Textron Cessna - Page 22

McCAULEYPROPELLERSYSTEMS
CONSTANTSPEEDCOMPOSITEOWNER/OPERATOR
INFORMATIONMANUAL
CONSTANTSPEEDPROPELLERSYSTEMDESCRIPTIONANDOPERATINGPRINCIPLES
1.Reciprocating(Piston)EnginePropellers
A.TheMcCauley3400modelseriespropellerisaconstantspeedpropellerwithcompositepropeller
bladesandaconventionalaluminumpropellerhub.
(1)TheC3400Seriesisathree-bladeconstantspeedpropeller.(RefertoFigure1).
CAUTION:Donotusethepropellerbladesforpushingorpullingor
maneuveringanairplaneontheground.Damagemayresultto
thepropellermechanismwhichmaynotbediscerniblebyexternal
visualexaminationofthepropeller.
B.Eachpropellerconsistsofahubassembly,compositepropellerblades,pistonandcylinderassembly.
C.DescriptionofthePropellerAssemblyComponents:
(1)PropellerHubAssembly-Thepropellerhubisasinglepiece,hollowassemblywithpropeller
bladesockets.EachbladesockettobladeshankisO-ringsealedtopreventleakage.Therear
hubfacehasthreadedstudsforattachmenttotheengineange.Therearhubfacealsohas
dowelsthatmatewithholesinthehubforalignment.Theseensurepropermountingtothe
enginepropellershaftange.
(2)PropellerBlades-Thepropellerbladesaremadeofacompositeberglass/carbonber
compositematerialaroundfoamcores.Eachpropellerbladeismatch-balancedtotheother
bladeswithinthepropellerassembly.
(a)Theentirepropellerassemblyisstaticbalancedaswell,usingbalanceweightsmounted
withscrewstothecylinderbalancering.
(3)BladeRetention-Externalretainers(outsidethehub)secureseachbladefrommovinginboard
inthehubandaseriesofballbearingsandbearingracespreventthepropellerbladefrom
movingoutboardduringpropelleroperation.Duringpitchchange,eachbladerotatesaboutits
axisonabearingassembly.Anactuatingpinonthebladebuttisapartofthebladeassembly.
Theactuatingpinisdrivenbyabushingattachedtothepistoninsidethehubcavity.
(4)PistonandCylinderAssembly-Oilpressure,controlledbythepropellergovernor,andaninternal
springactonthepistontoprovidetheforcesnecessarytoaccomplishpropellerbladepitch
changes.Thecylinderismountedtothehubfacewithscrewsandissealedtopreventleakage.
(5)InternalLubrication-Thepropellerhubcontainsareddyedoil.Thehubcavityispartiallylled
withreddyedenginetypeoilwhichissealedinthehubandisolatedfromtheengineoil.This
oilprovideslubricationandcorrosionprotectiontobladebearingsandotherinternalparts.The
oilisdyedredtoaidinthetroubleshootingofsuspectedpropellerleaks.
NOTE:PeriodiceldmaintenanceofthislubricationisNOTnormallyrequired.
D.DescriptionofPistonEnginePropellerOperatingPrinciples
(1)TheC3400modelseriespropellerisaconstantspeedtype.Thepropelleractuationisasingle-
actingpistonandcylinderunitinwhichhydraulicpressureworksagainsttheforcesofsprings
andthenaturalcentrifugalmomentoftherotatingpropellerbladetoprovidethecorrectpitchfor
engineload.Hydraulicpressurecausesthebladestomovetowardhighpitch(decreasingRPM).
Thespringsandcentrifugalmomentscausethebladestomovetowardslowpitch(increasing
RPM).
E.PropellerDeice(RefertoFigure2)
NOTE:Refertotheairplaneserviceormaintenancemanualforamoredetaileddescriptionofthe
propellerdeicecomponents.
(1)Ifpropellerdeiceisinstalled,thecomponentsinclude:
•electricallyheatedrubberboots
•deiceharnesses
•slipringassembly
•deicetimer
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©McCauleyPropellerSystemsJan9/2017