OTXSIM debugging tool

Last updated 18 June 2021 - Mike Shellim


OTXSIM is a glider simulator script for debugging your setups.

It's designed to be run in the Companion simulator. As you move the sticks in the sim, a live graphic is shown, together with mixer values for the primary channels. A list of GVARs is displayed, and you can simulate different values.

OTXSIM guesses which control surface goes with each channel by looking at the channel label, however you can override it where it gets it wrong.



OTXSIM version 1.2 (5 May 2020)

For Companion 2.2 and higher, with X9D profile



Download/install (once only)

  1. Download the script, and change the file extension from '.txt' to '.lua'
  2. Copy the script file into the \SCRIPTS\TELEMETRY folder of the SD Structure path (specified in Companion settings).
  3. Start Companion and select a profile for X9D/X9D+
  4. Open the .otx file containing the model to be tested
  5. Select the target model
  6. In the Telemetry menu, scroll to bottom, set the first screen to 'script' + otxsim
  7. Save the .otx file

The screen definition for OTXSIM is now saved with the model.


To run the script:

  1. Start Companion and select the model
  2. Start the OpenTX simulator
  3. From the splash screen, press {long PAGE} until OTXSIM is displayed.

The following buttons/computer keys are used for navigation:

Drawing conventions

The surfaces are drawn assuming the following convention:

Individual surfaces can be reversed via the Configuration page.

Auto configuration

At startup, OTXSim looks at the channel names and makes an informed guess as to their function. For example, a channel name containing 'v' and 'r' is mapped to the right V-tail panel. Suggested control surface names for auto-configuration:

If the auto configuration fails, surfaces can be manually assigned in the configuration page.


OTXSIM is designed as a developement tool only. It's recommended to remove it from the final setup before flying.