QuadPlane Turning Inquiry

Good Evening All,

I represent a design team at Virginia Tech that is currently working towards fabricating a custom QuadPlane for a competition we participate in. Our competition relies heavily on waypoint accuracy and obstacle avoidance, thus we have a question regarding craft yaw control during transitions.

The way our missions and flights are set up, we require the craft to yaw using the multirotor before flying to the next waypoint. After playing around with a simulator for countless hours, I was unable to find a param that allows for this ability. Ideally, we would like that after loitering at a waypoint, the craft yaws to face the next waypoint (similar to in ArduCopter) before transitioning to a fixed-wing. This would allow for the craft to have a very small “turning radius” and allow for us to fly tight maneuvers.

If anyone can point me in the direction of getting this working, any help would be appreciated. Also, if this is currently not capable with the current firmware - I highly request that a parameter to be added as it would aid us heavily in our current and all future crafts.

Thanks in advance for the help!
Manav Gandhi

Hi Manav,

Since you are using a QuadPlane, you could try this process.

  • Fly to Waypoint 1a as Plane
  • Switch to QuadPlane hover mode and fly to Waypoint 1b (see note below)
  • Add new Waypoint 1c near current position but in desired direction of travel
  • Travel but mostly turn to new Waypoint 1c
  • Switch to Plane
  • Repeat sequence to next Waypoint

Note: Switching from Plane flying to QLOITER mode may cause breaking issues or oscillations so you first switch to QHOVER, let the plane slow down, then switch to QLOITER and it will stop on exact position. Waypoint1a-Waypoint1c, etc. are actually multiple Waypoints in the mission plan near the same location.

Hey Greg,

Thanks for the quick response and your help. I understand why switching from Plane to QLOITER mode would cause breaking issues or oscillations, but is the same true for autonomous mode. If we were to have a LOITER_TIME command within the mission - with a WP_LOITER_RAD of 200ft with the craft flying at 35 mph - would this not be fine? Just to clarify our Q_GUIDED_MODE parameter is set to 1, so the fixed wing will transition to a multicopter at all LOITER commands.

As per the steps you have provided, they seem to help with getting the YAW to face in the direction of the next waypoint - but not all the time. Right now my mission is set as the following, the craft does not fully YAW before moving on to the next waypoint.

LOITER_TIME (Waypoint 1a)
LOITER_TIME (Waypoint 1b)
LOITER_TIME (Waypoint 1c)

*Waypoint 1a and 1c are the two target waypoints, while waypoint 1b is the additional waypoint added in for turning purposes.

Thanks for the help!


The quadplane mode changes do not account for all types of designs. While some quadplanes may work without extra steps, others may not be as tuned or have strong enough power systems. In other words, one mission plan does not work for all vehicles.

In your steps, you need to position Waypoint 1b so that you can draw a straight line between 1a and 1c. In other words, Waypoint 1b needs to be far enough away from 1a to complete the yaw change.

These are just suggestions on my part as I have not had the need for such critical turning position. Be sure to look at the Q_WP Parameters like Q_WP_RADIUS that affect how your quadplane responds to autonomous commands.

Good luck!


Thanks for all the help. I guess I will leave this fine tuning down to when the craft is actually up in the air and flying. If I understand correctly, there is no param similar to in ArduCopter where I can just have the craft yaw to the next waypoint.

If this is true, I highly request that a developer adds this into the QuadPlane firmware - as it would aid us and many others in our flight planning and waypoint accuracy.

Thanks for all the help!
Manav Gandhi

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