Criteria for Aspect Ratio of Motor Positions of the QuadPlane

ArduPlane VTOL Plane
1

I am planning a building of a QuadPlane.

If Aspect Ratio of Motor Positions
= Distance between lateral Front motors vs Distance between Front and Rear motors
= Lateral distance / Longitudinal distance,

for my best knowledge, aspect ratio of motor positions is ONE for the ideal configuration making a square.

However, we need a rectangle configuration having an aspect ratio of motor positions more than one due to a fixed wing geometry. That is, the lateral distance is longer than the longitudinal distance.

My questions are:

  1. Can the QuadPlane support a longer lateral distance to have a value of 1.34 (134%)?
  2. If yes, what parameter adjustments in Q mode are required for stable Q mode flght?
  3. For a rectangular quad shape, what is the maximum ratio acceptable by the QuadPlane logics?

Thanks

2

My frame type is X. Q_FRAME_TYPE=1

3

Many multirotor frames have that geometry w/o much consequence. “Squashed-X” or “Deadcat” are a couple. Slight reduced Pitch Authority is about the only issue and many may not even notice that. I would think that QuadPlane is analogous to this. I guess is could be more pronounced if the thrust/weight is relatively high compared to a multirotor which is common.

4

Plain vanilla X works for most X-like geometries.

5

Thanks Dave.
I feel the same way. It is of interest whether it is possible to quantify the influence of the aircraft when it is a rectangular X shape.

6

It will be clear after tuning. I had a couple of Deadcat like frames with one very distorted from an X and the Pitch and Roll parameters were quite different. But, proper tuning can handle that.

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