I am hoping someone could maybe give me a few ideas on some problems I have been having with my new build:
2014 3DR Quad Frame Kit
3DR APM 2.5 w/external compass/gps (trace cut on APM board)
3DR 880Kv black motors
QBrain 4x20A ESC (all calibrated)
4S 5200mAh liPo battery pack
10" x 4.7 APC Props from 3DR
The apm was on an older 3dr quad, so I reset everything to factory defaults and started over. I also upgraded to the latest non-beta firmware today which is 3.15.
I have done all calibrations(accel/compass), compassmot shows 11%, vibrations are low and I am still fine tuning the pids. I did try auto-tune a couple times, but after calibration was done and I had tried the new settings, my quad would wobble like crazy, totally bad settings.
I've noticed that the motors get very warm, almost too hot to touch. Today I was testing out RTL and just before it touched down, less than 3ft from the ground one motor(front right) went completely out, no power so it ended up flipping over. After removing power then plugging the lipo back in, everything is fine, motor starts along with the rest without any problems, I did a short hover and it's fine?
I attached the log from todays tests, I am wondering if I should be going with better esc's, maybe 30amp ones? Possibly different props like possibly CF 10x4.5 ones? The motor temps I am not used to , most the time with my other quads the motors are warm, but not to the point where these ones are.
If someone could please take a look maybe someone can see something I missed, I would really appreciate it.
I had started another post a few days ago from here: http://diydrones.com/forum/topics/3dr-2014-quad-frame-kit-pid-settings
Replies
Just wanted to post an update to my problems I have been having.( and I have been getting some help from 3DR support)
Im summary after working on this for weeks on end what I am finding out is that the black 880kv 3DR motors I am running on my 4S setup are just over their power limits with the configuration I have, same thing with the 3DR 20amp simonk esc's(I would have to run 30amp ones and even then the motors are at their limit still), this is why I have been having issues with trying to use autotune, it's also why no matter how much I try to tune it, a small gust of wind and my quad is all over the place, can't add enough I to save it's life.
Most of this became apparent when I went from 10x4.7 SF APC props and changed over to GF CF 10x5.0 props, you could just hear it trying to maintain flight, and yes I tried re-tuning it.
It's totally flyable only on calm days, no wind, my other quads with the apm, not even an issue they all run great and have no problems when there's wind.
Two possible solutions
1) Going to a better quality motor, say a TM MT2216-12 800kv, which would more than handle this quad and resolve the issues.
2) Getting 3S 5000 or 6000 mAh batteries and keeping the same setup, less runtime however.
At this point I have already spent too much time and money, and I had assumed that 3DRobotics "kits" were more thought out than this. Anyways live and learn I suppose.
My flight with a 4S 4000mah battery, the motors were warm but not hot.
https://www.youtube.com/watch?v=5Ua6K-CyOW4&feature=youtu.be
I know, I know, there is Yaw control for turning :-)
LOL, actually I understand that, if I was in an area like that I would be doing the same thing :)
Looks good!
It is flying really well, I still need to test RTH again but I am a little worried. That area is usually pretty breezy, over that hill is the ocean so it can blow pretty good at higher elevations but it performed well.
Just wondering, but how does it do when the wind gets going? I know that testing RTL with mine and the wind kicked up, it was all over the place, I had to switch it off in order to get it back under control..
I will have to wait for that, I usually ground myself when the wind picks up due to the cost of a crash ;-). I will take it to a really thick grassy area next time it is windy and see what happens.
I just got done with a couple more flights, it's doing pretty good, however I am noticing that wind starts to really mess with this quad unlike my others, I did try to fine tune it a little but didn't make much of a difference, of course I was flying around 250ft in the air at one point, it seems to really get kicked around.
I am thinking maybe going with CF props, I am using the APC ones now on this quad, on a similar quad I have with another APM I don't run into these issues and it's using CF props, have to wait and see.....
Here is the video that led me to believe I had some other issue, this was first flight after installing the black motors. After the first run there seemed to be a problem with motor 2. I did resistance checks on the ESC and they check out, I am now going back to check all connections and solder joints.
https://www.youtube.com/watch?v=8fJDtBG5kUY
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