Horizon Hobby UMX B-25 Mitchell User manual

UMX™B-25 Mitchell
Instruction Manual
Bedienungsanleitung
Manuel d’utilisation
Manuale di Istruzioni

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WARNING: Read the ENTIRE instruction manual to become familiar with the features of the
product before operating. Failure to operate the product correctly can result in damage to the product,
personal property and cause serious injury.
This is a sophisticated hobby product. 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. Do not use with incompatible components or alter this product
in any way outside of the instructions provided by Horizon Hobby, LLC. This 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
serious injury.
Safety Precautions and Warnings
• Always keep a safe distance in all directions
around your model to avoid collisions or injury.
This model is controlled by a radio signal subject
to interference from many sources outside your
control. Interference can cause momentary loss
of control.
• Always operate your model in open spaces away
from full-size vehicles, traffic and people.
• Always carefully follow the directions and
warnings for this and any optional support equip-
ment (chargers, rechargeable battery packs, etc.).
• Always keep all chemicals, small parts and
anything electrical out of the reach of children.
• Always avoid water exposure to all equipment
not specifically designed and protected for this
purpose. Moisture causes damage to electronics.
• Never place any portion of the model in your
mouth as it could cause serious injury or
even death.
• Never operate your model with low transmitter
batteries.
• Always keep aircraft in sight and under control.
• Always use fully charged batteries.
• Always keep the transmitter powered on while
aircraft is powered.
• Always remove batteries before disassembly.
• Always keep moving parts clean.
• Always keep parts dry.
• Always let parts cool after use before touching.
• Always remove batteries after use.
• Always ensure failsafe is properly set
before flying.
• Never operate aircraft with damaged wiring.
• Never touch moving parts.
Age Recommendation: Not for children under 14 years. This is not a toy.
NOTICE
All instructions, warranties and other collateral documents are subject to change at the sole discretion
of Horizon Hobby, LLC. For up-to-date product literature, visit www.horizonhobby.com and click on the
support tab for this product.
Meaning of Special Language:
The following terms are used throughout the product literature to indicate various levels of potential
harm when operating this product:
NOTICE: Procedures, which if not properly followed, create a possibility of physical property damage
AND little or no possibility of injury.
CAUTION: Procedures, which if not properly followed, create the probability of physical property
damage AND a possibility of serious injury.
WARNING: Procedures, which if not properly followed, create the probability of property damage,
collateral damage, and serious injury OR create a high probability of superficial injury.

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To register your product online, go to www.e-fliterc.com
Installed
Motor: 8.5mm Brushed Motor
Receiver : DSM2/DSMX 6 Ch Ultra Micro
AS3X®Receiver/ESC
(2) 2.3-Gram Performance Linear Long
Throw offset Servos
Needed to Complete
Recommended Battery: 300mAh 1S
3.7V 25C Li-Po
Recommended Battery Charger:
(DC) Celectra™1S 3.7 Variable Rate DC
Li-Po Charger
(USB) 300mAh 1S 3.7V 25C Li-Po,
26AWG with 1S to USB Charger Adapter
Recommended Transmitter:
Spektrum™DSM2®/DSMX®full range
with dual-rates (DXe or DX4e and up)
17.17 in (436mm)
21.65 in (550mm)
3.30 oz
(93 g)
Transmitter and Receiver Binding...........................4
Low Voltage Cutoff (LVC)........................................4
ESC/Receiver Arming, Battery Installation
and Center of Gravity .............................................5
Control Direction Tests...........................................6
Control Centering...................................................7
Control Horn Settings.............................................7
Dual Rates.............................................................7
Landing Gear Installation .......................................8
Flying Tips and Repairs..........................................9
Post Flight Checklist ..............................................9
Power Components Service .................................10
Troubleshooting Guide .........................................11
Limited Warranty .................................................12
Warranty and Service Information........................14
IC Information......................................................14
FCC Information...................................................14
Compliance Information for the European Union...15
Replacement Parts ..............................................55
Optional Parts......................................................56
Decal Application.................................................57
Table of Contents
Specifications
Preflight Checklist
Wing Area: 63.80 sq in
(4.1 sq dm)

1. Charge flight battery.
2. Install flight battery in aircraft (once it
has been fully charged).
3. Bind aircraft to transmitter.
4. Make sure linkages move freely.
5. Perform Control Direction Test with
transmitter.
6. Perform AS3X Control Direction Test with
aircraft.

7. Set dual rates.
8. Adjust center of gravity.
9. Perform a radio system Range Check.
10. Find a safe and open area.
11. Plan flight for flying field conditions.
12. Set flight timer for 4 minutes for first
flight.

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Binding is the process of programming the receiver to recognize the GUID (Globally Unique Identifier)
code of a single specific transmitter. You need to ‘bind’ your chosen Spektrum™DSM2/DSMX technology
equipped aircraft transmitter to the receiver for proper operation.
Any full range Spektrum DSM2/DSMX transmitter can bind to the DSM2/DSMX receiver. Please visit www.
bindnfly.com for a complete list of compatible transmitters.
Transmitter and Receiver Binding
Binding Procedure
CAUTION: When using a Futaba transmitter with a Spektrum DSM®module, you must reverse the
throttle channel and rebind. Refer to your Spektrum module manual for binding and failsafe instructions.
Refer to your Futaba transmitter manual for instructions on reversing the throttle channel.
1. Refer to your transmitter’s unique instructions for binding to a receiver (location of transmitter’s
Bind control).
2. Make sure the flight battery is disconnected from the aircraft.
3. Power off your transmitter.
4. Connect the flight battery in the aircraft. The receiver LED will begin to flash rapidly (typically after
5 seconds).
5. Make sure the transmitter controls are neutral and the throttle and throttle trim are in low position.
6. Put your transmitter into bind mode. Refer to your transmitter’s manual for binding button or
switch instructions.
7. After 5 to 10 seconds, the receiver status LED will turn solid, indicating that the receiver is bound
to the transmitter. If the LED does not turn solid, refer to the Troubleshooting Guide at the back of
the manual.
When a Li-Po battery is discharged below 3V per
cell, it will not hold a charge. The aircraft’s ESC
protects the flight battery from over-discharge
using Low Voltage Cutoff (LVC). Once the battery
discharges to 3V per cell, the LVC will reduce the
power to the motor in order to leave adequate
power to the receiver and servos to land the
airplane.
When the motor power decreases, land the aircraft
immediately and replace or recharge the flight
battery.
Always disconnect and remove the Li-Po battery
from the aircraft after each flight. Charge your Li-Po
battery to about half capacity before storage. Make
sure the battery charge does not fall below 3V per
cell. Failure to unplug a connected battery will result
in trickle discharge.
For your first flights, set your transmitter timer
or a stopwatch to 4 minutes. Adjust your timer for
longer or shorter flights once you have flown the
model.
NOTICE: Repeated flying to LVC will damage the
battery.
Low Voltage Cutoff (LVC)
For subsequent flights, power ON the transmitter for 5 seconds before connecting the flight battery.

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1-2-3-4-5 Sec.
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ESC/Receiver Arming, Battery Installation and Center of Gravity
CAUTION: Always keep hands away from the
propeller. When armed, the motor will turn the
propeller in response to any throttle movement.
Arming the ESC/receiver occurs after binding, but
subsequent connection of a flight battery requires
the following steps.
AS3X
The AS3X®system will not activate until the
throttle stick is increased for the first time. Once
active, the control surfaces may move rapidly
and noisily on the aircraft. This is normal. AS3X
technology will remain active until the battery is
disconnected.
1. Remove the battery hatch from the fuselage.
2. Attach the battery to the hook and loop strip so
the battery is centered on the battery tray.
Center of Gravity (CG)
Measure back 35mm from the leading edge of the
wing, where the wing meets the fuselage and place
a mark. Balance the airplane on this CG mark with
all landing gear installed.
3. Lower the throttle and throttle trim to the
lowest settings on your transmitter. Power
on your transmitter, then wait 5 seconds.
4. Connect the battery to the ESC, noting proper
polarity. Keep the plane immobile and away
from wind for 5 seconds to allow the AS3X
system to initialize. A series of tones and
a continuous LED indicates a successful
connection.
CAUTION: Always disconnect the Li-Po
battery from the ESC when not flying to eliminate
power supplied to the motor. The ESC does not have
an arming switch and will respond to any
transmitter input when a signal is present.
CAUTION: Always disconnect the Li-Po
battery from the ESC when not flying to avoid
over-discharging the battery. Batteries discharged
to a voltage lower than the lowest approved voltage
may become damaged, resulting in loss of
performance and potential fire when batteries
are charged.
35mm

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Aircraft
movement AS3X Reaction
1. Advance the throttle above
25% to activate the AS3X
system.
2. Fully lower the throttle.
3. Move the entire aircraft
as shown and ensure the
control surfaces move in
the direction indicated in
the graphic. If the control
surfaces do not respond as
shown, do not fly the aircraft.
Refer to the receiver manual
for more information.
Once the AS3X system is active,
control surfaces may move
rapidly. This is normal. AS3X
is active until the battery is
disconnected.
ElevatorAileronRudder
AS3X®Control Direction Test
This test ensures that the AS3X®control system is functioning properly.
Control Direction Tests
Traditional Control Direction Test
You should bind your aircraft and transmitter before doing these tests.
Move the controls on the transmitter to make sure the aircraft control surfaces move correctly and in the
proper direction. Make sure the tail linkages move freely and that paint or decals are not adhered to them.

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Before the first flight, or in the event of an
accident, make sure the flight control surfaces
are centered. Adjust the linkages mechanically if
the control surfaces are not centered. Use of the
transmitter sub-trims may not correctly center the
aircraft control surfaces due to the mechanical
limits of linear servos.
1. Make sure the control surfaces are neutral
when the transmitter controls and trims are
centered. The transmitter sub-trim must
always be set to zero.
2. When needed, use a pair of pliers to carefully
bend the metal linkage (see illustration).
3. Make the U-shape narrower to make the
connector shorter. Make the U-shape wider
to make the linkage longer.
Centering Controls After First Flight
For best performance with AS3X, it is important
that excessive trim is not used. If the aircraft
requires excessive transmitter trim (4 or more clicks
of trim per channel), return the transmitter trim to
zero and adjust the linkages mechanically so that
the control surfaces are in the flight
trimmed position.
Control Horn Settings
The table to the right shows the factory settings for
the control horns. Fly the aircraft at factory settings.
CAUTION: When these are incorrectly
connected for the pilot’s skill level, unexpected
aircraft response to controls can result. This can
cause damage to the aircraft and personal injury.
Elevator
Dual Rates
To obtain the best flight performance, we
recommend using a DSM2/DSMX radio capable
of adjustable Dual Rates. The suggested settings
shown here are the recommended starting settings.
Adjust according to the individual preferences after
the initial flight.
NOTICE: Do not set your transmitter travel adjust
over 100%. If the TRAVEL ADJUST is set over
100%, it will not result in more control movement, it
will overdrive the servo and cause damage.
It is normal for linear servos to make significant
noise. The noise is not an indication of a faulty
servo.
Tip: For the first flight, fly the model in low rate.
Dual Rate
High Low
Aileron 100% 70%
Elevator 100% 70%
Rudder 100% 70%
Control Centering
Rudder

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Landing Gear Installation
1. Carefully slide the landing gear into the plastic
mounts on the bottom of the fuselage.
When needed, disassemble in reverse order.

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We recommend flying your aircraft outside in calm
conditions. Always avoid flying near houses, trees,
wires and buildings. You should also be careful to
avoid flying in areas where there are many people,
such as busy parks, schoolyards or soccer fields.
Consult local laws and ordinances before choosing
a location to fly your aircraft.
Takeoff
Place the aircraft in position for takeoff (facing into
the wind if flying outdoors). Set dual rates to low
position and gradually increase the throttle to ¾ to
full and steer with the rudder. Pull back gently on
the elevator and climb to check trim. Once the trim
is adjusted, begin exploring the flight envelope of
the aircraft.
Landing
Land into the wind. Fly the aircraft to approximately
6 inches (15cm) or less above the runway, using a
small amount of throttle for the entire descent. Keep
the throttle on until the aircraft is ready to flare.
During flare, keep the wings level and the airplane
pointed into the wind. Gently lower the throttle while
pulling back on the elevator to bring the aircraft
down on all three wheels.
Failure to lower the throttle
stick and trim to the lowest
possible positions during a
crash could result in damage
to the ESC in the receiver
unit, which may require
replacement.
Over Current Protection
(OCP)
This aircraft is equipped with
Over Current Protection (OCP).
This feature protects the
ESC from overheating. OCP
stops the motor when the
transmitter throttle is set too high and the propeller
cannot turn. The OCP will only activate when the
throttle stick is positioned just above 1/2 throttle.
After the ESC stops the motor, fully lower the
throttle to re-arm the ESC.
NOTICE: Crash damage is not covered under the
warranty.
Repairs
Repair the aircraft using foam-compatible CA
(cyanoacrylate adhesive) or clear tape. Only use
foam-compatible CA, as other types of glue can
damage the foam. When parts are not repairable,
see the Replacement Parts List for ordering by
item number.
For a listing of all replacement and optional parts,
refer to the list at the end of this manual.
NOTICE: Use of foam-compatible CA accelerant on
your aircraft can damage paint. DO NOT handle the
aircraft until the accelerant fully dries.
NOTICE: When you are finished flying, never leave
the aircraft in direct sunlight or in a hot, enclosed
area such as a car. Doing so can damage the foam.
Flying Tips and Repairs
Post Flight Checklist

1. Disconnect the flight battery from the
ESC (Required for safety and battery
life).
2. Power OFF the transmitter.
3. Remove the flight battery from the
aircraft.

4. Recharge the flight battery.
5. Store the flight battery apart from the
aircraft and monitor the battery charge.
6. Make note of the flight conditions and
flight plan results, planning for future
flights.
NOTICE:
Always decrease
throttle at propeller
strike.

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Power Components Service
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CAUTION: DO NOT handle propeller parts
while the flight battery is connected. Personal
injury could result.
Disassembly
1. Disconnect the battery from the
ESC/receiver.
2. Carefully cut at the seam on each nacelle and
remove the bottom half.
3. Hold the prop shaft using needle-nose
pliers or hemostats.
4. Turn the propellers counterclockwise (facing
the front of the model) to remove. Turn the
propeller clockwise to install.
5. Hold the nut (A) on the end of the prop
shaft using needle-nose pliers or
hemostats.
6. Turn the gear on the shaft to remove the nut.
7. Gently pull the shaft (B) from the gearbox (C)
and make sure the washer (D) and two
bushings (E) are not lost.
8. Disconnect the motor from the ESC/
receiver.
9. Gently push the motor out of the
gearbox and remove the motor
through the bottom of the nacelle.
NOTICE: DO NOT remove the gearbox from
the aircraft. Damage to the aircraft will result.
Assembly
Assemble the aircraft using the instructions
above in reverse order.
• Correctly align the prop shaft gear with the
pinion gear on the motor.
• Connect the motor to the ESC/receiver so
that the powered motor turns the propeller
counterclockwise (facing the front of the model).
• Make sure the propeller size numbers (112 x 90)
face away from the motor (see illustration).
• Attach the spinner to the propeller using foam-
compatible CA (Cyanoacrylate adhesive).
• Assemble each nacelle into place and secure with
foam-compatible CA.
112 x 90
E
C
D
112 x 90
A
B