3dr 2014 X8-RTF Loiter Mode Question


I had my X8 out in some frigid temps this morning and after taking off in stabilize I switched my Spektrum Dx7s into Loiter Mode and climbed to about 350 feet. I then tried to descend the X8 in loiter mode but the throttle didn’t seem to respond. I had the throttle below 50% with no response, then slowly worked the throttle to 40% all the way to 0% without any response. I finally had to throw it into RTL to get it to come down and land safely. I didn’t lose GPS or anything ala no beeping on the video, any idea what the deal is? It was 5 degrees out with no wind. Any help greatly appreciated. :smiley:


Videos are nice, but tlogs and/or data flash logs will give the most accurate indication of what went wrong with your multicopter.


Thanks, I’ll have to learn how to make logs, I’m sure the info is out there on what to do and I’ll learn how to do it, thanks. :smiley:


I download a the data flash log from the flight in question. Please see the attached RAR and thank you very much in advance! :smiley:


Those logs (the .bin and the .rar) show you ascending in Alt Hold mode, the uav reaches 100mtr and triggers a fence breach and RTL is engaged just before the tree line. About 30sec after that, the throttle is dropped below 50% working it’s way to 0% as the uav comes in for landing at which point rc channel 5 (flight mode) is changed but has no effect due to the fence already triggering RTL.

Hi Markm,

Thank you very much. So I was hitting an altitude fence? I started trying to review my own graphs but couldn’t understand some of it even after watching tutorials. I certainly was in Alti-mode ascending up when I thought I was in loiter. Would really dig to know which graph in Mission Planner shows this info or how you correctly concluded your analysis for my own education.

So essentially, when you hit a fence the drone stops responding?

Thanks again for your time!


Your log shows FAILSAFE_FENCE-1 which is altitude fence. You’re fence limit is currently set at 100mtr alt and 300mtr radius and you got up to 100mtr alt and triggered the fence. Your current action is set to RTL or Land, and plotting your log against the map it went into RTL mode as it flew home from the tree line and when it got there it started to descend.

Version 3.2.1 of arducopter has a change to the fence so that when you hit the fence altitude it won’t go any higher but will still let you fly around. Perimeter still RTL’s as far as I’m aware.

When I opened the log I chose the “Baro” menu on the right, then ticked “Alt” and clicked the box above all the log info marked “show map”. Resized the map to make it a little smaller and you will see the graph show your altitude, what mode you were in, and where the fence kicked in. If you double click on the graph the map will focus on where the uav was at that point in the log.

You can also double click on the blue flight path on the map and the graph will change to that point as will the log information below the graph.

HI Markm,

Thank you very much for the info and help! :smiley: