Seagull Models SEA274 User manual

1
ASSEMBLY MANUAL
Specications:
Wingspan---------------82.0 in (208.2 cm).
Wing area---------------1349.4 sq.in ( 87.1 sq.dm).
Weight-------------------16.3 -16.8 lbs (7.4- 7.6kg).
Length-------------------77.7 in (197.3 cm).
Engine-------------------50cc-55cc gasoline.
Radio--------------------6 channels with 6 servos.
“ Graphics and specications may change without notice ” .
Code: SEA274
EXTRA 330LX

EXTRA 330LX Instruction Manual.
2
ank you for choosing the EXTRA 330LX ARF by SG MODELS . e EXTRA 330LX
was designed with the intermediate/advanced sport yer in mind. It is a semi scale airplane
which is easy to y and quick to assemble. e airframe is conventionally built using balsa,
plywood to make it stronger than the average ARF, yet the design allows the aeroplane to be
kept light. You will nd that most of the work has been done for you already. e motor mount
has been tted and the hinges are pre-installed. Flying the EXTRA 330LX is simply a joy.
is instruction manual is designed to help you build a great ying aeroplane. Please read
this manual throughly before starting assembly of your EXTRA 330LX . Use the parts listing
below to indentify all parts.
ADDITIONAL ITEMS REQUIRED. TOOLS & SUPPLIES NEEDED.
INTRODUCTION.
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 & REPONSIBILITY.
If you are inexperienced with basic R/C ight we strongly recommend you contact your R/C
supplier and join your local R/C model Flying Club. R/C Model Flying Clubs oer a variety
of training procedures designed to help the new pilot on his way to successful R/C ight.
ey will also be able to advise on any insurance and safety regulations that may apply.
in cyanoacrylate glue.
Medium cyanoacrylate glue.
30 minute epoxy.
5 minute epoxy.
Hand or electric drill.
Assorted drill bits.
Modelling knife.
Straight edge ruler.
2mm ball driver.
Phillips head screwdriver.
220 grit sandpaper.
90° square or builder’s triangle.
Wire cutters.
Masking tape & T-pins.
read-lock.
Paper towels.
�50cc-55cc gasoline engine.
�Computer radio with 6 servos.
�Glow plug to suit engine.
�Propeller to suit engine.
�Protective foam rubber for radio
system.

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EXTRA 330LX Instruction Manual.
4
INSTALL THE AILERONS
CONTROL HORN.
Epoxy.
Epoxy.
Aileron control horn.
INSTALLING THE AILERON SERVOS.
1) e ailerons have been pre-hinged
and glued to the wing panels and are
ready for ight. No other steps are neces-
sary for hinging.
2) Layout the servo on the wing to test t
the installation and ensure servo lead is
the correct length.
3) Attach the extension to the servo lead
and secure with Safety Clip, safety wire,
tape or other method. Ensure the plugs
will not come apart from vibration or
light tension.
4) Fasten the pull string from the servo
hole to the male plug of the servo exten-
sion.
Fiberglass control horn
NOTE : servos arm for aileron is not pro-
vided from manufacturer.

5
5) Install servo in servo well with the out-
put arm toward the leading edge of the
wing. Mark and drill location of servo
mounting holes.
6) Install servo with servo mounting
screws.
in CA.
38mm
INSTALLING THE AILERON
PUSHROD.
M3x15 Socket Head Cap Screw.
Flat washer.
Lock nut.
M3x15 Socket Head Cap Screw.
Lock nut.
Flat washer.

EXTRA 330LX Instruction Manual.
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ELEVATOR SERVO INSTALLATION.
1) e elevators have been pre-hinged
and glued to the stabs and are ready for
ight. No other steps are necessary for
hinging.
INSTALL ELEVATOR CONTROL HORN.
Elevator berglass control horn.
Epoxy.
Epoxy.
Fiberglass control horn
2) Attach the extension to the servo lead
and secure with Safety Clip, safety wire,
tape or other method. Ensure the plugs
will not come apart from vibration or
light tension.
Repeat all the above steps for the other
wing.
100mm
NOTE : servos arm for elevator is not pro-
vided from manufacturer.

7
3) Feed servo extension through the el-
evator servo mounting hole.
4) Mark and drill location of servo
mounting holes.
in CA.
38mm
5) Install servo with servo mounting
screws.
ELEVATOR PUSHROD INSTALLATION.
M3x15 Socket Head Cap Screw.
Flat washer.
Lock nut.

EXTRA 330LX Instruction Manual.
8
.
.
INSTALL RUDDER CONTROL HORN.
Repeat all the above steps for the other
elevator.
M3x15 Socket Head Cap Screw.
Lock nut.
Flat washer.
Fiberglass control horn
38mm
Epoxy.
Use scotch tape to avoid
pushrod drop out.

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1) Gather one rudder ervo, mounting
screws, servo arm and the rudder control
linkage parts shown below.
INSTALL RUDDER CABLE AND SERVO.
38mm
2) Tape the rudder balance tab to the top
leading edge of the vertical n in the neu-
tral position as shown. is ensures the
rudder is straight when the cables are at-
tached.
3) read the rudder cable through a
brass swage tube, then the threaded cou-
pler, and back through the brass swage
tube on both sides. Pull light tension on
the cable through the coupler on both
sides as shown.
M3x15 Socket Head Cap Screw.
Lock nut.
Flat washer.
5) Crimp the brass tube with a crimping
tool or pliers.
4) Loop the cable back through the brass
swage tube and tighten the second loop
through the brass swage tube as shown.
NOTE : servos arm is not provided from
manufacturer.

EXTRA 330LX Instruction Manual.
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11) Loop the cable back through the brass
swage tube and pull tight.
10) read cable through the threaded
coupler hole, and back through the brass
swage tube as shown.
6) Cut o excess cable as shown.
7) Mark and use a 1/16 bit to drill the
rudder servo.
9) read cable through brass swage tube.
8) Feed one rudder cable through the pre
installed cable exit tube in the rear of the
fuse toward the front of the fuse. Repeat
for other side.
in CA.

11
12) Crimp the brass swage tube with a
crimping tool or pliers.
14) Attach ball links to the rudder servo
arm and then attach the servo arm to the
rudder servo as shown.
NOTE : Cable is installed crossed “ X”, not
parallel.
13) Cut o excess cable as shown.
15) Attach the aluminum tube to com-
bine two elevator as below pictures.

EXTRA 330LX Instruction Manual.
12
TAILWHEEL INSTALLATION.
Locate items necessary to install tail-
wheel.
Place a drop of Blue Loctite on tail wheel
strut mounting screws.
M4x15 Socket Head Cap Screw.
Washer. Fuel Tubing.
M3x15mm
Blue Loctite.

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Attach the steering spring to the rudder
control horn.
Use pliers to twist spring end closed
around rudder control horn.
Do same for attachment the steering
spring to the rudder tiller.
Repeat spring installation for other side.
INSTALLING THE MAIN LANDING
GEAR TO FUSELAGE.
1) e blind nuts for securing the land-
ing gear are already mounted inside the
fuselage.
2) Using the hardware provided, mount
the main landing gear to the fuselage.
3) Place the fuselage inverted on the
workbench in a suitable stand. Set the
landing gear in place and use a screw-
drive to secure the landing gear to the fu-
selage using bolts M4x25mm and wash-
ers. Make sure to use the threadlock on
the bolts so they don’t vibrate loose.

EXTRA 330LX Instruction Manual.
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M4x25mm
Washer.
Use lock nut to secure landing gear
tighen into fuselage.
Install gear cover into landing gear.
3x10mm

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Using locknut install axle to gear.
Align the wheel pant slot over the axle
bolt as shown. Slide the wheel pant slot
over the at sides of the axle bolt and align
blind nuts in wheel pants with mounting
holes in landing gear. When all bolt holes
are aligned tighten axle in place.
in CA.
3x10mm
M3x4mm

EXTRA 330LX Instruction Manual.
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Install the wheel and outer wheel collar.
Use blue Loctite on the wheel collar set
screw before nal tightening
Use blue Loctite on the bolts before nal
tightening.
M3x4mm
M3x10mm
Washer.
Align mounting template to front of
rewall.
Locate the laser cut engine mounting
template.
MOUNTING THE ENGINE.
NOTE : It’s the canister mount which is
used to assemble the canister exhaust sys-
tem. It’s only for extra reference purpose
for your model.

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Use a 1/4 bit to drill the engine mount-
ing holes
Remove mounting template from re-
wall. Firewall shown with mounting holes
drilled ready for engine mounting.
Using mounting bolts and washers
mount engine to rewall.
Tighten mounting bolts and secure en-
gine to rewall.
1) Use a 1/4” bit to drill a pushrod exit
hole in the rewall in line with the en-
gine carburetor throttle arm.
2) Assemble ball link to threaded end of
pushrod.
THROTTLE SERVO INSTALLATION.

EXTRA 330LX Instruction Manual.
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3) Attach throttle pushrod to the carbu-
retor throttle arm with the ball link.
4) Install adjustable servo connector in
the servo arm as same as picture below:
5) Install throttle servo into servo mount-
ing tray.
Servo arm.
Adjustable servo
connector.
Loctite secure.
in CA.
6) Reinstall the servo horn by sliding the
connector over the pushrod wire. Center
the throttle stick and trim and install the
servo horn perpendicular to the servo
center line.
Epoxy.

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1) Position the ignition module on the
side of the engine mounting box and
mark the location of the nylon tie holes
as shown.
2) Use a 1/8” bit to drill the ignition mod-
ule mounting holes.
7) Move the throttle stick to the closed po-
sition and move the carburetor to closed.
Use a 2.5mm hex wrench to tighten the
screw that secures the throttle pushrod
wire. Make sure to use threadlock on the
screw so it does not vibrate loose.
IGNITION INSTALLATION.
3) read nylon tie through mounting
holes.
4) Connect ignition module to pickup
line of engine. Secure with Safety Clip,
safety wire, tape or other method. Ensure
the plugs will not come apart from vibra-
tion or light tension.
5) Secure ignition wire with nylon ties as
necessary.

EXTRA 330LX Instruction Manual.
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Trim and cut.
INSTALLING THE RECEIVER SWITCH.
Install the switch into the precut hole in
the side, in the fuselage.
3/32” Hole.
.
Switch.
Switch.
INSTALLING THE ENGINE SWITCH.
Trim and cut.
FUEL TANK ASSEMBLY.
Please see below pictures.