chinook familiarization manual

8/22/2019 Chinook Familiarization Manual

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NOTICE[

This is not on official Department of Army publication. The

l:nformation contained herein is for reference only and offi-

cial approval is not to be implied. Where this information

or any interpretation thereof appears to be in conflict with

an official publication, the latter shall be followed. This

publication will not be revised. II

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FOREWORD

This manual has been prepared to supplement

Boeing- Ver to l cus tomer t ra ining on the CH-47

Helicopter . I t contains a genera l in t roduct ion

to th e entire aircraf t via bas ic desc r ip t ions of

the indiv idual sys tems an d subsys tems .

Informat ion is presen ted in a manner which

wil l enhance the speci f ic da ta found in the ap-

pl icable CH-47 t echnica l manua l s by providing

the foundat ion on which subsequent knowledge

will be built.

Text data pertaining to the CH-47B model is presented

in bold printing.

I l lustra ted data perta in ing to the CH-47B

model is pres ented in red .

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IDEa... --...==}) FAMILIARIZATION MANUAL

r ]1 TABLE OF CONTENTS

SECTION PAGE SECTION PAGE( \

The CH-47 Hel icop te r . . • . • • • • • . • . • • • . • • • 3 Rotary- Wing Blades (Droop Snoot) . . • • • • • • 41

I J) Airfram.e " . . " " " . . . 7 Flight Contro ls . • • • . • . • • . • • . • . . . • . • • • • •• 43

Landing Gear. . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Stabi l i ty Augmenta t ion Sys tem. . • • • • • • • • • . 47

Genera l Ar r a nge me n t . . • . • • • . • • • • . . . . . •• 11 Speed Tr im S y s t e m . • • • • • • • • • . . • • • • • • • • . 51

53owerplant " . . " "" ". . . . . . . . . . . . . 13 Flight Control Hydraul ic Sys tem. • • • . • • . ..1 Fuel System . . ".. " " . . . . 15 Flight Pr inc ip l e s . • • • • • • • . • • • • • . • • • • • . • . 54

P o w e r p la n t C o n tr o l S y s t e m . . • • • • • . • • • . •• 17 Hinge Points" . "". " ... """""". """"""" ." 55

Engine Sta r t and Ignition. • • • . • . . • • • • • • . •• 19 Control Act ions . • • • • • • • • . • • • • • . • • • • • •• 55 IIIAnti-Icing Systems ••.•.••.••.•••••.••••• 21 Control St ick . • • • • • . • • . • • • • • • • • . . • • • •• 56

Fi re Detect ion and Ext inguishing Thrust Control" """""""""""". ". """"""" 56

J) SysteD1.S" •••. " •• " •• " " ••.••.••• " ••••. ". 23 Direc t iona l Cont r o l . • . . • • . • • . • • . • • • • •• 57

Auxil iary Power Unit.................... 25 Automat ic Speed Tr i m. • . • . • . • • . • • • • . • . 57

Powertrain. . "" ".... "... "". ". ".... "". ". . 27 Utility Hydraul ic Sys tem. • . . • • • • . • • . • • . •• 59

)1 Engine and Combining Tr a n s m i s s ions • . • .. 29 Util i ty Hydraul ic Subsystems. • . • • • . • • • • . • 61

F o r w a r d and Aft Transmiss ions . • • . • • • • . . 31 AC-DC Elec t r ica l Sys tems . • • • • • • • • . • . • •• 65

Tr a n s m i s s i o n Lubr icat ion .••..•••••.•..• 33 Cockpit Arrangement •••.•...••••.•• ..•• 67

)) Rotary - Wing H e a d s . • . • • . • . . • • • . . • • • • • • . 35 H e at in g a n d Venti lat ion Sys tem. • . • • • . • • •• 69

Rotary- Wing Contro ls . . • • . . • • • • • • • • • . • •• 37 Cargo/Rescue 71Rota ry - Wing Blades . • • • . . . . . • • . . . • • . • . •• 39 A r m e d CH-47 ..•.••.••...•.•.•••••.•••. 73

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I

}) - ~AMILIARIZATION MANUAL.

)1

THE CH-47 HELICOPTER

In Sep tember 1958, following a design com

petit ion, a mil i t a ry se lec t ion board r ecom

mended tha t Verto l be se lec ted to develop aJ)

new medium t r anspo r t hel icopter for th e Army.

By May 1959, specif icat ions were approved and

a con t rac t i s sued . Now designated th e CH-47 A,

t h e ' Chinook" design and tes t ing proceeded and

the f i rs t f l ight took place in September 1961.

j\The "Ch inook" i s a twin- turbine-engine,

t andem-rotor a i r c r a f t designed fo r transport ing

cargo , t roops and weapons dur ing all weather ,j)visual , or i ns t rument condi t ions . Powered by

twin Lycoming T 5 5 - L - 5 or T55-L-7 engines ,

the CH-47 A develops 2,650 shaf t hor s epower

and cru i ses a t a norma l speed of 13 0 knots a t

a maximum gross weight of 33,000 pounds .

Rotor blades uti l ize a symmet r i ca l airfo i l .)l

A hydraul ica l ly boosted f l ight control sys

t em, supplemented by the Stabi l i ty Augmenta

tion Sys tem (SAS) provides the hel icopter with

f l ight charac ter i s t i cs s imi l ar to a fixed-wing

a i rc ra f t .)1

A r e a r r a m p permi t s rap id s t ra ight - in load

ing and unloading of t roops , vehicles, and cargo.

li

A l6 ,000-pound capaci ty stowable cargo hook

an d a 3,000-pound capaci ty ca rgo - re scue winch

a re also provided. The a i r c ra f t has l if ted a

useful bulk cargo load of 10-1/2 tons.

The crew of th e Chinook consis ts of a pilot ,

copilot , and crew chief. The a i rc ra f t accom.

m.odates ei ther 44 com.bat-equipped t roops or

24 pat ients using pole- type l i t ters .

This ver sa t i le t ranspor t was designed with a

m.inim.um. of m.aintenance requirernents to be

independent of elabora te ground suppor t equip

m.ent. An ins ta l led auxi l iary power uni t (APU)

perm.i ts ground opera t ion of all util i ty system.s

without the need fo r external powe r sources .

The CH-47B model in current production is powered bytwin T55-L-7C Lycoming engines which develop 2,850

shaft horsepower. Maximum gross weight ha s been in

creased to 40,000 pounds and speed capabilities have

been improved with th e addition of a nonsymmetrical air

foil rotor blade destgn and several minor system and fuse

lage modifications. This pertinen t "B " model data ap

pears under the appropriate headings and is displ ayed in

bold printing.

3



- - ~ AMILIARIZATION MANUAL.

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TYPICAL OVERALL DIMENSIONS

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SPLICE

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STA. 555.0

FORMER

STA. 220.0

STA.160.0

SPLICE]J

BEAM

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"B" MODEL262.0

POD STRUCTURE

STA.238.0

)1 STA.O.OBULKHEAD

PRIMARY STRUCTURE

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I)I1 I I a ~

FAMILIARIZATION MANUAL..

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FWD~ COCKFIT

S E C T I O ~ ~

CABIN

PYLON

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AFTCROWN FAIRING",--~ ~ ~

rT1F A I R I N G TAIL FAIRING

SECONDARY STRUCTURE

6



t m r a ~fAMILIARIZATION MANUAL}) ...

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AIRFRAMEThe CH-47 fuse lage is of s e:m.i-:m.onocoque

const ruc t ion , consis t ing of fra:m.es, s t r inge rs

and bulkheads covered with s t r e s sed alu:m.inu:m.

}) panels . Fra:m.es and bulkheads a re the t r ans

v e r s e :m.e:m.bers of th e s t ruc tu re ; s t r inge rs and

longerons a re the longitudinal :m.e:m.bers. F o r

:m.ers or bea:m.s a re s tra tegical ly located to

support concentrated loads such as trans:m.is

sions, power plants and landing gear . The

j\ pr inc ipa l :m.aterial used in fuselage const ruct ion

is h igh- s t r eng th alu:m.inu:m. alloy.

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1\The fuse lage is divided into four sect ions:

J'the fo rward cockpit, the cabin fuse lage , the aft

fuse lage , and the aft pylon. The fo rward cockpit

is co:m.pletely fabr icated and asse:m.bled pr io r

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to splicing to the cabin fuse lage sect ion at s ta

t ion 160.00.

The cabin fuse lage is a constan t sect ion co:m.-

posed of four panels: th e crown, left and r ight

side, and botto:m.. When covered by th e car go

floor, the lower sect ion for:m.s a water t ight

co:m.part:m.ent, necessa ry for water landing ca

pabil i ty.

The aft fuse lage sect ion contains the cargo

ra:m.p and door , and is sp l iced to th e cabin

fuse lage at s ta t ion 440.00. The aft pylon is

at tached to th e aft fuse lage sec t ion at a field

spl ice . To per:m.it t ransporta t ion of the hel icop

te r within a li:m.ited space , the aft pylon can be

r e:m.oved.

7



I I m a ~..AMILIARIZATION MANUAL (

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SWIVEL LOCK

ACTUATOR

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UPPERDRAG L 1 N ~ / , A I W

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LOWEREND CAP

DRAG LINK

[:AFT GEAR

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LANDING GEAR

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II - ~AMILIARIZATION MANUAL.

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1) LANDING GEAR

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The landing gear systeITl consists of four

non- r etractable landing gear s: tw o fo rward

and tw o aft. The forward landing gear asseITl

bl ies a re fixed non-swiveling type, with tw o

wheels per as seITlbly, while th e aft gear uti l izes

one wheel per asseITll:Jly. A power s teer ing unit

is insta l led on th e r ight aft gear only. SOITle

early CH-47A a i rc ra f t a re equipped with s tand

a rd aft gear with tw o wheels a t each location,

but without power s teer ing.

The forward landing gears a re in terchange

able and each cons i s t s of an ai r -o i l type shock

s t ru t and tw o brake asseITlblies . The upper

sect ion of the shock s t rut contains ITlounting

lugs and i s secu red to th e hel icopter s t ruc tu re .

The lower sect ion contains the axle on which

the wheel asseITlblies and brake asseITlblies a re

independently ITlounted. A sc issor- type torque

link asseITlbly i s connected between th e upper

and lower sect ions of the shock s t ru t to prevent

the lower sect ion froITl turning.

Each aft landing gear cons i s t s of an ai r -o i l

type shock s tru t , tw o drag l inks, a swivel hous

ing, an axle and one brake asseITll:Jly. (Power

s teer ing type gear only.) The upper end of th e

shock s t ru t and th e fo rward end of each drag

link a re secured to th e fuselage; th e other ends

ar e secured to th e swivel hous ing which aSSUITles

a t ra i l ing posit ion.

The swivel housing includes a hydraul ical ly

operated caITl for center ing th e wheels in th e

t ra i l ing posi t ion during f light, while a swivel

lock is provided to secure theITl in this posi t ion

when desired.

The landing gear brakes a re hydraul ical ly

operated. Each wheel of th e fo rward landing

gear i s equipped with a single brake disk and

a 3 - s p ot brake unit. The fo rward brakes a re

used for stopping and park ing . To operate

theITl, th e brake pedals a re depressed and th e

park ing brake knob is pulled out.

Each wheel of th e aft landing gear is equipped

with a single brake disk and a 3 - s p o t brake unit .

On landing gear equipped with power s teer ing,

the aft brakes operate with the fo rward b rakes

when the swivel locks a r e engaged.

9



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21 AFT TRANSMISSION

., UTIl!TY H,YDRAULIC SYSTE.M TANK'

23 RAMP

" 24·' EN.GINE ;

25 ENGINE TRANSMISSION26" RESCUE HATCH'DOOR',

27 LEFT FUEL TANK

28 BATTER,Y:, . - : " : C _ ~ ~ ' ; 29 A,C AND D,C EXTERNAL POWER RECEPTACLES

30 CABIN ESCAPE HATCH

31 JqTISONABLE DOOR

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2 CABIN FUSELAGE SECTION,

")"'; AFT CABIN'?ECrioN' 1 .

4 PYLON SECTION

:5 ' . I N S T R U M E N T P A ~ E t AND CClHSOLE C

.. .6 PILOT'S S E ~ r . , •.

'i FORWARD TRANSMISSION'., ;,:1.,,' ) ; ' : ~ B ' ) F : ~ : A ; : ~ O ~ ~ ~ ; t L : ~ S S E ~ B C Y

9 DRIVE S H A ~ T ._ , ,. " r - . ' · I ,10"" CABIN D O O R ~ ( , . ' (j : ' : , ' ~ 1 t..

11 COMBINING TRANSMISSION

12 ENGINE TRANSMISSION AND COMBINING

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L '15 "ENGINE TR'ANSMISSIOtl AND COMBII-lING'

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. 18 'AFT ROTARY,WING'DRIVE SHAFT'19 FLIGHT CONTROL HYORAULIC SY.H,EM TAHKS..20 AUXILIARY POWER UNIT' ., ' ... , . ,.

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GENERAL ARRANGEMENT

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- ~) ... FAMILIARIZATION MANUAL

)1

GENERAL ARRANGEMENT

The cockpi t sect ion contains the fo rward

t ransmiss ion , th e cockpit control assembl ies ,

th e pilo t 's and copi lot ' s seats , th e hois t winch,

and the en t r ance door, which is loca ted on th e r ight-hand s ide . The door consists of tw o

sect ions tha t open independent ly . The upper

sect ion rools upward on t r acks and a la tch

holds i t open; the lower is hinged a t the bot tom,

opens outw ard, and contains an in tegral s tep .

Two in tegral w o rk plat forms on the fo rwardpylon fa i r ing faci l i ta te maintenance of th e for

ward ro tary-wing sys t em.

The cabin fuselage sect ion contains t roop

seating and provisions for l i t te rs , and se rves

as the major payload carrying a rea . Skid r a i l s

and t . ie-down r ings a re at tached to the flooring

to as s i s t in the loading and secur ing of cargo .

A r e scue hatch is loca ted in the cabin floor a t

the center of th e sec t ion and an ex te rna l car gohook is located in the hatch compar tmen t . Dra in

valves a re located in the bottom skin to p e r m i t

draining of th e bi lge a rea .

Fair ing, fo rmin g a tunnel atop the cabinfuse

lage sect ion houses the dr ive shafting, var ious

f light contr 01 components , ce r ta in e lec t r ica l

cables , and hydraul ic and lubr icat ion l ines . A

walkway is located adjacent to th e tunnel.

A detachable pod is loca ted on each s ide of

the cabin fuse lage sec t ion . These pods house

the fuel tanks, the mountings for the four land

in g gear , and certa in components of th e elec

t r i ca l and elect ronic sys tems .

The aft cabin and pylon sections contain the

combining t r ansmis sion, the aft t r a n s m i s sion,

re la ted dr ive shafting, th e auxi l iary power unit,

and th e ramp . The engines a re mounted ex

ternal ly on th e aft fuse lage sect ion and a re

housed within individual nace l l es . An engine

t r ansmiss ion is mounted on the f ront of each

engine.

Work p la t fo rms , in tegral with the fuselage,

provide easy access to the engines. The aft

pylon leading edge fai r ing is hinged to open

l ike a c lamshe l l f o r acces s to th e combiningt r a n s m i s sion.

The CH-47B fuselage is similar in construction to that of

the CH-47A. The right- and left-hand pods contain struc

tural provisions for the addition of auxiliary fuel tanks

forward and aft of the main fuel tanks. The af t pylon

trailing edge is blunt with removable fairing. Strakes are

incorporated on each lower side of the aft fuselage and

ramp to provide increased directional stability.

11



,JI m a ~FAMILIARIZATION MANUAL.

2ND TURBINE 3RD TURBINE

RDTOR DISC ROTOR DISC

COMBUSTION

CHAMBER

OUTER HOUSI NG

N.II GOV ERNOR

DRIVE

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CUTAWAY VIEW OF

LYCOMING T55-L (T55-L-7) SHAFT TURBINE ENGINE

12



J . . ~ AMILIARIZATION MANUAL..

POWERPLANT

The CH-4 7A hel icopter is power ed by ei ther

tw o Lycoming T55-L-5 or tw o T55-L-7 shaf t

turbine engines housed in separa te nacel les

mounted external ly on th e sides of the aft pylon

sect ion. The T55-L-5 is ra t ed a t 2,200 shaf t

hor sepower at mil i ta ry power, while th e T-55

L-7 engine is ra t ed at 2,500 shaf t hor sepower at

mi l i t a ry power and, in addition, 2,650 shaf t

hor sepower at maximum powe r . Amodif iedfuel

cont rol and severa l in ternal impr ovemen t s ac count fo r the power inc rease .

Each engine is ma de up of tw o sect ions: a gas

producer sect ion and a power turbine sec t ion.

These tw o sect ions a re not mechanical ly con

nec ted, but the hot gases produced by combust ion

flow f rom on e unit to th e other . During engine

start , ai r enter s th e engine in let and is com

pres sed as i t passes through var ious stages of

th e compresso r ro to r . The compressed a ir

passes through a di ffuser and into the combust ion

chamber , wher e i t is mixed with s tar t ing fue l

and igni ted.

After the engine is s tar ted , i t continues to

operate on mete red main fuel which is supplied

to th e vapor ize r s . Hot expanding gases leave

the combust ion chamber and dr ive a compres sor

turbine which in tu rn drives th e compresso r

ro tor . Remaining ener gy f rom the combust ion

gases dr ives the power turbine which in turn

drives th e power output shaft of the engine

t ransmis sion.

Maintenance, removal , replacement, or

"qu ick -change" of ei ther engine is facilitated

by the location of th e nacel les , th e design of th e

engine mounts and th e use of quick-disconnect

couplings on all l ines leading to th e pr i m ary

s t ruc ture . Each engine is secu red by th ree

mounts : tw o forward and on e aft . Nor mal ac

cess for maintenance is gained through hinged

access doors on ei ther s ide of the engine covers .

Th e CH-47B helicopter is powered by two Lycoming T55

L-7C engines of the same basic configuration as the

earlier T55-L-5 and T55-L-7 engines. The T55-L-7C

engine is rated at 2,850 shaft horsepower at maximum

power. The major internal modifications which produce

the increased power rating include the incorporation of a

fuel atomizing combustor rather than a vaporizing type,

improved spray nozzles for fuel injection, improved start

ing provisions and a modified fuel control.

13



. . FAMILIARIZATION MANUAL. ~ ENG NO. I ~ ENG NO.2

® ®FUEL VALVE \J(7 FUEL VALVE

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VALVE

MANUAL

SHUT.OFF

VALVE

APU

BOOST

PUMP

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/ BOOSTER PUMP

BOOSTER PUMP

FUEL SYSTEM

14



--- ~ AMILIARIZATION MANUAL

FUEL SYSTEM

The fue l supply system furnishes fuel for the

tw o engines, the auxi l iary power uni t (apu), and

th e hea te r . This system consis ts of tw o sepa

r a te fue l sys tems which a re i n t e r connec ted by

a crossfeed l ine and va lve . The sys tem is so

designed that each tank normal ly suppl ies fue l

to the corresponding engine . Under emergency

condit ions, ei ther tank can be valved through a

cros sfeed system to supply fue l to both engines .

During normal operat ion, fue l fo r the apu andth e heater i s suppl ied through th e lef t -hand

supply sys t em; however , fue l can be suppl ied

through th e r ight-hand supply sys tem th ru th e

c ros sfeed sys tem.

Each system cons i s t s of a fuel tank housed

within a pod, th ree fuel quanti ty measur ing

uni t s within each tank, tw o ac opera ted boos te r

pumps , tw o f loat-control led solenoid valves,

and a fue l va lve . Each boos te r pump deliversfue l through a se r i e s of valves and l ines to th e

fuel control uni t on the engine. I f a boos te r

pump fa i l s and the fuel l eve l in the tank is suf

f ic ient to cover both f loa t switches, the solenoid

valves will r e m a i n open and the engine fue l

pump will continue to draw fue l from the tank.

A check valve in the re la ted l ine preven t s fue l

from being pumped back into the tank through

th e inoperat ive pump. I f a boos te r pump fa i l s

o r becomes exposed due to lo w fue l l eve l and

a i rc ra f t a t t i tude , and the re is insuff ic ient fuel

to cover th e f loa t switch, the solenoid valve

wil l c lose to preven t the engine fuel pump f rom

drawing a ir through the exposed pump. In th e

event of lo w fuel pr e s s u r e , a caution l ight fo r

th e re spec t ive sys tem w a r n s the pi lot . The fuel

supply to a malfunct ioning engine can be shut

off by pulling th e f i r e control handle in th e

cockpit . This electr ical ly ac tua tes the fue lvalve.

T he in terchangeable fue l t anks each have a

315-ga l l on (2047.5 pounds) capac i ty . Ne we r

s e l f - sea l ing t anks have a capaci ty of 310.5

gal lons (2018.25 pounds) .

Vent l ines extend along the to p of each fue l

tank; fuel cannot escape f rom these l ines in

n o r m a l hel icopter at t i tudes . Fue l quant i ty for

each tank i s read on a c ommon indicator throughth e use of a selector swi tch. When th e switch is

turned to th e indicated tank, a capaci t ive signal

is rece ived f rom th e measur ing uni ts in that

sys tem only and th e fuel quanti ty is indicated on

th e indicator . Tota l fuel in a ll tanks i s indicated

when the swi tch is on TOTAL. A caut ion l ight

fo r each tank warns the pi lot when the re is 20

per cent of fue l (b y volume) r emain ing in th e

cor r espond ing tank.

15



. . ~ AMILIAIIiZATlON MANU AL..

ENGINE CONDITION

CONTROL PANEL

( ,

NO.2 ENGINE

CONTROL B.OX --C--)/ - - ~

(U I~ " ~ENGINE DROOP ' - ~ /

ELIMINATOR"'-... I I

I I

NO.1 ENGINE

CONDITION RELAY

EMERGENCY " ~ RIM RELAY

NO.1 ENGINETHRUST CONTROL

CONTROL BOX \ ) ~ /RIP ASSEMBLY

GAS PRODUCER

CONTROL ACTUATOR I'POWER TURBINE

CONTROL ACTUATOR

POWERPLANT CONTROL SYSTEM

16



I )

D a ~ .. FAMILIARIZATIO/ll MANUAL

POWERPLANT CONTROL SYSTEM

The powe rp l a n t control systeIT1 provides in -

dependent reIT10te control of each engine. Th e r e

a re tw o subsysteIT1s within each engine control

systeIT1: a gas producer con t ro l systeIT1 and a

pow er turbine control systeIT1.

The controls fo r the gas producer sec t ion

consist , priIT1arily, of an engine condi t ion l eve r

on the console , an ac tua to r on the engine , and a

fuel con t ro l unit. The speed of the gas producer

sect ion of the engine i s control led by the gas

producer l ever on the engine fue l control uni t .

MoveIT1ent of the engine condi t ion l ever e lec -

t roIT1echanically posi t ions the gas producer

l ever which prograIT1s fuel to the gas p r o d u c e r

sect ion. When the engine condi t ion l ever is in

S TO P , fue l to the gas producer sec t ion is shu t

off; when the l ever i s in GROUND, star t ing fue l

is prograIT1IT1ed; and when the l ever is in

F LIG H T, IT1axiIT1uIT1 fuel is perIT1itted to f low to

the gas producer sec t ion.

T he controls for the pow er turbine sect ion

cons i s t of tw o beep triIT1 swi tches on each

th rus t control s t i ck, tw o eIT1er gency engine triIT1

swi tches on the engine condi t ion control panel ,

tw o dual droop-eliIT1inator var i ab le r e s i s t o r s

(potentioIT1eters), two beep triIT1 re lays , an

eIT1ergency engine triIT1 re lay, tw o adjustable

r e s i s t o r s , an engine condi t ion control box, and

an ac tua to r connected to the turbine spe e d

se lec to r l ever on the engine fuel control uni t .

T he speed of the pow er turbine sect ion of the

engine i s control led by the power t u rb ine speed

se lec to r leve r . One beep triIT1 swi tch opera tes

the pow er t u rb ine l ever ac tua to r s of both en-

gines to regulate the power turbine and r o t a r y -wing rpIT1 by i nc r eas ing o r decreas ing the fuel

supply . The second beep triIT1 swi tch posi t ions

the p o w er t u rb ine l ever of the N o .1 engine to

IT1atch the output torque of the tw o engines . The

engine beep triIT1 c i rcu i t s control power turbine

rpIT1 only when the re la ted engine condi t ion

l ever i s in F LIG H T.

The droop eliIT1inator potentioIT1eters, IT1ech

anical ly l inked to the th rus t control systeIT1,cause the power t u rb ine l eve r to IT10ve when the

th rus t control set t ing is changed, t he r eby au to -

IT1atically cOIT1pensating fo r var i a t ions in power

turbine speed which a re caused by changes in

pow er deIT1ands on the engine. T he eIT1er gency

triIT1 switches a re used to change the spe e ds of

the power turbines if the norIT1al beep triIT1

systeIT1 IT1alfunctions.

17



lila.. --...==-{ ;

FAMILIARIZATION MANUAL

I

l

0 1'\

YPRE SS APU@

0) '0 ~ ? L W 0+ STOP@:

A '0 ~ ~ G H H START~ TEMP

~ O V S P ( ,g @ APU TACH @

ENGINE SHRT

E I ENGINE NO.1 ~ Ir - ENGINE NO.2 ~ PANELN IGNITION START FUEL IGNITION START FUEL

: ((::;)OFF {())CLOSE (())OFF ( '(ljCLOSE{ ,

T DON 'tJOPEN ' (JON 'O'OPEN

A

START START

@J @ o© ~ " " : ~ , , " ~ : Q \ " ,' l" , , ; / ' : ,\( ) ' ".

,c;;1',:' ,/ '/" ' ,.Vfi/Jl;\',C"j , ' ' ' / ' ( ,' ; : s - ' - ~ W '."'"v', . ',J J~ - " (.

, /' / " ". ';p;.•1/ ,

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11 / / , " ~ , • J' " '" '. 'yc," , , ~ . / , l -? 7, ~ ~ / t jJ ~ , v ~ : : ~\; Y , ' ~ 0 ~ > ~ , ( ; "

/ ii"" (. J""'>::t , / \ ( J ; ~ / . -, , . ~ , . ; ~ . / ' , I - c : ~ J <"Y

I\ ! , ! . ~ . ' ", y/ / ~ / '" ~ ~ i :>( ",r): t2J" ~ ~ , I ...-

"I l / > ~ j JY y/ 11 ' ~ ; ; !II I I~ l ) C ~ ~

I " , ~ , ,/ j ." '~ NGINE START VALVE = 00.--=:7 d ' I,~ , / : ) /1( '

{" - ' ~ ) E ~ ' I"J''// '" ,::>1'\,../' ->'J~ 1

ENGINE START AND APU { :

18 1'



1 I t a ~ FAMILIARIZATION MANUAL..

ENGINE START AND IGNITION

The helicopter contains a separate s tar t ing

an d ignit ion system for each engine. Each

ignit ion system consis ts of an ignit ion exc i te r ,

tw o igni ter plug s , an ignit ion lead as s embly, an

ignit ion swi tch , an d th e neces sary swi tches ,

r e lays , an d wiring required to in terconnect the

s tar t ing an d ignit ion s y s t e m s .

The ignit ion exc i t e r conver t s lo w voltage

dc to pulsat ing high voltage through the use ofa v ib ra to r an d a t r a ns f o r me r . The high tension

cur rent is ca r r i ed by the ignit ion lead assembly

from th e exciter to a spa rk sp l i t t e r which con-

ta ins high voltage coils . High voltage is then

dis tr ibuted by the ignit ion lead assembly to tw oI igni ter plug s in the engine.

Each engine has a hydraul ic ally poweredi s t a r t e r motor . The hydraul ic pres sure which

operates th e s ta r te r motor is provided by the

utili ty hydraul ic sys tem. (See Util i ty Hydraul ic

System an d A PU Sy s t em fo r details.)

To s ta r t ei ther engine, the respect ive engine

condit ion l eve r is moved from the STOP posi -

t ion to the GROUND posit ion, the s tar t ing fuel

swi tch is moved to the OPEN posi t ion , an d th e

ignit ion switch i s turned ON . When the s tar t

switch is depressed , hydraul ic power, s tar t ing

fuel, an d ignit ion a re automat ical ly supplied to

that engine. Simul taneously , the engine s tar t

valve opens allowing utili ty system hydraul ic

pres su re to be provided to th e proper engine

s ta r te r m o t o r . When the ut i l i ty system valve

c loses , th e engine begins to motor or ro ta te .

At approximately 12 percent engine r p m , a

percen tage of main fuel i s me te red to th e

engine along with the s tar t ing fue l . As th e

engine rpm inc reases , the percen tage of main

fuel to the engine is inc reased .

The engine can be motored by depressing th e

s ta r t swi tch when the star t ing fuel switch is inCLO S E, the ignit ion switch is O F F , an d the en-

gine condit ion l eve r is in STO P. When th is

procedure is followed, the engine wil l cont inue

motoring only while the s ta r t swi tch is de-

pressed.

19



I

. . ~.. FAMILIARIZATION MANUAL

ENGINE CUT-A-WAY

/ ~ ~ - - - ; ; > ~ ~ ' / ~ - - ~ \ ~ ,.c1 "" '0 ' " 'I ,_ " : - - q ' ~ '-it \'\'

( " ' \ \ r ~ " ' \ ' ~ ~ . \ \ . ': \ \\\jJ ,\ \"\ \\ '\ \ \ i

------ \ . I' k ~ \ t' )1

\ J : ~ i f ' ~ ~ ' : v t ) i !/)ENGINE TRANSMISSION AND \ " ~ s ' % J ~ ~ U RIVE SHAFT FAIRING

HOT AIR FAIRING VALVE

/1.50 INCH DI A NORMALL Y OPEN, FLEXIBLE DUCT SOLENOID DEENERGIZED

FLEX IBLE !D U C T ~ I /

1'PilOT

HEAT

® ©J @ ® ""'

INLINE VALVE

NORMALLY OPEN,

SOLENOID DEENERGIZED

ENGINE INLET

FAIRING

" ' ~ - = : ~ '\

ENGINE ANTI-ICE

ENGINE ROTORON F CO-PILOT CENTER PILOT

&)OFF

I ANTI-ICE ANTI· FOG ANTHeE I ON HIGH Ic ANTI-FOG ANTI-FOG

T @ @ @ (Q)L ANTI-ICE ~

E ~

ANTI-ICE CONTROL PANEL

I1

{

t

20



1

J a a ~ ... FAMILIARIZATION MANUAL

ANTI-ICING SYSTEMS

There a re four anti- icing systems insta l led

in th e helicopter which protect the engine,

por t ions of the s t ructure , th e pitot tube, SA S

ya w por t s , and th e wind shield. Thes e sys tems1,J a re control led from the anti- ice panel of the

overhead swi tch panel .

The engine anti-icing system is a function

of tw o sources: hot a ir ducted to the inlet

guide vanes an d thermal radia t ion produced bythe ' oil tank located within the inlet housing . A n

e lec t r ica l ly operated engine hot a ir valve is

posit ioned on the top lef t -hand side of the engine.1c ompr e s s o r housing, direct ly behind an d to the

lef t of the s t a r t e r dr ive housing . When opened,

th e valve allows hot a ir to flow from th e c o m

pres so r diffuser sect ion to the in ternal passages

of th e inlet housing, preventing the format ion of

ice on th e hollow inlet guide vanes. Addit ional1

an t i- i ce protect ion i s provided by therm-al rad i a t ion f rom the hot oil in th e oil cavity of the

}

inlet housing which w a r m s the a ir as i t passes

into the engine in le t .

Ant i - ic ing is also provided for th e engine a ir

inlet fa ir ing, engine t r ansmiss ion fa ir ing, an d

th e dr ive shaft fa ir ing. Hot a ir is tapped from

th e engine a ir bleed gallery , through a valve

an d ducted to the leading edge of the fai r ing,

where i t c i rcu la te s before escaping th rough

smal l holes in the t ra i l ing edges . To prevent

ice accumulat ion in the pitot tube and SA S yawports , e lectr ical ly operated heat ing e lements

a re provided at each locat ion •

The pilo t 's an d copilo t 's windshields a re

anti- iced an d defogged e lec t r ica l ly . The cen te r

windshield i s ' defogged only. The laminated

plas t ic windshield panels a re heated by cur rent

pass ing th rough a t r anspa rent conductive coating

embedded between the l aye r s . The tempera ture

of each individual windshield is automatical lymaintained by a sensor e lement and con t ro l le r .

21

t"



- ~AMILIARIZATION MANUAL. i '

~ EXTINGUISHING

AGENT

CONTAINERS

//

SENSING UNITS

/JV\

/ ~ ;;0. . ~ ~ " ,

" /-------- c

\ ~ - - - \ " ~ / .~ " \ ~ - ~ ~ 't r O ' : ~ :: t ~ ~ ' S \ ;

, , ~ ~ ) ~ " ' J - ~

{ ,

{

l

[

1 '

'</ LIRE CONTROL PANEL (------..-----"0

~ ~ ~ d ~ _ _' \ ( '\ \FIRE DETECTION AND EXTINGUISHING SYSTEMS \ ~ \ J r:

22 l



1 I F a ~ FAMILIARIZATION MANUAL..

FIRE DETECTION AND EXTINGUISHING SYSTEMS

The f i re detect ion system consis ts of tw o

ident ical circui ts , on e c i rcu i t for each engine

compar tmen t . Each c i rcu i t consis ts of three

se r i e s - connected, cont inuous- type, sensing ele

ments which a re routed around the engine an d a

control unit mounted on th e a i r f r ame .

When ei ther f ire detect ion circuit i s energized

by an abnormal increase in the engine t empera

ture , th e corresponding f i re control handle onJ th e in s t rumen t panel i l luminates .

The sensing elements a re cons tructed of

Inconel tubing with a nickel wire center con

duc to r that is surrounded by a sal t compound

and insulat ion. The e lements are hermet ica l ly

sealed with water- t ight elec tr ica l fittings at

the i r ends . The tubing can be bent or rebent to

a radius of no t les s than on e inch . The her

metical ly sealed control unit contains a t e s tc i rcu i t re lay .

A t e s t swi tch located on the in s t rumen t panel

is used to check the operat ion of th e f i re detec

t ion sys tem. When the switch is pushed in, a

re lay in each control unit closes which co m

pletes the c i rcu i t , and the f i re warning l igh ts

corne on.

The f i re extinguishing sys tem cons is t s of tw o

f i re control handles an d af i re ext inguisher agent

switch located on the in s t rumen t panel an d tw oextinguishing agent containers mounted in th e

aft pylon. The containers a re part ia l ly filled

with bromotr if luoromethane (CBrF3) an d pres

surized with ni t rogen. When ei ther f i re control

handle is pulled out, th e respect ive engine fuel

valve is closed an d th e f i re ext inguisher agent

switch is a r m e d . The agent in e i the r one or

both containers can then be discharged into

ei ther engine compar tmen t th rough in tercon

necting tubing by select ing the des i red containerwith the agent swi tch .

23

{,



- ,FAMILIARIZATION MANUAL

I

t

t

LAUXILIARY POWER

UNIT

{ "

AUXILIARY POWER UNIT l.24 1



- ~ AMILIARIZATION MANUAL..

AUXILIARY POWER UNIT

The auxi l iary powe r unit (apu) consis ts of a

gas turbine engine, hydraul ic motor - pump and

the fuel control . The apu provides hydraul ic

pr e s s u r e f rom th e motor -pump to hydraul ical ly

actuate th e acces sory gear box (agb) pump, thus

supplying the neces sary 4, 000 ps i pres sure to

actuate th e main engine s t a r t e r motor s . Two

ac genera to rs , tw o f l ight control hydraul ic

system pumps , an d a util i ty hydraul ic sys tem

pump a re mounted on th e agb. Thus, the apu iscapable of supplying the neces sary power re

quired fo r th e ground operat ion of al l the heli

cop te r sys tems .

Normal ly , for star t ing th e apu, th e accumu

l a to r i s p res su r i zed by previous operat ion of

the ut i l i ty hydraul ic sys tems . However , an

insta l led hand pump can be util ized to pres su r ize

the accumulator .

In t e rna l sensing switches in th e apu system

pro tec t against abnormal opera t ion condi t ions ,

including overspeeding, excessive exhaust gas

t empera ture , an d lo w oil pres sure . The apu

control swi tch, t achomete r , an d warning l ights

a re located on the overhead switch panel .

The auxi l iary power uni t is mounted in thel ower sect ion of the pylon. The forward en d of

the unit r e s t s on two pad- type suppor t s which

a re a t tached to the a i r f r ame . The aft en d of the

unit is suppor ted by tw o l inks, a ver t i ca l l ink at

th e 12 o 'c lock posi t ion an d a hor izontal l ink at

th e 9 o 'clock posi t ion. Both l inks a re bolted to

th e a i r f r ame at one end and to a fitting which

is threaded into the apu at the o ther end.

25



- ~AMILIARIZATION MANUAL...

r

AFT ROTARY-WING

DRIVE SHAFT

TRANSMISSION

OIL COOLING FAN

ENGINE SHAFT

ENGINE COMBINING

TRANSMISSION ~ ' ~ / / ~ ' ( " " /1 "'" TRANSMISSION OIL/ ~ / COOLING FAN DRIVE SHAFT

FORWARD

SYNCHRONIZING SHAFT /:#/

J ~ AFT

SYNCHRONIZING SHAFT

FORWARD-;::.;,RIVE T ~ ~ N T A R Y - W I N G

SMISSION ~ - - ~ -l7i /\ \ -

/::Jl ; ; ~ \ ~ , \ \ -

t ? F - ~ ~ /--1/ ' I . :} 1/ /~ - - - = I \ r L - ' - 1 ! " ~ ." /,1{) / - _ . - - - / ~ ! - - ~ / ~

POWERTRAIN

26 1

1



1 ! F a ~FAMILIARIZATION MANUAL...1

POWERTRAIN

The CH- 47 power t ra in cons i s ts of five t rans

miss ions , interconnect ing drive shaft ing, the

aft ver t ica l shaft, an d the oi l cooler fan ass em

bly. One drive shaft (engine shaft) is connected

J from each engine t r ansmiss ion to th e combining

t ransmis s ion.

Seven sections of shaft ing ( forward synch

ronizing shaft) a re connected from th e combining

t ransmis sion to the forward t r ansmis sion; an dtw o sections of shaft ing (aft synchronizing shaft)

a re connected from th e combining t r ansmiss ion

to the -aft t r ansmis s ion. Two shaf ts are dr iven

by th e af t t r ansmis sion: one (aft ver t i ca l -dr ive

shaft) , drives the af t ro ta ry -wing head, an d the

other (fan drive shaft), drives an oil- cooling

fan.

The shafts a re seamless aluminum alloy

tubes . The engine shafts , the oi l cooler fa n

shaft, an d th e aft section of the forward syn

chronizing shaf t have forged aluminum adapters

r iveted to each end. The f i r s t six sect ions of

the forward synchronizing shaft, which a re in

terchangeable , have forged aluminum adapters

r iveted to one end an d an in ternally splined s tee l

adapter . The adapter contains a shaft bearing

and housing assembly an d a flexible coupling.

The aft ver t ica l dr ive shaft has s tee l spl ines at

both ends.

Each shaft and adapter assembly is dynam

ical ly balanced as a uni t . The shaft ing is sup

por ted by shock mounts which a re at tached to

the bearing housing s an d secured to th e s t ruc

ture .

Flexible couplings, cons is t ing of s ta inless

s tee l plates are us ed to absorb differentia l

act ion at each shaf t - section juncture , excepting

th e aft ver t i ca l shaft . The couplings a re also

bolted to the t r ansmiss ion an d oil cooler adap

t e r s . The shaf ts are , in turn, bolted to the

coupl ings . The adapters an d the i r respect ive

couplings a re individually balanced as units .

The aft synchronizing shaft is constructed

an d suppor ted in the same manner as th e for

ward shafting. How ever, the tw o sections of

the aft synchronizing shaf t a re no t in terchange

able .

The aft ver t i ca l dr ive shaft is externally

splined at each end to mate with the internal

spl ines of the af t t r ansmis sion and the aft

rotary-wing hub. A thrus t bearing an d housing

as sembly is insta l led over th e upper section of

th e shaf t an d is bolted to the pylon s t ruc ture .

27

f '



D a ~.. FAMILIARIZATION MANUAL I :r:

TANK ASSEMBLY

(B OR C)

PINION SUPPORT

AFT

SYNCHRONIZING

SHAFT ADAPTER

!(

DEPHASING

LOCKING BRACKET [PINION SUPPORTCASE AND COVER

f:COMBINING TRANSMISSION

f :

28 f :

D I a ~



FAMILIARIZATION MANUAL.ENGINE AND COMBINING TRANSMISSIONS

The engine t r ansmi s sions a re attached to the

forward end of each engine. Power f rom each

engine is supplied to the respect ive t r ansmis -

s ion by way of a quil l shaft , which drives th e

spira l bevel pinion gear . The spira l bevel

pinion gear drives the spira l bevel gea r an d

shaft as sembly where th e d i rec t ion of torque

i s changed 90 degrees . Torque is then t rans-

mit ted through a one- way dr ive , overr iding

(sprag) clutch to the output shaf t . The sprag

clutch permi ts th e rotary-wing system to overr ide th e engine during autorotat ion or in th e

event of an engine fa i lure . A speed reduct ion of

1.26: 1 occurs within the engine t r ansmis sion.

Torque i s t r ansmi t ted from the engine t rans-

miss ions to th e combining t r ansmiss ion by the

engine shaf ts .

The tw o engine t r ansmis sions are ident ical

and can be used in ei ther pos i t ion by making

a minor mechanical convers ion.

The combining t r ansmis s ion receives the

torque delivered f rom both engine t r ansmis -

sions an d dis tr ibutes the combined torque to the

forward an d aft t r ansmiss ions .

The torque f rom both engines is combined

within th e t r ansmiss ion by means of two spira l

bevel input pinion gea r s an d a single spira l bevel

ring gear . The spira l bevel input pinion gears

receive th e torque f rom the engine t r ansmiss ions

a,nd both gears d r ive the ring gear . A speed re -

duction of 1.70 to 1 occurs at this point .

The t ransmit ta l of longitudinal torque is ac

complished by forward an d aft output shaf ts ;

th e ring gear is bolted to th e aft shaft . The tw o

shafts a re connected by a bear ing mounted

sl iding coupling. The coupling permi ts engage

ment an d disengagement of the forward an d aft

synchronizing shafts . The coupling mechanism

i s manual ly operated by means of a handle

mounted on th e r ight- hand side of the t r ansmis -sion. Tw o sens i t ive switches break the engine

s tar t ing circui t if the handle is in th e disen

gaged or unlocked position.

29

1 ! I a ~ !:



FAMILIARIZATION MANUAL. i .

\ :

ACCESSORY DRIVE HOUSING

LUBR ICATIONUPPER SUPPORT ASSEMBLY

PUMP

1 ;HOUSINGOIL FILLER

1 '

HOSE ASSEMBLY

LUBRICATION

PUMP

\ ;FORWARD

TRANSMISSIONS

f :

30 1:

AFT

I m a ~



~ FAMILIARIZATION MANUAL

FORWARD AND AFT TRANSMISSIONS

The forward an d aft t r ansmiss ions t r ansmi t

torque f rom the combining t r ansmiss ion to the

re spec t ive ro t a ry -wing heads. Torque is t r a ns

mit ted within the t r ansmiss ions by a sp i ra l bevel

input pinion gea r which meshes with a spi ra l

bevel ring gear . At this point, th e direct ion of

torque is changed from a horizontal to a ver t ica l

plane . The ring gear is bolted to the f i rs t stage

sun gea r . The sun gear , in turn , dr ives th e f i rs t

s tage planet gears which mesh with a s ta t ionary

r ing gear .

The nonrotat ing ring gear causes the planet

gea r s to revolve around the sun gea r . T he

planet gears a re attached to the f i rs t stage

ca r r i e r which also revolves around the sun

gear . The upper por t ion of th e f i rs t s tage

ca r r i e r fo rms the second stage sun gear an d

it dr ives the second stage planet gea r s . These

planet gears a re attached to a second stage

ca r r i e r an d revolve in th e same manner as th e

f i r st s tage planet gears an d car r ie r .

Three s tages of speed reduct ion take place

during the t r ansmis sion sequence resul t ing in

an overal l reduct ion ra t io of 30.72 to 1 o r a

66: 1 ra t io for the entire sys tem.

f

In th e forward t r ansmiss ion , the second s tageca r r i e r is bolted to the ro to r shaft ; in th e aft

t r ansmiss ion, the second s tage ca r r i e r is splined

to rece ive the aft ro tary-wing drive shaf t . The

forward t r ansmiss ion ro to r shaft is splined to

rece ive th e forward ro tary-wing head . The aft

ro tary-wing (vertical) shaft is splined to receive

th e aft ro t a ry -wing head .

The acces sory gear box is mounted on the

aft t r ansmiss ion. The t r ansmiss ion uses a

quil l shaft , which is splined into a sprag clutch

to dr ive th e accessory gea r s . The clutch per

mi ts the acc essor ie s to be driven by th e apu-

powered hydraul ic motor , independent of the

t r ansmiss ion whenever th e main powerplan ts

a re not running.

The ro tor t achomete r genera to r i s d r iven

by th e forward t r ansmiss ion. On recen t se r i e s

he l icop te rs , an e lec t r ic chip detector with cock-

pit warning l igh t is provided . A magnet ic plugis used on ea r l i e r ve r s ions .

The CH-47B transmissions are identical in principle of

operation. However, some in t e rn a I parts have been

strengthened either by a change in design or by improved

manufacturing processes so that they can accept the higher

torque input.

31

i I1 I t a ~



FAMILIARIZATION MANUAL.J '

COMBINING TRANSMISSION

OIL COOL ER NO 2

- - ?

TRANSMISSION OIL

PRESSURE TRANSMITTERS

/'

COMBINING TRANSMISSION

OIL COOLER NO 1

LIH ENGINE

TRANSMISSION

RIGHT HAND

ENGINE TRANSMISSION R/H ENGINE

TRANSMISS ION

TRANSMISSION OIL

PRESSURE TRANSMITTER

OIL

PUMP

'}/// '

/'

, ,/ \ 1<;' )I / / I ~ ' ,','1;;:/ : ! /,:> l '\ / - '

[ I

TRANSMISSION OIL ( ,PRESSURE TRANSMITTER

'\ {

'-

(LEFT HAND / ' '- _

ENGINE TRANSMISSION

{,

t 'TRANSMISSION LUBRICATION SYSTEM

32 l'



1- - ~

AMILIARIZATION MANUAL..

TRANSMISSION LUBRICATION

An individual lubricat ion system is provided

fo r each t r ansmiss ion . A 6- element pr e s s u r e /

scavenge pump for the engine t r ansmiss ions

and th e combining t r ansmiss ion is ins tal led in

the combining t r ansmiss ion below a 3- sect ion

tank.

The forward t r ansmiss ion oil pump is mounted

on the bottom of th e forward t r ansmiss ion ; the

aft t r ansmiss ion oil pump is mounted on the

accessory gear box. Each of these pumps sup

pl ies oil to lubr icat ing je ts by way of in ternal

pass ages in the respect ive t ransmiss ion .

Four oil coolers a re located in th e pylon.

Two coo le rs , composed of three sect ions , a re

for the two engine t r ansmiss ions an d th e co m

bining t r ansmiss ion . They a re connected in

se r i e s an d oil flow is continuous through both

of them. The other tw o coolers a re for the for-

ward and aft t r ansmiss ions . A ir is drawn

th rough these coolers by a fa n which is dr iven

by th e aft t r ansmiss ion .

A t r ansmiss ion oil pressure indicator an d

a se lec to r swi tch a re mounted on th e in s t ru -

men t panel . Depending on the pos i t ion of th e

se lec to r switch, the lowes t oil pr e s s u r e of all

th e t r ansmiss ions or the actual oil pres su re of

each t r ansmiss ion will be shown on the indicator .

Transmiss ion oil t empera ture i s indicated

in the s a m e manner a s the pr e s s u r e . The

indicator shows e i the r th e highes t t empera turepresen t o r th e t empera ture of the oi l in one

selected t r ansmiss ion.

Two caut ion l ights , one for pr e s s u r e and one

for t empera ture , a re located on the conso le .

Each t r ansmiss ion conta ins a magnet ic chip

detector with a remote reading circui t . An

accumulat ion of meta l pa r t ic le s ac ros s the gap

in th e chip detector plug comple tes an elec tr ica l

c i rcu i t an d i l luminates a warning l igh t on th e

auxil iary ma s t e r caut ion panel in the cockpi t .

33



I

- ~.. FAMILIARIZATION MANUA Lf

[

HUB OIL

TANK

ROTARY

WING

SOCKET

I\ I

SHOCK ABSORBER( ,

VERTICAL

PIN

PITCH

LINK

I'

i I

WEATHER

PROTECTIVE

COVER

DRIVE ARM

ASSEMBL Y

STATIONARY RING

CENTRIFUGAL

DROOP STOPS

(I

ROTARY-WING ASSEMBLYf \

34

............i I a ~FAMILIARIZATION MANUAL.



1ROTARY-WING HEADS

The ro tary-wing heads, splined to th e re spect ive ver t ica l shaft , receive torque from th e

forward and af t t r ansmiss ions and, in turn ,

dr ive th e ro tary-wing b lades . The heads a re

secured to the shaf ts by nuts .

Each head consis ts of a hub with three pitch

varying shaf ts a t tached to i t by horizonta l hinge

pins . These pins .permit blade flapping. On the

ear l ie r ser ies of helicopters , both heads utilized

s ta t ic droop stops at tached to the top an d bottom of th e shaf ts to l imi t blade flap an d droop.

On th e l a te r ser ies of helicopters , a centr ifugal

droop stop mechanism has been insta l led at th e

af t ro tary-wing head. Centr i fugal force act ing on

balancing a r ms at high rpm causes the inter

pose r blocks to move ou t from between th e hub

and pitch-varying shaf t . At lo w rpm, th e springs

overr ide the centr ifugal force an d position the

interposer blocks between the hub an d pitch

varying shaf t , thus reducing th e blade droopangle which, in turn , reduces th e possib i l i ty

of droop stop pounding.

Mounted coaxial ly over the pi tch-varying

shafts are pitch-varying housings to which the

blades a re attached by ver t i ca l hinge pins .

These pins permi t leading an d lagging move

ments of th e blades . Direc t -ac t ion shock

absorbe r s , connected betw een the blade assemblies an d pitch-varying housings, l imi ts the

blade lead an d la g motions.

The shock absorbe r s a re at tached to the

pitch-varying housings by quick-disconnect fit

t ings . Each pi tch-varying housing is in ternal ly

connected to th e pitch-varying shaft by a l ami

nated s tee l t ie bar . The laminated t ie bar al lows

th e pitch-varying housing to be ro ta ted on the

shaft , thus changing the blade pitch, while re

taining th e housing on th e pitch-varying shaft .

An oil lubricat ion system , consis ts of an oi l

tank for the horizonta l- pin bearings an d indiv

idual oil tanks for the pitch-varying bearings

an d the ver t ica l - pin bear ings . A plast ic s ight

cup, located on the outboard unders ide of the

pitch-varying housing, functions as an indicator

of oi l leakage past the pi tch shaf t oil seal .

The CH-47B rotary-wing heads retain the same basic con

figuration, but certain design changes have been incorporated to accommodate the droop snoot blades and other

refinements based on operating experience. The changes

include: new v e r t i ca l and horizontal pin bearings,

strengthened vertical pins to accept the greater weight

of the blades, and strengthened pitch arms and pitch

housings. The shock absorber quick-disconnect fittings

have been repl aced by a bol t connection and the pi astic

sight cups have been eliminated.

35

[m r a ~ ,

... fAMILIARIZATION MANUAL



IUPPER DRIVE ARM PITCH LINK

1 :

LOWER DRIVE ARM

ISWASHPLATE

. ROTATING RING !UAL

DRIVE ARM

ATTACHMENTLUGS

\ '

SWASHPLATE

STATIONARY

INNER RING

'-"1./ ,'.j., -- :',1\~ ~ . = J . ~ . ' ......Ju l ~ } : ; ! , . U : : ~ ~ ; ~ ~ r - 1 ,

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ROTARY-WING CONTROLS{

36 1

FORWARD INSTALLATION

"6 " MODEL

1 D 1 a ~FAMILIARIZATION MANUAL..



1ROTARY-WING CONTROLS

The ro tary-wing controls a re located aroundeach ro tary-wing head dr ive shaft , be tween the

pivoting an d swiveling actuators and th e ro ta ry

wing head . The forward and aft controls a re

s imi la r except fo r differences required by the

d i rec t ion of rotary-wing head rotat ion. T he

controls for each rotary-wing system consis t of

th ree pitch l inks, a control lable swashplate , a

dr ive - a rm assembly, an d a dr ive co l la r which

is splined to the ro tary-wing head drive shaf t .

T he control lable swashpla te consis ts of a s ta t ionary i nner r ing, a bal l bearing, an d an outer

rotat ing r ing. Both r ings a re assembled on a

convex, or ball shaped, i nner sl iding ring cal led

a bal l spher ica l bea r ing .

The bal l spher ica l bear ing moves in a ver t ica l

plane on the s l ide r shaft , thus providing ver t ica l

movement of th e swashplate . Tilt ing movements

occur on the convex surface of the bal l . The

hinged dr ive - a rm as sembly, which is bolted tothe co l la r , provides rotat ional force to th e

swashplate outer r ing. Movements of the pivot

ing and swiveling actuators a re directed to th e

swashplate s ta t ionary ring which t r ansmi t s the

force to th e swashpla te outer r ing. Pitch l inks ,

at tached to the rotating r ing, t r ansmi t th e force

to the pi tch-varying housings on the ro tary-wing

head. The pitch l inks a re adjus table an d con

t ro l the blade t ip path p lane . Flight control

movement , man u a l o r automatic , resul ts in ver

t ica l o r t i l t ing movement of the swashplate .

Movement of th e swashplate resul ts in a cor

responding mo v emen t of the blade plane .

The swashplate is lubricated by e i the r of tw o

methods: the or iginal des ign uses an oil tank

mounted on th e swashplate to supply oil to the

bal l bearing; th e l a t e r conf igurat ion is grease

lubricated th rough a single grease fi t t ing. D ry

teflon bearings a re used on th e bal l spher ica l

bearing.

A weathe r - p ro tect ive cover is insta l led over

the ro tary-wing controls . The cover is bolted

to , and ro ta te s with, the drive col l a r . Wate r

t ight boots seal th e openings in the cover th rough

which the pi tch l inks pass .

The CH-47B rotary-wing controls incorporate strengthened

pitch links and a strengthened rotating ring which permits

an increase in the input loads. The rotating ring also has

dual drive arm attachment lugs which allows interChange

ability of a swashplate assembly between the forward and

af t locations.

37

m r a ~AMILIARIZATION MANUAL.



!'

~ LEADING EDGE

~ _ IBERGLASS SKIN

/#

TRAILING EDGE

CHANNEL

TYPICAL SECTIONSPAR

o

o

o

o/ ~ ~ TIP COVER

oTIP BOX oBLADE BU ILD UP

CHORDWISE

BALANCE

ADJUSTMENT

BASIC BOX

ROOT BOX

TRACKING

WEIGHTS

SECTION AT BLADE TIPROOT SOCKET

i '

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ROTARY WING

38 I

. . ~ .. FAMILIARIZATION MAN UAL



1

ROTARY-WING BLADES

Each ro tary-wing blade assembly cons is t s ' ofa D- spa r , an at tachment socket , a nose cap as

sembly, t ra i l ing edge s t r ip, t ip balance pro

vis ions, an d a t ip cover . Three interchangeable

blade assembl ies a re ins ta l led on each ro ta ry

wing head .

The s teel D- spa r is c i rcula r at the root en d

and threaded to receive th e at tachment socket .

The at tachment socket is slot ted an d threadedand is screwed onto th e threaded root en d of th e

spa r . The socket is then c lamped by a bolt in

sta l led th rough lu g s fo rmed on ei ther side of

th e s lots in the socket . A special bolt is in

s ta l led through the socket an d the spa r to main

ta in th e prese t angular a l ignment or angle of

incidence of th e tw o par t s . The socket also

fo rms in teg ra l mounting lu g s for at tachment of

a d i rec t - action shock absorbe r .

The blade leading edge is a formed s ta in les s

s tee l nose cap with a balance weight assembly

bonded in ternal ly to i t . The leading edge is

then bonded to the D- spa r . Individual box fa ir

ings , consist ing of external skins , bonded to

airfoi l- shaped a luminum r ib s , a re in turn bonded

to the t ra i l ing edge of the D- spa r . A t ra i l ing

edge i s formed by bonding a ful l - length, l ami

nated s ta in less s tee l s t r ip between th e upper

an d l ower sk ins of th e fai r ing at th e aft end.

Movable t racking an d balance weights a re

insta l led on s ta in les s s tee l fi t t ings which a re

r iveted to the t ip of th e D- spa r . These weights

are used for making balancing an d t racking

cor rec t ions at th e factory .

To provide interchangeabi l i ty , a l l ro ta ry

wing blades a re balanced an d t racked to ma s t e r

blades at the factory . A r emovable tip cover

provides access to the weights . A t ie-down

f it t ing socket is located on the bottom surfaceof each ro tary-wing blade assembly nea r th e

t ip.

39

~.. FAMILIARIZATION MANUAL



. .BALANCE TUBE CONTAINER

TIP COVER

TRACKING WEIGHTS

PARTIAL SECTION AT TIP

TYPICIlL SECTION

[

I-------- - --I

TRAILING EDGE

HONEYCOMB CORE

~ FIBERGLASS SKIN

ROTARY WING

LEADING EDGE

BLADE BUILDUP

RIB

SPAR

f I

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1

1

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(DROOP SNOOT)

40 1I

1 - ~ .. FAMILIARIZATION MANUAL



ROTARY-WING BLADES (DROOP SNOOT)

Droop snoot (non-symmetrical) rotary-wing blades are in

stalled on the CH-47B helicopter. The non-symmetrical

airfoil provides increased blade lift capability and permits

a greater flight speed. The droop snoot blade is less sen

si ti ve to ro tor stall in gusts an d maneuvers du e to it s in

creased lift capability.

Construction of the droop snoot blade is similar to that

of the symmetrical blade. The leading edge is a formed

stainless steel nose cap with three additional tubes bonded

to it and the D-spar. Two of th e tubes are contoured to the

airfoil while the third is cylindrical in shape. The forward

inner tube is a provision for chemical anti-icing while the

cylindrical tube serves as a container for spanwise bal

ance weights. The aft tube serves as a spacer and support

for the cylindrical tube.

The fairings (blade boxes) are formed from aluminum

honeycomb and covered with fiberglass skin. Nine fairings

make up the rotary-wing assembly. Each fairing assembly

is bonded to the D-spar and plastic ribs are bonded to each

side of the assembly. A laminated stainless steel trailing

edge strip is bonded to the fairing assemblies along the

full length of the blade. A trim tab is bonded to the trail

ing edge.

Tracking and balance weight plates are attached to a

fitting at the D-spar tip. The weight required is deter

mined at the factory or at overhaul and is no t field adjust

able. Since the blades ar e tracked to master blades at the

factory, they are interchangeable, but only on the same

(forward or aft) rotary-wing head. A tie-down fitting socket

is located on the bottom surface of the blade near the tip.

41

fAMILIARIZATION MANUAL

1 ! I a ~..



AFT SWASHPLATE

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/PYLON

SECTION

CABIN SECTION AFT

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STATIONS 95.00 TO 120.00 CONTROLS

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42

COCKPIT CONTROLS

FLIGHT CONTROL SYSTEM SCHEMATICt ;

l !

1 a a ~.. FAMILIARIZATION MANUAL



FLIGHT CONTROLS

The fl ight control system of th e CH- 47 is

composed of tw o power boost sys tems , tw o

electronic stabi l izat ion sys tems an d a l inkage

sys tem, which mixes an d t r ansmi t s control

motions f rom the cockpit controls to the ro to r

heads . The l inkage is divided into six main

sect ions: Cockpit f l ight controls , f l ight con

t ro l s between stat ions 95.00 an d 120.00, fl ight

con t ro l mixing, forward upper f l ight controls ,

fl ight controls within the tunnel , an d aft fl ight

con t ro ls .

The pilot an d copilot each have a separa te se t

of cockpi t controls , in terconnected benea th the

cockpi t f looring. Movement of ei ther se t of

cockpi t controls re su l t s in a corresponding

movement by th e o ther set . Each cockpit con

t ro l as sembly conta ins a pitch an d rol l control

st ick, a th rus t control , an d direct ional peda l s .

Control movements in i t ia ted by ei ther th e

pilot o r the copilot a re d i rec ted from the cockpit con t ro l assembl ies to the vert ical controls

between sta t ions 95.00 an d 120.00.

Also contained within this sect ion of th e f l ight

controls the dual st ick- boost actuat ing cyl inders

which supply hydraul ic ass i s t for the cockpi t

f l ight controls , Stabil i ty Augmenta t ion System

r (SAS), a dif ferent ia l col lect ive- pitch (DC P) speed

and s t ick t r im actuator , spr ing assembl ies an d

magnet ic brakes . The spr ing as sembl ies an d

magnet ic brakes provide art i f ic ia l feel to th e

cockpi t control assembl ies ; no rmal feel is lost

due to the hydraul ic as s is t provided by the dua l

st ick- boost actuat ing cylinders . The dual ex

tensible l inks function as variable- length l inks,

control led by signals from th e SAS, o r as fixed

l inks i f the SA S is not operat ing.

Thrus t , pitch, yaw, an d ro l l control motions

a re directed to the mixing un i t s where the fourmotions a re combined to produce tw o in tegrated

movement s which a re t r ansmi t ted to the upper

con t ro ls . The resul t ing control mot ions a re

t ransmi t ted to the forward upper controls d i

rec t ly an d t r ansmi t ted to th e aft upper controls

by m e a n s of the l inkages in the tunnel fa i r ing.

Pivoting an d swive l ing dua l actuat ing cyl

inde rs a re ins ta l led in both th e forward an d af t

upper con t ro ls . These cyl inders a re connected

between th e helicopter s t ructure an d th e con

t ro l lable swashplates . Control motion to the

cylinders operate control valves which d i rec t

hydraul ic power to extend o r re t rac t the cyl in

de r s . The cylinders , in turn , move the swash

plates in cor r espond ing direct ions. Longi tudina l

cyclic t r im actuators which a re pa r t of th e

speed t r im system a re a l so . connected to th e

swashplates .

43



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1 B a ~ FAMILIARIZATION MANUAL..



NO.2 NO.1

SAS ON-OFF CONTROL ON-OFF CONTROL SAS

CONTROL CONTROL

VALVE VALVE

28 VDC ~ 28 VDCCONTROLSWITCH

4- - - - - - - - - - - - - - - - - - - - - YAW PORT PRESSURE - - - - - - - - - - - - - - - - - - - - __

,-------. .. . - - - - - - - - - - - - - - - - - - - -STATIC PORT PRESSURE - - - - - - - - - - - - - - - - - - - r - - NO.1

.. . - - - - - - - - - - - - - - - - - - - - - PI TOT PRESSURE - - - - - - - - - - - - - - - - - - - - ....NO.2 -- SAS 28 VDC PRIMARY BUS SAS . -

0X 115 VAC PRIMARY 8US BOX

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CONTROL CONTROL .,,'"",,,,

." z VALVE CONTROL VALVE ~ ( i ) ~,,,, -'en~ ( i l NO.2

SWITCH NO.1..

.. " ..z"BOOST BOOST ", U ZUl l i

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SWITCH " 00' "

;OlD SWITCHU '"

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U ...Ju;0 .... l'! WARNING LIGHT WARNINr. LIGHT

NO.2 HYD BOOST OFF I NO.1 HYD BOOST OFFQ.

U!CONTROL CONTROL OJ

YAW SIGNALS

YAW FEEDBACK SIGNALS

2.6 VAC TO FEEDBACK EXCITATION

l 4 NO.1 YAW - ------ -

NO.1 PITCH NO.1 ROLL

'--- EXTENSIBLE EXTENSIBLE .-- EXTENSIBLELINK LINK LINK

NO.2 YAW +-- NO.2 PITCH N0 2 ROLL

EXTENSIBLE EXTENSIBLE ' - - - EXTENSIBLELINK LINK LINK

T r !PITCH SIGNALS

PI TCH FEEDBACK SI GNALS

ROLL SIGNALS

ROLL FEEDBACK SIGNALS

BLOCK DIAGRAM - SAS SYSTEM

1 '

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46

I'

1 I t a ~FAMILIARIZATION MANUAL

]) ..



STABILITY AUGMENTATION SYSTEM

The Stabil i ty Augmentat ion System (SAS) is

an electronic ra te sensing system which main

ta ins hel icopter stabi l i ty about the ro l l , pitch,

and yaw axes through independent posi t ioning

of the f l ight controls . This el iminates the

smal l correc t ive movement s normally required

by the pi lot to keep the hel icopter at the

des i red atti tude. In performing i ts ra te damp-

ing function, the SA S senses any abrupt move-

m e n t of th e helicopter an d immedia te ly r eac t s

to offse t i t . This instantaneous correc t ive

reac t ion tends to dampen any sudden motion o r

change of atti tude. The SA S has l imi ted au-

thori ty ( less than 50 percent) an d will induce

cor rec t ive action to the fl ight controls up to

that point . Any cor rec t ive act ion beyond th is

l imi t mus t be induced by the pilot . The pilot

re ta ins full control of th e helicopter an d can

over r ide th e SA S if he des i re s .

A ra te gyro, sensing a change in the heli

copter at t i tude, produces a s igna l which is

ampli f ied an d sen t to i ts respect ive extensible

link, causing i t to extend o r r e t r ac t , which r e

posi t ions th e ro ta ry - wing controls to counteract

the ini t ia l change in helicopter atti tude. A ll

th is act ion takes place without any movement

of the cockpit controls .

To ensure complete re l iabi l i ty , tw o ident icals tabi l i ty augmentat ion sys tems a re ins ta l led so

that no powe r fa i lure to on e electronic am -

plif ier or hydraul ic supply sys tem can cause a

lo ss of s tabi l i ty augmentat ion which cannot be

recovered by t r ans fe r r ing to the a l te rna te sys

t e m . The dual sys tem is designed so that

ei ther SA S can be used independent ly o r th e tw o

sys tems can be used together; in th e la t te r

case , each sys tem opera tes at half gain. When

both sys tems a re in use, a single powe r fa i lure

will be of l i t t le consequence to the pilot since

the operat ional SA S will automat ical ly switch

to full gain an d thereby continue to s tabi l ize the

helicopter .

Each SA S ampl i f ie r contains the ra te gyros,

channel ampl i f ie r s , an d circui t ry neces sa ry for

the operat ion of that system in control l ing ro l l ,

pitch, an d yaw axes . In addit ion, each SA S am -

plif ier contains in te rna l tes t c i rcui ts which

allow the checking of each channel (pi tch, ro l l

an d yaw) an d thus el iminates the neces si ty of

using outside tes t equipment .

Sidesl ipping of the helicopter is sensed from

por ts on th e forward fuselage. Dif ferent ia l

s idesl ip pres sure i s conver ted to an elec tr ica l

signal in the SA S amplif ier an d directed to the

yaw extensible l ink for s idesl ip correc t ions .

47

[ ,1 ! I a ~ FAMILIARIZATION MANUAL..



SAS SYSTEM ['

48

l

11

1 i I a ~ FAMILIARIZATION MANUAL..



LONGITUDINAL

CYCLIC TRIM

/

j(7JV

ACTUATOR

/f/l)) €J

OFWD AFT

EXTEND EXTEND~ ~ O

0l::I RETRACT RETRACT

'J!?MANUAL OPERATION

f/l)' LONG CYC TRIM

CYCLIC TRIM CONTROL PANEL

DCP

ACTUATOR

SPEED TRIM AMPLIFIER

SPEED TRIM SYSTEM

49

1 I a ~FAMILIARIZATION MANUAL..



2av DC

SECONDARY BUS

-SPEED TRIM PANEL

IMANUAL OPERATIONILONG. CYC TRIM

ISPEED TRIM IIAUTO I IMANI

FLCT AUTOMATIC TRIM EXTEND VOLTAGES

FLCT AUTOMATIC TRIM RETRACT VOLTAGES -ALCT AUTOMATIC TRIMEXTEND VOLTAGES

ALCT AUTOMATIC TRIMRETRACT VOLTAGES

EXCITATION

SPEED TRIM

AMPLIFIERACTUATOR POSITION SIGNAL

I EXCITATION

ACTUATOR POSITION SIGNAL

115VACSECONDARY

BUS

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•

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< to

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::JW<to::

FORWARD

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: :JX<tw

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, •

! 1

LONGITUDINAL LONGITUDINALPITOTCYCLIC TRIM CYCLIC TRIMAND : (FLCT) ACTUATOR (ALCT ) ACTUATORTATIC

AIR PRESSURE

i

EXCITATIONTRIM

BIAS VOLTAGE WHEEL

AFT

EXCITATIONSPEED

ACTUATOR POSITION SIGNAL TRIM

EXTEND AND RETRACT VOLTAGES ACTUATOR

EXCITATIONSTICK

ACTUATOR POSITION SIGNAL TRIMEXTEND AND RETRACT VOLTAGES ACTUATOR

BLOCK DIAGRAM· SPEED TRIM SYSTEM

50

D a ~'t ... FAMILIARIZATION MANU AL



SPEED TRIM SYSTEM

The Speed Tr im is an electronic a r range m e n t which main ta ins a l eve l fuselage over a

wide range of forward a i r speeds while pro

viding positive st ick gradient . I t also al lows

the pilot to maintain a comfor table s t ick posi

t ion during adverse cen te r of gravity condi t ions.

The system conver t s airspeed i n fo rmat ion

from the pi tot- s ta t ic system to an elec tr ica l

signal which controls e lec t romechan ica l actu

a tor s in the f l ight con t ro l sys tem. The actua tor s vary th e dif ferent ia l col lect ive pitch of

the blades an d the plane of rotat ion of the

ro ta ry - wing heads. The pi lot controls the

mode of operat ion {m.anual o r automatic} through

the use of se lec to r swi t ches .

A s t ick t r im wheel in the cockpi t se rves to

e lec t r ica l ly re - r ig th e control system an d

reposi t ion th e cyclic st ick to maintain a neu t ra l

longi tudina l pos i t ion.

The longi tudina l cycl ic t r im ac tua to rs , on e ateach upper ro to r con t ro l a ssembly , conver t

elec tr ica l signals to mechan ica l movement to

change the angle of at tack or at t i tude of th e

blades. Two cycl ic indicators a re included in

th e cockpi t in s t rumen ta t ion to display the posi

t ion of these ac tua to rs .

The DC P actuator is located in the f l ight

con t ro ls compar tmen t between sta t ions 95.00 an d

120.00, an d cons is t s of tw o independent actua to rs connected by an aluminum tube. The

upper actuator is control led e lec t r ica l ly by the

speed t r im ampl i f ie r to program cor rec t ive

motion to the fl ight controls in or de r to main

ta in a posi t ive st ick gradient .

The l ower actuator is control led e lec t r ica l ly

by the t r im wheel . I t r e - r i g s the fl ight con

t ro l s pitch system to main ta in a comfor t ab le

s t ick posi t ion.

51

m r a ~fAMILIARIZATION MANUAL.. [ .



DUAL

ACTUATING

CYLINDER

STICK BOOST

/.

DUAL

EXTENSIBLE

LINK

FLT

HYO.BST SAS

C NQ.2 ON NO.2 ONCONTROL

CENTER

N0

@OFF @ B g ~ H @ T

ON NO.1 ON NO.1 ON

iii)) @ @ (0

FLIGHT CONTROL PANEL

MENGAG E

URE LEASE

EMER SAS REL

@ @

0 " - - - f@

EMERGENCY SASRELEASE

DUAL

ACTUATING

CYLINDER

FLIGHT CONTROL HYDRAULIC SYSTEM

52

. . ~ AMILIARIZATION MANUAL]) ..



FLIGHT CONTROL HYDRAULIC SYSTEM

The f l ight control hydraul ic system consis ts

of tw o identic al but independent sys tems: fl ight

control system No. 1 an d f l ight control system

N o . 2 . Each sys tem conta ins i ts own hydraul ic

t ank, pump, an d plumbing instal la t ion, along

with th e necessa ry valves , f i l te rs , an d fi t t ings

that a re required to complete th e sys tem. Each

system suppl ies hydraul ic pressure to operate

th e forward an d aft pivoting an d swiveling dual

actuat ing-cylinders , the Stabi l i ty Augmenta t ion

System (SAS) dual extensible l inks, an d the dua lst ick- boost ac tua to rs .

In each sys tem, hydraul ic fluid f rom th e tank

i s gravi ty fe d to th e pump where th e fluid is

pressur ized to 3,000 psi an d then is d irected

to the flight control manifold. In the manifold,

fluid passes through a f i l ter to a pressure re

l ief valve an d a solenoid- operated con trol valve.

Fluid f rom the mani fold is directed to the aft

pivoting an d swiveling dual actuat ing-cylindersan d through a f i l te r to th e forward swiveling

and pivoting dual actuat ing-cylinders . At th e

same t ime i t is directed to a 1,500 psi pres

su re reducer . The reduced pressure is di

rected through a f i l ter to the SA S solenoid

control valves and, a t th e same t ime, to th e

dual s t ick-boost actuat ing-cyl inder manifolds

wher e pas sages dir ect th e fluid to th e ac tu

at ing-cylinders . When ei ther No. 1 or N o . 2

SA S is selected, th e re la ted SA S solenoid con

t ro l valve is open an d the fluid is directed to

the dual extensible l inks; if BOTH i s selected,

both control valves a re open. The fluid is

re turned f rom the dua l actuat ing-cylinders

through a f i l ter to the hydraul ic tank. The

pivoting and swiveling dual actuat ing-cylinders

an d the dua l s t i ck -boos t actuators a re capable

of normal operat ion even when powered by

only one hydraul ic sys tem. The dual extensible

l inks consis t of two actuators which a re bolted

together , en d to end. The No. 1 hydraul ic

system supplies fluid to the l ower actuators

of the dual extensible l inks an d th e No. 2 sys

tem suppl ies fluid to the upper ac tua to rs .

When both hydraul ic sys tems a re functioning,

each actuator of a dual extensible l ink providesone- half of the to tal mot ion requ i red . I f one

hydraul ic system fa i l s , th e affected actuator

locks in a f ixed d imens ion . The other actuator

will then automat ical ly provide the full motion

requ i red .

53

- ~ . FAMILIARIZATION MANUAL



FLIGHT PRINCIPLES

The hel icopter differ s from. the f ixed-wing To equal ize the l i ft through out the cycle, the [ I

a i rc ra f t in that i t s l i ft ing surfaces ro ta te . In blades a re perm.i t ted to f lap . The advancing

the CH-47, l if t and propulsion a re der ived f rom blade f laps upward because of inc reased lift;

tw o ro t a ry -wing heads each with th ree blades, th e re treat ing blade f laps downward because of

one l oca ted fo rward and th e other aft . Since decreased l i ft . The resul t ing re la t ive wind

t hese he a ds ro ta te in opposi te direct ion, torque causes a reduct ion in angle of at tack of th e

is cancel led out, and no anti- torque rotor is advancing blade and an inc rease in angle of

requ i r ed. The CH-47 blade cyc le i l lu s t ra te s at tack of th e re t rea t ing blade . In this way l i ft

how a ful ly art icula ted ro t a ry -wing sys tem. m.ain is equal ized ac ross th e ro t a ry -wing disk.

ta ins sym.m.etr ic lift. In fo rward fl ight d is

sym.m.etry of l i ft is caused by th e re la t ive wind, The cycle of a single fo rward blade with

which acts as a head wind on the advancing counterclockwise rotat ion is i l lus tra ted . The

blade and inc reases the l i ft , while i t acts as a sam.e cycle oC,curs with the aft blade, except

ta i l wind on a re t rea t ing blade and decreases tha t rotat ion is c lockwise which r eve r ses th e0 0

th e lift. 90 and 27 0 posi t ions in th e cycle .

DIRECTION OF

HELICOPTERAXIS OF ~

AXIMUM RELATIVE MOVEMENTROTATION

VELOCITY (FORWARD FLIGHT)

MINIMUM A N G L E ~ OF ATTACK 90 0

ADVANCING _ LOWEST FLAP

BLADE POINT

HIGHEST FLAPPOINT

2700~ MINIMUM RELATIVE

TRUE VERTICAL VELOCITY lAXIMUM ANGLE

BLADEOF ATTACK

54t

1 i I a ~ FAMILIARIZATION MANUAL.



Hinge Points

Aful ly a r t icu la ted blade assembly i s capable

of movement in three direct ions about its a t

t achment to the ro tary-wing head: up and down

(flap) through a hor izontal hinge pin, side to

side (lead and lag) through a ver t ica l hinge pin,

and rotat ing (t o increase or dec rease pitch)

through th e laminated t ie bar s within the pi tch

varying housing to which th e blade assembly i s

at tached.

Lead-lag movement s and flapping a re causedby external aerodynamic fo rces prevai l ing in

th e ro ta ry -wing plane of ro ta t ion and a re be

yond th e pilot s control . Pitch changes a re

control led by th e pilot, ei ther col lect ively to

vary the l i ft or cycl ical ly to vary th e fl ight

d ir ect ion.

VERTICAL PIN

Control Actions

The CH-47 has three basic pilot fl ight cont rols : direct ional peda l s , pi tch an d rol l control

st ick, and th rus t control . The f ir s t tw o con

t rols a re posi t ioned sim.i1arly to those in f ixed

wing aircraf t , while th e la t te r is located to th e

left of each pilo t 's sea t . A br ie f explanat ion of

th e hel icopter control act ions fol lows.

Flight con trol movem ents a re t ransmi t ted

through a system of be l lc ranks , push-pu l l tubes,

an d a mixing unit . Control movements are

mixed to become l a t e ra l cyclic an d col lect ive

pitch motions to th e hydraul ic actuators in the

upper controls .

These controls t i l t swashplates in th e ro ta ry

wing controls , which, in turn, r a i s e or lower

pi tch l inks. The pi tch l inks vary th e pi tch of

th e ro ta ry -wing blades during th e ro ta t ion cycle.

Coordinat ion of controls to produce var ious

fl ight maneuvers

is cus tomary , as in f ixedwing a i rc ra f t . However , it mus t be r e me mbe r e d

tha t hel icopter control act ions have their ow n

character is t ic effec t s on a ir craf t at t i tude, an d

tha t an addi t iona l control, th e th rus t control,

m u s t be coordinated fo r ce r ta in maneuvers . A

cl imbing turn, for i n s t ance , i s accompl i shed by

use of direct ional pedal , af t control s tick , and

increased th rus t .

55

1 ! I a ~ .... FAMILIARIZATION MANUAL



o 0

Control Stick (Stick Forward Shown)

F o r fo rward f light, the p i lo t moves the con-

t ro l stick forward; th e thrus t of th e aft ro ta ry

wing is inc reased while th e th rus t of th e forward

ro ta ry wing is decreased, causing th e hel icopter

to move forward. Since the re is a large range

of longitudinal control , high fo rward speed and

ex t remes in cen te r -o f -g rav i ty t ravel a re in

herent .

When th e pi lot wishes to move la tera l ly or to

rol l to th e left or r ight , he mo v es th e control

stick in the des i red direct ion; this act ion tilts

the plane of ro ta t ion of both ro ta ry wings in the

same dir ection, causing a corresponding move-

ment of th e helicopter .

[ i

Thrust Control (Increased Thrust Shown) I 'To produce cl imbs o r descen t s , l i ft can be

var ied by changing th e th rus t of th e ro ta ry

wings. When the th rus t control in the cockpit

is ra i sed , the pi tch of a ll s ix ro tary-wing blades

is inc reased s imultaneous ly and causes th e heli

copter to ascend. Lowering the th rus t control

dec reases the pi tch of a ll six ro tary-wing

blades , causing the hel icopter to des cend. An

in termediate setting of th e thrus t control pe r

mits a des i red al t i tude to be maintained.

Autorotat ion is accomplished, without engine

power, by lowering the th rus t control an d

mainta in ing s l igh t forward motion to the landing

s i te .

l56

l'

- ~ FAMILIARIZATION MANUAL



Directional Control(Left Pedal

Application Shown)

Direc t iona l control i s achieved by t i l t ing the

plane of ro ta t ion of th e ro ta ry wings . Control

mot ions to accomplish this a re impar ted by th e

control st ick or th e direct ional pedals , or both.

Since the l if t of th e ro tary-wing blades is in

c reased through par t of th e cycle and decreased

through another par t of the cycle, the plane of

ro ta t ion i s t i l ted . As th e ro ta t ion plane t i l ts ,

th e hel icopter moves in th e direct ion of th e

downward side of th e t i l t .

When the pilot applies d ir ect ional pedal move-

m e n t in one d ir ect ion, th e plane of ro ta t ion of

the fo rward ro ta ry wing is tilted downward in

th e same direct ion; simul taneously , th e plane

of ro ta t ion of the aft ro ta ry wing is t i l ted down-

ward in the opposi te direct ion. The r e sul t is a

hover ing turn around th e ver t ica l axis .

<JfO"v v v v v 0<( i,( i I.........~

Automatic Speed Trim

Increasing a ir speed c rea tes an electronic

signal in th e automat ic speed t r im sys tem to

provide longi tudina l cyclic t i l t of th e ro ta ry

wings . This system automat ical ly adjusts th e

t i l t of both ro ta ry wings to a substant ia l ly level

fuselage atti tude a t high speed. Increasing a ir

speed also provides programmed l' emoval of

som,= dif ferent ia l col lect ive pi tch induced with

the control stick, thereby providing a posi t ive

st ick gradient .

I f a i r speed i s constant an d th e helicopter is

momenta r i ly displaced longitudinal ly by gusty

winds causing an a i r speed change , the speed

t r im system will tend to r e turn th e helicopter

to th e selected speed.

57

- ~AMILIARIZATION MANUAL..



UTILITYSUBSYSTEMS

CARGO RAMP AND DOOR

CARGO/RESCUE WINCH

CARGO HOOK RELEASEWHEEL BRAKES (FWD & AFT)SWIVEL LOCKS

POWER STEERINGAFT LANDING GEAR CENTERINGROTOR BRA KES

NO.1ENGINE

START MOTOR

ENGINE

STARTVALVE

NO.2ENGINE

START MOTOR

ACCESSORYTILITYSYSTEM GEAR

PUMP BOX

AGBMOTOR

IUTILITYSYSTEM AFTPRAGUERESSURE ~ .....~ TRANSMISSION

LUTCHEDUCERALVE

HANDPUMP

~ if ,

rACCUMULATOR

I~ APU

MOTOR- APUPUMP

( ,STARTVALVE

--..

f 'UTILITY HYDRAULIC SYSTEM

53

d I a ~} FAMILIARIZATION MANUAL.



UTILITY HYDRAULIC SYSTEM

The ut i l i ty hydraul ic system consists of anengine s tar t ing and hydraul ic power system and

subsys tems . T he subsys tems consis t of a r amp

actuat ing sys t em, a wheel brake sys tem, a

ca rgo/ re scue winch, a cargo hook r e lease sys

t em, and a power s teer ing system. The engine

s tar t ing and hydraul ic power system supplies

hydraul ic f luid at 4000 ps i fo r engine s tar t ing

and a t 3000 psi for the subsys tems .

An acces so rygear

box, driven by the aft

t r ansmiss ion , d r ives th e utili ty hydraul ic sys tem pump to pressur ize th e sys tem. A I -way

dr ive, overrunning (sprag- type) clutch, ins ta l led

in the aft t r ansmis sion, permi ts independent

operat ion of th e accessory gear box i f the aft

t r ansmis sion is not operat ing. The auxil iary

power unit (APU) can be used to supply power to

drive th e accessor ie s . An APU-dr iven m o t o r

pump suppl ies hydraul ic pr e s s u r e to drive a

motor on th e acces so ry gea r box which, in tu rn ,

rota tes th e accessory dr ives .

59



/

\

\

1 - ~. FAMILIARIZATION MANUAL}



UTILITY HYDRAULIC SUBSYSTEMS

The cargo r a mp is operated hydraul ical ly .The r a m p can be stopped and held at any in te r

media te posi t ion . A r e t r ac table door is an

in teg ra l par t of th e ramp . When th e r a m p i s

being lowered , a sequence va lve causes th e door

to r e t r ac t into the r a m p automatical ly . When

th e r a m p is being ra i sed , the valve causes th e

door to extend. A manual ly control led locking

pin on the sequence va lve permi t s th e r amp to

be r a i sed and lowered with the door fully r e

t r ac ted . The r a m p can also be operated when

normal sys tem pres su re is not avai lable by

pr es suriz ing th e sys tem accumula to r with th e

hand pump.

The fo rward an d aft wheel brakes a re oper

ated s imultaneous ly when th e aft landing gear

is centered, swivel locks engaged, and th e brake

pedals depr es sed . The fo rward wheel brakes

a re operated independently when th e aft landing

gear is no t centered and locked.

Aft landing gear center ing is accompl i shed

hydraul ical ly when swivels a re locked. Pa r k

brakes a re applied to the fo rward wheels and tothe aft wheels when th e above condit ions a re

met . The pi lot and copilot mas te r cyl inder s a r e

iso la ted

va lves .

f rom each other by brake t ransfer

The

dr iven,

ca rgo/ r

level

e s c ue

winding

winch

r ee l

is a

with

hyd

an

raul ical ly

automatic

brake. The brake i s re leased hydraul ical ly

when winch operat ion is s elec ted . Winch speed

and dir ection is control led by a proport ional

solenoid valve and rheos ta t s at th e pilo t 's con-

t ro l panel and ho i s t opera tor ' s posi t ion. Maxi-

m um "ree l -ou t" speed is l imitec by flow-

regulat ion.

The external cargo hook is normally r e leased

hydraul ical ly and reengaged pneumatical ly . I futi l i ty hydraul ic pres su re should fai l , the hook

can be re leased pneumatical ly . An emergency

" ma nua l " r e l e a se is a lso provided on th e cargo

hook assembly .

61

r ililJ ED

a r a ~... { FAMILIARIZATION MANUAL



(MANUAL)

®

HOIST CONTROL

PANEL

CABLE HOOK AND

QUICK DISCONNECT

WINCH CONTROL

GRIP

o 0

e

$ ..

e

.. ":::,::0'"of r l

H O f : ~ K ( "@OfrMOM OM

(j i

{

{ ,

WINCH

EMERGENCYRELEASE I \

\

o

~ C A B L E~ C U T T E R

~

o HOIST

MASTERREMOTE

@ OFF

PILOT

EMERGENCY MASTER

@Ijl OFF @ OFF

RELEASE ARM ~ ~ L C A R G O HOOK J 'W

HOIST CONTROL PANEL

0) HOIST CONTROL

OFF

OUT

qj\IN

o

CARGO HOIST SYSTEM

CARGO HOOK

{'

L62

l

1 ! I a ~... FAMILIARIZATION MANUAL}

!ll5AFT WHEELS ~

SWIVELRELEASE

CAUTION

LIGHTS 9/)



! @:

SWIVEL LOCK

BRAKES ~ PRIMER W

®B @ ) T ~ TS

IM

9/)

SWIVEL LOCK

CONTROL PANEL

MASTER BRAKE

CYLINDERS SWIVEL}LOCK

@ @ON PWR STEERING C O ~ @OFF ~ \JO

\ I

AFT LANDING GEAR

@ o @

POWER STEERING CONTROL PANEL

SWIVEL LOCK, POWER STEERING AND WHEEL BRAKES

63

1 I F a ~FAMILIARIZATION MANUAL. {



{ ,

AC AND DC EQUIPMENT

AC AND DC ELECTRICAL SYSTEM

64

1.

1

}-

1 ! I I a ~FAMILIARIZATION MANUAL.



\J

The pr i ma r y source of elec tr ic power for this

helicopter is an ac generat ing system. Two ac

generators (a l ternators) a re driven by th e ac

cessory gear box on the aft t r ansmiss ion . Each

produces 120/208-vol t , 3-phase , 400-cycle c ur

ren t ; one ( No . 1 ) generator suppl ies power to

:p r imary buses and the o ther (No .2 ) generator

suppl ies power to secondary buses . An auxil iary

bus is connected to th e pr i ma r y bus th rough a

bus- t ie re lay . The pr imary and secondary buses

a re separa ted e lec t r ica l ly by the open contacts

of another bus ..t ie re lay; i f ei ther generator

fa i l s , this re lay closes automat ical ly to connect

both th e pr i ma r y and secondary buses to th e

operat ing genera to r to ensure continuous oper

at ion of a l l ac equipment. A caution l ight warns

the pi lot whenever a generator becomes inoper

at ive.

The ac sys tem is protected f rom overvol tage ,

undervol tage , and underf requency condit ions by

a generator protect ion panel . During engine

s tar t ing, th e No. 2 generator is disconnected

automatical ly to reduce th e s tar t ing load on th e

auxil iary power uni t . Two ac loadmeter s lo

cated on th e cen te r sect ion of th e in s t rumen t

panel indicates generator output re la t ive to the

ra ted load .

AC-DC ELECTRICAL SYSTEMS

Two t r ans former - rec t i f i e r s located in the

fo rward sect ion of th e lef t -hand pod supply 28

volt dc. Direc t cur rent is also supplied by a

24-vol t nickel-cadmium battery . Dc power i s

supplied f rom one (No.1) t r ans former - r ec t i f ie r

to a pr imary bus and from th e other (No .2 )

t r ans former - rec t i f i e r to a secondary bus. A

bus- t ie re lay is located between the pr i ma r y

and secondary buses . I f ei ther t r a ns f o r me r

rec t i f ier fails , th e re lay closes to connect the

tw o buses ; this ensures continuous operat ion of

a l l dc equipment. In addit ion, a radio bus and

an e m e r gency bus a r e connected to the pr i ma r y

bus thru a bus- t ie re lay and an emergency bus

re lay , respect ively . The emergency bus can be

connected direct ly to th e battery th rough th e

e m e r gency bus re lay . A caution light on th e

console warns th e pilot i f a t r ans fo rmer - r ec t i

f ie r becomes inoperat ive.

Both ac and dc can be supplied to the he l i

copter th rough ex te rna l power recep tac les . I fonly ac external p o w er is uti l ized, dc power is

supplied by th e helicopter t r a n s f o r m e r - r ~ c t i f i e r s . I f both ac and dc external power is used ,

th e t r ans former - r ect if ier s a re automat ical ly

dis connected f rom th e circuit . I f only dc ex

te rnal power is avai lable, th e ins ta l led apu must

be operated to obtain ac power.

65

1 'a r r a ~ ( \.. \AMILIARIZATION MANUAL

CIRCUIT BREAKER

SECTION 1:



~ OVERHEAD~ SWITCH PANEL 1

COPILOT'S

INSTRUMENT

PANEL {

TYPICAL OVERHEAD SWITCH PANEL

COPILOT'S ~ I.I

ICYCLIC -

STICK

PILOT'S

INSTRUMENT { ,PANEL

COPILOT'S BRAKESEAT PEDAL

UPPERDIRECTIONAL

CONSOLEPEDAL

CENTER PILOT'S

CONSOLE CYCLIC

STICK

:

t:

66

l'

PILOT'S

THRUST

CONTROL

TYPICAL COCKPIT

1

), FAMILIARIZATION MANU AL

D a ~..

COCKPIT ARRANGEMENT



Basic hel icopter miss ions , operat ional com

mitmen ts and varied sub system insta l la t ions

m ay al ter th e specific combinat ions of cockpit

equipment . However , a typical a r rangement of

sys tems controls plus s tandard fl ight and non

fl ight ins trumentat ions will be found in m o s t

CH-47 helicopters .

A three-sect ion in s t rumen t panel is located

on th e fo rward en d of the console. The center

sect ion contains engine, t r ansmiss ion , fuel,

hydraul ic , elec tr ica l and cycl ic t r im ins t ru

ments which a re shared by both the pilot and

the copilot . The engine fi r e warning l ights

} and fire control handles a re located at the top

of this sect ion. The pilot sect ion (r ight) and

copilot sect ion (left) contain dual indicators fo r

ro tor rpm, engine to rque , a ir speed, alt i tude,

at t i tude, ver t ica l velocity, heading, and o ther

navigation.

There a re th ree single ins ta l la t ion control

panels which a r e sha r ed by both pi lots : the

upper console, the lower console and th e over

head control panel . The overhead control panel

contains a c i rcu i t b reaker sect ion in addit ion

to elec tr ica l controls for l ighting, heating,

hois t and hook, APU, engine fuel, elec tr ica l

and hydraul ic sys tems .

Subsystem caution l ights, th e cyclic stick

control and navigational equipment controls a re

mounted on th e upper console .

The lower console is situated between the

pilo ts ' seats and contains contr ols for engine

condition, cyclic t r im, power s teer ing SA S and

swivel locks . The luajor por t ion of th e console

is occupied by communicat ion and navigation

equipment which inc ludes in terphone, F M l ia i

son, A F, VHF and UH F radio, emergency VHF

t r ansmi t t e r , direct ion f inding, range bear ing

and identificat ion.

67

FAMILIARIZATION MANUAL~.. {:

/ ~ ~ - - \ \ \ 1:H



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CABIN DUCTING

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1

1 I r a ~} ... FAMILIARIZATION MANUAL

HEATING AND VENTILATION SYSTEM



T he he l icop te r ' s heat ing and venti lat ing sys tem provides e i ther hea ted or unheated vent i

la t ing a i r to the cabin and cockpi t a reas . T he

sys tem inc ludes a 200,000 BTU/hr -capac i ty

c ombus t i on- t ype hea te r , a blower , ducting, and

control and regulat ing equipment . F u e l to oper

ate the hea te r is obtained f rom the lef t -hand

fuel tank.

T he hea te r and the b lower a r e mounted ve r

t ical ly on the r igh t -hands ide

of the hel icopterd i r ec t ly a ft of the cockpi t bulkhead. The hea te r

cons i s t s of an outer tube and j acke t a s sembly in

which an inner combus t ion tube is posi t ioned

concentr ical ly .

.}To prov i de the sys tem's a i r supply, the

blower dra ws a ir from a sc reened opening lo

cated on the fo rward upper cabin sec t ion. T he

a i r i s fo r ced through th e hea te r where i t i s

channeled into vent i l a t ing- and c ombus t i on- t ype

a i r . A vapor i zed fue l -a i r mixtu r e is igni t ed a nd

burned in the combust ion tube. Vent i la t ing a i r

p a s s e s over the heated combust ion tube and, in

turn , becomes hea ted. It then en te r s the duc t

in g network. Combus t ion gasses a re d i scharged

through an exhaus t out le t .

When the sys t em is used ent i re ly for vent i la t ing , combust ion does not oc c ur . In th i s case,

outs ide a ir i s forced through th e sys t em along

the same rou te .

During the heat ing opera t ion, a pro tec t ive

sys tem i s provided by four switches. T h r e e

t h e r m a l swi tches a r e used for over tempera tu re

pro tec t ion and a cycling function; a diff e r ent ia l

pr e s s u r e swi tch i s used to stop hea te r oper

a t ion i f the re i s insuff ic ient a ir fo r the hea te rto funct ion proper ly .

T he cabin t empera tu re is automat ical ly con-

t ro l led by th e mode se lec t ing switch and the

hea te r s ta r t switch , located on the overhead

swi tch pane l in the cockpi t , the t empera tu re

con t ro l l e r in th e hea te r compar tmen t , the t e m

pera tu re se lec to r on the overhead swi tch panel ,

and the cabin the rmos ta t on the lef t -hand s ide

ofthe cockpi t

entranceway.

Cont rol handles , located in the cockpi t , pe r

m it the select ion of ai r f low rout ing and de

fogging or def rost ing of the cockpit enc losure .

Four teen manual ly adjustable out le t s a re p r o

vided in the cabin fuselage sec t ion.

69

{1 I a ~FAMILIARIZATION MANUAL.. {

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TIEDOWN FITTINGS AND PULLEY ARRANGEMENT

CARGO/RESCUE OPERATION I

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- . a ~ FAMILIARIZATION MANUAl.

t CARGO /RESCUE



The pr i ma r y pa r t of this sys tem is th e hy

draulical ly operated winch, control led by ei ther

a c rewman in the cabin or th e pilot . The winch

uti l izes a 2- speed gear t ra in to provide a slow

r e t r i eva l r a t e for cargo handling and a m o r e

rap id r a te for r e scue operat ions. An over load

device automat ical ly stops the winch before a

snagged lead can break the cable .

Pulley blocks a re provided which can be a t

tached to the cargo t iedowns to reeve th e cable

over the f loor a t any des i red l a t e ra l location,for winching ca r go into or out of th e a i rc ra f t

th rough th e r amp and the door.

F o r re scue operat ions, the cable is reeved

u p w ard at s tat ion 120.00, along the overhead to

th e r e scue hatch, and then down th rough th e

hatch. The pulley block dir ectly over the hatch

i s equipped with an explosive ca r t r idge -ac tua ted

cable cut ter for emergency us e.

A l imi t swi tch in terconnected to th e oper

a tor ' s s tat ion controls plug stops the winch

when th e hook near s the cei l ing pulley. Con

t rols fo r th e winch and the cable cutter a re

located in the cockpit and at the ha tch .

The main cabin floor is designed fo r a dis

tr ibuted cargo load of 300 pounds per square

foot and a concen t r a t ed load of 1, 00 0 pounds

per wheel in th e center sec t ion . The outboard

port ion of th e floor, o r the t readway, is des igned for a 2,SOO-pound wheel load. Vehicles

can easi ly be dr iven in and out of the hel icopter

within these des ignated a reas .

The f loor contains eighty- seven S, 00 0 -pound

t iedown fi t t ings and eight 10,000-pound fi t t ings.

There a re also four S,OOO-pound fi t t ings on th e

loading r a m p .

I 71



. . ~.. FAMILIARIZATION MANUAL

ARMED CH-47



Severa l CH-47 helicopters have beenm.odified

to provide f i re suppor t capabi l i ty . The m.ission

ro le of the "Arm.ed Chinook" is to neutra l ize

enem.y ground f i re in a landing assau l t a rea

pr io r to th e a r r iva l of t r anspor t t roop ca r r i e r s .

The arm.ed ver s ions of th e CH-47 consis t of a

s tandard a i rc ra f t with vi tal system. dualizat ion,

over a ton of ins ta l led arm.or and extensive

a r r ay of weapons system.s.

Certa in item.s no t required for f i re suppor t

m.issions have been rem.oved, including the

auxil iary loading ram.ps, ca r go door , heater ,

sound proofing, winch, hook and all but five 1

m.an t roop sea ts .

Modificat ions include th e addit ion of a com.bat

in ter phone system., fuel f i re suppression pro

visions, tw o c ross feed fuel shutoff valves and

ball is t ic arm.or plat ing of th e pilo t 's seat and

vi tal a reas of the fl ight controls and dr ive sys

tem.s to withs tand .5 0 cal iber a m.m.uniti on, pr o

viding a high degree of survivabi l i ty fo r th e a i r

craf t .

Select ion of weapons system.s is based on

range, fragm.entat ion and r a te -of - f i r e . Severa l

cockpi t opera ted weapons which m.ay be ins ta l led

inc lude an M -5 40m.m. Grenade Launcher lo

cated in a rotat ing nose pod, XM-18 7.62m.m.

Machine Gun Pods , XM-159 2.75- inch Rocket

Launcher Pods or M-24 A l 20m.m. Autom.atic

Guns, any of which a re located on weapons

pylons on ei ther side of th e air craf t .

. The flanks of th e a i rc ra f t a re protected by

four gunners s ta t ioned in tw o windows on each

side of the cabin a rea . Each gunner is equipped

with ei ther an AM-M2 .50 cal iber or KM-60D

7.62m.m. Machine Gun on a f lexible m.ount.

Another gunner with a sim.i lar weapon i s s ta

t ioned aft on th e r e a r loading ram.p to pro tec t

th e a i rc ra f t during depar tu re from. the assaul t

a rea . The' Arm.ed Chinook" car r ies m.ore

than a to n of expendable m.unitions.

73



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chinook familiarization manual

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