Bengtson Company Albatros DVa 54" User manual

AlbatrosDVa54”
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
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AlbatrosDVa54”
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R/CScaleModelInstructions
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CONTACTINFORMATION
DesignedbyKurtBengtson
PrototypebyDaveOttney
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ManufacturedandDistributedby:
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BengtsonCompany
POBox51102
PacificGroveCA93950
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PhoneandFax:831‐393‐0991
e‐mail:[email protected]
www.aerodromerc.com

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Copyright©2005KurtBengtsonAllRightsReservedRev10/05
AlbatrosDVa
Thankyouforpurchasingthe54”AlbatrosDVamodelfor
electricflight.
THEMODEL
FinishedModelbyDaveOttney
AsemiscaleadaptationoftheAlbatrosDVa,thismodelis
designedtobeeasytobuildandexcitingtofly.
POWERSETUP
ThemodelispoweredbytheMega22/20/2withMEC
gearboxanda14x7prop.Batterypowerpackisa10cell
1700maHNicadsoranequivalentweightNimh
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SPECIFICATIONS
Morethan290lasercutparts
Scale:15%scale
Channels:R/E/A/T
Wingspan:54ʺ
WingArea:718sqin
Prop:14x7
Weight:4pounds10ozreadytofly
PowerSystem:Mega22/20/2w/MECGB
Wheels:balsaandplywoodwithNeoprenefoamtires
AirfoilType:flat‐bottomed
Spinner:builtupfoamandfiberglass
Decals:onwebsite
Covering:BalsaandLitespanorPolyspan
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FEATURES
 Balsaformerstringerandkeelconstruction
 Fuselageissheetedorplanked
 Removablewings
 Topandbottomwingalignmentisbuiltintomodel
 Scaledihedral,includesinwingailerons
 Removablelasercutbalsadummyengineandexhaust
manifoldincluded
 DummySpandaumachinegunkitsincluded
 LasercutIPstruts(canbeusedastemplatesforbassor
spruce)
 Lasercuttailpartsincluded
BUILDINGTHEMODEL
BeforeStarting
Anoteaboutthephotos:Thephotosweretakenofa
prototypeandthepartssuppliedmaylookslightly
differentfromthem.However,theconceptsillustrated
arethesame.
WINGS
WingConstruction
Pindown,overtheplan,thet/e,sparsandwingtip,
gluingasrequired.Addtheleadingedgestockafterthe
basicframeisdoneasthestockisinsertedinarotated
fashion.
Addthewingtipsandalignthefronttipalongthecenter
oftheleadingedge.Sandtheleadingedgestocktobe
roundedandmeettheribs.
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TopWingConstructionDetail
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LowerWingConstructionDetail
Scallopingispre‐setbythetopandbottomplytrailing
edgepartssupplied.

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AileronConstructionDetail
Theleadingedgeoftheaileronisroundedoverwith
sandpapertomaketheaileronmovablewithaminimum
gap.Thetrailingedgeofthewinginthatsectionisleft
flat.
IPstrutattachmentpointsaremadefromalaminationof
threeplywoodribs.Twoouter1/8”plyribsareattached
toa1/32”plycore.
Dubrolandinggearstrapsareusedtoserveasattachment
pointsandareepoxiedintotheslotsprovidedinthe1/32
plywood.
IPAttachmentassembly
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FUSELAGECONSTRUCTION
Thefuselageisofformerandkeelconstructionwithtwo
internalplyrisersthatservetofixthecabaneattachment
points,undercarriageattachmentpoints,motormount,
lowerwingandbatteryintoaunifiedstructure.
BuildingtheFuselage
Beginbybuildingleftfuselagesideframeovertheplan
includingthesidekeel.AddthefrontformerF2andthe
lastformerF7thenthesidekeel.Usingthesidekeel,the
otherformersareaddedaidingtheircorrectalignmentby
holdingthemtemporarilyinplace.
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LeftPlywoodRiserinPlace
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LeftFuselageConstructionDetail
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Finishingtheleftsideandstringers
Theframeisremovedfromthebuildingboard.Gluethe
rightsideF2andF7formercarefullyandaddthesidekeel
asbefore.Theformersaregluedtotheframeusingtheleft
sideasaguide.Besurethattheinternalplyrisersarein
placeearlyinthisstageofconstructionortherewillnotbe
roomtoaddthemlater.Theyarelabelledtoinsurethat
rightmotorthrustisbuiltintothefuselage.
Thedownthrustisalsobuiltinduetothetopandbottom
keels.AttachtheF1motormountformerandthefuselage
isreadyforthestringers.Attachstringersalternatelyleft
andrightinasymmetricalfashiontoavoidabanana
fuselage.Thestringersserveassupportforthe
sheeting/plankingprocess.

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FuselageReadyforStringers
1/16thbalsasheetingrequiredoverthestringers.Thebalsa
sheetsthatDaveusedintheprototypeprovedtobe
difficulttoconformtothecompoundshapeofthe
fuselage.Davegotaroundthisbyaddingadditional
stringers.Thereareplaceswherethestringersinterfere
withthecabaneandlowerwingplacement.Thisisnota
problemasafterthesheeting/plankingisapplied,theyare
superfluousanyway.Justcutthemoutasneeded.The
stringersarethereforsupportofthesheeting/planking
only.
Ifsheetingistobeusedandtoavoidthedifficultiesthat
Davehadinsheeting,choosethelightestbalsa.Cuttoa
roughshapeandsoakinhotwaterthenbindtothe
fuselagewithpapertowelandrubberbandsortapeand
letdry.Thisshouldsetacurveinthebalsa.
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FuselagewithStringers
Useblue/pinkStyrofoamforthetailendofthefuselage.
Sandthefoamtoshape.Ittoocanbecoveredinbalsa.
AddingtheUndercarriagemounts
UndercarriageMount
Theundercarriageismountedusingbrasstubingepoxied
intobasswoodmountedtocutoutsintheinternal
plywoodsides.
Note:Thekitnowcontainsasecond1/16”plywood
formertobelaminatedtothemotormount.
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MotorMountwBrassTubing
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TAILSURFACES
Layoutandgluepartsofthetailsurfacesontheplans.
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VerticalStabilizerandRubber
Theverticalstabilizercanbesheetedwith1/16thbalsa.
Sandthetailparts,roundingoffalledges.Don’taddthe
hornsorhingethesurfacesuntilaftercoveringis
complete.
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HorizontalStabilizerLaidOutOnPlans
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LANDINGGEAR
Thelandinggearismadefrom1/8”musicwireand
insertedintothebrasstubinginsidethefuselage.Bass
woodfairingssecurelyboundtotheuprightscanadd
significantstrength.Itisalsopossibletofashionashock‐
absorbingaxlebyaddingasecondaxleontopoftheone
thatsecurestheundercarriage.
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LandingGearDetail
Attachthesecondaxleinthecenterofbothaxleswith
wireandsolder.Thenuserubberbandsattheendswhere
thewheelsattachtoprovidetheshockresistanceforthe
freelymovingaxleandwheel(notshown).
DUMMYMOTOR
Assemblethedummymotorfromthebalsapartssupplied
andsandtoshape.Solid16gaugecopperelectricalwire
(blackinsulated)makesanexcellent“radiatorhose”.
Davefashionedahatchunderhisdummymotorfor
accesstohismotorandgearbox.Note:Thekitnow
includesaremovabledummyengineforadditionalaccess
tothefuselage.
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DummyMotor

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SpinnerComponents
Thespinneriscomposedoffiberglassedbluefoam.The
spinnerismadefrombluefoamwhichistackgluedtoa
pieceof1/32”ply.Epoxyashort1/4”diameterdowelto
thebackinthecenterofthedisk.
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Placetheassemblyinadrillchuckandsandthefoamto
shapewhileitspins.Glassthefoamusingstandard
glassingtechniques.
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Whentheepoxyisready,cuttheexcessfiberglassaway.
Thenremovetheplywoodandcarveoutthenecessary
recessforthepropeller.Drilloutthedowelonthe
plywooddisk.Gluethespinnertotheplywooddiskafter
thepropismountedtothemodel.Itshouldbeperfectly
alignedwiththefuselage.Itlookscomplicatedbutin
practicetheprocessgoeseasilyandworksverywell.
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Spinner
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COVERING
Anylightweightcoveringmaterialcanbeused.Polyspan
withdopeorMinwaxPolycrylicmakesagoodchoice.
Litespanisalsopopular.DaveOttneyusedLitespan.He
alsousedwater‐solublepolyurethanetosealandstainto
finishhisfuselage.
Decaloutlinesforthismodelareavailableon
www.aerodromerc.com/decalsinAdobeAcrobatpdf
formatforprintingondecalpaper.Contactpaperused
forkitchenshelfliningmakesexcellentdecals.Printout
thedecalonpaper,gluewithagluesticktothepaper
backingontheshelfpaper,cutthedecaloutwithan
Exactoknifeormicroscissors.Peeloffthepaperand
adheretoyourmodel.Useblackmaterialforthecrosses
andwhiteforthebackgrounds.
WHEELS
Gluingtheplysidesonthebalsacoremakesthebasisfor
thewheels.Usethebrasshubforalignment.Epoxythe
hubsinplaceandaddasufficientamountofepoxy
aroundthebaseofthehubtoreinforcetheconnectionof
thehubtotheply.Plywoodreinforcinghubsareprovided
thataretoslipoverthebrasstubingasshown.Next,CA
gluetheneoprenecordingtogethertofroma“tire”.Use
thinCAsparinglyastheCAbondsveryaggressivelyto
therubber.PresstheCAwettedendstogetherforan
instantbond.Thebestwaytoaligntheendsistoglue
themwhiletheyareinplaceonthewheel.Thenattachthe
tirestothewheelsandCAinplace.AthinbeadofCA
aroundtherimmakesforasecuretire.
Paperconesarecutout.Useaballpointpentoscoreeach
lineonthebacktomakeanimpressionof“spokes”Itis
helpfultodothisoperationonapapertabletsothatthe
penmakesagoodcrease.Foldthepaperalongthecrease
linestoexaggeratetheraisedlines.Oneofthesections
formingawedgeiscutout.Makecutstothecenterofthe
circlealongapairofthespokes.Closethepapercut‐out
toformaconeandtapethejointinsidethecone.
Theinsideconesmaynowbeattachedtothewheels.The
outsideconesmaybeattachedathispointifwheelcollars
aretobeused.Alternatively,afterinstallingthewheelson
thelandinggear,awashermaybesolderedtoholdthe
wheelinplaceandthentheconeisattached.Thismethod
makesaverynicescaleappearance.

WheelHubs

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INSTALLINGTHERADIOCONTROLGEAR
ServoBay
GettheR/Cgearfittedatthisstage,andalsothemotor.
AileronServos
Aileronservosaremountedinwingandattachedwith
shortthreadedrodstotheailerons.
BatteryTray
Afteralltheabovehasbeenplaced,mountthebattery
traymadefrom1/8”balsaandusethebatterypositionto
balancethemodelasshownontheplan.

BatteryPlacement







ASSEMBLY
Wing

Mounting/AligningBoltsonWingPanels
Thelowerwingisattachedtothefuselagethroughtwo8‐
32nylonboltsthatscrewintoblindnutsintheplyribs
locatedinthebottomwing.Thecabanestrutsaremade
from3/32”musicwireandareformedusingtheplywood
cabanestrutfairingasaguide.Aftersolderingthering
terminalsontheupperportionofthemusicwire,andfor
assembly,bindtheplyfairingtoreinforcethestruts.Use
thinCAtohardentheplywood.
IPstrutsaremadefromalaminationofthree‐plypieces.
Twoouter1/8”plysidesareattachedtoa1/32”plycore.
Small1/32”plyreinforcementsareaddedtotheends.
WingAttachmentConstructionDetail
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Dubrolandinggearstrapsareusedtoserveasattachment
pointsandareepoxiedintotheplyribsasdescribed
earlier.
SandIPStrutstoshapeandsecurewithnutsandbolts.
FittingTailSurfaces
Thehorizontalstabilizerisintwohalvesandhastabsthat
fitintoslotsinthesideofthefuselage.Insertthetwo
halves,anddryfittheelevatorusingCAhinges.The
elevatorservesasanalignmenttoolsothatthehorizontal
stabcanbeCAgluedinplace.Theverticalstabilizeralso
fitsintoaslotinthetopofthefuselageformedinF7.
AddingControlHornsonthePushrodEnds
Slipthecontrolhornsontothewirepushrodendsand,
withboththeservosandthecontrolsurfacescentered,
gluethehornsintotheirslots.

Pushrods
FittingtheRiggingWires
UsestrongthreadorKevlarfishinglineorelasticbeading
cordingtosimulateriggingwires.Usesmallscrews,
fishinghookeyes,straightpinheadsorsmalleyeletsto
attachthelines.These“wires”canaddadegreeof
strengthtoyourmodel.

WindsockDatafiles“AlbatrosFighters“publicationhas
detailsonplacementandmarkings.Availableat
http://www.aeroplanebooks.com/

Batteryhatch
Fashionabatteryhatchfromsoftbalsa.

BatteryHatchDetail
BalancingtheModel
Balancethemodelatthepointshown.Itisbesttoposition
thebatterytodothisoperation.

FLYING
ThemodelshouldROGongrass,pavementorhard
surfaces.Themodelmayrequirecoordinatedturnsusing
bothaileronsandruddercontrol.Thisisduetoadverse
yaw.Halvingtheailerondownthrowmayreducethis
tendency.Onesolutionisrotatingthecontrolarmofthe
aileronservoforwardabout20degrees.

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FinishedModelbyDaveOttney

Letthemodelgainaltitudeslowlyofftherunway.
Applyingtoomuchupelevatoratslowspeedsrisksa
stall.Makeyourturnsgentlyastightturnsrisktip
stallinginanymodel.Don’texpecttheelevatortomake
themodelclimb.Thinkoftheelevatorasadeviceto
changetheattitudeofthemodel.Thewingandairspeed
ultimatelymakethemodelclimb.Oftendownelevator
appliedatstallingcanavoidamajorcrash.Themost
importantdetailsforproperflightoperationsare:
1)CGlocation.Tailheavymodelsneverflywellorat
all.
2)Downandrightthrust
3)Straightandnonwarpedwings.

HerearesomeexcerptsofDaveʹsmaidenflights.
“Throttlingupitliftedoffinabout10ʹ!!Icouldnʹtbelieve
itjustkindofliftedoff,nothingradicalitwasjustairborne
allofasuddenkindoflevelandclimbingatashallow
rate.Ipowereduptofullthrottleandflewstraightout.It
neededabitofailerontrimandsomedowntrimtogetit
toflyabsolutelylevel.Speedswerescalelikeat1/2‐2/3
throttlewithonlyabitmorespeedwhenitwasfire
walled.Ithinkit’sjustadraggydesignsoit’snotgoingto
beaspeedster.Thefullthrottleperformancejustgivesit
ʺumphʺwhenneeded.

Ifoundaileronturnstohavesomeadverseyawinthatthe
taildroppedabitandyouhavetokindslogitthroughthe
turn.IwasfortunateinthatGaryAllen,apretty
renownedscalemodellerwhobelongstoourclub,
standingnearbygivingmesometipsonhowtodealwith
theadverseyaw.Ihadpre‐programmedsome
rudder/aileronmixinontheradiobutthesettingwasnʹt
rightsoIturnedthatoffanddidcoordinatedturns
manually.IdidfindthatIhadtogiveitabitofthrottle
throughtheturnsandthenwouldthrottlebackfor
straightflight.DuringacoupleofcircuitsIfoundthat
purerudderturnswiththeappropriateelevatorinput
madeforverysmoothturns.
Itookituphigherandthrottledbackapplyingfullupto
seewhatthestallwouldbe.Oneshutterandit“mushed”
straightforwardregainingspeedandlift.Ikindoffigured
itwouldbelikethat,solandingswouldbesimpleasit
turnsintoarealfloaterwhensloweddown.
AswiththeotherplanesIʹvedoneforKurt,thisoneisa
realniceflier.IdidnʹtattemptanyscaleaerobaticsbutIʹm
sureitwillbecapableofloops,veryʺbarrellyʺrollsand
nicestallturns.Againitsslowspeedcharacteristicsrelieve
thefearofcomingclosetotheground.Ialsothinkthatif
youwantedtotrysomethinglikeaMagneticMayhemor
EndoplasmagearedlikeintheE3D,itwouldworkwell
withthisplane.IʹveflownthesesystemsalsoandIthink
thisplanewouldbefinewiththem‐niceeconomical
alternative.“

CONTACTINFORMATION
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