As you can see, this is the beginning of a toilet bowl, which - left unchecked - will crash.
Took my quad out tonight, after going back to 2.9.1. First few loiters, everything was ok. Even did a few RTL's. Everything looked like before.
Until the last two loiters - my toilet bowl was back! At first, I thought it was because I had tried to tighten loiter a little (P from 0.2 to 0.4). Fair enough I thought. But I set it back to 0.2, and the toilet bowl was still there!
Now admittedly, I still have all my 3.0.x mods on - mumetal, ferrous rings etc, but I didn't think loiter used these in 2.9.1. Some investigations required here. Well, they're all coming off tonight, and I'll be back out tomorrow with the airframe absolutely identical to pre 3.0.x. And my logs set to raw + motors, as tonights were still set at factory default so missing some important data2013-07-07%2020-47%2011.log. Doh.
Unrelated annoyance: Had two props take up lawn mowing on take off tonight; one leg had snagged in a weed! So important tip; if flying from grass, make sure your legs are unsnagged. Another fun evening with the spirit level re levelling my arms as as consequence.
Comments
The link for using the external mag is here.
http://copter.ardupilot.com/wiki/common-external-magnetometer-for-i...
Jesse: Yes. Just need to cut a trace (which is designed to be cut, so it's pretty easy). We'll post a tutorial tomorrow.
Toilet bowling is almost always due to magnetic noise. Once you move your APM up or use the new remote mag solution with 2.6 it will go away.