E-FLITE J-3 Cub 25 ARF User manual

J-3 Cub 25 ARF
Assembly Manual

2
Introduction
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.
Table of Contents
Introduction................................................................2
Contents of Kit/Parts Layout .........................................3
Specifications.............................................................3
Covering Colors .........................................................3
Required Electronics & Accessories ...............................4
Outrunner (Direct Drive) Motor Setup ............................4
Required Tools and Adhesives ......................................4
Optional Accessories ..................................................5
Warning....................................................................5
Before Starting Assembly .............................................5
Note on Lithium Polymer Batteries.................................5
Using the Manual .......................................................5
Limited Warranty Period ..............................................5
Landing Gear Installation.............................................8
Motor and Cowling Installation ..................................12
Radio Installation ......................................................16
Wing Assembly ........................................................18
Tail Installation..........................................................30
Linkage Installation....................................................34
Final Assembly .........................................................44
Center of Gravity / Battery Installation........................47
Control Throws .........................................................48
Flying Notes.............................................................49
2006 Official AMA
National Model Aircraft Safety Code................50

3
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
Covering Colors
Cub Yellow HANU884
Black HANU874
Contents of Kit/Parts Layout
Specifications
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)

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Required Electronics & Accessories
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
Required Tools and Adhesives
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

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Optional Accessories
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.
Note on Lithium Polymer Batteries
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.

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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.
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.

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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 [e-mail], 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.

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)
• 2 1/2" (63mm) foam wheel (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.
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
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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.
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3. Press the 2 1/2" (63mm) foam wheel onto
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.
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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.
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1. Prepare the outrunner motor by attaching the
X-mount to the motor using screws supplied with
the motor.
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.
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2. Attach the motor to the firewall using four
6-32 x 1/2" socket head screws included with
the J-3 Cub.
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.
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: Ensure you mount the speed control with
the label towards the fuselage sidewall. This
will assure maximum cooling for the speed
control.
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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 counter-
clockwise 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.
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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.
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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.
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.
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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.
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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.
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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.
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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.
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.
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: Do not use accelerator in the hinging
process. The CA must be allowed to soak into
each hinge naturally.
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