Apr 152012

What a wonderful day to test fly a new airplane or radio system!  When I arrived at the field, Jim had already set up the highstart.  We were joined by Newt  shortly thereafter.

I had installed the receiver (12 channel) that came with the radio in my trusty Vision thermal duration glider.  Sandy at Graupner USA was a pleasure to deal with.  The radio system is delivered with the 12 channel transmitter and a 12 channel receiver already bound at the factory.  All I had to do was to adjust the ratchet and stick neutralization for the left stick (I fly mode 2).  The manual is the best I have read so far for any radio system (JR, Futaba, Spektrum, Multiplex).  It is delivered in print and also as a file on the included 2GB SD card.  I was able to set up a program for my Flying Special 5000, a scale glider and the Vision in about 75 minutes.  Not bad at all.  None of them required any programming of mixers, as the radio software has pretty much all configurations covered, including the 8 servo wing on the FS5000.  The radio has outstanding telemetry capabilities.  It displays the receiver battery voltage and you can set a ‘low alarm’.  That alone was worth it to me.  In addition, you can add various sensors, e.g. a vario, a vario/GPS, etc.  They are very competitively priced, as is the radio.  The sensor / vario data is stored on the SD card and can be visualized on a personal computer.  While I am currently using the provided 4-cell 2000mAh transmitter battery, it will run from the available 1s6p 6000 (six thousand) mAh LiPo.

I now have about two hours of flight time on it a really like it.  It got many favorable comments regarding functionality, ergonomics and looks.  The display was easy to read in the bright sunlight without and with (polarized) sunglasses.


Here’s the description from the Graupner USA website:


With 12 control functions, the mx-20 HoTT lets the advanced RC model builder to control nearly any model. The use of Graupner HoTT 2.4-GHz transmission technology ensures great functional reliability through bidirectional communication between transmitter and receiver, with integrated telemetry, voice output via headphone output, and ultrafast response times.
The transmitter has 24 model memories. Simplified programming using touch keys. A contrast-rich, 8-line, blue-lit graphic display ensures perfect display of all setting parameters and telemetry data. Telemetry data and additional model memories can be stored on a micro-SD memory card. (later after update)
The channel signal is resolved at 12 bits in 4096 steps, thus providing extremely sensitive control.
USB connection for reading out and storing model memories and for firmware upgrades.

  • Microcomputer remote control system with state-of-the-art 2.4 GHz Graupner HoTT technology
  • Bidirectional communication between transmitter and receiver
  • 5 different languages (German, English, French, later Italian, and Spanish) possible via software update. For availability of the respective language, see Download area.
  • Servo cycle times of 10ms can be selected for digital servos
  • Ultrafast response times through direct transmission of the data from the main processor to the 2.4-GHz transceiver with reliable transmission. No additional delays through detours via a module processor
  • Short aerial, foldable
  • Operation and programming based on the proven concepts of mc-19 to mc-24
  • A contrast-rich, blue-lit graphic display ensures perfect control of settings and parameters such as model type, model memory, clocks, and operating voltage
  • 12 control functions
  • Free assignment of all switches
  • 24 model memories
  • 7 switches/keys, including 2 3-stage-switches, 3 2-stage switches, 2 keys, 3 analogue switches already installed
  • Modes 1 to 4 are freely selectable
  • CAP-TOUCH key with key lock function to prevent unintentional operation
  • CAP-TOUCH display change from main menu to telemetry main menu using the ESC key
  • Numerous telemetry display, programming, and analysis functions directly in the transmitter display
  • Voice output can be called up via freely programmable switches
  • 7 flight phases can be programmed
  • Extensive programmes for fixed-wing and helicopter models
  • Swashplate limiter
  • Voith-Schneider limiter, similar to a swashplate limiter (later after update)
  • Door Sequencer e.g. to automatically extend landing gear or operate flap drives with process control (later after update)
  • Servo travel adjustment/B>: can be set separately for all servo channels and for each final value
  • Sub-trim to set the neutral position of all servos
  • 2-stage expo/dual-rate system, individually adjustable, can be switched during flight
  • Mixer functions Programmable failsafe function »Hold« or »Advance to pre-set positions« adjustable separately for each individual servo channel
  • Stop watches / countdown timers with alarm function
  • Model copy function for model memories


The set includes:
Graupner HoTT mc-20 microcomputer telemetry transmitter with built-in NiMH 2000 mAh transmitter battery, Graupner HoTT GR-24 receiver, and 100mA transmitter charger

General HoTT features:

  • Simple, extremely fast binding
  • Range test and warning function
  • Low-voltage warning
  • Extremely broad receiver operating voltage range from 3.6 V to 8.4 V (functional to 2.5V)
  • Failsafe, free channel allocation (channel mapping); mixer functions and all servo settings can be programmed simply with the HoTT-Smartbox
  • Binding of any number of receivers for channel expansion (max. of 32 channels)
  • Up to 4 servos can be controlled simultaneously as a block with a signal repetition time of 10 ms (only digital servos!)
  • Maximum immunity to interference through optimised frequency hopping and broad channel spread
  • Intelligent data transmission with correction function
  • Extremely fast rebinding, even at max. distance
  • Telemetry analysis in real time
  • Over 200 systems can be used simultaneously
  • Future-proof through update capability via USB interface