I want to first thanks to all developers for this fantastic codes. And this forum give me a lot of information during my built. I have just switched from quadplane configuration to conventional tailsitter one. The project is supposed to become commercial product in the future. However, at this moment, I must first get to know all relevant tailsitter design principles and software. I want to share our first transition test flight with Arduplane 3.8.2 with mostly default parameters. (But I have just seen that 3.8.3 has been released today, will try it later for smoother transition)
From flight log, we’ve found that the control surface size is too small causing the aircraft to tumble in pitch many times especially during lowering throttle while hover and windy condition. However, I think it could be able to stabilize itself back every time due to excessive thrust to weight ratio of this vehicle, more than 2. I still use EKF2 (Not EKF3). Airspeed sensor doesn’t work properly in FBWA too. Will check it later
Here is the link for dataflashlog (incase you guys want to check it):
Has anyone tested using larger motors and propellers? Would 12"+ props work if you got a stable enough tilting mechanism?
Also, in order to scale this design, could you mount two motors per side for a 4 motor system and run the motors from the same ardupilot motor outputs (parallel).
[quote=“rubiksman, post:795, topic:15302”]
Has anyone tested using larger motors and propellers?
[/quote] yes this one uses 14" props https://youtu.be/koOqenMpvck
I’ve been continuing to test RealFlight8 models for @lorbass. He is building a model of his caipirinha TVBS. I’ve created a separate discussion topic for it so everyone can follow along if they want to, or get involved with building a model https://discuss.ardupilot.org/t/building-realflight8-models/23106
Has anyone ever testet TVBS with ONLY TV and no control surfaces? I wonder how this would fly.
Maybe someone is willing to do some tests with disabled ailevons? Would do it myself, but I don’t have vectoring.
I tried it in RealFlight and it flies fine at high speed, but if you slow down too much in fixed wing then things go very badly, as you lose control completely.
Hello sir, good experience, I also experienced loss of control at lowering throttle for vertical land, and loss control in windy conditions.
Can you please take flight test by increasing controling surface and please share your results.
thanks for all the hard work guys,
Is there a post or wiki with all the relevant up to date info on vectored bellysitter setup?
Nearly 800 posts of info is a whole lot to parse through.
I have successfully hovered my plane, however the throttle response was very low in the belly land position, if I stand up the sitter I have enough thrust to hover. Edit: Found post about Q_A_ANGLE_BOOST
What am I missing to get mine to transition from belly down to tail down takeoff?
Also, what is everyone using for log overlays? Dashware?
Just before I did an endurance test which went absoluty fine.
This is what happend now:
Seems as if it wanted to fly knife egde… Have not taken over controll till about 0:40 (!!!)
I put it on the ground and it was fully initialized. I switched to QStabi and armed, then put in Auto mode.
After this wired flying happend i first switched into FBWA with full thr, but wasnt changing anything. Then i switched to QStabi and it was able to get in controll again. Then switched to FBWA again which went fine with transition. Flying towards myself with backtransition and landing safely.
This is the log from the test before with no problems. I only adjusted FBW PIDs while flight a tiny bit, so they might not be in the log correct. Everything else is same both flights. https://www.dropbox.com/s/us41wtcvpmixcbd/00000011.BIN?dl=0
unfortunately that log is completely empty. No msgs at all.
Do you have a tlog from a ground station for this flight?
that log actually shows some quite severe control problems, plus quite bad vibration. It oscillated over about 20 degrees in pitch while in LOITER mode, plus the vibration was enough that the DCM attitude estimate differed from the EKF estimate by about 30 degrees at times.
I’d suggest adding more vibration isolation (and mass) to the flight board, and then doing an AUTOTUNE of the fixed wing tuning parameters.
I suspect the bad flight is just a worse example of the same sort of issues.
Cheers, Tridge
I had my android phone connected via QGC, but there is no file I can find on it.
Yeah on the beginning of the flight I had bad ozzilations in pitch. Then I adjusted the pids a bit (higher d) and the were not visible anymore from gnd.
The PIDs I used are results from Autotune though. Seems not to work well on my plane, because it its aerodynamically unstable. (CG is very far back)
In FBWA its flying Ok.
Just noticed that this log is faulty also, I was flying 17 min, but log stoped more early.
[quote=“tridge, post:806, topic:15302”]
plus the vibration was enough that the DCM attitude estimate differed from the EKF estimate by about 30 degrees at times
[/quote] Whats DCM? Which params do you compare here?
Might be. I will repeat this test.
Did you check AUTO in SITL?
Also it would be awesome if we find a way to restore my PIDs for hover. Before your patch they were perfect.
I think I calculated them at full throttle (100%). So now my hover thr is at about 0.7 (70%)
100/70= 0.7
So I calculate my PIDs: “New = old * 0.7”, right?
Are all (P + I + D) scaled like this? Whats with FF?
I enjoy watching your videos as I lurk on this thread. Two questions: 1) what is the incremental weight (in grams, or % of AUW) of the tilt hardware relative to a non-VTOL, fixed motor version of the same wing? 2) I can tell on landing, but do the motors tilt skyward as the wing flops to belly? Or do you simply cut the motors as soon as you have wingtips on the deck, and belly slightly inclined toward resting position.
Sorry if the answers to these questions are obvious to those following this interesting thread more closely.
Hey Tridge and everyone else. Thanks for starting this thread and posting the information. I’ve just started building a dual motor tail sitter, so I’ve found the information in this thread valuable. I started my first fixed wing VTOL 3 or so years ago, a wing/tricopter mashup, only to discover that there was very little support for transitioning, so I was really excited to see how far things have progressed. Cheers! -David
