard by parent ships called seaplane carriers; (2) flying land-planes from ships. It was the continuation of the second line of experimentation that brought about the aircraft carrier, a type of ship pioneered by the Royal Navy.

early history

In 1911 Lt. C. R. Samson (one of the first four naval pilots) designed and had built in Chatham dockyard a double trackway for aeroplanes. It was erected in H.M.S. Africa, and Samson took off from it in Dec., 1911. The platform, erected forward of the superstructure, could not be used for alighting. Airbags were therefore fitted to the undercarriages of early ship aeroplanes so that they could alight on the water alongside the parent ship. But this was unsatisfactory. It was realized that it was essential for the aeroplane to be able to alight on board a ship if it was to serve the real needs of the navy. Fit. Comdr. E. H. Dunning piloted the first plane to alight-on board the ship from which it was launched. On Aug. 2, 1917, he made a skilful landing in a Sopwith Pup on the forecastle launching deck of H.M.S. Furious while she was under way. Five days later, during a second attempt, the Pup rolled off the deck, fell into the sea, and Dunning was drowned. The Furious was then fitted with a landing deck aft. On July 19, 1918, aeroplanes flown from this ship destroyed a Zeppelin shed at Tondern. The Furious, originally designed as a cruiser (1916), underwent yet a third conversion. In 1925 she was commissioned as a flush-deck aircraft carrier. In her first eon-version she carried 8 aircraft (Pups and Short seaplanes); in her second she carried 16 aircraft (Sopwith Camels and IJ-Strutters); in her third conversion she carried 33 aircraft, and in this form continued in commission and served in the Second Great War.

H.M.S. Argus was the first aircraft carrier with a flush deck; and the first to embark (Oct. 19, 1918) a squadron of torpedo-carrying aeroplanes. Her complement was 20 aircraft.

The Furious and the Argus were the only real aircraft carriers (as distinct from parent ships) in commission during the First Great War. They were followed between the two Great Wars by the Eagle, Hermes, Courageous, Glorious, and Ark Royal (completed 1919, 1923, 1928, 1930, arid 1938, and carrying 21, 15, 48, 48, and 60 aircraft respectively). The speed of these aircraft carriers varied from the 20 knots of the Argus to the 31 knots of the Furious.

Aircraft carriers in Other Countries

The Royal Navy, having pioneered the aircraft carrier, was followed by other nations' fleets. Japan's first aircraft carrier, the Hosho, was converted in 1922, to be followed in 1927, 1928, and 1933 by the Akagi, Kaga, and Ryujo. In 1921 the U.S. Navy fleet-collier Jupiter was converted to an experimental aircraft carrier and rechristened the Langley; she had a flush flight deck, and carried 30 aircraft; her speed was 14.9 knots. The first U.S.N. Fleet aircraft carriers were the Lexington and the Saratoga, both converted from battle cruisers under the Washington Treaty. They were completed in 1927, had a speed of 33.35 knots, and carried 72 aircraft. The Ranger, launched 1933, was the first U.S.N. aircraft carrier to be so designed from the outset. The first R.N. aircraft carriers so designed were the Hermes and the Ark Royal.

When the Second Great War began, there were 23 aircraft carriers in service in the world: U.K., eight; U.S.A., seven; Japan, seven; France, one (the Beam, converted in 1927 to carry 36-40 aircraft, with a ship speed of 21.5 knots). The German Graf Zeppelin, launched in 1938, was never completed; she was designed to carry 40 aircraft, with a ship speed of 32 knots.

aircraft operation

Airfield runways are measured in yards, are seldom less than 800 and may be 3,000 or more yds. long. Aircraft carrier flight decks are measured in feet, are seldom more than 800 ft. in length, and, in the smaller classes of ships (escort and merchant aircraft carriers) may be about half that length. Aircraft flying from aircraft carriers must therefore become airborne during a relatively short run, the maximum length of which is arbitrarily fixed by the dimensions of the flight deck. Rapid acceleration is important, and engine reliability fundamental, for once the take-off run has begun it is seldom feasible to stop and try again.

Pre-determined Wind-speed

To overcome the runway handicap and enable the pilot to start his flight with assurance, it is necessary to establish artificial take-off conditions on the flight deck. Basically, this is achieved by creating a predetermined wind-speed over the deck, to suit the particular aircraft and the load it carries. Advantage is taken of the natural wind, and the aircraft carrier steams head into wind during all flying-off operations. In conditions of calm, fast carriers, with speeds of about 30 knots, can operate their aircraft by steaming at or near full speed. The slower carriers may not be able to get enough wind-speed over their decks in these conditions, and other means must be sought to enable their aircraft to take off. The wind-speed flowing over the flight deck gives the aircraft the equivalent of a running start. If, for example, an aircraft becomes fully airborne and controllable at 70 knots air speed, and is subject to a wind of 30 knots while stationary on the flight deck, it need only accelerate to 40 knots relative to the deck to obtain the necessary 70 knots relative to the air. So, when steaming into wind of sufficient strength, carriers can take advantage of the conditions to reduce speed and conserve the ship's fuel, consumption of which increases rapidly at or near maximum speed.

In aircraft powered with supercharged engines pilots can use the supercharger for the few seconds of take-off to obtain additional power for the period of acceleration from the standing start to the fully airborne condition and its succeeding initial climb. When absence of wind, or the shortness of the deck run, or the weight of the load carried by the aircraft, or any combination of these three conditions makes the ordinary take-off too hazardous, recourse may be had to accelerators.

accelerators

Accelerators are of two kinds, one external to and the other integral with the aircraft. The first kind is the catapult. In the earlier form of catapult the aeroplane to be launched was mounted on a trolley which ran along rails. The trolley was propelled by a ram operated by either compressed air or the gas pressure of a special cordite cartridge; the second method became the standard. For many years these catapults were used on aircraft carriers; they are part of the equipment of other types of warships that carry aircraft, e.g. battleships and cruisers; they were used in the catapult aircraft merchant ships that preceded the merchant aircraft carriers. At 2½G (gravity) acceleration these catapults launch landplanes and seaplanes from rest to flying speed (about 60 knots) in 30 feet.

These catapults obstructed the decks of aircraft carriers, and a later form placed the mechanism under the flight deck. A cable running within a slotted rail provided the means to apply power to the aircraft through a strop attached to the undercarriage. This unobstructive form of catapult applied the same accelerative force to a landplane taking off on its own undercarriage.

Rocket Assistets

Rocket assisters were later employed to provide additional power for take-off. Mounted below the wings, close to the fuselage, they are ignited electrically by the pilot during his take-off run, and give additional propulsion by jet reaction for four seconds, enough to complete the take-off run and start the aircraft on its initial climb. The number of rockets (i.e. the propulsive force) is varied according to the type of aircraft and the conditions of deck-length, wind-speed, and load.

landing-on

Landing on a ship's deck has always been regarded as more hazardous than taking-off, and much care has been devoted to improving this operation. Wind-speed of sufficient strength and a true fore-and-aft air-flow over the deck are essential. The ship must therefore steam into wind, irrespective of the course of other ships which may accompany the carrier. Mechanical means have been devised to arrest the aircraft when it alights on the deck, and four stages of R.N. arrester gear development can be distinguished. These are as follows:

(1) Cables laid transversely across the deck with filled sand-bags attached to either end; these cables, entangling in the undercarriage and tail-skid, helped to retard the aeroplane.

(2) Fore and aft cables, held a few inches above the deck by stanchions, to engage in special hooks carried on the fixed undercarriages of the aircraft. The hooks had non-return spring jaws to retain the cables. The purpose was to keep the aircraft on the deck once it landed, prevent it from swerving, and arrest its speed by friction between cable and hook. This gear was not a success.

(3) A period when no mechanical deck arrester gear was employed. Wheel brakes had then become common to all aircraft, and were used both to arrest the aircraft and to control it direction-ally during the landing-on.

(4) Transverse arrester cables controlled by hydraulic braking mechanism below the flight deck. The number of arrester cables varies in different ships, but four is the minimum. For take-off conditions the cables lie flat on the deck; for landing-on they are raised to a suitable height above the flight deck by hydraulic rams, two to each cable. The engaging mechanism on the aircraft is a landing hook, carried beneath the after part of the fuselage and lowered by the pilot when required. The pilot approaches in a curving flight to keep the deck in view, straightening into wind and deck just above and behind the stern. The relative correctness of his approach is signalled to the pilot visually by means of two bats, of table-tennis shape, handled by the deck flying control officer (the " batsman "). It is often easier to judge an approach from the deck than from the aircraft, and a good "batsman" gives valuable guidance to the pilot.

When the hook engages a cable, the aircraft is brought rapidly to a standstill. Although comparatively smooth, the braking is powerful, and the air crew must brace themselves to resist the inertia forces affecting them during the landing. This is the standard method of deck landing in the R.N. and U.S.N.

In the earlier period of deck landing, nets and palisades were erected along the sides of the flight deck to prevent aircraft from falling overboard; these are no longer used, but transverse crash barriers are fitted in many carriers to safeguard aircraft parked on the forward part of the flight deck from.collision with aircraft failing to land-on or takeoff, and to prevent aircraft failing to hook-on from running over the bow. Wind brakes are sometimes fitted to give protection to aircraft parked on the flight deck.

ship development

Before the Second Great War almost all aircraft carriers were of different design, although some sister ships existed, notably the Courageous and Glorious, and the Saratoga and Lexington. The first aircraft carriers to be laid down (1937) for the R.N. as a class were the Illustrious, Victorious, Formidable. and Indomitable. These ships, like their predecessors, were fleet carriers - ships of 23,000 tons, capable of over 30 knots, carrying 16 4.5-in. dual purpose guns, and considerable deck and side armour to take knocks in addition to giving them. To compensate for their heavier armour they had one hangar for aircraft instead of the two superimposed hangars of the Ark Royal. Such ships arc costly - the Ark Royal cost £3,500,000 - but what is more important in war, they take some years to build. The Second Great War provided the first real experience of aircraft carriers in active service, and it became apparent that a sufficient number of units could not be provided in the large fleet carrier class to deal with the manifold duties of the air component of modern marine power. As a result, four distinct classes of aircraft carrier emerged. These were: (1) the fleet carrier; (2) the light fleet carrier; (3) the escort carrier; (4) the merchant aircraft carrier. The M.A.C.s were solely British. After three years' experience of war the U.S.N. laid down another class, a heavy fleet carrier with a displacement of over 45,000 tons, designed to carry larger types of aircraft.

Variations in British and American carrier design in armament, ship speed, armour, equipment, and the exact number of aircraft carried per ship produce additional sub-divisions among the carriers in each class; but it can be assumed that M.A.C.s carry one flight of aircraft; E.C.s two squadrons; L.F.C.s two to three squadrons; and F.C.s three to six squadrons.

Certain features are common to all aircraft carriers. Their superstructure is carried on the starboard side of the ship, and in the later ships is built out to offer the least restriction to the width of the flight deck, while remote control, applied whenever possible, is used to keep the dimensions of the superstructure to the minimum. Radio telephony and wireless telegraphy are used for communication between aircraft and carrier, ship and ship, and ship and shore. Direction-finding radio is used to give aircraft homing bearings on the ship. In most ships radio beacons enable pilots and aircraft wireless operators to determine the approximate directional position of the carrier. All the naval carriers are equipped with radar, which, as on land, enables the approach of enemy aircraft to be detected, so that counter measures can be taken for the defence of the carrier or fleet against air attack; the same means can be employed to detect enemy ships and organize an aircraft strike against them.

In addition to the captain, who is responsible for the whole ship, and the commander (executive), who is responsible to the captain for the ship's affairs, an aircraft carrier has a commander (flying), who is responsible for the aircraft side of the ship's activities, and an air staff officer who is responsible for the organization of the air operations detail. There are briefing and intelligence rooms for the air crews; an operations room for the control of all operational air activities; readiness rooms for air crews; chart room and chart store (charts are greatly multiplied, for every aircraft must be supplied with charts, and not only the ship, as in other categories of naval craft); photographic section and meteorological office.

On the air operational side an aircraft carrier has to be just as fully equipped as any shore operational air station.

Ship's Complement

The complement of an aircraft carrier is large, for in addition to the ship's company there are the air crews, aircraft mechanics, and the aircraft handlers who are the flight-deck crews. In the larger carriers the officer complement is from 50 to 100 per cent greater than in battleships and cruisers.. Embodied in the ship's company and equipment are to be found the usual components of a big ship - chaplain, schoolmaster, ship's stores, workshops, blacksmith, carpenter, paintshop, surgeon, operating theatre, and sick-bay; engineers for the main.engines, the hydraulic machinery, compressors, electrical generating plant, refrigerating plant, stokers (who are boilermen in oil-fired ships), electricians; galleys (electrified and very modern with monel metal fittings and electric hot cupboards); and canteen with, in some ships, a cafeteria. The hangar has a secondary use as a cinema. Lifts convey the aircraft from hangar to deck and vice versa. The lift well provides additional stowage space. M.A.C. grain ships have a lift; M.A.C. tankers have no lift, and their aircraft remain on deck throughout.

The lighter classes of carrier are constructed on merchant ship lines. Their engine-rooms are laid out as in the Merchant Navy, and are properly called machinery space. Naval carriers, like other large warships, contain a damage control room, a centralised action station coordinating the safety measures in a crippled ship.

Since full administrative and operational control over the Naval Air Arm was returned to the Board of Admiralty in 1938, all the personnel of the Air Branch have belonged exclusively to the Royal Navy. All the ships' companies are also R.N., except in the merchant aircraft carriers, wherein the ships' crews are Merchant Navy, and in the escort carriers, wherein the engineers are Merchant Navy incorporated within the Royal Naval Reserve.

carrier strategy and tactics

Aircraft carriers are not now, as formerly, concerned only with safeguarding sea communications, but must also play their part in combined operations to give cover to the army before and after a landing, spot for ship's guns providing such cover, undertake visual and photographic reconnaissance for the army and the covering ships, and provide mobile fire power through their aircraft with bomb, rocket fire, cannon-gun, and machine-gun. Such actions, in cooperation with the army, or when deployed against enemy land targets in task force duties, can be maintained at high pressure only for relatively brief periods because of the supply position in aircraft, petrol, bombs, and other material, and must be prepared for in advance. In this respect the aircraft carrier operation differs from that of a land-based air force, such as a Bomber Command, whose function is to maintain continuous operations. But aircraft carriers can operate for long periods at low pressure activity. Then- use thus falls into a strategic category which offers the elements of mobility of base, power of concentration of effort, surprise, and capacity of manoeuvre to avoid counter-attack.

The element of surprise is increased by the ability of the aircraft to operate from carriers at night, an air operation carried out in R.X. carriers either as practice or in exercises during the decade preceding the outbreak of the Second Great War.

The several types of aircraft carrier, with their varying speeds and ranges of action, different qualities of armour and ship's armament, and their capacity to carry the appropriate types of aircraft for specific duties, gave navies a new striking force which did not diminish but augmented their power in fleet actions, and enabled them not only to control the seas, but to dominate the once-feared coastal batteries and carry naval fire-power deep into enemy land territory.

Following the defeat of the Japanese naval elements in the battles of the Coral Sea, Midway, and the Philippines, and the continuous war of attrition in the Pacific, aircraft carrier supremacy passed in 1944-45 almost exclusively into the hands of the U.S. Navy and the Royal Navy, and for several years at least this predominance in naval air strength should remain unrivalled.

Рядом со словом aircraft carrier в knolik


aircraftВ начало
буква ""
буквосочетание ""
aircraft constructors, society of british

Статья про aircraft carrier была прочитана 642 раз

Our friends, knolik encyclopaedia knolik.com