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#21
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Where to get Winched?
On 8/06/2012 00:37, Bill D wrote:
If you're only getting 33% of the rope length, yours is a low performance winch operation. If you optimize it, 45% or so is achievable in no-wind conditions. A 10 knot wind can boost that over 50%. Again, I'm saying this is for gliders with better than 30:1 and rope tensions equal to the weight of the glider. Below 30:1, achieved height falls off a lot. I didn't say it was "my" operation and I don't mind your 'low performance' putdown, Bill. I've been involved in eight different winch operations and my judgment overall is, like Chris said - 400m from 1200m, about 1:3 is a normal nil to light wind figure. I've read previous posts on this from you. I think your 45% minimum is optimistic and you do winching no favours making those promises. 1. The vast majority of winch operations are hand to mouth. Old winches launching old gliders. Most of us can't afford professional winches costing the price of 2 Pawnees. Most winches (outside Europe) are medium- to low-powered. About 1:3 is what they'll get. An aerotow operation converting to a winch probably won't be a prosperous, thriving club setting out buy a $100,000 Skylaunch. 2. The vast majority (ALL, in my experience) of winch operations are optimistic in their claimed launch heights. "He's not a very experienced driver". "There must be a tailwind at height". "This is not our best launching direction". "The engine is due to be serviced". "The wire's a bit shorter than we usually have". I've heard them all - including (just now) "...if you optimize it...". I believe YOUR operation will routinely achieve a little better than 1:3 but will rarely exceed 2:5. GC |
#22
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Where to get Winched?
On Wednesday, June 6, 2012 6:38:19 AM UTC-5, Walt Connelly wrote:
Where in the South East US of A might one go to get a winch launch endorsement? ALSO, in general how much runway is needed for an adequate winch launch? What might the minimum runway length be? Walt -- Walt Connelly 1:3 jibes with what we get at Boerne Stage (5C1) doing winch launches off 4300 runway. 1400 feet AGL is the common height achieved for the Grob 103. |
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