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#141
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SAFE Winch Launching and automatic gearboxes
Chris,
Nothing special required, except that the rollers or pulleys should be smoothed out and polished if they have been used for steel cable. Some types of drum may need to be reinforced as Dyneema can slip and tighten on the drum to the extent that it get crushed. What type of winch do you have? Derek Copeland At 23:50 22 July 2009, Chris Nicholas wrote: Has anybody in the good old US of A developed a printed, available, specification for the pay-on gear for Dyneema etc. rope =96 like low weight (aluminum? - note USA spelling!) rollers, low friction and low inertia bearings, anything special needed for the drum , etc.? I suspect that there is scope for saving inventing too many wheels twice over. (And for the avoidance of doubt, I am NOT going to get into the Bildan/ DC/DJ etc. spats =96 you are all welcome to keep those among yourselves.) Chris N. |
#142
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SAFE Winch Launching and automatic gearboxes
Thanks for answers so far.
Derek, we have two ex-ATC winches (Eagle or Wild – not sure which), re- equipped with USA-made V8’s and auto gearboxes. Both run on LPG or similar. One has a completely new cab, the other a modified cab. We bought the basic winches in about 1991 at auction, cost less than £1000 (say $1600) each. First was modified by ourselves at very low cost, with an ex-Ford Tow truck 5.6L V8 and associated auto transmission. The second we used a winch-builder at another gliding club who had built their Tost winch, and he modified ours including new big V8 and auto transmission, and the completely new cab. I think we spent about £14000 on the conversion, and completed a bit ourselves at very modest extra cost. Chris N. |
#143
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SAFE Winch Launching and automatic gearboxes
Chris Nicholas wrote:
Thanks for answers so far. Derek, we have two ex-ATC winches (Eagle or Wild – not sure which), re- equipped with USA-made V8’s and auto gearboxes. Both run on LPG or similar. One has a completely new cab, the other a modified cab. We bought the basic winches in about 1991 at auction, cost less than £1000 (say $1600) each. First was modified by ourselves at very low cost, with an ex-Ford Tow truck 5.6L V8 and associated auto transmission. The second we used a winch-builder at another gliding club who had built their Tost winch, and he modified ours including new big V8 and auto transmission, and the completely new cab. I think we spent about £14000 on the conversion, and completed a bit ourselves at very modest extra cost. Chris N. I can add that I've launched from at least one of those winches, and had very nice launches. Probably down to the driver, though there's clearly nothing wrong with the winch(es). Hint for US clubs who go for a winch - pilots should always thank the winch driver for good launches, and explain what went wrong if a launch is not satisfactory. This feedback helps the driver to improve, and also means that your own foibles might be catered for in future launches! Poor launches are often the pilot's own fault, and winch drivers like to know that it wasn't their poor driving. |
#144
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SAFE Winch Launching and automatic gearboxes
On Jul 22, 5:50*pm, Chris Nicholas wrote:
Has anybody in the good old US of A developed a printed, available, specification for the pay-on gear for Dyneema etc. rope – like low weight (aluminum? - note USA spelling!) rollers, low friction and low inertia bearings, anything special needed for the drum , etc.? I suspect that there is scope for saving inventing too many wheels twice over. (And for the avoidance of doubt, I am NOT going to get into the Bildan/ DC/DJ etc. spats – you are all welcome to keep those among yourselves.) Chris N. Yes, I have and I'll send anyone the CAD files free. The unit has been built and tested on an old Gerhlein winch and it shows no degradation of the Plasma Rope. |
#145
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SAFE Winch Launching and automatic gearboxes
On Jul 22, 12:48*pm, tommytoyz wrote:
Bill, How much did the Gehrlein overhaul cost? Perhaps this could process can be replicated several times over. My guess is that once small scale winch launching grabs a foothold via Gehrlein winches and it becomes more popular and more pilots get winch certified, that demand will grow and we'll see the need for more productive multiple drum winches. Perhaps we can then use the Gehrleins as retrieve winches at that point. Launch costs can be brought down so low, as to stimulate soaring in this country. I myself am tired of paying $50 for one single aerotow - it's nuts. Nothing will stimulate soaring more than to bring the costs down and winch launching not only does that but makes soaring more challenging and fun too! I know, I'm preaching to the choir. So, choir, we need a cheap initial solution to get things moving - to demonstrate and get people certified - before we can realistically talk about expensive, albeit more productive, winches. Tom I've worked pretty hard helping small winch operations get going with refurbished winches. You're right. Once people get familiar with winch launch, they'll want better equipment. |
#146
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SAFE Winch Launching and automatic gearboxes
On Jul 23, 12:45*am, Derek Copeland wrote:
Chris, Nothing special required, except that the rollers or pulleys should be smoothed out and polished if they have been used for steel cable. Some types of drum may need to be reinforced as Dyneema can slip and tighten on the drum to the extent that it get crushed. More spectacularly bad advice from Del C. Smoothing and polishing rollers will NOT work since the rope slides in a helical path on the roller if the wrap angle is not exactly at right angles to the roller. All roller designs used with 'plastic rope' show rings of melted plastic when used with Plasma Rope. The rope itself shows severe damage from melting. Using rollers with Plasma Rope is an expensive mistake Plasma Rope (Spectra/Dyneema) should have swiveling pulleys with specific pulley groove geometry. I have a tested design for fairlead pulleys with a Plasma specific guillotine that I'll let anybody use to make their own. E-mail me and I'll send the drawings. |
#147
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SAFE Winch Launching and automatic gearboxes
On Jul 22, 11:16*pm, Frank Whiteley wrote:
On Jul 22, 6:38*pm, sisu1a wrote: On Jul 22, 4:50*pm, Chris Nicholas wrote: Has anybody in the good old US of A developed a printed, available, specification for the pay-on gear for Dyneema etc. rope – like low weight (aluminum? - note USA spelling!) rollers, low friction and low inertia bearings, anything special needed for the drum , etc.? I suspect that there is scope for saving inventing too many wheels twice over. (And for the avoidance of doubt, I am NOT going to get into the Bildan/ DC/DJ etc. spats – you are all welcome to keep those among yourselves.) Chris N. While I'm sure there *are such documents handy, if your goal is 'saving wheels' one can (and is better off...) doing away with the level wind mechanism altogether, which is itself a source of additional hassle in most operations. The trick is to use a high enough aspect drum and have a long enough run between the fairlead assy and the drum, somewhere around 1:18 I believe, comparing drum width to run length between the two mechanisms according to German DAeC. Assuming a bigblock/TH400/truck rearend setup is what you're leaning towards, final drive gearing needs to be selected based on drum diameter, since larger diameter drums call for higher gear ratios in the rearends... a small price to pay considering. There are spreadsheets and other files covering all this on winchdesign BTW -Paul PS. join the winchdesign group and comb the postings and files there as well as keeping up on new ones...http://groups.yahoo.com/group/winchdesign/*-that is if you can handle more episodes of the Derek/Bill show * The ratio of drum width to feed is 10:1 for unassisted level winding. So an 8-inch wide drum needs 80 inches. *The Gehrlein Model 62 distance is about 88 inches from axle to rollers. *The drum I had built is 8.5 inches wide. *A high ratio can only make it more effective. That said, the winch at Littlefield, TX, uses a simple level wind that is easy to maintain and works very well on their wide drum. *The wide drum advantage is the there is a small shift in the torque arm as the drum loads. Frank Whiteley The German DAeC winch recommendation calls for an 18:1 ratio between fairlead pulleys and the drum width. However, that's for steel cable. "Plastic Rope" seems to spread out nicely so even 8:1 seems to work. |
#148
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SAFE Winch Launching and automatic gearboxes
On Jul 22, 12:48*pm, tommytoyz wrote:
Bill, How much did the Gehrlein overhaul cost? Perhaps this could process can be replicated several times over. My guess is that once small scale winch launching grabs a foothold via Gehrlein winches and it becomes more popular and more pilots get winch certified, that demand will grow and we'll see the need for more productive multiple drum winches. Perhaps we can then use the Gehrleins as retrieve winches at that point. Launch costs can be brought down so low, as to stimulate soaring in this country. I myself am tired of paying $50 for one single aerotow - it's nuts. Nothing will stimulate soaring more than to bring the costs down and winch launching not only does that but makes soaring more challenging and fun too! I know, I'm preaching to the choir. So, choir, we need a cheap initial solution to get things moving - to demonstrate and get people certified - before we can realistically talk about expensive, albeit more productive, winches. Tom So far, it's probably in the $4000 - $5000 range but this particular winch was well worn out and, in it's original form, not really usable. Winch works now but refurbishing is still underway. 1. Replaced engine with a GM rebuilt long block for about $1400. New ignition, carburetor added another $600. 2. Rebuilt the '57 Chevy rear end with 3:55 gears for about $700 with new wheel bearings. (Better idea: put '57 Chevy parts on e-Bay and use proceeds to buy new winch.) 3. Sawed off old roller box and replaced it with a "Spectra friendly" pulley/guillotine assembly for about $1000. Drawings available. 6. A Bunch of other bits like electric radiator fans. |
#149
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SAFE Winch Launching and automatic gearboxes
On Jul 22, 10:30*am, Dave Martin wrote:
So what are you saying Bill? That old technology actually works and being brought up to date does the job people want? Well, not really. You could say a Model T "works" but you wouldn't want to take one on a California Freeway. They're good enough to get started but I really hope to see them quickly replaced with far, far better equipment. You have to put the word "works" in quotes since a refurbished Gerhlein winch only works as well as it did in the '50's - except for the Plasma Rope which is light years ahead of steel cable. There's a technology gulf of more than half a century between the technology in an old Gerhlein and state-of-the-art winches like the Hydrowinch. These old winches are highly dependent on skilled winch operators and benign operating conditions. They can still deliver some big surprises under non-optimum conditions. There are virtually no safeguards against operator error or really much protection for the winch operator. Even under optimum conditions, one launch is rarely like the one before. |
#150
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SAFE Winch Launching and automatic gearboxes
On Jul 21, 4:12*pm, tommytoyz wrote:
Perhaps the way to go is just buy a good used winch from a European club. What was the offered price again for that old Tost winch at Lasham? My German contacts recommend against buying an old Tost winch since the parts they are made from are no longer available. In many ways they share the same technology as the old Gerhleins. |
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