Seagull Models Extra 260 User manual

Kit features.
• Ready-made—minimalassembly&finishingrequired.
• Ready-coveredcovering.
• Photo-illustratedstep-by-stepAssemblyManual.
MadeinVietnam.
Specifications
Wingspan------------------------------63in--------------------------160cm.
Wingarea-----------------------------728sq.in------------------47sq.dm.
Weight----------------------------------8.4-9.9lbs-----------------3.8-4.5kg.
Length----------------------------------59.4in-------------------------151cm.
Recommendedenginesize------.91-1.25cu.in-----------2-4stroke.
RadioSystemrequired6channel with6digital servos.
Flyingskilllevel--------------------Intermediate/advanced.
ASSEMBLY MANUAL
MS:56H

EXTRA 260. Instruction Manual.
2
INTRODUCTION.
Thank you for choosing the EXTRA 260 ARTF by SEAGULL MODELS. The EXTRA 260 was
designed with the intermediate/advanced sport flyer in mind. It is a semi scale airplane which is
easytoflyandquicktoassemble.Theairframeisconventionallybuiltusingbalsa,plywood tomake
itstrongerthantheaverageARTF,yetthedesignallowstheaeroplanetobekeptlight.Youwillfind
that most of the work has been done for you already.Flying the EXTRA 260 is simply a joy.
This instruction manual is designed to help you build a great flying aeroplane. Please read this
manual thoroughly before starting assembly of your EXTRA 260. Use the parts listing below 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.
If you are inexperienced with basic R/C flight we strongly recommend you contact your R/C
supplierandjoinyourlocalR/CModelFlyingClub.R/CModelFlyingClubsofferavarietyoftraining
proceduresdesignedtohelpthenewpilotonhiswaytosuccessfulR/Cflight.Theywillalsobeable
to advise on any insurance and safety regulations that may apply.
ADDITIONAL ITEMS REQUIRED.
!.91-1.25 2-4 stroke engine.
!Computer radio with six digital
servos.
!Glow plug to suit engine.
!Propeller to suit engine.
!Protective foam rubber for radio
system.
!Siliconefuel line.
PARTS LISTING.
FUSELAGE ASSEMBLY
!(1) Fuselage.
!(1) Canopy hatch.
WING ASSEMBLY
!(1) Right wing half/ aileron.
!(1) Left wing half/ aileron.
!(1) Aluminium dihedral brace.
HorizonHobby,Inc. guarantees this kit to be freefrom defectsin both material and workmanship
at the date of purchase. This warranty does not cover any parts damage by use or modification. In
nocaseshall Horizon Hobby’sliability exceed theoriginalcost of thepurchasedkit. Further,Horizon
Hobby reserves the right to change or modify this warranty without notice. In that Horizon Hobby
has no control over the final assembly or material used for the final assembly, no liability shall be
assumednoracceptedforanydamageresulting from the usebytheuserofthefinaluser-assembled
product. By the act of using the user-assembled product, the user accepts all resulting liability.
Once assembly of the model has been started, you must contact Horizon Hobby, Inc. directly
regardinganywarranty questionthatyouhave.Pleasedonotcontactyour local hobbyshopregarding
warranty issues, even if that is where you purchased it. This will enable Horizon to better answer
your questions and service you in the event that you may need any assistance. If the buyer is not
prepared to accept the liability associated with the use of this product, the buyer is advised to
return this kit immediately in new and unused condition to the place of purchase.
HorizonHobby
4105 Fieldstone Road
Champaign,Illinois 61822
[phone]

www.seagullmodels.com
3
Please contact Horizon Hobby for product support
and technical assistance at 877-504-0233.
Replacement parts are available from your local
dealer or through Horizon Hobby.
HORIZON HOBBY DISTRIBUTIONS INC
4105Fieldstone Rd,Champaign, IL61822-USA
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.
To avoid scratching your new aeroplane
we suggest that you cover your workbench
with an old towel. Keep a couple of jars or
bowls handy to hold the small parts after you
open the bags.
Please trial fit all parts. Make sure you
havethecorrectparts and thattheyfitand are
alignedproperlybeforegluing!Thiswillensure
proper assembly as the EXTRA 260 is made
from natural materials and minor adjustments
may have to be made.
The paint and plastic parts used in this
kitarefuelproof.However,theyarenottolerant
of many harsh chemicals including the follow-
ing: paint thinner, cyano-acrylate glue accel-
erator, cyanoacrylate glue de-bonder and
acetone. Do not let these chemicals come in
contact with the colours on the covering and
the plastic parts.
Tail section assembly
!(1) Horizontal stabilizer/ elevator
halves.
!(1) Rudder halves.
Some more parts.
HARDWAREPACK
COWLING
Landinggear.....
NOTE.

EXTRA 260. Instruction Manual.
4
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 youproperly adhere the
hingesin placeper the steps that follow
using a high-quality thin C/A glue.
!1) Carefully remove the aileron from one
of the wing panels. Note the position of the
hinges.
!2)Removeeach hinge fromthewingpanel
and aileron and place a T-pin in the center of
each hinge. Slide each hinge into the wing
panel until the T-pin is snug against the wing
panel. This will help ensure an equal amount
ofhingeison either sideofthehinge line when
the wing panel is mounted to the aileron.
HINGING THE AILERONS.
Note:
!3) Slide the wing panel on the aileron 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 wingpanel
andaileron.
!4)Deflect the aileron and completely
saturate each hinge with thin C/A glue. The
aileronsfrontsurfaceshould lightly contactthe
wing during this procedure. Ideally, when the
Hinge.
T-pin.
Hinge.
T-pin.
T-pin.
!5)Turnthe wingpanel over and deflect the
aileron in the opposite direction from the
opposite side. Apply thin C/A glue to each
hinge,makingsurethat the C/A penetrates into
both the aileron and wing panel.
The hinge is constructed of a special
material that allows the C/A to wick or
penetrateanddistribute throughout the
hinge, securely bonding it to the wood
structureof the wingpanel and aileron.
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:
T-pin.
C/Aglue.

www.seagullmodels.com
5
Work the aileron up and down several
times to “work in” the hinges and check
for proper movement.
HINGING THE ELEVATOR.
Note:
!8)Afterbothailerons are securelyhinged,
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.
!7) Repeat this process with the other wing
panel, securely hinging the aileron in place.
!6)UsingC/Aremover/debonderandapaper
towel, remove any excess C/A glue that may
haveaccumulatedonthe wing orintheaileron
hingearea.
C/Aglue.
HINGING THE RUDDER.
Glue the elevator hinges in place using the
same tectniques used to hinge the ailerons.
Glue the rudder hinges in place using the
same tectniques used to hinge the ailerons.
ENGINE MOUNT.
See pictures below:
Mark and drill 4 holes for engine mount.
4x30mm.
!1) Using a modeling knife, carefully cut
off the rear portion of one of the 3 nylon tubes
leaving 1/2” protruding from the rear of the
stopper. This will be the fuel pick up tube.
!2) Usinga modeling knife, cut onelength
ofsilicon fuel line. Connectoneend oftheline
tothe weightedfuel pick up andthe otherend
to the nylon pick up tube.
INSTALLING THE STOPPERASSEMBLY.
FUEL TANK.

EXTRA 260. Instruction Manual.
6
Venttube.
FuelPick-upTube.
FuelFill Tube.
Carefully use a lighter or heat gun to
permenently set the angle of the vent 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.
!4) Test fit the stopper assembly into the
tank. It may be necessary to remove some of
the flashing around the tank opening using a
modeling knife. If flashing is present, make
sure none falls into the tank.
!5) With the stopper assembly in place,
the weighted pick-up should rest away from
therear of the tank and move freely insidethe
tank. The top of the vent tube should rest just
below the top of the tank. It should not touch
the top of the tank.
!6) When satisfied with the alignment of
thestopperassemblytightenthe3mmx20mm
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.
You should mark which tube is the vent
and which is the fuel pick-up when you attach
fuel tubing to the tubes in the stopper. Once
thetank isinstalled inside the fuselage, itmay
be difficult to determine which is which.
Attach the silicone fuel and pressure pipes
tothetank. The lowerpipeis the‘feed’and the
uppertwo the ‘pressureand fill’.The fill pipeis
the next pipe.
Balsa wood.
!3) Carefully bend the second nylon tube
up at a 45º angle. This tube is the vent tube.
Rubber band.
Balsa wood.
Fueltank.

www.seagullmodels.com
7
Fuel pick-up
tube. Fuelfill tube.
Venttube.
Blow through one of the lines to ensure
the fuel lines have not become kinked inside
the fuel tank compartment. Air should flow
through easily.
!1) Locateandcutoutthe covering film from
the servo holes in both sides of fuselage.
!2) Installthe rubbergrommets and brass
collets onto the elevator servo. Test fit the
servo into the elevator servo mount.
!3)Secure theservos withthe screws pro-
vided with your radio system.
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.
Remove covering.
Rightside.
Elevator servo.
Left side.
Elevator servo.
INSTALLING THE FUSELAGE SERVO.
Throttle servo.
Rudder servo.
Servo tray.
Engine .91 - 2 stroke.
Engine 1.25 - 4 stroke.
We recommended to use long servos arm
(70mmdiameter) forallservoswithoutthrottle
servo.
ELEVATOR SERVO INSTALLATION.
C/Aglue.

EXTRA 260. Instruction Manual.
8
Wing bottom.
Thread.
Small weight.
Thread. Small weight.
INSTALLING THE SWITCH.
Remove covering.
Switch.
Installthe switch intothe precut holein the
side, in the fuselage.
Because the size of servos differ, you
mayneedtoadjustthesize of the precut open-
ing in the mount. The notch in the sides of
themountallowtheservoleadtopassthrough.
INSTALLING THE AILERON SERVOS.
We recommended to use long servos arm
(70mmdiameter) forallservoswithoutthrottle
servo.
Install the rubber grommets and brass
collets onto the aileron servo. Test fit the
servo into the aileron servo mount.
Using a small weight (Weighted fuel pick-up
workswell) and thread, feedthe string through
the wing as indicated.
Rudder servo.
Throttle servo.
Servos. Thread.
Small weight.

www.seagullmodels.com
9
Wing bottom.
HORIZONTALSTABILIZER.
Attach the string to the servo lead and
carefully thread it though the wing. Once you
havethreadthe leadthroughtthewing,remove
the string so it can use for the other servo
lead.Tapetheservoleadtothewingtoprevent
it from falling back into the wing.
Electric wire. Thread.
Repeat the procedure for orther wing
haft.
Plastic tape.
Aileronelectric.
Wing panel bottom.
Thread.
Electric wire.
Pull.
Secure the servos with the screws pro-
vided with your radio system.
!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
thismark downthe back of the trailing edge of
the stabilizer.
!2)Usinga modeling knife, carefully remove
thecoveringat mountingslotof horizontal sta-
bilizer ( both side of fuselage).
Center line.
! 3) Slide the stabilizer into place in the pre-
cut slot in the rear of the fuselage. The stabi-
lizer should be pushed firmly against the front
of the slot.

EXTRA 260. Instruction Manual.
10
! 8) After the epoxy has fully cured, re-
move the masking tape orT-pins used to hold
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.
Covered wood
filler piece.
Remove covering.
! 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 stabilizermounting area
and to the stabilizer mounting platform sides
in the fuselage. Slide the stabilizer in place
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.
! 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.
Removecovering.
! 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.
! 5) Remove the stabilizer. Usingthe lines
youjust drewas a guide, carefully removethe
covering from between them using a model-
ingknife.
Pen.
and realign. Double check all of your mea-
surementsoncemore beforetheepoxy cures.
HoldthestabilizerinplacewithT-pinsormask-
ing tape and remove any excess epoxy using
a paper towel and rubbing alcohol.
Hinge.
VERTICAL STABILIZER INSTALLATION.

www.seagullmodels.com
11
Hingeslot.
!1) Using a modeling knife, remove the
covering from over the precut hinge slot cut
intothelowerrearportionofthe fuselage. This
slot accepts the lower rudder hinge.
!2) Slidethe verticalstabilizer 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 bottomedge of the stabi-
lizer should also be firmly pushed against the
top of the horizontal stabilizer.
!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.
When cutting through the covering to re-
moveit, cut with only enoughpressure to only
cut through the covering itself. Cutting into
the balsa structure may weaken it.
Remove
covering.
!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
bottomandtop edges of thefillerblock. Leave
the covering in place on the sides of the filler
block.
Pen.
!6) When you are sure that everything is
alignedcorrectly,mixupa generous amount of
30MinuteEpoxy. Applyathinlayertothemount-
ingslotinthetopofthefuselageandtothesides
!5) Slide the vertical stabilizer back in
place. Using a triangle, check to ensure that
thevertical stabilizeris aligned 90ºto thehori-
zontal stabilizer.
90º
Vertical
Stabilizer.
Horizontal
Stabilizer.
and bottom of the vertical stabilizer mounting
area. Applyepoxy tothebottomand top edges
of the filler block and to the lower hinge also.
Set the stabilizer in place and realign. Double
checkallofyourmeasurements once more be-
foretheepoxycures.Holdthestabilizerinplace
with T-pins or masking tape and remove any
excess epoxyusing a paper toweland rubbing
alcohol. Allow the epoxy to fully cure before
proceeding.

EXTRA 260. Instruction Manual.
12
INSTALLING THE AILERON LINKAGE.
!
1) Aileron control horn:
Mix a small amount of 30 minute epoxy and
lightly coat the inside of the hole in the aileron
and the control horn screw.
! 2) Thread the screw (insert the aluminium
washer) into the hole from the top of surface.
Wipeaway any excessepoxy on thewing and
screwwith rubbingalcohol anda papertowel.
Screw the M3 nut (insert the aluminium
washer) in place as shown. Alllow the epoxy
to fully cure.
Wing.
Aileron.
Aluminiumwasher.
M3 nut.
M3 lock nut.
Wing bottom.
M3control horn.
Wing bottom.
Aileroncontrol horn.
Repeat the procedure for orther wing.
3x45mm.
C/Aglue.
ELEVATORCONTROLHORNINSTALLATION.
! 1) Elevator control horn:
Mix a small amount of 30 minute epoxy and
lightlycoattheinside of theholeinthe elevator
and the control horn screw.
!
2)Thread the screw(insert thealuminium
washer) into the hole from the top of surface.
Wipe away any excess epoxy on the fin and
screwwith rubbingalcohol anda papertowel.
Screw the M3 nut (insert the aluminium
washer) in place as shown. Alllow the epoxy
to fully cure.
Horizontalfin.
Elevator.
Elevator control horn.

www.seagullmodels.com
13
Repeat the procedure for orther
elevator.
!1) Position the rudder control horn on the
left - right side of the rudder.
! 2) Locate the two nylon control horns, two
nylon control horn backplates and three
machine screws.
3x30mm.
2x30mm.
RUDDER CONTROL HORN
INSTALLATION.
Rudder
control horn.
!5) 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.
! 3) Position the rudder horn on the both
side of rudder. The clevis attach- ment holes
should be positioned over the hinge line.
! 4) Using a 1.5mm drill bit and the control
horns as a guide, drill the mounting holes
through the rudder halves.
Rudder
control horn.
AILERON PUSHROD INSTALLATION.
Pushrod.
55mm.
C/Aglue.
M3lock nut.
Aileron pushrods assembly follow pictures
below.

EXTRA 260. Instruction Manual.
14
! 2) With the radio on, check the operation
of the rudder. Adjust the cables so when the
rudder servo is centered, the rudder is
centered as well. There will be tension on the
cables.Adjustmentscanbemadeattherudder
control horn and at the servo arm. Once
Left side.
Cable.
adjustments are made, secure the servo arm
to the rudder arm servo using the screw that
came with the servo
Pushrod.
Cable.
Metalclevis. Control horn.
Elevator pushrod.
Repeat the procedure for orther
elevator.
RUDDER PULL PULL CABLE
INSTALLATION.
M3lock nut.
See pictures below:
! 1) Insert servo arm into servo.
150mm.
ELEVATOR PUSHROD INSTALLATION.
Repeat the procedure for elevator
pushrod as same as aileron pushrod.
Repeat the procedure for orther
aileron.

www.seagullmodels.com
15
WHEEL AND WHEEL PANTS.
!2) Follow diagram below for wheel pant
installation:
!1) Assembleand mountingthewheelpants
as shown in the following pictures.
WheelCollar.
Axle.
Wheel. Nut.
Wheel Pant.
LandingGear.
Nut.
Plywood Washer.
14mm.
7mm.
!3) You have to trim each axles and using a
tool cutting and cut-off wheel.
Caution when cutting the axles wear
protective goggles.
57mm.
Plywood Washer.

EXTRA 260. Instruction Manual.
16
Landing
gear.
! 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 THEMAIN LANDINGGEAR.
MOUNTING THE ENGINE.
!1) Install the pushrod housing through the
predrilledholein the firewallandinto the servo
compartment. The pushrod housing should
protrude 1/4" out past the front of the firewall.
MakeaZ-Bend 1/4" fromone end oftheplain
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.
6 X 20mm.
140mm.
lite-plywoodblock.

www.seagullmodels.com
17
! 6) AttachtheZ-Bend inthepushrod wireto
thethrottlearmonthecarburetor.Youwillneed
toremovethethrottlearmfromthecar-buretor
to be able to attach the Z-bend. When
complete,re-attach the throttlearm tothe car-
buretor.
! 5) Bolttheenginetotheengine mountusing
the four machine screws. Double check that
all the screws are tight before proceeding.
4.2mm.
4x30mm.
Engine .91 - 2 stroke.
4x30mm.
Pushrod wire.
Engine 1.25 - 4 stroke.
140mm.
COWLING.
!1) Slide the fiberglass cowl over the en-
gineandline up thebackedge of thecowlwith
themarks youmade on the fuselage thentrim
and cut.
Pushrod wire.
3x10mm.
Trim and cut.

EXTRA 260. Instruction Manual.
18
!3) Installthemufflerandmufflerextension
onto the engine and make the cutout in the
cowl for muffler clearance. Connect the fuel
and pressure lines to the carburetor, muffler
and fuel filler valve. Secure the cowl to fuse-
lage using the 3x10mm screws (4).
opening.Usethespinnerbackplateasaguide.
Hold the cowl firmly in place using pieces of
masking tape.
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.
Install the spinner backplate, propeller and
spinner cone.
INSTALLING THE SPINNER.
1.5mm wire
(needlevalve).
!2) While keeping the back edge of the
cowl flush with the marks, align the front of
thecowlwiththecrankshaftoftheengine. The
front of the cowl should be positioned so the
crankshaft is in nearly the middle of the cowl
Because of the size of the cowl, it may be
necessary to use a needle valve extension
for the high speed needle valve. Make this
out of sufficient length 1.5mm wire and install
it into the end of the needle valve. Secure the
wirein placeby tightening the set screw in the
side of the needle valve.
Trim and cut.
3 x 10mm.

www.seagullmodels.com
19
INSTALLING TAIL STRUT SYSTEM.
Tail strut system assembly follow pictures
below.
3x10mm.
3.2mm drill bit.
Turnbuckle.
Horizontal stabilizer.
M3lock nut.
14cm. 8cm.
0cm.

EXTRA 260. Instruction Manual.
20
2
1
33mm.
MOUNTING THE TAIL WHEEL.
! 2) Set the tail wheel assembly in place.
The pivot point of the tail wheel wire should
be even with the rudder hinge line and the tail
wheel bracket should be on the plywood
plate.
! 3) Using a pen, mark the locations of the
four mounting screws. Remove the tail wheel
bracket and tiller and drill 1mm pilot holes at
the locations marked.
3x25mm.
!1) You have to trim each axles and using a
tool cutting and cut-off wheel.
Caution when cutting the axles wear
protective goggles.
3x10mm.
Aluminium strap.
1
2
1
2
1
1
(1+2) Plastic clip.