Flight deck configuration
Modem aircraft carriers have a flat-top deck, the flight deck that serves as a take-off and landing area for 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 о 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 the 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, some 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 utilise their hover capability to land vertically and so require no assistance in speed reduction upon landing.
The primary function of the angle deck landing area is to allow aircraft who miss the arresting wires, to become airborne again without the risk of hitting aircraft parked on the forward parts of the deck. The angle 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, engine exhausts 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.
A more recent configuration, used by the 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.
During the Second World War, aircraft would land on the flight deck
parallel to the long axis Я 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 1940s 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.
As now only nuclear powered carriers have boilers as part of their motive power system, the majority of aircraft carriers are now equipped with steam generating plant solely to power the catapults. USS Enterprise was the first aircraft carrier to be powered in this way and subsequent super carriers took advantage of this technology to increase their endurance.
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.
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 addi-
tional offensive capabilities.
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