I made more flight to test RTL (as a flight mode only) with q_rtl_mode=1.
I do not use home but rally point instead.
When rally point altitude is set to 20m, RTL works always as intended.
When rally point altitude is set to 40m, transition location depends on the altitude and distance (from rally) when RTL is triggered. I mean low altitude (bellow 20m) and short distance from rally make the transition to happen shortly or immediately.
So I believe that transition happen outside rtl_radius only if the plane cant reach rally altitude before entering the rtl_radius.
That sounds a clever way to manage RTL !
@losawing , my last WP before Home is 120m dist. & 25m alt. and ALT_HOLD_RTL = 1500 / Q_RTL_ALT = 15 / RTL_RADIUS = 15 and Q_RTL_MODE = 1.
Since this last WP there is rate of descent to reach RTL_RADIUS but it makes the back transition in this last WP.
And I have noticed testing values with SITL & RealFlight that this happens when I choose an excessively low value (<1) for Q_TRANS_DECEL
Hi @iampete , Windwaning for Dual Motor TS? 
@marco3dr has already tested it successfully with some beta… 
Yes, it works very well but the code still needs improvement because it causes unwanted behavior during transitions.
There will also be a marked improvement on the transitions, @iampete is working very well on this thing and the tests i am doing on Realflight are very promising.
At the moment imho it is better to avoid automatic missions and QRTL with non-vectored tailsitters, the results, even if well parameterized, could also be disastrous.
We are discussing it on Discord, in the quadplane channel, I have posted a lot of videos.
I have personally stopped my tailsitters on the ground until these improvements are indisputably tangible on the SITL.
Many things in the code that NOW are good for quadplane are absolutely not valid for tailsitters, its flight envelope is a separate thing.
OK, @marco3dr thanks for the comment. Yes, I have the same problem, the back transitions are successful, that is, it is well parameterized, except in AUTO and QRTL modes. In these modes sometimes randomly the tailsitter destabilize and oscillate in the descent phase after finishing the transition.
@iampete ,thanks you for your work
what is the name of the channel on Discord?
It is for developers, so it shouldn’t be used for help, but you can read it anyway.
no compass is needed any more…unless you want to start missions in vtol mode…ekf aligns with GSF after gps vel readings occur and works well from then on…you can lift off in vtol position hold modes,but it will wobble around until yaw aliignment occurs, or you canarm, walk the vehicel around in acircle until you get ekf3 active, and set it down and start a vtol mission…
I dont fly many vtol missions but just takeoff in qstab and transition to fw…can do qloiter and missions with vtol land after that
First Hover tests of my Z84,
omnibus f4 aio
camera/vtx aio 200mw
frsky XSR
20A blheliS running oneshot 125
2300kv motors with 6x4 propellers
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@Iosawing, the promise is a debt, after this mission flight there is any better landing. I would like to send one better video but I can not play it. I have to test Disk Gain but weather is not good.
Sitting Bull is a teamwork, four good friends
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Thanks for the video. Flying auto with a tailsitter is not something straightforward, congratulation to the sitting bull team.
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As you said, Tailsitter DM is a small kingdom but great at the same time
Yes I know, my answer comes verry late.
After a long trip via Tri Tilt VTOL, Copter Tailsitter and other projects I’m back to the roots as Dual vectored.
And after reading hundreds of the last posts, I can react.
As you reported, there is a roll-oscillation with all my test flights. But without experiance in Plane I
thought this is a bad tuning.
Is this meanwhile solved?
This is the big problem with non-vectored tailsitters, landing.
Unfortunately Ardupilot for obvious reasons cannot realize when the tailsitter touch the ground in a reasonable time, the throttle drops too slowly and the flip occurs.
To avoid this for the moment I have set a switch on the tx that puts the throttle to a minimum, so here the motors are stopped, forcing MANUAL mode, so that the propellers stop as soon as possible.
It seems to me that those of the Wingtra to avoid this thing have put a small lidar on the tail.
Another idea that came to me since I mount ESCs with BLHeli s to find a clever way to activate the reversal thrust at the right time to anchor the tailsitter to the ground.
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I havent flown that one in quite some time…but I know I got it flying well…cant remember the fw roll issue any more…sorry
Need an advice on non vectored dual motor tailsitter tuning. We are testing a new plane with AP 4.1, flight and hover is good with default parameters. My build is AUW 800g, 2212 motor 8x4.3 props. 1500mAh 3S, Matek F405 Wing, no airspeed sensor. It hovers at about 50% throttle in QSTABLIZE.
- In transition from plane to VTOL, it tends to climb too much, 10-15m, need to descend a lot which tailsitter is not good at. How can I improve?
Seems to me too much throttle is applied? I see new param Q_TAILSIT_THR_VT will be introduced in 4.2, any workaround in 4.1? Better to have airspeed sensor?
In this video, I set Q_TAILSIT_ANG_VT 45, Q_TAILSIT_RAT_VT 70.
Thanks in advance.
4.1 does have some tailisitter back transition issues…they are still being worked on in the dev branch but several improvements, like that parameter, have already been merged into the dev branch…