Horizon Hobby XF421EX User Manual

5-CHANNEL COMPUTER RADIO

3

XF421EX MANUAL • Table of Contents

I. INTRODUCTION

1. Using This Manual 4

2. Features 4

2.1 Transmitter Features 4

2.2 Receiver Features 4

2.3 Servo Features 5

2.4 Servo Layout 5

3. Specifications 6

3.1 System Specifications 6

3.2 Transmitter Specifications 6

3.3 Servo Specifications 6

3.4 Receiver Specifications 7

3.5 Charger Specifications 7

3.6 Airborne Battery Pack 7

4. Battery Charging 8

4.1 Transmitter/Receiver 8

4.2 Charger 8

5. Trainer System 9

II. XF421EX MANUAL

1. Transmitter Controls 10

1.1 Control Identification and Location 10

1.2

Receiver Channel Assignment/
Transmitter Throttle ALT

10

1.3 Transmitter Rear 11

1.4 Control Stick Length Adjustment 11

1.5 Direct Servo Control (DSC) 12

1.6 Neck Strap Attachment 12

2. Connections 13

2.1 Installation Requirements 13

2.2 Connections 13

3. Key Input and Display 14

4. Battery Alarm and Display 14

5. Input Mode and Functions 15

5.1 Normal Display 15

5.2 Mode Types 15

5.3 System Mode 16

5.4 Function Mode 16

6. Functions (System Mode) 17

6.1 Data Reset 17

6.2 Model Selection 18

6.3 Wing Type Selection 19

6.4 Model Name Entry 21

7. Functions (Function Mode) 22

7.1 Servo Reversing 22

7.2 Sub-Trim 23

7.3 Travel Adjustment 24

8. Data Sheet 25

III.IMPORTANT INFORMATION

1. General Notes 26

2. Daily Flight Checks 26

3. Warranty Coverage 27

4. Repair Service Instructions 27

5. Frequency Chart 28

T ABLE OF CONTENTS

We strongly encourage all prospective and current R/C
aircraft pilots to join the Academy of Model Aeronautics.
The AMA is a non-profit organization that provides
services to model aircraft pilots. As an AMA member you
will receive a monthly magazine entitled Model Aviation, as
well as a liability insurance plan to cover against possible
accident or injury. All AMA charter aircraft clubs require

individuals to hold a current AMA membership prior to
operation of their models. For further information you can
contact the AMA at:

Academy of Model Aeronautics
5151 East Memorial Drive
Muncie, IN 47302
[phone]

Thank you for purchasing the JR XF421EX 5-Channel Radio
System. This unit has been designed to provide the
modeler with a high quality, user friendly radio system
that can be depended upon for years to come.

It’s important that you carefully read this manual before
attempting to operate your system. Please pay particular
attention to Page 9, Introduction 4.2 Charging Your
XF421EX Radio System.

AMA INFORMA TION

INTRODUCTION TO THE XF421EX RADIO SYSTEM

4

XF421EX MANUAL • INTRODUCTION 1: Using This Manual / INTRODUCTION 2: Features

The XF421EX is a full feature introductory computer
radio that can be used for airplanes.
A blank data sheet is included at the end of this
manual. Once you have input all the necessary data
into your transmitter for a particular model, we

strongly recommend that you write that information
down on a copy of the data sheet provided. This is to
insure that, in the rare case of a memory failure, you
will not lose your data.

INTRODUCTION 1:Using This Manual

USING THIS MANUAL

1

•

Easy-to-read LCD screen

•

2 model memory

•

Trainer system compatible with most other JR
radios

•

2 conveniently mounted programming switches

•

Computer designed ergonomically styled case

•

Adjustable stick length

•

Throttle trim only affects idle position

•

Two speed scrolling—Press and hold the
appropriate button to scroll quickly or press and
release to scroll in steps

•

Flaperons mixing

•

Delta wing mixing

•

V-tail mixing

R600 Receiver

•

The R600’s extremely compact size allows it to fit
easily in limited spaces.

•

An independent laboratory ranked the R600
receiver with JR’s patented ABC&W circuitry as
one of the best receivers ever tested in terms of
3IM, 2IM, adjacent channel rejection, signal-to­noise ratio, and on-channel capture point.

•

A special “unwanted interference limiter” ignores
signals outside of the R600’s band width when
the receiver is on and the transmitter is off. The

limiter also prevents servos from random
glitching when other transmitters are operating
in close proximity.

•

The electrical circuitry in the R600 is state-of-the­art surface mount technology (SMT). These SMT
components draw less current, thus increasing
flying time. Flush mounting of these components
also reduces the risk of vibration wear and
damage.

•

The R600 is compatible with all JR FM­transmitting radios.

TRANSMITTER FEA TURES

2.1

RECEIVER FEA TURES

2.2

INTRODUCTION 2:Features

5

XF421EX MANUAL • INTRODUCTION 2: Features

INTRODUCTION 2:Features continued

517 Servo

•

A .03ms deadband amplifier insures accurate
neutral centering.

•

Low current drain.

•

Ball bearing supported ouput shaft

•

An indirect drive feedback potentiometer gives
additional protection from vibration.

SERVO FEA TURES2.3

SERVO LAYOUT

2.4

Servo Mounting Flange

Rubber Grommets

Rubber Grommets

Servo Case

Servo Lead w/Connector

Servo Output Shaft

Servo Mounting Flange

Servo Arm/Horn

Servo Arm Retaining Screw

Servo Eyelet

Top View

6

XF421EX MANUAL • INTRODUCTION 3: Specifications

INTRODUCTION 3:Specifications

SYSTEM SPECIFICA TIONS

TRANSMITTER SPECIFICA TIONS

3.1

3.2

SYSTEM NAME XF421EX
TRANSMITTER BODY XF421EX
RECEIVER R600
CHARGER NEC-221
AIRBORNE BATTERY 4N-600
SERVOS NES-517BBX4
ACCESSORIES Mini Switch

12" Aileron Extension
Servo Accessories
Instruction Manual

TYPE AIRPLANE

MODEL NUMBER XF421EX
ENCODER 5 Channel Computer System
RF 50/53/72 MHz
MODULATION PPM (FM)
OUTPUT POWER Approximately 1 Watt
CURRENT DRAIN 200mA
POWER SOURCE 1.2Vx8 Nicad (9.6V) 600mah
OUTPUT PULSE 1000-2000 (1500 Neutral)

TYPE AIRPLANE

SERVO SPECIFICA TIONS3.3

TORQUE (oz./in.) 40.3
SPEED (sec.) .25
WEIGHT (oz.) 1.47
SIZE (in.) (W x L x H) 0.73 x 1.52 x 1.32
BB YES
MOTOR 3-Pole Ferite

TYPE 517BB

7

XF421EX MANUAL • INTRODUCTION 3: Specifications

RECEIVER SPECIFICA TIONS

3.4

CHARGER SPECIFICA TIONS

AIRBORNE BA TTERY P ACK

3.5

3.6

MODEL NUMBER NER-600
TYPE 6-Channel/FM-ABC & W/Circuitry
FREQUENCY 50/53/72MHz
SENSITIVITY (Microseconds) 5µs Minimum
SELECTIVITY 8KHz/50dB
WEIGHT (oz.) 1 oz.
SIZE (in.) (W x L x H) 1.43 x 2.06 x .55
RECEIVER ANTENNA 39" For All Aircraft Frequencies

TYPE R600 FM

MODEL NUMBER NEC-211
INPUT VOLTAGE AC 100-120V
OUTPUT CURRENT 50mAh Tx/50mAh Rx
CHARGING TIME 15 Hours

TYPE AIRPLANE

MODEL NUMBER 4N-600
VOLTAGE 4.8V
SIZE (in.) (W x L x H) 2.24 x 0.59 x 2.05
WEIGHT (oz.) 3.3

TYPE AIRPLANE

INTRODUCTION 3:Specifications continued

8

XF421EX MANUAL • INTRODUCTION 4: Battery Charging

INTRODUCTION 4:Battery Charging

The pilot lamps should always be on during the
charging operation. If they are not, check to make
sure you have turned off both the transmitter and
receiver.

Do not use the charger for equipment other than JR.
The charging plug polarity may not be the same and
equipment damage may result.

Do not use other manufacturers’ after-market
accessories that plug into the transmitter’s charging
jack. If you do, any damage that results will not be
covered by warranty. If you are unsure of
compatibilities with your radio, seek expert advice
before doing anything to avoid possible damage.
During the charging operation, the charger’s
temperature is slightly elevated. This is normal.

CHARGER4.2

It is imperative that you fully charge both the
transmitter and the receiver battery packs prior to
each day of flying. For the initial charge, leave the
charger and batteries hooked up for 20-24 hours in
order to fully charge both battery packs to peak
capacity. For subsequent charges, leave the charger
and batteries hooked up overnight (approximately
16 hours).

The charger supplied with this system is designed to
recharge your transmitter battery at a rate of 50mA.
The receiver battery pack will charge at 50mA for the
600mAh battery pack.

Transmitter Only

The center pin on all JR remote control systems is
negative. Therefore, the center pin on all JR
chargers is negative, not positive. This is different
from any other manufacturers’ chargers and radio
systems. Beware of improper connections based
on “color code” wire leads as they do not apply
in this instance. You must make certain that the
center pin of your JR transmitter is always
connected to the negative voltage for correct
polarity hookup.

TRANSMITTER / RECEIVER4.1

RIGHT SIDE OF TRANSMITTER

CENTER

PIN IS

NEGATIVE

OUTSIDE IS POSITIVE

CHARGER PIGTAIL FOR TRANSMITTER

BLACK TO POSITIVE

RED TO NEGATIVE

CHARGER PIGTAIL FOR RECEIVER

RED–POSITIVE / BROWN–NEGATIVE / ORANGE–SIGNAL

9

XF421EX MANUAL • INTRODUCTION 5: Trainer System

The XF421EX features a built-in trainer system. The
transmitter can be used as either a master (trainer) or
as a slave (trainee). The XF421EX is compatible with

all other current JR radios that have built-in trainer
systems. An optional trainer cord is needed
(JRPA130).

1. Match the servo reversing, sub-trims, travel
adjust and trims of both radios.

2. Plug the optional trainer cord into both
transmitters.

3. Turn on the master transmitter. (Note: The slave
radio must be left off.)

4. Test all the control functions on your aircraft with
the master radio.

5. Push the trainer button on the master transmitter
and check all the control functions with the slave
radio.

INTRODUCTION 5:TrainerSystem

TRAINER SYSTEM5

D.S.C.

TRAINER

CORD INPUT

Operating the T rainer System

TRAINER BUTTON

MULTI

TRAINER

DATA

ENTER

SCROLL

CHANNEL

FUNCTION 3-4 1-4 FUNCTION 1-2 2-3

DISPLAY

5 CHANNEL MULTI-DATA COMPUTER DISPLAY SYSTEM

VOLTAGE
INDICATOR

AUX.CH.

ENTER

+ INCR

- DECR

ON

OPTIONAL

TRAINER CORD

(JRPA130)

MULTI

TRAINER

DATA

ENTER

SCROLL

CHANNEL

FUNCTION 3-4 1-4 FUNCTION 1-2 2-3

DISPLAY

5 CHANNEL MULTI-DATA COMPUTER DISPLAY SYSTEM

VOLTAGE
INDICATOR

AUX.CH.

ENTER

+ INCR

- DECR

ON

MASTER TX

POWER SWITCH ON

SLAVE TX

POWER SWITCH OFF

10

XF421EX MANUAL • CHAPTER 1: Transmitter Controls

1. THRO Throttle Channel

2. AILE Aileron Channel

3. ELEV Elevator Channel

4. RUDDRudder Channel

5. GEAR Gear Channel

Transmitter Throttle ALT

The throttle ALT function makes the throttle stick
trim active only when the throttle stick is less than
half throttle. This gives easy, accurate idle
adjustments without affecting the high throttle
position.

RECEIVER CHANNEL ASSIGNMENT/TRANSMITTER THROTTLE AL T1.2

GEAR SWITCH

INPUT KEY

ANTENNA

LCD SCREEN

TRAINER SWITCH

INPUT KEY

AILERON/ELEVATOR STICK

THROTTLE/RUDDER STICK

POWER SWITCH

AILERON TRIM

ELEVATOR TRIM

THROTTLE TRIM

RUDDER TRIM

NECK STRAP EYELET

CARRYING HANDLE

CONTROL IDENTIFICA TION AND LOCA TION• Mode II

CHAPTER 1:Transmitter Controls

1.1