[altermac]

Hello!

I'm building a tricopter, better said i rebuild this one: I learned the hard way, that motor 1 (NW) should have CCW-rotation and motor 2 (NE) should have CW-rotation.  In reversed Rotation for all motors the tricopter tends to fold up at higher throttle, wich not the best flight condition. So this time motor one will be CCW and motor two the CW.

Now i have only one motor CW-rotation left for the tail (motor 3, S), but in GCS the third motor always rotates like motor one. I can't reverse only one motor in GCS, only all or nothing.

Can i use a reversed tail-motor without changing it in GCS? The tricopter will yaw to the right instead of turning to the left without correction.

Has anybody flown this configuration?

CCW - CW
       +
     CW

Thank you in advance for your comments.

[altermac]

After a successful maiden flight, more hovering than flying, it seems that this configuration works fine. Hovering is stable at one point in the air, no wobble, no turning. Yaw left/right works without problems. Switching between full throttle / low throttle in hover works fine, copter does not turn or wobble. I used the Standard Tricopter model for default values with the wizard.

So my conclusion is: Motor 1 (front left) must be counterclockwise-rotation, motor 2 (front right) must be clockwise-rotation and rotation motor 3 (tail with servo) doesn't matter. And this is not because the Librepilot needs it, it's because a folding tricopter will fold the arms back at full throttle if you do it the other way.

Thanks for listening, sometimes it helps telling it to someone else.

[hwh]

The folding arms just snap into position and aren't pinned?  That does seem like it could be a problem.  Although, in a crash you'd have a 50/50 chance that it would just fold instead of breaking I guess. 

[altermac]

In common designs you have one screw for the axis and another in front of the arm to block the arm in position and pinches the arm between the to plates of the frame. With the right motor-rotation the arm moves in direction of the blocking screw. This is the design David Windestål (rcexplorer.se) uses.

I use a 3D-printed frame and startet with CW-CCW-CW. As the arms folded back first time, they were only pinched by the frame. Second time i screwed the arm in position with another screw, so on full throttle one arm rips of parts of the frame.

Some frames, like HK Talon or HK X900 use Screws to fix the arms to a channel on the frame. I don't believe that they can stand a powerful motor.

If you are lucky enough to zero throttle in a crash, the arms fold nicely without killing any props  .