Don Montague tells us about aspect ratio, profile depth, wingtips, lift drag ratio, tow point position, center of effort and lots more. You will also see some of the power a kite can handle when Don use them to pull 5 man canoes. You may also hear that he is already on to the ultimate depower concept that the crossbow kites have given us today. You may want to watch it several times. I know i did :-)