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Combat Aircraft: AH-64 Apache (Combat Aircraft Series) PDF

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Preview Combat Aircraft: AH-64 Apache (Combat Aircraft Series)

6 OSPREY. COMBAT AIRCRAFT SERIES AH-64Apache BILL ~;UNSTOl\ COMBAT AIRCRMT SERIES AH-64Apache BILL G "ISTO"l . "'. . - 1 OSPREY PUBLISHING LONDON Published in 19l'l1;1)\ ()sprcy Pllhlishin/-CI,ul ~Il"mh('rClI1llpany"llllc{~'(lr1-{('Philip(;nJup ]2~J.I I.Ollg".\tTl" I~lIIdon \\'(;2E91.1' • -Illi.~IMMlk i"olpYliJ.{hlCd IImlt'rthe Ikmc(:On\cnlillll, .\lIliJ.{lllSl"t·....·l"\l'(l. A'JOlll 11"<1111all)'lair<kalillJ.{It)!"the PlllVIIS(.''Ifpri\.Ill:"tud}, l"t'!o(';tr<11.\.liti\.-iSI11nrH,\·jeW. OISIM,.'nlliul'd 1l11dl'rIII('(:op'lil-\"hl A11. 1~r14;.11111'"111 orIhi~pulilicttill11 lllil~ herepnl(hlCl'll.storedina TheAuthor l-l'llil'\'alSnlt·lIl.III'I1~lll!<lllilll'(l illall~ forlllorh~'all}" 1'1,11.1.GLI\STO:'>J. limlici RAFpilol amlll}illg II1t~lllS.dl'('1I"<mit".de.,Iil~1I.IhC1llit~ll. 1Il('ChaniGII. illslnlclor. isall illlC:I'1l;lIional1~ad:'llmdet!/-C\.'t!expe.·J1 oplicl!'plllll()("IlpyinJ.{.nxol'c1inJ.{III"01hl"lwise.willlllll! 011;lin:I~lli ;mcla\·ialioll all"airs, lie i,~Ihe<luth'l]"(If lhepriorIX'rmissio" ,II loppiJ.{hlOInl('r. Enquilies IlumerousIXlob1111 lhl"slll~I.,(·I.i:-';I l'nxlll('1l1 I shouldbeacldn....-.e:'(IIlIIll{' I'll]llisllC:I"l>. brnadGISlcr.wasIl'l'hniGJIcditorof"Fligll1 IIl1CrJlalion;l!"'alld\(.'chnol0l-\Tetlilllr()r"Sciellc~ .!oUrllal"·,;lIul isa~~i~lanl (1lmpilc1'tll"'j;\I1("sAll'rill' World"sAiRY.ln". I-Iei~lilt'authorofanolherIXMlk in Ihisseries.,'li(;-23f-27F{oggrJ". • (:lIl1!<IOIL.I\i!l Contents ,\I[.I~1 ,\p;ulw,-« >-'I'rl'\ 1~'11I1l;11 ;lilTI~lh) 1_'\Il;11h..(lit-lin'111"1)-11i'll>l~ Chaple,- I: l. rid\.· l)csig"nand Ik\'c1optlle1l1 (i~9,1:I:\T)~ U<;I~:\:I Chapter~: Technical Featun:s I.';I~N(kF,1IF,-i':!I-I Ch<lJ>ln:\: , ApadlcSI'll~()r,~ 17 ]'ypl.',~ctiJrFbirplan I'h'!IlI-I)l'I'M'ttillg"I,Ill. Chapln'l: I'rintl"dh~ l'rllost 11lH':l'IJa!ion;t1 Book I'rodllrtion, AI';lChc\Vcal)ll!lS ']'llrn!H)ut,lklgilllll. Ch"plt"l,l: .Il,illing-thc Anl'}' " (:I'!'lIlrarlmlrbhySdlQlligk~.©Bl'tIl<lnl Chapler11: Ftliti'lllSI,\(I, i\lariIIC;Llld Na\'YAll;lI'hl's Hi (:\Ila\\'a~dr;I\\'ill~,;::©Pil"l I'n'~sI,tel. Spl:t'iIil<IIitillS IX !)i;tg-r;Jms:'1'1(;.\ ;11111 \1ih'1-:('1.:11. Phllil>g'~lph~:'I'hl'Illlhli,slll'r~\\tllihIlikl'II)Ihallk :-'IrIlOlllldllxlug-bs(llug"lws)andIhe lJS Ik-paJ1lllcllt 01"1kkl1sc 101111('pholograph'rc:prodllu'(l ii, Ihi~ I)lMIJ.... , 1 Design and Development FE\'V FLYING machinesareas menacingas the desigtKd armed helicopters were considcrcd. Thc armed helicopter, and no armed helicoplcr is firSI 10 be built was sm;lll, a development ofthc Bdl more menacing than the apTly named 17 Sioux called the l'vlodel ~07 Sioux Scout. \Vith Apache. Though dull olive grey in colour, the only ~60hp, it did well to larry a crew of two-for Apaches look black as they come thumkring ill, the first,ime in a slim tam]cm cockpit reminiscentof making the air for miles ,lround vibrate wilh the a fighter-ami a chin turret with two machine guns. Illighty power of their threshing blades. Like <!m: Illdeed, small wings were fiued to help unload the some armoured insects, They dose with tbe enemy, rotor amI provide attachments for rockets or other shrugging off The hail of nrc directed against them wcapolls. Significantly, thc gUlluer was in the nose ;llld finally picking offlhick-skiutlcd lauks as if they and the pilot I.>t:hilld and slightly higher. were Aies. Vo,lilhin secouds [be Lllrobbing attackers havevanished, leavingbehilldascelleofcarnageand High-perfonnance requirement (\<.:sobtioll. 1]IH[clliably, the Allacllc is il11lJrcssivc, ,unl C;dCLl \-Vith increasinginvolvement in Vietnam,andhelafed laled to strike fear into its CllClllics. All tile sellior recognition thal existing- armed hdio)ll\(TS were COltllll,llH!crs of the US Army from President merely ordinary transpon11e1icoplers on to which a Reagan down !l;lve singled it out for special praise. few weapons had been fastened, Ihe US Army spellt NOl ltlltypical was the commellt of Brig-(;en Ellis 1964-65 devising- a specification for a specially de D.P;lrker, Deputy Director for Requiremell1.~: "It signed armed helicopler. R{joicillg in the tille of gives corps ;ll1d division cOlllmatH!ers Ille ()P!)()J-rLlll Advanc(.'"(1 Aerial Fire Support System (AAFSS), the ity to capitalize on more ofthe principles ofwarthan requirement called for a machine of unprecedented . . . with allV other system thev han'." But ;llllhis is only. performanceand<:apability, with theabilitytoHyand one side of" the coin. fight extremdy dose to the ground even at night or The other side is Ihat, whereas the Apache was ill bad. weathcr. III .\larch 19GG Lockheed was picked planned to cost $1.4 million, each oftoday's helicop ovC!" II othcr coutcstants for what promised to be a ters sets back the US taxpayer almost len times that giant programme. amonnt. And \Varsaw Pact armics are more COIll The first of ten prolOtypes of the AH-56A pletdydefend(.'"(1 againstairattack than anyothers in Chcycnlle hegan its Hight test programIllc Oil 21 hislory, with vast numbers of highly mobile SAMs Septcmber 1967. Powered by a 3,925shp General Glpahle with one shot of blowillg an Apache into Electric TG4 engine, it was in some ways almost au slllall fraglllellK (:0I1troversy over the viability of autogyro or even an aeroplane, because in cruising or hattlefield helimpters will cominue, but the point Hight much lhe lilt was provided by a wing. The must he notcd Ihat 110 nation makes g-reater use of main rotor was almost leathered, and "almost the tbem than the Soviet Union. Moreover, in Ihe new entire engine output" was supplied to lhe tail gear Havo<:, helicved to be the rVli-28, that country h:ls box where there was not only the usual ami-torque paid the Apache the most sincere form of compli rotor but also a propeller giving forward thrust. mellt possible, in the form of an apparently direct Cruising speed W;lS ~421llph (389km/h). Avionics copy. weresaid10 he "morecomplicated th;-lI1 a F.-52", with Early helicopters were incapable ofcarrying lUany inerti;ll and doppler navigation, terrain-following weapons, and it was not until the I960sthat purpost:- radar and amazingly cOlllplex systems for aiming a noseturret with a Minigun orgrenade launcher and a belly LUrret with a 30mm cannon. Missiles and rockeLS \"ere fired from under the winh'S. So great were the problems and cost.s that this bold and impn:ssi\'e machine nevcr went into production. ThcArmy'surgent needs in Vietnam \,'crc met by thesimpler AH-I HueyCobrd., produced \'cryquick ly by Bell as a private vcnture. In a brilliantly successful programme, thc Cobra has beCII con tinuously upb'Taded and dcveloped to such all ext.cnt that LOday's AH-IW l'or the Marine Corps has an installed horsepower of 3,392, compared with the original AH-l's 1,0001 To a rough approximation, lifting ability i... proportional to installed power, bm me Cobras find it difficult to opcrd.te except by day and in clear visibility. rore Abo,·C',19"mock-upoftheHughesYAH-64Apache, Warsaw Pact tankthreat runnuortht:winningdt:sign,whichwastochangeconsiderably. Accordingly, in 1972 the US Army at last got iLS aet FouryearsintotheAAH progrd.mme, in 1976,the togcther and, picking up where the AAFSS had left Hall Edward A. \fillcr, Assistant Secretary of the off, launched a programmc for an Advanct.'<1 Attack Arm)' (R&D), said: "The AAH's night vision and Helicoptcr (AAH). It was vinually forced into doing adverse weather capability, in concert with its agility, so by thc awesome and increasing power of t.he speed and vertical acceleralion, will deprive any Warsaw Pact armoured forces facing Western advancing armored force ofilS security. The AAH's Europe. Il wa!'>recognised that thecapabilities prom ised by the cancelled Cheyenne were not merely Iklo...:Thetwop~ofBell'srivalYAH-63losingde$ign which,amoOlgodIerthin,l;S,putthepilotinfrontofthe~nner desirAblebut absolutcl}'essential. andalsoreaturedatriC}"cle-typebndinggear. Above:TwoLockh(:edAH-56ACheyennesflyin.e;,werthetest facilityatO"nard,California,1968.TheAH-56A:wa$cancelled. was iJ different story. Bids were all in by 1 .\Iarch 1973, and on 22June of that year the Army picked maneuverability will enable it to dt:srroy tanks in Bell and Ilughes to receivecompetilivedevelopment rocky01' heavily wooded arC<l~where previously they COlltr.lCts, Each wastobuild two Ilightprototypesand would havebeen relmivcly s.afc from air<luCiek. one GTV (ground test vehide). In addition, Hughes "Soviet and Warsaw l~lCt units are .....ell equipped received an 'l\\'ard to develop a special gun for the for air defense, and the AAH is designed to survive AAH, BellelectingtousetheX\'IIR8b'l.ln byGener<ll 111 the hostile environment th<..'SC anti-aircraft Electlic. This partly explained the sUtrtling differ· weapons ",;11 create. Its abilit), will m'lke it a \'ery ence in the two development cOntnlcts. Bell's being dusi\'e target, and it is Glpable of sustaining (sic. he lor $44,7 million and Hughes' being pricc..-d at $70.3 mc:.1II1 tosay 'surviving') hits from 12.7mm machine million. b'l.lIl n>llndsand,in somevital areas,23mmweapons. Bell'sdesibYfl was the \-fooel 409. given the official It is also l."lluipped with an effecti\'c illfr-I-red sup designation VAH..63. It was the smallest helicopler pres,sion s)':'>tcm 10 protect it from heat-seeking mis Bell could dl.:sibYfl while still meeting lhe se\'ere siles. The AAH, with its night and advcl"SC-wcather mission rC<luirements. The 1700 enbolnc..'S were Glpabilities, will greatly reduce the qualitative armor placed quite low down behind the rolorgearbox, the ildvillItagc !lOW el~oyedby the East:' cowls being blended into the fuselage, Ahead ofthe rotortheentirefonvard fuselage wasoccupied bythe Five-company competition tandem cockpits, Ihe pilot bein~ in the nose and tl CPG(copilot/gunner)hehindand slightlyabove. The The AAH promised to be a m~jor programme, and XM188gun, a three·IXlrrcl 30ml11 weapon related to live comp..1.l\ies fought to win it: Bell Hdimpter, the M61 fighter gUll, ,'{as mounled under the ex Boeing Venol, Hughes Hel.icopters, Lockheed and treme nose, the visionics and sight system being Sikorsky. The one firm that could nOl lose was funhcr 1l<ICk underneath. Lmding gear was of the General [Iearie, whose speciallydesigned '1'700 tur fixed trit:yde type, with twin steerable nose\vheels. boshaft engine had aJready been picked nOtonly for The slender tailboom was indinc..--d up....'ards 10 gi\'e the AAH but also for the even more numerous dearancc ror the sweptback underfill at the tail, UTTAS (Utility Tactical Tr<lnspol1. Aircraft S}'slem) which wasalmostas bigas the upperfin carryingthe whkh waswonbythe Sikorsky$-70(VH·60A) Black smallhOtizolllilllailonlOp,theUtil rotorbeingonthe Hawk. As both helicopters \\'ere required to be end or the wilboom. The main rOlur had just two twin-engined, G[ was fairly safe in planningtobuild largeblades, Ihediameterbeing51fl lOin (15.54m). 5,000 oftheir new engine. But for the AAH itselfit Rearingin mind thalthe missions and theengines 5 were the same. the Ilug-hes Model 77. designated award. 011 ~~.Illile 1975.<11\(1 hy 19SqHenllx:rit had YAH-64. could hardly have beel1 lllore different in completed the 50 homs ofrunnillg necess.ary Ix:fore design. The engines Werc plan::d in separate boxes first flight ofeither flring prototype. The lauer was sfanding away fmm the rather lumpy humph..·Kked designated AV02 and AV03, meaning Air Vehicle fuselage. driving via diagonal shafts frolll sep..'lrate 02 and 03; AV02 made its lirst Hight at the Hughes gearboxes looking like slllalljet inlets on the front or Hightcentreat Palomar, Calilol'1lia,on 30September each cllh.-inc. The transparencies o\'er the cockpits 1975, one day inside the deadline. The first Bell were hugc. and the crew were seated the other war YAH-63 lIew next day. right on the deadline. at round COIll!l<II·e.::d witlt the Bell: fhe CPG being Arlington.Texas. Ilughes' AV0311e\\'on 22 No\'em markL-dly lowcrdown and in from. bel' 1975, while the second Bellllew 011 21 Decem Likewise, the positionsofthesight s)'stem and gun ber. were re\·cl~'<.1. the.:: sight being in the llOse and the By this time the IllIghesdesign had gone through gun 1Il1dcmcatlt. Lauding gear was 01" the tailwheel a metamorphosis. Mostsirikingofthe changes were type. the main units hiwing ungainly long legs slop al the tail. where the attachments for the tililplane,1I ing diagonally bach/ard and supported br shock the bottom of the taillxJom remained unused. In struts attached between their mid-points amI the stead the fin "'as extended upwilrds. with a SIl'lIlgC longeron at thebaseoftheC3noptC's. kinked shape and a G.tInhert.'(l (sideways lifung) aerofoil profilc, and the lailplane was placL'C1 right al Prototypetail details the top, pn~('-,(:ling far ahead of Ihe top of the fin. The nose W;L~ rc(k'signL'l1 with different sensors, TIle tail comprised a "crr low-mmllll,ed tailplane large cOlllpartlJleJlL~wcrc addL't1 on eac!l side ofthlC" (horil.Ont'llstabilizer)andaslightI)'swepl fin GITI'ring nose for avionics, and the ax:kpit and Gmopy wcre the tail rOlOr half-\"ay up. This rOI,or was unusual in tmallyR'Clcsih'lled witll giant flal tr.lllsparelllpancsill Ihat, 10reducenoisc. the fourbladeswcrenOi spact.-d strongframcs, tile light-haml windowsscn'ing;L<;lhe al 90". The main n,tnralso had four h];l(k's, and was access doors. Finally. in tht.'SC init.......1modificauol1s. remarkably small. though. like the Bell nnnr. it was the main-rotor mast W;L'i extcmk·d upwani<; by 9.5il1 full}",miculated with pitch-changebearinhTS. Rapping (~'I0111Ill), lx-c..'llIse ill cxtrcme Righi 1ll,\lI<kLlvres the hiubresand drag hingcs, The Hughes CTV. Gtlled AVOI. r:<ln iL~ nnors for Below:1neHughesAirVehiclesAVQ2and03onICSIin 1976. ThoughclearlyApaches,lheydifferedinalmQSIeo'errrespecl the firsl time cxactly IWO ),ears afler the.: contract fromtoda}"shelioopler.notablyin!henoseandtail. bladescould rub across the top ofthe canopy. explained later. this emerged as AGJ\.I-I14 Hellfire, During Phase I testing- availability of the two AVs and in am<~jorspecification change in February IY76 had been consistently above 86 per cent, considered this missile replaced TO\V as the primary weapon. all exceptional achievement. Atotalof850 hours had Bell and Hughes worked furiously to bring their been flown withoutaccident, ,Itspeeds lipto225mph prototypes to the stage at which, in mid-June 1976. (362km/h) forw,lrds and 32mph (83.7km/h) to the theycould be delivered to Edwards AFB, California. side and rear, at weig-Im 4,OOOlb (I,814kg-) hig-her for Army competitive evaluation. At the last minute than the desig-n mission weight and with lateral and one YAI1-6:~ h;ldan accident,on 4June,and the ReI[ vertical accelerations never before reached by a (~TV had to be frantically brought up to Hight status helicopter. A sustained rate of climb of 3,500ft/min as the replacement. (17.8m/s) had been delll(ll\strated, and prol()Jlged This did not help Rell's chances, and another testswith thecompany'sown XI\'1230Chain Gunand factor in Hughes' favour was the company's decision 2.75in rockeL~ had shown the YAH-6'1 to be a very al the st~lrt of the programme that it would necd a s1<lb[e firing platform. bigindustrial team toensurethatthe highestpossible level ofspc{:ialistexpertise would Ix: applied toevny Missilearmament major part. Apan from GEfor theengines, thisteam comprised: Bendix, dcnric power system, and main III theAAH specification the primary armameIll was transmission shafL'; and couplings; Bntea, hydraulic to be eightTO\V allti-tank missiles in twoquadruple flight controls; Garrett, engine IR suppressed ex launchers, though theprototypesdemonstratedtheir hausts and integrated pressurized' air systems; Hi ability to carry double this number. TOW requires a Shear, canopy and crew escape system: Litton (Preci hutIlan opnatar to guide it along the lineofsight all sion Gear Division), engine-nose and main transmis the way to the tal-get, and this obviously tends to sion gearboxes; Menasco, landing gears; Solar. gas fOl-ce the helicopter to expose itself throughout this 1UrbineAPU (auxiliary power unit); Sperry, autosta time to enemy lire. In 1973 the US Army began bilization; Teledyne Ryan, airframe struClure; Tele development of a new-generation ami-tank mi~sile dyne Systems, !-ire-control computer; Tool Research which would not need this form of guidance. As and Engineering:, main and tail rotor blades; and \Vestern Gear, intermediateand tai[ rotorgearboxes. Below:FiringsomeofthefirstFFARs(folding-finaircraft At theendof [976 it all came rightfor the JIughes rockets)from AV02.,incffedtheveryfirstApacheprototype. AtthistimenooperationalsensorswerecalTlcd. tealll. The AII-64 was announced the winner, and 7 the company also won the gun competition with its pre-produClion prolotypes, AV04, flew on 31 Octo unique Chain Gun. Ilughes immediately H.'ceived a ber 1979. $317.7 million COntT<lct for FSD (full-SGllc develop- Here was yCt another new arrangement. with an ment)oftheproposL--d productionhelicopter,indud all-moving "stabilator" mounted low down right at ing the construction uf three more prototypes the backofthe helicopterextending fromjustabo"e AV(}il. 05 and 06---the I:lSI IWO with airfr.IIllc..'S sub tJle vel)' tip of the tailhoom. 111is enlargl.."t! surf"ICe contral..1ed to Teledyne Rpm at San Diego. wasdl;ven bya hydr.llllic1>O\\'er unit linkc...d into the '11lf()IlgholU 1977 HlIght.'S Aew theIWO prototnx..'S Aighl-<:omrol and autosu.h system to till the machine at Palomar, testing and evaluating a "Mod I" pack when necessary but in normal flight 10 prcSCI'\'e a age ofch;ll1g-cs which earlier flying had shawl! LO be horizontal auitude 110mailerwhat thecin:umstances. desirahle. These chauges induded a funher Gin Thl: new tail also had a vertical fill 3in (7Gllll1l) taller (152mm) increase in main rowr mast height. SWCpl c.'lTying a modified tail rowr a lull 30ill (0.76m) hack lips 10 the main-rotor blades to reduce com higher up. ["en this was Ilot quite the answer, and pressibilit),. il redesign of the I<lilplane to have a 011 1'1 March 1980 AVO"! Acw with a smaller slahila re,-ersed planfo~m (slraiglll 1c;lding edge and ta lor, followed two days later by the first flight ofthc pered trailing edge). a 3in (76mm) increase in dia AVOG whkh also imroducl..,<1 a tail 1'0101' of lOin meter of the tail rotor, and inslallation of Ihe first (254mm) b'Teaterdiameter. p"iItel'll of IR suppressed cxhalL..t using not the Backin f\larch 1979AV02 hadGtrriedOlllthefifSl engine·dri,·cn fans originally spL't-ified btl( the (ground) firing ofa Ilelllire mis."iilc, followed laterby Hughes Hlack Hole Iype()fp"lssi\'ecoolingbox using airborneshoL..ag<linsldesignaLCd ldrgets. In Oclober self-illduc("d airflow to mix with the hotgas. 1979 02 Glrricd 01lt the first autonomous firing, desi~n;lling Lhe larget itself with its own Martin Phase II testing \farieua TADS. Butits sister.ship 03. was fitted with rival sensors by Northrop ;..Jortronics, and it was not These changes had all beell Aown by May 1978. By lIntil f\'!al'ch 19RO that the Martin installation was this lime AV02and 03,aftera mmbined lotal of720 :.mnouncedasthewinner. This naturallyaffected not hours. were grounded in order 10 be broughl up to only the shape of the nose bUI also the brian! side full produoion SL.indal'd for Ph<c>c II testing. This avionics panniers. Yet another visible ch;.mge was 56-month pro(~rramme,coslcdat$390million includ that the flat gL"lSS cockpit panels ....·ere replact.'d by ingthethn.'ceX{T<!PT"Otot)pC_'S, \\~d.~ thefinal longhaul .~ingle"cul'\'<l.lure bulged windows gi,'ing a "K:W thai had 10 be completed prior 10 Ihe SL.i11. of almost directly downwards or to the rcaI', though pnKluaion. ModifiG.ltions kept lx:ing introduced. downwards view is slightly limited by the long When protOlypcs 02 and 03 resumed flying, respec ;wionics bays. tively in Novcmber and December 1978, the)' in Theonly m<tiorsetback in theprogrammecamcin corporated thc Mod 2 package which indudl..>d all Novemher 1980 when 04 wasdestroyed in a mid·air wiring for the mission avionics (though tbe vital collision in no way due to allY fault in the helicopter. scnsors had still not been selected). Completely new This machine had just completed a programmc of 3viollic;bayswcrcconstructed,startingIleal'Ihe nose weapon ltials using all planllcd types of armament, and extending back under the wing. enclos.illg lhe and 02 alld 06 cominued the work using Ihe Pilot's upperp:.lrt 01"each main gearon the wa)'. Night Vision S)"Stem (P:'\lVS) in an important selics Even more obvious W.IS continuing uncel1ainty of night filings. O\'erthe horizomaltail. The fixed T-tail wassatisfac President Rcag<m signed the FY82 (Fiscal Year tory in most conditions, btU at extremely 10\\' level 1982) Defense Bill on 19 December 1981 in which so-Gllk,,1 NOE (nap of the E.al1h) flying-it let the was an item for $537.5 million for the first II tail sink d()\\'n and the llOSC point skywards, deman production Apachc..'S. Hughes announn.·d plans to ding major forward stick movements at times when build an assembly plalll on a virgin sitc at MeS<I, cockpit workload was high in any case. AV03 Aew Alil.ona, and this openl.."tl in Februa'1' 1983. On ~-SO with a low lailplane. but something close to the September 1983 PVOI, the first production.vehicle, or definitive tail was not seen Ullliithe first the new was rolled out. 2 Technical Features T HE HEART of any helicopter is its rotor actua!ors between the pilot's scal ;:lIId the main system, and (hatofthe Apacheisa C<'1refully gearbox. Following major h}'draulic failure the sys considered blend oftradilional practiceand lem auton.latioll)'switches toSpcn)'secondal)'back new technology. Though it has passed through im lip FBW (lly-by-wire) electrical signalling. IXln:i11ll stages of modificltion, the main rotor h;:l'\ An unusual fealUre is that all major stresses are always been full)" artl(."ulaled .mel had fnur bladt's of transmitted \'iaa fixed rotormast from thebottomof relatively small diameter resulting in unusually high which the helicopter is hung ,'ia four (ubular \'ee di5C loading (as in the small Hughes Cayusd struUi. Themaingearbox ishungunderthecentreof Defender family). Eadl uf the four inlcrdlangeable the fixed mast and drives via a tubular shaft passing bladl..'S h,l.." a bmad dl0n:1 and a highly Cl.mbered up the centre to the rotor hub spinning on roller aerofoil st.'l.Uon. As nOlc:.'t1 pre"iously. the tips are bcarinb'S at the top of the fixed mast. This prO\ides rak(.,,(] backwards to rtxlucc compressibilil)' problems dual redundant load paths. and allows the lr.msmis 011 the ad\·ancing blades. For transport by Glrgo sion to Ix:: rcmovl.-xi while kl..."Cping the rotorin place. aira-afLcadl bladeam readilybe folded through 90<> No bearing lubrication is Ill."t.."(k-xi in the main rotor. or remo\'c:."t.I aud stowed. and the intenlll.."diatc..: and tail-rotor gearboxes arc Rotorbladestructure 80:10"·:Thanks10i~sheeTPOWeTtheApKhcis~k.Puttingon Fullpo".""andslammingthecyclic,,"tid:ForwardFormaximum ForwardsaccelerationputstheApacheinfOthisanirude. Each blade has live parallel sp.1;r.s of high-strength stainlesssteel,separated and linedbystmourallUhes of glassfibre. Laminated skins of I,hin Sl;links.~ steel are wrapped I1Hmd from the fronl., Ihe number of laminations vel)' rapidly increasing ;1I the root to form a solid stack ofretcmion straps through-bolted together. The trailing portion of cach blade is of compositehoneycornbstruUurebondedon separate ly. TRE AclvilnCI...>d StruC!urcs Division were required to demonst.rate sustained operatioll under the most severe cOllditions with olle steel skin cracked across and any aile spar ShOI through. At the root the multiple laminates are allowed to pivot upwards by <tn offscl flapping hinge, and to nxk to fronl and rear in lhe plane of the disc by c1astollll::li, Ica&1ag dampers. Anti-"ibration masses are attached al from and rcar of eadl rOOI on the leadllag tic rods. !)ildlchangesare introduced in lhe usual way by n::nicaltie rods from the lIppe,- (rotat ing) swashplmc, the non-rotating !o\,'er swashplate being tilted according to lIight-eontrol input de mands by three po\\'erful Parker Rertea hydraulic 9

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Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.