Curtiss JN-4D User manual

CurtissJN‐4DʺJennyʺ41.25ʺ
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11



CurtissJN‐4DʺJennyʺ41.25ʺ

R/CScaleModelInstructions








CONTACTINFORMATION
Designedby:M.K.Bengtson
Prototypeby:BertAyers

ManufacturedandDistributedby:

BengtsonCompany
e‐mail:[email protected]
Web Site: www.aerodromerc.com

CurtissJN‐4DʺJennyʺ41.25ʺPage2
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11
CurtissJN4D“Jenny”
ThankyouforpurchasingtheCurtissJennymodelfor
electricflight.

THEMODEL
AsemiscaleadaptationoftheCurtissJenny,thismodelis
designedtobeeasytobuildandexcitingtofly.


FinishedModelByBertAyers

POWERSETUP
Themodelcanbesetuptobepoweredbythe6VS400
motorandtheMini‐Olympus2.33:1Gearboxwitha8x4
APCprop.Batterypowerpackcanbe8600mahNiCad
orequivalentNimhorLi‐poly.Thismodelisusing6
600mah.

R/CGEAR
Afourfunctionminireceiverandfourmicroservosareall
thatisrequired.Aileronservoscanbenothickerthan
9mmtofitintoaileronservobay.
SPECIFICATIONS
Morethan190lasercutparts
Scale: ~1/9
Channels: R/E/A/T
Wingspan: 41.25ʺ
WingArea: 330sqin
Weight: 26ozreadytofly(Modelshownabove)
PowerSystem:Speed400,Mini‐Olympusgeared,6V
Prop:  8x4APC
AirfoilType: Flatbottomed
Cowl:  N/A
Spinner: N/A
Wheels: balsa&plywood,Neoprenefoamtires
Covering:BalsaandLitespanorPolyspan
Decals:Availableonwebsite
PrototypeBy:BertAyers


BUILDINGTHEMODEL
Usetheplasticbagthatthekitcomesintocovertheplans
ineachofthebuildingsteps.Slitthebagdowntheside
andsealedendtoopenitupintoonelargesheet.Laser
cutpartscanbestbetakenoutofthebalsasheetsbyusing
a#11x‐actobladetocuttheminutebridgesinthelaser
cuts.
Pushingthemoutwithoutcuttingthebridgesmaybreak
thepart.Themodelabovewasbuiltwith1/8”square
stripscutfromtheexcessareasofthe1/8”lasersheets.
CAglueforthebalsapartsandepoxyforthelite‐plywood
partswereusedonthepicturedmodel.

TAILSURFACES
Thetailsurfacesareagoodplacetostart–toget
acquaintedwithbuildingwithlasercutparts.Findallthe
“S”partsonthe1/8”lasersheets,cutthesmallbridges
wherethelaserdidn’tcutandfinishcuttingthepart.The
partshouldpickoutofthesheetwithnoeffort.Allthe
“S”partsmakeuptheverticalstabilizerandrudderparts.
Some1/8”squarestockwillbeneededtomaketheribs.
Covertheplanswiththeshippingbagandpindownthe
parts.CAgluetogether.Allowtosetfor5minutesand
removefromtheplans.

TailSurfaceConstructionDetail
Youcansandandroundallsurfaces(exceptforS1)or
leavethesandinguntilyougeteverythingbuilt.
Findallthe“E”partsandrepeattheprocesstobuildthe
elevator.A1/8”doweloraluminumtubewillbeneeded
tojointheelevators.

CurtissJN‐4DʺJennyʺ41.25ʺPage3
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11

TailSurfaceConstructionDetail
Nowthatyouareanexpertatbuildingwithlasercut
parts,wecanproceedwithmorecomplicatedstructure.
WINGS
Thewingsrequirealittleprepworkbeforeassemblycan
begin.The1/8”x3/8”basssparsand1/8”squaresparsas
wellas1/4”squarebalsaLeadingEdgeand1/8”x1/2”
balsaTrailingEdgestockarenotsuppliedinthekit.One
topwingsparandonebottomwingsparcanbecutfrom
one36”piece.Cutallsparstocorrectlength.TheUTE
lasercutpiececanbegluedtothebottom1/8”squaretop
wingspar.CutouttheL1ribsandglueinthe1/8”
locatingdowels.CutouttheL4,R4andR7ribsandglue
onthesidepiecesthatreinforcethestrutjoints.Markand
cuttheribnotchesinthetrailingedges.

WingConstructionDetail
Nowwearereadytocutoutalltheremainingwingparts.
Startwithabottomwingtowarmupforthetasksofthe
topwings.Covertheplanswiththeshippingbagandpin
downthe1/8”x3/8”basssparand1/8”squarerearspar.
Startassemblingthepartswhereeveryoulike.Remember
toleanL1andR1ribs1degreeinwardusingtheRAG
lasercutpiece.

WingConstructionDetail
Thetopwingvariesinthatithasailerons.Theaileron
leadingedgeislasercutpartULE.Theaileronribsare
wedgeshapedandnotmarkedwithanumber.Theholes
intheribsaretoruntheaileronservowirestothecenter
section.

WingConstructionDetail
Thebottomwings(L1toL2)have1/16”sheetbalsaontop.
Tojointhetopwingstogether,acentersectionisbuild
witha1/16”plywoodbrace.Scrap1/8”x1/4ʺbalsais
usedontheinsidesofbothR8ribstoreinforcethecabane
strutjoint.Theplywoodbracehasdihedrlinit.Notethe
linewheretheaileronservoisthatindicateswhereand
howmuchtoblockupforthedihedralwhenepoxingthe
wingsandcentersectiontogether.

WingConstructionDetail
Theaileronservocanbenothickerthan9mmtofitinto
theribbay.Findthetwolasercut1/32”mountingparts
(withthewheelparts).Mounttheservoinyourfavorite

CurtissJN‐4DʺJennyʺ41.25ʺPage4
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11
manneronthesepanels,alwayscheckingthateverything
fitswithinthespace.Screwswerethisbuilder’s
preference—otherwaysareOK.

ServoConstructionDetail

ServoConstructionDetail
Sandthewingstotheprofilesshownontheplans(L.E.
andT.E.‐roundedtips)
Hingetheailerons,rudderandelevatorinyourfavorite
manner.

FUSELAGECONSTRUCTION
Thefuselageisbuiltastwostructures,afrontandarear
section,whichisjoinedovertheplan.Thissystemnot
onlykeepseachstagesimple,butitalsohelpstoensurea
straightfuselage.


FuselageConstructionDetail
Covertheplanswiththeshippingbag.Beginbybuilding
therearsection.Pindownthe1/8squarebalsastripsand
crossmembers.LetCAgluesetforafewminutes,
removepins,thenfoldplasticsheetovergluedpartsand
buildanothersectionrightontopofthefirstsection
makingbothsectionsidentical.

FuselageConstructionDetail
Jointhetwosectionsoverthetopviewplanwiththecross
members.Taperthetailpostontheinsideasmallamount.
CheckandrechecktomakesureeverythingisVERY
square.
Next,buildthefrontfuselageandaddthecabanestruts
whilethesidesareflushwiththeplan.Thismethod
insuresthatthestrutsareinproperalignment.


CurtissJN‐4DʺJennyʺ41.25ʺPage5
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11

FrontFuselageandCabaneConstructionDetail

FrontFuselageMotorMountConstructionDetail
JointhefrontsectionstogetherusingF1,2‐UC(goodtime
todrillholesforlacingundercarriagetofuse,whiletheir
flat),motormount(marktopofmotormounttomake
sureitisepoxiedinproperdirectionofmotorthrust)and
3F2spacers.Theseareallthesamewidth.Epoxy
together—checkanddoublecheck‐thateverythingis
SQUARE.Whenepoxyiscured,epoxyinF3andF8,these
arenotaswideastheforwardmembersandwillbe
taperedinaverysmallamount.


FrontFuselageMotorMountConstructionDetail
Thisisagoodtimetomountthemotorandmakesure
thereissideanddownthrustaspertheplans.F1will
needsomemanicuringontheinsidetogetS400/gearbox
tofit.
Timetojoinfronthalftobacksection.Thisbuilderhung
theplans(topview)overtheendofthetablesothatthe
frontsectionaftofthetherearcabanestrutsatflatonthe
plansandwasabletogluetherearsection(topdown)to
thefrontsection,keepingeverythingsquaretotheplans.
Asmallweightkeptfrontsectioninplace.Addformers
F2,F4,F5,F6andF7.
The1/16”balsatopdeckingneedstobepreformedby
soakinginhotwaterandtapedoverasimilarradiusas
formersF2.Allowtothoroughlydrybeforeremoving
frommold.Makeapatternoutofcardstockthatfits
perfectlyoverfuselage.Transferpatterntoformedbalsa
deck,trialfittofuselage.Donotcutoutcockpitholes
untildeckingisgluedtofuselage.Addthe1/16”stringers
torearfuselage.


PreFormTopDecking

FrontFuselageConstructionDetail

LANDINGGEAR
Bendthe1/16”musicwiretofitthepatternsontheplans.
Makeatemporaryfixturetosolderthewirestogether.
Drawlinesontheplanstodeterminewheretheaxlewire
needstolocateinrelationtotheplymountingplates.
Makesureeverythingissquareandcenteredbefore
soldering.Wrapthejointswithsmallcopperwire,then
solder.


CurtissJN‐4DʺJennyʺ41.25ʺPage6
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11

LandingGearConstructionDetail
Findthewheelparts.Useabrasstubetocenterthe1/32”
rimplatesonthe1/4”balsawheelcore.Addthe1/8”ply
collars.MassagetheNeoprenefoamrodintoacircle,then
CAgluetheendstogether.Taketimetogetitintoa
smoothjoint.

WheelKitConstructionDetail
Rolltheneoprenetireontothebalsacore.CAgluethe
neoprenetothe1/32“rimplate.UseCAsparingly,asit
reallylikestheneoprene.Transferthespokeconepattern
ontheplantoheavycardstock(make4).Useaballpoint
pentoscoreeachlineonthebacktomakeanimpression
of“spokes”.Foldthepaperalongthecreaselinesto
exaggeratetheraisedlines.Cutonespokelinetothe
centerandoverlaptothenextspokelinetomakeacone,
glue.Whiteglueisusedontheconeattachments.The
insideconemaybeattachedtothewheels.Theoutside
conesmaybeattachedatthis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scaleappearance.
Attach1/8”balsatothemusicwiretosimulatewooden
struts.Seetheplansforpropershape.


LandingGearDetail
INSTALLTHERADIOGEAR
Thisisagoodtimetoinstalltheradiogearwhilethe
fuselageisuncoveredandaccesstotheinterioriseasy.
DUMMYMOTOR
Assemblethedummymotorfromthebalsapartssupplied
andsandtoshape.
Notallpartsoftheenginearesuppliedassomearebest
fabricatedfromothermaterials.
INTERPLANESTRUTS
Findthe1/8”liteplywoodinterplanestrutsT1andT2.T1
goestothefrontwingpositionandT2isfortherearwing
position.Sandtoroundfrontandbackofstruts.Youcan
trialfitthewholeJennyskeletontoseehoweverything
fits.

ReadytoCover

ReadytoCover

CurtissJN‐4DʺJennyʺ41.25ʺPage7
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11
FINALASSEMBLY
Thismodelisdesignedtobeeasytoassemble.Assembly
startswiththemodelinverted.Blockupthecenter
sectionofthetopwing3/8”upsidedown.Thissupports
thedihedral.Holdingthefuselageupsidedownfitthe
cabanestrutsintothefourholesinthecentersectionof
topwing.Blockingupthetailposttheappropriate
amounthelpstoholdeverythinginplace.Makesurethe
fuselagesidesaresquaretothewingcentersection.
Measure(triangulate)fromthetailposttothewingtipon
bothsidestomakesurebothareequal.Whensatisfied,
putepoxyinthecabanestrutholes,re‐measureandlet
epoxycure.
Leaveeverythinginplace.Trialfittheinterplanestruts
andwinglocatingdowelsonthebottomwings.Dothe
tailpostmeasurementsonthebottomwingsalso.When
satisfied,epoxytogether.
Thebuilderofthismodeladdedanothersteptocheckfor
accuracy.Hemadethreefixturestoassurecorrect
incidenceonthewings.Thesefixturesweredrawnright
offtheplans.Twoweretapedtothefuselagetoassure
thetopwingincidenceandanotherusedtoassurecorrect
wingtowingdistancewhengluingtheinterplanestruts.


CheckingforAccuracy

CheckingforAccuracy
Turntheplaneoverandsetonthetableonitswheels.Use
thesameblockingforthetailposttoraisethetailsection.
Trialfitthehorizontalstabilizer/elevator(hingethe
elevatorsinyourfavouritemanner‐ifyouhaven’talready
doneso).Makesuretheleadingedgeofthestabilizeris
paralleltothewings.Measurefromthewingtipstothe
sameplaceonthestabilizertips.Triangulate.Shouldbe
equalonbothsides.Manicurethefuselagesaddle/tail
postifnecessarytoachieveaparallel.Addingmaterialis
betterthantakingawayinthisarea.Epoxywhensatisfied.

CheckingforAccuracy
Theverticalstabilizer/rudderisepoxiedontothetopof
thehorizontalstabilizerwithS1fittingintheslotinE9.
Useasquare‐‐‐theverticalstab/ruddermustbe90degrees
tohorizontalstabandwings.Checktomakesurethe
rudderdoesnotinterferewiththefullmovementofthe
elevatorjoiner,beforefinalgluing.Slipthecontrolhorns
ontothewirepushrodendsand,withboththeservosand
thecontrolsurfacescentred,gluethehornsintotheirslots.
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.
Afterthetopwingisattached,thelowerwingsareadded.
Applyepoxytothewingribthatmeetsthefuselage.
Attachthewingstothefuselage.Usethelocatingdowels
toassistwithaligningthewingpanels.Epoxyinthe
interplanestrutsatthistime.Allowepoxytoset.
Fittingtheguy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.Whilenottechnicallyrequiredthese
wirescanaddadegreeofstrengthtoyourmodel.

CurtissJN‐4DʺJennyʺ41.25ʺPage8
Copyright©2005‐11M.K.BengtsonAllRightsReservedRev07/11
Batteryhatch
Fashionabatteryhatchfrom1/32”ply.
Motorandgearboxtips.
Themini‐Olympusgearboxisverydurableandreliable
butitdoeshaveafewweakpoints.
1.Thereisoftenflashingonthegearsmakingrough
spotsorbindingwhichrobspower.Takeasharp
Exactoknifeandremovethisuntilyourgearboxturns
smoothly.
2.Excessflashingalsooccurswherethemotoris
mountedthatmakesalignmentpoorandagainrobs
power.TaketheExactoandcarveawaythisexcess
untilthemotorfitseasily.
3.Loosesetscrewsonthemainshaftandmotorlet
powerslipaway.Tightenallthesesetscrews
carefully.TOOMUCHwilldistortthepiniongear
andmakesanotherbinding.CAthepiniononthe
motorshaftifnecessary.Recheckthisafteranose
overwithpoweron.

Thismodelneedsan8‐inchpropforgroundclearance.To
getenoughpower,8cellsareamust.Usean8x4propfor
maximumstaticthrust,asthemodelhastoflyslowly.It
willnotbeafastmodel.NeitherwastheJennyafast
airplane.

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pavementorhardsurfaces.
Ongrass,themodelmayrequirehandlaunching.Be
carefulthatyourhandorfingersdonotcatchonthelower
rigging.Launchfirmlyandlevel.
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.

CONGRADULATIONS,YOUHAVEBUILT
ABEAUTIFULCURTISSJENNY!

CONTACTINFORMATION

Distributedby:
BengtsonCompany
e‐mail:[email protected]
WebSite:www.aerodromerc.com
