Seagull Models SEAX139 User manual

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ASSEMBLY MANUAL
Code: SEAX139
www.seagullmodels.com
“ Graphics and specications may change without notice “ .
(SEAX139R)
(SEAX139W)
Specications:
Wingspan---------------50.4 in ( 128 cm).
Wing area---------------375 sq.in (24.2 sq.dm).
Weight-------------------2.8-3.1 lbs (1.25-1.4 kg).
Length-------------------33.8 in (85.8 cm).
Recommend engine size-------Motor 480
--------------------------------------Power 15 or Power 25
Radio---------------------4 channels with 4 servos.

SHOESTRING 25e EP Instruction Manual.
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ank you for choosing the SHOESTRING 25e EP ARTF by SEAGULL MODELS
COMPANY LTD,. e SHOESTRING 25e EP was designed with the intermediate/ad-
vanced sport yer in mind. It is a semi scale airplane which is easy to y and quick to as-
semble. e 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 nd
that most of the work has been done for you already. e motor mount has been t-
ted and the hinges are pre-installed. Flying the SHOESTRING 25e EP 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 SHOESTRING 25e EP . Use the
parts listing below to indentify all parts.
Please be awere 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.
INTRODUCTION.
WARNING.
KIT CONTENTS
1
5
2
3
3
2
4
6 7

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KIT CONTENTS.
SEAX139 SHOESTRING 25e EP
SEAX13901 Fuselage
SEAX13902 Wing set
SEAX13903 Tail set
SEAX13904 Cowling
SEAX13905 Wheel pants
SEAX13906 Aluminum tube
SEAX13907 Landing gear
ADDITIONAL ITEMS REQUIRED.
480 Motor size
Or Power 15 or Power 25
Computer radio with 4 servos.
Glow plug to suit engine.
Propeller to suit engine.
Protective foam rubber for radio
system.
TOOLS & SUPPLIES NEEDED.
ick 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.
HINGING THE AILERON.
Note : e control surfaces, including the ai-
lerons, elevators, and rudder, are prehinged
with hinges installed, but the hinges are not
glued in place. It is imperative that you prop-
erly adhere the hinges in place per 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) 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 wing
panel until the T-pin is snug against the wing
panel. is will help ensure an equal amount
of hinge is on either side of the hinge line
when the aileron is mounted to the aileron.
3) Slide the wing panel on the aileron until
there is only a slight gap. e hinge is now
centered on the wing panel and aileron. Re-
move the T-pins and snug the aileron against
the wing panel. A gap of 1/64” or less should
be maintained between the wing panel and
aileron.
Hinge.

SHOESTRING 25e EP Instruction Manual.
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4) Deect the aileron and completely satu-
rate each hinge with thin C/A glue. e ailer-
ons 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.
NOTE : e hinge is constructed of a spe-
cial 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.
C/A glue.
8) Aer both ailerons are securely hinged,
rmly grasp the wing panel and aileron to
make sure the hinges are securely glued and
cannot be pulled out. Do this by carefully ap-
plying medium pressure, trying to separate
the aileron from the wing panel. Use caution
not to crush the wing structure.
5) Turn the wing panel over and deect 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.
1) Remove the servo cover from the wing.
Do not let the string fall into the wing as it is
used to pull the servo lead through the wing.
2) Place the servo between the tabs on the
servo cover with the output of the servo over
the opening in the cover. With the servo
spaced slightly o the cover, use a pencil to
mark the location for the servo mounting
screws.
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.
Work the aileron up and down sev-
eral times to “work in” the hinges
and check for proper movement.
Note :
INSTALLING THE AILERON SERVOS.
7) Repeat this process with the other wing
panel, securely hinging the aileron in place.

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3) Use a drill bit to drill the holes for the ser-
vo mounting screws.
4) Use a screwdriver to thread a servo
mounting screw into each of the holes to cut
threads in the surrounding wood. Remove
the screw before moving to the next step.
6)Secure the servo using the screws provided
with the servo and a screwdriver. e output
sha of the servo will align with the opening
in the cover.
7) Fit the servo horn to the servo so it is per-
pendicular to the servo.
8) Use string or dental oss to secure a servo
extension to the aileron servo lead.
5) Apply 2-3 drops of thin CA in each of the
holes to harden the surrounding wood. is
will harden the threads so the screws do not
easily strip the surrounding wood.
C/A glue.
9) Use the string to pull the extension
through the wing root.
1.5mm

SHOESTRING 25e EP Instruction Manual.
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10) Apply 1-2 drops of thin CA in each
of the holes to harden the surrounding
wood for the aileroon cover screws.
12) Use a drill bit to drill the two holes
completely through the aileron for the ai-
leron control horn mounting screws. e
holes have already been started and are
easily found on the bottom of the aileron.
13) Attach the control horn to the aileron
using two 2x12m metal screws and a con-
trol horn backplate. Use a screwdriver to
tighten the screws.
11) Set the aileron hatch in place and use
screwdriver to install it with four metal
screws.
2x12mm

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M2 clevis. Hex nut.
Fuel tubing.
Repeat steps to install the remaining ai-
leron control horn and pushrod.
1) e blind nuts for securing the land-
ing gear are already mounted inside the
fuselage.
4) Use hobby scissors and a hobby knife
to trim the landing gear fairings. Leave
the size of the fairings slightly over-sized.
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 M4x15mm and wash-
ers. Make sure to use the threadlock on
the bolts so they don’t vibrate loose.
INSTALLING THE MAIN LANDING
GEAR TO FUSELAGE.
M4x15mm
read locker glue.
C/A glue.
M4x15mm

SHOESTRING 25e EP Instruction Manual.
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WHEELS AND WHEEL PANTS.
6) Fit the landing gear fairings over the
gear. Slowly trim the fairing to t to the
fuselage. When installed, they will cover
the area where the landing gear attaches
to the fuslage.
1) Remove the hardware from the axle.
Place a drop of light machine oil on the
axle to help the wheel roll freely.
2) Slide the axle into the wheel.
3) Slide the wheel into the wheel pant.
C/A glue.

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4) Repeat above steps to install the re-
maining wheel and wheel pant on the
landing gear.
ELECTRIC POWER CONVERSION.
Please see below pictures.
1) Route the leads for the motor through
the hole in the rewall.
2) Loop a tie-wrap ( not included)
through the plate in the fuselage right
above the landing gear plate. Make sure
the tie-wrap is not looped through the
battery mounting plate.
3x20mm

SHOESTRING 25e EP Instruction Manual.
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3) Slide the speed control into the fuse-
lage with the battery wires, receiver lead
and switch going in and through the tie-
wrap. Position the speeed control, then
tighten the tie-wrap to secure the speed
control in the fuselage. e heat sink will
face the top of the fuselage.
4) Connect the wires from the motor to
the wires of the speed control. Use a tie-
wrap ( not included) to secure the leads
so they don’t interfere with the operation
of the motor or installation of the cowl-
ing.
5) Route the battery lead through the
opening in the fuselage. e lead for the
receiver is routed under the battery tray
and receiver, then plugged into the throt-
tle channel of the receiver. Mount the
switch from the speed control in the fu-
selage where it can be accessed when the
canopy is removed.
6) Secure the battery in the fuselageusing
a hook and loop strap. Also, place hook
and loop tape on the battery and fuselage
where they contact each other to prevent
the battery from moving.
Receiver.
Battery.

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COWLING.
e cowl can now be secured to the fuse-
lage using the four 2x6mm metal screws.
1) Locate the items for this section of the
manual.
Holes.
Please see below pictures.
INSTALLING THE PROPELLER.
e 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 propel-
ler comes in contact with it.
HINGING THE ELEVATOR.

SHOESTRING 25e EP Instruction Manual.
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STABILIZER INSTALLATION.
1) Using a ruler and a pen, locate the
centerline of the horizontal stabilizer, at
the trailing edge, and place a mark. Use a
triangle and extend this mark, from back
to front, across the top of the stabilizer.
Also extend this mark down the back of
the trailing edge of the stabilizer.
2) Using a modeling knife, carefully re-
move the covering at mounting slot of
horizontal stabilizer ( both side of fuse-
lage).
3) Slide the stabilizer into place in the
precut slot in the rear of the fuselage. e
stabilizer should be pushed rmly against
the front of the slot.
Draw center line
2) Carefully remove the elevator from
one of the horizontal stabilizer panels.
Note the position of the hinges.
Glue the elevator hinges in place using
the same techniques used to hing the ai-
lerons.
Glue the ruder hinges in place using the
same techniques used to hing the ailer-
ons.
3) Remove each hinge from the horizon-
tal stabilizer panel and elevator and place
a T-pin in the center of each hinge. Slide
each hinge into the elevator until the T-pi
n is snug against the elevator. is will
help ensure an equal amount of hinge is
on either side of the hinge line when the
elevator is mounted to the horizontal sta-
bilizer panel.
HINGING THE ELEVATOR.

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.
4) With the stabilizer held rmly in place,
use a pen and draw lines onto the stabi-
lizer where it and the fuselage sides meet.
Do this on both the right and le sides
and top and bottom of the stabilizer.
5) Remove the stabilizer. Using the lines
you just drew as a guide, carefully remove
the covering from between them using a
modeling knife.
When cutting through the covering to
remove it, cut with only enough pressure
to only cut through the covering itself. Cut-
ting into the balsa structure may weaken
it.
6) Using a modeling knife, carefully re-
move the covering that overlaps the sta-
bilizer mounting platform sides in the
fuselage. Remove the covering from both
the top and the bottom of the platform
sides.
Trim and cut
Epoxy
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 top and bottom of the stabi-
lizer mounting area and to the stabilizer
mounting platform sides in the fuselage.
Slide the stabilizer in place and realign.
Double check all of your measurements
once more before the epoxy cures. Hold
thestabilizerin placewithT-pinsormask-
ing tape and remove any excess epoxy us-
ing a paper towel and rubbing alcohol.

SHOESTRING 25e EP Instruction Manual.
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INSTALLING VERTICAL STABILIZER.
90º
Vertical
Stabilizer.
Horizontal
Stabilizer.
1) Using a modeling knife, remove the
covering from over the precut hinge slot
cut into the lower rear portion of the fu-
selage. is slot accepts the lower rudder
hinge.
3) While holding the vertical stabilizer
rmly in place, use a pen and draw a
line on eachside of the vertical stabilizer
where it meets the top of the fuselage.
4) Slide the vertical stabilizer back in-
place. Using a triangle, check to ensure
that the vertical stabilizer is aligned 90º
to the horizontal stabilizer.
2) Slide the vertical stabilizer into the slot
in the top of the fuselage. e rear edge
of the stabilizer should be ush with the
rear edge of the fuselage and the lower
rudder hinge should engage the precut
hinge slot in the lower fuselage. e bot-
tom edge of the stabilizer should also be
rmly pushed against the top of the hori-
zontal stabilizer.
Remove covering.
Epoxy.
Epoxy.

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SERVO AND PUSHROD
INSTALLATION.
1) Place the rudder servo in the fuselage
with the output sha to the front of the
fuselage. Position the servo so the edge
toward the center is centered in the open-
ing. Use a pencil to transfer the positions
for the mounting screws on the servo
tray.
2) Remove the servo from the fuselage.
Use a pin vise and drill bit to drill the four
holes for the servo mounting screws.
4) Place 2-3 drops of thin CA in each hole
to harden the surrounding wood.
5) Insert the Z-bend from the pushrod
wire through the hole in the servo horn.
3) Use a screwdriver to thread a servo
mounting screw into each of the holes
to cut threads in the surrounding wood.
Remove the screw before moving to the
next step. Prepare all four mounting
holes at this time.
in CA.
1.5mm

SHOESTRING 25e EP Instruction Manual.
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6) Use a pin vise and drill bit to drill the
two locations for the control horn mount-
ing screws. e locations have been pre-
drilled at the factory.
8) Repeat above steps to connect the el-
evator pushrod wire. e positions and
measurements for the elevator connec-
tions are the same as the rudder.
7) Secure the control horn to the rudder
using two 2x12mm metal screws and a
control horn backplate. 1) If all the decals are precut and ready to
stick. Please be certain the model is clean
and free from oily ngerprints and dust.
Position decal on the model where de-
sired, using the photos on the box and aid
in their location.
APPLY THE DECALS.
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 cer-
tain the model is clean and free from oily
ngerprints and dust. Position decal on
the model where desired, using the pho-
tos on the box and aid in their location.
Elevator pushrod.
Rudder pushrod.
2mm

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Slide the aluminum tube into fuselage.
Insert canopy hatch into fuselage as be-
low pictures.
ATTACHMENT WING- FUSELAGE.
Insert two wing panels as pictures below.
Use a clip to secure the wing to the fu-
selage.
Wing tube.
BALANCING.
1) It is critical that your airplane be
balanced correctly. Improper balance will
cause your plane to lose control and
crash. THE CENTER OF GRAV-
ITY IS LOCATED 60 to 66mm BACK
FROM THE LEADING EDGE OF
THE WING AT THE WING ROOT.
3) With the model upright, place your
ngers on the masking tape and carefully
li the plane.
2) Mount the wing to the fuselage. Using
a couple of pieces of masking tape, place
them on the bottom side of the wing 60
to 66mm back from the leading edge of
the wing at the wing root.
4) Do not turn plane upside down. Only
low wing models should be turned up-
sidedown for balancing. Remove this
paragraph, it is not intended for use in
the instructions. it is a note for you.High
Wing models must be balanced upright.

SHOESTRING 25e EP Instruction Manual.
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Accurately mark the balance point on the
botttom of the wing on both sides of the
fuselage. e balance point is located 60
to 66mm back from the leading edge of
the wing at the wing root. is is the bal-
ance point at which your model should
balance for your rst ights. Later, you
may wish to experiment by shiing the
balance up to 10mm forward or back to
change the ying characteristics. Mov-
ing the balance forward may improve the
smoothness and arrow- like tracking, but
it may then require more speed for take
o and make it more dicult to slow
down for landing. Moving the balance a
makes the model more agile with a light-
er and snappier ”feel”. In any case,please
start at the location we recommend .
With the wing attached to the fuselage,
all parts of the model installed ( ready to
y), and empty fuel tanks, hold the model
at the marked balance point with the sta-
bilizer level.
Li the model. If the tail drops when
you li, 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.
*If possible, rst attempt to balance the
model by changing the position of the re-
ceiver battery and receiver. If you are un-
able to obtain good balance by doing so,
then it will be necessary to add weight to
the nose or tail to achieve the
proper balance point.
CONTROL THROWS.
60 to 66 mm
Ailerons:
High Rate
Up: 10mm
Down: 6mm
Low Rate
Up: 8mm
Down: 5mm
Elevator:
High Rate
Up: 7mm
Down: 6mm
Low Rate
Up: 5mm
Down: 4mm
Rudder:
High Rate
Right: 17mm
Le: 17mm
Low Rate
Right: 15mm
Le: 15mm

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SHOESTRING 25e EP Instruction Manual.
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FLIGHT PREPARATION. PREFLIGHT CHECK.
Check the operation and direction
of the elevator, rudder, ailerons and
throttle.
A) Plug in your radio system per the
manufacturer’s instructions and turn
everything on.
B) Check the elevator rst. Pull
back on the elevator stick. e eleva-
tor halves should move up. If it they do
not, ip the servo reversing switch on
your transmitter to change the direc-
tion.
C) Check the rudder. Looking from
behind the airplane, move the rudder
stick to the right. e rudder should
move to the right. If it does not, ip
the servo reversing switch on your
transmitter to change the direction.
D) Check the throttle. Moving the
throttle stick forward should open the
carburetor barrel. If it does not, ip the
servo reversing switch on your trans-
mitter to change the direction.
E) From behind the airplane, look
at the aileron on the right wing half.
Move the aileron stick to the right.
e right aileron should move up and
the other aileron should move down.
If it does not, ip the servo reversing
switch on your transmitter to change
the direction.
1) Completely charge your trans-
mitter and receiver batteries before
your rst day of ying.
2) Check every bolt and every glue
joint in the SHOESTRING 25E EP to
ensure that everything is tight and
well bonded.
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.
5) If your radio transmitter is
equipped with dual rate switches
double check that they are on the low
rate setting for your rst few ights.
6) Check to ensure the control sur-
faces are moving the proper amount
for both low and high rate settings.
7) Check the receiver antenna.
It should be fully extended and not
coiled up inside the fuselage.
We wish you many safe and enjoyable ights
with your SHOESTRING 25E EP.
8) Properly balance the propeller.
An out of balance propeller will cause
excessive vibration which could lead
to engine and/or airframe failure.