Hey All,
After several crashes, a couple of my motors sound different when I spin the props by hand. The quad (Iris+) is also much less responsive than my Phantom in vertical maneuvers especially. Is the Pixhawk in my Iris smart enough to compensate for a weak motor by throttling the others down to match?
If so, is that something I can see in the logs?
Thanks
kw
Arducopter can mask issues quite well at times, it does compensate within the limits of your system.
Log with RCout enabled, a weak motor will show as a higher value than the others.
I finally got some time and no wind to test the RCOUT logging.
Attached is an image of a 4 minute flight that was almost all hover climb and land with ALT Hold and Loiter.
I’ve never seen another log to be able to detect what a problem might look like.
Does this look normal to you?
Thanks in advance.
kw
there is a very slight imbalance in clockwise to anticlockwise motors, that could be a slight twist of one or more arms.
But in general to me it looks under powered/over laden. 1700 average between motors at hover too high in my opinion, this is exacerbated by the imbalance…channels 3/4 are 1800 ish at the end…they can only go up to 2000 ish max!
I am not surprised its sluggish.
I like 3DR, but I have seen a few under powered iris’s, I am not certain as I don’t have one or have ever seen one in the flesh.
If one motor was high and the others low could indicate a problem with one, but doesn;t seem to me that in this case.
Thanks again for your help with this.
I was flying again the other day, it was a little windy and the quad wasn’t doing well, even in loiter, so I landed, disarmed, re-armed and just idled on the ground with just enough throttle to keep it from flying. Then I dis-armed and re-armed again and flew. It started to really act weird so I just landed and shut down. The log though I think shows what you were talking about. Channel 3 is consistently higher on the ground and especially at the landing (almost another crash).
What do you think?
Here’s the end of the flight.
yup, that last plot really doesn’t have a lot of power margin, not enough for safe flight.
Check motors are level as I suggested, this will hopefully buy you a bit…but I think it will till be under powered.
subscribed, and anxiously awaiting the results. I have some ideas, but am far too new to the Pixhawk, to start babbling. I’m playing with two Iris+ machines. One with gimble and GoPro3 black, and the other with a cheaper GoPro “Hero” mounted directly to the front. I’ve had my up’s and down’s, but both flying very well. LOT’S and LOT’S of adjustments and tweaks available, and very easy to screw things up big time, “IF” you don’t know what you’re doing. That was my main reason for buying a second Iris+, one to experiment with, and one to leave stock, sort of 
I have some 10/4.5 props on order to play with.
Thanks Again for your help.
Now I just need to find replacement motors.
3DR doesn’t seem to be able to process any orders right now.