“Graphics and specifications may change without notice”.
ASSEMBLY MANUAL
MS: 131
Specifications:
Wing span ---------------------------68.9in (175cm).
Wing area ---------------1026.1sq.in (66.2sq dm).
Weight --------------------11.5-14.3lbs (5.2-6.5kg).
Length ------------------------------64.8in (164.7cm).
Engine -----------------1.2 - 1.6 cu.in -----2-stroke.
30-35 --- gasoline engine.
Radio ----------- 6 channels with 6 digital servos.
YAK 55. Instruction Manual
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INTRODUCTION.
Thank you for choosing the YAK 55 ARTF by SEAGULL MODELS. The YAK 55 was designed
with the intermediate/advanced sport scale 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 preinstalled . Flying the YAK 55 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 YAK 55. 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
1
2
3
4
5
5
8
6
7
9
5
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ADDITIONAL ITEMS REQUIRED.
1.2-1.6 cu.in 2-stroke
30-35 gasoline engine.
Radio System required 6 channels
with 6 digital 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
KIT CONTENTS
1 Fuselage
2 Left wing panel
3 Right wing panel
4 Canopy
5 Tail set
6 Aluminum wing tube
7 Scale pilot
8 Main landing gear
9 Fiberglass cowl
1) Sand each end of hinge point hinge
using coarse sandpaper . This will improve the
bond of the epoxy to the hinge. Apply a thin
coat of Petroleum jelly to the hinge point to
prevent the epoxy from gluing the hinge
surface.
3) Allow the glue to fully cure for at least 6
hours.When cured, work each hinge
throughout its full motion several times.This
will break free any epoxy that may have found
its way into the hinge joint. Move the hinge
throughout its full travel until no resistance is
felt. This may take as many as 40 - 45 times.
2) Mix minute epoxy. Using a glue syringe
or toothpick, place 30-minute epoxy into one
of the hinge pockets in the aileron leading edge
of the aileron. Some epoxy should ooze out of
the pocket as the hinge is installed. If not,
remove the hinge and apply more epoxy . Wipe
away any excess epoxy with rubbing alcohol.
Continue installing hinges in the leading edge
of the aileron. The control surfaces (aileron)
will be installed after the epoxy is fully cured.
HINGING THE AILERONS.
Properly hinging the control surfaces on
this models is very important.Poorly
installed hinges affect the model’s
precision and control response and can
also be dangerous.
Note:
C/A glue.
Epoxy.
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HINGING THE ELEVATOR.
HINGING THE RUDDER.
Glue the elevator hinges in place using the
same techniques used to hinge the ailerons.
Glue the rudder hinges in place using the
same techniques used to hinge the ailerons.
Work the aileron up and down several
times to “work in” the hinges and check
for proper movement.
Note:
4) Mix 30 minute epoxy or use Pace PT -
55 hinge glue. Place a sufficient amount of glue
in each of the hinge pockets in one wing panel.
5) Press the aileron and wing together such
that less than a 1/64” hinge line gap exists
between the aileron and wing. The bevels
should virtually touch. Use a paper towel and
rubbing alcohol to wipe away any visible epoxy
around the hinges.
6) Allow the glue to fully cure for at least 6
hours.
7) When fully cured, move each control
surface throughout is travel range serveral
times to break away any epoxy in the hinge.
Be sure to deflect the surface fully.
Epoxy.
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INSTALL AILERON CONTROL HORN.
Aileron control horn.
INSTALL ELEVATOR CONTROL HORN.
Epoxy.
Elevator control horn.
Epoxy .
Epoxy.
INSTALL RUDDER CONTROL HORN.
Epoxy.
Fiberglass control horn.
Fiberglass control horn.
Fiberglass control horn.
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Rudder control horn.
1) Locate the items necessary to install the
engine mount included with your model. .
ENGINE MOUNT INSTALLATION.
4x30mm.
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.
Thread locker glue.
3) Carefully bend the second nylon tube
up at a 45º angle. This tube is the vent tube.
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.
INST ALLING THE STOPPER ASSEMBL Y.
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.(The silicon tube is
not included).
Epoxy.
Epoxy.
A
B
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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 screw until the rubber stopper expands and seals the tank opening. Do not
overtighten the assembly as this could cause
the tank to split.
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.
Important: When the stopper assembly is in-
stalled 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.
Carefully use a lighter or heat gun to
permenently set the angle of the vent tube.
Vent tube.
Fuel pick up tube.
Fuel fill tube.
FUEL TANK INSTALLATION.
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.
Fuel tank.
C/A glue.
Balsa wood included.
8) Use balsa stick to help prevent moveable
from transferring to the fuel tank.
7) Slide the fuel tank into the fuselage.
Guide the lines from the tank through the hole
in the firewall.
C/A glue.
A
Fuel tank.
B
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Fuel pick-up tube.
Fuel fill tube.
Vent tube.
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 .
9) Connect the lines from the tank to the
engine and muffler. The vent line will connect
to the muffler and the line from the clunk to the
carburetor.
Pushrod wire.
1) Locate the items neccessary to install
the wheel and wheel pants as shown.
WHEEL AND WHEEL PANTS
INSTALLATION.
Repeat steps as above to attach remaining wheel pants to the landing gear.
2) You have to trim each axle using a tool
cutting and cut-off wheel.
Caution when cutting the axles and
wear protective goggles.
Aluminum landing gear
.
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INSTALLING THE MAIN ALUMINUM
LANDING GEAR TO FUSELAGE.
Locker glue.
.
M4x 20mm.
3) The blind nuts for securing the landing
gear are already mounted inside the fuselage.
4) Using the hardware provided, mount
the main landing gear to the fuselage.
5) Place the fuselage inverted on the workbench in a suitable stand. Set the landing gear
in place and use a screwdrive to secure the
landing gear to the fuselage using bolts
M4x20mm and washers. Make sure to use the
threadlock on the bolts so they don’t vibrate
loose.
FUSELAGE SERVO INSTALLATION.
We recommended to use long servos arm
(70mm diameter)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
collets onto the servo. Test fit the servo into
the servo mount.
1) Using a small weight (Weighted fuel pick-up
works well) and string, feed the string through
the wing as indicated.
String.
Small weight.
2) Place the servo between the mounting
blocks and space it from the hatch. Use a pencil
to mark the mounting hole locations on the
blocks.
3) Use drill bit in a pin vise to drill the mouting
holes in the 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.
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.
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.
1) Elevator servos: Install the servos in the
both side of fuselage.
Drill a 1mm pilot hole before installing the
screw. Using the screws included with the
servos, fasten the servos in place.
Left side.
Elevator servo.
Right side.
Elevator servo.
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Install the switch into the precut hole in the
side of fuselage.
INSTALLING THE SWITCH.
Switch.
MOUNTING THE ENGINE.
150mm.
1) Position the engine with the drive washer
(150mm) forward of the firewall as shown.
5.2mm diameter.
4) On the fire wall has the location for the
throttle pusshrod tube (pre-drill).
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 600mm throttle
pushrod to the outer hole of the carburetor arm.
2) Use a pin drill and 4mm drill bit to drill a
small indentation in the mount for the engine
mounting screw.
3) Use a drill to drill the four holes in the engine
mount rails.
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Machine M5x30mm Screw
Pushrod wire.
7) Slide the throttle pushrod wire into the tube.
Position the engine between the mounts. Use
four M5x30mm machine screws to secure the
engine to the mount as shown.
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 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.
COWLING INST ALLA TION.
1) Slide the fiberglass cowl over the
engine and line up the back edge of the cowl
with the marks you made on the fuselage then
trim and cut as shown.
Epoxy.
Cut.
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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 wire in
place by tightening the set screw in the side of
the needle valve.
Trim and cut.
Trim and cut.
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 fuselage using the 3x10mm screws to tighten the
screws.
2) While keeping the back edge of the
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.
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SPINNER INSTALLATION.
Install the spinner backplate, propeller and
spinner cone.
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.
1) Using a small weight (Weighted fuel pick-up
works well) and string, feed the string through
the wing as indicated.
Servos.
Small weight.
Thread.
INST ALLING THE AILERON.
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.
Wing bottom.
String.
Small weight.
Attach the string to the servo lead and
carefully thread it though the wing. Once you
have string the lead throught the wing, remove
the string so it can use for the other servo
lead. T ape the servo lead to the wing to prevent
it from falling back into the wing.
Electric wire.
String.
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Repeat the procedure for orther wing.
Secure the servos with the screws
provided with your radio system.
Plastic tape.
Aileron electric.
Wing bottom.
Servo 1.
AILERON PUSHROD HORN INST ALLA TION
M3x30mm.
Repeat the procedure for the other
aileron pushrod.
Wing.
M3 lock nut.
Aileron.
INSTALLING HORIZONTAL FIN.
1) Remove the covering at the rear tail
root of horizontal fin as picture shown below.
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2)Sand the aluminium tube using
sandpaper. This will improve the bond of the
epoxy to the cardboard horizontal fin.
Coat both sides of one half of the aluminium
tube with 30 minute epoxy. Next, pour some
epoxy into the cardboard horizontal fin. Use
enough epoxy to fill any gaps.
3) Insert aluminium tube into the cardboard
of fuselage.
4) Slide the two horizontal fin halves
together and carefully align them at the
possition on the fuselage. Wipe away any
excess epoxy using paper towels.
5) Bolt the horizontal fin to the fuselage
using the 4 machine screws (3x15mm).
Double cheek that all the screws are tight
before proceeding.
INSTALLING THE RUDDER.
1) Remove the covering of vertical fin as
same as picture below.
2) Mix 30 minute epoxy or use Pace PT-
55 hinge glue. Place a sufficient amount of glue
in each of the hinge pockets in vertical fin.
3) Press the rudder and vertical fin together
such that less than a 1/64” hinge line gap exists
between the rudder and vertical fin. The bevels
should virtually touch. Use a paper towel and
rubbing alcohol to wipe away any visible epoxy
around the hinges.
Remove covering.
Machine screw
(3x15mm).
Machine screw
(3x15mm).
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4) Allow the glue to fully cure for at least 6
hours.
5) When fully cured, move each control
surface throughout is travel range serveral
times to break away any epoxy in the hinge.
Be sure to deflect the surface fully.
ELEVATOR - RUDDER CONTROL HORN
INSTALLATION.
Elevator control horn.
1) Install the elevator control horn using
the same method as with the aileron control
horns.
2) Position the elevator control horn on
the both side of elevator.
Rudder control horn.
Elevator control horn.
Rudder control horn.
RUDDER PULL PULL CABLE
INSTALLATION.
M3 lock nut.
See pictures below:
1) Prepair the rudder servo arm by attach
four ball link as same as picture shown below.
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MOUNTING THE TAIL WHEEL.
See pictures below.
Cut.
Elevator pushrod.
Control horn.
Metal clevis.
Rudder pushrod.
M2 lock nut.
Rudder pushrod.
2) Insert servo arm into servo.
Rudder servo arm.
ELEVATOR PUSHROD INSTALLATION.
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INSTALLATION PILOT.
1) A scale pilot is included with this ARF. The
Seagull Pilot included fitting well to the cockpit.
(or you can order others scale pilot figures
made by Seagull factory. They are available at
Seagull distributors.)
If you are going to install a pilot figure, please
use a sanding bar to sand the base of the figure
so that it is flat.
2) Position the pilot figure on the canopy floor
as show. Locate the oval shaped on the canopy
floor and remove the covering. Use epoxy to
glue this into the base of the pilot figure, please
see pictures as shown.
Epoxy.
- Apply a bead of canopy glue around the inside
edge of the canopy. Position the canopy onto
the hatch. Use tape to hold the canopy secure
until the glue fully cures.
3) Position the canopy onto the fuselage. Trace
around the canopy and onto the fuselage using
a felt-tipped pen.
1
2
3
2
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Wing bolt.
Insert two wing panels as pictures below.
Wing tube.
Attach the aluminium tube into fuselage.
ATTACHMENT WING - FUSELAGE.
INSTALLING THE BATTERY-RECEIVER.
Receiver.
1) Plug the five servo leads and the switch
lead into the receiver. Plug the battery pack
lead into the switch also.
2) Wrap the receiver and battery pack in
the protective foam rubber to protect them
from vibration.
3) Route the antenna in the antenna tube
inside the fuselage and secure it to the bottom of fuselage using a plastic tape.
APPLY THE DECALS.
1) If all the decals are precut and ready to
stick. Please be certain the model is clean and
free from oily fingerprints and dust. Position
decal on the model where desired, using the
photos on the box and aid in their location.
2) If all the decals are not precut, please use
scissors or a sharp hobby knife to cut the
decals from the sheet. Please be certain the
model is clean and free from oily fingerprints
and dust. Position decal on the model where
desired, using the photos on the box and aid
in their location.
M2 x 6mm.
C/A glue.
4) Install the canopy and secure it with M2x6mm
screws.
1
3
Battery.
2mm.
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BALANCING.
3) Turn the airplane upside down. Place
your fingers on the masking tape and carefully
lift the plane .
2) Mount the wing to the fuselage. Using
a couple of pieces of masking tape, place
them on the top side of the wing
130 mm
back from the leading edge of the wing at the
wing root.
1) It is critical that your airplane be
balanced correctly. Improper balance will
cause your plane to lose control and crash.
THE CENTER OF GRA VITY IS LOCATED
130 MM BACK FROM THE LEADING EDGE
OF THE WING AT THE WING ROOT.
M3x15mm.
With the wing attached to the fuselage, all
parts of the model installed ( ready to fly), and
empty fuel tanks, hold the model at the
marked balance point with the stabilizer level.
Lift the model. If the tail drops when you lift,
the model is “tail heavy” and you must add
weight* to the nose. If the nose drops, it is
“nose heavy” and you must add weight* to the
tail to balance.
Accurately mark the balance point on the top
of the wing on both sides of the fuselage. The
balance point is located
130 mm back from
the leading edge of the wing at the wing root.
This is the balance point at which your model
should balance for your first flights. Later , you
may wish to experiment by shifting the balance
up to 10mm forward or back to change the
flying characteristics. Moving the balance
forward may improve the smoothness and
arrow- like tracking, but it may then require
more speed for take off and make it more
difficult to slow down for landing. Moving the
balance aft makes the model more agile with
a lighter and snappier ”feel”. In any case,please
start at the location we recommend .
*If possible, first attempt to balance the model
by changing the position of the receiver battery
and receiver. If you are unable to obt ain good
balance by doing so, then it will be necessary
to add weight to the nose or tail to achieve the
proper balance point.
130mm.
CONTROL THROWS.
Ailerons: 10mm low rate 12mm high rate.
Elevator: 10mm low rate 12mm high rate.
Rudder: 20mm low rate 30mm high rate.
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3) Double check the balance of the airplane. Do this with the fuel tank empty.
4) Check the control surfaces. All should
move in the correct direction and not bind in
any way.
6) Check to ensure the control surfaces
are moving the proper amount for both low
and high rate settings.
8) Properly balance the propeller . An out
of balance propeller will cause excessive vibration which could lead to engine and/or airframe failure.
We wish you many safe and enjoyable
flights with your YAK 55.
7) Check the receiver antenna. It should
be fully extended and not coiled up inside the
fuselage.
5) If your radio transmitter is equipped
with dual rate switches double check that they
are on the low rate setting for your first few
flights.
2) Check every bolt and every glue joint
in the Y AK 55 to ensure that everything is tight
and well bonded.
F)From behind the airplane, look at the
aileron on the right wing half. Move the aileron
stick to the right. The right aileron should move
up and the other aileron should move down. If
it does not, flip the servo reversing switch on
your transmitter to change the direction.
PREFLIGHT CHECK.
1) Completely charge your transmitter
and receiver batteries before your first day of
flying.
FLIGHT PREPARATION.
A) Check the operation and direction of
the elevator, rudder, ailerons and throttle.
C) Check the elevator first. Pull back on
the elevator stick. The elevator halves should
move up. If it they do not, flip the servo reversing switch on your transmitter to change
the direction.
B) Plug in your radio system per the
manufacturer's instructions and turn everything on.
E)Check the throttle. Moving the throttle
stick forward should open the carburetor barrel. If it does not, flip the servo reversing switch
on your transmitter to change the direction.
D) Check the rudder. Looking from behind the airplane, move the rudder stick to the
right. The rudder should move to the right. If it
does not, flip the servo reversing switch on
your transmitter to change the direction.
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