The Centerpiece of Modern Combat Fleets
Aircraft carrier is a warship equipped with a large open deck for the taking off and landing of warplanes and with facilities to carry, service, and arm them. It is an airfield at sea with many special features necessitated by limitations in size and the medium in which it operates.
To facilitate short takeoffs and landings, airspeeds over the deck are increased by turning the ship into the wind. Catapults flush with the flight deck assist in launching aircraft; for landing, aircraft are fitted with retractable hooks that engage transverse wires on the deck, braking them to a quick stop.
Aircraft carriers are amazing engineering marvels and like all other major inventions it took lot of pain and effort to bring them in their current form, but an important question to ponder here is that when and where this amazing quest started?
As early as November 1910, an American civilian pilot, Eugene Ely, flew a plane off a specially built platform on the deck of the U.S. cruiser Birmingham at Hampton Roads, Virginia.
On January 18, 1911, in San Francisco, Ely landed on a platform built on the quarterdeck of the battleship Pennsylvania, using wires attached to sandbags on the platform as arresting gear; he then took off from the same ship. It was a challenging task but Ely converted this challenge into an opportunity which enabled the world to land aircrafts on the naval ships.
Structure of Aircraft Carrier
The top of the carrier is the flight deck, where aircraft are launched and recovered. On the starboard side of this is the island, where the funnel, air-traffic control and the bridge are located.
As “runways at sea”, aircraft carriers have a flat-top flight deck, which launches and recovers aircraft. Aircraft launch forward, into the wind, and are recovered from astern. The flight deck is where the most notable differences between a carrier and a land runway is found, flight deck is smaller than a normal runway.
Shorter runway length of the deck requires that aircraft accelerate more quickly to gain lift. This either requires a thrust boost, a vertical component to its velocity, or a reduced take-off load (to lower mass).
Configurations Involved in Operating an Aircraft from Aircraft Carriers
Catapult assisted take-off but arrested recovery (CATOBAR): A steam or electric-powered catapult is connected to the aircraft, and is used to accelerate conventional aircraft to a safe flying speed. By the end of the catapult stroke, the aircraft is airborne and further propulsion is provided by its own engines. This is the most expensive method as it requires complex machinery to be installed under the flight deck, but allows for even heavily loaded aircraft to take off.
Short take-off but arrested recovery (STOBAR): Aircraft do not require catapult assistance for take off; instead on nearly all ships of this type an upwards vector is provided by a ski-jump at the forward end of the flight deck, often combined with thrust vectoring by the aircraft. Alternatively, by reducing the fuel and weapon load, an aircraft is able to reach faster speeds and generate more upwards lift and launch without a ski-jump or catapult.
Short take-off vertical-landing (STOVL): On aircraft carriers, non-catapult-assisted, fixed-wing short takeoffs are accomplished with the use of thrust vectoring, which may also be used in conjunction with a runway “ski-jump”.
Vertical take-off and landing (VTOL): Aircraft are specifically designed for the purpose of using very high degrees of thrust vectoring (e.g. if the thrust to weight-force ratio is greater than 1, it can take off vertically), but are usually slower than conventionally propelled aircraft.
Why Own an Aircraft Carrier?
The aircraft carrier’s diverse mission set has been used regularly in conflicts and crises throughout the world over the last 100 years. Diplomacy, power projection, quick crisis response force, land attack from the sea, sea base for helicopter and amphibious assault forces, Anti-Surface Warfare (ASUW), Defensive Counter Air (DCA), and Humanitarian Aid Disaster Relief (HADR) are just some of the missions the aircraft carrier can accomplish.
When a crisis occurs on or near a body of water, the aircraft carrier is unique in the speed at which it can arrive, and its independence once on station. Timely responses to emerging conflicts or disasters, even when the arriving force is small in scale, can greatly affect cost and outcome. In many cases, an aircraft carrier is the quickest, most credible military force available.
What are the Major Threats to the Aircraft Carrier and What Can Be Done to Protect It?
Anti-Ship Missiles: Many nations have immense anti-ship missile capability and boasts the widest inventory of ballistic and cruise missiles in the world. They contain an active radar and infrared imaging seeker for target determination in the terminal phase.
Drone Swarms: In the near term, the potential exists that capable adversaries will possess drone swarms able to perform a variety of anti-carrier tactics. These UAVs will be inexpensive and may be transported to the open sea through a variety of methods including submarines, surface ships, or from stealthy UAV ‘mother-ships’. The swarm of UAVs would work in concert, attacking soft targets on the carrier such as personnel, aircraft on the flight deck, ship sensors, and exposed ordnance.
In light of air threat system improvements, several nations are researching a wide range of future defensive capabilities. Deployable Lasers, Electromagnetic Rail Gun and Hypervelocity Projectiles, Surface-to-Air Missiles are few notable examples.
Scope for Future Developments
Research is going on to improve nuclear reactors which can provide more power to the carriers. This outsized power generation capacity will provide an opportunity to grow into new technologies that come up during their service life. With ample power to draw from, the ships could one day house directed energy weapons.
Electromagnetic Aircraft Launch System (EMALS) is an elaborate steam-powered launch system which can be used on the carriers, not only will the EMALS launch heavier planes, but it will carefully launch planes in order to reduce wear and tear. Additionally, the increased capacity of these launchers to make planes airborne will allow new plane designs in the future.
Advanced Weapons Elevators : New carriers will use electromagnetic fields to raise and lower platforms instead of cabling. This allows a simpler design to compartmentalize the different areas of the ship, which will help reduce maintenance and manning costs over the life of the ship. Also, new cargo elevators will replace cargo converters, which were labor intensive.
Aircraft Carriers are the titans of the sea by their diplomatic and tactical power, its mobility, its autonomy and the variety of its means, the aircraft carrier is often the centerpiece of modern combat fleets. Tactically or even strategically, it replaced the battleship in the role of flagship of a fleet. Every nation wants to own it and our country India also has INS Vikramaditya, a STOBAR carrier and an engineering marvel.
– An Article by Manish Kumar, 3rd Year Mechanical Engineering.