This is a small request-app, purpose is very simple, user want’s to know the head- or tailwind model experiences in the air.

Requirements for WindSpeed

  • Airspeed sensor, units in “km/h” or “mph”
  • Groundspeed, GPS for example, units in “km/h” or “mph”
  • Units from both sensors needs to be the same
  • Transmitter with firmware 4.27 or newer

Functions for WindSpeed

  • Calculates the difference of air- and groundspeed
  • Telemetry-window available with text “Headwind” or “Tailwind”
  • Adds telemetry-value “Windspeed” to model’s log-file
  • Wind speed unit is displayed as m/s if you have speed unit as km/h, for mph-users wind speed is also mph.
  • Possibility to assign a switch for announcement, example “Headwind 12.3 meters per second”


I did not go “all the way”. In order to calculate windspeeds in dive for example the need for different sensors values would increase dramatically. So the value is simply head- or tailwind in level flight.


In short: Copy the (or .lua, the .lc is memory-optimized) file from github here to your transmitters Apps-folder, copy the RCT-Wind.jsn file from Lang-folder to Apps/Lang-folder on your transmitter. Also copy “Voice” folder with two fvoicefiles to Apps/Voice. Head on to “Applications” -> “User applications” and add the app. Guide on installation of Lua-apps available here if you need some more in-depth guide.

App is also available in both App Managers, JETI Studio and Jeti App Manager.

Setting up WindSpeed

After installation open the app and you are presented with easy setup with only a few options:

Settings are quite clear, give the app sensors for Airspeed and Groundspeed, announcement-switch is optional. After this power up the model so app can recognize both sensors, when both sensors are online and valid app stores the unit (km/h or mph) to model memory for logging purposes. After this you need to power down the model and re-activate the app, simplest method is to select another model in your transmitter and come back or simply restart your transmitter. After this your log-files will show a new value “Windspeed” with correct unit like m/s or mph.

Using WindSpeed

Simply add a telemetry-window to your screen:

After a flight you can also open your log-file to see the results:


As you can see in the example above the windspeed is negative. That means headwind. A positive windspeed would mean tailwind ie. the model get’s help from the wind for faster speeds. (Looks like small bug in transmitters log-drawing with negative values.

Version history

  • 1.0 Release version


Some rules do of course apply!

  • Never use Lua to control a function that would take the model down if misbehaving!
  • Always, always test the function thoroughly before flying!
  • If you do not know, then don’t!
  • RC-Thoughts or myself is NOT responsible for anything this application does
  • Applications are free to use (MIT-license) and linking to this page is encouraged!