J-3 Cub 25 ARF
Assembly Manual
Table of Contents
Introduction
Introduction ................................................................2
Contents of Kit/Parts Layout
Specifications .............................................................3
Covering Colors
Required Electronics & Accessories
Outrunner (Direct Drive) Motor Setup
Required Tools and Adhesives
Optional Accessories
Warning ....................................................................5
Before Starting Assembly
Note on Lithium Polymer Batteries
Using the Manual
Limited Warranty Period
Landing Gear Installation
Motor and Cowling Installation
Radio Installation
Wing Assembly
Tail Installation
Linkage Installation
Final Assembly
Center of Gravity / Battery Installation
Control Throws
Flying Notes
2006 Official AMA
National Model Aircraft Safety Code
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The Piper J-3 Cub is an all-time favorite among aviation
enthusiasts everywhere. Classic lines and predictable flight
performance are just a few of the Cub’s trademarks. The
25-size J-3 Cub from E-flite™ is the first of its size for
E-flite. The name Piper J-3 Cub .25 ARF implies the power
of a .25 glow engine, but it is designed specifically for
electric operation. This aircraft has been designed from
the start for the E-flite Power 25 Outrunner BL motor.
It uses balsa and plywood construction and is covered
with genuine UltraCote®. Using a scale of approximately
1/7, the J-3 Cub spans 62 inches delivering excellent
presentation and performance to budget-minded pilots.
You can fly with either a 10-cell Ni-MH battery, or a
3-cell Li-Po for increased performance and duration. An
optional set of scale fiberglass floats is also available
(EFLA500). All it takes is five minutes to change from
landing gear to floats to enjoy those afternoons on the
lake. Change back to the standard landing gear and you
can be shooting touch-and-go’s at the local flying field, the
choice is yours. Either way we believe you will fall in love
with the relaxing flight performance of the E-flite J-3 Cub.
2
Specifications
Covering Colors
Wingspan: 62 in (1575mm)
Length: 35.5 in (900mm)
Wing Area: 552 sq in (35.5 sq dm)
Weight w/o Battery: 3.2 lb (1.45 kg)
4.5 lb w/Floats (2.0 kg)
Weight w/Battery: 4 lb (1.8 kg)
5.3 lb w/Floats (2.4 kg)
Contents of Kit/Parts Layout
Large Replacement Parts:
EFL4001 Wing w/Ailerons
EFL4002 Fuselage
EFL4003 Tail Set
EFL4004 Landing Gear
EFL4005 Cowling
EFL4009 Tailwheel Assembly
Small Replacement Parts:
EFL4006 Windshield/Window Set
EFL4007 Pushrod Set
EFL4008 Main Wheels
Cub Yellow HANU884
Black HANU874
3
Required Electronics & Accessories
Required Tools and Adhesives
Complete Radio System
JSP16000** JR SPORT™ 6-Channel Radio System
Or Purchase Separately
JSP30600 RS600 6-Channel Receiver w/o Crystal
JRPXFR** FM Receiver Crystal
JSP20040 MN48 Mini Servo (4)
JSP98020 6" Y-Harness
JSP98110 6" Servo Extension (2)
JRPA212 Long Servo Arm (2)
Outrunner Motor Setup
EFLA4025A Power 25 BL Outrunner Motor, 870Kv
EFLA312B 40-Amp Brushless Speed Control
APC12060E Electric Propeller, 12 x 6E
THP42003S2PPL 4200 3S2P, 11.1V Li-Po, 13 GA
EFLC3005 Celectra™ 1–3 Cell Li-Po Charger
Or
EFLB4010 1800mAh Ni-MH, 10-Cell
Tools
Small Phillips Screwdriver
(EFLA257 - included with EFLA250)
Hex Wrench: 7/64"
(EFLA251 - included with EFLA250)
Drill T-pins
Ruler Felt-tipped pen
String Square
Tape Pliers
Hobby scissors Side cutters
Sandpaper Rubbing alcohol
Paper towel/tissue Masking tape
Petroleum jelly Hobby knife
Drill bit: 1/16" (1.5mm), 5/64" (2mm),
3/32" (2.5mm), 1/8" (3mm)
Adhesives
Thin CA 6-Minute Epoxy (HAN8000)
Medium CA 30-Minute Epoxy (HAN8002)
Canopy glue
Threadlock
4
Optional Accessories
Note on Lithium Polymer Batteries
EFLA110 Power Meter
EFLA500 Float Set, 25-Size
Warning
An RC aircraft is not a toy! If misused, it can cause
serious bodily harm and damage to property. Fly
only in open areas, preferably at AMA (Academy of
Model Aeronautics) approved flying sites, following
all instructions included with your radio.
Keep loose items that can get entangled in the propeller
away from the prop, including loose clothing, or other
objects such as pencils and screwdrivers. Especially
keep your hands away from the propeller.
Before Starting Assembly
Before beginning the assembly of your J-3 Cub,
remove each part from its bag for inspection. Closely
inspect the fuselage, wing panels, rudder and
stabilizer for damage. If you find any damaged or
missing parts, contact the place of purchase.
Lithium Polymer batteries are significantly
more volatile than alkaline or Ni-Cd/
Ni-MH batteries used in RC applications.
All manufacturer’s instructions and warnings
must be followed closely. Mishandling of
Li-Po batteries can result in fire. Always follow
the manufacturer’s instructions when disposing
of Lithium Polymer batteries.
Using the Manual
This manual is divided into sections to help make
assembly easier to understand, and to provide
breaks between each major section.
Remember to take your time and follow the directions.
Limited Warranty Period
Horizon Hobby, Inc. guarantees this product to be free
from defects in both material and workmanship at the
date of purchase.
5
Limited Warranty & Limits of Liability
Pursuant to this Limited Warranty, Horizon Hobby, Inc.
will, at its option, (i) repair or (ii) replace, any product
determined by Horizon Hobby, Inc. to be defective. In the
event of a defect, these are your exclusive remedies.
This warranty does not cover cosmetic damage or damage
due to acts of God, accident, misuse, abuse, negligence,
commercial use, or modification of or to any part of the
product. This warranty does not cover damage due to
improper installation, operation, maintenance, or attempted
repair by anyone other than an authorized Horizon Hobby,
Inc. service center. This warranty is limited to the original
purchaser and is not transferable. In no case shall Horizon
Hobby’s liability exceed the original cost of the purchased
product and will not cover consequential, incidental or
collateral damage. Horizon Hobby, Inc. reserves the right to
inspect any and all equipment involved in a warranty claim.
Repair or replacement decisions are at the sole discretion
of Horizon Hobby, Inc. Further, Horizon Hobby reserves
the right to change or modify this warranty without notice.
REPAIR OR REPLACEMENT AS PROVIDED UNDER
THIS WARRANTY IS THE EXCLUSIVE REMEDY
OF THE CONSUMER. HORIZON HOBBY, INC.
SHALL NOT BE LIABLE FOR ANY INCIDENTAL
OR CONSEQUENTIAL DAMAGES.
As Horizon Hobby, Inc. has no control over use,
setup, final assembly, modification or misuse, no
liability shall be assumed nor accepted for any
resulting damage or injury. By the act of use, setup
or assembly, the user accepts all resulting liability.
If you as the purchaser or user are not prepared to
accept the liability associated with the use of this product,
you are advised to return this product immediately in
new and unused condition to the place of purchase.
Safety Precautions
This is a sophisticated hobby product and not a toy. It must
be operated with caution and common sense and requires
some basic mechanical ability. Failure to operate this product
in a safe and responsible manner could result in injury or
damage to the product or other property. This product is not
intended for use by children without direct adult supervision.
The product manual contains instructions for safety,
operation and maintenance. It is essential to read
and follow all the instructions and warnings in the
manual, prior to assembly, setup or use, in order to
operate correctly and avoid damage or injury.
6
Questions, Assistance, and Repairs
Your local hobby store and/or place of purchase cannot
provide warranty support or repair. Once assembly,
setup or use of the product has been started, you must
contact Horizon Hobby, Inc. directly. This will enable
Horizon to better answer your questions and service
you in the event that you may need any assistance.
Questions or Assistance
For questions or assistance, please direct your
email to productsupport@horizonhobby.com, or call
877.504.0233 toll free to speak to a service technician.
Inspection or Repairs
If your product needs to be inspected or repaired, please
call for a Return Merchandise Authorization (RMA). Pack
the product securely using a shipping carton. Please note
that original boxes may be included, but are not designed
to withstand the rigors of shipping without additional
protection. Ship via a carrier that provides tracking and
insurance for lost or damaged parcels, as Horizon Hobby,
Inc. is not responsible for merchandise until it arrives and
is accepted at our facility. Include your complete name,
address, phone number where you can be reached
during business days, RMA number, and a brief summary
of the problem. Be sure your name, address, and RMA
number are clearly written on the shipping carton.
Warranty Inspection and Repairs
To receive warranty service, you must include your original
sales receipt verifying the proof-of-purchase date. Providing
warranty conditions have been met, your product will be
repaired or replaced free of charge. Repair or replacement
decisions are at the sole discretion of Horizon Hobby.
7
Non-Warranty Repairs
Should your repair not be covered by warranty and the
expense exceeds 50% of the retail purchase cost, you will
be provided with an estimate advising you of your options.
You will be billed for any return freight for non-warranty
repairs. Please advise us of your preferred method of
payment. Horizon Hobby accepts money orders and cashiers
checks, as well as Visa, MasterCard, American Express,
and Discover cards. If you choose to pay by credit card,
please include your credit card number and expiration date.
Any repair left unpaid or unclaimed after 90 days will be
considered abandoned and will be disposed of accordingly.
Electronics and engines requiring inspection or repair should
be shipped to the following address (freight prepaid):
Horizon Service Center
4105 Fieldstone Road
Champaign, Illinois 61822
All other products requiring inspection or repair should
be shipped to the following address (freight prepaid):
Horizon Product Support
4105 Fieldstone Road
Champaign, Illinois 61822
Landing Gear Installation
Required Parts
• Fuselage • Landing gear
• Hub cap (2) • Tie wrap (6)
• Inner wheel hub (2) • Outer wheel hub (2)
• 4mm wheel collar (2) • 3mm setscrew (2)
• Landing gear strap (4)
• Landing gear fairing (2)
1
• 2
/
" (63mm) foam wheel (2)
2
• 2mm x 15mm sheet metal screw (8)
• 2mm x 10mm sheet metal screw (8)
Required Tools and Adhesives
• Phillips screwdriver • Hex wrench (included in kit)
• Side cutter
Note: The fuselage is designed to accept either
the standard landing gear or optional floats.
Changing from landing gear to floats requires
less than 5 minutes. Refer to the manual
included with your floats for proper installation.
8
1. Place the landing gear in position with the larger
diameter wire to the front of the fuselage. Secure
the gear using four landing gear straps and eight
2mm x 10mm sheet metal screws.
2. Slide the inner wheel hub onto the landing
gear. (The holes in the inner hub do not go
through the hub.) Slide a 4mm wheel collar onto
the landing gear and secure it using a 3mm
setscrew. Use threadlock when tightening the
setscrew onto the flat spot of the landing gear.
9
3. Press the 2
1
/
" (63mm) foam wheel onto
2
the inner hub. Press the outer wheel hub into
the wheel. Complete the assembly using four
2mm x 15mm sheet metal screws.
4. Press the hub cap into the outer wheel hub.
10
5. Attach the landing gear fairing to the landing
gear using three tie straps. Trim the excess strap
side cutters.
6. Repeat Steps 2 through 5 to complete the landing
gear installation.
11
Motor and Cowling Installation
Required Parts
• Fuselage
• Cowling
• Hook and loop straps (2)
• 6-32 x 1/2" socket head screw (4)
• 2mm x 10mm sheet metal screw (4)
• Propeller adapter
• 12 x 6 electric propeller (APC12060E)
• Brushless outrunner motor
• Electronic speed control
• Battery
Required Tools and Adhesives
• Hex wrench: 7/64"
• Drill
• Drill bit: 1/16" (1.5mm), 1/8" (3mm)
Note: It is very important to be sure the
propeller is balanced before installing it onto
the motor.
1. Prepare the outrunner motor by attaching the
X-mount to the motor using screws supplied with
the motor.
12
2. Attach the motor to the firewall using four
6-32 x 1/2" socket head screws included with
the J-3 Cub.
3. Attach the motor to the speed control. Secure
the speed control in the fuselage using hook and
loop material so it will not move during flight.
Note: The firewall has been prepared to mount
the E-flite™ Power 25 brushless motor. It may
be necessary to remove the blind nuts and drill
new mounting holes for other motor choices.
Note: Ensure you mount the speed control with
the label towards the fuselage sidewall. This
will assure maximum cooling for the speed
control.
13
4. Use hook and loop material to secure the battery
into the fuselage.
Note: Now would be a good time to plug the
speed control into the receiver and check the
operation of the motor. It should rotate counterclockwise when viewed from the front of the
fuselage. Once the operation of the motor has
been checked, unplug the battery and attach
the battery hatch.
5. Slide the cowling onto the fuselage. Place the
propeller adapter onto the motor and attach the
propeller using the adapter.
14
6. Position the cowling so it lines up with the
propeller and adapter. Allow for 1/8” (3mm)
clearance between the propeller and cowl. Drill
four 1/16" (1.5mm) holes for the cowl mounting
screws. Enlarge the holes in the cowling only
using a 1/8" (3mm) drill bit. Secure the cowling
using four 2mm x 10mm sheet metal screws.
15
Radio Installation
Required Parts
• Fuselage
• Receiver
• Mini Servo (2)
• 6" Y-harness
Required Tools and Adhesives
• Drill • Drill bit: 1/16" (1.5mm)
1. Install the servo grommets and brass eyelets
on the rudder and elevator servos following
the instructions provided with the servos or
radio system.
Note: The servo openings in the fuselage are
set up for the JR SPORT® (MN48) Mini Servos.
2. Center the servo in the servo opening. Use a
1/16" (1.5mm) drill bit to drill the locations for
the servo mounting screws.
16
3. Secure the servo using the screws provided with
the servo. Repeat Step 2 for the remaining servo.
4. Plug the rudder, elevator and speed control into
the receiver, as well as the aileron Y-harness.
Use hook and loop to secure the receiver in the
fuselage. Route the antenna wire through the tube
in the fuselage.
Note: Do not cut the receiver antenna wire
as it will greatly reduce the range of your
radio system.
17
Wing Assembly
Required Parts
• Clevis (2) • Clevis retainer (2)
• Pushrod wire keeper (2) • CA hinge (6)
• Mini Servo (2) • 6" servo extension(2)
• Cub yellow covering strip
• Wing panel (left and right)
• Aileron (left and right)
• Plywood wing joiner (2)
• Aileron servo cover (left and right)
• 3/4" x 3/8" x 3/8"
(19mm x 10mm x 10mm) servo block (4)
• Control horn w/backplate (2)
• 2mm x 20mm screw (4)
• 2mm x 10mm sheet metal screw (8)
• 4" (100mm) linkage wire (2)
• Long Servo Arm (JRPA212) (2)
Required Tools and Adhesives
• 6-minute epoxy • Phillips screwdriver
• Thin CA • T-pins
• Drill • Felt-tipped pen
• 30-minute epoxy
• Drill bit: 1/16" (1.5mm), 5/64" (2mm)
• String • Masking tape
1. Place a T-pin in the center of three hinges.
18
2. Drill a 1/16" (1.5mm) hole in the hinge
center of both the aileron and wing.
3. Place the hinges in the aileron.
19
4. Slide the aileron and wing together. Remove
the T-pins. There should be a 1/64" (.4mm) gap
between the aileron and wing. Make sure the
aileron can move freely without binding.
5. Deflect the aileron and apply thin CA to
each of the hinges. Make sure to saturate each
hinge. Apply CA to both the top and bottom
of the hinges.
Note: The aileron has a block installed for
the aileron control horn to mount to. Make
sure this block is located on the inboard side
of the wing.
20
Note: Do not use accelerator in the hinging
process. The CA must be allowed to soak into
each hinge naturally.
6. Install the grommets and brass eyelets
into the aileron servo. Attach a 6" (152mm)
servo extension, securing it with thread or a
commercially available clip. Center the servo and
install a long servo arm onto the servo.
7. Check to make sure you are using the correct
servo hatch for the wing panel. Simply place the
hatch in position to make sure the opening for the
servo horn aligns.
21
8. Position the servo onto the servo hatch with
the servo arm centered in the slot. Use a felttipped pen to mark the locations for the servo
mounting blocks.
9. Use 6-minute epoxy to glue two 3/4" x 3/8"
x 3/8" (19mm x 10mm x 10mm) servo blocks
to the servo hatch. Allow the epoxy to fully cure
before moving to the next step.
22
10. Place the servo into position between the
mounting blocks. Mark the location for the servo
mounting screws using a felt-tipped pen.
Note: The servo should not rest against the
hatch to isolate it from vibrations.
11. Use a 1/16" (1.5mm) drill bit to drill the
holes in the servo mounting blocks for the screws.
Secure the servo using the screws provided with
the servo.
Note: Make sure the servo is centered before it
is completely mounted and trim the servo arm
as shown.
23
12. Pass the servo lead from the servo opening
to the hole in the root of the wing.
Note: A weight tied to a string can be
used first, then tied to the servo lead to
pull it through.
13. Secure the servo hatch to the wing using
four 2mm x 10mm sheet metal screws.
24
14. Slide a clevis retainer onto a clevis,
then thread the clevis onto a 4" (100mm)
linkage wire. Thread the clevis on at least
12 turns to start.
15. Remove the backplate from a control horn.
Snap the clevis to the horn and position the horn
so the holes are aligned with the hinge line and
the pushrod is aligned with the servo arm. Use
a felt-tipped pen to mark the locations for the
control horn screws.
25
16. Use a 5/64" (2mm) drill bit to drill the
locations for the control horn screws.
17. Attach the control horn using two 2mm x
20mm screws and the control horn backplate.
26
Note: Turn on the transmitter and verify all trims
and sub-trims are centered. Next, plug in the
aileron servo and verify it is centered for the
following steps.
18. Mark the pushrod where it crosses the
control horn using a felt-tipped pen.
19. Bend the pushrod wire 90 degrees at the
mark made in the last step. Drill a 5/64" (2mm)
hole in the servo arm and pass the wire through
the hole. Secure the wire using a pushrod wire
keeper. Cut the excess wire using side cutters.
20. Repeat Steps 1 through 19 for the remaining
aileron and servo.
27
21. Apply a thin coat of 6-minute epoxy to one side
of a wing joiner. Use clamps to hold a second
joiner to the first until the epoxy fully cures.
22. Once the epoxy has had time to cure, sand any
excess epoxy from the joiner. Test fit the joiner
into one wing panel. Sand the joiner if necessary
so the joiner fits properly.
28
23. Fit the two wing panels together using the
joiner. The panels must fit together with no gaps.
Sand if necessary for a perfect fit.
Note: Make sure you are certain of the fit of
the joiner before proceeding.
24. Mix up 1/2 oz (15ml) of 30-minute epoxy.
Apply epoxy to both the wing joiner and the
joiner opening of both wing panels. Slide the
joiner into a wing panel, and then slide the
remaining panel in position. Use clips and tape
to hold the two panels tightly together until the
epoxy has fully cured.
Note: Use rubbing alcohol and paper towels
to wipe away any excess epoxy before it has
time to cure.
29
25. Use a covering iron to apply the covering to the
center of the wing over the joint.
Tail Installation
Required Parts
• Fuselage • Assembled wing
• 8-32 x 1
• Stabilizer w/elevators • Rudder w/fin
Required Tools and Adhesives
• Phillips screwdriver • Felt-tipped pen
• 6-minute epoxy • Paper towels
• Rubbing alcohol • Square
• Hobby knife • Ruler
1. Attach the wing using two #8 washers and two
8-32 x 1
1
/
" screw (2) • #8 washer (2)
8
1
/
" bolts.
8
30
Note: It may be necessary to lightly sand
" "
""
the tab at the front of the wing to get the
wing to fit.
2. Slide the stabilizer into the slot at the rear of the
fuselage. Center the stabilizer as shown.
3. Check that the wing and stabilizer are parallel.
Lightly sand the opening in the fuselage if
adjustments are required.
31
4. Measure from each tip of the stabilizer to a point
" "
""
at the forward center of the fuselage. Adjust the
stabilizer so both measurements are equal.
5. Once the stabilizer has been carefully aligned,
use a felt-tipped pen to trace the outline of the
fuselage onto the stabilizer.
32
6. Mark the stabilizer so you know which is top and
bottom. Remove the stabilizer and use a hobby
knife with a new blade to cut the covering 1/16"
(1.5mm) inside the lines drawn in the last step.
Note: Do not cut into the wood as it will
weaken the stabilizer. A soldering iron or hot
knife can be used instead of a hobby knife.
7. Slide the stabilizer partially into the fuselage.
Apply a thin layer of 6-minute epoxy onto the
exposed wood of the stabilizer, both top and
bottom. Slide the stabilizer into the fuselage and
clean up any excess epoxy using a paper towel
and rubbing alcohol.
33
8. Attaching the fin is basically the same as
installing the stabilizer, except for checking that
the fin is perpendicular to the stabilizer using
a square. Remember to mark and remove the
covering from the bottom of the fin before using
epoxy to secure it to the fuselage
Linkage Installation
Required Parts
• Fuselage • 4mm wheel collar (2)
• Clevis (3) • Clevis retainer (3)
• Tail wheel assembly • 1" (25mm) tail wheel
• 2mm wheel collar • 3mm setscrew
• 3mm x 6mm screw (2) • Pushrod wire keeper (2)
5
• 25
/
" (650mm) pushrod wire (3)
8
• Control horn w/backplate (3)
• 2mm x 12mm screw (6) • CA hinges (9)
Required Tools and Adhesives
• Phillips screwdriver • Felt-tipped pen
• 6-minute epoxy • Petroleum jelly
• Pliers • Side cutter
• Drill
• Drill bit: 5/64" (2mm), 3/32" (2.5mm)
Note: If you plan on installing floats
permanently to your J-3 Cub, you may skip
Steps 1 though 5, starting at Step 6. The tail
wheel can be left in position if you plan on
using both the landing gear and floats. Refer to
your float manual for proper installation.
34
1. Locate the tail wheel assembly and apply
petroleum jelly to the wire above and below
the nylon mount. This helps prevent epoxy from
binding the tail gear.
2. Use 6-minute epoxy to glue the nylon mount
into the fuselage.
35
3. Drill a 3/32" (2.5mm) hole into the rudder
1
1
/
" (27mm) up from the bottom of the rudder.
16
Verify this measurement by holding the rudder in
position against the fuselage.
4. Cut a slot from the hole to the bottom of the
rudder. The slot will house the nylon mount when
the rudder is installed.
36
5. Attach the tail wheel using the 2mm wheel collar
and the 3mm setscrew.
6. Slide a clevis retainer onto a clevis, then thread
the clevis onto a 25
Slide the pushrod wire into the opening as shown.
5
/
" (650mm) pushrod wire.
8
7. Place T-pins in three of the CA hinges. Slide the
hinges into the rudder, and then slide the rudder
into position. Use tape to hold the rudder in
position. DO NOT glue the hinges or tail wheel
until instructed to do so.
37
8. Remove the backplate from a control horn.
Snap the clevis onto the control horn, and
hold it against the rudder and mark the
location for the horn.
9. Remove the rudder and drill the two locations
using a 5/64" (2mm) drill. Mount the horn
using two 2mm x 12mm screws and the
control horn backplate.
10. Roughen the tail gear wire with sandpaper. Use
6-minute epoxy on the tail gear wire to glue
into the rudder.
38
11. Remove the T-pins from the hinges and use thin
CA to glue them in place. Allow the epoxy and
CA to cure before continuing to the next step.
12. Snap the clevis onto the control horn and use
tape to hold the rudder centered. Mark the
pushrod where it crosses the servo horn using a
felt-tipped pen.
Note: Ensure the radio is turned on with
the trims and sub-trims centered and the
servos are centered.
39
13. Bend the wire at the mark. Drill a 5/64"
(2mm) hole in the servo arm and secure
the pushrod wire using a pushrod wire
keeper. Trim the rudder servo arm as shown
so it will not interfere with the operation of the
elevator servo.
Note: Trim the rudder servo arm as shown in
the photo.
14. Prepare three CA hinges using T-pins. Use
the hinges to temporarily attach an elevator
half to the stabilizer, using NO GLUE.
Prepare another pushrod, clevis, clevis
retainer and control horn as was done for
the rudder. With the elevator at neutral,
mark the location for the control horn.
40
15. Drill the holes for the control horn in
the elevator. Attach the control horn using two
2mm x 12mm screws.
16. Position the elevator back onto the stabilizer
and use thin CA to glue the hinges.
17. Prepare two wheel collars by threading
3mm x 6mm screws into them. Slide the wheel
collars onto the elevator pushrod.
41
18. Center the elevator and mark the pushrod. Bend
the pushrod and attach it to the elevator servo
arm using a pushrod wire keeper. Trim the
elevator servo arm as shown in the photo.
Note: Ensure the radio is turned on with
the trims and sub-trims centered and the
servos are centered.
19. Repeat Step 14 through 16 to attach the
remaining elevator half. Pass the pushrod
through the wheel collars when installing
the pushrod.
Note: It may be necessary to trim the length of
the pushrod wire.
42
20. Use a ruler to make sure both elevator halves
are centered. Once centered, tighten the
screws in the wheel collars. Remember to use
threadlock on those screws.
Note: Once set, coat the wheel collars and wire
with 6-minute epoxy.
43
Final Assembly
Required Parts
• Fuselage • Wing
• Front windshield • Side window (right and left)
• Wing strut (right and left)
• 2mm x 10mm sheet metal screws (6)
Required Tools and Adhesives
• Phillips screwdriver • Hobby scissors
• Felt-tipped pen • Sandpaper
• Canopy glue • Masking tape
1. Place the front windshield onto the fuselage. Trace
around the windscreen using a felt-tipped pen.
2. Lightly sand the fuselage inside the line drawn
in the last step. Also sand the inside edge of the
windshield where it will attach to the fuselage.
Note: You can also remove a 1/8" (3mm)
strip of covering inside the line. The bare
wood will provide a better gluing surface than
the covering.
44
3. Apply a thin bead of canopy glue around the
outer edge of the front windshield. Position the
windshield on the fuselage and use tape to hold it
until the glue has cured.
4. Use hobby scissors to trim out the side windows.
Trim the windows so there is a 1/16" (1.5mm) lip
to glue the windows to the fuselage sides.
45
5. After sanding the edges of the windows, use
canopy glue to secure them to the inside of the
fuselage. Use tape to hold them in position until
the glue fully cures.
6. Attach the wing to the fuselage. Place the
struts so the arrow on the strut is facing up and
is pointing towards the front of the plane.
Secure the strut using three 2mm x 10mm sheet
metal screws.
7. Repeat Step 6 for the remaining wing strut.
46
Center of Gravity / Battery Installation
An important part of preparing the aircraft for
flight is properly balancing the model.
Caution: Do not inadvertently skip this step!
The recommended Center of Gravity (CG) location
for the J-3 Cub is 2
edge. The range for the Center of Gravity is
1
/
"–2
2
3
/
" (63mm–70mm) behind the leading edge.
4
2
5
/
" (66mm) back from the leading
8
47
Control Throws
Exponential Settings
The amount of control throw should be adjusted as closely
as possible using mechanical means, rather than making
large changes electronically at the radio. By moving the
position of the clevis at the control horn toward the outermost
hole, you will decrease the amount of control throw of the
control surface. Moving it toward the control surface will
increase the amount of throw. Moving the pushrod wire
at the servo arm will have the opposite effect: Moving it
closer to center will decrease throw, and away from center
will increase throw. Work with a combination of the two
to achieve the closest or exact control throws listed.
High Rate Low Rate
Aileron 3/4" up, 3/4" down 1/2" up, 1/2" down
Elevator 5/8" up, 5/8" down 3/8" up, 3/8" down
Rudder 1
3
/
" right, 1
8
3
/
" left 1" right, 1" right
8
Note: The above throws are a good starting
point for most flight conditions.
High Rate Low Rate
Aileron 20% 10%
Elevator 20% 10%
Rudder 20% 10%
Once the control throws have been set, slide the clevis
retainers onto the clevises to secure their positions.
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Flying Notes
Flying the J-3 Cub is a pleasure. Takeoffs are easy as well as
landings. Loops and rolls are as easy as pushing the control
stick in the desired direction with the control throws listed in
the manual. Flight times of 17 minutes with the recommended
Li-Po battery are common with landing gear, and 15 minutes
when equipped with floats. Using the Ni-MH battery option
will provide shorter flight times of 9 minutes but at a very
reduced battery cost. Float flying with the Ni-MH pack
should be limited to areas where there are no obstructions
around the lake. Climb out performance is increased with
the Li-Po power system over the Ni-MH power system.
When flying from floats there are a few flight parameters
to be aware of. Because of the inertia generated below
the centerline, the aircraft can depart during certain
harsh maneuvers. Whenever the aircraft is put into a
very steep bank angle (70–80 degrees) and you pull
hard on the elevator, the aircraft will snap to the left. If
you are in a right-hand turn it will snap out of the turn
and to the left. If you are in a left-hand turn, it will tuck
even tighter into the turn. During taxiing on floats, it is
recommended to hold full up elevator to minimize the
amount of splash from the floats. During takeoff, hold
half up elevator as you accelerate to minimize the splash
and to keep the floats from digging into the water. We
recommend low rate rudder for takeoff when using floats.
49
2006 Official AMA National Model Aircraft Safety Code
GENERAL
1) I will not fly my model aircraft in sanctioned events,
air shows or model flying demonstrations until it
has been proven to be airworthy by having been
previously, successfully flight tested.
2) I will not fly my model higher than approximately
400 feet within 3 miles of an airport without notifying
the airport operator. I will give right-of-way and avoid
flying in the proximity of full-scale aircraft. Where
necessary, an observer shall be utilized to supervise
flying to avoid having models fly in the proximity of
full-scale aircraft.
3) Where established, I will abide by the safety rules
for the flying site I use, and I will not willfully or
deliberately fly my models in a careless, reckless and/
or dangerous manner.
4) The maximum takeoff weight of a model is 55
pounds, except models flown under Experimental
Aircraft rules.
5) I will not fly my model unless it is identified with
my name and address or AMA number on or in the
model. (This does not apply to models while being
flown indoors.)
6) I will not operate models with metal-bladed
propellers or with gaseous boosts, in which gases
other than air enter their internal combustion
engine(s); nor will I operate models with extremely
hazardous fuels such as those containing
tetranitromethane or hydrazine.
RADIO CONTROL
1) I will have completed a successful radio equipment
ground range check before the first flight of a new or
repaired model.
2) I will not fly my model aircraft in the presence
of spectators until I become a qualified flier, unless
assisted by an experienced helper.
50
2006 Official AMA National Model Aircraft Safety Code
3) At all flying sites a straight or curved line(s) must
be established in front of which all flying takes place
with the other side for spectators. Only personnel
involved with flying the aircraft are allowed at or in
front of the flight line. Intentional flying behind the
flight line is prohibited.
4) I will operate my model using only radio control
frequencies currently allowed by the Federal
Communications Commission. (Only properly licensed
Amateurs are authorized to operate equipment on
Amateur Band frequencies.)
5) Flying sites separated by three miles or more
are considered safe from site-to-site interference,
even when both sites use the same frequencies. Any
circumstances under three miles separation require a
frequency management arrangement, which may be
either an allocation of specific frequencies for each site
or testing to determine that freedom from interference
exists. Allocation plans or interference test reports shall
be signed by the parties involved and provided to
AMA Headquarters.
Documents of agreement and reports may exist
between (1) two or more AMA Chartered Clubs,
(2) AMA clubs and individual AMA members not
associated with AMA Clubs, or (3) two or more
individual AMA members.
6) For Combat, distance between combat engagement
line and spectator line will be 500 feet per cubic inch
of engine displacement. (Example: .40 engine = 200
feet.); electric motors will be based on equivalent
combustion engine size. Additional safety requirements
will be per the RC Combat section of the current
Competition Regulations.
7) At air shows or model flying demonstrations, a
single straight line must be established, one side of
which is for flying, with the other side for spectators.
8) With the exception of events flown under AMA
Competition rules, after launch, except for pilots or
helpers being used, no powered model may be flown
closer than 25 feet to any person.
9) Under no circumstances may a pilot or other person
touch a powered model in flight.
51
8629
© 2006 Horizon Hobby, Inc.
4105 Fieldstone Road
Champaign, Illinois 61822
(877) 504-0233
www.horizonhobby.com
www.E-fliteRC.com
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