A few tries today and the illusions are gone. The (only) two wings attached in crosswind flight (see photo and video below) are uncontrollable, even for less than 1 second, due to the linkage acting as a hinge.
On the contrary the rotor which is on the previous video and the photo below turns very well.
A good pilot kite has a L/D ratio of 2.4. This does not give much room to increase lift, which amounts to increasing the angle of attack (on a 4-line kite we play with the 2 brake lines) and further reducing the L/D ratio. See also the discussion on Using a lifter kite as a low aspect ratio power kite.
I imagined some means (see the sketch below) to increase the lift coefficient, but the mentioned tests just above do not encourage me to go further.
That’s what I would have thought. Yet it is a flygen system that uses high lift multi-element airfoil: High lift coefficient and biplane kite and kiteKRAFT fly-gen kite flew figure-eights.