T-Rex 450 on a 15 Waypoint Mission

APM 2.0   firmware 2.7.3

MediaTek  and barometer  no sonar

As promised last time, here is another successful mission with a T-Rex 450.

The day looked very good for flying, but as we arrived on the flying field the wind picked up very much with gusts.  Despite the wind I flew anyway, because I had a friend with me who also flies T-Rex 450.

After the mission was successfully completed he was very much impressed how the little heli mastered the mission and how well the APM performed. He actually considers now to fit his heli with an APM.


The Heli was flying pretty much on track; the altitude was sometimes off by about 4m.

You have always to see things in scale; this condition was for the little 1kg heli like to fly with a Robinson in gale force wind.


All the mission flies, log files and parameter files are in here:

T-Rex 450 on a 15 Waypoint Mission

So you can review the mission in your Mission planner.



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  • Yes i did just 1houer ago thanks for that. Will check it out soon if the weather gets better.

  • Now that is a really neat anti-vibe mount idea!  I've seen earplugs used, but they're always glued which I don't like.

    Check my comment in your thread about the Tilt parameter.  I noticed you already have it set at 32, it defaults to 54.  Did you change it at some point?

  • A big issue for success are getting the vibrations under controll. Check all your bearings. I use an “earplug vibration damper” like this in the photos. Just pull an earplug thru a 5mm hole, it will regain its shape in no time and locks itself firmly in.  

    You can even adjust the firmness of the damper by changing the distance between the two plates, by pulling the earplugs more or less thru.




  • @Lefebvre

    Yes if I look at this from the loiter perspective then you are absolutely right, there might be something wrong.  Great, thanks for pointing my thoughts in the right direction on this one.


  • Awesome !

  • In retrospect, there really should not be that much speed error.  The navigation controller should pull back and fight the wind.  If you can loiter in that wind, you should be able to hold proper speed in that wind.  Simple as that.

    I am having a hard look at this, because it needs solving.  My heli hit 90 km/h when it was actually commanded for 18%.  That's a 500% error!  Something is wrong.

  • I actually have a big self-made gas Heli, but I think it is too full of vibrations for the APM.....


  • Yes my eyes are at a T-Rex 800 for the future....

    But the little thing did very well. You have to see things in perspective. Yes there is a 100% speed and a 80% altitude error, but if I choose 90km/h and 100m the error would be only 10%.

    Airliners drop some 100m and have 10km/h speed errors.

  • You need a bigger heli! ;)

  • The speed is Km/h. Yes I know it’s about double the set speed at the tailwind leg, he was pushed along by the wind quite hard.

    At waypoint 10 he was supposed to loiter for 10sec, and you can see he was pushed down and backwards by a wind gust. It’s hard to find a calm day in our area. :-)

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