Bengtson Company Wedell Williams 52.4 User manual

WedellWilliams52.4”
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
WedellWilliamsRacer


R/CScaleModelInstructions






CONTACTINFORMATION
DesignedbyKurtBengtson
PrototypebyGregSmith

ManufacturedandDistributedby:
BengtsonCompany
POBox51102
PacificGroveCA93950
PhoneandFax:831‐393‐0991
e‐mail:[email protected]
WebSite:www.aerodromerc.com


WedellWilliams52.4”Page2
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
WEDELLWILLIAMS
ThankyouforpurchasingtheWedellWilliamsmodelfor
electricflight.

THEMODEL

Asemi1/6thscaleadaptationoftheWedellWilliams,this
modelisdesignedtobeeasytobuildandexcitingtofly.

FinishedModelbyGregSmith
POWERSETUP
TheAXI2820/12DirectDrivemotoranda12/8APCprop
powerthemodel.Batterypowerpackisa3100mah3s2p
lithiumpack.
SPECIFICATIONS
Morethan205lasercutparts
Scale:1/6
Channels:R/E/A/T
Wingspan:52.4
WingArea:441sqin
Weight:52oz
PowerSystem:AXI2820/12DirectDrive
Prop:12x8APC
Wheels:balsaplywoodwithNeoprenefoamtires
AirfoilType:flatbottomed
Cowl:builtupbalsaandplywood
Covering:BalsaandLitespan,PolyspanorCoverite
Microlite.

FEATURES
 Removablewingconstruction
 Wingalignmentisbuiltintomodel
 Scaledihedralwithailerons
 Scaleribplacementandairfoil
 Lightweightfrontbalsasheetedformer,stringerand
keelfuselageconstruction
 Lasercutpartsforbuiltupcowlincluded
 Lasercuttailpartsincluded
 Lasercutbalsaforbuiltupwheelpants

KitincludesVacuumFormedEngine–FrontOnly

KitIncludesVacuumFormedCanopy
ReplacementEngineFrontsandCanopies
Availableat:www.AerodromeRC.com
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
Thewingisbuiltinthreepieces,twoouterpanelsanda
centersection.Buildthesectionsandjointhemlater.
Startbybuildingthecentersection.Thesparsare1/4ʺ
balsa.Forthecentersection,everythingpinstotheboard.
Addtheplywoodlandinggearmounts.Inserttheblind
nutsandglueinplace.Addtheleadingedgestockafter
thebasicframeisdoneasthestockisinsertedinarotated
fashion.

WingCenterSection
Fortheouterpanels,thecentermostribisangledtoallow
fordihedral,andthekitincludesatemplatetosetthe
dihedralangle.
Oncetheleadingedgeison,shimuptheentirewing

WedellWilliams52.4”Page3
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
paneloffthebuildingboardwithscrap1/8ʺbalsaandre‐
pinthepanel(thatnowhasaleadingedge)totheboard.
Thisshimmingisnecessarysotheleadingedgeclearsthe
board,allowingthewholewingpaneltobepinneddown
again.

WingConstructionDetail
Addthetipribandthewingtipsupportpart.Notethat
theseareangledupwardslightly.Abalsaangletemplate
isincludedwiththekitsoyoucangettheangleright.The
bottomsparwillneedtobecrackedandbentupwardto
accommodatetheupwardangleofthetiprib.Thisisthe
onlypartofthewingassemblywhereyouneedtobea
littlecareful.Thewingtipsarebuiltwiththewingpinned
totheboard.Withthewingpanelpinnedtotheboard,
gluethecurvedwingtippiecetotheendrib,leadingedge
andtrailingedge,beingcarefultogiveitthecorrectangle
asshownonthebalsatemplateincludedwiththekit.
Crackthetopandbottomsparssotheycometogetherat
thewingtipandglueinthespars.Addtheplywood
riggingpointmounts.Theyaremadefromplywoodfor
thecasethatoptional1/16thmusicwireriggingisused.

WingPanelsJoined
Thethreewingpartsmustnowbejoined.Pinthecenter
sectioninplaceontheplan,lineupeverything,andshim
upthewingtipsasshownontheplantogettheproper
dihedral.Epoxytheribswheretheribsmeetandallowto
set.

Sheetthecentersectionforstrengthandtomakesurethe
epoxiedjointsholdfirm.The1/16balsaeasilybendsto
theslightcurveofthedihedral.Gregsheetedthetopand
bottomwith1/16balsa.Onthebottom,heonlysheeted
thejointswiththecentersection.

WingSheeting
TheLeadingEdgeoftheAileron
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.Alternately,tophingeusingcoveringashinging
material.InthismethodbeveltheLEoftheaileronfrom
toptobottom.
FUSELAGECONSTRUCTION
Thefuselageisofformerandkeelconstructionwithan
internalplyriserthatservestofixthecabaneattachment
points,undercarriageattachmentpoints,motormount,
lowerwingandbatteryintoaunifiedstructure.
Beginbyassemblingthetopandbottomkeelsontheplan.

FuselageLeftSideConstruction
BuildingoftheLeftSideoftheFuselage
Buildthe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

WedellWilliams52.4”Page4
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
formersareaddedmakingtheverticalalignmenteasy.
Adddiagonalbracesbeforeremovingtheassemblyfrom
theboard.

FuselageBracing
Finishingtheleftsideandstringers
Attachstringeralternatelyleftandrightinasymmetrical
fashiontoavoidabananafuselage.

FuselageRightSideFormersinPlace

FuselageSheetedandStringered

1/16thbalsasheetingisshown.Choosethelightestbalsa.

ThemotormountisdesignedforanAXI2820/12.Itiseasy
toassemble,withdownandrightthrustincorporatedinto
theparts.

FuselageMotorMount

TAILSURFACES
Layoutandgluepartsofthetailsurfacesontheplans.
Sandthetailparts,roundingoffalledges.Don’taddthe
hornsorhingethesurfacesuntilaftercoveringis
complete.

VerticalTailSurfaceConstruction

HorizontalTailSurfaceConstructionl
LANDINGGEAR
Thelandinggearismadefrom1/8”musicwire.

WedellWilliams52.4”Page5
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
AddingtheUndercarriagemounts
Theundercarriageismountedusing1/8”landinggear
straps.
WingFairings
Gregfashionedwoodenwingfairings.Hesays:”The
baseforthefilletsis1/32ply.Tomakeitbendaroundthe
forwardedgeofthewing,cutkerfs.Donʹtworryifyou
cutthroughthethinply,youcanjusttapethelittlekerf
piecesonthengluethemtotheframe.“

WingFairing1/32”PlyScoring

WingFairingAttachment

WingFairingSoftBalsaFill
“Ineededtoaddsomewoodtothefusetohave
somethingtogluethefilletbaseto.Theredarrowsshow
whereIaddedbalsawoodtothefuse.
Usewoodgluetogluethefilletbaseson.Itsetsupslowly
soyoucanadjustthingswhileitsets.Boltthewingonto
holdtheplyfilletbasesinplaceastheydry.
Withthefilletbaseson,cutchunksofbalsatodefinethe
outlineofthefillets.Puttywillbeusedlatertofillholes
soyoudonʹtneedtobetooneatasyoublockthebalsain.“

WingFairinginPlace
COWL
Thecowlismadefrom1/8”,1/32”plywoodand1/4”
balsa.Italsoservesasthebatterymountinglocation.His
planshowsaconventionalNIMHbatterypackagainstthe
firewall.GregfashionedabatterytrayforaLithium
batterythatfitsinthebottomofthecowlitself.Fourbolts
holdonthecowl.

CowlConstructionDetail
BatteryTray
Thebatterytrayinthecowlis1/16ʺply.Thebatterysitsin
bottomdeadcenterinthecowl.


WedellWilliams52.4”Page6
Copyright©2005KurtBengtsonAllRightsReservedRev10/05

BatterySitsinBottomDeadCenterintheCowl
COVERING
Anylightweightcoveringmaterialcanbeused.Polyspan
withdopeorMinwaxPolycrylicmakesagoodchoice.
Litespanisalsopopular.Gregusedwhiteandblack
CoveriteMicrolite.
DecalsforthismodelareavailablefromCallieGraphics
http://www.hobbies‐n‐stuff.com/
WHEELS
Gluingthe1/16”plysidesonthelaminated1/8”plywood
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.
WHEELPANTS

WheelPantsConstructionDetail
Brassstripsaresolderedtothegeartoattachthepantsto
thewiregear,Thepantsarethenboltedtothebrassstrips.
Theplywoodpartsaregluedintothepants.Thehardest
partonthegearisholdingeverythinginplacewhileyou
solderthebrassstripstothegear.Gregusedmedical
hemostatstoholdthestripswhilesoldering.

LandingGearConstructionDetail

LandingGearConstructionDetail

INSTALLINGTHERADIOCONTROLGEAR
ServoBay
Getthebulkof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.Usea“Y”wiring
harnessconnectortowiretheservostoasingleradio
connection.Ifdifferentialaileronthrowsaredesired,
rotateeachservohornforwardabout20degrees,while
maintainingtheneutralpositionoftheaileron.This

WedellWilliams52.4”Page7
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
shouldcounteradverseaileronyaw.
ASSEMBLY
Wing
Thewingmaybemaderemovableornotdependingon
thebuildersneeds.Gregmadehisremovable.

WingAttachmentPoints

FuselageWingAttachmentPoints
FittingTailSurfaces
Thehorizontalstabilizerslidesintoslotsinthesideofthe
fuselageformedbyF8andF9.Insertthestabilizeranddry
fittheelevatorusingCAhinges.Theverticalstabilizer
alsofitsintoaslotinthetopofthefuselageformednear
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.
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.
Gregmadehisriggingremovable:”Theflyingwiresare
thickelasticthreadfromacraftstore.Isinkonemagnetin
themodel,withitstopevenwiththemodelskin,andhold
itwithadropofCA.Ithentakeanothermagnet,andCA
theendofthethreadtoit.Ipaintthetopmagnetsothatit
blendswiththefuse.Thismakestheattachmentpoint
almostdisappear,anopticalillusion.Ipaintthethread
afteritisonthemodelwithsilveracrylicpaint.”
BalancingtheModel
Balancethemodelatthepointshown.

FLYING
ThemodelshouldROGongrass,pavementorhard
surfaces.Itmayrequirecoordinatedturnsusingboth
aileronsandruddercontrol.Thisisduetoadverseyaw.
Halvingtheailerondownthrowmayreducetheeffect.
Thiscanbeaccomplishedbyrotatingthecontrolarmof
theaileronservoforwardabout20degrees.

InforaLanding
Thetailsurfacesshouldnotneedexcessivethrows.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.


WedellWilliams52.4”Page8
Copyright©2005KurtBengtsonAllRightsReservedRev10/05
HerearesomeexcerptsofGregʹsmaidenflights.

“Firstattemptwithan11x7MasterAirscrewwoodelectric
propanda3100mah3s2plithiumpackshowednot
enoughpower,soIchangedtoa12x8APC.AUWwas
about52oz.Thiscombinationprovidedmassivepower,
modelisairborneinabout30feet.Thebigcowlcreates
significantwindshadow,soafairamountofrightrudder
wasrequiredtokeepittrackingstraightontake‐offroll.

Withthedragofthebigcowl,coupledwiththelight
designandgoodwingarea,themodelflieswelland
briskly,althoughnotreallyfast.Iwouldnʹtcallitaʺslow
flyerʺbutitʹsnotquiteafastsportplane,althoughits
speedisdefinitelyfasterthanscalewhenyoupushit.Full
powerproducesarapidclimbvs.morespeed.Inthe
futureIwillconsidermixinginsomedownelevatorwith
throttleonmycomputerradio.Itslowswaydownfor
landing,orcruisingifyouprefer.Mostoftheflightwasat
½throttle.Thelandingrolloutwasabout20feetina
lightbreezelandingintothewind.

Loopsareeasyandtight,rollsprettyandareatamodest
rate.Theoriginalwasnotintendedtoroll,sothescale‐size
aileronslimitthemodel’srollratecomparedtomostsport
modelsthatcanrolllikecrazy.

Adverseyaw,typicalonmodelslikethis,wasnoticeable
althoughnotaproblem.Builderswithcomputerradios
maywanttoconsidermixingruddertoaileronsand
incorporatingdifferentialbyoperatingtheaileronsofftwo
channels.

Throwsof+/‐1ʺR,1‐1/8ʺE,1‐3/16ʺseemedtoworkwell.
Aslongasyouarereadyforitandstandonrudder,you
cantaketrackstraightontake‐off.

Allinall,amodelwithverygoodflightcharacteristics
andauniqueprofileandahappybuilder.“


CONTACTINFORMATION
Distributedby:
BengtsonCompany
POBox51102
PacificGroveCA93950
PhoneandFax:831‐393‐0991
e‐mail:[email protected]
WebSite:www.aerodromerc.com
