Can not have a thrust differential in after transition toFBWA

ArduPlane
1

Hi there, I am very new to this community. Hope someone can help me out.
We are building Flying wing VTOL using APM3.8.2. Setting Frame class to 7 (Tri) , frame type to 10, with vector yaw. Tilt servo 75/76. Two front motors =33/34 and the tail motor = 36.

As our plane has no rudder to corect yaw from uneven thrust from two front motors when transition to forward flight. The thrust differential control should be the only way to correct yaw for tailess aircraft. We have gone through the parameters but cannot find it. I must be missing something.

I see FiresFly6 VTOL which is quite similar to what we are trying to make and wonder how it correct the yaw from uneven thrust.

It could be some parameters I have not set.
Thank you very much

2

You can apply differential thrust with rudder using RUDD_DT_GAIN
http://ardupilot.org/plane/docs/parameters.html#rudd-dt-gain-rudder-differential-thrust-gain

3

Thank you, Roft,

We have set RUDD_DT_GAIN to 50%. After fully transition to FBWA, we gave rudder input from our flight box. We could not see any change RPM on 2 front motors.

We can see the effect of this RUDD_DT_GAIN in 2 cases

  1. during trasition (not yet fully transition)
  2. When servo function is set to 73/74 for the front brushless motors. But the motors did not spin when it was in tri copter mode.

We have to set the servo function of motor 1 and 2 to 33 and 34 to get tricopter working. During transition, seems like RUDD_DT_GAIN is working and it ewas gone once it fully transitioned.

Thank you very much

4

I have just done a fix for this.

Would be great if you could test it, I can compile the code for you, what flight controller are you using?

Thanks

1 Like