An update on my project (please see my previous two posts).


This is a screencast of APM2 running in HIL mode with the X-plane RC plane in an 8kt wind over a simple course, takeoff, circuit including loiter, land, fully auto (radio not touched). In JSBSim/SITL results are actually better than X-plane HIL which has poor resolution and slow sensor update.


If anyone wants to try this firmware, in X-plane or in HIL or SITL *please* let me know. I would like testers.

I can build it for APM1, ardupilot-mega and APM2 boards or of course there is the desktop version for SITL

I'll upload the source to a git clone soon as well.


My plan is to fly a skyfun and/or skywalker with it when the weather relents.

features so far:

Same base code as ArduPlane, but new navigation, stabilize and autopilot PDEs






WAYPOINTS and the normal mission planner stuff


mode switching

Auto-trim - boot with elevator stick at top of the range and plane will fly a short routine to self-tune as soon as you hit AUTO mode.

Presets - presets for several different kinds of UAVs

More free memory

Trig lookup tables to free up cpu

50hz navigation

GPS extrapolation

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  • Hi ,I am a newbie,I am using sitl,but facing "no link" when testing.Who can tell me why is it? Thank you!

  • Hi Justin

    Are you still working on SITL, I wanted to simulate different wind conditions ?

  • Justin, great project!  Any test flights yet?

  • @Justin

    *please* I would love to test the HIL version for APM1 & APM2 Xplane.

    How can i test your HIL version?


  • In the sim everything works well :)

    however I'm now buried up to my eyes in the group efforts to improve some of the support libraries which are critical for providing accurate sensing. Of course in the sim we have perfect information. I hope to get out with test flights as soon as the work on the library fixes slows down. I've got at least 3 planes of differing types to try.

  • Hi Justin!

    Do u have some positive results with your wind-resistand code testing? 

  • The git clone is available

    As it stands it is setup to build HIL firmware, or JSBSim SITL desktop version (from autotest)

    To build actual flying firmware for APM2 (which I do not recommend you do until I've had a flight or three)

    you would edit APM_Config.h a little, to define or not define APM_HARDWARE_APM2

    and to comment out the XPLANE definition, turn back on logging etc.

    the stuff above in readme.txt. on the config values, also applies.

  • UPDATE: Here are a couple of firmware images

    one for APM2 hardware and also the Oilpan

    the other for APM1

    I'm working on my git clone, so anyone wanting SITL or actually to fly this firmware for real has to wait for that to be up

    Anyway here are the HIL firmware images:

    and the readme

    If have an existing X-plane/HIL setup you should be working in minutes.


    Flash the hex file


    Change UAV_PRESET depending on the type of plane you want to fly in HIL.

    See readme.txt for details.

    That's it. You can experiment with varying wind, the LAND and TAKEOFF commands etc
  • here is a video of the Bixler X-plane model, which cruises very slowly, in wind with turbulence as well. There is no setting in X-plane for wind from a constantly changing direction but its turbulence setting causes variable wind as well as gusts up and down etc.

    for the middle part of the video I forgot to move the camera and map around to give a more interesting view, sorry, but the last minute shows the landing approach ok.

    You can clearly see the constant attitude changes to keep on track.

    The turbulence setting of X-plane is quite tough for tiny models, unrealistically bumpy and gusty for a setting of "1".

    The autopilot bixler config ran actually on the same settings I had for flying the X-Plane Cessna. I bumped aileron and elevator gains because it is a slow plane, with a lot of stability, and changed the cruise speed and it flew the circuit.

  • I don't want to release an image, only to update it 60 minutes later with an improvement. For example later today I'll get the bixler x-plane model I'd like to test it against that.

    Hopefully in the next two days I'll post either the firmware images, or the git branch, or both.. sorry for the delay.

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