Seagull Models JUMPER 25 User manual

Jumper 25
HIGH WING TRAINER - ENGINE SIZE .25 - 2STROKE
Jumper 25
HIGH WING TRAINER - ENGINE SIZE .25 - 2STROKE
Jumper 25
Hand-made Almost Ready to Fly R/C Model Aircraft
ASSEMBLY MANUAL
Additional items required
Engine
4 Channel or greater Radio Control system
Glues
Tools
Starting Equipment
Speci cations
Wingspan
______________________________
, 157cm
Wing area
____________________________
1256Cm2
Approximate  ying weight
__________________
, 2.5kg
Recommended engine size
___
0.25-0.32 cu. ins 2-stroke
Recommended R/C
_____________
4 channel minimum
Flying skill level
__________________
High wing Trainer
Kit features
•
Ready-made—minimal assembly &  nishing required
•
Ready-covered—including decals, trim & covering
•
Factory-installed pushrod
•
Factory-installed metal engine mount
•
Factory-pinned & glued control surface hinges for ultimate safety
•
Comprehensive hardware pack including wheels, tank, spats,undercarriage& spinner
•
Photo-illustrated step-by-step Assembly Manual
Made in Vietnam
Distributed throughout Europe by:
J Perkins Distribution Ltd, Kent, UK.
http://www.jperkinsdistribution.co.uk

Jumper 25
Instruction Man u al
2
Thank you for choosing the
Jumper 25
ARTF by SEAGULL MODELS. The
Jumper 25
was designed
with the in ter me di ate/advanced sport  yer in mind. It is a High-wing aeroplane which is easy to
 y and quick to assemble. The airframe is con ven tion al ly built using balsa, plywood and veneer
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. The pushrods are pre-made to
the correct lengths, the motor mount has been  tted and the hinges are pre-installed and pinned
for security. Flying the
Jumper 25
is simply a joy.
This instruction manual is designed to help you build a great  ying aeroplane. Please read this
manual thoroughly before starting assembly of your
Jumper 25
. Use the parts listing below to
identify all parts.
We encourage you to let us know your comments. Fill out the consumer feedback survey at the back of
this manual, send us a letter or contact us at [email protected]. or [email protected](Australi
a) or [email protected](Vietnam).
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 &
RE SPON SI BIL I TY.
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 offer a variety of training procedures
designed to help the new pilot on his way to successful R/C  ight. They will also be able to advise on any
insurance and safety regulations that may apply.

25-32 2-stroke engine

4-channel radio with four servos

Glow plug to suit engine

Propeller to suit engine

Protective foam rubber for radio
system

Silicone fuel line

Stick-on weights for balance
(If necessary)

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
FUSELAGE ASSEMBLY

(1) Fuselage

(1) Pre-installed throttle pushrod &
tube

(1) Pre-installed servo tray

(1) Pre-installed motor mount

(1) Pre-installed rudder pushrod

(1) Pre-installed elevator pushrod
WING ASSEMBLY

(1) Right wing half with pre-installed
aileron

(1) Left wing half with pre-installed
aileron

(1) Plywood wing dihedral brace

(1) Covering strip for centre section
joint
TAIL SECTION ASSEMBLY

(1) Vertical stabilizer with pre-in-
stalled rudder

(1) Horizontal stabilizer with pre-in-
stalled elevator halves

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Instruction Man u al
3
HARDWARE PACK

(1) Moulded plastic fuel tank

(1) Pre-assembled fuel tank stop per

(1) Weighted fuel pick-up (clunk)

(2) Main wheels

(1) Undercarriage

(2) 3 x 12mm metal screws for spin ner

(4) 3 x 250mm metal screws for main
u/c

(1) Spinner with backplate

(4) Wheel collars with four 3 x 18mm set
screws

(2) 140mm long threaded rod for aileron
pushrods

(5) Nylon clevises

(1) Adjustable servo connector

(5) Nylon snap keepers

(5) 3 x 350mm machine screws, washers
& nuts

(5) Nylon adjustable control horns

(2) Nylon wing bolts

(4) 4 x 30mm machine screws

(8) 4mm washers

(4) 4mm nuts
NOTE:
To avoid scratching your new aer o plane
we sug gest that you cover your work-
bench with an old towel. Keep a couple
of jars or bowls handy to hold the small
parts after you open the bags.
Please trial  t all parts. Make sure you
have the correct parts and that they  t
and are aligned prop er ly be fore gluing!
This will ensure proper as sem bly as the
Jumper 25
is made from nat u ral ma-
terials and minor ad just ments may have
to be made.
The paint and plastic parts used in this kit
are fuel proof. How ev er, they are not tol-
erant of many harsh chem i cals in clud ing
the fol low ing: paint thinner, cyano-acr-
ylate glue ac cel er a tor, cy anoacr ylate
glue de-bonder and acetone. Do not let
these chem i cals come in contact with the
colours on the covering and the plas tic
parts.
WING ASSEMBLY
NOTE:
We highly recommend using 30 minute
epoxy as it is stronger and provides
more working time, al low ing the builder
to properly align the parts. Using fast cure
epoxy when joining the wing halves could

2.
Test  t the dihedral brace into each wing
half. The brace should slide in easily up
to the centreline that you drew. If not, use
220 grit sandpaper with a sanding block
and sand down the edges and ends of
the brace until it  ts properly.
NOTE:
The dihedral brace is cut in the shape
of a “V”. This shape gives the wing the
correct dihedral angle. Make sure you
do not test  t the brace upside down.

3.
Remove the brace when sat is  ed with
its  t in each wing half. Coat both sides
of one half of the di he dral brace with 30
minute epoxy. Next, pour some epoxy into
the dihedral box in one wing panel. Make
sure you cover the top and bottom as well
as the sides of the dihedral brace. Use
enough epoxy to  ll any gaps.

4.
Insert the dihedral brace into the di he dral
box up to the centreline. With paper tow-
els wipe off any ex cess epoxy that may
have squeezed out of the joint .
result in the glue drying before the wing
halves are aligned properly which may
result in failure of the wing cen tre section
during  ight.

1.
Locate the plywood wing dihedral brace.
Using a ruler, locate its centre and draw
a vertical line .
Dihedral brace
Draw centreline

Jumper 25
Instruction Man u al
4

5.
Once the epoxy has cured, trial  t
both wing halves together. The cen tre
ribs should  t together  ush with no
gaps. If gaps do exist, use 220 grit
sandpaper and sand down the high
spots on the root ribs and the wing
joiner until a proper  t is achieved. The
correct amount of dihedral is ready-
built into the wings. With one wing half
laid  at on the table, the other wing
tip should be ap prox i mate ly 8cm off
the table surface. If this needs to be
adjusted, you may do so by sanding
small amounts from the cen tre ribs
or dihedral brace.

6.
Carefully apply masking tape around
the top and bottom edge of the root
rib of each wing half to protect them
from damage caused by epoxy.

7.
Mix a generous amount of 30 minute
epoxy. Coat the exposed half of the
dihedral brace, and the remaining
wing joiner box and both root ribs
with epoxy. Slide the two wing halves
to geth er and carefully align them at
the leading and trailing edges. Wipe
away any excess epoxy using paper
tow els. Use mask ing tape wrapped
around the centre section to hold
the halves in place until the epoxy
cures.
PARTS REQUIRED
SERVO INSTALLATION
INSTALLING THE AILERON SERVO MOUNT

{1}
Plywood Aileron Servo Mount

1)
Install the rubber grommets and brass
collets onto the aileron servo. Test  t the ser vo
into the ai le ron servo mount.
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.

2)
Remove the aileron servo. Place the
mount onto the wing, aligning the cutout in the
mount with the cutout in the wing. The two
notches in the mount should face the leading
edge of the wing.

3)
While holding the servo mount  rmly
in place, trace around it using a pen.

4)
Remove the mount, and using a
mod el ing knife, carefully remove the covering
from inside the outline you drew.

5)
Using Kwik Bond 5 Minute Epoxy,
glue the servo mount into place. Remove
any ex cess epoxy using a paper towel and
rubbing alcohol. Use pieces of masking tape
to hold the tray in place until the ep oxy fully
cures.
Servo tray
Servo tray

8.
When the epoxy has cured, care ful ly
remove the masking tape from the
wing.

9.
Peel off the backing from the self ad-
he sive covering strip. Apply the strip to
the centre section of the wing starting
from the bottom trailing edge. Wrap
the strip all the way around the wing
until it meets the trailing edge again.
Trim off any excess strip.
Dihedral brace
Root Rib
Epoxy attach

Jumper 25
Instruction Man u al
5
INSTALLING THE AILERON SERVO

6)
Install the aileron servo into the servo
mount, with the output shaft towards the
lead ing edge of the wing, using the wood
screws pro vid ed with your ra dio sys tem. Drill
1/16” pi lot holes through the mount
PARTS REQUIRED
AILERON LINKAGE
INSTALLING THE AILERON LINKAGE
q
{2}
2mm x 170mm Threaded Wires
q
{2}
Nylon Adjustable Control Horns
q
{2}
Nylon Clevises
q
{2}
Adjustable Servo Connector Assemblies

1)
Thread one nylon adjustable control
horn onto each aileron torque rod. Thread the
horns on un til they are  ush with the ends of
the torque rods.

2)
Thread one nylon clevis at least 5/16”
onto each of the two 2mm x 170mm thread ed
wires.

5)
Slide the pushrod wires following
pic ture bellow.
be fore in stall ing the screws. This will pre vent
the wood from splitting.

6)
With both the aileron servo and the
ai le rons centered.

3)
With the aileron servo cen tered, in stall
the servo arm onto the ser vo. The arm should
be in stalled so it is parallel with the trailing
edge of the wing.
Connector
Pushrod
wire
PARTS REQUIRED
LANDING GEAR INSTALLATION
q
{2}
Prebent Main Gear Wires
q
{2}
60mm Diameter Wheels
q
{4}
Nylon Landing Gear Straps
q
{
8}
3mm x 12mm Wood Screws
q
{4}
Wheel Collars w/3mm x 6mm Set
Screws

Jumper 25
Instruction Man u al
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
1)
Using a modeling knife, remove
the cov er ing from over the two main gear
mount ing slots lo cat ed in the bottom of the
fu se lage.

2)
Insert the 90º bend of one main gear
wire into the predrilled hole in one mounting
slot.

3)
The land ing gear wire is held in place
us ing two nylon landing gear straps and four
3mm x 12mm wood screws.
The straps should be lo cat ed equal dis tance
from the inside and outside ends of the wire.

4)
Using the two landing gear straps as
a guide, mark the locations of the four 3mm
x 12mm mount ing screws onto the fuselage
sur face.

5)
Remove the two straps and the gear
wire. Drill four 3/32” pilot holes into the wing
for the wood screws.
INSTALLING THE MAIN GEAR WHEELS

8)
Slide one wheel collar with 3mm x
6mm set screw onto each axle. Push the
wheel collars on as far as they will go and
tight en the set screws.
Be careful not to overtighten the set
screws. Over tight en ing may cause the
threads to strip.
INSTALLING THE MAIN GEAR WIRES

Jumper 25
Instruction Man u al
7

9)
Slide one 60mm di am e ter wheel onto
each axle and push them up against the wheel
collars. Slide the remaining wheel collars with
3mm x 6mm set screws onto the axles. Push
them up against the wheels and tight en the set
screws. The wheels should spin free and not
bind in any way. If they do bind, loos en the
set screws in the outer wheel collars and move
the collars out a small amount. Re tight en the
set screws.
NOSE GEAR INSTALLATION
PARTS REQUIRED
q
{1}
Nose gear.
q
{1}
Steering arm.
q
{1}
Connector.
q
{1}
Wheel.
TOOLS REQUIRED
Installing steering arm as follow.
Adjust the nose gear steering arm until the
arm is parallel with the  re wall.
Slide one 60mm di am e ter wheel onto each
axle and push them up against the wheel
col lars. Slide the remaining wheel collars with
3mm x 6mm set screws onto the axles. Push
them up against the wheels and tight en the set
screws. The wheels should spin free and not
bind in any way. If they do bind, loos en the
set screws in the outer wheel collars and move
the collars out a small amount. Re tight en the
set screws.
INSTALLING THE MAIN GEAR WHEELS
Pushrod wire

Jumper 25
Instruction Man u al
8
PARTS REQUIRED
FUEL TANK

{1}
Molded Nylon Fuel Tank

{1}
Preassembled Stopper Assembly

{1}
Metal Weighted Pick-Up

{1}
Molded Foam Fuel Tank Support

{1}
dowell
INSTALLING THE STOPPER ASSEMBLY

1)
Using a mod el ing knife, carefully cut off
the rear portion of
one
of the two nylon tubes
leav ing 1/2” pro trud ing from the rear of the
stopper. This will be the fuel pick up tube.

2)
Using a modeling knife, cut one length
of sil i con fuel line (not included) to 2-1/4” long.
Connect one end of the line to the weighted
fuel pickup and the other end to the nylon
pick up tube.

3)
Carefully bend the second nylon
tube up at a 45º an gle. This tube is the vent
Weighted
Pick up
Fuel line
Bend tube
Vent tube
Fuel Pickup Tube
When the stop per as sem bly is installed 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.

4)
Test  t the stopper assembly into the
tank. It may be necessary to remove some
of the  ash ing around the tank opening using
a modeling knife. If  ashing is present, make
sure none falls into the tank.

5)
With the stopper assembly in place, the
weight ed pickup should rest about 3/8” away
from the rear of the tank and move free ly in side
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 stop per assembly tighten the 3mm x
20mm ma chine screw until the rubber stop per
ex pands and seals the tank opening. Do not
over tight en the as sem bly as this could cause
the tank to split.
Top of Tank
Vent tube
Fuel Pickup Tube
silicon tubing not in-
clued

Jumper 25
Instruction Man u al
9
INSTALLING THE FUEL TANK
TOOLS REQUIRED
Pushrod wire

1)
Using a modeling knife, cut one lengths
of fuel line 20” long. Connect one line to the
vent tube and one line to the fuel pick up tube
on the stopper. See picture bel low.

2)
Feed both lines through the fuel tank
com part ment and through the predrilled hole
in the  re wall. Pull the lines out from be hind
the en gine, while guid ing the fuel tank into
place. Push the fuel tank until the front of the
tank touches the  rewall.
Blow through one of the lines to ensure
the fuel lines have not become kinked
in side the fuel tank com part ment. Air should
 ow through easily.
silicon tubing not inclued
Fuel tank attachment
Pushrod wire

Jumper 25
Instruction Man u al
10
MOUNTING THE ENGINE
PARTS REQUIRED

1) Locate the second 500mm plain wire
pushrod and second 400mm nylon pushrod
housing. Install the pushrod housing through
the predrilled hole in the  rewall and into the
servo compartment. The pushrod housing
should protrude 1/4" out past the front of the
 rewall. Make a Z-Bend 1/4" from one end of
the plain wire pushrod.

2) Screw 4 pilot horns 2.5 mm diameter on
engine mount as follow.

3) Temporarily bolt the plates to the motor
mount, but do not completely tight en them
down at this time. Leave them slightly loose
so they can be moved if needed.

9) Attach the Z-Bend in the pushrod wire
to the throttle arm on the carburetor. You
will need to remove the throttle arm from the
car- buretor to be able to attach the Z-bend.
When complete, reattach the throttle arm to
the car- buretor.

10) Locate the fuel tank assembly you built
earlier. Connect two lengths of fuel line (not
in- cluded) to the tubes coming out of the tank.
Keep track which one is for the fuel pick-up
and which one is for the muf er pressure.

11) Run the tubes throught the hole in the
 rewall and slide the tank assembly into place.
The stopper of the tank should rest in the pre-
drilled hole in the  rewall.

12) Use pieces off foam rubber to hold the
tank in place. Be careful the tank or the foam
doesn’t interfere with the pushrods.
Pusrod wire
Pen

Jumper 25
Instruction Man u al
11
Jumper 25
INSTALLING THE FUSELAGE SERVOS
PARTS REQUIRED

1
Install the switch into the precut hole in
the servo tray, in the fuselage, from the bottom.
Use the two screws pro vid ed with the switch to
secure it in place. Drill two 3/32” holes through
the tray for the screws to pass through.

2
Using a 3/32” drill bit, drill a hole
through the side of the fuselage, opposite
the muf er, even with the switch.
INSTALLING THE SWITCH

3
Make a push-pull lever out of scrap
wire. At tach the wire to the switch lever and
route the wire out the side of the fuselage,
through the hole you drilled.
Switch
Some switches come with a hole drilled
through the switch tab for this very
pur pose. If your switch does not, re move the
switch and drill a 3/32” hole through the mid dle
of the switch tab.
INSTALLING THE FUSELAGE SERVOS
4. Install the rubber grommets and
brass col lets onto the elevator, rudder
and throt tle servos. Test  t the servos into
the preinstalled servo tray.Because the size
of servos differ, you may need to adjust the
size of the precut open ings in the tray.
4. Install the rubber grommets and 4. Install the rubber grommets and

5.Position the servos into the servo tray with
the output shafts orientated as shown below.
Drill 1/16” pi lot holes through the tray for each
of the mount ing screws.

Jumper 25
Instruction Man u al
12

8)
Using a modeling knife, carefully
re move the covering that overlaps the
sta bi liz er mount ing plat form sides in the
fuselage. Re move the cov er ing from both
the top and the bottom of the plat form sides.

9)
When you are sure that everything is
aligned correctly, mix up a generous amount
of Flash 30 Minute Epoxy. Apply a thin lay er to
the top and bottom of the sta bi liz er mount ing
area and to the sta bi liz er mount ing plat form
sides in the fu se lage. Slide the sta bi liz er in
place and re align. Dou ble check all of your
mea sure ments once more be fore the ep oxy
cures. Hold the sta bi liz er in place with T-pins or
mask ing tape and re move any ex cess ep oxy
using a paper tow el and rub bing al co hol.
Jumper 25
HORIZONTAL STABILIZER.
PARTS REQUIRED

{1}
Horizontal Stabilizer with Elevator
Halves
ALIGNING THE HORIZONTAL STABILIZER

1)
Using a ruler and a pen, locate the
centerline of the hor i zon tal stabilizer, at the
trail ing edge, and place a mark. Use a tri an gle
and extend this mark, from back to front,
across the top of the stabilizer. Also extend
this mark down the back of the trail ing edge
of the stabilizer.

4)
Install the wing onto the fuselage. Align
the cen ter line drawn on the top and the rear of
the sta bi liz er with the center of the fu se lage.
When that is aligned, hold the sta bi liz er in that
po si tion us ing T-pins or masking tape. Align
the hor i zon tal sta bi liz er with the wing. When
viewed from the rear, the hor i zon tal sta bi liz er
should be level with the wing. If it is not lev el,
use sand pa per and sand down the high side
of the sta bi liz er mount ing plat form until the
prop er align ment is achieved. The tips of the
sta bi liz er should also be equal dis tance from
the tips of the wing.
The top of the stabilizer does
not
have
the hinge pins exposed.

2)
Using a modeling knife, carefully
re move the cov er ing from over the vertical
sta bi liz er mount ing slot in the top of the
fu se lage.

3)
Slide the stabilizer into place in the
pre cut slot in the rear of the fuselage. The
sta bi liz er should be pushed  rmly against the
front of the slot.

5)
When you are satisfied with the
align ment, hold the stabilizer in place with T-
pins or mask ing tape, but do not glue at this
time.
MOUNTING THE HORIZONTAL STABILIZER

6)
With the stabilizer held  rmly in place,
use a pen and draw lines onto the stabilizer
where it and the fu se lage sides meet. Do this
on both the right and left sides and top and
bottom of the sta bi liz er.

7)
Remove the sta bi liz er. Us ing the lines
you just drew as a guide, carefully re move the
cov er ing from be tween them us ing a mod el ing
knife.
When cutting through the covering to
re move it, cut with only enough pres sure
to only cut through the covering it self.
Cut ting into the balsa struc ture may weak en
it.
Draw centerline

Jumper 25
Instruction Man u al
13

10)
After the epoxy has fully cured,
re move the masking tape or T-pins used to
hold the sta bi liz er in place. Carefully inspect
the glue joints. Use more ep oxy to  ll in
any gaps that may exist that were not  lled
previously and clean up the excess using a
pa per towel and rubbing alcohol.
VERTICAL STABILIZER
INSTALLATION
PARTS REQUIRED

{1}
Vertical Stabilizer with Rudder
ALIGNING THE VERTICAL STABILIZER

1)
Using a modeling knife, remove the
cov er ing from over the precut hinge slot cut
into the lower rear portion of the fuselage. This
slot ac cepts the low er rud der hinge.

2)
Slide the vertical stabilizer into the slot
in the top of the fu se lage. The rear edge of
the sta bi liz er should be  ush with the rear
edge of the fu se lage and the lower rudder
hinge should engage the precut hinge slot in
the lower fu se lage. The bottom edge of the
stabilizer should also be  rmly pushed against
the top of the hor i zon tal stabilizer.

3)
While holding the vertical stabilizer
 rm ly in place, use a pen and draw a line on
each side of the ver ti cal sta bi liz er where it
meets the top of the fuselage.

4)
Remove the stabilizer. Using a
mod el ing knife, re move the cov er ing from
below the lines you drew. Also re move the
cov er ing from the bot tom edge of the stabilizer
and the bottom and top edges of the  ll er
block. Leave the cov er ing in place on the
sides of the  ller block.
When cutting through the covering to
re move it, cut with only enough pres sure
to only cut through the covering it self.
Cut ting into the balsa struc ture may weak en
it.
Pen

Jumper 25
Instruction Man u al
14

5)
Slide the vertical stabilizer back in
place. Using a triangle, check to en sure that
the ver ti cal sta bi liz er is aligned 90º to the
hor i zon tal sta bi liz er.
Vertical
Stabilizer
Horizontal
Horizontal
Stabilizer
Stabilizer

6)
When you are sure that everything is
aligned correctly, mix up a gen er ous amount
of Flash 30 Minute Ep oxy. Apply a thin layer
to the mount ing slot in the top of the fu se lage
and to the sides and bottom of the ver ti cal
sta bi liz er mounting area. Ap ply epoxy to the
bot tom and top edges of the  ller block and
to the lower hinge also. Set the sta bi liz er in
place and re align. Dou ble check all of your
mea sure ments once more be fore the ep oxy
cures. Hold the sta bi liz er in place with T-pins or
mask ing tape and re move any ex cess ep oxy
using a paper towel and rub bing al co hol. Al low
the ep oxy to fully cure be fore pro ceed ing.
CONTROL HORN INSTALLTION

1) Locate the two nylon control horns,
three nylon control horn backplates and six 2
x 15mm machine screws.

2) Position the two elevator horns on the
bottom side of each elevator, 1 - 1/8" out from
the sides of the fuselage. The clevis at tach-
ment holes should be positioned over the
hinge line.
Control Horn
Mounting Screws
Mounting Plate

3) Using a modeling knife, remove the cov-
ering from over the two precut pushrod slots,
one on left side of the fuselage and one on the
right side of the fu se lage, under the forward
half of the horizontal sta bi liz er.

4) Using a 5/64" drill bit and the control
horns as a guide, drill the mounting holes
through the el e va tor halves.

5) Mount the control horns by inserting the
screws through the control horn bases and eleva-
tor halves, then into the mounting backplates. Do
Not overtighten the screws or the backplates may
crush the wood.

6) Position the rudder control horn on the
left side of the airplane 3/4" up from the bot-
tom of the rudder. Mount the control horn
parallel with the hor i zon tal stabilizer, not in-
line with the rudder hinge line.

7) Install the rudder control horn using the
same method as with the el e va tor control
horns.

Jumper 25
Instruction Man u al
15
PUSHROD INSTALLATION

1) Locate two nylon clevises and two ny- lon
keepers from the nylon parts tree.

2) Install the elevator pushrod into the
fuse- lage. To help make installation easier,
thread string down through the elevator push-
rod ex its and into the servo compartment in
the fu se lage. Tie the thread to the thread ed
pushrod wires of the elevator pushrod. Pull
the pushrod through the exit slots.

3) Thread the two nylon clevises onto the
thread ed wires. Attach the clevises to the
eleva- tor control horns. You may  nd it nec-
es sary to make slight bends in the wires so
they will align with the control horns without
binding.

5) Install an adjustable servo connector
in the hole closest to the center of the rud-
der servo arm. You need to use a “dual type”
servo arm. Install the connector using the
same tech nique as with the throttle.

6) Connect the elevator and rudder servos
to your radio’s receiver and turn on the sys tem.
Set the trim tabs on the trans mit ter to neutral
and center the servo arms. The el e va tor and
rudder servo arms should be per pen dic u lar
to the servos.

7) One at a time, hold the pushrods in po-
sition over the respective servos to check
for proper servo direction. If any servo turns
in the wrong direction, switch your radio’s
re vers ing switches as nec es sary to achieve
the cor rect direction.

8) Insert the nose gear pushrod wire
through the adjustable servo connector on
the rud der servo arm. Hold the nose gear
assembly in the neutral position and tighten
the set screw in the servo con nec tor. When
sat is  ed, cut off the excess wire.

9) With the elevator in neutral, mark where
the pushrod wire crosses the servo arm. At
the mark you just made, use a pair of pliers
and bend the wire up 90 degree, making an
“L” shape.

10) Remove the servo arm from the servo
and insert the wire through the outer most
hole. You may need to enlarge the hole so the
wire will  t through. Install one nylon keep er
on the wire and cut off the excess using wire
cutters. . .

11) Repeat steps #9 - #10 for the rudder
pushrod. Notice the position of the servo arms
on the servos.
See picture as follow.

4) Repeat the steps above for installing the
rud der pushrod.
See  g.19below.
Elevator pushrod
Clevis
Rudder pushrod
Clevis
Control horn
Rudder
Elevator
throttle
Switch

Jumper 25
Instruction Man u al
16
INSTALLING THE SPINNER

1)
Install the spinner backplate, pro pel ler
and spin ner cone. The spinner cone is held in
place using two 3mm x 12mm wood screws.
The propeller should not touch any part of
the spin ner cone. If it does, use a sharp
mod el ing knife and care ful ly trim away
the spinner cone where the pro pel ler
comes in contact with it.

2) Plug the four servo leads and the switch
lead into the receiver. Plug the battery pack
lead into the switch also.

3) Wrap the receiver and battery pack in
the pro tec tive foam rub ber to protect them
from vibration
INSTALLING THE RECEIVER AND BAT TERY

4)
Position the battery pack in the fuel
tank com part ment and the re ceiv er just be hind
the fuel tank . Use ex tra foam piec es to hold
them in po si tion.
When balancing the airplane you may
need to move the battery or receiver
for ward or aft to achieve prop er balance.
In our test air plane, us ing a num .25-.32 two
stroke en gine, the bat tery and re ceiv er were
mount ed as per step # 4.

5)
Using a 1/16” drill bit, drill a hole through
the side of the fu se lage, near the re ceiv er, for
the an ten na to exit. Route the an ten na out
of the fu se lage and se cure it to the ver ti cal
sta bi liz er us ing a rub ber band and a modi ed
servo arm. See picture as follow.
Antenna
Antenna
Rubber
Rubber
Rubber
Band
Modi ed
Modi ed
Servo Arm
Servo Arm
Cut
Cut

1)
It is critical that your airplane be
bal anced correctly. Improper balance will
cause your plane to lose control and crash.
The cen ter of gravity is lo cat ed 7cm back from
the lead ing edge of the wing, at the fu se lage
sides. Balance the
Jumper 25
with the fuel
tank emp ty.

2)
Mount the wing to the fuselage. Us ing
a cou ple of pieces of masking tape, place them
on the top side of the wing7cm back from the
lead ing edge, at the fuselage sides.

3)
Turn the airplane , place your  n gers
on the mask ing tape and care ful ly lift the
plane.

4)
If the nose of the plane falls, the plane
is nose heavy. To correct this  rst move the
bat tery pack fur ther back in the fuselage. If
this is not possible or does not correct it, stick
small amounts of lead weight on the fuselage
sides under the hor i zon tal sta bi liz er. If the tail
of the plane falls, the plane is tail heavy. To
cor rect this, move the bat tery and re ceiv er
forward or
if this is not pos si ble, stick weight
onto the  rewall or use a brass heavy hub
spinner hub, similar to those offered by Harry
Higley. When bal anced cor rect ly, the air plane
should sit lev el or slight ly nose down when you
lift it up with your  ngers.
BALANCING
You should cut
from pushrod of
throlte or nose gear

Jumper 25
Instruction Man u al
17
CONTROL THROWS

1)
We highly recommend setting up the
Jumper 25
us ing the control throws listed at
right. We have list ed con trol throws for both
initial test  ying/sport  y ing and aerobatic
 y ing.

2)
Turn on the radio system, and with the
trim tabs on the transmitter in neutral, center
the con trol surfaces by making adjustments to
the clevises or ad just able servo con nec tors.
The servo arms should be cen tered also.

3)
When the elevator, rudder and ai le ron
con trol surfaces are centered, use a ruler
and check the amount of the control throw in
each surface.
The control throws should
be mea sured at the wid est point of each
sur face!
INITIAL FLYING/SPORT FLY ING
Ailerons:
3/16” up
3/16” down
Elevator:
5/16” up
5/16” down
Rudder:
3/4” right
3/4” left
AEROBATIC FLY ING
Ailerons:
Ailerons:
Ailerons:
Ailerons:
3/8” up
3/8”
down
Elevator:
5/8” up
5/8”
down
Rudder:
1-1/4” right
1-1/4” lef
t
1-1/4” left1-1/4” lef
Do not use the aerobatic settings for ini tial
Do not use the aerobatic settings for ini tial
Do not use the aerobatic settings for ini tial
test  ying or sport  ying.
test  ying or sport  ying.
Do not use the aerobatic settings for ini tial
test  ying or sport  ying.
Do not use the aerobatic settings for ini tial

4)
By moving the position of the
ad just able con trol horn out from the control
sur face, you will de crease the amount of throw
of that con trol sur face. Moving the adjustable
con trol horn to ward the con trol sur face will
in crease the amount of throw.
FLIGHT PREPARATION

1)
Check the operation and di rec tion of
the el e va tor, rudder, ailerons and throttle.

A)
Plug in your radio sys tem per
the man u fac tur er's in struc tions and turn
ev ery thing on.

B)
Check the elevator  rst. Pull back
on the elevator stick. The el e va tor halves
should move up. If it they do not,  ip the
ser vo reversing switch on your trans mit ter to
change the direction.

C)
Check the rudder. Look ing from
be hind the air plane, move the rudder stick to
the right. The rud der should move to the right.
If it does not,  ip the servo reversing switch
on your trans mit ter to change the di rec tion.

D)
Check the throttle. Mov ing
the throt tle stick forward should open the
car bu re tor bar rel. If it does not,  ip the servo
re vers ing switch on your trans mit ter to change
the di rec tion.

E)
From behind the air plane, look at
the ai le ron on the right wing half. Move the
ai le ron stick to the right. The right aileron
should move up and the oth er ai le ron should
move down. If it does not,  ip the servo
re vers ing switch on your trans mit ter to change
the di rec tion.

2)
Check Control Surface Throw.

A)
The Rudder should move 3/4” left
and 3/4” right from cen ter. If it moves too far,
turn the adjustable control horn out away from
the rud der. Do the op po site if there is not
enough throw.

B)
Both elevator halves should move
5/16” up and 5/16” down from center. If they
move too far, turn the adjustable control horns
out away from the elevator halves. Do the
op po site if there is not enough throw. Both
el e va tor halves should also trav el the same
amount through out their total move ment.

C)
The ailerons should move 3/16” up
and 3/16” down from center. If the ailerons

Jumper 25
Instruction Man u al
18
move too much, turn the adjustable control
horns out away from the wing. Do the op po site
if there is not enough throw. It is im por tant
that both ai le rons move the same amount,
both up and down.

D)
Once the control throws and
move ments are set, tubing must be added to
the cle v is es to ensure they do not release in
the air. Cut a piece of fuel line into  ve 1/4”
long pieces. Unsnap the clevises and slip
one piece over each clevis. Snap the clevises
back in place and slide the tubing up over
them.
PREFLIGHT CHECK

1)
Completely charge your transmitter
and re ceiv er batteries before your  rst day of
 ying.

2)
Check every bolt and every glue joint
in the PC-9 to ensure that everything is tight
and well bond ed.
We wish you many safe and en joy a ble
 ights with your
Jumper 25
.

8)
Properly balance the propeller. An
out of balance propeller will cause excessive
vi bra tion which could lead to engine and/or
air frame fail ure.

3)
Double check the balance of the
air plane. 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 surfaces
are mov ing the proper amount for both low
and high rate set tings.

7)
Check the receiver antenna. It should
be ful ly extended and not coiled up inside the
fu se lage.

Hand-made Almost Ready to Fly R/C Model Aircraft
ASSEMBLY MANUAL
Additional items required
Engine
4 Channel or greater Radio Control system
Glues
Tools
Starting Equipment
Made in Vietnam
Speci cations
Wingspan
______________________________
, 145cm
Wing area
____________________________
4100Cm2
Approximate  ying weight
__________________
, 2.5kg
Recommended engine size
___
0.32-0.46 cu. ins 2-stroke
_____________________________
0.52 cu. ins 4-stroke
Recommended R/C
_____________
4 channel minimum
Flying skill level
__________________
Low wing Trainer
Kit features
•
Ready-made—minimal assembly &  nishing required
•
Ready-covered—including decals, trim & covering
•
Factory-installed pushrod
•
Factory-installed metal engine mount
•
Factory-pinned & glued control surface hinges for ultimate safety
•
Comprehensive hardware pack including wheels, tank, spats,undercarriage& spinner
•
Photo-illustrated step-by-step Assembly Manual
SEAGULL 40
LOW WING TRAINER
LOW WING TRAINER
LOW WING TRAINER

Additional items required
Engine
4 Channel or greater Radio Control system
Glues
Tools
Starting Equipment
Made in Vietnam
Speci cations
Wingspan
_______________________________
161cm
Wing area
__________________________
4025 sq. cm.
Approximate  ying weight
________________
2.6-2.9kg
Recommended engine size
___
0.40-0.46 cu. ins 2-stroke
Recommended R/C
_____________
4 channel minimum
Flying skill level
______________
Intermediate/advanced
Kit features
•
Ready-made—minimal assembly &  nishing required
•
Ready-covered—including decals, trim & covering
•
Factory-installed pushrods
•
Factory-installed metal engine mount
•
Factory-pinned & glued control surface hinges for ultimate safety
•
Comprehensive hardware pack including wheels, tank, spats,undercarriage& spinner
•
Photo-illustrated step-by-step Assembly Manual
PC-9
semi Scale ARF Model
Engine size .40-.46 Cu. Ins 2- stroke
Hand-made Almost Ready to Fly R/C Model Aircraft
ASSEMBLY MANUAL