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For Christs sake Bill! Lasham is the largest and most professional gliding
club in the UK and we do about 10,000 winch launches per year, 9,999 of which go without incident. We do know what we are doing. We either point the glide directly at the main winch, or just slightly upwind of it in a crosswind to reduce any initial yaw due to weather cocking. The K13 incident was caused by a gust, and the glider was landed without damage or injury. A similar wing drop during an aerotow would be considered quite unremarkable. The correct thing to do is to pull off if a wing drops during a winch launch. Derek Copeland At 03:42 26 June 2009, bildan wrote: On Jun 24, 7:00=A0pm, Don Johnstone wrote: What is particularly interesting in both the video and the photographs is the direction the glider is pointing relative to the cable. In the video the glider can be seen to yaw as the cable tightens and then further yaw as the it starts to move. In the photographs it is clear that the glider is pointing to the right o= f the direction of the cable AND stangely is pointed in the same direction = as the K13 parked behind it, a co-incidence perhaps. In both cases it would appear possible that the glider was not lined up with the cable prior to launch so that as soon as the cable moved yaw was induced. With a CofG hook the glider will be more unstable about the yaw axis than was the cas= e with the more forward release on older gliders. Perhaps that might explai= n why this appears to be a "new" phenomenon. Nope, they lined it up at an angle to the wire then all the other stuff compounded the problem. There are other videos from Lasham with the gliders improperly staged which show a similar wobbly takeoff. If the gilder isn't pointing at the winch, the takeoff will be 'interesting'. Unfortunately, some people in the US are showing the k-13 photo sequence as proof that winches are too dangerous to use. This actually forced me to add a paragraph in my winch training syllabus cautioning pilots to aim gliders at the winch - which any kid launching a balsa glider with a rubber band would understand without being told. To be fair, there very well could have been a wind event that we, in a dustier climate, would call a "dust devil" which couldn't be seen in lush green England. We would see it coming and stand down until the thing passed - then launch and go chase it for the lift it marks. |
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