Nice… I did not know about that option. I will try it very soon. I need to fix some minor issues with the plane first. I will keep you posted.
Anything on my end to try?
I believe E-stop, like you did, is the best option for now. Just cut the motors when it contacts the ground and it won’t be able to fight the forward tilt.
@losawing I’m not sure I understand your question about bellysitters.
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Look at the landing at the video end. the belly sitter go from vertical to horizontal without bouncing despite non commanded attitude change
Right, I was forgetting that “bellysitter” meant TVBS.
I believe the difference is that the bellysitter is at an (unstable) equilibrium point in pitch when it touches the ground on landing, but the blackfly sees a strong pitch moment resulting from the ground contact. This provokes a strong reaction from the control loop and things go unstable.
I know this is a different controller/firmware, but I wonder how they take care of the landing issue:
I believe quadplane firmware will behave that way in QSTABILIZE mode.
I was referring to their blackfly landing process (how it does not bounce). You mean land in QSTABILIZE?
Yes, there’s a simulated landing in QSTABILIZE at 2:27 here:
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Fascinating… I will give it a try.
I can not fly at the moment. I tried using the SITL software with quadplane model and it landed without issues using a waypoint mission that I flew previously with bouncy landing. I then realized, the quadplane model is most likely not modeled after a blackfly.
I looked for the BlackLetpi_EA.RFX file but it is no longer available . Can you repost the correct link to download and try it?
Thanks
That RealFlight model and parameters are here:
It flies for me in QSTABILIZE, QHOVER and FBWA on latest master (and should probably behave the same on stable).
But the tuning could probably be improved in both VTOL and FW modes and the altitude control in QHOVER seems a bit weird.
Thank you very much. I will most likely be spending a lot of time with this model. My plane is out of commission again.
So, you expect the blackfly to land properly without bouncing in QSTABILIZE mode (per the simulation). However, when I do a waypoint mission, how can I achieve a similar outcome? I don’t see any options to set QSTABILIZE when landing (VTOL_LAND or QRTL).
I don’t think there is any way to avoid the landing problem in AUTO modes.
I am having an issue running the simulation. I loaded the mission planner “flightaxis” model with plane. Then, loaded the param file you provided. I then created a simple waypoint mission and loaded it. When I arm, only the rear motors turn and the model flips upside down on the ground.
Since months I wanted to see what vertical acceleration I could get out of my jetwing
bat 5S 40C
5" pitch prop
Qstabilize mode
disk gain attenuation method
0 to 100 km/h in 2.7s
more than 4g initial acceleration
unfortunately qstabilize mode limits average motor output to around pwm 1700 so motors can not spin as hard as they can and speed can not get over 35m/s
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Does it fly OK in QSTABILIZE mode?
Bravo… 
I wonder how much motor PWM margin you need for yaw stability?
Does the jetwing have a rudder?
no rudder,
The right/left balance seems to be very good but the bottom motor is running a little higher than the top one. Stability provided by motors is needed only at low airspeed.