The World Models Manufacturing Happy-Fly User manual

0.25 cubic inch displacement 2 stroke ( glow)
Radio required: 4 channels, 4 servos airplane radio
Wing SpanWing Span
Wing AreaWing Area
Flying WeightFlying Weight
Fuselage LengthFuselage Length
431 sq in / 27.8 sq dm431 sq in / 27.8 sq dm
3.5 lbs / 1500 g3.5 lbs / 1500 g
40.5 in / 1030 mm40.5 in / 1030 mm
* Specifications are subject to change without notice.** Specifications are subject to change without notice.*
Wa r ni n g ! T h i s m o d e l i s n o t a t o y.
It is designed for maximum performance. Please seek advice if one is not familiar with this kind
of engine powered precision model. Operating this model without prior preparation may cause
injuries. Remember, safety is the most important thing. Always keep this instruction manual
at hand for quick reference.
THE WORLD MODELS
MANUFACTURING CO., LTD.
FACTORY PRE-FABRICATED
ALMOST-READY-TO-FLY(ARF)SERIES
MADE IN CHINA
www.theworldmodels.com
45.5 in /1160mm45.5 in /1160mm
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SpecificationsSpecifications
INSTRUCTION MANUALINSTRUCTION MANUAL

INDEXINDEX
BEFORE YOU BEGINBEFORE YOU BEGIN
PARTS LISTPARTS LIST
ASSEMBLYASSEMBLY
SAFETY PRECAUTIONSSAFETY PRECAUTIONS
P. 1P. 1
P. 2P. 2
P. 3 -9P. 3 -9
P.9P.9
BEFORE YOU BEGINBEFORE YOU BEGIN
Read through the manual before you begin, so you will have an overall idea of what to do.
P. 1
Symbols used throughout this instruction manual comprise of the following : -
Apply epoxy glue. Apply epoxy glue.
Assemble left and right
sides the same way.
Assemble left and right
sides the same way.
Peel off shaded portion
covering film.
Peel off shaded portion
covering film.
Drill holes with the specified
diameter (here: 3mm).
Drill holes with the specified
diameter (here: 3mm).
Pay close attention here!Pay close attention here!
Pierce the shaded portion
covering film.
Pierce the shaded portion
covering film.
Do not overlook this symbol!Do not overlook this symbol!
Must be purchased separately!Must be purchased separately!
Cut off shaded portion.Cut off shaded portion.
Ensure smooth non-binding
movement while assembling.
Ensure smooth non-binding
movement while assembling.
Apply instant glue
(C.A.glue, super glue.)
Apply instant glue
(C.A.glue, super glue.)
Check all parts. If you find any defective or missing parts contact your local dealer. Please DRY FIT
and check for defects for all parts that will require CA or Epoxy for final assembly. Any parts you
find to be defective after the gluing process may be difficult to remove for warranty replacement. The
manufacturer will replace any defective parts, but will be difficult to extend to the good parts that are
good before gluing to defective parts during assembly.

Parts List
1. FUSELAGE -- 1 pc.
2. MAIN WING -- 1 pair
3. STABILIZER & ELEVATOR -- 1 set
5. FUEL TANK 200cc -- 1 set
6. SPINNER 40mm --1 pc.
9. FRONT LANDING GEAR -- 1 pc.
8. WHEEL 50mm --3 pcs
4. VERTICAL FIN & RUDDER -- 1 set
10. MAIN LANDING GEAR -- 1 pair
12. PUSHROD:--
METAL ROD 1.6x310mm w/Plastic Tube
(For Front Landing Gear) -- 1 set
METAL ROD 1.8x120mm (For Elevator & Rudder ) -- 2 pcs
METAL ROD 1.8x85mm w/Threads (For Alieron) -- 2 pcs
METAL ROD 1.8x220mm w/Threads (For Elevator -- 1 pc.
METAL ROD 1.8x240mm w/Threads (For Rudder) -- 1 pc.
13. THROTTLE PUSHWIRE 1.2 x 340mm
w/Plastic tube d2xD3x160mm -- 1 set
P. 2
18. DECALS: ST 200 017 --1 set
17. FUEL TUBE 6 x 5mm -- 6 pcs
HEAT-SHRINK TUBE 8x40mm -- 4 pcs
14. WOODEN PARTS :--
BALSA WOOD 10x 10 x 66mm (For Fixing Fuel Tank ) --1 pc.
PLYWOOD 6 x 16 x100mm (Wing Joiner) --1 pc.
PLYWOOD 3 x 12 x 30mm ( For Aileron Servo) --2 pcs.
15 PLASTIC PARTS :--
CLEVIS -- 4 pcs
STRAPER -- 2 pcs
RUBBER BAND 60 x 4mm -- 4 pcs
STEERING ARM --1 pc.
16. METAL PARTS :--
LINKAGE CONNECTOR -- 4 sets
COLLAR 3.6mm w/set screw -- 7 sets
NUT 3mm -- 8 pcs
SCREW PA3 x 10mm -- 4 pcs
SCREW PM2 x 12mm -- 4 pcs
WASHER d3xD7mm -- 8 pcs
SCREW PM3 x 25mm -- 4 pcs
11. FIN TIP 3x19x70mm -- 1 pc.
7. SPONGE 10x80x200mm (For Radio equipment) -- 2 pcs
PLYWOOD 3 x 66 x106mm (Servos Stand) --1 pc.
WOODEN 6 x 102 (For Fixing Wing) --2 pcs.
WOODEN 8 x 300 (For Elevator & Rudder Servos) --2 pcs.
HORN -- 2 sets
RING 2.3mm -- 2 pcs
STEERING ARM STAND --1 pc.
PLATE (For Main Landing Gear) -- 2 pcs
SCREW PA2.6 x 12mm -- 4 pcs

Main WingMain Wing
11
Aileron ServoAileron Servo
33
P. 3
Aileron ServoAileron Servo
22
Securely glue together. If coming
off during flights, you lose control
of your airplane which leads to
accidets!
Plywood
3 x 12 x 30mm
Plywood
3 x 12 x 30mm
Cut out the covering film
1mm
Straper
Fuel Tube
6 x 5mm -- 4 pcs
Clevis
Ring

P. 4
Landing GearLanding Gear
55
Front WheelFront Wheel
66
3mm Set Screw 4
3
3.6mm Collar
3mm Set Screw
Front Wheel
PushWire
Steering Arm
Front View
3mm Set Screw
Completed
Way A:Way A:
Way B:Way B:
For Way B
3.6mm Collar
3.6mm Collar
3.6mm Collar
44 Landing Gear Landing Gear

P. 5
77Fuel TankFuel Tank
Fuel Tank 200cc
Fuel Tank
Install Balsa 10 x 10 x 66mm
(For fixing fuel tank)
Top View
EngineEngine
88
PM3 x 25mm Screw
3mm Washer
3mm Nut
44
88
88
3mm
Throttle Pushwire
w/plastic tube
3mm
PM3 x 25mm
Install Engine position
95mm
3.74 in
Spinner
40mm
3mm
StabilizerStabilizer
99
Peel off shaded portion
covering film
A
A'A =
A'
Tempo rar y ins ta ll t he m a in wi ng , a dj us t
leveling of t he s ta bi lizer t o m ake i t a s
pa rallel t o t he m ain wi ng a s po ssibl e.
(Stabilizer)
(Main Wing)
BB'

Vertical FinVertical Fin
1010
P. 6
A A'
A = A'
Servo SetServo Set
1111
LINKAGE CONNECTOR
3 x 3mm Set Screw
4
4
4
2mm Nut
2mm Washer
4
2mm
2mm
3mm
Throttle Pushwire,
Rudder Pushrod,
Elevator Pushrod.
2mm
Included with the Radio Set.
Throttle Servo.Rudder Servo.
Elevator Servo.
Please refer to attached sheet for linkage stopper installation.
Radio EquipmentRadio Equipment
1212
ron
Ft
Throttle Pushwire
Front Wheel
Pushwire
Elevator Pushrod
Rudder Pushrod
Top View
Linkage Connector
Wooden Rod
Ø8x300mm
Metal Rod
Ø1.8x120mm
Plywood 3x66x106mm

P. 7
Radio EquipmentRadio Equipment
1313 Install and arrange the servo as shown in the diagram.
Throttle
Servo
Servo
Elevator
Servo
Rudder
Top View
Recevier
Battery
Fuel Tank
1414 Rudder PushrodRudder Pushrod
PM 2 x 12mm Scre w
2
Rudder Pushrod
PM2 x12mm
Line up the holes
of the horn to the
edge of the rudder.
See diagram.
Rudder
Clevis
horn
Fuel Tube
6 x 5mm
Horn
1515
Elevator PushrodElevator Pushrod
PM 2 x 12mm Scre w
2
Servo
To Elevator 6 x 5 m m
F u e l T u b e
Cl e v i s
PM 2 x 12mm
Horn
L in e u p t h e h ol e s
o f t he h o r n t o t h e
e dg e o f t h e e l e va to r.
S ee d i a gr a m .
Bo t t o m Vi e w
Elevator horn

P. 8
1717 Wing SettingWing Setting
1818 Control ThrowsControl Throws
1616 Main WingMain Wing
60 x 4mm Rubber Band
8
Rubber Band
St 1
ep
t
Sep2
3Step
4
Step
Mount the rubber bands following step
one to step four and repeat once. In t
otal, eight rubber bands are used for
mounting.
Adjust the wing and fuselage configuration
shown as in the diagrams.
A = A'
B = B'
C = C'
A A'
B B'
C C'
Elevator
Rudder
Aileron
10mm
10mm
20mm
20mm
5mm
5mm
Adjust the control throws as shown in
the diagram. These throws are good for
general flying. You can adjust according
to your personal preference.
Wooden Ø6x102mm

C. G.C. G.
1919
85mm85mm
3.35 in3.35 in
The ideal C.G. position is 85mm(3.35 in.) behind
the leading edge measured at where the wing meets
the fuselage. In order to obtain the C.G. specified,
add weight to the fuselage or move the battery
position. Check the C.G. before flying.
Important Safety PrecautionsImportant Safety Precautions
# First time flyer should never fly by himself / herself. Assistance from experienced flyer is# First time flyer should never fly by himself / herself. Assistance from experienced flyer is
absolutely necessary. absolutely necessary.
#Pre-flight adjustment must be done before flying, it is very dangerous to fly a badly#Pre-flight adjustment must be done before flying, it is very dangerous to fly a badly
pre-adjusted aircraft. pre-adjusted aircraft.
#Make sure the air field is spacious, never fly the plane too close to people and never get#Make sure the air field is spacious, never fly the plane too close to people and never get
too close to a running propeller. too close to a running propeller.
#If you find wrinkles on the covering as a result of weather changes, you can use hot iron#If you find wrinkles on the covering as a result of weather changes, you can use hot iron
to remove the wrinkles. Please begin with lower temperature setting and gradually raise to remove the wrinkles. Please begin with lower temperature setting and gradually raise
the temperature until the wrinkles are gone. Too hot an iron may damage the covering. the temperature until the wrinkles are gone. Too hot an iron may damage the covering.
#Check and re-tighten up all factory assembled screws, use thread locker if applicable. #Check and re-tighten up all factory assembled screws, use thread locker if applicable.
# HAPPY FLY 20 is specially designed to be powered by 0.25 2 stroke glow# HAPPY FLY 20 is specially designed to be powered by 0.25 2 stroke glow
engine, using a more engine, using a more
powerful engine does not mean better performance. In fact, over powerful engine does not mean better performance. In fact, over
powered engine may powered engine may cause severe damge and injuries.cause severe damge and injuries.
A022S0606

LINKAGE CONNECTORLINKAGE CONNECTOR
HW7111030 & HW7111060
Drill 2mm hole at servo horn.
Insert linkage connector
into servo horn.
Make sure shoulder of
screw is cleared from
servo horn.
Add washer to reduce
play if necessary.
Shoulder
Tighten up the round nut
against the shoulder. Apply
CA or permanent thread
locker.
After fastening the round nut, make sure that
the linkage connector can rotate freely.
Product Registration Form (US Customers)Product Registration Form (US Customers)
We would like to share with you any relevant information regarding your model, including
product news and free upgrade parts when applicable. Please fill in the following and send to
1.Name:
2.Address:
3.Phone #: e-mail:
4.Model:
Wing QC# Fuselage QC#
(QC numbers are stamped on wing and fuselage)
5.Date of Purchase:
6.Store Name:
Please call AirBorne Models at 925 371 0922 for any assistance in filling this form.
Thank you very much for purchasing our product.
Air Borne Models,2403,Research Drive ,Livermore, CA 94550.U.S.A.

Warbirds
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A022S0606