SI STEMA MASDE MO MOTORESDE COMBUS USTI ON I NTERNA PRATT & WH WHI I TNEY JT8D17
Mar i aNat al yLópe zMay a Ed ga rJ o eZa v a l e t aEs c o b e d o Gr upo :6AM1
Contents
Introduction ………………………………………………………………………………..3 Power plant - description and operation………………………….…….….……………4 Engine cowling - description and operation 71………………………………………...6 Engine fuel deicing system - description and operation………………………………8 uel flow indicating system - description and operation……………………………11 Ignition system …………………………………………………………………………..14 Engine anti-icing - description and operation………………………………………...1! Engine e"austing system………………………………………………………………..#1 $%rust re&erser system……………………………………………………………..…...#3 $%rust re&erser - %ydraulic actuators and sync s%afts……………………………….#' Engine starting…………………………………………………………………………...#6 (enerator cooling - description and operation………………………………………..#8 Engine control system - description and operation…………………………..………3) Engine indicating * description…………………………………………………………3# $%rust re&erser - description and operation…………………………………………..34 Engine oil system - description and operation…………………………………..……36 Pneumatic starting system - description and operation……………………………...4) +i,liograp%y………………………………………………………………………………4#
Introduction
$%e $8 engine is an a"ial flow / dual w%eel and fully s%aped product. Its design ,egan in 0pril 1!6) . $%e $8 engines - 7 to 17 are used in t%e following aircraft + 7#7 and 737 / 2connell ouglas -! / 0erospatiale uper ara&elle and aa, 5irgin $%e $8 engine %as pro&en itself to ,e a %ig%ly dura,le and relia,le engine/ %a&ing completed more t%an 673 million dependa,le flying %ours since entering ser&ice. nce deemed t%e wor%orse of t%e industry/ more t%an 14/7') $8 engines %a&e flown. $oday/ t%ere are #/4)) engines still in use.$%e eig%t models t%at mae up t%e $8 family co&er a t%rust range from 14/))) to 17/))) pounds. $%e $8-# $8-#)) )) series/ series/ w%ic% w%ic% entered entered ser&ice ser&ice in 1!8)/ 1!8)/ offers offers 18/')) 18/')) to #1/7)) #1/7)) pounds of t%rust/ and is t%e e"clusi&e power for t%e popular 2-8) series aircraft. $%e $8-#)) ,uilds on t%e familys e"cellent relia,ility and low maintenance costs w%ile meeting noise and emissions regulations.Pratt 9 :%itney %as de&eloped a new low-emissions com,ustion com,ustion system/ or E-;it/ t%at is 0< 0< #'-certified #'-certified to ensure t%e $8-#) $8-#)) ) engine engine stays stays current current wit% en&iron en&ironment mental al regulati regulations. ons. $%e E-;it E-;it reduces $8-#)) engine =" emissions ,y #' percent and e"ceeds all I0 standards for new production engines..
Ilustración 1
2ain components
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>ow pressure compressor ? si" stages@ Aig% pressure compressor ?se&en stages@ om,ustion section ?nine com,ustion c%am,ers@ Aig% pressure tur,ine ?one stage@ >ow pressure tur,ine ?nine stages@ cape pipes (ear ,o"
0ll supported supported ,y nine ,earings ,earings
POWER PLANT - DESCRIPTION AND OPERATION
$%e 7#7 airplane is powered ,y t%ree $8 tur,ofan engines ?figure 1@ mounted on t%e aft fuselage area. $wo engines are strut mounted/ in con&entional nacelles/ one on eac% side of t%e fuselage. 0 center engine engine is mounted mounted aft aft of t%e fuselage fuselage structure. structure. 0ir is ducted to to t%is engine engine t%roug% an inlet forward of t%e &ertical fin Bust a,o&e t%e fuselage. Eac% engine is secured to t%e engine mount fittings at t%ree points. $wo cone ,olts/ attac%ed to a dou,le flange at t%e fan disc%arge intermediate case/ and one cone ,olt attac%ed to a dou,le flange at t%e fan disc%arge tur,ine e"%aust outer duct/ secure t%e engines to t%e forward and rear mount fittings. 0ccess to t%e side engine e"terior components is pro&ided ,y %inged remo&a,le upper and lower cowl panels w%ic% may ,e opened from eit%er side. enter engine access is made t%roug% four %inged remo&a,le side cowl panels. 0ccess to t%e center engine inlet and nose dome is gained t%roug% an access panel a,o&e t%e aft airstairs in t%e center engine inlet duct. +. $%e maBor accessories fitted to eac% engine include a constant speed dri&e unit/ a pneu pneumat matic ic start starter er// and and =1 and and =# tac%o tac%omet meter er gener generat ators ors.. 0 gene generat rator or is mounted on t%e constant speed dri&e unit. Aydraulic pumps are installed on engines =o. 1 and #. ire detection and fire e"tinguis%ing systems are pro&ided in eac% engine area. . $%e engine starting system pro&ides a means of rotating t%e =# compressor to esta,lis% a flow of air t%roug% t%e engine.
Ilustración 2
. 0ir is ,led from t%e low pressure and %ig% pressure compressors and t%e fan disc%arge duct to operate &arious airplane systems. 0 t%rust re&erser/ attac%ed to t%e e"%aust section of eac% engine pro&ides a means of retarding t%e forward speed of t%e airplane after touc%down. E. 0 four compartment drain tan is mounted on t%e under side of eac% engine. >eaa >eaage ge fluids fluids from from t%e t%e seals seals and and dri&e dri&e pads pads of t%e engin engine e acces accessor sories ies are drained/ t%roug% tu,ing/ to t%e tan. n engines wit% t%e fuel pressuriDing and dump &al&e drain port not plugged/ fuel disc%arged from t%e &al&e also drains t%roug% tu,ing to t%e tan. 0 drain line is installed ,etween t%e oil tan scupper and t%e drain tan/ to collect oil spilled during ser&icing. In flig%t/ air flowing past a drain mast/ on t%e engine cowling/ creates a negati&e pressure w%ic% sucs t%e fluids o&er,oard t%roug% a disc%arge manifold. iffy drains are pro&ided on t%e under side of eac% tan compartment to permit draining t%e tan w%ile t%e airplane is on t%e ground.
ENGINE COWLING - DESCRIPTION AND OPERATION OPERATION 71
0. $%e engines are co&ered ,y cowl panels to pro&ide a smoot% airflow o&er t%e engine and to protect e"terior engine components from damage. $%e cowl panels for t%e side engines include a nose cowl/ upper and lower %inged remo&a,le cowl pane panels/ ls/ and and a fi"ed fi"ed cowl cowl panel panel.. $%e $%e cente centerr engin engine e is co&e co&ered red ,y four four %inge %inged d
remo&a,le side cowl panels. 0 nose dome is also fitted on eac% engine. $itanium and steel fires%ields are ,onded to t%e inside of t%e outer sin in areas in w%ic% a fire may occur. $%e cowl panels are designed to ,e drip-free. rain %oles and drain tu,es in t%e lower surfaces of t%e cowl panels collect any engine leaage fluids in a drain manifold to ,e e"%austed o&er,oard in flig%t. •
enter Engine owl Panels
$%e center engine cowl panels form part of t%e aft fuselage contour. $%e forward left and rig%t panels fair wit% aft fuselage sin. $%e aft panels fair wit% t%e t%rust re&erser s%roud ring and t%e t%rust re&erser actuator fairing. Eac% panel is %inged at t%e top ,y fittings on t%e center engine support ri,. $%ree %oo latc% fasteners Boin opposite opposite panels panels at t%e underside underside of of t%e engine. engine. $wo $wo safety safety latc%es latc%es at t%e top top of eac% eac% panel panel pre&e pre&ent nt an open open cowl cowl from from ,eing ,eing remo& remo&ed ed until until t%e t%e latc% latc%es es are are depressed. $%e safety latc%es automatically trip into t%e loced position w%en t%e panels are closed. 0n indicator on eac% safety latc% s%ows w%en t%e latc% is in t%e loced or unloced position. Aold open rods/ installed in eac% panel/ allow t%e panels to ,e propped in t%e open position. afety pins are pro&ided to loc t%e rods in eit%er t%e open or stowed position. +. $%e left forward cowl panel is pro&ided wit% an access door to facilitate ser&icing t%e engine oil tan. n preferred cowl installations an access door is also pro&ided in t%e left forward cowl panel to manually operate t%e starter s%utoff &al&e. E"%aust ports are pro&ided on t%e left aft cowl panel to accommodate engine gearcase ,reat%er air and on t%e left forward cowl panel/ to e"%aust fuel %eater air and constant speed dri&e oil cooler air. 0n e"%aust port on t%e rig%t aft cowl panel is pro&ided to e"%aust generator cooling air. 0n o&er,oard drain mast/ installed on t%e rig%t aft cowl panel/ e&acuates t%e engine fluid drain tan during flig%t. $%ree ,lowout doors/ one on t%e rig%t forward cowl panel and two on t%e rig%t aft cowl panel/ relie&e e"cessi&e pressure w%ic% could de&elop wit%in t%e cowling during a fire. •
ide Engine
$%e side engine upper and lower cowl panels fair wit% t%e engine nose cowl/ wit% a fi"ed cowl panel attac%ed to t%e in,oard side of t%e engine/ and wit% t%e t%rust re&erser s%roud ring i" %oo >atc% fasteners attac% t%e upper and lower cowl panels to t%e fi"ed cowl panel. i" ot%er %oo latc% fasteners Boin t%e upper and lower cowl panels toget%er. $%ree forward and t%ree aft pin latc%es ensure positi&e attac%ment of t%e cowls and ser&e as %inges permitting eac% panel to ,e opened from eit%er side. Aold open rods for eac% panel are stowed on t%e engine/ t%e nose cowl aft structure/ and on eac% panel
. Ilustración 3
+. penings are pro&ided in t%e lower cowl panel for t%e engine gear,o" ,reat%er/ ,reat%er/ t%e constant speed dri&e cooling air e"%aust/ e"%aust/ t%e generator generator cooling air e"%aust/ e"%aust/ an o&er,oard drain mast/ and an oil tan access panel. n preferred installation/ a starter o&erride and access door is also fitted to t%e lower cowl panel. $%e upper cowl panel is fitted wit% a ,lowout door. •
ide Engine =ose owl
$%e nose cowl is ,olted to t%e forward flange of t%e side engine inlet case. It is s%aped to o,tain a smoot% airflow o&er t%e engine and to pro&ide an optimum airflow to t%e engine compressor inlet ?ig. 3@. 0n anti-icing air inlet is located on t%e rear face of t%e nose cowl at appro"imately t%e ! oFcloc position. $%ree pin latc%es/ two on t%e in,oard side and one out,oard/ Boin t%e nose cowl to t%e upper and lower cowl panels. 0 constant speed dri&e cooling air scoop is located on t%e underside of t%e nose cowl. $%e nose cowl is anti-iced ,y engine ,leed air ?
ide Engine i"ed owl Panel
0 four piece fi"ed cowl panel/ mounted on t%e in,oard side of eac% side engine/ engine/ fairs wit% t%e upper and lower cowl panels. $%e fi"ed cowl supports t%e side engine upper and lower cowl panels.
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=ose ome
0 nose nose dome is mounted mounted on eac% eac% engine to pro&ide pro&ide a smoot% airflow airflow o&er t%e front front accessory accessory dri&e %ousing. %ousing. $%e nose dome co&ers t%e =1 tac%ometer generator. 0n 0n inlet pressure sensing pro&e ?Pt#@ is mounted in t%e center of t%e nose dome.
Ilustración 4
ENGINE FUEL DEICING SYSTE - DESCRIPTION AND OPERATION OPERATION
0. Engine fuel deicing system detects t%e presence presence of ice in t%e fuel and pro&ides pro&ides controlled controlled %eating of fuel to melt t%e ice. uel generally contains suspended suspended water droplets w%en t%e temperature of t%e fuel falls ,elow t%e freeDing point of water. $%ese suspended water droplets freeDe and form ice. Ice e&entually clogs t%e engine main fuel filter and restricts normal fuel flow to t%e engine. +. $%e engine fuel deicing system for eac% engine consists of a fuel deicing %eater/ fuel deicing deicing air &al&e/ &al&e/ fuel fuel deice deice control control switc%/ switc%/ &al&e-i &al&e-in-tr n-transi ansitt lig%t/ lig%t/ fuel filter pressure switc%/ fuel icing warning lig%t/ and t%e necessary tu,ing. $%e fuel %eater/ fuel filter pressure switc%/ and fuel deicing air &al&e are mounted on t%e engine. $%e fuel deice control switc%/ &al&e-in-transit lig%t and fuel icing warning lig%t are on t%e t%ird crewmanFs lower panel. . :%en ice clogs t%e engine main fuel filter/ pressure differential across t%e filter ,uilds up/ t%e fuel filter pressure switc% closes and t%e fuel icing warning lig%t illumi illuminat nates. es. $urni urning ng on t%e fuel fuel deice deice contr control ol switc switc% % permi permits ts %ig% %ig% pres pressur sure e compressor air to pass t%roug% t%e fuel deicing %eater air tu,es and %eat t%e fuel. $%e warm fuel passes t%roug% t%e fuel filter and melts t%e ice. :%en t%e ice is melte melted/ d/ t%e t%e fuel fuel filter filter pres pressur sure e switc switc% % open opens s and and de-en de-ener ergiD giDes es t%e t%e fuel fuel icing icing warning lig%t/ t%e fuel deicing control switc% is t%en turned . $%e fuel s%ould ,e %eated intermittently. •
uel eicing Aeater
0. $%e %eater is an air-fuel %eat e"c%anger and consists consists of a %ousing containing containing a core composed of air tu,es/ a series of ,affles/ and a fuel ,ypass &al&e %eater is mounted on t%e fuel control unit ,etween t%e ,oost and main stages of t%e enginedri&en fuel pump.
Ilustración 5
+. $%e fuel flowing to t%e main engine fuel filter passes t%roug% t%e %eater at all times. It is %eated/ only w%en t%e fuel deicing air &al&e is open and permits %ig% pressure compressor ?13t% stage@ ,leed air to pass t%roug% t%e %eater air tu,es. $o o,tain uniform %eating %eating of t%e fuel/ it is ,affled around t%e air tu,es. In an e&ent t%e %eater ,ecomes clogged/ a ,ypass &al&e permits t%e fuel to ,ypass t%e %eater and flow directly t%roug% t%e fuel filter to t%e engine. •
uel eicing 0ir 5al&e
0. $%e air air &al&e is used used to control t%e t%e %ig% pressure pressure compressor compressor ?13t% ?13t% stage@ ,leed ,leed air flow t%roug% t%e fuel deicing %eater ?ig. 1@. It consists of a ,utterfly &al&e and an electri electrical cal actuato actuatorr ?motor@. ?motor@. $%e &al&e &al&e %as an o&errid o&erride e %andle %andle for manually manually positioning t%e &al&e and t%is same %andle can ,e used during maintenance to determine &al&e position. $%e air &al&e is operated ,y a fuel deice control switc%/ located on t%e t%ird crewmanFs lower panel. $%ere is one air &al&e for eac% engine located at t%e # oFcloc position slig%tly forward of t%e engine mount ring. •
uel ilter Pressure witc%
$%e pressure switc% senses t%e pressure differential across t%e engine main fuel filter. $%e $%e pressu pressure re switc switc% % is moun mounted ted direc directly tly on t%e filter filter.. If t%e t%e engine engine fuel fuel filte filter r ,ecom ,ecomes es clogg clogged/ ed/ pressu pressure re diffe differe rent ntial ial acros across s t%e t%e filte filterr ,uild ,uilds s up. up. :%en :%en t%e t%e
press pressure ure diff differe erenti ntial al reac reac%es %es 4.4 to '.8 psi/ psi/ t%e press pressur ure e switc switc% % closes closes and and illuminates t%e fuel icing warning lig%t on t%ird crewmanFs lower panel. :%en t%e pressure differential again decreases/ t%e pressure switc% opens and t%e fuel icing warning lig%t goes off. •
peration
0. $%e engine fuel deicing system recei&es its power from 11'-&olt 11'-&olt ac ,uses t%roug% circuit ,reaers on circuit ,reaer panel. +. :%en ice is present in t%e fuel it will e&entually clog t%e engine main fuel filter and cause t%e pressure differential across t%e filter to increase. :%en t%e pressure differential reac%es 4.4 to '.8 psi/ t%e fuel filter pressure switc% will close and illuminate t%e fuel icing warning lig%t on t%ird crewmanFs lower panel. Placing t%e fuel deice control switc% to = position opens t%e fuel deicing air &al&e. Aig% pressure compressor ,leed air ?13t% stage@ passes t%roug% t%e &al&e into t%e %eater air tu,es and %eats t%e fuel. $o o,tain a uniform %eating of t%e fuel/ ,affles in t%e %eater core direct t%e fuel around t%e air tu,es in a controlled flow pattern. $%e %eated fuel flows to t%e fuel filter and gradually melts t%e ice clogging t%e filter. :%en all ice is melted/ pressure differential across t%e filter decreases and t%e fuel filter pressure switc% opens/ deenergiDing t%e fuel icing warning lig%t. $%e %ot airflow t%roug% t%e %eater is stopped ,y placing t%e fuel deice control switc% to position. :%ene&er t%e fuel deicing air &al&e is in transition/ t%e &al&e-intransit transit lig%t lig%t on t%ird t%ird crewman crewmanFs Fs lower lower panel panel will will illumina illuminate. te. $%e deicing deicing %eater %eater s%ould ,e used intermittently. . If t%e fuel filter ,ecomes clogged/ t%e fuel icing warning lig%t will remain on/ and t%e filter pressure differential will continue to increase until t%e filter ,ypass &al&e opens. $%e entire fuel filter system must ,e cleaned and c%eced after operating under t%ese conditions. If t%e fuel deicing %eater itself ,ecomes clogged/ a ,ypass &al&e permits t%e fuel to ,ypass t%e %eater and flow directly t%roug% t%e fuel filter to t%e engine.
Ilustración 6
FUEL FLOW INDICATING SYSTE - DESCRIPTION AND OPERATION
0. $%e function function of t%e fuel flow indicating system system is to pro&ide a &isual indication in t%e contro controll ca,i ca,in n of t%e t%e fuel fuel consu consumpt mption ion rate rate in ilog ilogra rams ms per %our for for eac% eac% indi&idual engine. +. $%is system %as t%ree fuel flow transmitters/ t%ree fuel flow indicators/ and one fuel flow power supply unit. 0 fuel flow transmitter is located on t%e forward left side of eac% engine. 0ll t%ree fuel flow indicators are located on t%e t%ird crewmanFs lower instrument panel. $%e fuel flow power supply unit is located on t%e E'-1 eGuipmen eGuipmentt rac rac on 7#7-1) 7#7-1)) ) eries eries 0irplane 0irplanes/ s/ and is located located ,e%ind ,e%ind t%e t%ird t%ird crewmans panel on 7#7-#)) eries 0irplanes ?ig. 1@. . :%en t%e system is energiDed t%e fuel flow power supply unit supplies constant constant freGu freGuenc ency y 3-p% 3-p%ase ase powe powerr for for dri&i dri&ing ng t%e t%ree t%ree fuel fuel flow flow transm transmitt itters ers.. Eac% Eac% trans transmit mitte terr sense senses s t%e mass mass rate rate of fuel fuel flowi flowing ng to its respe respect cti&e i&e engin engine e and and generates an electrical signal proportional to t%is flow. $%e electrical signals are transmitted to t%e fuel flow indicators w%ic% s%ow t%e fuel ,eing consumed in ilograms per %our ,y t%eir respecti&e engines. . Eac% fuel flow transmitter measures t%e amount of fuel flowing to its respecti&e engin engine e and and pro& pro&ide ides s a corres correspon pondin ding g signa signall to its resp respect ecti&e i&e indic indicat ator or.. $%e $%e indicator indicator uses t%is signal to pro&ide a &isual indication of t%e rate of fuel flow to t%e engine.
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uel low Power upply Hnit
0. $%ere are two types of fuel flow power supply units. ne is electromec%anical electromec%anical and t%e ot%er newer unit %as solid state circuitry. +ot% units furnis% a constant freG freGue uenc ncy y pow power sour source ce for for t%e t%e fuel fuel flow flow tran transm smit itte ters rs and and ,ot% ,ot% unit units s are are interc%angea,le in t%e airplane. $%e electromec%anical unit consists of a sync%ronous motor connected to a 3 ,ar comm commut utat ator or t%ro t%roug ug% % a redu reduct ctio ion n gear gear.. :%en :%en t%e t%e moto motorr is ener energi giDe Ded d t%e t%e commutator is dri&en at a constant speed. 0s t%e commutator rotates it c%ops t%e dc current to produce a simulated 3-p%ase / 4-cycle ac current. ilters are installed in t%e unit to ensure t%at t%e output is free of radio noise. $%e solid state unit produces t%e same output to t%e fuel low transmitter ,y electronic means. •
uel low $ransmitter
0. $%e fuel flow transmitter transmitter consists of a %ousing containing containing two identical cylinders cylinders placed end-to-end so t%at t%e a"es of t%e cylinders coincide. $%e upstream cylinder is named t%e impeller and t%e downstream cylinder is named t%e tur,ine. $%e %ousing fits closely to t%e outer diameter of ,ot% t%e impeller and t%e tur,ine. 0round t%e perip%ery perip%ery of t%e circular cross section section of t%e cylinders/ cylinders/ at a fi"ed radius from t%e center/ are a num,er of eGually spaced %oles w%ic% are accurately parallel to t%e a"es of t%e t%e cylin cylinde ders. rs. Hpstre Hpstream am of t%e t%e impell impeller er is t%e impelle impellerr motor motor.. ownstream of t%e tur,ine a second %armonic transmitter is attac%ed to t%e tur,ine wit% two sets of springs of different torGue gradients used to restrain it. $%is permits a two-slope scale on t%e indicator allowing greater sensiti&ity at low flow rates. =$E $o pre&ent dry operation damage and to prolong t%e life of t%e transmitter/ it is recommended t%at t%e HE> >:J circuit ,reaers ,e pulled ?open@ w%ene&er t%e t%e engi engine ne fue fuel feed feed line line is drai draine ned d or t%e t%e airp airpla lane ne is out out of ser& ser&ic ice e for for maintenance. +. $%e impeller motor dri&es t%e impeller at a constant angular &elocity/ t%us as t%e fuel passes t%roug% t%e impeller it is gi&en a &elocity at rig%t angles to t%e direction of flow. $%is angular &elocity constitutes a c%ange in t%e momentum of t%e fuel directly proportional to t%e mass of fuel flow. 0s t%e fuel passes t%roug% t%e tur,ine/ t%e angular component of t%e momentum is remo&ed/ t%is imparts to t%e tur,ine a torGue directly proportional to t%e mass rate of fuel flow. $%is $%is torGu torGue e rotate rotates s t%e impel impeller ler again against st cali, cali,ra rate ted d sprin springs gs and and positi positions ons t%e t%e magnet in t%e second %armonic transmitter to a position corresponding to t%e fuel flow is named t%e tur,ine. $%e %ousing fits closely to t%e outer diameter of ,ot% t%e impeller and t%e tur,ine. 0round t%e perip%ery of t%e circular cross section of t%e cylinders/ at a fi"ed radius from t%e center/ are a num,er of eGually spaced %oles w%ic% are accurately parallel parallel to t%e a"es of t%e cylinders. cylinders. Hpstream of t%e impeller is t%e impeller motor. ownstream of t%e tur,ine a second %armonic transmitter is attac%ed to t%e tur,ine wit% two sets of springs of different torGue gradients used to restrain it. ?ee figure #.@ $%is permits a two-slope scale on t%e indicato allowing greater sensiti&ity at low flow rates.
Ilustración 7
=$E $o pre&ent dry operation damage and to prolong t%e life of t%e transmitter/ it is recommended t%at t%e HE> >:J circuit ,reaers ,e pulled ?open@ w%ene&er t%e t%e engi engine ne fue fuel feed feed line line is drai draine ned d or t%e t%e airp airpla lane ne is out out of ser& ser&ic ice e for for maintenance. +. $%e impeller motor dri&es t%e impeller at a constant angular &elocity/ t%us as t%e fuel passes t%roug% t%e impeller it is gi&en a &elocity at rig%t angles to t%e direction of flow. $%is angular &elocity constitutes a c%ange in t%e momentum of t%e fuel directly proportional to t%e mass of fuel flow. 0s t%e fuel passes t%roug% t%e tur,ine/ t%e angular component of t%e momentum is remo&ed/ t%is imparts to t%e tur,ine a torGue directly proportional to t%e mass rate of fuel flow. $%is $%is torGu torGue e rotate rotates s t%e impel impeller ler again against st cali, cali,ra rate ted d sprin springs gs and and positi positions ons t%e t%e magnet in t%e second %armonic transmitter to a position corresponding to t%e fuel flow.
Ilustración 8
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IGNITION SYSTE
0. $%e purpose of t%e engine ignition system is to pro&ide a means of initiating initiating or sustaini sustaining ng com,ust com,ustion ion of t%e fuel-ai fuel-airr mi"ture mi"ture in nine can-annula can-annularr com,ust com,ustion ion c%am,ers in t%e com,ustion section. :0<=I=( I(=I$I= 5>$0(E I E0>K. =$ $HA I(=I$E< P>H( I I(=I$I= I =. =$ $E$ I(=I$I= K$E2 :AE= PE<==E> 0H( < :AE= I=>0220+>E I=>0220+>E 0
+. $%ere are t%ree identical ignition systems/ one for eac% engine. $%e ignition system for eac% engine consists of control switc%es/ an ignition e"citer/ two %ig% tension leads and two igniter plugs. •
Electrical Power upply
0. Ignition Ignition power supply supply $%e #)-4 Boule single pac continuous ignition system is powered ,y two input &oltage at t%e ignition e"citer/ e"citer/ #8 5 and 11' 5/ 4)) AD. $%e single unit %ousing incorporates one power input connection and two output connectors. 0 dual pac system is also a&aila,le. $%e dual pac system %as two e"citers wit% a power input connection for eac% e"citer. $%e two output connections supply t%e %ig% tension &oltage t%roug% t%e e"citer ca,les to t%e igniter plugs. P9: +L'88) installed t%e optional dual pac system.
?a@ Ignition e"citer 1@ $%e #)-4 ignition e"citer is a capacitor disc%arge system designed to pro&ide ignition for t%e $8 $ur,ofan Engine. $%is ignition e"citer ser&es t%e dual purpose of pro&iding intermittent duty starting ignition and continuous duty ignition w%ic% are used as reGuired after starting. $wo different input &oltages are reGuired for t%e e"citer. +ot% circuits of t%e ignition e"citer are contained in one compact %ousing wit% wit% one one input input powe powerr conn connect ectio ion n and and two two outp output ut conne connecti ctions ons.. $%e $%e dual dual pac pac system %as two input power connections and two output power connections. #@ ee ig. for ignition e"citer. 3@ ee ig. for ignition e"citer ta,le of leading particulars. 4@ ee ig. for ignition e"citer wiring sc%ematic.
Ilustración 9
Distri!ution •
Aig% tension distri,ution
?1@ $%e %ig% tension distri,ution system deli&ers %ig% &oltage from t%e ignition e"citer to t%e com,ustion c%am,ers ,y means of %ig% tension leads and igniter plugs. $%e %ig% tension &oltage from t%e e"citer ioniDes t%e gap at t%e plug and t%e result is a spar of &ery %ig% energy capa,le of igniting fuel. ?a@ Aig% tension leads 1@ $%e igniter plug lead assem,lies are installed ,etween t%e ignition e"citer and t%e igniter plugs. $%e lead assem,lies transfer %ig% freGuency/ %ig% &oltage from t%e ignition e"citer to t%e igniter plugs. ?,@ Igniter plugs
1@ $%ere $%ere are are two two ignite igniterr plugs plugs w%ic% w%ic% are mounte mounted d on t%e lower lower front front of t%e t%e com,ustion c%am,er outer case. ne proBects into t%e num,er four com,ustion c%am,er and t%e ot%er proBects into t%e num,er se&en com,ustion c%am,er. •
peration
0. 0ll ground ground starts or inflig%t airstarts s%ould s%ould ,e made wit% t%e use of t%e #)-Boule e"ci e"cite terr ?fir ?firin ing g ,ot% ,ot% igni ignite terr plug plugs@ s@.. or or opti optimu mum m life life of igni igniti tion on syst system em components/ t%e operating duty cycle is # minutes =/ 3 minutes / # minutes =/ and #3 minutes . =$E If t%e #)-4 oule single pac e"citer unit %as ,een operated ,eyond t%e recommended duty cycle/ t%e unit must ,e remo&ed and c%eced per o&er%aul instru instructi ctions ons.. $%e $%e integ integrit rity y of compo componen nents ts wit% wit%in in t%e t%e e"cite e"citerr may %a&e %a&e ,een ,een compromised due to o&er%eating ?
Ilustración 10
. $%e intermittent duty starting circuit reGuires an input of #8 5 nominal w%ile t%e continuous duty circuit reGuires an input of 11' 50 4)) AertD. $%e intermittent duty starting circuit disc%arges t%roug% ,ot% outlets/ firing two igniter plugs. $%e continuous duty circuit disc%arges only t%roug% t%e outlet mared =$I=HH H$K H$>E$/ firing one igniter plug. par gaps pre&ent current from following in one circuit w%en t%e ot%er circuit is in operation. =$E $%e e"citer is repaira,le using test eGuipment a&aila,le in most airline o&er%aul s%ops. Positi&e %ermetic seal is assured t%roug% use of a stainless steel case weldment. $%e $%e e"cite e"citerr capa, capa,ili ility ty for cont continu inuou ous s opera operatio tion n will will assure assure conf conform orman ance ce wit% wit% potential potential airline ignition duty cycles. 2a"imum e"citer ser&ice life can/ %owe&er/ %owe&er/ ,e attaine attained d ,y ignitio ignition n utiliDa utiliDation tion per recommen recommended ded engineC engineCor or airplan airplane e operatio operational nal procedures. . $%e igniter plug pro&ides a gap across w%ic% an electrical spar passes to ignite t%e fuel-air mi"ture. $%e igniter plug gap ,ecomes ioniDed ,y &ery %ig% &oltage ?###6 ;5@ pro&ided ,y a %ig% tension transformer. transformer. nce t%e air gap ,ecomes ioniDed/ current stored in a storage capacitor disc%arges across t%e gap. $%is disc%arge results in a %ig% temperature plasma arc w%ic% is capa,le of igniting t%e fuel-air mi"ture. =$E Pratt and :%itney recommends t%e use of any igniter plug regardless of type/ type/ t%at t%at meets meets t%e o&er%au o&er%aull manual manual e"amina e"amination tion and testing testing reGuire reGuirement ments. s. Aowe&er Aowe&er// eac% eac% operator operator must concern concern %imself wit% determi determining ning %ow long t%e ignite igniterr plug plug can can ,e e"pec e"pecte ted d to cont continu inue e meetin meeting g t%ese t%ese reGu reGuire iremen ments ts w%ile w%ile e"posed to engine use wit%in %is operation. $%e appropriate inspectionCc%ec/ cleaningCpainting cleaningCpainting inter&al inter&al can only ,e esta,lis%ed ,y t%e indi&idual operator ,ased on %is e"perience.
•
E
0. $%e following following engine air systems are installed ,y Pratt and :%itney and comprise part of t%e ,asic engineM anti-icing pro&isions for t%e engine inlet guide &anes and forward compressor case/ deicing system for t%e engine fuel supply/ and cooling and sealing air for t%e engine ,earings.
Ilustración 11
ENGINE ANTI-ICING - DESCRIPTION AND OPERATION OPERATION
0. $%e engine compressor compressor inlet case and inlet guide &anes are pro&ided pro&ided wit% internal passages w%ic% allow t%e circulation of %ot air t%roug% t%e assem,ly. $%e resulting temperature increase will pre&ent ice from accumulating on t%e surface of t%e inlet guide &anes.
+. $%e %ot air supply is e"tracted from t%e eig%t% stage of t%e engine compressor sectio section n and and is contr controll olled ed ,y t%erm t%ermos ostat tatic ic regul regulat ators ors and and s%ut s%utof offf &al&e &al&es. s. $%e $%e switc%es w%ic% control t%e s%utoff &al&es also energiDe energiDe t%e nose cowl anti-icing air &al& &al&es es so t%at t%at ,ot% ot% t%e t%e engin ngine e and t%e t%e cow cowl anti anti-i -ice ce syst system ems s oper operat ate e simultaneously.
Engine 0nti-Icing 0ir 5al&e 5al&e
0. 0n engine anti-icing anti-icing air s%utoff &al&e is pro&ided pro&ided in ,ot% of t%e plum,ing lines w%ic% supply %ot air to t%e inlet guide &anes and inlet guide &ane case. $%e &al&es are located at t%e 1 oFcloc and 11 oFcloc positions aft of t%e inlet guide &ane case. +. Eac% anti-icing air &al&e is motor operated and w%en energiDed dri&es to t%e fully open or closed position as determined ,y t%e control switc% selection. •
Engine 0nti-Icing 0ir
0. 0n air temperature temperature regulator regulator or a fi"ed orifice plate is located on t%e upstream side of eac% antiicing air &al&e. $%e regulators or orifice plates limit t%e &olume of anti-icing anti-icing air supplied to t%e inlet guide &ane assem,ly. $%is $%is eeps t%e guide &ane assem,ly from ,ecoming too %ot pre&enting e"cessi&e temperature of t%e engine inlet air.
Ilustración 12
•
peration
0. $%e engine anti-icing anti-icing system uses %ot air ,leed from t%e engine compressor compressor section to %eat t%e engine inlet guide &ane assem,ly. $%e air supply is controlled ,y s%utoff and temperature regulating orifices. $%e s%utoff &al&es are operated ,y switc%es located on t%e pilotsF o&er%ead panel. +. :%en t%e anti-icing air &al&es are opened %ot air circulates around t%e engine inlet guide &ane assem,ly/ t%e air passes t%roug% eac% inlet guide &ane and into t%e inner s%roud w%ic% forms part of t%e engine front ,earing %u,. $%e air passes from t%e front %u, into t%e engine nose dome/ a slot in t%e nose dome e"%austs t%e air into t%e engine inlet air stream. . $%e &al&e position indicating lig%ts are illuminated w%ene&er a &al&e is in a position corresponding to t%e anti-icing control switc% setting. uring &al&e transit/ t%e &al&e position indicating lig%ts are not illuminated. ENGINE E"AUSTING SYSTE
$%e engine e"%aust system controls t%e direction of t%e engine e"%aust gases. $%e engine e"%aust system %as t%ese su,-systems N $ur,ine e"%aust N $%rust re&erser ?$C<@.
Ilustración 13
$%e engine e"%aust system controls t%e direction of t%e tur,ine e"%aust gases and t%e fan air e"%aust gases. •
$ur,ine E"%aust ystem
$%e tur,ine e"%aust system supplies an e"it for t%e engine e"%aust gases. $%is e"it increases t%e &elocity of t%e e"%aust gases. $%is increases engine t%rust. $%e maBor components of t%e tur,ine e"%aust system are t%e e"%aust noDDle and t%e e"%aust plug. •
$%rust
$%e t%rust re&erser ?$C<@ system c%anges t%e direction of t%e fan air e"%aust to %elp create re&erse t%rust. $%e flig%t crew uses re&erse t%rust to slow t%e airplane after after landi landing ng or durin during g a reBec reBecte ted d taeo taeoff ff ?<$ ?<$@. @. $%e $%e tur,in tur,ine e e"%au e"%aust st airfl airflow ow direction does not c%ange during re&erse t%rust. $%e $C< system %as a electro%ydraulic control system and an indicating system. $%e $C< system %as two t%rust re&ersers. $C< 1 is t%e t%rust re&erser for engine Eac% $C< %as a left and rig%t %alf. Eac% %alf %as a translating slee&e w%ic% mo&es aft ?deploy position@ for re&erse t%rust. $%e two slee&es wor independently from eac% ot%er. an air e"%aust goes out radially and forward w%en t%e translating slee&es are in t%e deploy position. our %inges %inges attac% attac% eac% eac% $C< %alf to t%e strut. strut. Kou must deacti& deacti&ate ate t%e t%rust t%rust re&erser ,efore you open a $C< %alf. >atc%es are at t%e ,ottom of t%e two %al&es. $%e latc%es eep t%e two %al&es toget%er.
Ilustración 14
•
$%rust
$%e t%rust re&erser ?$C<@ system %as t%ese su,systems
$%rust re&erser ontrol Indicating.
$%e $C< system controls t%e direction of engine fan air e"%aust for forward and re&erse t%rust.
$%e $C< system c%anges t%e direction of t%e fan air e"%aust to %elp decrease t%e speed of t%e airplane after landing or during a reBected taeoff ?<$@. $%e $C< system %as two t%rust re&ersers. $C< 1 is t%e t%rust re&erser for engine 1 ?left@. $C< # is t%e t%rust re&erser for engine # ?rig%t@. Eac% $C< %as a left and rig%t %alf. Eac% %alf %as a translating slee&e w%ic% mo&es aft for re&erse t%rust. $%e slee&es wor at t%e same time/ ,ut are independent from eac% ot%er. $%ree %ydraulic actuators mo&e eac% slee&e.
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$C< ontrol ystem
$%e $C< control system lets you deploy t%e $C< w%en t%e airplane is less t%an 1) feet ?3 meters@ from t%e ground. Kou gi&e a deploy signal to t%e control system w%en you raise a re&erse t%rust le&er. Kou supply a stow signal w%en you return t%e re&erse t%rust le&er to t%e stow position. $%e $C< control &al&e module controls %ydraulic power to t%e %ydraulic actuators. $%e re&erse t%rust le&er operates t%e switc%es necessary to send a deploy or stow signal to t%e $C < control &al&e module. $%e sync locs pre&ent t%e operation of t%e %ydraulic actuators w%en t%ere is no deploy signal. $%e primary purpose of t%e engine accessory unit ?E0H@ is to control t%e $C< stow operation. operation. $%e E0H supplies front panel ,uilt-in-test eGuipment ?+I$E@ to %elp you do trou,les%ooting of t%e control system. $%e E0H uses two $C< pro"imity sensors for eac% eac% trans translat lating ing slee& slee&e e for cont control rol.. $%e $%e E0H E0H also also inter interfac faces es wit% wit% t%e t%e $C< $C< indicating system to control t%e
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$C< Indicating ystem
$%e $C< indicating system supplies t%ese indications in t%e flig%t compartment
inear &aria,le differential transformer ?>5$@ data on t%e control display unit ?H@.
$%e common display system ?@ s%ows t%e 5$s w%ic% supply translating slee&e position data to t%e electronic engine control ?EE@. When on, the REVERSER light shows that there is a failure in one of these areas:
$C< control system 2ec%a 2ec%ani nical cal failur failure e ?w%ic ?w%ic% % pre&e pre&ents nts t%e contr control ol syste system m from from corre correct ct operation@.
$%e
Ilustración 15
Ilustración 16
T#RUST RE$ERSER - #YDRAULIC ACTUATORS ACTUATORS AND AND SYNC S#AFTS
$%e %ydraulic actuators mo&e t%e translating slee&es during $C< deploy and stow operations. $%e sync s%afts mae t%e %ydraulic actuators e"tend and retract at t%e same speed. $%e sync s%afts also let you manually operate t%e %ydraulic actuators. Eac% $C< %alf %as t%ree %ydraulic actuators. actuators. $%e actuators e"tend during a deploy operation and retract during a stow operation. Eac% $C< %alf %as one locing actuator and two nonlocing actuators. $%e locing actuator must unloc for t%e ot%er %ydraulic actuators on t%at same %alf to operate.
$%e locing actuators %a&e a position feed,ac mec%anism and a manual unloc le&er. $%e position mec%anism operates a linear &aria,le differential transformer ?>5$@. $%e manual unloc le&er lets you unloc t%e locing actuator for a manual translation of t%e $C< slee&e. There are two sync shafts on each T/R half.
$%e locing actuators are t%e top actuators on eac% $C< %alf. $%e two non-locing actuators are ,elow t%e locing actuators. 0ll actuators actuators attac% attac% to t%e t%e torGue ,o" and to t%e translating translating slee&e. Kou open t%e fan cowl and mo&e t%e translating slee&e aft to get access to t%e %ydraulic actuators. $%e upper sync s%aft is inside t%e deploy %ydraulic tu,e/ ,etween t%e upper and center actuators. $%e lower sync s%aft is inside t%e deploy %ydraulic tu,e/ ,etween t%e center and lower actuators. $%e deploy tu,es are larger t%an t%e stow tu,es. Kou open t%e fan cowl to get access to t%e tu,ing.
Ilustración 17
ENGINE STARTING
$%e engine starting system uses pneumatic power to turn t%e engineFs =# rotor during a start or motor procedure. Pneumatic power comes from one of t%ese sources
0PH Pneumatic ground eGuipment pposite engine.
$%ese components control t%e engine start system
lig%t compartment switc%es isplay electronics unit ?EH@ Electronic engine control ?EE@.
$%e engine starting system operates on t%e ground and in flig%t.
Ilustración 18
$%e $%e engin ngine e star starti ting ng syst system em uses uses t%es t%ese e airp airpla lane ne and and engi engine ne syst system ems s or components
Pneumatic power Electrical power lig%t compartment switc%es Engine fuel control system Engine control system. ommon display system ?@.
Engine tart witc% Kou put t%e engine start switc% to t%e (< position to turn t%e engine wit% t%e starter. $%e switc% automatically mo&es to t%e position at starter cutout. :%en electrical and pneumatic power is a&aila,le/ t%is %appens w%en you put t%e switc% to t%e (< position •
Electronic engine control ?EE@ recei&es a start signal 0PH recei&es recei&es an engine start start signal signal tart &al&e opens and t%e pneumatic starter turns t%e engine.
$%e crew uses t%e >$ position to start t%e engine in flig%t w%en t%e starter is not necessary. $%e =$ position supplies continuous ignition •
tart 5al&e and tarter
$%e start &al&e opens to supply power to t%e starter. Hsually/ t%is &al&e opens w%en you put t%e engine start switc% to t%e (< position. $%e start &al&e position s%ows on t%e engine display. Kou can manually open t%e &al&e. $%e starter turns t%e engine =# rotor t%roug% t%e engine accessory gear,o" ?0(+@. •
EE
$%e EE protects t%e engine during start. $%e EE s%uts off fuel supply to t%e engine w%en it finds t%e engine parameters are out of limits during a start. •
isplay Electronics Hnits ?EHs@
$%e EHs are components of t%e common display system ?@. $%e EHs monitor =# and let t%e engine start switc% go ,ac to t%e position at starter cutout.
Ilustración 19
GENERATOR COOLING - DESCRIPTION AND OPERATION
0. $%e generator generator is a %ig% %ig% speed unit t%at reGuires cooling w%ene&er w%ene&er it is operating. operating. $o pro&ide t%is cooling t%e generator is supplied wit% engine ,leed air. 0 port on t%e outer fan case of t%e engine is connected ,y a large duct/ to a fitting on t%e end of t%e generator. 0n e"%aust duct/ attac%ed to t%e generator s%roud/ mates wit% t%e cooling air e"%aust port in t%e engine cowl panel.
+. :%en an engine is operating/ low pressure fan air is forced t%roug% t%e large duct into t%e generator. $%e air circulates around t%e inside of t%e generator t%en lea&es t%roug% t%e screened openings around t%e forward end of t%e generator casing. 0fter lea&ing t%e generator/ t%e air enters t%e generator s%roud/ passes t%roug% t%e e"%aust duct and is t%en e"%austed o&er,oard t%roug% t%e e"%aust port in t%e engine cowl panel.
Ilustración 20
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I> >I=( - E
0. Eac% is cooled ,y t%e oil w%ic% acts as a lu,ricant lu,ricant for t%e unit and as a %ydraulic media in transmission. $%is oil is cooled in a cooler t%at uses air as t%e cooling agent. uring normal flig%t ram air is forced t%roug% t%e coolers to e"tract t%e %eat from t%e oil. 0t low flying speeds t%is ram air may not ,e sufficient sufficient to cool t%e oil adeGuately/ and on t%e ground no ram air is a&aila,le. $o pro&ide sufficient cooling under t%ese conditions/ engine ,leed air is used to induce air flow t%roug% t%e coolers. +. $%e oil cooling system comprises an air inlet duct/ an oil cooler/ an e"%aust duct/ an eBector noDDle and an oil cooler s%utoff &al&e. Eac% engine %as a air scoop w%ic% directs ram air into t%e air inlet duct. $%e air scoops for engines =o. 1 and 3 are located in t%e lower portion of t%e engine nose cowl. $%e engine =o. # air inlet is situated in t%e lower portion of t%e engine inlet duct. $%e air inlet duct connects to t%e oil cooler/ located on t%e lower forward portion of t%e engine/ and t%e e"%aust duct connects t%e aft side of t%e oil cooler to t%e air e"%aust port in t%e engine cowl panels. $%e air eBector noDDle is mounted in t%e e"%aust duct and is connected to t%e t%irteent% stage engine ,leed air duct ,y
tu,ing into w%ic% t%e oil cooler s%utoff &al&e is installed. $%e &al&e is located on t%e upper portion of t%e forward fan case on t%e rig%t side of t%e engine. . :%en t%e system is energiDed and t%e oil cooler control switc% is in t%e correct position/ t%e oil cooler s%utoff &al&es will open and allow engine ,leed air to flow t%roug% t%e eBector noDDles. 0irflow will ,e induced in t%e oil cooler to pro&ide cooling for t%e oil flowing t%roug% t%e coolers.
Ilustración 21
ENGINE CONTROL SYSTE - DESCRIPTION AND OPERA OPER ATION
0. 0 manually-operated manually-operated control system for eac% engine pro&ides separate control of engine starting and t%rust. tarting of eac% engine is accomplis%ed ,y use of a single le&er to energiDe t%e ignition system and to initiate fuel flow to t%e engine. 0not%er le&er assem,ly assem,ly controls ,ot% forward and re&erse re&erse t%rust ,y regulating fuel flow flow and and actu actuat atin ing g t%e t%e t%ru t%rust st re&e re&ers rser er.. 0n inte interl rloc oc mec% mec%an anis ism m pre& pre&en ents ts simultaneous actuation of forward and re&erse t%rust le&ers for eac% engine. +. $%e engine control system consists of an engine start le&er and a t%rust le&er assem,ly for eac% engine/ connected ,y a series of t%rottle control ca,les and mec%anical linages to t%e fuel control units on t%e engines ?ig. 1@. 0 t%rust le&er friction friction regulator regulator applies applies a ,raing ,raing force force to all t%rust t%rust le&er le&er assem,lie assem,lies s during during forward t%rust operation.
. 0 drum-and-s drum-and-s%aft %aft assem,ly assem,ly for eac% eac% engine engine transmi transmits ts engine engine control control ca,le ca,le tra&el to t%e upper t%rust and start rods. 0 stop lug on t%e start ca,le drum pro&ides a mec%anical stop against t%e support ,racet w%en t%e start le&er is at H$. n engines =os. 1 and 3/ t%e engine control drum-and-s%aft assem,ly is in t%e nacelle strut. n engine num,er #/ t%e assem,ly is mounted on a ,racet attac%ed to t%e aft side of t%e engine firewall. . Eac% engine start le&er is connected ,y ca,les to t%e drum-and-s%aft assem,ly. >inage rods connect a cran on t%e start s%aft to a cran on t%e engine crosss%aft and from a cran on t%e rig%t end of t%e cross-s%aft to a le&er on t%e fuel control unit. E. $%e $%e t%rust t%rust le&er le&er assem, assem,ly ly is conn connect ected ed ,y ca,le ca,les s to t%e t%e drum-a drum-and nd-s% -s%aft aft assem,ly. 0 rod connects a cran on t%e t%rust s%aft to a cran on t%e engine cross-s%aft. 0 cran and lining rod on t%e rig%t end of t%e engine cross-s%aft connects to t%e power control s%aft on t%e fuel control unit. . 0ctuation 0ctuation of t%e t%rust le&er assem,ly regulates fuel flow in t%e fuel control unit. or re&ersen t%rust/ t%e le&er assem,ly mo&ement actuates t%e t%rust re&erser in addition to increasing fuel flow. It s%ould ,e noted t%at t%e direction of tra&el of t%e t%rust control ca,les and drums is t%e same for decreasing forward t%rust as it is for increasing re&erse t%rust. $wo distinct increases in le&er loads are encountered as t%e le&er is mo&ed in t%e direction of increasing re&erse t%rust. $%e first increase occurs w%en a spring-loaded roller engages a detent ?ma"imum power detent@. $%e second increase occurs at t%e point of engagement of a spring ?re&erse t%rust feel control/ if installed@.
Ilustración 22
Ilustración 23
ENGINE INDICATING INDICATING - DESCRIPTION
0. $%e engine indicating indicating systems descri,ed descri,ed in t%is c%apter include t%e engine pressure pressure ratio ?EP<@ ?EP<@ indicat indicating ing system/ system/ a tac%omet tac%ometer er system system to measure measure t%e speed of t%e low pressure compressor ?=1@ and %ig% pressure compressor ?=#@/ an e"%aust gas temperature ?E($@ indicating system/ and an air,orne &i,ration monitoring system. +. Eac% system pro&ides a reading of engine operating conditions on indicators located in t%e control ca,in. $%is information ena,les t%e monitoring of engine output and maintaining a selected flig%t performance. . 7#7-#)) eries 0irplanes %a&e engine failure warning lig%ts located on t%e lig%ts%ield. $%e lig%ts are controlled ,y pressure switc%es in t%e engine ,leed system and pro&ide &isual warning in t%e e&ent of engine t%rust loss ?
E=(I=E P
0. $%e engine pressure pressure ratio ?EP<@ indicating indicating system s%ows t%e engine power output and is used for setting engine t%rust and for monitoring engine performance. $%e EP< indicating system consists of one inlet pressure ?Pt#@ sensing pro,e/ si" e"%aust pressure pressure ?Pt7@ sensing pro,es/ an engine pressure ratio transmitter transmitter and a pressure ratio indicator for eac% engine. +. $%e $%e engine engine inlet inlet and and e"%a e"%aust ust pres pressur sures/ es/ sense sensed d ,y t%e press pressure ure sensi sensing ng pro,es/ are transmitted to t%e pressure ratio transmitter. $%e transmitter con&erts t%e e"%aust and inlet pressures pressures into a ratio/ pro&ides output signals proportional to
t%e EP< and and trans transmit mits s t%e t%e signa signals ls to t%e EP< indic indicat ator or locat located ed in t%e t%e flig% flig%tt compartment. $%e indicator transforms t%e electrical input signals into t%e indicator pointer s%aft rotation and digital t%ree-w%eel counter to s%ow t%e engine pressure ratio. 0 test receptacle/ used to attac% a master indicator/ is included in t%e circuit to pro&ide a means of adBusting and c%ecing t%e system ?ig. 1@. n airplanes incorp incorpora oratin ting g EP
Inlet Pressure ensing Pro,e
0. $%e engine engine inlet pressure pressure ?Pt#@ is sensed sensed ,y a pro,e similar to a pitot tu,e. $%is $%is pro,e is mounted t%roug% t%e center of t%e nose dome wit% t%e open end of t%e tu,e facing t%e inlet air stream. $%e &ent %ole in t%e pro,e functions as t%e pro,e ice detector detector ,y decreas decreasing ing engine engine inlet inlet pressure pressure ?increasing ?increasing EP<@ w%en w%en icing icing occurs. $%e pro,e is anti-iced ,y t%e engine anti-ice system. •
E"%aust Pressure ensing Pro,e
0. Eac% engine %as si" e"%aust ?disc%arge/ ?disc%arge/ Pt7@ pressure sensing pro,es proBected proBected into t%e stream of tur,ine e"%aust gases. gases. $%e pro,es are connected connected to a common manifold for o,taining an a&erage pressure of t%e e"%aust gases. E"terior connection to t%e manifold is made at a single point t%roug% t%e fan disc%arge outer duct at appro"imately t%e 7 oFcloc position.
Ilustración 24
T#RUST RE$ERSER - DESCRIPTION AND OPERATION OPERATION
0. 0 t%rust re&erser unit/ located on t%e aft end of eac% engine/ is used to reduce t%e lengt% of t%e landing roll. $%e t%rust re&erser is of t%e clams%ell door type/ pro&i pro&idi ding ng t%rus t%rustt re&ers re&ersal al ,y ,loc ,locing ing t%e t%e engin engine e e"%a e"%aust ust gas gas flow flow pat% pat% wit% wit%
clams%ell doors and deflecting t%e gases t%roug% openings in t%e re&erser frame onto two e"ternal deflector doors or t%roug% t%e cascade &ane deflectors w%ic% furt%er furt%er deflect deflect t%e gas forward forward and o&er,oa o&er,oard. rd. Eac% Eac% t%rust t%rust re&erse re&erserr operates operates independently. $%e maBor components of t%e t%rust re&erser are t%e t%rust re&erser frame assem,ly/ two a"ially-mounted clams%ell doors/ two %inge installations for t%e clams%ell doors/ two deflector doors/ or cascade &ane deflectors/ two t%rust re&erser actuators/ a seGuence &al&e on re&ersers wit% deflector doors/ and a t%rust re&erser locout actuator or loc mec%anism as applica,le. $%e tailpipe is attac%ed to t%e t%rust re&erser unit and is considered considered as part of t%e t%rust re&erser assem,ly. 0 t%rust re&erser s%roud assem,ly installed around t%e circumference of t%e t%rust re&erser forward mounting ring acts as a gas seal ,etween t%e engine and t%e t%rust re&erser. +. $%e t%rust re&erser on t%e center engine ?engine =o. #@ is t%e same as t%e t%rust re&ersers on t%e strut-mounted engines engines ?engines 1 and 3@ e"cept for certain installation features. $%e center engine t%rust re&erser is mounted so t%at t%e e"%aust gases are deflected out t%e sides of t%e t%rust re&erser or aft fuselage since t%e t%rust re&erser forms t%e aft end of t%e fuselage. $%e strut-mounted t%rust re&erser installations are oriented to deflect e"%aust gases a,o&e and ,elow t%e engine/ resulting in t%e center engine re&erser installation ,eing rotated !) degre degrees es wit% wit% respe respect ct to t%e strutstrut-mou mount nted ed re&e re&erse rsers. rs. 0lso/ lso/ a dou, dou,lele-fla flang nged ed adapter ring or spacer tapered from ,ottom to top is installed ,etween t%e aft end of t%e engine and t%e forward end of t%e t%rust re&erser on engines 1 and 3 to direct t%e e"%aust gases for t%e proper t%rust angle. Engine =o. 3 t%rust re&erser installation is rotated 18) degrees from engine =o. 1 installation to mae t%e installations compati,le wit% t%e t%rust re&erser pneumatic tu,ing installations on t%e respecti&e engines.
. $%e t%rust re&erser is pneumatically actuated and control is pro&ided ,y a re&erse t%rust le&er ?one for eac% engine@ on t%e pilotFs control stand. Pressure is suppl supplied ied ,y engine engine 13t%-s 13t%-sta tage ge ,leed ,leed air air sourc source e ?Ps4@ ?Ps4@.. $%e $%e t%rus t%rustt re&ers re&erser er pneumatic pneumatic plum,ing plum,ing taps into a 13t%-st 13t%-stage age air distri,u distri,ution tion line located located on t%e engine ?center engine@ and in t%e strut ?side engines@. $%e pneumatic supply line routes air to a t%rust re&erser directional &al&e w%ic% is mounted to t%e engine control s%aft ,racet underneat% t%e forward end of t%e engine on t%e center engine and in t%e strut on t%e side engines. $%rust le&er input is transmitted to t%e engine engine control controls s s%aft s%aft installa installation tion ,y direct direct ca,le ca,le connect connection. ion. 0 t%rust t%rust re&erse re&erser r control cam on t%e lower end of t%e s%aft pro&ides position input for t%e directional directional &al&e. 0ir is routed from t%e directional &al&e ,y t%e pneumatic plum,ing to two t%rust re&erser actuators pro&iding t%e input to t%e t%rust re&erser for cruise and re&erse re&erse t%rust t%rust actuatio actuation n and operati operation. on. $%e t%rust t%rust re&erse re&erserr locout locout actuato actuator/ r/ located upstream of t%e t%rust re&erser actuators in t%e re&erse t%rust pneumatic line/ maintains t%e t%rust re&erser mec%anically loced in forward t%rust position until re&erse t%rust is selected. :%en re&erse t%rust is selected t%e actuator is pneumatically operated to unloc t%e re&erser and route air to t%e t%rust re&erser actuators for re&erse t%rust operation. $%e seGuence &al&e is installed only on
re&ersers wit% deflector doors and is located upstream of t%e actuators in t%e forward t%rust pneumatic line to route air seGuentially to t%e clams%ell door piston and t%e deflector door piston of t%e actuators to retract t%e clams%ell doors to t%e forward t%rust position ,efore retracting t%e deflector doors. 0 pus%-pull control follow-up system running ,etween t%e t%rust re&erser clams%ell %inge arm and a follow up cam in t%e t%rust control mec%anism limits t%rust control motion w%ile re&erser is in transit or is not in commanded position. .
$%rust
0. $%e t%rust re&erser re&erser frame is a welded structure to w%ic% t%e clams%ell doors/ deflector deflector doors or cascade &ane deflectors/ clams%ell and deflector door actuating actuating linage/ if installed/ t%rust re&erser actuators/ seGuence &al&e/ and tailpipe are attac%ed. Ainge support assem,lies are installed t%roug% t%e upper and lower &ertical centerlines of t%e frame pro&iding attac%ment for t%e clams%ell door %inge assem,lies.
Ilustración 25
ENGINE OIL SYSTE - DESCRIPTION AND OPERA OPER ATION
0. $%e engine oil system comprises an oil storage and an oil distri,ution distri,ution system toget%er wit% t%e necessary indicating systems w%ic% pro&ide measurements of oil Guantity/ oil pressure and oil temperature. 0 low oil pressure and filter ,ypass indicating system is also pro&ided. +. Eac% engine is pro&ided pro&ided wit% an independent oil system w%ic% pro&ides cooling and lu,rication of engine gears and ,earings. 0n oil storage tan/ mounted on t%e lower left side of t%e engine/ furnis%es a continuous supply of oil to t%e engine dri&en oil pressure pump in t%e accessory dri&e gear,o" %ousing. 0n e"ternal line carries oil from t%e pump to a full flow type fuelCoil cooler. ooled oil is t%en deli&er deli&ered ed to t%e engine engine ,earing ,earings s t%roug% t%roug% a distri,u distri,ution tion manifol manifold d and galleri galleries es formed in t%e engine structure. . 0n oil filter is pro&ided downstream of t%e oil pump. $%e filter %ousing is made integral wit% t%e accessory dri&e gear,o" casing. 0 remo&a,le co&er is located on t%e outside of t%e gear,o" to allow replacement or cleaning of t%e filter core. 0 ,ypass &al&e is arranged ,etween t%e inlet and outlet of t%e filter. If t%e filter ,ecomes clogged t%is &al&e will open and allow a flow of unfiltered oil to circulate in t%e engine. . il is sca&enged sca&enged from t%e engine ,earing ca&ities ,y t%ree pumps and returned to t%e accessory dri&e gear,o". rom t%ere it is pumped ,ac into t%e engine oil tan.
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0. Eac% engine is pro&ided pro&ided wit% a cylindrical s%aped oil tan w%ic% mounts on t%e left front face of t%e accessory dri&e gear,o" and is secured at t%e front ,y a strap. :it% t%e engines installed on t%e airplane/ t%e tan %olds appro"imately fi&e H.. gall gallon ons. s. $%e $%e rema remain inin ing g tan tan &olu &olume me acco accomm mmod odat ates es any any oil oil foam foamin ing g and and e"pansion. =$E ince t%e =. 1 and =. 3 engines are installed in a slig%tly nose %ig% attitude/ t%e oil tans on t%ese engines will %old less oil t%an t%e tan on =. # engine. +. $%e tan is constructed of stainless steel and is capa,le of wit%standing/ wit%out permanent deformation/ t%e stresses imposed ,y pressure/ &i,ration/ and s%oc loads suc% as may occur during landing/ roug% flig%t conditions/ etc. 0 ,affle ser&es to minimiDe slos%ing of t%e oil in t%e tan. 0 deaerator in t%e tan separates most of t%e air from t%e returning oil/ t%us minimiDing foaming. . er&icing of t%e oil tan is accomplis%ed t%roug% a filler port/ located in t%e oil tan sump ca&ity. 0ny oil t%at is spilled in t%e sump ca&ity is drained to a fluid drain tan on t%e underside of t%e engine. . or ground c%ec of oil Guantity/ a dipstic is attac%ed to t%e self-locing filler cap. 0 capacitance sensing pro,e in t%e tan transmits an electrical signal for remote indication of oil Guantity during flig%t. E. $%e tan is eGuipped wit% an inlet strainer at t%e filler port. 0n outlet strainer is located at t%e drain &al&e on t%e underside of t%e tan.
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0. $%e oil tan drain &al&e is located at t%e ,ottom of t%e oil tan. $%e %andle is springloaded springloaded to t%e &al&e closed position. 2anually 2anually rotating t%e %andle !) degrees in a clocwise direction opens t%e &al&e allowing t%e oil to drain from t%e tan. $%e %and %andle le is loc loced ed in t%e t%e &al& &al&e e open open posi positi tion on ,y a ,all ,all dete detent nt arra arrang ngem emen ent. t. ounterclocwise mo&ement of t%e %andle unseats t%e ,alls from t%e detents and allows t%e spring tension to return t%e %andle to t%e &al&e closed position.
Ilustración 26
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0. $%e engine oil distri,ution distri,ution system is a self-contained self-contained %ig% pressure design consisting of a pressure system w%ic% supplies lu,rication to t%e main engine ,earings and to t%e accessory dri&es/ and a sca&enge system ,y w%ic% oil is wit%drawn from t%e ,earing compartments/ and from t%e accessories/ and t%en returne returned d to t%e oil tan. tan. 0 ,reat%er ,reat%er system system connect connecting ing t%e indi&id indi&idual ual ,earing ,earing compartments/ t%e accessory dri&e gear,o"/ and t%e oil tan completes t%e oil distri,ution system. or a complete description of t%e internal engine oil system refer to 7#-))/ P9:0 $8 2aintenance 2anual. •
il Pressure ystem
0. il flows ,y gra&ity from t%e oil tan to t%e engine dri&en pump/ located inside t%e accessory dri&e gear,o" %ousing. Pressure oil from t%e pump flows t%roug% an oil filter to a fuel cooled oil cooler. rom t%is unit it passes to t%e &arious engine ,earings. +ypass &al&es are pro&ided in t%e filter and in t%e oil cooler. $%ese &al&es open and allow oil to continue flowing t%roug% t%e system in t%e e&ent t%at eit%er unit ,ecomes clogged. 0n adBusta,le pressure regulating &al&e/ installed in t%e accessory dri&e gear,o" on t%e pressure side of t%e pump/ maintains system pressure and flow ,y ,ypassing oil ,ac to t%e pump inlet. •
ca&enge il ystem
0. our sca&enge sca&enge pumps return oil from t%e ,earing ca&ities to a sump in t%e accessory dri&e gear,o". $%e sca&enge stage of t%e engine dri&en pump t%en
returns t%e oil to t%e tan. 0 deaerator in t%e tan separates t%e air from t%e returning oil/ t%us minimiDing foaming. •
il +reat%er ystem
0. 0n 0n oil ,reat%er ,reat%er system system connects connects t%e engine engine ,earing ,earing ca&ities/ ca&ities/ t%e accesso accessory ry dri&e gear, gear,o" o"// and and t%e t%e oil oil storag storage e tan. tan. $%is $%is syste system m contr controls ols t%e press pressure ures s in t%e accessory accessory dri&e gear,o" and main ,earing ca&ities/ t%ere,y ensuring adeGuate oil flow and pre&enting sca&enge pump ca&itation during engine operation. +. il droplets and &apor are remo&ed from t%e ,reat%er ,reat%er airstream ,y a centrifugal centrifugal separ separato atorr locat located ed in t%e acces accesso sory ry dri&e dri&e gear gear,o" ,o".. 0fter fter passi passing ng t%rou t%roug% g% t%e separator unit t%e ,reat%er air is e"%austed o&er,oard t%roug% a &ent pipe. •
P9:0 P9:0E= E=(I (I=E =E I> I> I$ I$
0. $%e engine oil distri,ution distri,ution system is a self-contained self-contained %ig% pressure design consisting of a pressure system w%ic% supplies lu,rication to t%e main engine ,earings and to t%e accessory dri&es/ and a sca&enge system ,y w%ic% oil is wit%drawn from t%e ,earing compartments/ and from t%e accessories/ and t%en returne returned d to t%e oil tan. tan. 0 ,reat%er ,reat%er system system connect connecting ing t%e indi&id indi&idual ual ,earing ,earing compartments/ t%e accessory dri&e gear,o"/ and t%e oil tan completes t%e oil distri,ution system. or a complete description of t%e internal engine oil system refer to 7#-))/ P9:0 $8 2aintenance 2anual. •
il Pressure ystem
0. il flows ,y gra&ity from t%e oil tan to t%e engine dri&en pump/ located inside t%e accessory dri&e gear,o" %ousing. Pressure oil from t%e pump flows t%roug% an oil filter to a fuel cooled oil cooler. rom t%is unit it passes to t%e &arious engine ,earings. +ypass &al&es are pro&ided in t%e filter and in t%e oil cooler. $%ese &al&es open and allow oil to continue flowing t%roug% t%e system in t%e e&ent t%at eit%er unit ,ecomes clogged. 0n adBusta,le pressure regulating &al&e/ installed in t%e accessory dri&e gear,o" on t%e pressure side of t%e pump/ maintains system pressure and flow ,y ,ypassing oil ,ac to t%e pump inlet. •
ca&enge il ystem
0. our sca&enge sca&enge pumps return oil from t%e ,earing ca&ities to a sump in t%e accessory dri&e gear,o". $%e sca&enge stage of t%e engine dri&en pump t%en returns t%e oil to t%e tan. 0 deaerator in t%e tan separates t%e air from t%e returning oil/ t%us minimiDing foaming. •
il +reat%er ystem
0. 0n 0n oil ,reat%er ,reat%er system system connects connects t%e engine engine ,earing ,earing ca&ities/ ca&ities/ t%e accesso accessory ry dri&e gear, gear,o" o"// and and t%e t%e oil oil storag storage e tan. tan. $%is $%is syste system m contr controls ols t%e press pressure ures s in t%e accessory accessory dri&e gear,o" and main ,earing ca&ities/ t%ere,y ensuring adeGuate oil flow and pre&enting sca&enge pump ca&itation during engine operation. +. il droplets and &apor are remo&ed from t%e ,reat%er ,reat%er airstream ,y a centrifugal centrifugal separ separato atorr locat located ed in t%e acces accesso sory ry dri&e dri&e gear gear,o" ,o".. 0fter fter passi passing ng t%rou t%roug% g% t%e separator unit t%e ,reat%er air is e"%austed o&er,oard t%roug% a &ent pipe.
PNEUATIC STARTING SYSTE - DESCRIPTION AND OPERATION
0. $%e pneumatic pneumatic starting system pro&ides pro&ides means for rotating t%e engines to t%e rpm rpm range range at w%ic% w%ic% starti starting ng can can ,e acco accompl mplis% is%ed ed w%en w%en fuel fuel and and ignit ignition ion are are supplied. +. $%e system consists of t%ree pneumatic starters/ t%ree starter &al&es/ and t%e associated %ardware. or component location. $%e pneumatic starting system is controlled ,y ?1@ tart switc%es/ located on t%e pilotsF o&er%ead panel. ?#@ 0ir conditioning switc%es/ located on t%e t%ird crewmanFs upper panel. ?3@ tart le&ers on t%e pilotsF control stand. . :it% air pressure in t%e pneumatic manifold/ actuating t%e engine start switc% will supply electrical power to open t%e starter &al&e. >ow pressure air acts on t%e tur,ine ,lades of t%e pneumatic starter causing it to rotate.
$%e $%e pneuma pneumatic tic starti starting ng syste system m can can utiliD utiliDe e low pressu pressure re air from from t%ree t%ree separate sources
. =ormally =ormally// t%e engines engines are started started wit% wit% ,leed ,leed air from t%e au"iliary au"iliary power power unit ?0PH@. econdly/ t%e low pressure air can ,e o,tained from a ground source t%roug% t%e pneumatic ground ser&ice connection. $%e cross-,leed air from an operating engine is t%e t%ird source of low pressure air for starting t%e remaining engines. Aowe&er/ t%e cross-,leed starting is not desira,le ,ecause t%e operating engine must operate at appro"imately 8)O power setting to de&elop adeGuate air pressure for starting anot%er engine.
Ilustración 27
Pneu%&tic St&rter
0. $%e pneumatic starter is a lig%tweig%t lig%tweig%t tur,ine-type air motor w%ic% con&erts t%e inetic energy of compressed air into starting torGue sufficient to accelerate t%e engine to starting speed. >ow pressure air and electrical power are reGuired for starter operation. $%e starter will continue to assist t%e engine until starter cutout speed is attained. +. $%e $%e starte starterr consi consist sts s of a scroll scroll asse assem,l m,ly y/ tur,in tur,ine e w%ee w%eel/ l/ redu reducti ction on gear gear assem,ly/ engaging mec%anism/ and an output s%aft. $%e starter is fitted wit% a s%utoff &al&e &al&e to control t%e inlet air flow. :%en t%e &al&e is open it admits air to t%e inlet connection on t%e starter scroll assem,lyM t%e air t%en passes t%roug% t%e starter &anes of t%e scroll assem,ly and is directed radially inward t%roug% t%e tur,ine w%eel imparting %ig%-speed rotation. E"%aust air from t%e tur,ine w%eel t%en passes t%roug% t%e &endor air outlet screen or t%roug% t%e tur,ine w%eel containment assem,ly. . $%e reduction gear train translates t%e %ig% speed/ low torGue of t%e tur,ine w%eel into low speed/ %ig% torGue. $%is output is transmitted t%roug% a pawl and ratc%et engagement mec%anism to t%e output s%aft. rom t%e starter output s%aft t%e craning torGue is transmitted to t%e =# compressor ,y way of t%e accessory dri&e gears. 0 clutc% mec%anism pro&ides engagement of t%e reduction gear train wit% t%e output s%aft for engine startingM w%en t%e speed of t%e output s%aft e"ceeds t%e speed of t%e internal gear %u,/ t%e clutc% mec%anism o&erruns/ t%us pro&iding automatic disengagement. $ur,ine o&erspeed control is maintained ,y t%e cutout switc% mec%anism/ w%ic% automatically closes t%e s%utoff &al&e w%en t%e output s%aft reac%es t%e predetermined cutout speed. $%is safety switc% is mounted on t%e output s%aft and is actuated ,y centrifugal force. $%e pneumatic starter is mounted on t%e accessory dri&e gear case ,eneat% t%e engine.
Ilustración 28
Bibliographic:
0ircraft 2aintenance 2aintenance 2anual 2anual $8 0&iacsa Information Information
