My copter keeps rising in Loiter mode

Hello, maybe I do something wrong but I can not figure out what it causes. First I wait for a gps fix, (got 12-14 sattelites). Than I arm my copter and fly away in Stab mode, this works very well. Than I switch to Loiter say on 10mtr , not touching the control sticks but slowely the copter rises from 10m to 12 to 15 o 20??? I have the throttle stick in the middle. I use the apm2.5.2 and arducopter v3.0.1, the barometer is coverd with foam and the motormot gives 17%. What do I wrong? The RTL works great, my copter lands almost on the same spot as where it took off :slight_smile:
Please help.


I am no specialist, but I have experienced similar behavior with my quad.
It might be that your barometer is off or not covered well enough.
My copter would go down slowly if in LOITER, but not always.

check that the cover over your barometer is sufficient.
otherwise check first in ALT HOLD mode.
this will exclude the GPS

octofly Hilversum

Have you got any throttle trim in your TX?

I check but I did not use throttle trim.

I had a similar problem in Alt Hld and Loiter, all I did was adjust the throttle stick till it stabilised and it has been sweet ever since.

Did you adjust it in althld and loiter or in stabmode before switching to one of these modes?

No logs are posted so it’s hard to be sure but the two most common causes of rising or falling in loiter mode are:
#1 - the throttle stick is not in the middle. sounds silly but it’s very easy to do if you’re switching from a manual flight mode (i.e. stabilize) and your copter hovers below 40% throttle or above 60% throttle. You can adjust the manual flight mode’s mid throttle with the THR_MID parameter. It’s documented on the wiki here.
#2 - vibration. Instructions on how to measure vibration levels are here.

Thanks, I will try these options. The THR_mid could be the problem, I changed my motors 1120 to 750kv and the props 10x4.5 to 11x5.0 so maybe the mid isn’t correct anymore.