Dual-motor tailsitters

Hello everyone. Where is the ideal position to place the autopilot in a vectored thrust craft?

Does it have to be smack bang in the middle of the cog or can it be little forward or aft of the cog

I don’t think location relative to the CG is critical for attitude control, and I would expect it’s not important for position control either.

Can anyone upload a latest parameters for non vectored tailsitter Plz.

Hello Syam,
In my humble opinion I think it is better to understand and deepen understanding each parameter. It can be a bit tedious but it is more beneficial in the long run. A copy & paste can be counterproductive for your model

I have read all the 2k comments for the last 4days and set the parameters…but qhover and qloiter its not behaving as the way needed . Because iam using Skydroid rc…there is no proper trim options…

This thread resume some basics :

I started with non vectored, and changed to vectored because of bad experiences.

And when you read all posts, you may noticed that not many others hat good results. To unstable especially in wind.
For qhover or qloiter or Copters you do not need trims at the TX.

Guys my plane is moving towards right side continuously and horizon is showing flight is rolled to right…
When i turn stick to left , both horizon and flight came to level . When released again moving towards right.
Why this happens. Flight was in stabilize mode.
Its non vectored

Did you calibrate the Radio?
https://ardupilot.org/plane/docs/common-radio-control-calibration.html

When you have an issue you need to post the .bin file from the flight controller.

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FX-79 Hello friends. I fly the FX-61 in the tailsitter configuration, with your help I managed to achieve stable flight and transitions. Not so long ago the FX-79 came, I installed more powerful SUNNYSKY X3520 motors and RDS3115 servos on it. The files for printing were kindly provided by lorbass, for which many thanks to him. The following problem arose: the FX-79 refuses to hang stably, oscillations occur along the pitch axis and I cannot defeat them. Tried different PID options. Who faced this problem and how to deal with it? Could it be the servos? My config file:FX-79.param (21.1 KB)

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Loving TVBS!..my latest…and smallest…and most efficient so far…
needs a little more tuning…

next I have a NIB s-800 I want to convert…it will be even a bit smaller in wingspan, 800 vs 845mm but I dont think it will be as efficient…

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That looks great! What deflection can you get on the motors with that design? It looks simple and lightweight. I wonder if it would avoid some of the gyroscopic torque issues that a direct tilt servo mount has…?

Approximately +/- 45 degrees

I managed to make several flights with my FX-79

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Looks cool !
Could you tell us more on AUW / Flight time is you have already it. You run X3520 520 Kv on 6S i guess, which prop are you using ?

I am using SUNNYSKY X3520 KV720 for 4s. For testing, propellers 13x5.5 mm were installed. I plan to use 15x8 propellers, which should fit from day to day, then the flight time will be known…

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@Leonardthall @tridge @priseborough Trying to fine tune my Z84 TVBS above…it has a constant, steady 1hz oscillation in roll in FW modes…Tridge and Pete Hall have been helping me try things: zero i, increase i, zero the new slew limit RLL2SRV_SRMAX=0, zero out Q_VFWGAIN …I have rewired to make sure cables are loose…nothing affects it…its not aliasing, since it happens in zero throttle glides…I have bench tested throttle slowly ramping with no effect on horizon or mag/x/y/z…I have never run into this before on planes…about to conclude its a defective y gyro and replace the autopilot… here is today’s log after zeroing SRMAX and retuning…this constant slow sinusoidal wing rock really messes up video

Is there any slop at all in the control linkages? This can be caused by zeroing problems in your servo or movement in your control linkages or the hinge of the flap. The symptom to look for is does the flap return to the exactly the same position from full deflection in both directions?

no the elevons are tight and driven by digital ball bearing servos…its not control surface slop…
the tilt mechs are tight also, and are not involved in FW attitude since VFWGAIN is zero