Twin Stability

Twin triangular box kites were rigged on one line, one in the top "pilot" position, the other further down the main line connected to a tri-swivel by a short leader line. The rig was flown in several sessions in different conditions. To make an "accelerated" flight test as rough as possible, the kites were flown in a strong turbulent urban (empty lot) surface wind.

Twin kites are a minimal array and this testing found the basic effect of aggregate flight stability, but less so than more kites in an array. The upper kite seemed more stable than the lower, seemingly due to a "bowstring" effect jerking the lower kite more. A normal lock-out event that would crash a single kite was usually prevented by the second kite. Seldom did the kites synch in a loop and crash, rather, off-phase flight dominated. When they did crash, they always hopped right back up in a successive gust. The twins tended to self-relaunch sooner than one alone, as the first to rise took the other with it. Chaotic double-pendulum dynamic was damped, and the chaos greatly suppressed.

Over grass or sand surfaces, such kites would be fairly robust, and could be relied on to fly whenever wind is present. The kites sweep crosswind naturally in a good breeze, enhancing their lifting power. Fighter kites develop keel in a blow and stabilize, but these boxes go more and more nuts. Some sort of passive reefing or damping would be nice. KiteLab, Ilwaco, WA. Dave Santos

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