This has been verified once again.
May 11, 2025: Vibe test with two weighing scales, like years ago, and with similar results. This test consisted of attempting to see the values given by the two weighing scales at the same time when possible, and then to observe the evolution of the pulling force on a single weighing scale throughout the trajectory in eight then also the trajectory in loop.
A peak of 4.5 kgf on both weighing scales simultaneously (9 kgf in all) was achieved during a short gust (about 6-8 m/s), and during the flat part of a large figure-eight towards the middle of the flight window.
Then (with slightly lower wind) a regular (as expected) traction force of 3 kgf plus 1 kgf was achieved on very tight loops (about 3 m in diameter like in the old video of Low radius loop that showed the traction force on a single line, with the second handle having been released and the two lines wrapping around each other).
Then the wind did not exceed 3-4 m/s: during figure-eight, traction force on the same weighing scale of maximum 2.5 kgf and about 1.25 kgf on the other weighing scale exactly at the same time, these values being reversed during the trajectory.
On the same weighing scale, the traction force varied from 2.5 kgf to less than 1 kgf, partly due to moving closer to the edge of the flight window where the kite loses its power, partly due to the change of the global traction force during the trajectory, and partly due to the sharing of forces on the two lines (unlike SkySails’ kite which operates with a single line). The outer side of figure-eight or loop experiences more traction due to the greater speed compared to the inner side, and in a proportion depending to the amplitude of the trajectory and its curved (more difference) or flat (less or no difference) part.
