T-Rex 600E with APM2 - Test Flight

As requested, here is a clip of one of my test flights with the APM2 on my 600. This may be the most boring video ever, but in this case, boring is exciting! The APM2 works amazingly well mounted on Align gel, where a tail gyro normally sits. Stabilization is very good using  these parameters, though I need to lower the yaw values since there's still just a bit of tail wagging.

I've had this bird for a couple years, so unfortunately I think there is a bit of play in the linkages, and a couple of the servos have sticky spots. This causes small variations in the rotor disc (leading to slight wandering) which the APM is not responsible for.

The previous stabilization system I had was a Robbe HeliCommand. Absolute rubbish. That caused more grief and wasted time than I can imagine. Although, I was terrified of tuning it and knew very little about the effects of vibrations, so maybe it was good and I didn't know it!

Either way, APM2 + TRex is awesome so far.


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  • Hi guys, i´m totaly new to this, and have a question to you all pro´s.

    I have a brand new Align 600 EFL Pro whith 3GX on board, and want to be able to FPV and take photos and video from my heli.., i use a FY-30A on a fixwing plane so i am a little familiar whith stabilization gyros.

    So my question is, can i use APM2 together with 3GX ? Or should i only use APM2 ?


    Best regards

    Soren von Perner


  • That looks good! And I'm happy to say it looks to be about how well mine performs, too. Did you have Alt_Hold on for much of the video? I've had decent luck with it (holds within a meter on average) just with default params. However, I imagine there is plenty of pressure variation under that rotor, so it's not always a perfect hold.

    I'll keep trying things regarding yaw speed. It does seem a bit counter-intuitive the way tuning works for it, but hopefully I'll make some progress. 

  • Eric, I'm not entirely sure, but I don't think you can directly control how the yaw speed maps to the stick input. I'm trying to figure this out myself.  However, yesterday in my testing, it seemed to be influenced by Yaw Stab P.  I'm running it about 2.5 right now.  I'm looking at the code and that appears to be the case, though I don't know if it's by design, or "just sort of happened that way." 

    Anyway, shot another video yesterday.  I tried to do some hands off hovering but there is a bit of wind so it didn't work out too well.  I also did some close-in hovering to try and show how well the tail is holding.  The bobble when I touched the ground was I believe due to engaging Alt_Hold.

  • I'll give mine another try with the compass to see if I can tell any difference. Where do you have your board mounted?

    I do have a sonar but I haven't installed it on the heli yet. I don't know how well I like it from trials with my quad. It seemed to work sometimes, and not others, but I'll let you know when I try it with the heli. For now I've been tuning the yaw to get the last jitters out. How do you adjust yaw speed? Mine takes its sweet time turning a few degrees. I was thinking the Rate term would be key, but I'm still lowering it to get rid of oscillations. What are your Yaw terms?

  • 3 more good flights.  I turned the compass back on and... still crap.  Really don't know what to do.

    Eric, have you got a sonar?  I have been fighting this so long, I just can't get it to work.  The signal is crap.

  • I just zeroed my Stab_I terms, and turned off the compass, and gave it a try. I can't say that I see much of a big difference. On the other hand, I've only had a few flights total, so perhaps there is a good difference and I'm just not familiar enough with it to tell. Regardless, it still hovers quite well both ways as long as the wind isn't shoving it around.

    I also switched from my Spektrum to the Turnigy 9x so I can tune things easier. Had to re-do a few settings to get it back in working order, but everything seems to work well.

  • Yeah, the compass seems to create all kinds of problems for me so far.  I needed to tune the yaw loops without that confusion.  I got the yeah REALLY precise without the Mag interfering.

  • Good info, Robert, thanks. I'll definitely get rid of the Stab_I and see how that works. What sorts of problems are you having with the compass? I haven't noticed anything bad so far with mine. I only had a throttle-yaw correlation when I had the board on my quad, but on the heli it seems to be fine. I guess the gyro does a good enough job with heading hold without the compass, huh?

    Thanks for the video too, I appreciate seeing what other people are doing, since it seems there are very few of us with helis let alone 600's!

  • Novice.  Experienced with airplanes, but pretty novice in heli.  I am not even hovering nose in yet.  I can do it in the sim, but still too scared to try it live...

    And keep in mind, I consider that hover "bad".  The other flight I did was better.

  • Nice video, could see a bit of drifting.. Btw how would classify ur traditional heli flying skills ? Novice/experienced /competition levels :). I shall admit that I am novice
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