Best method to limit elevon throws during loops?

I have a new FIMI Manta VTOL flying wing. I have run Autotune, and it flies great in FBWA and Acro. However, in Acro, it tends to roll out of loops unless I am very careful not to pull back too much on the elevator stick. In manual mode, full elevator gives a deflection of 30 degrees, which seems like a lot. I see three ways to limit elevator deflection in Acro, and I don’t know which is appropriate to the problem:

  1. Lower Acro_Pitch_Rate. I have the Manta, HeeWing Ranger VTOL and Xiake VTOL, and all three came with Acro_Pitch_Rate = 180. The Ranger and Xiake loop with no problems, but the Manta rolls out. I tried lowering Acro_Pitch_Rate to 150, and saw no effect. I don’t see how to tell on the bench if this changes elevon deflection. I can hold the elevator stick to full deflect and change it’s value, and sometimes the elevon moves, sometimes it doesn’t. Maybe the plane has to be moving to see an effect, since we are talking degrees per second?

  2. Reduce the elevon servo endpoints. All three VTOLs came with elevon endpoints of Min 1100 and Max 1900. I could change the endpoints on the Manta to limit elevon deflection to say 20 degrees. But I don’t want to interfere with FBWA or RTL. And if I take this route, must I redo my Autotune?

  3. I could run Autotune again with more aggressive stick movements? Is autotune supposed to adjust rates to accomodate loops and rolls?

So how should I limit servo throws so that my Manta will easily do good loops in Acro Mode?

Thanks, Doug


Mixing_Gain is currently set to 1.2, and Mixing_Offset is set to 0. Should I try turning Mixing_Gain down to 1.0 to lower elevon deflection?

How would that differ from lowering Acro_Pitch_Rate?

OK, you were right. I turned MIXING_GAIN down from 1.2 to 0.85, and the loop problem is gone.

@mutski Just wondering I just got my Manta -FC and wish to use a SBUS receiver. Any thoughts on how that hooks up, if you know? I think from the limited info I received I need to solder my Rx inputs to the pads on the bottom and change the bord Type…