Date: Tue, 30 Nov 1993 03:44:41 -1000 From: R.J.Green-SE1@cs.bham.ac.uk (Robin J Green) Message-Id: Organization: School of Computer Science, University of Birmingham, UK Subject: Bridling (again) "Oh, he's going to crack open that old chestnut again." I hear you complain. Well, yes I am, so there. I have been playing with this very bog-standard parafoil design I have built, (12x4 bridling points and no idea where the lift vector of the cross section actually is) trying out different bridles at great personal expense in lengths of dyneema line. I have come to some conclusions. 1) Any bridling system I can think of has to be symmetrical, and as such has three 'minimal' states where all stresses are equalised. a. With the bottom surface flat (for a flat bridling), the kite stable and flying all peachy. b. With the two halfs of the bottom face pressed together, the kite folded in half, hanging all sad and jittery in the wind. c. With the two halfs of the top surface glued together, the kite folded in half, hanging all sad and jittery in the wind. All things being equal, the ratios of outcome given normal launching methods are about the same. Bummer. I think this cascading thing business needs to be rethought and I need more control on the angle of attack and the lateral flexing of the kite... , the ... Hey, I know what I mean. And cross bridling makes for WONDERFUL unknotting puzzles, especially in high winds, which is when you really need to unknot anything. 2) These experiments were done in the best and most regular windy place I know - the pedestrian tunnel below a very tall tower block. Just take two steps left and Vwhhhhooommmm you're in a roaring regular flat gale, two steps to the right and you're back in a light, easy wind making landing no more than a gentle trot forward. You don't get that on exposed headlands! - Robin Green. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =