Fu­ture Air­craft Car­ri­ers

It is an im­por­tant day for our na­tion. It is a golden day in In­dian Navy s his­tory. For me, it is a mat­ter of pride and hap­pi­ness that INS Vikra­ma­ditya is join­ing the Navy.

SP's NavalForces - - FRONT PAGE - LT GEN­ERAL NARESH CHAND (RETD)

It is a his­toric step. Prime Min­is­ter Naren­dra Modi while ded­i­cat­ing

INS Vikra­ma­ditya to the Na­tion, June 14, 2014.

An Air­craft Car­rier is a float­ing air­field and has all the com­po­nents which are re­quired to store, main­tain, fuel, arm, take off and land a fighter air­craft. Other aerial plat­forms like Air­borne early Warn­ing Air­craft e-2D Ad­vanced Hawk­eye, he­li­copters, UAVs and ro­tary un­manned aerial ve­hi­cles can also op­er­ate from a suit­ably de­signed air­craft car­rier. An air­craft car­rier en­ables a naval force to project its power glob­ally. Ad­mi­ral sir Mark stan­hope, former first sea Lord and chief of naval staff of the royal navy, has said that, Ò to put it sim­ply, coun­tries that as­pire to strate­gic in­ter­na­tional in­flu­ence have air­craft car­ri­ers Ó. fixed wing air­craft flew in 1903 and the first flight from the deck of a Us naval cruiser took place in 1910. this was fol­lowed by the de­vel­op­ment of sea­planes and sea­plane ten­der sup­port ships. the first de­signed air­craft car­rier was by UK which be­gan work on HMs Her­mes in 1918 and which was com­mis­sioned in 1924. Ja­pan be­gan work on Hōshō first pur­pose-built air­craft car­rier in 1918 and com­mis­sioned it in De­cem­ber 1922. How­ever they are costly to build, op­er­ate and main­tain thus only a hand­ful of coun­tries have air­craft car­ri­ers or some ver­sion of

it.An air­craft has to be heav­ily de­fended be­ing a vul­ner­a­ble strate­gic as­set with part of the naval air fleet on board. thus it is es­corted and de­fended by de­stroy­ers, light cruisers and other pow­er­ful fast bat­tle ships and has its own air de­fence which makes it strike the en­emy in the most un­likely of places.

Air­craft car­ri­ers in the Sec­ond World War

navies of Us, UK and Ja­pan had the max­i­mum air­craft car­ri­ers dur­ing the sec­ond World War. each car­rier of that pe­riod had over thou­sand sailors and up­wards of 30 air­craft. The US Navy fielded 36 car­ri­ers, the royal navy 24, the french navy had one ob­so­lete car­rier and the im­pe­rial Ja­panese navy about 23. the Us navy used most of their car­rier against the very pow­er­ful Ja­panese Navy in the Pa­cific that was ar­guably the most ca­pa­ble car­rier force at the be­gin­ning of the war. the Al­lies lost 9 air­craft car­ri­ers dur­ing the war.

Size of an air­craft car­rier

The fighter air­craft, in­ter­cep­tors and sup­port air­craft are the main ar­ma­ment of a car­rier. to put across sim­ply, big­ger the ship, big­ger will be the hangar and flight deck which ac­com­mo­dates the air wing. Ac­tual there is no di­rect re­la­tion­ship be­tween the size of the car­rier and the num­ber of air­craft it can carry. the chi­nese navy's air­craft car­rier Liaon­ing dis­places about six­ty­five thou­sand tons and car­ries twenty-six fixed-wing air­craft and twenty-four he­li­copters. Uss Ge­orge Wash­ing­ton, dis­places a lit­tle more than one hun­dred thou­sand tons but can op­er­ate some eighty-five to ninety air­craft. Us car­ri­ers have steam cat­a­pults which can launch heav­ier air­craft as com­pared to the ski jump. Heav­ier air­craft im­plies more fuel ca­pac­ity and weapons thus im­prov­ing their lethal­ity and range. Larger car­ri­ers also al­low the flex­i­bil­ity of a va­ri­ety of mix of the air­craft, de­pend­ing on the mis­sion. On the other hand ins Vikra­ma­ditya has a dis­place­ment of 45,400 tons when loaded and can carry a max­i­mum of 36 all type of air­crafts. How­ever it is ca­pa­ble of car­ry­ing out the role for which it has been ac­quired. thus size of an air­craft car­rier should be tai­lor made for the role as a larger car­rier es­ca­lates the cost as­tro­nom­i­cally.

Launch­ing Sys­tems

Deck is a mo­bile air­field, length of which will de­pend upon the dis­tance re­quired for the air­craft to take off. A longer deck means a big­ger air­craft car­rier which has its own prob­lems. thus there is al­ways an en­deav­our to re­duce the length of the deck. this can be done by cat­a­pult As­sisted take- Off (Ca To) or chang­ing the di­rec­tion of the thrust of the air­craft as in Ver­ti­cal and/or short take-Off (V/ Sto). De­tails with pro and cons are given be­low:

● Cat­a­pult As­sisted Take-Off But Ar­rested Re­cov­ery (CATOBAR). A steam-pow­ered cat­a­pult pro­vides the air­craft safe fly­ing speed af­ter which it uses its own power to fly. US em­ploys this sys­tem. it is re­ported that china is try­ing to de­velop this sys­tem. this sys­tem is very costly as it re­quires com­plex ma­chin­ery.

● Short take-off but ar­rested re­cov­ery (STOBAR). this depends on in­creas­ing the net lift on the air­craft. in this sys­tem the up­ward thrust is pro­vided by a ski-jump lo­cated at the for­ward end of the flight deck. This is of­ten com­bined with thrust vec­tor­ing by the air­craft.

● Short take-off ver­ti­cal-land­ing (STOVL). STOVL on fixed wing air­craft is achieved by the use of thrust vec­tor­ing, which may also be com­bined with a ski-jump. sea Har­rier short take-off and ver­ti­cal land­ing/ver­ti­cal take-off and land­ing jet fighter, is an an ex­am­ple which In­dia has em­ployed for many decades. the sea Har­ri­ers op­er­ated from ins Vi­raat for the last time on March 6, 2016. Use of STOVL en­ables air­craft to carry a larger pay­load as com­pared to V tOL but still re­quir­ing a short run­way. sea Har­ri­ers is tech­ni­cally a Vt OL air­craft but are op­er­ated as Stovl air­craft for car­ry­ing ad­di­tional fuel and ar­ma­ment. f-35B Light­ning ii has VTOL ca­pa­bil­ity in test flights but is op­er­a­tionally stOVL.

● Ver­ti­cal take-off and land­ing ( VtOL): Air­craft are specif­i­cally de­signed for the pur­pose of us­ing very high de­grees of thrust vec­tor­ing. there are many ex­am­ples of these in­clud­ing sea Har­rier, f-35B and Bell Boe­ing V-22 Osprey (tilt -ro­tor). Al­most all car­ri­ers have ar­rested-re­cov­ery sys­tems (Ar, e.g. Ca To Bar or Sto Bar) to re­cover the air­craft. VtOL ca­pa­ble air­craft or he­li­copters can land with­out any as­sis­tance as they do not have to de­cel­er­ate while land­ing.

Propul­sion Sys­tems

Nu­clear. nu­clear marine propul­sion can be pro­vided to sur­face ships and sub­marines where the role en­vis­aged is to pro­vide al­most un­lim­ited and un­in­ter­rupted global reach with­out pause for re­fu­el­ing. it is a highly tech­ni­cal field with few na­tions hav­ing nu­clear propul­sion tech­nol­ogy and is also costly. to ex­plain in sim­ple terms the nu­clear plant pro­vides heat for con­vert­ing wa­ter into stream which pow­ers the steam tur­bines and the turbo gen­er­a­tors. this power is then used for propul­sion through gear boxes. the plant is di­vided into two parts , one for the port and the other for the star­board side to cater for fail­ure of one side. sea wa­ter is pumped, de­sali­nated and pro­vided to gen­er­ate steam. the heat is trans­ferred through wa­ter to steam gen­er­a­tors which have a tem­per­a­ture of about 250 to 300¡c. As wa­ter va­por­izes at 100¡c at nor­mal pres- sure, the sys­tem is pres­sur­ized to in­crease the boil­ing tem­per­a­ture of the wa­ter. this wa­ter is nor­mally called feed wa­ter. Us, rus­sian and Bri­tish navies gen­er­ally use steam tur­bine propul­sion while france and china use tur­bines to gen­er­ate elec­tric­ity. the num­ber of re­ac­tors vary de­pend­ing upon the role like most of the Us air­craft car­ri­ers have two re­ac­tors but Uss en­ter­prise has eight. charles de Gaulle of the french navy also has two pres­sure wa­ter re­ac­tors. nimitz class of Us air­craft car­ri­ers like Uss Ge­orge H.W. Bush has two Gen­eral elec­tric pres­surised wa­ter re­ac­tors driv­ing four tur­bines of 260,000hp (194MW) and four shafts. As a re­sult of the use of nu­clear power, these ships are ca­pa­ble of op­er­at­ing for over 20 years with­out re­fu­el­ing and the an­tic­i­pated ser­vice life of over 50 years. they have a dis­place­ment of 101,600–106,300 tonnes.

Con­ven­tional. tur­bines are nor­mally used for propul­sion and can be steam or gas. Air­craft car­rier s‹ o Paulo of Brazil navy car­rier is pow­ered by four Par­sons steam tur­bines pro­duc­ing 126,000shp. Six In­dret boil­ers pro­vide steam for the main propul­sion tur­bines. On-board power is gen­er­ated by two turbo al­ter­na­tors and six 2,000kW diesel gen­er­a­tors. it has a dis­place­ment of 32,000tonnes at full load. cavour Air­craft car­rier of the ital­ian navy is a com­bi­na­tion of gas tur­bine and gas (cOGAG) propul­sion. the four LM2500 gas tur­bines, de­vel­op­ing 22,000kW each, are man­u­fac­tured by fia tAvio of turin un­der a li­cence agree­ment from Gen­eral elec­tric (Us). Air­craft car­rier Giuseppe Garibaldi of the ital­ian navy is pow­ered by four Fiat-g. e LM 2500 gas tur­bines pro­vid­ing 82,000 hp and 6 × Diesel gen­er­a­tors (9.360 KW) with a dis­place­ment is 13,850tonnes (loaded). ins Vikramditya has 8 turbo-pres­surised boil­ers, 4 shafts, 4 geared steam tur­bines gen­er­at­ing 180,000 horse­power (134,226 kW). It has a dis­place­ment of 45,400 tonnes( loaded).

Fu­ture Air­craft Car­ri­ers

the Us navy cur­rently has the worldÕs largest fleet of nu­clear pow­ered air­craft car­ri­ers, com­prised of the nimitz class and the up­com­ing Ger­ald r. ford class su­per car­ri­ers. Apart from the size of their air­craft car­rier fleet, US also leads in air­craft car­rier tech­nol­ogy, thus the cur­rent/ fu­ture role, de­sign

Tech­nol­ogy and cost comes in the way of late starters like In­dia and China who want to de­sign and con­struct their own air­craft car­ri­ers. Air­craft car­rier avi­a­tion re­ally does not de­pend that much on the car­rier but the com­plex sys­tem of avi­a­tion op­er­a­tions which fi­nally project power. US Navy has re­ally a high stan­dard in this field thus worth em­u­lat­ing.

and tech­nol­ogy sets the trend for na­tions to em­u­late for con­struct­ing their own air­craft car­ri­ers. Many naval an­a­lysts in the Us are car­ry­ing out a re­view of the em­ploy­a­bil­ity of air­craft car­ri­ers in view of the threat of longer-range, pre­ci­sion-guided anti-ship mis­siles and next-gen­er­a­tion of hy­per­sonic at­tack weapons. in ad­di­tion to the mis­sile threat, the heavy cost fac­tor, threat, role and mid air re­fu­el­ing pro­vid­ing ex­tended ranges to fighter air­craft, are also fac­tors which lever­age a look at the air­craft car­ri­erÕs de­sign and sur­viv­abil­ity. it is likely that the fu­ture car­ri­ers will be equipped with greater high – tech sen­sors, im­proved ship de­fences, greater speed and ma­neu­ver­abil­ity to avoid en­emy fire and the deck de­signed to take on more num­ber of UAVs. the size could be smaller for bet­ter ma­neu­ver­abil­ity with on board UAVs, ex­tended range pre­ci­sion weapons and anti mis­sile de­fences. such car­ri­ers will be able to de­liver car­rier-based un­manned ca­pa­bil­ity to the fleet. Keep­ing these fac­tors in view, the ford class car­ri­ers have the flex­i­bil­ity of de­sign to adapt to the fu­ture ex­tremely high-threat en­vi­ron­ments. they should also a higher sor­tie gen­er­a­tion rate and au­toma­tion to re­duce the man­power. these threats could be from the chi­nese and rus­sian navies. chi­nese-built Df-21D mis­sile is spe­cially de­signed as a car­rier-killer which can de­stroy tar­gets at more than 1440 km thus pre­vent­ing air­craft car­ri­ers to op­er­ate close to the coast. the un­manned MQ-25 stingray is planned as a su­per Hor­net-sized car­rier-Based Aerial-re­fu­el­ing sys­tem which will in­crease the strike range of car­rier based fighter air­craft. It will be also be to pro­vide lim­ited isr and re­lay com­mu­ni­ca­tion and have a smaller radar sig­na­ture as com­pared ex­ist­ing manned re­fu­el­ing air­craft. inputs have been re­quested from Boe­ing, Gen­eral Atomics, Lock­heed Martin and northrop Grum­man and rfP is likely to be is­sued in 2017.

Air­craft car­ri­ers are al­ways op­er­ate in car­rier groups and are well with de­fended armed cruisers and de­stroy­ers. tech­nolo­gies of these ships in­clud­ing sen­sors and weapons will also have to keep with the fu­ture threat.

Launch­ing Sys­tem

elec­tro­mag­netic Air­craft Launch sys­tem (eMALs). is un­der de­vel­op­ment by Gen­eral Atomics for the Us navyÕs lat­est air­craft car­ri­ers, con­tract for which was given in 1999. the eMALs sys­tem is a multi-megawatt elec­tric power sys­tem in­volv­ing gen­er­a­tors, en­ergy stor­age, power con­ver­sion, a 100,000 hp elec­tric mo­tor, and an ad­vanced tech­nol­ogy closed loop con­trol sys­tem with built in per­for­mance mon­i­tor­ing. it is planned to re­place the cur­rent steam cat­a­pult be­ing used on all Us air­craft car­ri­ers. the Ger­ald R. Ford is des­ig­nated to be the first car­rier to use eMALs. the ad­van­tages of eMAL are re­duc­tion of man­ning work­load, ther­mal sig­na­ture, top­side weight and in­stalled vol­ume. it will also in­crease the launch ca­pa­bil­ity and will also be able to launch UAVs.

Weapon Sys­tems

Elec­tro Mag­netic (EM) Rail­gun. the eM rail­gun uses high-power eM en­ergy in­stead of ex­plo­sive chem­i­cal pro­pel­lants to fire a pro­jec­tile far­ther and faster than any cur­rent gun. When fully weaponized, a rail­gun will de­liver hy­per­ve­loc­ity pro­jec­tiles on tar­gets, at ranges far ex­ceed­ing any of the cur­rent naval guns. it will be able to ef­fec­tively in­ter­cept air threats, par­tic­u­larly anti-ship cruise mis­siles.

Naval In­te­grated Fire Con­trol Ð Counter Air sys­tem (NIF-CA). Us navy is de­vel­op­ing ship-based de­fen­sive weapons, elec­tronic war­fare sys­tems, lasers and tech­nolo­gies able to iden­tify and de­stroy ap­proach­ing anti-ship cruise mis­sile from ranges be­yond the hori­zon. ex­am­ple of this is cur­rently de­ployed nifc-cA which com­bines ship-based radar and fire con­trol sys­tems with an aerial sen­sor and dualmode SM-6 mis­sile, to track and de­stroy ap­proach­ing threats from over -the-hori­zon.

Laser Weapons. Laser weapon sys­tems (LaWs) are highly ac­cu­rate and low cost. Dam­age to the tar­get will de­pend upon the power of the laser and the time it spends on the tar­get. the Us navy has al­ready de­ployed 30-kilo­watt LaWs on­board the Uss Ponce which has been used in the Per­sian Gulf. the more pow­er­ful the laser, the less time it needs to spend de­stroy­ing the tar­get thus the Us navy is plan­ning 150kilo­watt LaWs.

Propul­sion Sys­tems

Queen el­iz­a­beth (Qe) class of royal navy's air­craft car­ri­ers have the lat­est in con­ven­tional tech­nol­ogy. Qe class air­craft car­ri­ers have a planned dis­place­ment of ap­prox­i­mately 65,000 tonnes, which may go up to70,000 tonnes in the fu­ture. the Qe-class air­craft car­ri­ers have an in­te­grated roll­sroyce elec­tric propul­sion sys­tem. rolls- royce pioneered the use of aero-de­riv­a­tive gas tur­bines in marine propul­sion, pri­mar­ily for naval ves­sels. the Mt30 Gas tur­bines that will power the Qe class air­craft car­ri­ers are the most pow­er­ful in-ser­vice gas tur­bines in the world. De­signed for the 21cen­tury navies, the Mt30 in­te­grates the very lat­est in gas tur­bine tech­nol­ogy and is de­rived from the highly suc­cess­ful trent en­gine pro­gramme. the propul­sion sys­tem has two Marine Trent MT30 36 MW (48,000 hp) gas tur­bine gen­er­a­tor units and four Wrt­sil diesel gen­er­a­tor sets (two 9 MW or 12,000 hp and two 11 MW or 15,000 hp sets). the trents and diesels are the largest ever supplied to the royal navy and jointly they feed the low-volt­age elec­tri­cal sys­tems as well as four Ge Power con­ver­sion's 20 MW Ad­vanced in­duc­tion Mo­tor elec­tric propul­sion mo­tors which drive the twin fixed-pitch pro­pellers.

Uss ford needs lots of elec­tri­cal power to sup­port fu­ture sys­tems like Emal, Em rail Gun, ad­vanced ar­rest­ing gear, dual band radar and laser weapons thus it has four 26-megawatt gen­er­a­tors, bring­ing a to­tal of 104 megawatts to the ship. Uss ford can man­age all this as its propul­sion sys­tem is nu­clear based. All fu­ture air­craft car­ri­ers who are go­ing to equipped with mod­ern sys­tems, will need lots of elec­tri­cal power which has to be catered for at the de­sign stage.

China’s air­craft car­ri­ers

China’s first air­craft car­rier Liaon­ing was orig­i­nally built as a heavy air­craft-car­ry­ing cruiser for the soviet navy. it was laid down as the riga and re­named the Varyag in 1990. A chi­nese travel agency pur­chased the un­fin­ished hull in 1998 and three years later the ship was towed from the Ukraine to china, where it un­der­went ex­ten­sive mod­ern­iza­tion of its hull, radar, and elec­tron­ics sys­tems. it was com­mis­sioned into the Plan

in septem­ber 2012 as a train­ing ship and af­ter two months PLAN con­ducted its first car­rier-based take­off and land­ings. Liaon­ing dis­places roughly 60,000 tonnes and its air wing con­sists of 24 shenyang J-15 mul­ti­role fighters. It is re­ported that China plans to fi­nally have four air­craft car­ri­ers as it was dis­closed that china had ac­quired four sets of air­craft car­rier land­ing sys­tems from rus­sia. true to its plan, launch­ing cer­e­mony of chi­naÕs sec­ond air­craft car­rier was held at the Dalian ship­yard of the china ship­build­ing In­dus­try Cor­po­ra­tion on April 26, 2017. the sec­ond air­craft car­rier is be­ing in­dige­nously de­signed and built by china. china started work­ing on it in novem­ber, 2013. At present, the main hull of this air­craft car­rier has been com­pleted and the main sys­tem de­vices in­clud­ing power sup­ply have been in­stalled in place.

In­dia’s Indigenous Air­craft Car­rier Project 71

in­dia de­cided to de­sign and make its own air­craft car­ri­ers thus was born indigenous Air­craft car­rier (iAc) Pro­ject71. ins Vikrant is the first ship of the Vikrant class of air­craft car­ri­ers be­ing built by cochin ship­yard. its launch­ing sys­tem is stOBAr with a ski-jump and dis­places about 40,000 tonnes. it is de­signed to take on MiG-29K and In­dian Te­jas fighter air­craft. In ad­di­tion it can carry 10 Kamov Ka-31 or West­land sea King he­li­copters for anti sub­ma­rine war­fare. it is pow­ered by four Ge LM2500+ gas tur­bines on two shafts, gen­er­at­ing over 80 megawatts (110,000 hp) of power. it was launched in 2013 and ex­pected to be com­mis­sioned in 2018. Apart from ins Vikrant there are plans to build the sec­ond car­rier Vishal with a dis­place­ment of 65,000 tonnes and cAtOBAr launch­ing sys­tem with eMAL from Us fi­nally in­dia plans to have three air craft car­ri­ers.

Indo US Joint Work­ing Group on Air­craft Car­rier Tech­nol­ogy Co­op­er­a­tion

this group has been formed to as­sist in­dia in the de­sign and con­struc­tion of mod­ern air­craft car­ri­ers. in­dian navyÕs con­troller of War­ship Pro­duc­tion & Ac­qui­si­tion rep- re­sents in­dia and Us is rep­re­sented by Pro­gramme Ex­ec­u­tive Of­fi­cer, Air­craft Car­ri­ers Us navy. the Group meets pe­ri­od­i­cally in in­dia and Us for dis­cus­sions on pro­vid­ing mod­ern air­craft tech­nol­ogy to in­dia. the meet­ings are also at­tended by other mem­bers as re­quired. Pro­vid­ing of eMAL un­der the fMs is very much on the cards.

tech­nol­ogy and cost comes in the way of late starters like in­dia and china who want to de­sign and con­struct their own air­craft car­ri­ers. Air­craft car­rier avi­a­tion re­ally does not de­pend that much on the car­rier but the com­plex sys­tem of avi­a­tion op­er­a­tions which fi­nally project power. US Navy has re­ally a high stan­dard in this field thus worth em­u­lat­ing.

PHO­TO­GRAPH: In­dian Navy

INS Vikra­ma­ditya op­er­ates a com­bi­na­tion of MiG-29K fighters, Kamov 31 & 28, Seak­ing, ALH and Chetak

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