Hobby King J3 NAVY CUB User manual

CONTENTS
Introduction 1
Features 1
Specification 1
Contents 2
Tools And Items 3
Assembly of the front landing gears 4
Assembly of horizontal tail & 5
vertical tail and tail wheel
Assembly of main wings, 6-7
front landing gear and propeller
Centre of Gravity 7
Pre-Flight Check 8
Flight 8-9
Tips 9
Problem Solving 10
Notes 11-12

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INTRODUCTION
Thank you for purchasing H-king’s Piper J3 Navy Cub Electric R\C airplane, Piper is a Propeller
airplane which is ideal for the beginners, seasoned flyer’s and scale enthusiasts.
The Navy cub will perform most aerobatic manoeuvres from loops to stall turns, low slow flyby’s is the
best thing about flying the navy cub. Made from tough EPO foam means it will handle all the bumps
and repairing any damage is a breeze. In order to fly the Piper, please make sure you read through
the instructions carefully before attempting to operate the model for the first time.
You alone are responsible for the safe operation of your radio-controlled model. Young people should
only be permitted to operate this model under the instruction and supervision of an adult who is aware
of hazards involved in this activity.
FEATURES:
- Authentic Scale scheme. (Thank you JB)
- Perfect aerobatic manoeuvres, such as
rolls,loops, and stall turns.
- Stable invert flight.
- Excellent scale performance.
- Excellent stability of nosing up and down.
- Controllable landings and easy to fly.
- Modular design easy to replace the spare
parts.
SPECIFICATION
(BRUSHLESS
VERSION)
- Wingspan (approx): 1400mm (55”)
- Length: 950 mm
- Flying weight: 1800g
- Wing load: 56 g/dm²
- 45A ESC, Powerful 3648 Brushless out-
runner motor with 700kv
- 4 x 9g servos
- Battery: 2200mHa 3~4S LiPo Battery

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CONTENTS
1. Cowl
2. Fuselage
3. Main Wing
4. Horizontal Wing
5. Landing gear set
6. Vertical Wing
7. Propeller
8. Wing Rod
9. Prop Adaptor
10. Motor
11. Spare Parts
12. ABS plastic
wing support
13. Inclined strut
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TOOLS AND ITEMS
To assemble this airplane you need to prepare some tools.
Cutter Knife
Pliers
Screwdriver
Nippers
Triangle
Scissors

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ASSEMBLY OF THE FRONT LANDING GEARS:
Glue the steel wire to Glue the front wheel to the steel wire.Glue the stand of the the Gear cover of
front front landing gears to landing gear. the gear cover.
Attach springs to landing gear and use heatshrink
to cover springs.
Screw the wheel into the steel wire in Screw the wheel chock and wheel into the steel clockwise
direction. wire to ensure the flexible rotation of wheel.
Prepared the front landing
gears as shown.
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ASSEMBLY OF HORIZONTAL TAIL
& VERTICAL TAIL & TAIL WHEEL:
Install the screw horns Install the Rudder plate in the
horizontal tail. in the vertical tail.
(PA1.7X15mm 4pcs)
Install the horizontal tail in fuselage with screw.
(PM3.0mmX30mm 2 pcs)
Install the vertical tail and screw onto fuselage with screw.
（PM3.0X45mm 1pcs, PM3.0X40mm 1pcs).
Install the rear landing gear with glue.
Install the screw horns in the
steering holder with screw.
(PA1.7X15mm 2pcs)
Fix the rear landing gear
with screw. (PA2.6X8mm
2pcs)
Fix one end of the control arm in the steering holder, the other end to steering arm, close the
chuck after leveling elevator. (0.5X4X24.8mm 2pcs)
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ASSEMBLY OF MAIN WINGS,
PROPELLER:
FRONT LANDING GEAR AND
Install the control leveling aileron. horns of
aileron. (1.2X65mm 2pcs)
(PA1.7X15mm 8 pcs)
Install the steel wire with the second hole on servo arm, close the chuck after.
Put reinforcing rod into the holes on left and right wing with two ends. Then
fasten reinforcing rod with screws.
Connect two steering devices with Y wire. Install the main wing and cabin with screws. The Y wire
will reach equipment bay after (PM3.0X35mm 2pcs) through the hole on cockpit.
Put inclined strut into Fix front landing gear
the right hole on with steel wire. main wing.
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Tighten diagonal draw bar and dam-board with screws. (PA2.6X20mm)
Fix the horizontal wing and vertical wing with stree wire.
(Spring: 0.5X4X24.1mm 8pcs) (For horizontal 1.0X94mm 2pcs For vertical 1.0*94mm 2 pcs)
Fix propeller into the spindle of motor. Then tighten it up with spacer and screw.
CENTER OF GRAVITY
PRE-FLIGHT CHECK
1. Check wings and control surfaces for alignment and damage. Check all connections for control
services. Check all screws and glued surfaces.
2. Check the propeller, adaptor and undercarriage.
3. Check the H-King Navy Cub’s Centre of Gravity. (CoG)
4. Always turn your transmitter on before powering your RC plane.
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5. Switch the transmitter on, then switch the receiver on.
6. Always perform a range check with your transmitter. Make sure your plane is secure to prevent
damage to people and property.
7. Check plane responds properly to control signals.
8. Re-check all your control services, airframe, screws and undercarriage etc.
9. If there is no interference, the plane is now ready to fly.
FLIGHT
Take-off:
1. Face into the wind, slowly increase the throttle, use the rudder to keep the cub flying straight. Slowly
add elevator and throttle to rotate and become airborne.
2. Start to turn your cub downwind slowly gaining height, once at height and you are comfortable with
the flying attitude of your plane start your trimming of your control surfaces. With 50% of throttle the
cub should fly straight and level.
3. Be careful not to over control the plane, just keep steady and straight and climb to a safe height. At
this point you should start to make circular climbs and then into level flight. Become more familiar with
your H-King Navy Cub. As your flying confidence develops the more manoeuvres you can add to your
flying.
Flight:
1. The plane should fly level at around 50% of full throttle.
2. The flight time will be prolonged if you allow the plane to sometimes glide at a safe altitude.
Landing:
Now you have flown your first flight, it’s time to land. Make sure you do a practice approach. After this
approach start your landing pattern beginning with a downwind leg, reducing throttle to slow the cub to
a suitable speed. Turn onto your base leg part of the circuit, use your rudder elevator and ailerons to
fly a co-ordinated turn. Turn onto final approach keep flying the cub straight using the rudder to adjust
yaw control, the elevator controls your attitude and the throttlecontrols your altitude. Using thismethod,
the cub is easy to control. Slowly decrease throttle and slowly fly the cub onto its main landing gear
when cub settles on its main landing gear then you can slowly cut the throttle and slowly apply elevator

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to get the tail gear to rest. You have now finished your first flight. Taxi your plane and safely remove
the flight battery and power off your transmitter.
TIPS
1. Train yourself with an RC flight model simulator, before you fly the H-King J3 Navy Cub electric RC
airplane. It will help you with coordination for when fly your model.
2. Taxi the J3 Navy Cub on the ground to learn the direction control of the plane.
Please remember when the plane fly's towards to you the aileron and rudder control direction is
reversed.
3. Flying with the assistance of an experienced flyer will help your first-time flight.
4. Do not fly in the strong wind or inclement weather.
5. Always face the wind when taking off and landing.
6. Do not fly the plane above or behind you, this can lead to disorientation, always fly the plane in front
of the flight line and never behind.
7. Please consider purchasing a spare battery pack for longer flights.
8. Do not fly this plane with damaged or broken parts this may result in accidents or injury. Spare parts
are available via our website.
PROBLEM SOLVING:
Phenomenon
Typical error
Problem solving
Motor do not
work
1. The battery is not full charged
2. The battery of the transmitter
in low power.
3. There is some broken circuit
in the plane
1. Charge the battery
2. Replace the battery in the
transmitter.
3. Check motor ESC
connection.

1
0
Cannot fly in
a line
1. Motor/esc connection error
1. Swap around any 2 of
the 3 ESC/motor wire
connections
Cannot climb
1. The servo lead is connected to
Rx incorrectly.
2. The servo is damaged.
1. Make sure the servo leads
are connected properly.
2. Replace servo.
Short control
distance
1. Control surfaces not centered.
2. CoG is not in the correct
position.
1. Adjust the trims on the
transmitter.
2. Re-position lipo as
suggested.

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