Odd RTL during auto missions [ Solved - Sort Of ]

I finally have my Skywalker X8 quadplane flying well. I’ve run in to an odd issue with RTL behavior. When I do a simple circuit and trip RTL when it’s far away and heading towards home it works just as expected. It’s amazing to watch.

However, I set up a couple of mapping survey grids with Mission Planner and at the end of these there is a RTL command. When that command executes at height the vertical motors come on, the plane sinks and then rolls over. It was easy to recover by switching to FBWA but I did two different grid surveys and it happened both times. There’s a log here if anyone can help out.

Looks fine to me, VTOL motors don’t come on till it is 100m from home

Hmm, could be the wrong log as the plane actually rolled completely over when I put it in RTL. We did a lot of flights on that day. I’ll go out and recreate the issue and be sure to post the correct log later this week.

Took it out for more test flights and couldn’t fault it. Darn thing is flying great!

Hi Darrell, I have ever seen your X8 Vtol video on youtube some time ago. Good to hear your X8 performs great. May I know your AUW in kg? About RTL in mission, I also did this test but still not sure at what altitude the plane change to Copter (QRTL) mode for landing. What is your RTL altitude? For long range, I plan to have very high RTL for safety reason, but the problem is, it will change to QRTL at very high altitude which is not good.

The AUW is 6.5kg with payload. I use a RTL altitude of 30 meters but the plane rarely descends that far before it gets back so I’m thinking of adding a rally point with a lower height. However, I had a friend suggest I try putting in a waypoint and changing to ‘loiter to height’ which will fly the plane in a circle while it descends. I believe there are some new features coming regarding VTOL landing options planned for this year.

Recently I’ve been landing manually with a fairly standard fixed wing approach and then switching to QStabilize when it’s about 50 meters down from where I want to land. Then as it floats by and slows down I switch to QLoiter to lock it in place. Then I just lower it down. This way I can get it to about 10 meters off the ground as it comes in which saves a lot of vertical battery power.

Look at bit 4 of the Q_OPTIONS…and new VTOL landing wiki page