GRAUPNER MC-20 HoTT Owner's manual

33020.mc-20 HoTT.2.en
Programming Manual
o
Pro
Pro
mc-20
mc-20

2Table of contents
Code lock ...................................................... 31
Secret mode.................................................. 32
Display contrast........................................ 32
Language selection
Voice update............................................. 32
Change of display language..................... 33
Firmware update via SD card................... 36
Joystick calibration ................................... 36
Telemetry data display................................... 36
Commissioning the transmitter................................ 42
Firmware update via PC..................................... 43
Commissioning the receiver .................................... 46
Receiver system power supply........................... 47
General charging notices ................................... 49
Firmware update ................................................ 50
Installation notices................................................... 52
Term definitions ....................................................... 54
Assigning transmitter controls, switches
and control switches ................................................ 56
Digital trim ............................................................... 58
Winged models........................................................ 60
Receiver layout................................................... 61
Helicopter models.................................................... 64
Receiver layout................................................... 65
Program descriptions
Loading a new memory location.............................. 66
»Model select«....................................................... 69
»Copy / Erase«....................................................... 70
Erase model ....................................................... 70
Copy model ¼Model......................................... 70
Export to SD card............................................... 71
Import from SD card........................................... 72
Copy flight phase................................................ 72
Changes ............................................................. 73
»Suppress codes«................................................. 74
»Suppress models«............................................... 75
»Basic settings, model«
Winged model .................................................... 76
Binding receivers........................................... 77
General notices
Table of contents ....................................................... 2
Environmental protection notices .............................. 3
Safety notices ............................................................ 4
Safety notices and handling regulations for
Lithium-Ion (LiIo) and Lithium-Polymer
(LiPo) batteries .......................................................... 7
Foreword.................................................................. 10
Remote control set description................................ 11
Technical data.......................................................... 14
General operating notices
Transmitter..........................................................16
Opening the transmitter housing ...................16
Transmitter power supply...............................16
Recommended chargers...............................17
Battery operation timer in display.................. 18
Lithium battery, CR 2032............................... 18
Joystick length adjustment ............................18
Joystick conversions......................................19
Holder bracket for transmitter straps ............. 20
Installing additional controls, switches, etc.... 20
Aligning the antenna...................................... 20
Transmitter description
Front side.......................................................21
Face-side connectors
Charger socket......................................... 22
DSC (Direct Servo Control)...................... 22
mini-USB connector ................................. 23
Data socket .............................................. 23
Card slot (data storage) ........................... 23
Headset connector ................................... 24
ext. PPM................................................... 25
SPI ........................................................... 25
Inside the transmitter..................................... 26
Display and key pads .................................... 28
Operating the "data terminal" ........................ 29
Shortcuts ....................................................... 30
Warnings in the display ................................. 30
Function fields in the display ......................... 31
Table of contents
Range test..................................................... 80
Helicopter model ................................................ 84
Binding receivers........................................... 85
Range test..................................................... 88
»Model type«.......................................................... 94
»Helicopter type«................................................... 98
»Servo adjustment« ............................................ 102
»Stick mode«
Winged model .................................................. 104
Helicopter model .............................................. 106
»Control adjust«
Winged model .................................................. 108
Helicopter model .............................................. 112
Throttle limit function ................................... 117
Idle setting................................................... 117
Throttle limit in combination with AR
in the »Stick mode menu«......................... 119
»Dual Rate / Expo«
Winged model .................................................. 120
Helicopter model .............................................. 124
»Channel 1 curve«
Winged model .................................................. 128
Helicopter model .............................................. 131
»Switch display«.................................................. 134
»Control switch«.................................................. 135
»Logical switches«.............................................. 138
How do I program a flight phase?.......................... 140
»Phase settings«
Winged model .................................................. 142
Helicopter model .............................................. 146
»Phase assignment«........................................... 148
»Phase trim« (winged model)............................... 150
»Non-delayed channels«..................................... 151
»Timers (general)«............................................... 152
»Flight phase timers«.......................................... 156
What is a mixer...................................................... 159
»Wing mixers« ..................................................... 160
1 aileron............................................................163
1 aileron and 1 camber flap..............................164
2 ailerons..........................................................166

3
Table of contents
2/4 ailerons and 1/2/4 camber flaps .................168
»Helicopter mixer« .............................................. 176
Adjusting the throttle and pitch curve ............... 187
Autorotation setting........................................... 190
General remarks about freely progr. mixers .......... 192
»Free mixers« ...................................................... 193
Linear mixers.................................................... 197
Exponential mixers ........................................... 199
Examples.......................................................... 201
»MIX active/phase«.............................................. 204
»Mix only Channel«............................................. 205
»Dual mixer« ........................................................ 206
»Swashplate mixer« ............................................ 208
»Fail Safe«............................................................ 208
»Teacher/pupil« ................................................... 210
Connection schematic ...................................... 213
Wireless HoTT system ..................................... 214
»Transmitter output«........................................... 218
»Profi-trim«
Winged model .................................................. 220
Helicopter model .............................................. 222
»Trim memory«
Winged model .................................................. 224
Helicopter model .............................................. 226
»Telemetry«.......................................................... 228
Setting & dataview............................................ 229
Satellite mode of two receivers ................... 238
Sensor/s ...................................................... 239
Selecting sensor/s ............................................ 240
RF status view.................................................. 241
Select voice update .......................................... 242
»Channel sequence«........................................... 244
»Multichannel«..................................................... 246
»Ring Limiter«...................................................... 250
»MP3-Player« ....................................................... 254
»General basic settings« .................................... 256
»Servo display« ................................................... 262
»Servo test« ......................................................... 263
»Code lock« ......................................................... 264
»Info display«....................................................... 266
Environmental protection notices
The symbol on this product, its operating instructions
or packaging gives notice that this product may not
be discarded as common household waste at the end
of its service life. It must be turned over to a recycling
collection point for electric and electronic apparatus.
The materials can be recycled according to their
markings.You make an important contribution to
protection of the environment by utilizing facilities for
reuse, material recycling or other means of exploiting
obsolete equipment.
Batteries must be removed from the
unit and disposed of separately at an
appropriate collection point.
Please inquire with local authorities
about the responsible waste collection
locations.
This manual serves only as a source of information
and can be changed without prior notification.
Graupner accepts no responsibility or liability for
errors or inaccuracies which may be contained in
the information section of this manual.
Programming examples
Introduction............................................................ 268
Winged model
First steps......................................................... 270
Incorporating an electric drive .......................... 276
C1 joystick switchover between
Electric motor and butterfly.......................... 279
Electric motor and airbrake ......................... 282
Timer activation by control or switch................. 284
Parallel operating servos.................................. 286
Using flight phases
Example 1 ................................................... 288
Example 2 ................................................... 292
8-flap wings ...................................................... 298
Delta and flying wing models............................ 301
F3A model ........................................................ 304
Helicopter model.................................................... 308
Appendix
FCC declaration..................................................... 318
Conformity declaration........................................... 319
Guarantee certificate............................................. 320

4Safety notices
In order to enjoy your modeling hobby for a long time,
please read these instructions thoroughly and give
particular attention to the safety notices. You should
also register right away at https://www.graupner.de/
de/service/produktregistrierung.aspx since this is
the only way for you to automatically receive current
information about your product via email.
If you are a beginner with remote controlled model
aircraft, ships or cars, you should really ask an
experienced model pilot for assistance.
If this remote control system changes ownership,
these instructions should surely be included with
remote control system.
Intended usage
This remote control system may only be used for the
purpose intended by the manufacturer, i.e. for the
operation of unmanned remote controlled models.
Any other usage is not permissible.
Safety notices
SAFETY IS NO ACCIDENT
and
REMOTE CONTROLLED MODELS ARE NOT TOYS
… because even small models can cause substantial
property damage and/or personal injuries if they are
not handled properly - even if caused by third parties.
Technical defects of an electrical or mechanical
nature can lead to unexpected startup of a motor and/
or parts being hurled through the air to pose a danger
of injury to you and to others.
Short circuit conditions are to be avoided absolutely!
A short circuit condition may not only destroy parts
of the remote control system but, depending on
the circumstances and the battery energy involved,
may also pose acute danger of incineration or even
explosion.
All motor-driven parts, such as aircraft or ship
propellers, helicopter rotors, open gearboxes etc.
represent a constant danger. Contact with these parts
must be avoided. A rapidly turning aircraft propeller
can, for example, sever a finger. Also pay attention
that other objects do not come into contact with
driven parts.
When a drive battery is connected or a motor is
running: never get into the danger zone of driving
mechanisms.
Be sure to pay attention that motors do not start
up unintentionally while performing programming
operations. Disconnect the fuel supply or battery
terminals to motors before programming.
Protect all units from dust, dirt, moisture and other
foreign parts. Never expose these units to vibrations
or excessive hot or cold temperatures. Remote
control operation may only be performed under
"normal" outdoor temperatures, i.e. within a range of
-15°C to +55°C.
Avoid mechanical jarring and pressure stresses.
Always check units for damage to housings and
cables. Do not use units which have been damaged
or become wet, even after they are dry again.
Only those components and accessories which
we recommend may be used. Always use original
Graupner plug and jack connectors which are made
for one another out of the same materials.
When routing cables, pay attention that they are
not stressed, unduly kinked or broken. The sharp
edges of adjacent parts also represent a hazard for
insulated conductors.
Be sure that all plug and jack connections are firmly
seated. Do not pull on the cable to disconnect a
plugged connector.
No modifications whatsoever may be made to units.
Modifications will void the operating permit and all
insurance protection.
Installing the receiver
The receiver is to be installed with a cushion of foam
rubber to afford protection against jarring; in aircraft
models behind a strong rib, for a car or ship model
the location must be protected against dust and
spray water.
The receiver may not be mounted in direct contact
with the hull or chassis as this would allow motor
vibrations and/or roadway jarring to be transferred
directly to the receiver. When a receiver system is
installed in a model with a combustion motor, all
receiver parts should always be protected against the
intrusion of exhaust gases and oil residue. Above all,
this applies to the model's ON/OFF switch, which is
typically built into the model's outer surface.
Position the receiver such that connecting cables to
the servos and the power supply are routed with a
bit of slack and that the receiver's antenna is at least
5 cm away from any large metal parts or wiring except
for other receiver wires/cables. In addition to steel,
this also includes carbon fiber parts, servos, electric
motors, fuel pumps and all sorts of cables, etc.
Optimally the receiver should be placed at a readily
accessible location that is well away from all other
equipment. Under no circumstances may a servo
cable be wrapped around the antenna or routed close
to it.
Make sure that cables near the antenna cannot move
about during flight.
Routing the receiver's antenna
The receiver and its antennas must be positioned
as far away as possible from drives of any kind. If
the model's hull is made of carbon fiber material, the
ends of the antennas must extend outside of the hull.
The orientation of antennas is not critical.
Nevertheless, a vertical (upright) installation of receiver
antennas is advantageous. In the case of diversity
antennas (two antennas), the second antenna should
be oriented at a 90° angle to the first antenna.
Safety notices
Be sure to pay attention!

5
Safety notices
Pre-start checks
Before switching the receiver on, be sure the throttle
control is at its Stop/Idle position.
Always switch the transmitter on first
and then the receiver.
Always switch the receiver off first
and then the transmitter.
If this sequence is not maintained, such that the
receiver is still switched on when the corresponding
transmitter is switched to "OFF", then the receiver
may respond to other transmitters or general radio
frequency noise. This can cause the model to
execute uncontrolled operations that may cause
personal injuries and/or property damage.
In particular, for models equipped with a mechanical
gyro:
before switching off the receiver, disconnect the
model's power supply to prevent the motor from
revving up unintentionally.
The residual spin of a gyro often produces
so much voltage that the receiver may falsely
interpret a throttle signal! This will then cause the
motor to start up unexpectedly.
Range test
Perform checks for proper operation and range
before every session. Secure the model adequately
in place and ensure that no one is in front of the
model.
Perform a complete functional test on the ground
and execute a complete simulated flight to exclude
the possibility of system faults or problems with the
model's programming. When doing this, be sure to
follow the notices provided on pages 80 and 88.
Never operate the transmitter in Model mode, i.e.
for flying or driving, without an antenna. Be sure the
antenna is firmly seated in its socket.
Operating a winged aircraft, helicopter, ship or
car
Never fly over spectators or other pilots. Never
endanger humans or animals. Never fly in the vicinity
of high-voltage wires. Do not operate the model in the
vicinity of sluice locks or where real boats or ships
are operating. Do not operate a model on public
streets or highways, paths or plazas, etc.
Monitoring transmitter and receiver batteries
You must stop running the model to recharge
the transmitter's battery no later than when low
transmitter battery voltage triggers the "Batt must be
recharged!!" display and acoustic signal.
Check the charge in batteries routinely, particularly
the receiver's battery. Do not wait until the
movements of controlled mechanisms are noticeably
slower. Replace expended batteries before they
cause problems.
The battery manufacturer's charging instructions
are always to be followed, this includes mandatory
adherence to the length of charging time. Never leave
batteries being charged unattended.
Never attempt to charge primary batteries (non-
rechargeable batteries) because they can explode.
All secondary batteries (rechargeable batteries) must
be charged before every session. To avoid short
circuit conditions, first connect the charger cable's
banana plugs, polarity correct, into the charger and
thereafter connect the charger cable's plugs to the
transmitter and receiver batteries.
Disconnect all power sources from the model when it
is not to be used for an extended period of time.
Never attempt to use defective batteries, damaged
batteries or mixed-type battery combinations as
a single group. Do not use mixed combinations
of old and new batteries or batteries of different
manufacture.
Servo installation
Always mount servos with the provided rubber
vibration-damper parts. Only in this manner can these
parts be protected against excessively hard vibrations.
Installing control rods
Control rods must be installed such that they operate
freely and smoothly. It is particularly important that
all rudder levers are able to move to their full limits,
i.e. not otherwise mechanically blocked.
In order to be able to stop a running motor at any
time, control rods must be adjusted such that the
carburetor tap is completely closed when the joystick
and trim wheel are brought into their end idle position.
Pay attention that no metal parts, e.g. as a result of
rudder actuation, vibration, rotating parts, etc., rub
against one another. Metal-to-metal contact causes
electrical "noise" which can interfere with the correct
operation of the receiver.
Transmitter antenna orientation
Transmission field strength is minimal in an imaginary
line extending straight out from the end of the
transmitter's antenna. This means that "pointing"
the transmitter's antenna directly toward the model
will not produce good reception but rather degrade
reception.
When multiple remote controls are operating
simultaneously, pilots should position themselves in
a loose group. Pilots standing off to themselves not
only endanger their own models but those of others
as well.
However, when 2 or more pilots using 2.4 GHz
remote control systems are closer than 5 m to one
another this can lead to return channel overdrive
which, in turn, will trigger a range warning much too
early. Increase your distance between one another
until the range warning ceases.

6Safety notices
Capacity and operating time
The rule: "capacity is reduced with every successive
recharging", applies to all batteries. Internal resistance
increases at low temperatures to further reduce
capacity. As a consequence, the battery's ability to
provide current and hold its voltage is reduced.
Frequent charging or the use of battery maintenance
programs can also result in gradual loss of battery
capacity. Therefore the capacity of batteries should
be checked at regular intervals, not in excess of
every six months, and replaced if performance is
found to be significantly deficient.
Purchase only genuine Graupner batteries!
Interference suppression for electric motors
All conventional electric motors produce sparks
between their collector and brushes. Depending on
the type of motor involved, this may cause more or
less interference with the functionality of the remote
control system.
The electric motors of a properly built system should
therefore have interference suppression features.
For electric drive models it is particularly important
that every one of its motors is provided with proper
interference suppression. Interference filters
extensively suppress such disturbances and should
always be included.
Follow the respective recommendations included in
the motor's operating and installation notices.
For further details about interference filters, refer to
the Graupner RC main catalog or in Internet at
www.graupner.de.
Servo interference filters for extension cables
Order no. 1040
The servo interference filter is necessary when an
extended-length servo cable is used. This filter is
attached directly to the receiver output. In critical
cases a second filter can be attached to the servo.
Using electronic speed controllers
Choosing the right electronic controller is largely a
matter of matching controller performance to the
motor to be controlled.
In order to prevent an overload or damage to the
speed controller, its current rating should be at least
half of the maximum locked-rotor current draw of the
motor to which it is connected.
Particular attention is appropriate for so-called "tuning
motors". Because of their low-turns coils these
motors can draw a multiple of their rated current
in a locked-rotor condition and this can lead to the
destruction of the speed controller.
Electric ignition systems
Combustion motor ignition systems also produce
interference that can negatively influence remote
control functionality.
Always supply power to an electric ignition system
from a separate, dedicated battery.
Use only interference-suppressed spark plugs, spark
caps and shielded ignition leads.
Mount the receiver sufficiently far away from ignition
system components.
Static charges
A remote control system will be destroyed by the
magnetic shock waves produced by a lightning strike
- even if the storm is miles away. Therefore …
… stop flying right away if a storm is approaching.
Static charging via the antenna also represents a
lethal hazard.
Attention
In order to fulfill FCC HF emission requirements•
for mobile transmitters, a distance of at least
20 cm must be maintained between this system's
antenna and other persons when this system is
operating. Operation of this system at a lesser
distance is therefore not recommended.
To avoid disturbance caused by the electrical•
characteristics and emissions of other transmitters,
keep at least a 20 cm distance from other
transmitters.
Operation of the remote control system requires a•
correct program setting for the given country in the
Safety notices

7
Safety notices
transmitter unit. This is necessary for compliance
with diverse regulations like FCC, ETSI, CE etc.
Follow the respective instructions provided for this
with the transmitter and receiver.
Prior to every flight, perform a complete functional•
test, range test and execute a complete simulated
flight in order to exclude the possibility of system
faults or problems with the model's programming.
Never program the transmitter or receiver while•
the model is being operated.
Care and maintenance
Never clean the housing, antenna, etc. with cleaning
agents, gasoline, water or similar means. Use only a
dry, soft cloth.
Components and accessories
As manufacturer of this equipment Graupner GmbH &
Co. KG recommends only components and accessories
which have been tested and approved by Graupner
for their suitability, functionality and safety. If this
recommendation is followed, Graupner accepts
responsibility for the product.
Graupner cannot accept any responsibility for
the parts or accessories of other manufacturers
which have not been approved and Graupner
cannot evaluate every individual product made by
other companies to assess if they are safe to use.
Liability exclusion / damage compensation
This manual serves only as a source of information
and can be changed without prior notification.
Graupner accepts no responsibility or liability for
errors or inaccuracies which may be contained in this
manual.
Graupner cannot monitor compliance with the
assembly instructions, the operating instructions or
the conditions and methods under which remote
control components are installed, operated, utilized
or maintained. Therefore Graupner accepts no form
Safety notices and handling regulations for Lithium-Ion
(LiIo) and Lithium-Polymer (LiPo) batteries
of liability for loss, damage or costs consequential
to incorrect usage or operation or which can be
attributed to same.
Unless otherwise prescribed by law, the obligation
of Graupner to provide damage compensation,
regardless of legal grounds, is limited to the invoice
value of the quantity of Graupner goods contributing
directly to the damage-inducing event. This does not
apply if Graupner is found to be subject to unlimited
liability pursuant to binding legal stipulations with
respect to intent or gross negligence.As applicable
for all highly technical products, observance of the
following safety notices and handling instructions is
essential for a long service life, fault-free operation,
and harmless utilization of lithium/polymer batteries.
These instructions are to be safeguarded. If the unit is
transferred to another user, these instructions should
certainly be passed along to the new user.
General notices
LiIo-/LiPo batteries require particularly attentive•
handling. This applies to charging, discharging as
well as for storage and other handling. Adherence
to the following special specifications is necessary:
Incorrect handling can lead to explosions, fire,•
smoke and poisoning hazards. Furthermore,
disregard for instructions and warnings can lead to
performance losses and other defects.
The battery's capacity is reduced by every charge/•
discharge cycle. Storing the battery at temperatures
which are too high or too low can also lead to a
gradual reduction in capacity. In model operation,
battery capacity drops to about 50 … 80% of new
battery capacity after about 50 charge/discharge
cycles – even though all charge/discharge rules are
followed. This is due in part to the high discharge
currents and inductive currents caused by motors.
Battery packs may only be connected in series or•
parallel in exceptional cases as cell capacities and
charged state can differ too greatly. This is why the
battery packs we deliver are selected.
Special notices for charging LiIo-/LiPo batteries
from Graupner
Since• Graupner GmbH & Co. KG cannot supervise
the correct charging and discharging of cells,
the entire guarantee is void in cases of improper
charging or discharging.
Never leave batteries being charged unattended.•
Only approved chargers with appropriate charging•
cables may be used for charging LiIo-/LiPo
batteries. Any manipulation to the charger or
charger cables can lead to severe damage.
The maximum charging capacity must be limited•
to 1.05 times the battery's capacity.
Example: 700 mAh battery = 735 mAh max.
charging capacity
Use only the outlet-charger included with the set•
or a specially designed charger/discharger from
Graupner to charge and discharge LiIo-/LiPo
batteries, refer to page 17 or www.graupner.de.
Ensure the settings for the number of cells or for•
final charging voltage and final discharge voltage
are correct. Be sure to observe the operating
instructions for your charger/discharger.
Other handling notices
The battery to be charged must be placed on a•
non-combustible, heat resistant, non-conducting
surface during the charging process. Combustible
or readily ignited objects are to be kept away from
the charging configuration. Batteries may only be
charged under supervision.
LiIo-/LiPo batteries connected in series within•
a pack may only be charged as a group if the
voltage of individual cells do not differ by more
than 0.05 V. The LiIo battery included with the
set, order no. 33000.1 (changes reserved), is
equipped with a special safety circuit such that

8Safety notices
Discharging below 2.5 V per cell damages cells•
permanently and is therefore to be avoided
absolutely. The mc-20 HoTT transmitter switches
itself off when its power supply voltage reaches its
lower limit of 3.3 V. Short circuit conditions are to be
avoided absolutely. Permanent short circuits lead
to destruction of the battery, high temperatures and
perhaps even self-ignition may follow.
During discharge, battery temperature must not•
rise, in any case, to over +70 °C. Otherwise,
better cooling or a lower rate of discharge must
be introduced. The temperature can easily be
checked with the infrared thermometer, order no.
1963. The battery must never be discharged via
the transmitter's charging socket. This socket is
not suitable for this purpose.
Other handling notices
Never short-circuit the battery. A short-circuit•
allows very high current to flow and this heats up
the cells. This will lead to loss of electrolyte, the
production of gases and perhaps even explosions.
In the vicinity of, or while handling, Graupner
LiIo-/LiPo batteries, avoid electrically conducting
surfaces because of the danger of creating a
short-circuit condition.
Handling connectors:•
These connectors are not as robust as for other
batteries. This applies particularly to the plus pole
connector. The connections can easily be broken
off. Due to thermal transfer, the connector tabs
may not be soldered directly.
Cell connection:•
Direct soldering on battery cells is not permitted.
The heat of direct soldering can damage battery
components, such as separator or isolator.
Battery connections should only be made by
industrial spot welding. A professional repair made
by the manufacturer or distributor is necessary to
replace missing or torn-off cables.
Replacing individual battery cells:•
The replacement of battery cells may only be
made by the manufacturer or distributor and never
by the user himself.
Damaged cell usage:•
Damaged cells may never be used or returned to
service.
Characteristics of damaged cells include:•
damaged housing packing, deformed battery cells,
electrolyte or leaking electrolyte. In these cases,
further use of the battery is not permissible.
Damaged or useless cells are hazardous waste•
items and must be appropriately disposed.
General warning notices
Batteries must never be put in fire or burned.•
Battery cells must not be submerged in liquids,•
such as water, seawater or beverages. Any contact
with liquids, of whatever nature, is to be avoided.
Individual battery cells and batteries are not toys•
and must therefore not get into the hands of
children. Batteries/cells must be kept out of the
reach of children.
Batteries must not get into the vicinity of babies or•
small children. If a battery is swallowed, immediately
go to a doctor or emergency medical facility.
Batteries must not be put in a microwave oven or•
put under pressure. Smoke, fire and more can be
the consequences.
Never dismantle a LiIo-/LiPo battery. Dismantling•
a battery can cause internal short-circuits. Gas,
fire, explosions and other problems can result.
The electrolyte and electrolytic vapors in LiIo-/LiPo•
batteries are harmful. Absolutely avoid all direct
contact with electrolytes. If electrolytes come
into contact with skin, eyes or other body parts,
immediately wash out or rinse out with generous
amounts of fresh water then be sure to consult
"compensation" for voltage differences between
individual cells, by way of an otherwise typical
balancer plug connection, is not necessary.
Under these conditions• Graupner LiIo-/LiPo
batteries can be charged with a maximum of 2C
(the value 1C corresponds to the cell capacity)
charging current. At a voltage of maximum 4.2 V
per cell and above, charging must continue a
constant voltage of 4.2 V per cell until charging
current drops below 0.1 … 0.2 A.
Charging voltage over 4.20 V per cell must be•
avoided absolutely as the cell would otherwise be
permanently damage and could cause a fire. In
order to prevent the over-charging of individual cells
in a pack, a cut-off voltage between 4.1 V … 4.15 V
per cell should be set to increase service life.
Never attempt to charge battery cells with the•
wrong polarity. Abnormal chemical reactions take
place when batteries are charged with reversed
polarity and the battery will be useless. This can
cause breaks, smoke and flames.
The permissible temperature range for charging•
and storing LiIo-/LiPo batteries is 0 … +50 °C.
Storage: LiIo-/LiPo cells should have a 10 … 20%•
charge capacity when stored. If cell voltage drops
below 3 V, then LiIo-/LiPo cells must absolutely
be recharged to a capacity of 10 … 20% of full
capacity. Otherwise, further deep-discharging of
the battery will make it useless during storage in a
discharged state.
Special notices for discharging LiIo-/LiPo
batteries from Graupner
A continuous current rate of about 1C does not•
represent a major problem for Graupner LiIo-/LiPo
batteries. For larger currents, please follow the
catalog specifications. In any case, observe the
maximum current rating for the connector system,
see maximum discharge current on the battery.

9
Safety notices
a doctor.
Batteries built into equipment must always be•
removed from that equipment when it is not
currently in use. Alway switch off equipment after it
is used to prevent deep discharging. Always charge
batteries before it is too late. Store batteries on a
non-combustible, heat resistant, non-conducting
surface! Deep-discharged LiIo-/LiPo batteries are
defective and may no longer be used!
Notice for remote control set mc-20 HoTT
Order no. 32032
This remote control set is factory equipped with a
Lilo transmitter battery (changes reserved). Once
the factory preset voltage limit of 3.60 V has been
reached, a warning will appear in the display.
Disposal of used batteries:
Some countries have laws requiring that all used
batteries be turned over to an authorized collection
center.
Disposing of batteries along with common household
garbage is forbidden. Old batteries can be turned into
communal collection centers for disposal at no charge
or they can be returned to one of our dealerships or
anywhere else where batteries of that given type are
sold. Used batteries we have delivered can also be
sent back to us, at your cost, through the mail. Use
the return address below:
Graupner GmbH & Co. KG
Service: Used batteries
Henriettenstr. 94-96
D-73230 Kirchheim unter Teck
This represents an essential contribution to
environmental protection.
Caution:
Damaged batteries require among other things,
special packaging, because they are very toxic!

10 Foreword
mc-20 the Newest Generation of Remote Control Technology
The technical advances across the entire spectrum
of model building is an ever-present challenge to
design engineers. This is why the introduction of
new transmission technology in the 2.4 GHz band
represents a new milestone.
The HoTT-System (Hopping Telemetry Transmission)
developed by Graupner is a synthesis of know-how,
engineering and testing done around the world by
professional pilots.
Established Graupner HoTT techniques theoretically
permit over 200 models to be operated at the same
time. However, because of the interspersed radio-
frequency utilization permitted by certification for the
2.4 GHz ISM band, this number is significantly lower
in practical application. Nevertheless, in general
more models can be operated simultaneously in the
2.4 GHz band than would be the case in conventional
35 or 40 MHz frequency bands. The real limiting
factor is–as often before– is still likely to be the
size of available operating space (i.e. airspace for
aircraft). Alone the fact that it is no longer necessary
to coordinate transmitting frequencies with other
pilots in the vicinity (which is sometimes quite difficult
in broken landscapes, such as on hillside slopes)
represents an enormous boost for remote control
operating security.
Bidirectional communication between transmitter
and receiver, by way of a return channel built into
the receiver, permits convenient access to data and
programming in the HoTT receiver. For example,
this makes it possible to swap receiver outputs or to
divide up control functions among multiple servos
(channel mapping). Servo travel and servo rotation
directions in the receiver can also be matched to
one another with these facilities. Telemetry data,
like VARIO and GPS data, can be called up from
optionally available modules.
Based on the mc-24 Graupner/JR computerized
remote control system, the mc-20 HoTT remote
control system has been especially developed for
experienced RC pilots All conventional model types
can be readily operated with the mc-20 HoTT
system, regardless of whether the model is a winged
aircraft, helicopter, ship or land vehicle.
Complex mixed-control functions of guiding surfaces
are often necessary for winged aircraft (rudder,
elevators) and helicopter models (swashplate).
Thanks to modern computer technology, very diverse
model requirements can be programmed in the
simplest conceivable manner with touch-sensitive
keys (CAP Touch). Simply select the given model
type from the mc-20 HoTT program and its software
will assemble all significant mixer functions and
coupling functions automatically. This eliminates
the need for separate modules in the transmitter
to implement complex coupled functions and also
makes sophisticated mechanical mixer mechanisms
in the model unnecessary. For example, this makes
the mc-20 HoTT transmitter fully equipped with both
software and hardware to operate the well-known
NAUTIC modules on the receiver side. The "channel
sequencer" is new. It permits the operation of up to
three servos to be automated.
The mc-20 HoTT system offers optimal security and
reliability without having to forgo great operating
convenience. The mc-20 HoTT remote control
system has 80 model memory locations. Additional
flight-phase-specific settings can be stored in every
model memory location. For example, such settings
can be made for various parameters that can be
called up to implement particular flight maneuvers at
the "press of a button". Additional model memories
can be stored on the SD card, which is included
standard with the set. Even telemetry data can be
recorded for subsequent evaluation on a PC.
Since the mc-20 HoTT is equipped with two
displays, the lower display has been optimized for
comprehensible, simple operation of the software.
The graphic representation of mixer functions
is particularly helpful. The upper display allows
telemetry data to be called up from the receiver.
Functionally-related options are clearly arranged
by content in a simple organization. The clear,
comprehensible program structure permits a beginner
to quickly become familiar with the various functions
and able to use all options pertinent to his level of
expertise with remote control models.
This handbook describes every menu in detail. There
are tips, many notices and programming examples to
supplement the descriptions and also explanations
for model specific technical terms, like transmitter
control, dual rate, butterfly, and so on.
Please observe the safety notices and technical
notices. Read through the instructions attentively.
Before usage, test all functions by simply attaching
servos to the receiver included in the set. While doing
this, observe respective notes on page 68. This will
help you learn the essential operating techniques and
functions of the mc-20 HoTT.
Always handle your remote controlled model with a
sense of responsibility so that you do not endanger
yourself or others.
The Graupner team wishes you much pleasure
and success with your mc-20 HoTT, the newest
generation of remote control systems.
Kirchheim-Teck, December 2011

11
Remote control set description
metsySretupmoC mc-20
-zHG4.2niteslortnocetomerlennahc23 Graupner-HoTT technology
(Hopping Telemetry Transmission)
Technology that enthralls
The superior functional security of Graupner
HoTTTechnology accomplished with bidirectional
communications between transmitter and
receiver with integrated telemetry, freely
programmable voice output via headset
connector, and ultra-fast response times.
PrQITCOOKPIKUUKORNKſed by a programming
technique implemented with capacitive touch
buttons.
High contrast, 8 line, graphic display for perfect
presentation of all parameter settings. Switch
on/off of blue back-lighting at will. A second,
independent display for presentation of telemetry
data. Storage of telemetry data on a micro
SD memory card.
4096 steps of 12-bit resolution on the channel
signal assures extreme control sensitivity.
USB connection to read and write the model's
memories as well as fQTOCMKPIſrmware updates
Integrated• Graupner HoTT 2.4 GHz transmission
system
Maximum interference immunity made possible b•
optimized frequency hopping through as many as
75 channels and wider channel spread
Intelligent data transfer with correction function•
Over 200 systems can be used simultaneously•
The HoTT technique of bidirectional•
communication between sender and receiver,
as well as the fastest possible transmission rate
(10 ms) assures extremely short reaction times.
5 different languages (German, English, French,•
Italian and Spanish) available per software
update. For the availability of a given language,
refer to the download area.
80 model memories with storage for all model-•
speciſc programs and parameter settings
Seven switches (two 3-way switches, three 2-way•
switches and two 2 pushbutton switches) as well
as three digital actuators are already built-in and
can be used as desired
A function encoder with two touch-sensitive,•
four-way keys ("CAP Touch") permit simpliſed
programming and precise settings
Key-lock function to prevent unintentional•
operation.
Voice and, as applicable also MP3 ſle, output over•
headset output or loudspeaker
Simple, very fast model-independent binding•
Extremely fast rebinding, even at maximum•
distance
Range: test and warning function•
Under-voltage warning•
Extremely wide receiver operating voltage range•
of 3.6 V to 8.4 V (functional to 2.5 V)
Fail-safe, free channel assignment (channel•
mapping), mixer functions and all servo settings
are simple to program

12 Remote control set description
Binding of any number of receivers to the channel•
expansion (32 channels maximum)
As many as four servos can be controlled•
simultaneously as a block in the SAME operating
mode with a servo cycle time of 10 ms (digital
servos only).
Thanks to cycle time reduced down to as little•
as 10 ms, extremely short response times are
achieved.
Real-time telemetry evaluation in the transmitter•
display Additionally, telemetry data can also be
selectively displayed by the SMART-BOX.
Additional HoTT features of the mc-20
Super-fast response time through use of a fast•
main processor for data transmission.
Micro-SD card for storage of telemetry data and•
for additional functions
Obsolescence-proof through update capability over•
USB interface as well as via the micro-SD card
The included Lilo battery (changes reserved)•
has a capacity of over 6000 mAh. This makes
extremely long flight times possible and also
reduces the number of charging repetitions.
Modulation changeover per software: e.g. from•
"EXT. PPM" (e.g. Weatronic) to HoTT at the press
of a button.
Swashplate limiting: This function limits the•
swashplate's tilt angle to prevent the potential for
mechanical collision in helicopter 3D operation at
full-limit roll and pitch-axis
Ring-limiter:• functions similar to swashplate
limitation but is used for control of up to three
Voith-Schneider drives in ship models
Channel sequencer for automating servo motion•
sequences of up to three servos, e.g. to automate
the lowering of landing gear or to extend/retract
drives in self-launching gliders
Multi-channel function for operating• Graupner
product line NAUTIC modules
Digital trimming with pseudo »analog« endless•
pinions, effective per specific flight-phase
Auto-trim function. The current joystick positions•
for trimming fixed-wing or helicopter models will
be stored in trim memory at the press of a button.
(Model »compensation«, activate switch and
release joystick. The correction will be blended in
»gently« upon return of the joystick.
C1 changeover, brake/elec. motor: This•
changeover can be implemented very easily via
enhanced flight phase programming.The pilot
determines the joystick positions (forward/rear) at
which the motor is to switched off or the airbrakes
are to be retracted.
16 control functions maximum•
Simplified arrangement of operating elements,•
such as joysticks, external switches, proportional
controls and trim levers as control functions
Protection against obsolescence is provided•
by virtue of a fast 32-bit operating system with
modern flash memory that can be updated.
Blue back-lighted MULTI-DATA-GRAPHIK-LCD•
monitor with significantly better legibility under
unfavorable light conditions
CONVENIENCE MODE SELECTOR to simplify•
changeovers between operating modes 1 … 4
(e.g. throttle left/throttle right)
Two freely programmable mixers for fixed-wing•
or helicopter models, each with freely selectable
input and output functions; four curve mixers
with innovative 8-point curve technology for
easy to set and adjust curve values at up to
eight points for throttle, pitch, tail or other non-
linear characteristics. The arithmetic unit in the
CPU employs an ingenious method of calculating
polynomial approximations for truly-rounded, ideal
MPC (multi-point curve) mixer curves
Bi di f b f i t th h l d t li NAUTIC d l
Computer System mc-20
32 channel remote control set in 2.4 GHz Graupner-HoTT technology
(Hopping Telemetry Transmission)
Shifting curve mixer points can be done along•
both axes with the CAP touch pad keys
Eight flight-phase programs can be individually•
adapted for each model and given a name. The
switchover time is programmable separately.
SUPER SERVO menu with a perfect overview•
of all servo setting data and simple parameter
correction at four "levels": direction of rotation,
mid-point setting, separate servo travel on both
sides and separate travel limiting on both sides for
16 servos with a total of 96 setting options
SUPER-DUAL-RATE, EXPO and EXPO/DUAL-•
RATE menu with 36 potential setting variants for
three servo functions and six flight phases
Practice-optimized multi-function menu for•
aerofoils and helicopter models. Entry of the
number of aileron and flap servos automatically
programs all necessary mixer functions in the
multi-function "Wing mixers" menu. Differential
aileron mixer, butterfly mixer, dual-flap mixer,
automatic gyro set function and other special
functions
Helicopter swashplate mixer for 1, 2, 3, or 4 point•
steering.
Selectable cycle time: 10 ms or 20 ms/30 ms,•
depending on receiver and operating mode
A convenient timers menu with a system of eight•
stopwatches, alarm timer, countdown timer, laps
counter and so on. Two running timers and one
lap timer can be displayed at the same time in
large characters.
Stopwatch with history: In addition to the lap•
counter there is a "Time 1" which captures the
switch-on time and a "Time 2" which records the
ON and OFF times separately
Channel mapping• in the receiver allows free
distribution of control functions.
The travel distance and rotation direction settings•

13
Remote control set description
integrated into the receiver make it possible, for
example, to match up mapped servos with one
another
The programmable fail-safe functions »Hold«,•
»Off« and »Move to preset positions« that are built
into the receiver for every individual servo channel
can be set separately
A slot for FAT or FAT32 formatted SD and SDHC•
memory cards is available on the transmitter for
log files and model programs
Model programs
Transmitter operating time timer•
Flight phase switch assignments: six switches, two•
with a priority function. Every switch combination
can be named freely. This makes the number of
flight phases independent of the number of flight
phase switches.
Tail type normal, V-tail, Delta/flying-wing and 2 HR•
Sv 3+8 (which immediately makes two coupled
elevator servos available without using free mixers
or dual mixers)
Flap count 4 AIL/4 FL: Full support of eight wing•
servos, even without use of free mixers
Flight phase switching cutoff delay:•
the delay time can be switched off for individual
channels on a flight-phase basis (e.g. for motor
off in electric models or to activate/deactivate
helicopter head lock).
Ten additional, user definable phase names: aside
from the prescribed flight phase names, the user
can also freely assign up to ten phase names of
his own choice.
Enhanced transmitter control menu: option to•
assign input-side mid-point setting for C1 control +
trim as a transmitter control. A single input can be
assigned to two switches for a true 3-way switch
function.
Wing mixers: New concept for the multi-flap menu•
to simplify settings of one to eight wing servos on
a flight-phase specific basis in a comprehensible
manner without requiring the use of free mixers
»Info« sub-option in the Base setup model menu•
Any kind of additional information about every
model can be entered here. This additional
information will then appear in the newly designed
model select function
»Logical switches«: this function permits two•
switches to be coupled as »and« or »or« logic
functions. The result can be employed as a
virtual switch. Typical application: The activation
of certain functions should only be possible in
conjunction with other functions, e.g. wheel brake
can only be activated when the landing gear is
down. A number of functions which are normally
independent of one another, are to be put in their
base settings by way of an »Emergency switch«.
This program automation can be activated by
multiple switches that also select the appropriate
program.
Servo-middle setting range extended to ±125%•
Number of flight phases: (fixed-wing: 8, helicopter:•
7 + AR)
Settable »Throttle too high« warning threshold•
in the helicopter menu, programmable switch-on
warning
Time-frame can only be stopped, and thus also•
erased, (if the timer switch is in its OFF position)
by touching the center ESC key while the ef or
cd selection keys are also being touched.
Phase trim for all axes of fixed-wing models•
possible
Hotkey for servo display: one tap on the• eand
fkeys of the left CAP touch pad (touch sensitive
keys) will call up the servo display directly from
virtually all menus.
Servo occupancy swap on the receiver output•
CAP TOUCH operating elements with key lock•
function to prevent unintentional operation.
CAP TOUCH display change from the main menu•
to the telemetry main menu via ESC.
Numerous telemetry displays, programming•
functions and evaluation functions are presented
directly in the transmitter's screen
Graphic presentation of model icons for the model•
type display (fixed-wing/helicopter)
Built-in connector sockets for PC-USB interface,•
headset, SMART BOX, external RF module,
DSC system. Prepared for teacher/pupil operation.
Teacher/pupil system with or without cable for•
complete transfer; all settings are made on the
teacher transmitter.
Additional functions are planned for•
implementation via software update.

14 Remote control set description
ehtrofatadlacinhceT -HoTT transmitter
Frequency band 2.4 … 2.4835 GHz
Modulation FHSS
Region EURO or FRANCE,
see page 261
Control functions 16 functions, 4 of these can be
trimmed
Temperature range -10 … +55 °C
Antenna collapsible
Operating voltage 3.2 … 4.8 V
Current draw about 500 mA
Range up to about 4 000 m
Dimensions about 252 x 252 x 60 mm
Weight about 1,685 g with transmitter
battery
Receiver GR-32 Dual HoTT
Graupner HoTT 2.4 GHz technology gives the dual-
receiver a new Hopping Telemetry Transmission high-
frequency section with state-of-the-art components
and software. The dual-receiver has two complete
receiver sections and additional hardware antenna
diversity. Reception is always switched over to
the better antenna signal and, for transmitting,
the antenna last used for receiving will always be
used. Thus it is assured that return channel data
is transmitted via the better positioned antenna.
Parameters for receiver supply voltage, receiver
temperature and signal strength are transmitted
without any additional sensors.
The receiver has a connector for telemetry sensors
and one for sum signal input or output.
The receiver has six battery inputs to make it an
excellent power source for even high-load servos.
Accessories
Order No. Description
71.26 Transmitter straps, Graupner HoTT
72.40 Transmitter straps, deluxe
Teacher/pupil cable for mc-20 HoTT
see page 213
Replacement parts
Order No. Description
3080 Aluminum transmitter case, HoTT,
400x300x150 mm
33000.1 Transmitter battery, ƀat LiIo, single cell six-
pack/6000 3.7 V TX
33002.1 Micro-SD card, 2 GB for HoTT transmitter
33032.2 Transmitter metal hanger for mc-20
33032.3 Hand rests for mc-20 (2 piece)
33801 HoTT transmitter antenna
Technical data for the GR-32 Dual HoTT receiver
Order no. 33516
Operating voltage 3.6 … 8.4 V*
Current draw about 140 mA
Frequency band 2.4 … 2.4835 GHz
Modulation FHSS
Antenna 2 x 2 diversity antennas,
about 145 mm long, about
115 mm of this length
encapsulated and about
30 mm active
Plug-in servos 16
Plug-in sensors up to four sensors
Temperature range about -10 … +55 °C
Range up to about 5 000 m
Dimensions about 63 x 30 x 14 mm
Antenna length 4 x wire 145 mm (active
antennae 30 mm)
Weight about 24 g
* The speciſcation for permissible operating voltage range applies
only to the receiver. Please note in this context that receiver
input voltage is applied without regulation to connected servos
but the voltage range for most connectible servos (speed
controls, gyros, etc.) is only 4.8 to 6 V.
The set, order no. 33032, includes
Microcomputer transmitter• mc-20 HoTT with
built-in LiIo single cell six-pack/6000 mAh/3.7 V
transmitter battery (change reserved)
Electric outlet charger (4.2 V, 500 mA)•
Graupner• bidirectional receiver, GR-32 Dual
HoTT (order no. 33516) for connection of up to 16
servos
USB adapter/interface (order no.•7186.6) including
suitable USB cable for connection to a PC and an
adapter cable for receiver updates
Micro-SD card (2 GB) with an adapter for a card•
reader
Sturdy aluminum transmitter case with foam•
cushioning (order no. 3080)
Other accessories in Internet at www.graupner.de.
Contact or visit your local dealer. He will be glad to
provide advice.
Thildtf th
mc 20 H TT t itt ThilTh t d 33032 i l d
Computer System mc-20
32 channel remote control set in 2.4 GHz Graupner-HoTT technology
(Hopping Telemetry Transmission)
33020, includes

15
For your notes

16 General operating notices
General operating notices
Transmitter
Transmitter power supply
The mc-20 HoTT transmitter is equipped with
a high-capacity, rechargeable LiIo 1s6p/6000
3.7V TX battery (order no. 33000.1) as standard
equipment. (changes reserved) However, the
standard built-in battery is not charged upon
delivery of the transmitter.
When the transmitter is used, its battery voltage
should be monitored by way of the indicators provided
in the LCD display. If the voltage level preset in the
"Battery warning" line of the »General basic settings«
menu, page 260, (default setting 3.60 V) is underrun,
an acoustic signal will be sounded and a warning
message will appear in the display.
#01 0:00h
Stoppuhr
Flugzeit
K78
0:00.0
3.5V
0:00.0
00
0
0
0:00h
M
V
Batt must
be re-
charged!!
No later than now, operation must be terminated so
the battery can be charged again.
Note:
Be sure the correct battery type is set in the »General
basic settings« menu, page 260!
The standard setting for this is "Lith.".
Charge the transmitter battery with the plug-in
charger.
The transmitter's rechargeable LiIo battery can be
charged by way of the charger socket located behind
a cover on the left, front side of the transmitter –as
viewed from the front– with the included plug-in
charger (order no. 32032.4).
Depending on the state of discharge, the included
plug-in charger (4.2V/500 mA) requires up to about
15 hours to fully recharge the transmitter battery.
Never use plug-in chargers from other manufacturers
or chargers intended for other battery types. Charger
output voltage which is too high or possibly even
different plug polarity, see further below, can cause
immense damage. We recommend that this plug-in
charger be appropriately labeled.
Also observe the safety notices provided on pages
4 … 7.
The transmitter must be switched "OFF" during
the entire charging procedure. Never switch on the
transmitter when it is connected to the charger. Even
a brief interruption to charging can cause charging
voltage to rise to a level that will immediately damage
the transmitter with over-voltage. Also for this reason,
be sure all connectors are always plugged in securely
and have good contact.
Opening the transmitter housing
Switch off the transmitter before opening it (power
switch to »OFF«). Push both housing base latches in
the opposite the direction of the arrow marks, toward
the inside, to their limits. Now tilt the transmitter
somewhat to the rear so the housing base can flip
open and can be unhooked. Close the transmitter's
housing base by first hooking it to the underside, flip
the base closed then push both latches toward the
outside. When closing the base, pay attention that no
cables are pinched.
Notes:
Make no modifications of any kind to the•
circuit boards as this will void the guarantee
as well as the unit's official permit.
Be sure not to touch the circuit boards with•
any metallic objects. Do not touch contacts
with your fingers.
Before performing any tasks inside the•
transmitter, disconnect the transmitter's battery
(see next page) to avoid potential short circuit
damage to the transmitter's circuit boards.

17
General operating notices
Charging with automatic chargers
To achieve quicker recharging of the single cell LiIo
battery, Graupner automatic chargers can also be
used. The table below shows a selection of these
chargers.
Recommended chargers (accessory)
Order
No. Designation
Input voltage 220 V Input voltage 12 V
suitable for
battery types
integr. balancer NiCd NiMH LiPo/LiIo lead battery
6411 Ultramat 8 xxxxx
6463 Ultramat 12 plus x x xxxx
6464 Ultramat 14 plus x x x xxxx
6466 Ultra Trio plus 14 x x x xxxx
6468 Ultramat 16S x x x xxxx
6469 Ultra Trio Plus 16 xxxxx x
6470 Ultramat 18 x x x xxxx
6475 Ultra Duo Plus 45 x x x xxxx
6478 Ultra Duo Plus 60 x x x xxxx
6480 Ultra Duo Plus 80 x x x xxxx
Charger cable, order no. 3022 is additionally needed for the
transmitter and charger cable, order no. 3021 is additionally
needed for the receiver.
Other charger units and details about the listed chargers can
be found in the Graupner RC main catalog or in Internet at
www.graupner.de.
The charger socket is equipped standard with a
diode to protect against reversed polarity. Original
Graupner automatic chargers also detect battery
voltage polarity.
Observe the configuration notices for the charger
used.
First connect the charger cable's banana
plugs to the charger and only then connect
the cable's other end into the charging jack
on the transmitter. Never allow the bare ends
of the banana plugs to come into contact with
one another when the other end of the cable is
plugged into the transmitter.
Charging current may not exceed 1.5 A as
otherwise the diode, and perhaps other
components, could be damaged. If necessary,
limit the current at the charger.
mc-20 HoTT charging jack polarity
The charger cables on the market from other
manufacturers often have different polarities.
Therefore use only an original Graupner charger
cable, order no. 3022.
Removing the transmitter's battery
To remove the transmitter's battery, first unlatch the
cover of the battery compartment on the rear side of
the transmitter housing then remove the cover.
Take out the transmitter's battery then disconnect the
transmitter battery's connector by carefully pulling on
the supply line cable.
Inserting the transmitter's battery
The battery connector is protected against a
reverse polarity connection by two slanted edges,
see illustration. When correctly plugged in, the
unconnected pin of the connector is at the bottom,
as shown in the illustration. The plus
pole (red lead) is in the middle and
the minus pole (brown or black lead)
is toward the antenna side.
Never try to force the connector
onto its circuit-board socket.
Place the battery into its
compartment and close the transmitter's cover.
Transmitter
connector polarity
Battery connector
Battery connector

18 General operating notices
Battery operation timer at the bottom left of the
screen
This timer shows the transmitter's cumulative operating
time since the transmitter's battery was last charged.
This timer is automatically reset to "0:00" when the
transmitter is switched on and its battery voltage is
significantly higher than when the transmitter was last
used, e.g. because the battery was charged.
#01 0:00h
Stop watch
Flight tim
K78
0:00.0
4.1V
0:00.0
00
0
0
0:00h
M
V
Lithium battery, CR 2032
On the side of the transmitter board opposite the
transmitter battery there is a fixture containing a
lithium battery, type CR 2032, which can be replaced
by the user.
This battery maintains the date and time settings
during a transmitter power supply outage, for
example when the transmitter's main battery is being
replaced.
Joystick length adjustment
The length of both joysticks can be continuously
adjusted to adapt these transmitter controls to the
pilot's preference.
Hold the lower half of the knurled grip in place then
turn the upper section to release its counter-locked
threads.
Now pull up or push down on the joystick's end to the
desired length. When the length is suitable, tighten
the counter-locked threads of the upper and lower
sections again.
Lithium battery
Lithium battery

19
General operating notices
Joystick restoring force
The joystick's restoring force can also be adjusted
to the pilot's preference. The adjustment is located
next to the return springs, see markings in the figure
below.
Spring force for the given direction of motion can
be adjusted by turning the respective screw with a
Phillips screwdriver.
clockwise = stronger return,•
counter-clockwise = weaker return.•
Note:
The aggregate for the right joystick is a mirror image
of the left joystick so corresponding screws for the
right joystick are located to the right of the middle.
Joystick conversions
Neutralization
Both the left and the right joystick can be configured
for neutralized or non-neutralized operation. Open the
transmitter.
To change the joystick's factory setting, locate the
screw shown in the figure below enclosed in a white
circle.
Note:
The aggregate for the right joystick is a mirror image
of the left joystick so the corresponding screw for the
right joystick is on the right side just below the middle.
Now turn this screw down until the respective joystick
is free to move from limit to limit - or turn the screw
out until the joystick again completely self-restoring.
Brake spring and ratchet
The outboard screw of the two marked in the next
figure adjusts the braking force and the inboard screw
adjusts the strength of the ratchet for the respective
joystick.
Note:
The aggregate for the right joystick is a mirror image
of the left joystick so corresponding screws for the
right joystick are located at the top left.
vertical
vertical
horizontal
horizontal

20 General operating notices
Holder bracket for transmitter straps
A stable transmitter hanger for fastening neck
straps is standard equipment on the mc-20 HoTT
transmitter.
To unfold the holder brackets, first press both
brackets inward a bit near where they are lettered
then turn them upward by 90°. The brackets will
automatically lock into position.
If you have a neck strap fastened to the holder
bracket with key-rings, first press lightly on the right
holder bracket to release its latch so it can be folded
down then do the same with the left holder bracket.
Afterward, press both brackets SIMULTANEOUSLY
into the recess.
The following straps are available as accessories:
Order no.Description
71.26 Transmitter straps, Graupner HoTT
72.40 Transmitter straps, deluxe
Installation of switches, switch modules and knob
modules
There are a total of 20 holes in the transmitter's
housing available for mounting accessory modules.
To be safe, always disconnect the transmitter battery
before installation to avoid short circuit conditions.
Be sure to pay attention that soldered points on the
transmitter board do not come into contact with metal
objects!
Unoccupied holes in the transmitter's housing are
closed with blind plugs. These can easily be pulled
out from the outside with one's fingernails.
Insert the accessory switch, etc. through a hole in the
housing from the inside.
Accessory switches, potentiometers, etc. are
fastened into place by screwing a nut onto the
threaded shaft protruding though the housing and
tightening it with a suitable wrench. If the control has
a knob, it can be reattached after the nut is tightened
down. Trim nut wrench (order no. 5733) is well suited
for tightening down these nuts.
Trim nut wrench (order no. 5733) is well suited
for tightening down switch element trim nuts.
Aligning the antenna
The removable, articulated antenna is to be screwed
into the ball-joint connector then aligned by hand.
The antenna exhibits very limited field strength
straight out from its end, pointing it directly toward the
model is wrong.
When screwing in the antenna, pay attention that the
center pin in the antenna socket does not get bent or
pressed back in the socket.