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Permalink Reply by Glenn M on June 11, 2012 at 4:36am

I've had quite a few problems trying to get my APM1 to control my tricopter (delrin kit) well. Haven't really had successful loiter, and if it can't do that I'm not even going to try auto missions, so even though APM has those features I wouldn't rely on them actually working. Have crashed plenty of times, sometimes due to APM and don't even really have any original parts of my delrin kit left intact. I've got a cheap multiwii board which feels much nicer to fly the tri with. 

One annoying thing about the delrin kit is the arms flex a lot since you can only use 10mm size wood, and I think this has been the source of some instability. I've just rebuilt from scratch today with plywood centre plates,after the delrin frame plates broke in an APM related crash on 2.6 delta. This lets me run 12mm square arms which seem to be a lot less flexible than the 10mm ones. I'm running the yaw mechanism from rcexplorer.se's tricopter v2.5 which is much more durable than the delrin kit one which broke in my first low alt crash onto grass, and is less wobbly. I have just zip tied all of the motors onto the arms.

Others have had some success with APM2 and tricopters it seems though.

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Permalink Reply by Mica on June 11, 2012 at 5:27am

OK, thanks for your comment.

i want to focus on APM2 on the software problem instead of delrin kit frame : I prefer to have good and reliable controls, than a lot of features and options (autopilot, waypoint, telemetry..).

As i said above, the hardware of APM2 seems perfect for me, the price also is affordable.

I would like really to know if the tricopters problems i read on forums are fixed now.
If not, if tricopters are not fully supported by APM2 - I mean "Ok APM2 can fly tricopters, but as it is not done for this especially, you can have some problems" : I think i wont buy.

Hope some people can tell us their experience with tricopter and APM2.

Thanks.

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Permalink Reply by Bruce Jones on June 14, 2012 at 3:33am

I'm a couple days ahead of you Mica.  I just recently added an APM2 to my Delrin Tri and have had 2 batteries worth of flight with it so far. My thoughts from that evening are on this thread.

I hope to get out again tomorrow to do more testing.  So far, results are a mixed bag for me but I have high hopes to get things working well.

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Permalink Reply by Glenn M on June 14, 2012 at 3:41am

Have you managed to get your tricopter vibration free? I had the delrin kit and used 35cm long 10mm square pine arms and I had no end of problems with it. I think the 10mm arms are just too thin and flex too much to provide a stable platform. I wasted pretty much 2 months trying everything I could to get it flying well without vibration, everything was perfectly balanced etc, but it still vibrated.

I had a crash recently which snapped the lower tray mounts off the lower delrin centre plate, and so I ended up having to make my own centre plates out of plywood (you can't buy replacement delrin frame plates individually), and set it up for 12mm square wooden arms which are cheap and easily available. I made them 40cm long, and the difference between the stability of this new setup and the old is night and day. The 12mm arms hardly flex, and as a result, everything is smooth, and my video is nice and clear and crisp.

I would recommend ditching the delrin centre plates ASAP and making yourself a frame built for 12mm arms. You will save yourself a lot of time and pain. I also got rid of the delrin yaw mech as it didn't perform well. Any slop in the servo was amplified in the linkage. I'm running the rcexplorer.se tricopter v2 yaw mechanism now which bolts directly to the servo spline, and it is rock solid and stands up very well to crashes (unlike the delrin one).

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Permalink Reply by Mica on June 14, 2012 at 7:20am

Hi Bruce,

Thank you for your reply.

I read the other topic, and i understand that you got a normal behavior with apm2 and delrin tricopter after hours of parameters tuning. Because of the yaw. This is not what i want to do i think...if i tune the code, this is not to fix the board tricopter code.

Anyway i still have not chosen my board.

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Permalink Reply by Bruce Jones on June 14, 2012 at 9:39am

Actually, I haven't tuned it all yet.  And it flies pretty nicely.

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Permalink Reply by Mica on June 14, 2012 at 1:29pm

Hi,

Really? Even with the non perfect yaw behavior?

Ok i checked again the link above, and the person who replied to you at the end said that his law problem is almost fixed, and he spent times on parameters tuning.

To sum up today, on APM2, the yaw and the gps is not perfect.

My nx 4008 motors are going to be shipped by hobbyking,i still have few days to make my choice. Paris, ardupilot, KK, OpenPilot...etc Select the flight controller board is definitively the most difficult part.

Do not hesitate to keep me (us) informed about you next tries.

Thanks!

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