Seagull Models HARMON ROCKET III User manual

HARMON ROCKET III
MadeinVietnam.
Kit features.
• Ready-made—minimalassembly&finishingrequired.
• Ready-coveredcovering.
• Photo-illustratedstep-by-stepAssemblyManual.
Specifications
Wingspan----------------------------------------50.4in----------------------------128cm.
Wingarea---------------------------------------558sq.in-----------------------36sq.dm.
Approximate flying weight------------------ 6.2-6.4lbs-------------------- 2.8-2.9kg.
Length--------------------------------------------51.6in----------------------------131cm.
Recommended engine size---------------.40-.46 cu.in-------------------- 2-stroke.
.52-.82 cu.in--------------------4-stroke.
Radio System required 4 channel with 6 servos.
Flying skill level Intermediate/advanced.
Hand-made Almost Ready to Fly R/C Model Aircraft
ASSEMBLY MANUAL

HARMON ROCKET III. Instruction Manual.
2
INTRODUCTION.
ThankyouforchoosingtheHarmonRocketIIIARTFbySEAGULLMODELS.TheHarmonRocket
IIIwasdesignedwiththeintermediate/advancedsportflyerinmind.Itisa semiscale airplane which
is easy to fly and quick to assemble. The airframe is conventionally built using balsa, plywood to
make it stronger than the average ARTF , yet the design allows the aeroplane to be kept light. You
willfindthatmostoftheworkhasbeendoneforyoualready.Flyingthe Harmon RocketIIIissimply
ajoy.
This instruction manual is designed to help you build a great flying aeroplane. Please read this
manualthoroughlybeforestartingassemblyofyour HarmonRocket III.Usethepartslistingbelow
to identify all parts.
WARNING.
Please be aware that this aeroplane is not a toy and if assembled or used incorrectly it is
capable of causing injury to people or property. WHEN YOU FLY THIS AEROPLANE YOU
ASSUME ALL RISK & RESPONSIBILITY.
IfyouareinexperiencedwithbasicR/CflightwestronglyrecommendyoucontactyourR/Csupplier
and join your local R/C Model Flying Club. R/C Model Flying Clubs offer a variety of training
proceduresdesignedtohelpthenewpilotonhiswayto successful R/C flight. They will also be able
to advise on any insurance and safety regulations that may apply.
ADDITIONAL ITEMS REQUIRED.
.40-.46 2-stroke engine
.52-.82 4-stroke engine
Computer radio with six servos
Glow plug to suit engine
Propeller to suit engine
Protective foam rubber for radio
system
Silicone fuel line
TOOLS & SUPPLIES NEEDED.
Thick cyanoacrylate glue
30 minute epoxy
5 minute epoxy
Hand or electric drill
Assorted drill bits
Modellingknife
Straight edge ruler
2mm ball driver
Phillips head screwdriver
220 grit sandpaper
90° square or builder’s triangle
Wire cutters
Masking tape & T-pins
Thread-lock
Paper towels
PARTS LISTING.
FUSELAGE ASSEMBLY
(1) Fuselage
(1) Canopy hatch
WING ASSEMBLY
(1) Right wing half with pre-installed
aileron
(1) Left wing half with pre-installed
aileron
(1) Aluminium dihedral brace
Tail section assembly
(1) Horizontal stabilizer with pre-
installed elevator halves
Some more parts.
HARDWAREPACK
COWLING
Landing gear.....

HARMON ROCKET III. Instruction Manual.
3
NOTE: To avoid scratching your new aero-
planewesuggestthatyoucoveryour
workbench with an old towel. Keep a
couple of jars or bowls handy to hold
the small parts after you open the
bags.
Pleasetrialfitallparts.Makesureyou
have the correct parts and that they
fit and are aligned properly before
gluing! This will ensure proper as-
sembly as the Harmon Rocket III is
made from natural materials and
minor adjustments may have to be
made.
The paint and plastic parts used in
this kit are fuel proof. However, they
arenottolerantofmanyharshchemi-
cals including the following: paint
thinner, cyano-acrylate glue accel-
erator,cyanoacrylategluede-bonder
andacetone.Donot let thesechemi-
calscome incontact withthe colours
onthecoveringand the plasticparts.

HARMON ROCKET III. Instruction Manual.
4
4)Deflect the aileron and completely
saturate each hinge with thin C/A glue. The
aileronsfrontsurfaceshould lightly contact the
wing during this procedure. Ideally, when the
hinges are glued in place, a 1/64” gap or less
will be maintained throughout the lengh of the
aileron to the wing panel hinge line.
Note:
The control surfaces, including the
ailerons, elevators, and rudder, are
prehinged with hinges installed, but the
hinges are not glued in place. It is
imperativethat you properly adhere the
hingesin place per the steps that follow
usinga high-qualitythin C/A glue.
1) Carefully remove the aileron from one
of the wing panels. Note the position of the
hinges.
2)Remove each hinge from thewing panel
and aileron and place a T-pin in the center of
each hinge. Slide each hinge into the aileron
untiltheT-pinis snugagainst the aileron.This
will help ensure an equal amount of hinge is
oneithersideofthehingelinewhentheaileron
is mounted to the wing panel.
HINGINGTHE AILERONS.
Note:
The hinge is constructed of a special
material that allows the C/A to wick or
penetrateanddistributethroughout the
hinge, securely bonding it to the wood
structureof the wingpanel and aileron.
7) Repeat this process with the other wing
panel, securely hinging the aileron in place.
3) Slide the aileron on the wing panel until
there is only a slight gap. The hinge is now
centered on the wing panel and aileron.
Remove the T-pins and snug the aileron
against the wing panel.A gap of 1/64” or less
shouldbe maintained betweenthe wing panel
andaileron.
5) Turn the wing panel over and deflect the
aileron in the opposite direction from the
opposite side. Apply thin C/A glue to each
hinge,makingsure that the C/Apenetratesinto
both the aileron and wing panel.
6) Using C/A remover/debonder and a
papertowel, remove anyexcessC/A glue that
may have accumulated on the wing or in the
aileronhinge area.
C/Aglue.
C/Aglue.
T-pin.
T-pin.

HARMON ROCKET III. Instruction Manual.
5
8)After both ailerons are securely hinged,
firmly grasp the wing panel and aileron to
make sure the hinges are securely glued and
cannot be pulled out. Do this by carefully
applying medium pressure, trying to separate
the aileron from the wing panel. Use caution
not to crush the wing structure.
Note:Work the aileron up and down several
times to “work in” the hinges and check
for proper movement.
1) Carefully remove the elevator from one
of the horizontal stabilizer panels. Note the
position of the hinges.
2) Remove each hinge from the horizontal
stabilizerpaneland elevator andplace a T-pin
in the center of each hinge. Slide each hinge
intothe elevatoruntil theT-pinis snug against
the elevator. This will help ensure an equal
amount of hinge is on either side of the hinge
line when the elevator is mounted to the
horizontal stabilizer panel.
4)Deflect the elevator and completely
saturate each hinge with thin C/A glue. The
elevators front surface should lightly contact
thehorizontal stabilizer during this procedure.
Ideally, when the hinges are glued in place, a
1/64”gaporlesswillbemaintainedthroughout
the lengh of the elevator to the horizontal
stabilizer panel hinge line.
Note: The hinge is constructed of a special
material that allows the C/A to wick or
penetrateanddistributethroughout the
hinge, securely bonding it to the wood
structure of the horizontal stabilizer
paneland elevator.
5) Turn the horizontal stabilizer panel over
and deflect the elevator in the opposite
directionfromthe opposite side.ApplythinCA
glue to each hinge, making sure that the C/A
penetratesintoboth the elevatorandhorizontal
stabilizer panel.
HINGINGTHE ELEVATORS.
3) Slide the elevator on the horizontal
stabilizer panel until there is only a slight gap.
The hinge is now centered on the horizontal
stabilizer panel and elevator. Remove the T-
pins and snug the elevator against the
horizontal stabilizer panel. A gap of 1/64” or
less should be maintained between the
horizontal stabilizer panel and elevator.
C/Aglue.
6) Using C/A remover/debonder and a
papertowel, remove anyexcessC/A glue that
may have accumulated on the horizontal
stabilizer or in the elevator hinge area.
8) After both elevator are securely hinged,
firmlygrasp the horizontalstabilizer panel and
elevatorto makesure thehinges aresecurely
glued and cannot be pulled out. Do this by
carefully applying medium pressure, trying to
separate the elevator from the horizontal
stabilizer panel. Use caution not to crush the
horizontal stabilizer structure.
7) Repeat this process with the other
horizontalstabilizerpanel,securelyhingingthe
elevator in place.

HARMON ROCKET III. Instruction Manual.
6
4)Deflect the rudder and completely
saturate each hinge with thin C/A glue. The
rudder front surface should lightly contact the
fuselage during this procedure. Ideally, when
the hinges are glued in place, a 1/64” gap or
less will be maintained throughout the lengh
of the rudder to the fuselage panel hinge line.
1) Carefully remove the rudder from one of
the fuselage panel. Note the position of the
hinges.
2) Remove each hinge from the fuselage
panelandrudderandplaceaT-pininthecenter
ofeachhinge.Slide each hinge intotherudder
until the T-pin is snug against the rudder. This
will help ensure an equal amount of hinge is
oneithersideofthehingeline when the rudder
is mounted to the fuselage panel.
Note: The hinge is constructed of a special
materialthat allowstheC/Atowick orpenetrate
and distribute throughout the hinge, securely
bondingittothewoodstructureofthe fuselage
panel and rudder.
3) Slide the rudder on the fuselage panel
until there is only a slight gap. The hinge is
nowcenteredonthefuselagepanelandrudder.
Remove the T-pins and snug the rudder
against the fuselage panel. A gap of 1/64” or
less should be maintained between the
fuselage panel and rudder.
5)Turnthefuselage panelover and deflect
the rudder in the opposite direction from the
opposite side. Apply thin C/A glue to each
hinge,makingsure that the C/Apenetratesinto
the rudder and fuselage panel.
6) Using C/A remover/debonder and a
papertowel, remove anyexcessC/A glue that
may have accumulated on the fuselage or in
the rudder hinge area.
HINGINGTHERUDDER.
C/Aglue.
C/Aglue.
Hinge.
Hinge.
Note:Work the rudder left and right several
times to “work in” the hinges and check
for proper movement.

HARMON ROCKET III. Instruction Manual.
7
Expoxy.
2) Remove the brace when satisfied with
its fit ineach wing half. Coat both sides of one
halfofthedihedralbracewith30minuteepoxy.
Next,poursomeepoxyintothedihedralboxin
one wing panel. Make sure you cover the top
andbottomaswellasthesidesofthedihedral
brace. Use enough epoxy to fill any gaps.
 1)Testfitthewingtubeintoeachwinghalf.
The brace should slide in easily up to the
centreline that you drew.If not, use 220 grit
sandpaper with a sanding block and sand
down the edges and ends of the brace until it
fits properly.
Maskingtape.
WING ASSEMBLY.
NOTE: We highly recommend using 30
minute epoxy as it is stronger and provides
more working time, allowing the builder to
properlyalignthe parts. Usingfastcureepoxy
whenjoiningthewinghalvescouldresultinthe
gluedryingbeforethewinghalvesarealigned
properlywhichmayresultinfailureofthewing
centre section during flight.
 3) Peel off the backing from the self adhe-
sivecoveringstrip.Applythestriptothecentre
section of the wing starting from the bottom
trailingedge.Wrapthestripallthewayaround
the wing until it meets the trailing edge again.
Trim off any excess strip.
Carefully slide the two wing halves together
and firmly press them together, allowing the
excess epoxy to run out. There should not be
any gap in the wing halves. Use rubbing
alcohol and a paper tower to clean up any
excess epoxy.
Apply masking tape at the wing join to hold
the wing halves together securely.
Centreline.
Maskingtape.

HARMON ROCKET III. Instruction Manual.
8
Attach servo lead to the aileron servo.Attach
thestring tothe servo leadandcarefullythread
it though the wing. Once you have thread the
leadthrought the wing,remove the string soit
canuse fortheotherservolead.Tape theservo
lead to the wing to prevent it from falling back
into the wing.
We recommended to use long ser-
vosarm for all servos without throttle
servo.
Because the size of servos differ,
you may need to adjust the size of the
precut opening in the mount. The notch
in the sides of the mount allow the servo
lead to pass through.
Install the rubber grommets and brass
colletsonto the aileronservo. Test fit the servo
into the aileron servo mount.
Install the servo into the servo tray.
Using a small weight (Weighted fuel pick-up
workswell) and thread, feedthestring through
the wing as indicated.
Small weight.
Thread.
Wing bottom.
INSTALLING THE AILERON SERVOS.
Remove covering.
Glueattached.
Servo.
Small weight.
Thread.

HARMON ROCKET III. Instruction Manual.
9
AILERON LINKAGE.
INSTALLING THEAILERON LINKAGE.
1) Using a ruler & pen to draw a straight
line as below picture.
Install the aileron servo tray into the servo
mount.
Repeat the procedure for orther wing
haft.
Thread.
Pen.
Straight line.
Servo arm.
Thread.
Thread.
Small weight.
Plastic tape.

HARMON ROCKET III. Instruction Manual.
10
4) Using a 1mm drill bit and the control
horns as a guide, drill the mounting holes
through the aileron halves.
5) Mount the control horns by inserting
thescrewsthroughthe control horn basesand
aileron halves, then into the mounting
backplates. Do not overtighten the screws or
the backplates may crush the wood.
6) Thread one nylon adjustable control
hornontoeach aileron control rod. Threadthe
horns on until they are flush with the ends of
the control rods. Repeat the procedure for the other
aileron servo.
Cut.
M2 lock nut. Snapkeepper.
M2clevis.
2) Locate the two nylon control horns,
two nylon control horn backplates and two
machine screws.
ControlHorn.
MountingScrews. Mounting Plate.
2MMx30 MM.
3) Position the aileron horn on the bottom
side of aileron. The clevis attachment holes
should be positioned over the hinge line.
Pen.
Aileron pushrod rod.
Clevis.

HARMON ROCKET III. Instruction Manual.
11
M4.
ENGINE MOUNT.
See pictures below:
1) Using a modeling knife, carefully cut
offthe rearportionofoneofthe twonylontubes
leaving 1/2” protruding from the rear of the
stopper. This will be the fuel pick up tube.
2) Usinga modeling knife, cut onelength
of silicon fuel line . Connect one end of the
line to the weighted fuel pickup and the other
end to the nylon pickup tube.
3) Carefully bend the second nylon tube
up at a 45º angle. This tube is the vent tube.
4) Carefully heat the vent tube using a
heat gun or lighter to permanently set the
angle of the tube.
Silicon tubing not inclued.
Venttube. Fuel Pickup
Tube.
FuelFill Tube.
Important: When the stopper assembly is
installed in the tank, the top of the vent tube
should rest just below the top surface of the
tank. It should not touch the top of the tank.
When the stopper assembly is installed in the
tank, the top of the vent tube should rest just
below the top surface of the tank. It should
not touch the top of the tank.
5) Test fit the stopper assembly into the
tank. It may be necessary to remove some of
INSTALLING THE STOPPERASSEMBLY.
FUEL TANK.

HARMON ROCKET III. Instruction Manual.
12
 1) Install the pushrod housing through the
predrilledholein the firewallandintothe servo
compartment. The pushrod housing should
protrude 1/4" out past the front of the firewall.
You should mark which tube is the vent
and which is the fuel pickup when you
attach fuel tubing to the tubes in the stopper.
Once the tank is installed inside the fuselage,
it may be difficult to determine which is which.
Slide the tank into the fuselage from inside so
that the neck is at the top of the fuselage and
itlocates through theengine bulkhead. Gently
secure it to the top horizontal former with a
cable tie.
MOUNTING THE ENGINE.
PARTSREQUIRED
Blow through one of the lines to ensure
thefuel lines havenot becomekinked in-
sidethefueltankcompartment. Airshouldflow
througheasily.
Make a Z-Bend 1/4" from one end of the plain
wire pushrod.
 2) Place your engine onto the engine
mount. Adjust the engine is centered of the
edges of the engine case.
4) Remove the engine. Using an drill bit,
drill the mounting holes through the engine
mount at the four locations marked.
 3) When you are satisfied with the align-
ment, mark the locations of the engine
mounting.
insidethetank. Thetopoftheventtubeshould
rest just below the top of the tank. It should
not touch the top of the tank.
7) When satisfied with the alignment of
thestopperassemblytightenthe3mm x 20mm
machine screw until the rubber stopper ex-
pands and seals the tank opening. Do not
overtighten the assembly as this could cause
the tank to split.
the flashing around the tank opening using a
modeling knife. If flashing is present, make
sure none falls into the tank.
6) With the stopper assembly in place,
the weighted pickup should rest about 3/8”
awayfromthe rear of thetankand move freely
Fuel tank.
Fuel fill tube.
Fuel pickup
tube.
Vent tube.
11.3cm.
EVOLUTION
Engine.46.

HARMON ROCKET III. Instruction Manual.
13
 5) Bolt the engine to the engine mount
using the four machine screws and lock
washer. Double cheek that all the screws are
tight before proceeding.
 6) AttachtheZ-Bend inthe pushrod wire
to the throttle arm on the carburetor. You will
need to remove the throttle arm from the car-
buretor to be able to attach the Z-bend. When
complete, reattach the throttle arm to the car-
buretor.
4mm X 30mm.
4.2- 4.5mm.
Pushrodwire.
COWLING.
1) Slide the fiberglass cowl over the en-
gineandline up thebackedge of the cowlwith
themarks you made on thefuselage thentrim
and cut.
2) Whilekeeping the back edge of the cowl
flushwith the marks,align the frontof thecowl
withthe crankshaft of the engine. The front of
the cowl should be positioned so the crank-
shaft is in nearly the middle of the cowl open-
ing.Usethespinner backplate as a guide.Hold
the cowl firmly in place using pieces of mask-
ingtape.
Trim and cut.
Trim and cut.
Trim and cut.
Because of the diameter of the cowl, it
may be necessary to use a needle valve ex-
tensionforthe high speed needlevalve. Make
this out of sufficient length 1.5mm wire and
install it into the end of the needle valve. Se-
cure the wire in place by tightening the set
screw in the side of the needle valve.

HARMON ROCKET III. Instruction Manual.
14
3) Slide the cowl back over the engine
andsecure it inplace usingfour 3mm x12mm
wood screws. See picture below.
4) Installthemufflerandmufflerextension
onto the engine and make the cutout in the
cowl for muffler clearance. Connect the fuel
and pressure lines to the carburetor, muffler
andfuel filler valve.
1.5mm wire
(needlevalve).
1)Installthespinnerbackplate,propellerand
spinner cone. The spinner cone is held in
place using two 3mm x 12mm wood screws.
The propeller should not touch any part
of the spinner cone. If it does, use a
sharp modeling knife and carefully trim away
the spinner cone where the propeller comes
in contact with it.
INSTALLING THE SPINNER.
Machine screw
3mm X 12mm.

HARMON ROCKET III. Instruction Manual.
15
(2)Wheel Collar.
Axle.
Wheel. Nut.
Nut.
(2)Washer.
46mm.
WHEEL AND WHEEL PANTS.
PARTSREQUIRED
1) Assembling and mounting the wheel
pants as shown below pictures.
2) Follow diagram below for wheel pant
installation:
10MM.
3) You have to trim each axle using a toll
cutting and cut-off wheel.
Cautionwhen cuttingthe axles and wear
protective goggles.
WheelCollar.
Axle.
Wheel. Nut.
Wheel Pant.
LandingGear.
Nut.
Plywood Washer.

HARMON ROCKET III. Instruction Manual.
16
HORIZONTAL STABILIZER.
1) Using a ruler and a pen, locate the
centerlineof thehorizontalstabilizer,atthetrail-
ing edge, and place a mark. Use a triangle
and extend this mark, from back to front,
across the top of the stabilizer. Also extend
this mark down the back of the trailing edge
of the stabilizer.
3)Secure theservos with the screws pro-
vided with your radio system.
1) Locate and cut out the covering film
fromthe servo holesin bothsides of fuselage.
ELEVATOR - RUDDER SERVO
INSTALLATION.
2) Installthe rubber grommets and brass
colletsonto the aileronservo. Test fit theservo
into the aileron servo mount.
Because the size of servos differ, you may
need to adjust the size of the precut opening
in the mount. The notch in the sides of the
mount allow the servo lead to pass through.
 4) A drop of C/A glue on the wheel collar
screws will help keep them from coming lose
duringoperation.
Repeat the process for the other wheel.
1) The blind nuts for securing the landing
gearare already mountedinside the fuselage.
2) Usingthe hardware provided, mount the
main landing gear to the fuselage.
INSTALLING THE MAIN LANDING GEAR.
4mm X 20mm.
Left side.
Elevatorservo.
Rudder servo.
Right side.
Elevatorservo.

HARMON ROCKET III. Instruction Manual.
17
Pen.
2)Usingamodelingknife,carefullyremove
thecoveringat mounting slotof horizontal sta-
bilizer ( both side of fuselage).
 3) Slidethestabilizerintoplacein thepre-
cut slot in the rear of the fuselage. The stabi-
lizer should be pushed firmly against the front
of the slot.
When cutting through the covering to remove
it, cut with only enough pressure to only cut
through the covering itself. Cutting into the
balsa structure may weaken it.
 5) Remove the stabilizer. Using the lines
youjust drew as a guide,carefully removethe
covering from between them using a model-
ingknife.
Centerline.
 4) With the stabilizer held firmly in place,
use a pen and draw lines onto the stabilizer
where it and the fuselage sides meet. Do this
on both the right and left sides and top and
bottom of the stabilizer.
 6) Using a modeling knife, carefully re-
move the covering that overlaps the stabilizer
mounting platform sides in the fuselage. Re-
move the covering from both the top and the
bottom of the platform sides.
Remove covering.
 8) After the epoxy has fully cured, re-
movethe masking tape or T-pins used tohold
the stabilizer in place. Carefully inspect the
glue joints. Use more epoxy to fill in any gaps
that may exist that were not filled previously
and clean up the excess using a paper towel
and rubbing alcohol.
 7) When you are sure that everything is
aligned correctly, mix up a generous amount
of 30 Minute Epoxy. Apply a thin layer to the
topand bottom ofthe stabilizer mountingarea
and to the stabilizer mounting platform sides
in the fuselage. Slide the stabilizer in place
and realign. Double check all of your mea-
surementsoncemore before theepoxycures.
Holdthestabilizerin place withT-pinsormask-
ing tape and remove any excess epoxy using
a paper towel and rubbing alcohol.
Remove covering.

HARMON ROCKET III. Instruction Manual.
18
3) While holding the vertical stabilizer
firmly in place, use a pen and draw a line on
each side of the vertical stabilizer where it
meets the top of the fuselage.
4) Remove the stabilizer. Using a mod-
eling knife, remove the covering from below
the lines you drew. Also remove the covering
from the bottom edge of the stabilizer and the
bottomandtopedges of thefillerblock. Leave
the covering in place on the sides of the filler
block.
When cutting through the covering to re-
moveit, cut with only enough pressure to only
cutthroughthe covering itself. Cuttingintothe
balsa structure may weaken it.
Pen.
VERTICAL STABILIZER
INSTALLATION.
2) Slidethe vertical stabilizer into theslot
in the top of the fuselage. The rear edge of
thestabilizer shouldbe flushwiththerearedge
of the fuselage and the lower rudder hinge
should engage the precut hinge slot in the
lowerfuselage. The bottom edge of thestabi-
lizer should also be firmly pushed against the
top of the horizontal stabilizer.
1) Using a modeling knife, remove the
covering from over the precut hinge slot cut
intothelowerrearportionofthefuselage. This
slot accepts the lower rudder hinge.
Hingeslot.
Remove covering.
Covered wood
fillerpiece.

HARMON ROCKET III. Instruction Manual.
19
 2) Position the elevator horn on the both
sideof elevator.The clevis attach-mentholes
should be positioned over the hinge line.
5) Slide the vertical stabilizer back in
place. Using a triangle, check to ensure that
thevertical stabilizer is aligned 90ºto the hori-
zontal stabilizer.
6) When you are sure that everything is
alignedcorrectly,mixupagenerousamountof
Flash30MinuteEpoxy. Applyathinlayerto the
mounting slot in the top of the fuselage and to
the sides and bottom of the vertical stabilizer
mountingarea. Applyepoxytothebottom and
top edges of the filler block and to the lower
hinge also. Set the stabilizer in place and re-
align. Double check all of your measurements
once more before the epoxy cures. Hold the
stabilizer in place with T-pins or masking tape
and remove any excess epoxy using a paper
towel and rubbing alcohol. Allow the epoxy to
fully cure before proceeding.
 3) Using a 1.5mm drill bit and the control
horns as a guide, drill the mounting holes
through the elevator halves.
ControlHorn.
MountingScrews. Mounting Plate.
4) Mount the control horns by inserting the
bolts through the control horn bases and
elevator halves, then into the mounting
backplates. Do not overtighten the nuts or the
backplates may crush the wood.
5) Position the rudder control horn on the
leftsideoftheairplane.Mount the control horn
parallel with the horizontal stabilizer.
 6) Install the rudder control hornusing the
same method as with the elevator control
horns.
2MM x 20MM.
C/Aglue.
90º
Vertical
Stabilizer.
Horizontal
Stabilizer.
CONTROL HORN INSTALLATION.
 1) Locate the two nylon control horns, two
nylon control horn backplates and four
machine screws.
Elevatorcontrol horn.

HARMON ROCKET III. Instruction Manual.
20
 1) Set the tail wheel assembly in place on
the plywood plate. The pivot point of the tail
wheel wire should be even with the rudder
hinge line and the tail wheel bracket should
be centered on the plywood plate.
 2 Using a pen, mark the locations of the
two mounting screws. Remove the tail wheel
bracket and drill 1mm pilot holes at the loca-
tions marked.
MOUNTING THE TAIL WHEEL BRACKET.
 3) Secure the tail wheel bracket in place
using two 3mm x 15mm wood screws. Be
careful not to overtighten the screws.
 1) Alignthetailwheelwiresothat the wire
is parallel with the bottom of the rudder. The
controlclasp hasa predrilledhole throughthe
topofit. Slide this holeontothe tail wheelwire
while sliding the clasp over the bottom of the
rudder.
MOUNTING THE CONTROL CLASP.
 2) Using a ruler and a pen place a mark
onto the bottom of the rudder, in front of the
rearedgeofthetailwheelwire. Thebackedge
of the clasp should line up with this mark.
Youmayfinditnecessarytobend the tailwheel
wire down slightly so it lines up with the clasp
withoutbinding.
 5) Rudder pushrods assembly follow
picture below.
 3) While holding the clasp firmly in place,
use a pen and outline the clasp onto the rud-
der.
 4) Remove the clasp, and using a model-
ing knife, remove the covering from inside the
lines you drew. Use 220 grit sandpaper and
carefullyroughen theinside surfaceof theny-
lon clasp.
4) One at a time, hold the pushrods in po-
sition over the respective servos to check for
proper servo direction. If any servo turns in
the wrong direction, switch your radio’s re-
versingswitches as necessaryto achieve the
correct direction.
2) Elevator pushrods assembly follow
pictures below.
M2 lock nut. Snapkeepper.
M2clevis.
3) Connect the elevator and rudder servos
to your radio’s receiver and turn on the sys-
tem. Set the trim tabs on the transmitter to
neutraland centerthe servoarms. The eleva-
tor and rudder servo arms should be perpen-
dicular to the servos.
Elevator pushrod.
Pushrod.
Controlhorn.
Connector.
Metalclevis.
1) Thread one nylon adjustable control
horn on to each aileron control rod. Thread
the horns on until they are flush with the ends
of the control rods.
ELEVATOR-RUDDER PUSHROD INSTALLATION.
Rudder control horn.
Elevatorcontrol horn.