Radio Failsafe and compass setup

I received my iris today and got it flying, but I have a few questions that I would like to iron out.

  1. The radio that comes with Iris seems to be shipping with a PPM receiver. I havent opened up the shell yet, but the transmitter is configured for PPM. As far as I can tell, the radio cannot be set up for a failsafe condition when it is in PPM mode. This seems quite dangerous for this type of aircraft. Am I correct that the radio shipped with Iris cannot be set to RTL on radio link loss?

  2. When I first started flying, I could not get the loiter mode working properly. It would start drifting off to the side as soon as I would hit the switch, even though my GPS location looked solid and I had a reasonable HDOP (1.5 or so). I also noticed that my compass heading was quite erratic. I tried re calibrating it and it didnt seem to improve any i tried changing the device from the APM with external compass to the pixhawk internal magnetometer, and then it started working properly and loiter and waypoint navigation started working properly. Is this the correct setting or am I doing something wrong? It seems to work ok, but it looks incorrect to me.

All in all the quad flies very stable and the autonomous navigation is impressive to see. Thanks for the help

here is a video from the flight after the compass change was made.

Since the FC on the IRIS is a Pixhawk, selecting the Pixhawk/PX4 in the compass calibration page is the correct way to go.

ok… that makes me feel better…

Also, after opening the top cover, I realized that the failsafe programming button is on the Rx, not the Tx as I am used to. The failsafe is now set to RTL as it should be…

I think this is a critical feature that needs to be documented somewhere. the Iris documentation is clearly targeted to a novice audience, which are more likely to push the limits past where they should be. Might want to add it to the next rev of the manual.

It have a few questions on the video as a new pilot etc…

I noticed when you started your mission you were at 27% battery sing this below the recommended level for LiPo ?

Also your voltage dropped below 10.5v and RTL didn’t trigger, did you set it lower or disable ?

I am recovering from a crash so have not tried waypoint to a camera yet so just trying to learn


you have a good eye…

I had been getting used to waypoint programming and switching the quad to auto, so I had been doing a few short runs like that. Take off, do a few waypoints within 10 meters or so, RTL and land, all of these flights were just a minute or two, which is why the pack was already fairly depleted when I took off in that video.

Technically that voltage and discharge level wont hurt the lipo, but you better be close when you start hitting the last part of that discharge curve. Once you fall below around 10V, you are pretty much out of charge and better be on the way home.

And you are correct that the battery failsafe kicked in at about 10.4V, which happened right as it was descending for landing. I edited the video just before that happened. At first I was confused why it stopped descending and started going up again. It was because it was programmed to RTL on low battery voltage.

Ah ! Good to know.