Seagull Models ZERO MS:123 User manual

“Graphics a nd s pecifications m ay c hange w ithout n otice”.
MS:123
ASSEMBLY MANUAL
Specifications:
Wing span ----------------------------66.9in (170cm).
Wing area -----------------761.1sq.in (49.1sq dm).
Weight -------------------------------------9.3lbs (4.2kg).
Length ------------------------------51.1in (129.8cm).
Engine ------------------ 0.75-0.91cu.in ----2-stroke.
0.91-1.25cu.in ---4-stroke.
Radio -------------------6 channels with 8 servos.
Retracts landing gear (included).
Electric conversion: optional
SIZE .75 - .91

ZERO. Instruction Manual.
2
INTRODUCTION.
Thank you for choosing the ZERO ARTF by SEAGULL MODELS. The ZERO was designed with
the intermediate/advanced sport flyer in mind. It is a semi scale 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 will find that most of the
work has been done for you already.The motor mount has been fitted and the hinges are pre-installed
. Flying the ZERO 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 ZERO . 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 supplier
and join your local R/C Model Flying Club. R/C Model Flying Clubs offer a variety of training
procedures designed to help the new pilot on his way to successful R/C flight. They will also be able
to advise on any insurance and safety regulations that may apply.
KIT CONTENTS
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2
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3
4
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6
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10
4
10
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ADDITIONAL ITEMS REQUIRED.
0.75-0.91 2-stroke.
0.91-1.25 4-stroke.
Computer radio with 8 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.
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.
Thread-lock.
Paper towels.
The control surfaces, including the
ailerons, elevators, and rudder, are
prehinged with hinges installed, but
the hinges are not glued in place. It
is imperative that you properly
adhere the hinges in place per the
steps that follow using a high-quality
thin C/A glue.
2) Remove each hinge from the wing panel
and aileron and place a T-pin in the center of
each hinge. Slide each hinge into the aileron
until the T-pin is snug against the aileron. This
will help ensure an equal amount of hinge is
on either side of the hinge line when the aileron
is mounted to the wing panel.
HINGING THE AILERONS .
Note:
1) Carefully remove the aileron from one
of the wing panels. Note the position of the
hinges.
Hinge.
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 a nd snug the aileron
against the wing panel. A gap of 1/64” or less
should be maintained between the wing panel
and aileron.
T-pin.
1 Fuselage
2 Left wing panel
3 Right w ing p anel
4 Tail s et ( 2)
5 Canopy
6 Aluminum wing tube
7 Fiberglass cowl
8 Retracts landing gear
9 EP conversion pack
10 Hardware bag included
11 Retract covers
KIT CONTEN.TS

ZERO. Instruction Manual.
4
INSTALL THE AILERONS CONTROL
HORN.
1) Locate the hardware necessary to install
the control horns for the ailerons.
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/A remover/debonder and a
paper towel, remove any excess C/A glue that
may have accumulated on the wing or in the
aileron hinge area.
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, making sure that the C/A penetrates into
both the aileron and wing panel.
Work the aileron up and down several
times t o “ work i n” t he h inges a nd
check for proper movement.
Note:
4) Deflect the aileron and completely
saturate each hinge with thin C/A glue. The
ailerons front surface should 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.
The hinge is constructed of a special
material that allows the C/A to wick
or penetrate and distribute
throughout the hinge, securely
bonding it to the wood structure of
the wing panel and aileron.
Note:
Hinge.

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Aileron control horn.
2) Position the control horn on the bottom of
the aileron. You will see pre-drill hole 3mm for
the horn mounting screw on the aileron.
3) Place epoxy into hole. This will harden the
threads and prevent the crews from pulling
loose.
4) Thread a control horn end with aluminum
washer, lock nut until the top edge of the end is
9mm from the v ase of the horn as shown.
3mm.
Install the flap control horn using the same
method as same as the aileron control horns.
INSTALL FLAP CONTROL HORN.
2 sets.
3x35mm.
2 sets.
3x35mm.

ZERO. Instruction Manual.
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3mm.
Flap control horn.
Install the elevator control horn using the
same method as same as the aileron control
horns.
INSTALL ELEVATOR CONTROL HORN.
Hinge.
C/A glue.
C/A glue.
Hinge.
T-pin. 2 sets.
3x35mm.

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Elevator control horn.
ENGINE MOUNT INSTALLATION.
1) Locate the items necessary to install the
engine mount included with your model. .
2) Use four 4x30mm head bolts and four 4mm
washers to attach the engine mount rails to
the firewall. Tighten the screws . Make sure to
use threadlock on the screws to help prevent
them from vibrating loose.
4x30mm.
C/A glue.
Balsa.
Thread locker glue.
Balsa.
Epoxy.
Epoxy.
C/A glue.

ZERO. Instruction Manual.
8
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.
3) Carefully bend the second nylon tube
up at a 45º angle. This tube is the vent tube.
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.
Vent tube. Fuel pick up tube.
Fuel fill tube.
5) With the stopper assembly in place,
the weighted pick-up should rest away from
the rear of the tank and move freely inside the
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
the stopper assembly tighten the 3 x 20mm
machine s crew u ntil t he r ubber s topper e x-
pands and seals the tank opening. Do not
overtighten the assembly as this could cause
the tank to split.
FUEL TANK INSTALLATION.
 7) Slide the fuel tank into the fuselage. Guide
the lines from the tank through the hole in the
firewall.
Plywood template.
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.
INSTALLING THE STOPPER ASSEMBLY.
2) Using a modeling knife, cut one length
of silicon fuel line. Connect one end of the line
to the weighted fuel pick up and the other end
to the nylon pick up tube.

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Fuel tank.
Epoxy.
Fuel tank.
 8) Use plywood template to hold in place
the fuel tank with C/A glue to secure the fuel
tank i nside t he f uselage.
Plywood template.
Blow through one of the lines to en-
sure the fuel lines have not become kinked
inside the fuel tank compartment. Air
should flow through easily.
9) Connect the lines from the tank to the engine
and muf fler. The vent line will connect to the
muffler and the line from the clunk to the
carburetor.
INSTALLING THE FUSELAGE SER VOS.
1) Install the rubber grommets and brass
collets onto the throttle servo. Test fit the servo
into the aileron servo mount.
 2) Secure the servos with the screws pro-
vided with your radio system.
Because the size of servos differ, you
may need to adjust the size of the precut open-
ing in the mount. The notch in the sides of the
mount allow the servo lead to pass through.
Vent tube.
Fuel pick up tube.
Fuel fill tube.
Throttle servo.
Elevator servo.
Rudder servo.

ZERO. Instruction Manual.
10
Switch.
Trim and cut.
150mm.
MOUNTING THE ENGINE.
 1) Position the engine with the drive washer
(150mm) forward of the firewall as shown.
THROTTLE SERVO ARM INSTALLATION.
Install adjustable servo connector in the servo
arm as same as picture below:
Adjustable Servo
connector.
Servo arm.
Loctite secure.
1 PCS.
Throttle servo arm.
Elevator servo arm.
Rudder servo arm.
3/ 32” Hole.
INSTALLING THE SWITCH.
Install the switch into the precut hole in the
side, in the fuselage.
SERVO GEAR INSTALLATION.
Servo for retractable only.
Metal connector.
Servo arm.
25mm.
Throttle servo arm.
Elevator servo arm.
Rudder servo arm.
Stearing servo arm.

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Machine screw M4x30mm.
Pushrod wire.
2) Use a pin drill and 4mm drill bit to drill a
small i ndentation i n t he mo unt f or t he e ngine
mounting screw.
3) Use a drill to drill the four holes in the engine
mount rails.
4) On the fire wall has the location for the
throttle pusshrod tube (pre-drill).
7) Slide the throttle pushrod wire into the tube.
Position the engine between the mounts. Use
four M4x30mm machine screws to secure the
engine to the mount as shown.
5) Slide the pushrod tube in the firewall and
guide it through the fuel tank mount. Use
medium C/A to glue the tube to the firewall and
the fuel tank mount.
6) Connect the Z-bend in the 450mm throttle
pushrod to the outer hole of the carburetor arm.
4.5mm.
Pushrod tube hole.
4mm.
8) 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 s ervo center line.
9) Move the throttle stick to the closed position
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.

ZERO. Instruction Manual.
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150mm.
2) Use a pin drill and 4mm drill bit to drill a
small i ndentation i n t he mo unt f or t he e ngine
mounting screw.
 1) Position the engine with the drive washer
(150mm) forward of the firewall as shown.
4mm.
+ 0.91 - 1.25 : 4 STROKE.
Machine screw M4x30mm.
3) Use a drill to drill the four holes in the engine
mount rails.
4) On the fire wall has the location for the
throttle pusshrod tube (pre-drill).
7) Slide the throttle pushrod wire into the tube.
Position the engine between the mounts. Use
four M4x30mm machine screws to secure the
engine to the mount as shown.
5) Slide the pushrod tube in the firewall and
guide it through the fuel tank mount. Use
medium C/A to glue the tube to the firewall and
the fuel tank mount.
6) Connect the Z-bend in the 450mm throttle
pushrod to the outer hole of the carburetor arm.
4.5mm.
Pushrod tube hole.
Pushrod wire.

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INSTALLING THE BATTERY.
Battery.
8) 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 t he servo center line.
9) Move the throttle stick to the closed position
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.
Battery.
Tie wrap.
Trim and cut.
COWLING.
Trim and cut.
1) Slide the fiberglass cowl over the en-
gine and line up the back edge of the cowl with
the marks you made on the fuselage then trim
and cut as shown.

ZERO. Instruction Manual.
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Because of the size of the cowl, it may be nec-
essary to use a needle valve extension for the
high speed needle valve. Make this out of suf-
ficient length 1.5mm wire and install it into the
end of the needle valve. Secure the wire in
place by tightening the set screw in the side of
the needle valve.
Machine screw M3x10mm.
Needle valve.
 3) Install the muffler and muffler extension
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 M3x10mm screws.
2) While k eeping t he b ack e dge o f t he
cowl flush with the marks, align the front of
the cowl with the crankshaft of the engine. The
front of the cowl should be positioned so the
crankshaft is in nearly the middle of the cowl
opening. Use the spinner backplate as a guide.
Hold the cowl firmly in place using pieces of
masking tape.
ELECTRIC POWER CONVERSION.
1) Locate the items neccessary to install the
electric power conversion included with your
model.
Needle valve.
Trim and cut.
2) Attach the electric mo tor box to the fi rewall
suitable with the cross lines drawn on the electric
motor box and firewall. Using epoxy and balsa
stick to secure the motor box to the firewall.
Please see pictures below.
- Model size: .75-.90 size mo dels
- Motor: 50mm 310 rev per volt
- P ropeller: 1 4x10 ~ 1 5x10
- ESC: 60A
- Lipo Batteries: 8 cell 3200mA

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3mm.
5.2mm.
5.2mm.
Blind nut.
Epoxy.
Epoxy.

ZERO. Instruction Manual.
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3) Attach the motor to the front of the electric
motor b ox u sing f our 4 mm b lind n ut, f our
M4x15mm hex head bolt s to secure the motor .
Please see picture shown.
Epoxy.
150mm.
M4 x 15mm.
Electric motor.
Battery.
4) Locate the plywood battery tray to the
fuselage. Tighten the screws using machine
screws M3x15mm to secure the tray in position.
Speed control.
5) Attach the speed control to the side of the
motor box using two-sided tape and tie wraps.
Connect the appropriate leads from the speed
control to the motor. Make sure the leads will
not inte rfere with the opera tion of the motor .
INSTALLING THE SPINNER.
Install the spinner backplate, propeller and
spinner cone.
Epoxy.
M3x15mm.
Balsa.
Epoxy.
C/A glue.

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INSTALLING THE AILERON - FLAP SERVOS.
Servos. Small weight.
Thread.
1) Using a small weight (Weighted fuel pick-up
works well) and string, feed the string through
the wing as indicated.
Because the size of servos differ, you
may need to adjust the size of the precut open-
ing in the mount. The notch in the sides of
the mount allow the servo lead to pass through.
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.
String.
Small weight.
3) Use drill bit in a pin vise to drill the mouting
holes in the blocks.
2) Place the servo between the mounting
blocks and space it from the hatch. Use a pencil
to m ark t he m ounting h ole l ocations o n t he
blocks.
5) Use dental floss to secure the connection
so they cannot become unplugged.
4) Apply 2-3 drops of thin C/A to each of the
mounting holes. Allow the C/A to cure without
using accelerator.

ZERO. Instruction Manual.
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6) Secure the servo to the aileron hatch using
Phillips screwdriver and the screws provided
with the servo.
7) Apply 1-2 drops of thin C/A to each of the
mounting tabs. Allow the C/A to cure without
using accelerator.
C/A glue.

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8) A string has been provided in the wing to
pull the aileron lead through to the wing root.
Remove the string from the wing at the servo
location and use the tape to attach it to the
servo extension lead. Pull the lead through the
wing and remove the string.
M2x12mm.
M2x12mm.
Attach the string to the servo lead and
carefully thread it though the wing.
Flap servo.
Aileron servo.
Wing rib.
Small weight.
String.
Flap servo.
Aileron servo.

ZERO. Instruction Manual.
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Repeat the procedure for the other aileron servo.
Wing.
Aileron.
M2 lock nut.
Snap keeper.
Servo arm.
3) Connect the linkage as shown and secure
the control wire with a snap keeper.
8mm
Snap keeper.
M2 lock nut. Metal clevis.
1) Mark the control wire where it crosses the
servo arm hole.
Bend at t he m ark.
2) Make a 90-degree bend at the mark and cut
off the excess wire leaving 8mm past the bend.
Cut.
8mm.
AILERON PUSHROD HORN INSTALLATION
Mark.
Pen.