Seagull Models Extra 300 User manual

Kit features.
• Ready-made—minimalassembly&finishingrequired.
• Ready-coveredcovering.
• Photo-illustratedstep-by-stepAssemblyManual.
MadeinVietnam.
Specifications
WingSpan-------------------------------43in---------------------109cm.
WingArea-------------------------------367sqin----------23.7sqdm.
Weight------------------------------------20-21oz------------566-595g.
Length------------------------------------ 38.4in-------------------97.5cm.
Radio-------------------------------4channelwith4sub-microservos.
Motorsize----------------------------Park450toPark480Outrunner.
Need to Complete
Speed Control: 35A to 40A Brushless
RecommendedBattery3-cell 11.1V 1320mAh to 2100mAh Li-Po.
ASSEMBLY MANUAL

EXTRA 300. Instruction Manual.
2
INTRODUCTION.
Thank you for choosing the EP EXTRA 300 ARTF by SEAGULL EP. The EP EXTRA 300 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 EP EXTRA 300 is simply a joy.
This instruction manual is designed to help you build a great flying aeroplane. Please read this
manualthoroughlybefore startingassemblyof your EP EXTRA 300. Usethe parts listingbelow 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.
!Motor:Park 450 to Park 480
Outrunner.
!Computer radio with four sub-
micro servos ( S75 7.5gram (
EFLRS75)) .
!Propeller 10x4.7 electric.
!Speed control: 35A to 40 A
brushless.
!Battery: 3 cell 11.1 V / 1320 -
2100mAh Li-Po.
Park 480 outrunner 910KV (EFLM1510)
40-Amp Brushless ESC (EFLA312B).
-3Cell.11.1V1320mAh Li-po ( THP1320SPL)
-3Cell, 11.1V1900mAh Li-po (THP19003S).
-3Cell,11.1V2100mAhLi-po(THP21003SPL)

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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.
Tail section assembly
!(1) Horizontal stabilizer/ elevator
halves.
!(1) Rudder halves.
Some more parts.
HARDWAREPACK
COWLING
Landinggear.....
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 EP EXTRA 300 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
onthecovering and the plasticparts.
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.

EXTRA 300. Instruction Manual.
4
!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 wing
panel until the T-pin is snug against the wing
panel. This will help ensure an equal amount
ofhingeison either sideofthehingeline when
the aileron is mounted to the aileron.
HINGING THE AILERONS.
!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 wing panel
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
!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,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
penetrateanddistributethroughout 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.
Hinge.
T-pin.
Hinge.
T-pin.
T-pin.
C/Aglue.
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 placeper the steps that follow
using a high-quality thin C/A glue.
Note:

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Work the aileron up and down several
times to “work in” the hinges and check
for proper movement.
HINGING THE ELEVATORS.
Note:
!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.
!7) Repeat this process with the other wing
panel, securely hinging the aileron in place.
!6)Using C/Aremover/debonderandapaper
towel, remove any excess C/A glue that may
haveaccumulatedonthe wing or intheaileron
hingearea.
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.
C/Aglue.
!1) Assembleand mountingthewheelpants
as shown in the following pictures.
WHEEL AND WHEEL PANTS.
C/Aglue.

EXTRA 300. Instruction Manual.
6
C/Aglue.
C/Aglue.
!1) Usingthe hardware provided, mount the
main landing gear to the fuselage.
INSTALLING THE MAIN LANDING GEAR.
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.
C/Aglue.
3 X 12mm.
INSTALLING ELECTRIC MOTOR.
Park 450 to Park 480

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C/Aglue.
Front view.
COWLING INSTALLATION.
!1) Slide the fiberglass cowl over the en-
gineandline up thebackedge of thecowlwith
themarks youmade on thefuselage thentrim
and cut.
Rotor shaft.
Motor.
Blindnut.
Trim and cut.
3x10mm.

EXTRA 300. Instruction Manual.
8
Because the size of servos differ, you
mayneedtoadjustthe size of the precut open-
ing in the mount. The notch in the sides of
themountallowtheservoleadtopassthrough.
Install the rubber grommets and brass
collets onto the aileron servo. Test fit the
servo into the aileron servo mount.
!1) Install the rubber grommets and brass
eyelets onto the aileron servo.
!2) Install the metal connector onto servo
arm.
!3) Turn the wing panel right side up. Using
amodelingknife,removethecoveringatservo
tray.
!2) While keeping the back edge of the
cowl flush with the marks, align the front of
thecowl withthe crankshaftof the motor. The
front of the cowl should be positioned so the
crankshaft is in nearly the middle of the cowl
opening.Usethespinnerbackplateasa guide.
Hold the cowl firmly in place using pieces of
masking tape.
3x10mm.
!3) Slide the cowl back over the motor.
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.
AILERON SERVOS - LINKAGES.
Servo(2pcs).
Small weight.
Thread.

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Aileroncontrol horn.
Using a small weight (Weighted fuel pick-up
workswell) and thread, feedthestring through
the wing as indicated.
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.Tapethe servo lead to the wing to prevent
it from falling back into the wing.
Secure the servos with the screws pro-
vided with your radio system.
Straigh line.
!4) Using a ruler & pen to draw a straight
line as pictures below
Pen.
!5) Insert aileron control horn to the aileron.
Attach the micro control connector to the
servo arms. Be sure to use the lock tie but it
could free rotation .
Wing bottom.
M2x12mm.

EXTRA 300. Instruction Manual.
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!2) Installthe rubbergrommets and brass
collets onto the elevator servo. Test fit the
servo into the elevator servo mount.
!3)Secure theservos with the screws pro-
vided with your radio system.
Because the size of servos differ, you
mayneedtoadjustthesize of the precut open-
ing in the mount. The notch in the sides of the
mount allow the servo lead to pass through.
INSTALLING THE SWITCH.
Installthe switch intothe precut holein the
side, in the fuselage.
Rightside.
Elevator servo.
Left side.
Rudder servo.
HORIZONTALSTABILIZER.
!1) Using a ruler and a pen, locate the
centerlineof thehorizontalstabilizer,atthe trail-
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.
Remove covering.
Switch.
Center line.
Repeat the procedure for orther wing
haft.
!1) Locateandcut out thecovering film from
the servo holes in both sides of fuselage.
FUSELAGE SERVO INSTALLATION.
Rightside.
Remove
covering.
Repeat the procedure for rudder servo.

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!2)Usinga modeling knife, carefullyremove
thecoveringat mountingslotof horizontal sta-
bilizer ( both side of fuselage).
! 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. ! 7) When you are sure that everything is
alignedcorrectly,apply C/Aglue to the top and
bottom of the stabilizer mounting area and to
the stabilizer mounting platform sides.
! 5) Removethe stabilizer. Using thelines
youjust drewas a guide, carefully removethe
covering from between them using a model-
ingknife.
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.
! 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.
Pen.
Removecovering.
!1) Using a modeling knife, remove the
covering from over the precut hinge slot cut
intothelowerrearportionofthe fuselage. This
slot accepts the lower rudder hinge.
VERTICAL STABILIZER INSTALLATION.
Hinge.
Hingeslot.

EXTRA 300. Instruction Manual.
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!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 enoughpressure to only
cut through the covering itself. Cutting into
the balsa structure may weaken it.
!5) Slide the vertical stabilizer back in
place. Using a triangle, check to ensure that
thevertical stabilizer is aligned 90ºto thehori-
zontal stabilizer.
90º
Vertical
Stabilizer.
Horizontal
Stabilizer.
Pen.
C/Aglue.
!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 bottomedge of the stabi-
lizer should also be firmly pushed against the
top of the horizontal stabilizer.
! 6) When you are sure that everything is
aligned correctly, apply C/Aglue to fix them.
Remove
covering.

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Control horn install as same as method of
aileron wing. See pictures below.
Rudder control horn.
Elevator control horn.
PUSHROD INSTALLATION.
Pushrod install as same as method of
pushrod wing. See pictures below.
Pushrod.
Rudder
servo.
Elevator
servo.
MOUNTING THE TAIL WHEEL BRACKET.
See pictures below:
2x12mm.
CONTROL HORN INSTALLATION.

EXTRA 300. Instruction Manual.
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Insert two wing panels as pictures below:
ATTACHMENT WING-FUSELAGE.
Attach the aluminium tube into fuselage.
INSTALLING THE BATTERY-RECEIVER.
Battery.
Receiver.
See pictures below.
Battery tray
Tie wrap.
M2x8mm.
Tie wrap or rubber band.
Expoyglue.

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BALANCING.
!1) It is critical that your airplane be bal-
anced correctly. Improper balance will cause
yourplaneto lose controland crash. The cen-
ter of gravity is locate 7-8cm back from the
leading edge of the wing, measured at wing
tip.
!2) If the nose of the plane falls, the plane
is nose heavy. To correct this first move the
battery pack further back in the fuselage. If
this is not possible or does not correct it, stick
small amounts of lead weight on the fuselage
! 3) When the elevator, rudder and aileron
control surfaces are centered, use a ruler and
check the amount of the control throw in each
surface. The control throws should be
measured at the widest point of each sur-
face!
sides under the horizontal stabilizer. If the tail
of the plane falls, the plane is tail heavy. To
correctthis,move thebatteryand receiver for-
ward orif this is not possible, stick weight onto
the firewall or use a brass heavy hub spinner
hub, similar to those offered by Harry Higley.
When balanced correctly, the airplane should
sit level or slightly nose down when you lift it
up with your fingers.
!2) Turn onthe radio system, and with the
trim tabs on the transmitter in neutral, center
the control surfaces by making adjustments
totheclevises or adjustable servoconnectors.
The servo arms should be centered also.
CONTROL THROWS.
!1) We highly recommend setting up the
EP EXTRA 300 usingthe control throwslisted
atright. Wehave listedcontrolthrows for both
Low Rate (initial test flying/sport flying) and
High Rate (aerobatic flying).
INITIAL FLYING/SPORT FLYING
Do not use the aerobatic settings for
initial test flying or sport flying.
Ailerons: 5/8” up 1/2” down
Elevator: 3/4” up 3/4” down
Rudder: 2 1/2” right and left
AEROBATIC FLYING
Ailerons: 1” up 7/8” down
Elevator: 1 1/4” up 1 1/4”down
Rudder: 3 1/2” right and left
! 4) By moving the position of the adjust-
able control horn out from the control surface,
you will decrease the amount of throw of that
control surface. Moving the adjustable con-
trol horn toward the control surface will in-
crease the amount of throw.
Wing bolt.
Wing bolt.

EXTRA 300. Instruction Manual.
16
FLIGHT PREPARATION.
! A) Check the operation and direction of
the elevator, rudder, ailerons and throttle.
! B) Plug in your radio system per the
manufacturer's instructions and turn every-
thingon.
! E)Check the throttle.
! D) Check the rudder. Looking from be-
hindthe airplane, move the rudder stick tothe
right. Theruddershould move tothe right. If it
does not, flip the servo reversing switch on
your transmitter to change the direction.
! C) Check the elevator first. Pull back on
theelevator stick. The elevator halves should
move up. If it they do not, flip the servo re-
versing switch on your transmitter to change
the direction.
! F) From behind the airplane, look at the
aileronontheright wing half. Movetheaileron
sticktotheright. Therightaileronshouldmove
upand the otheraileronshould movedown. If
it does not, flip the servo reversing switch on
your transmitter to change the direction.
!5) If your radio transmitter is equipped
withdual rate switchesdouble checkthat they
are on the low rate setting for your first few
flights.
!6) Check to ensure the control surfaces
are moving the proper amount for both low
and high rate settings.
!8) Properlybalance thepropeller. An out
of balance propeller will cause excessive vi-
bration which could lead to engine and/or air-
frame failure.
We wish you many safe and enjoyable
flights with your EP EXTRA 300.
!7) Check the receiver antenna. It should
be fully extended and not coiled up inside the
fuselage.
PREFLIGHT CHECK.
!1) Completely charge your transmitter
and receiver batteries before your first day of
flying.
!2) Check every bolt and every glue joint
in the EP EXTRA 300 to ensure that every-
thing is tight and well bonded.
!3) Double check the balance of the air-
plane. Do this with the fuel tank empty.
!4) Checkthe controlsurfaces. All should
move in the correct direction and not bind in
any way.