Hobbico Sturdy Birdy II User manual

INSTRUCTIONMANUAL
WARNING! THIS IS NOT A TOY!
Assemblyandoperationofthisaircraftmustbedonebyorunder
the direct supervision ofa responsible adult. If not handled
correctly, this model iscapableofinflicting seriousbodilyharm.
It isyourresponsibilityandyoursaloneto assemblethis model
correctly, properlyinstallallR/Ccomponents andto testand
operateit in a safeandresponsiblemanner.
EntireContents© Copyright1998 HCAA1010 V20
ARF1P01

Stock # Description Qty
Loosein Box
Al UM007PAluminumChannel1
ARF1F01 PlasticFuselage Tube 1
ARF1P01 InstructionBook 1
ARF1R05 1/64 Plywood Fin
Doubler1
ARF1W02 PlasticWing Protector 1
EM20481 EngineMountLeft 1
EM2048R EngineMountRight 1
FWING02LMolded Foam WingLeft 1
FW1NG02R Molded Foam Wing Right 1
L-6ULandingGear 1
NYLON87 CA HingeStrip 1
PLTB009 24" WhiteInner Pushrod 2
PLTB01124" Grey OuterPushrod 2
PLTB012 11-3/4" InnerPushrod1
PLTB013 11-3/4" Outer Pushrod 1
WIRES 16Threaded Link Rod 5
ARF1A01 Subpack
Stabilizer& WingParts
ARF1R04 1/4 x 1/2 x 13
Balsa Fin Doubler 1
ARF1S011/4Balsa
Stabili/er Front 1
ARF1S02 1/4 Balsa Stabili/er 1
ARF1S031/4 Balsa Elevator 1
ARF1W01 1/8 Plywood
WingJoiner1
ARF1A02 Subpack
Fin& RudderParts
ARF1R01 1/4 Balsa Fin Front 1
PARTS LIST
Stock# Description Qty
ARF1R02 1/4Balsa Fin 1
ARF1R03 1/4Balsa Rudder1
ARF1A03 Subpack
SmallWood Parts
ARF1F03 9mm Plywood
Firewall Doubler1
ARF1F04 1/4 Plywood Firewall 1
ARF1F05 1/4Ply
LandingGear Supports 2
ARF1F06 Pushrod Holder
(3/4 x 1 /2 x 1 ) 1
ARF1S04 1/16Plywood
Stabili/erDoubler1
DOWEL030 1/4x31/2 Dowel 4
ARF2A04 Subpack
LongAileron Parts
ARF2W03 3/8 Tapered TE 2
ARF2W04 3/8 Tapered Aileron 2
ARF2A05Subpack
SmallAileron Parts
ARF2W05 Grooved CenterTE 2
ARF2W06 TE Support 2
ARF2W08 Servo Rails 2
NYLON20 Nonthreaded Swivel2
NYLON21 Swivel Clevis 2
WBNT110LAileron TorqueRod Left 1
WBNT110R Aileron Torque Rod Right 1
Stock# DescriptionQty
ARF1MOI Subpack Hardware
(ContainstheFollowing)
NUTS0014 40 BlindNut6
NUTS002 4 40 Hex Nut2
NUTS010 6 32Hex Nut4
NUTS014 8 32Hex Nut2
NYLON03 NylonControlHorn 2
NYLON 17 Nylon Clevis 3
NYLON52 5 1/2NylonTie 2
SCRW002 2 56x 5/8 Bolt 4
SCRW010 #4x5/8
Sheet Metal Screw4
SCRW024 #2 x 3/8
Sheet MetalScrew 8
SCRW052 4 40 x 5/8 Bolt 4
SCRW053 8 32x I /2Bolt 2
SCRW055 6 32x 1 1/2
SHCap Screw 2
SCRW104 4 40 x 1 1/4
MachineScrew 4
WBNT146 Prebent Tailskid 1
WIRES20 1 Threaded LinkRod 3
WSHR002 #4 Lock Washer 2
WSHR004 #6 Flat Washer 4
WSHR005 #4FlatWasher 4
WSHR010 #8 Lock Washer 2
WSHR011#8 FlatWasher 1
2

TABLEOFCONTENTS
Parts List.................................................2
Introduction............................................3
Additional Item Description .....................3
Additional Item Check List.......................4
ToolsorSuppliesNeeded.........................5
Fin & Rudder Construction......................5
Installing CA Hinges ................................6
Stabilizer&ElevatorConstruction...........8
Wing Assembly ......................................10
Covering................................................14
Installing the Hinges..............................14
Attaching the Control Horns..................15
Fuselage Construction...........................15
Final Assembly ......................................22
Balancing..............................................23
Getting Ready for Flying ........................23
Flying....................................................23
Repairing .................................Back Cover
INTRODUCTION
Congratulationson yourpurchaseof the
HOBBICOSTURDY BIRDY II.THE FIRST
REAL SUPER TRAINER. You now own the
BEST FLYING durabletraineravailable. By
following these instructions asyou assemble
the model, you will have a great flying plane.
It will not only teach you how to fly, butwill
stick by you while you learn, no matter how
long that may take!
The firstthing you should do after reading
this paragraph ischeck the parts in this kit
against the parts list to make sure everything
ishere.
We stronglyrecommendthatyou jointhe
Academy ofModel Aeronautics. Beingan AMA
member entitles you to liability insurance and
putsyouintouchwithyourlocalflying
club. It alsoincludes a subscription to MODEL
AVIATION magazine,whichhas a monthly
listingofthelatestnewsinmodelaviation.
Insurance isthe most important advantage of
theAMA membership.Ifyourmodelhits
someone or something, you areliable for any
damage itcauses.
You can contactthenationalAcademyof
ModelAeronautics,whichhasmorethan
2,500 charteredclubs across the country.
Through any one of them, instructor training
programs and insured newcomer training are
available.
Contact the AMA at the address ortoll-free
phonenumberbelow.
Academy ofModel Aeronautics
5151East Memorial Drive
Muncie, IN47302-9252
Tele. [phone]
Fax[phone]
WebSite:
HTTP: //WWW. MODELAIRCRAFT. ORG
We alsorecommend that you join your local
flyingclub. There you will findpeople who
can help you learn to fly and teach you the
safewaysofhandlingyouraircraft.
ADDITIONALITEMS
DESCRIPTION
Here isa description ofsome ofthe items you
willneedtoassembleyour STURDYBIRDYII
GLUES
CA (Cyanoacrylate) glues will be used to glue
thewood partstogetherbecausetheyare
strong and very fast curing. Do not use CA
glues for the wing construction because most
CA glues will attack and dissolve thefoam
wing. They come in differentviscosities. Thin
CA glue can be used when gluing parts with
agood,tightjoint.WhenusingthinCA,
3

assemble the parts first and then add the
glue. It will penetrate the jointand cure in a
coupleof seconds. Thick and mediumCAs
areappliedto thepartsbefore theyare
assembled since thegluewillnotcurefor
20-30 seconds. This longer curing time gives
youmoretimeto get thepartsassembled
accurately before the glue cures. The thicker
consistency also helps fill poor fitting joints.
CA acceleratorspraycanbe veryhandy
forspeedingupthecuringprocess of the
thick CAs.
Epoxy isa two-part adhesive that has tobe
mixed before it will cure.We will use epoxy
glueforthe wing assembly since it takes a
little longer to cure and does not attack the
foam. Epoxies come in several differenttypes
with many differentcuringtimes. You should
buysome epoxy witha 30-minutecuring
time foruse here.
ENGINE
The STURDYBIRDY II isdesigned to flywith
astandard .20 size 2-stroke engine. The OS
.20 FP is a great,inexpensiveenginethat
provides plenty of power. This combination is
ideal for the average beginner. A .25 - .30size
engine can be used if you would like snappier
performance,especially at higher elevations
where the air is thinner.We recommend that
you donotuse an engine larger than a .30
as theadditionalweightmakes theplane
more difficultto fly at low speeds. The engine
mount provided with the STURDYBIRDY II
willfitmost .20- .30engines.
RADIO
The STURDYBIRDY IIrequires 4 channels to
fly.The radiosystem you purchaseshould
have standard sizeservossothey will fitinto
the fuselage channel. Mini or micro servos will
alsoworkbuttheywillrequiresome
modifications to fitproperly. Largeservoswill
notworkintheSTURDYBIRDYII.
FUELTANK
The STURDYBIRDY IIIwas designed to hold
a6 oz. square tank.A 4 oz. tankwill also
work but willgiveyou shorter flight times.
COVERING
Although not absolutely necessary, the "tail
feathers"andthewingshouldbothbe
coveredwitha "lowheat"typeironon
covering. EconoKote^ and Black Baron® Film
arebothgoodcoveringstouseonyour
STURDY BIRDY II.The coveringwillnot
only make yourplane look nicer, butit will
alsoadd strength and make itlastlonger.
CHECK LIST OF ADDITIONAL
ITEMSYOUWILLNEED
D.20 -.302-Stroke Engine
D4 Channel Radio
D4 Standard SizeServos
DSeveral 9 X 4 or 9 X 6 Propellers
D2-1/2"Wheels (2)
D6 oz. Square Fuel Tank
DBox #64 Rubber Bands
DThin CA (Cyanoacrylate) Glue loz.
DThick CA (Cyanoacrylate) Glue loz.
D30-Minute Epoxy 4oz.
DRoll of Low Heat Iron-On Covering
DFoam Rubber for Cushioning Receiver
D12"Standard SizeFuel Tubing
D3/4" Wide Nylon Reinforced Tape
QuestionsorProblems?
Contact us at:
Hobby Services
Attn: Service Department
1610Interstate Drive
Champaign, IL61821-1067
[phone]
4

TOOLS& SUPPLIESNEEDED
DSealing Iron D Razor Saw
DHobby Knife D Pliers
DScrewdrivers D T-Pins
DHammer D Wax paper
DSanding Block or Bar Sander
DNylon Reinforced Strapping Tape
DHand or Electric Drill
DDrillBits(3/32",1/8".3/16",5/32",7/32")
FIN& RUDDER
CONSTRUCTION
glue has cured, flip the piecesoverand adda
littleglue to the other side.
D3.Asshown in the above sketch, cut 18
hinges fromthesupplied2" x 9"composite
hinge material. You will need five hinges for
the elevator and threefor the rudder. Each
aileron getsthree hinges.
D1.The finismade upof the three pieces
shown above. Locate these three pieces and
lay them out.
D4. Lay therudderinplaceagainstthe
trailingedge of thefin.Using a hinge as a
template, mark the hinge locations. They are
spacedoutso thattheouterhingesare
approximately 1"from the ends of the rudder
and the middle hinge isinthe center.
D2. Glue the front part ofthe fin to the main
part usingthinCA. Assemble the two parts
and check to make sure they fitproperly. Then
applya lineofCA alongthe joint. When the
D5.Drawa linedownthemiddleof the
trailingedge of thefinand also down the
middleof theleadingedge of therudder.A
sheet of wood (or anything)1/8" thicklaid
down next to thepiece makes it easy to do
this. Transfer the hinge locating marks from
the sideto the edgesasshown above
5

Note: Before proceeding to hinge the rudder.
readcompletelythroughthesectionon
Installing CA Hinges. Do not useany glue
untilafter the tailsurfaces arecovered.
few timesto providemoreclearance(itis
really theback edge of theblade that does
the work here in widening the slot).
INSTALLINGCAHINGES
Thehingematerialsuppliedinthiskit
consists ofa 3-layer lamination ofmylar and
polyester. It isspecially made forthe purpose
of hingingmodelairplanecontrolsurfaces.
Properly installed, this type of hinge provides
thebest combinationof strength,durability
and easeof installation. We trust even our best
showmodelstothesehinges,butitis
essential to install them correctly. Please
readthefollowinginstructionsandfollow
themcarefullytoobtainthebestresults.
These instructions may be used to effectively
install anyofthe various brands ofCA hinges.
The most common mistake made by modelers
wheninstallingthistypeof hingeis not
applying a sufficientamountof glue to fully
secure the hinge over its entire surface area;
or, the hinge slots are very tight,restricting
the flow of CA to the back ofthe hinges. This
resultsin hinges thatare only "tack glued"
approximately1/8" to 1/4"intothehinge
slots.Thefollowingtechniquehasbeen
developedtohelpensurethoroughand
secure gluing.
A.Cutthehinge slot usinga # 11blade in a
standard#1knifehandle.The slots should
be about 3/4" deep. The CA hinges provided
have a thicknessthatfitsthistypeof slot
very well. Cutoff the corners of the hinge at a
45 degree angle and trial fitthe hinge into the
slot. Ifthe hinge does not slide in easily, work
the knife blade back and forth inthe slota
CAUTION:Do notdrillthisholewhen
hinging a foam wing, as thishole would allow
too muchCA to penetrate and cause damage
to thefoam.
B. Drill a 3/32" hole, 1/2" deep. in the
centerofthe hingeslot.Ifyou use a Dremel
MultiProforthistask,itwillresultin a
cleaner hole thanif you use a slower speed
power or hand drill. Drilling the hole will twist
some ofthe wood fibers into the slot, making it
difficultto insertthehinge,soyou should
reinsert the knife blade, working it back and
forth a few times to cleanout the slot.
C. Insert thehinges and install the control
surface. Verify the left-right positioning of the
control surface and closeupthe hinge gap to
1/32" or less.Itisbest to leave a very slight
hinge gap, rather than closing it uptight, to
helpprevent theCA from wicking along the
hinge line. Ifyou have cut your hinge slots too
deep, the hinges may slide in too far. leaving
only a small portion ofthe hinge in the control
surface. Toavoidthis,you may inserta small
6

pinthrough the centerofeachhinge,before
installing.Thispinwillkeepthehinge
centered while installing the control surface.
Note: When hinging the ailerons, which use
torquerods, use a toothpickto force epoxy
down thehole drilledfor the torquerod. In
the case ofthe rudder, be sure not to let glue
get into the bearing tube.
D6.Trial fitthe finand rudder together using
thehingesto checkforproperalignment.
DoNotglue the hinges in place yet!Sandthe
rudder and/or fin sothey match eachother at
the top.
above.Use a razorsawto cut the excessoff at
the leading and trailing edges.
D9. Check thefitof thefinassembly into
the aluminumchannel. Itwill most likely be
alittle loose and we want a nice, tight fit.Add
astrip of the 1/64" plywood doubler to ONE
side of the fin.Glue it to thebalsa doubler.
Check thefitagain and if itis still a little
loose, add a plywood doublerto theother
side. Ifnecessary, you can sand the plywood
slightlyto helptheassembly fit.Also, you
canhavethecoveringmaterialcontinue
downoverthedoublersifyouneedthe
additional thickness.
D7.Remove the hinges from the
rudderand bevel theleading edge
with your sanding block asshown in
thesketch.Thisistoallowthe
EDGE VIEW
rudder to swing either direction once
the hingesareglued inplace.
D8.Add the1/4" x 1/2" balsa doublerto
each side of thefinas shown in thephoto
D10.Position the finassembly in the channel
with the trailing edge of the fineven with the
end of the channel. Pressit in place. Mark the
locationof thestabilizerboltholeson the
bottom ofthe fin and then remove the fin from
the channel.
7

D11.Wrap a piece of masking tape around a
7/32" drill bit about1/2" from the end of
the bit.
STABILIZER &ELEVATOR
CONSTRUCTION
D12.Drill two holes in the bottom ofthe fin
assembly to make a space for thestabilizer
bolts. Becareful not to drill any deeper than
the masking tape or you may drillthrough the
side ofthe fin.
D13.Use a sanding block to round the edges
ofthe fin/rudderassembly as shown above.
Give the sides a quick sanding with some fine
sandpaper to get them ready for the covering.
This completes the basic assembly ofthe fin
and rudder. The hinges and control horn will
be installedafter everything iscovered.
D14.Thestabilizerandelevatorare
assembledfromthesethreemainpieces.
Locate these and let's get started.
D15.Glue the frontofthe stabilizer to the
back using thin CAjust asyou did for the fin
in step #2.
D16.Markthehingelocationsusingthe
same technique you used in step #4. There are
five hinges used here. The outerhinges are
8

approximately 1"from the edge. The middle
hinge isin the center and the other two hinges
arecentered between the outer hinges and the
middle hinge. These hinge locations are not
critical, but proper placement makes it easier
to findthe slots afterthe parts are covered.
Cuttheslots for thehinges and test fitthe
stabilizer and the elevator together to check for
proper alignment between the two parts.
D17. Use some thick CA to glue the 1/16"
plywood doubler in place on the stabilizer.This
sideisnowthebottomofthestabilizer.Use
aruler to get this piece centered as close as
possible.Use a drafting triangle or carpenter's
squareto drawa lineperpendicularto the
stabilizertrailingedgeand through the center of
the stabilizer to the point where the leading
edgesmeet.
D18.Usea penciland a rubber band to hold
thestabilizerinplaceasshowninthe photo.
Sightdown the bottom ofthe channeland line
the stabilizer upwith the channel (using the
line you just drew). When you aresatisfied with
the alignment, draw a linedown both sidesof
the channel on the top ofthe stabilizer.
D19.Remove the pencil and rubber band.
With the stabilizer centered over the lines, drill
two 1/8"holes through the stabilizerusing the
holes in the channel asa guide. The trailing
edge ofthe stabilizer should be slightly past
the end ofthe channel.
D20. Use a sanding block with some fine
sandpaperto roundofftheleadingedges,
trailing edge and the tips asyou did forthe
finand rudder. Also sand the top and bottom
surfacessmooth. This completesthebasic
assembly of the stabilizer and elevator. The
control hornand the hinges willbe installed
after the tailiscovered.
9

WING ASSEMBLY
INSTALLTHE AILERONS
Use the sketch to help you determine which
side isthe top and mark the top side of each
piece. Makeanothermark7/16"fromthe
"inboard" end of each piece. Notch eachpiece
to make a slot for thetorque rod.
Note:The threaded portion ofeach torque rod
should stick outthetop of each wing. Also
there will be a "right" and a "left" center trailing
edgepiecesodon't make two exactlyalike.
BalsaSUBTE26-1/2" Long
D1.Locate thetwo balsa 15/32" x 3/8 x
26-1/2"Sub TrailingEdge pieces (Sub TE).
Trialfitthe Sub TEagainst the trailing edge of
each wing half. The Sub TEshould be oriented
as shown in thesketch withthe90-degree
corners along the bottom of the wing. Epoxy
the Sub TEto the trailing edge ofeach wing
half. Pins or tape canbe used to help hold the
Sub TEin place while the glue cures.
BalsaCENTERTE3-7/8 " Long
D2. Locate thetwo balsa 3/8" x 1-1/4" x
3-7/8" tapered center trailing edge pieces.
D3.Use 150-220 grit sandpaper to roughen
theoutersurface ofthe torquerod bearing.
Slide the bearing toward the threaded end of
thetorquerod and puta small amountof
petroleumjellyaroundtheendsofthe
bearing tubeto prevent epoxy from seeping
in. Spread some epoxy in the slot and on the
leadingedgeof thecentertrailingedge
pieces. Do not apply any epoxy within 1/4" of
thenotchor you may glue thetorquerod.
Insert the torque rods into the slots with the
threadedportionssticking outthroughthe
notches.Positionthecentertrailingedges
against the wing sub trailing edge. Align the
center trailing edges and pin or tape them in
placewhile the glue cures.
10

D4. Epoxythetwo 11/32"x 2" x 1-5/8"
Tapered TESupports to the inboardbottom of
eachcentertrailingedgeasshowninthe photo.
D6.Hold the 3/8"x 1-1/4" x 22-1/4" Ailerons
in place againstthe sub trailing edgeand under
the torque rods. Mark the location where the
torque rods willenter the ailerons.Drill a 3/32"
holeineachaileronto accept the torque rods.
D5.Usea sandingblockwith 150-grit
sandpaper to sand the innerends of the sub
trailingedge. centertrailingedge and the
tapered trailingedge to match theangle of
the foam wing end. Becarefulnot tochange
the angleofthe foam wing.
AILERON
22-1/2" Long
ARF2W04
D7.Cuta groove in the leading edge of the
aileron to allow clearance for the torque rods.
Trialfittheaileronsin placeandcutas
necessary until they fit.
D8.Draw an accurate centerline along the
leadingedge of the aileronandcutthree
hinge slots in each aileron. The hinge slots
should be approximately 1-1/2",10"and 18"
from the wing tip. Placethe ailerons against
thesubtrailingedge andmarkthehinge
locationson thewing.Drawa centerline
down the sub trailing edge and cut the hinge
slotstomatch the ailerons.
D9.Using a sanding block, sand the leading
edge ofeach aileron to a "V"shape.
11

D10.Insertthehinges intotheslots and
trial fitthe ailerons in place on thewing. Do
notgluethehingesuntilafteryouhave
covered the wing. Sand the outboard edge of
thesubtrailingedges and theaileronsto
match the foam wing tips.
JOIN THE WING PANELS
D1.Use a sanding block with some fine grit
sandpaper (240 - 320grit) to remove the little
nubsandanymoldlines lefton the wing
from the molding process.
D2. Testfitthe 1/8"plywood dihedraljoiner
in the slots in the wing to make sure it fits
nicely. Mix upabout1/2 oz. of epoxy and
spread itthroughouttheslot in one wing
panel.Withthewingpanelupsidedown,
insert the joinerin place and squeeze outall
the excess epoxy sothatthejoinerisflush
with the bottom of the wing (which is facing
up).Try to use enough epoxy sothatthe slot
iscompletely fulland levelwith the surface of
the wing.
D3.Laysome wax paper down on the work
surfaceandmixuponeounceof epoxy.
Spread the epoxy throughout the slotand on
the root (middle end) ofthe other wing panel.
Slide thetwo wing panels together and line
them upas close as possible.Use several
T-pins and masking tape to help hold them in
alignment. Flip the wing assembly over sothat
the bottomof thewings are facingupand
make sure that the joiner isseated properly in
the slot. Wipe off any excess epoxy before it
starts to cure. It isimportant that the wings
are joined with both panels being accurately
aligned with eachother.
D4. Allow the epoxy from the last step to
fully cure.
Note: The tape used in this step is3/4" wide
nylonfilamentreinforcingtape.Thisis
self-adhesivetapewithnylonfilaments
runningthelengthof thetape.Itis also
referred to as"nylon filamentstrapping tape,"
or "nylon reinforced packaging tape." You can
obtain it at any store thatsells stationery and
packagingmaterialsor at mosthardware
stores.Be suretouse3/4"widetape.
Narrower tape will not provide the wing with
12

proper reinforcement. Make sure the tape is
applied with no wrinkles and that the strips
arestraightandparallelfromwingtipto
wingtip.Ifthistapeisnotapplied,if itis
appliedincorrectlyor ifa differenttype of
tape is applied,we cannot be responsible
for anywingfailurethat may occur.
D5.Placethe wing upside down on the edge
of a table sothatonly 1/2 of thewing (from
one wing tipto the center joint)isresting on
thetable.Startingatthewingtipthatis
restingon thetable,lay a stripof nylon-
reinforcedstrappingtapedownso thatit
crossesover the center jointdirectly over the
wing joiner.
Pressthe tape firmlyonto the wing and down
into the fillet(where thebottom of the wing
meets themountingplatform)and then flip
thewing aroundand continuethestripof
tapeoutto theotherwingtip.Applytwo
more strips of tape between this strip and the
trailingedge of thewing.The fourthstrip
should be added between the firststrip and
theleading edge of thewing. The previous
photoshowswherethestripsshouldbe
located.Trytogetthistapestuckdown
as tightlyas possiblebecauseitaddsa
tremendousamountof strength to thewing
when properly applied. Make sure you do not
changethewashout(twist)ordihedral
(V-shape) of thewing when applying thetape
strips.Ifyouareplanningon doingsome
aerobaticsor combatwithyourSTURDY
BIRDY II, you should also put three strips of
tape on the top surface of the wing.
INSTALLTHE WING PROTECTOR
D1.Use a sharp hobby knifeor a Dremel®
Tool with a tapered cutting bit to trim out the
servo and torquerod cut-outs in the Plastic
Wing Protector. There are scribe lines on the
bottom surfaceof the protector to help guide
you. Trial fittheaileron servo in place and
trim asnecessary to make it fitproperly. Use
scissorsoryourhobbyknifetotrimthe
outside edges of the wing protector along the
remaining scribe lines.
D2. Placethe wing protector on the center of
the wing sothe torque rods fitthrough their
holes.Draw a line on thewing aroundthe
servo cutout. Remove the protector and carve
out a hole in the foam wing to fityour servo.
Carve out an extra 1/4" square groove in front
and behindtheservo cut-outfortheservo
rails. Drill a 1/2" diameter hole for the servo
wires down through the front edgeof the servo
cutout.Becareful not to cut the plywood wing
joiner when performing these operations.
D3.Glue the 3/16"x l/4"x 1-1/4" Basswood
Servo Rails in place along the frontand back
edges of theservo cut-out.Puttheaileron
servoinplaceandmarkon theplastic
protectorwhere theservo mountingscrews
should be. Drill 1/1 6"diameter holes on the
marks you justmade and mounttheservo
using the screws provided with your radio.
D4. Trial fitthe wing protector assembly on
the wing and enlarge the cutouts in the foam
13

wing if necessary to make the protector lie
flatagainstthewing.Whensatisfiedwith
thefit,removetheservo.Usecoarse
sandpaper to roughen the bottom of the wing
protectorsothegluewillholdbetter.Use
epoxy to glue the protector in place.
D5.Trial fitthe ailerons for this step. Mount
the aileron servo with the screws provided in
the radio system and assemble the pushrods
as shown in thesketchabove. Attachthe
pushrods to the torque rods by screwing the
Aileron Clevis Connectorontothethreaded
portion of the torque rod. Use a pair of needle
nose pliers to make the Z-bends and attach
them to the servo horn. Turn on your radio.
plugin youraileronservo andadjustthe
centeringoftheservohornuntilitis
centeredandtherightaileronmovesup
when you move the transmitterstick to the
right.Adjustthenylonclevisuntileach
aileronis in a neutralpositionwhenthe
transmittersticks and trimsare centered.
Also adjusttheposition of thenylon clevis
connector on the torque rod to achieve 7/16"
of upand down movement.
COVERING
D1.The tailsurfaces (fin, rudder, stabilizer
and elevator) should be covered with one of
theiron-oncoverings to helpprotectthem
from becoming fuel soakedand ruined. If you
are alsogoing to coverthe wing, which will
helpitlooknicerlonger(andadda
small amountof strength),you can save a
littlemoney by buyingonly onerollof low
temperaturecovering(EconoKote,Black
Baron Film, etc.) and usingitfor boththe
wing and the tail surfaces. Otherwise you can
use any type of covering for the tail surfaces,
but remember to use a low heat covering for
the wing. A few stripes or yourAMA number
canreally add to the looks ofyour STURDY
BIRDY II.
D2.Followthe instructions that come with
the covering and cover the tail surfaces at
this time. It isa goodidea to cover the bottom
surfaces first to get familiar with the covering
since thesesurfaceswill normallynot be
seen. Whencoveringthewing,cover right
over the tape and plastic wing protector. Try
to use aslittle heat aspossible.
ATTACHINGTHECONTROLHORNS
D1.Position the nylon control horn on the
left side of the rudderabout 1"upfrom the
bottom with the fourholes lined upwith the
leading edge. Use a dropof ThinCA to tack
glue the horn in place.
14

D2. Drilltwo3/32"holesthroughthe
rudderusing the control horn asa guide.
D2. The controlsurfaceswill takesome
abuse in the learning-to-flyprocess, soyou
must securely glue thehinges in place. Use
fourto sixdropsof CA on each side of the
hinge to secure them. Try to get the surfaces
asclose together as possible, butwork the
controlsurfacesback andforthwhilethe
glue is curing to make sure they work freely
without binding. Also, be careful not to glue
the two surfaces together.
D3. Secure thehorn to the rudder with two
2-56 x 5/8"machinescrews.The screws
should thread into the nylon "nut plate" on
the opposite side of the rudder. Although not
necessary, you may use some wire cutters or
an abrasive cutoff wheel to cut the screwsoff
evenwith the plate.
D4.Theothercontrolhornshouldbe
installed on thetopsurfaceof theelevator
about 1"to the right ofthe centerline. Follow
thesameprocedureforinstallingthis
control horn.
INSTALLINGTHE HINGES
D1.After coveringthe tail surfaces and the
wing, thehinges can be installed. Use your
hobby knifeto findtheslots you cutearlier
andmakeslitsin thecovering soyoucan
push thehinges intoplace and trialfitthe
pieces together again. (Refer to the CA hinge
sectionon page 6.)
FUSELAGECONSTRUCTION
D1.Locate the 3/8" plywood
firewalldoublerandround
offthecornerswitha
sandingblock.Test fitthe
doubler into the frontof the
plasticfuselagetubeas
shownabove.Thefirewall
doublershouldfitintothe
fuselage with a snug butnot
tightfit.Thefrontofthe
fuselageis cutat a slight
angle sothe firewall and thus
the engine will point down slightly. Because
of this angle the top and bottom edges ofthe
firewall doubler are also cut at a slight angle.
Make sure you install the firewalldoubler so
all of its sides match upnicely with the sides
ofthe fuselage asshown in the sketch.
FIREWALL
DOUBLER
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D2. The 3/8" plywood firewalldoubleris
now glued to the1/4" plywood firewall front.
Use either Thick CA or epoxy and make sure
thatthefront of thefirewalldoubler is
centered on the back of the firewall. Wipe
away allexcessglue that squeezesout.
Tickmarks foralignment
Determinewherethemountshouldbe
installed on thefirewall. Use the template in
the left column to make it easy to locate the
mountingholes.Photocopyor cutoutthe
template and tape it in place on the firewall.
Pokea T-pinthoughthetemplateto
accuratelymarktheboltlocationson the
firewall. Drill a 1/8" diameter hole at the four
pin holes and install the mountusing4-40
bolts, #4 flatwashers and 4-40 blind nuts.
The length of thebolts will be determinedby
the thickness of the firewall. A 1/4" firewall
will usually require7/8" long bolts. Do not
tighten the bolts all theway yet.
D3.Cut orbreak the "spreader bar"off each
mount half. Carefullytrim any extraplasticoff
eachmount half left by the spreader bar.The
surfaces where the spreader bars were attached
need to be very smooth to allow themount
halvesto fittogether.Alsotrim the flashing off
any other rough edges. Snap thetwo mount
halvestogetherasshown inthe sketch.
Slide the mount halves apart until the engine
mountinglugswillsitflaton thebeams.
Adjustthe mountuntilthe firewall centerline
(or offsetline) is centered between the "tick"
marks on the mount.Tighten the 4-40 bolts
toholdthemounthalvesinposition.
Determine how farforward the engine should
be positioned on the beams and mark where
to drillthemountingholes.Removethe
engine and drill a 3/32" hole at each mark.
Put a drop ofoil in each hole and install the
engine using the #4 x 5/8" screws provided.
Ifyou preferto use 4-40 machinescrews (not
included) to install yourengine, just tap the
holesyou drilled with a 4-40 tap.
With the engine installed on the mount,mark
the location for the throttlepushrodand fuel
lines. Remove the engine and mount.Drill a
3/16" hole in the firewall forthe throttleand
two 7/32" holes for the fueland vent lines.
16

end ofthe channel. Square battery packs fit
nicely butmost flat packs will also fit. Just
tape them flatonto the channel. The battery
should protrude approximately 1/8" past the
end ofthe channel to keep the fueltank from
rubbing againstthe end ofthe channel.
D4.Use a small piece ofcoarsesandpaper
to scuff uptheinnerfloor of thealuminum
channel in the area around the front11/64"
bolt hole.
D5.Insertone of the8-32x 1/2" machine
screws intothehole sothatit sticks out the
bottomof thechanneland glue it in place
with plenty of thick C A or epoxy. This screw
willbecoveredbythebatterypack,
prohibiting a screwdriver frombeing used to
keep it from turning.Glue it securely, butbe
careful not to get any glue on the threads.
D6.Use somenylon reinforced strapping tape
to securely hold the battery pack onthe front
D7. Theservosare"pressfit"intothe
aluminum channel and then held in place with
nylonstrappingtape. Standard size servos
should fitvery nicely and smaller servoscan be
held in place by using a piece ofwoodto fill the
space between the servosides and the channel.
LargeservoswillnotworkintheSTURDY
BIRDY II.The servosshould be placed asfar
forward in the channel as possible and right
next to each other, but do not overlap the servo
mounting lugs. The fronttwo servosshould be
mountedwiththeirservo outputshafts
towards the back of theplane and theback
servo should have its outputshaft towards the
frontofthe plane. The servo wires should be
routedoutto theside of theservo without
going underany servos. Wrap two layers of
nylon strapping tape allthe way around each
servoand the aluminum channel to hold it in
place. Hook uptheentireradiosystem and
turn iton (seethe instructions included with
your radio).Adjustthetransmittertrims so
they areinthe middle oftheir slots.
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Remove the screwsthat holdthe servohorns
inplace and adjust the horns sothat they are
perpendicular to the servo. This will be their
neutral position. It isa goodidea to use single
arm servohorns rather than the round horns
most servoscome with. The sketch shows how
tocut a horn for use here. Reinstallthescrews
that hold the horns inplace.
D9.Press thefin/rudderintothechannel
with the back edge of the fin even with the
backedgeof thechannelas shownin
the photo.
D8.Attachthestabilizer/elevatorto the
back of the channelusingtwo 4-40 x 5/8"
machinescrews, two #4flatwashers,two
4-40 lock washers and two 4-40 nuts.
D10.Assemblethetwopushrodsby
screwing a 1"threadedrod intoone end of
each innerpushrodandthenscrewinga
nylon clevisonto each threaded rod. The rod
should thread into both the pushrod and the
clevis at least 13turns.
The sketchshowshowthepiecesare
installed.The prebenttail skid isheld in
placeby the rear screw.D11.Attach the two long pushrods to the
two rear servosasshown in the photo. Slide
18

theouterpushrodtubesovertheinner
pushrod untilthey are about 1/2" from the
servoend ofthe inner pushrod.
D12.Press thebalsa pushrod holder into
the channel about 6"in frontof the finand
secure the pushrods to it with the nylon tie
wrap.Itis a good ideatoseal thebalsa
pushrod holder with a light coat ofepoxy that
will also help hold it in place.
Note: The rudder pushrod goesto the left side
of thefin.The elevator pushrod goesto the
right side(asviewedfrom the back).
DD 13.Cut 2"offthe threaded end of two of
the12"long linkrods. Use a pair of long nose
pliers to bend the "Z"inthe unthreaded end
ofthe 2"pieces.
D14.Install thelinkrods in the2nd hole
from the outer end ofeach control horn.With
thecontrol surfaces and theservo hornsin
their neutralpositions, cut theinnerpushrod
so thelinkrodwillthreadintotheinner
pushrodapproximately2/3oftheway.
Install the link rods into the inner pushrods
and adjust sothatthe control surfaces are at
neutral positions.
D 15.Wrap the receiver in at least 1/4" thick
foam rubber to protect it from vibration, hard
landings, etc. and use two rubber bands to
hold thefoamrubberin place. Disconnect
therudderand elevator pushrodsfromthe
servos and slide thepushrodsunderthe
rubberbandson thetopof thereceiver.
Position thereceiver behind theservos and
reattach the clevisesto the servohorns. The
switchcan be servo tapedto thefuselage
behind the receiver soit can be reached from
the back ofthe fuselage.
The receiverantennashouldexit outthe
backof thefuselagewithoutencountering
anyotherwiresifpossible.Usea small
rubber band to hold the antenna on a T-pin
insertedinthe top ofthe fin.
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D16.Assemble thethrottle (short) pushrod
by screwing the remainingnylon clevis and
1"long threaded rod into one end of the short
innerpushrodand snappingthis assembly
onto the throttle servo horn.
D18.Slide thetwo 1/4" plywood landing
gear supports into the fuselage, one on each
side of the aluminumchannel.The frontof
the supports should be even with the front of
the aluminumchannel.
D17.Attach the plastic fuselage tube to the
channelbyslidingitoverthechannel
assembly and pushingthe front8-32screw
through themiddle hole in the bottom of the
tube. Put the aluminumlanding gear in place
on the8-32 screw andsecurethewhole
assembly with a #8 lock washer and an 8-32
hex nut.Insert the remaining 8-32screw in
the rear hole from the bottom and secure it
with a # 8 lock washer and an 8-32hex nut
in the channel. Itis a good idea to use some
mediumstrength thread locking cement on
these bolts.
D19.Tack glue or hold theseinplace for the
next step.
D20. Drilla 1/8" diameterholein each
support using the attached landing gear asa
guide. Remove the supports from the fuselage
20