The kite design was based partly upon having heard of (but never seen!)
single skin paragliders, along with some drawings of highly undercambered
airfoil shapes documented in a model aircraft journal.
Correctly or otherwise, I reasoned that the flight envelope of a buggy engine requires high lift at low speed and high angle of attack. This seemed to me to resemble the landing configuration of a modern aircraft wing, with slats on the leading edge and trailing flaps.
My kite has these slats and flaps, with an extremely high aspect ratio main panel between them. The foil shape is maintained by conventional ribs, with the slats and flaps attached by extensions of them. The bridling is very complex, combining a single point radial outer section each side, joined by an arch centre section, with longitudinal semi-arch bridling for the brake lines. This feature eliminates the trailing edge curl seen in so many other 4-line foils, and enables the entirely novel experience of flying a soft foil smoothly backwards across the window without the trailing edge collapsing.
It flies extremely well at low speed, take off is effortless in winds where a similar sized quadrafoil needs a very firm tug to lift it at all. The shortcoming in the design is the way the outer front corners tend to close up and flap around at high speed. I am working on fixing this problem.
John Travell.