KITE TRACTION Some theory. For kitesailing and especially for buggying (because of higher speeds) the important determinant is apparent wind not actual wind. Apparent wind is the vector sum of true wind (speed and direction) and buggy/kitesailer velocity and course, but only when the kite is in steady state flight, and not turning or weaving. Interestingly, when the buggy/boat speed is much higher than the speed of the true wind all courses become upwind courses. If you find this relationship hard to understand, consult any reasonable book on yachting for a more complete explanation. The consequence for buggying/kitesailing is that for good performance (except when going downwind slower than the wind) the kite(s) you use must be able to get well "around the edge" and technically the angle "around the edge" that a kite will hold in steady state flight is determined by its Lift to Drag Ratio (L.D.R.). 80 degrees corresponds to an L.D.R. of 5.7 this is at the high end of what currently available kites can manage and still compares unfavourably with yacht, land yacht and wind surfer sails. High L.D.R. is, unfortunately not the end of the story. For good buggy/boat velocity the kite must be able to get well around the edge and retain good pull when it is there. A simple way to get more pull at the edge is to use a bigger kite but this approach is severely limited by the tendency for larger kites to generate uncontrollable pull when not "at the edge". What we need is a big kite with "M.M.R." approaching 1.0. "M.M.R." stands for Maximum/Minimum pull Ratio and is the ratio of the maximum pull (for a given wind speed) that a kite will generate (usually occurring when the kite is climbing at maximum velocity and is directly downwind from the flier) to the pull available when the kite is hovering at the edge. The future of buggying/kitesailing is hostage to our success at developing traction kites with L.D.R. above 6 and M.M.R. much better than available from existing kites. To confuse things further there is an exception to the requirement for low M.M.R. Another way of thinking of M.M.R. is the rate at which line pull increases with increasing apparent wind. For most buggying and kitesailing we can best use a kite that develops usable, close to maximum pull at low apparent winds but with, ideally, negligible increase in line pull as apparent wind increases from that threshold. For out and out top speed high M.M.R. is acceptable provided long run-ups are available. Theory predicts and I have often experienced situations in buggying when smaller kites or kites with high M.M.R. (e.g. Flexifoils) will eventually enable high top speeds. This will also occur in kitesailing when we start accomplishing speeds above, say 1.5 x windspeed, as the apparent windspeed component generated by buggy or boat speed becomes the significant part of total apparent wind. Of course, as discussed later, the kite's available top speed is a limiting factor.