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On Jul 22, 12:30*am, Derek Copeland wrote:
At 22:01 21 July 2009, tommytoyz wrote:I see that their main business is making winches and that's why they charge what they charge. But it doesn't make sense to spend $90,000 on their cheaper system, not including transportation costs to the US, when the engine/transmission costs less than $10,000. I mean, $5,000 for a GUILLOTINE ASSEMBLY for over $5,000 on a double drum - come on. Perhaps the best way to go is buy the bare bones Kit for a "mere" $44,000 not counting transportation. Any way you slice it, with Skylaunch, it's not possible to be operational for less than $60,000, which would include a lot of sweat equity. I think it's a bit much. Tom On the other hand you are paying for expertise, development costs and a machine that is known to be safe, to work well and to be easy to drive. There is a lot more to a decent winch than just the engine and gearbox. How much would you expect to pay for a decent towplane? There are many homebuilt winches lying around rusting because they didn't work well or were just bloody dangerous. Any money spent on them was wasted. As Skylaunch import their engines from the US anyway, it would make sense to buy them locally rather than shipping them twice across the Atlantic. Derek Copeland It would make still more sense to just look at the "special parts" and build equivalents in the US. There's no "magic" in the Skylaunch that couldn't be replicated here at much lower cost - assuming you'd acutally want to do that. "You can take the transmission out of the road vehicle, but you can't take the road vehicle behavior out of the transmission." Actually, a different picture is emerging about these old US winches. Most of them seem to have been taken out of service when they simply wore out and because aero tow became universally available not because they didn't work. Then there's the fact that they were built to launch then current gliders which didn't require so much power. A recent Gerhlein refurbishment project ended with the overhaul or replacement of just about everything except the license plate. |
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So what are you saying Bill?
That old technology actually works and being brought up to date does the job people want? Dave At 15:39 22 July 2009, bildan wrote: On Jul 22, 12:30=A0am, Derek Copeland wrote: At 22:01 21 July 2009, tommytoyz wrote:I see that their main business is= making winches and that's why they charge what they charge. But it doesn't make sense to spend $90,000 on their cheaper system, not including transportation costs to the US, when the engine/transmission costs less than $10,000. I mean, $5,000 for a GUILLOTINE ASSEMBLY for over $5,000 on a double drum - come on. Perhaps the best way to go is buy the bare bones Kit for a "mere" $44,000 not counting transportation. Any way you slice it, with Skylaunch, it's not possible to be operational for less than $60,000, which would include a lot of sweat equity. I think it's a bit much. Tom On the other hand you are paying for expertise, development costs and a machine that is known to be safe, to work well and to be easy to drive. There is a lot more to a decent winch than just the engine and gearbox. How much would you expect to pay for a decent towplane? There are many homebuilt winches lying around rusting because they didn't work well or were just bloody dangerous. Any money spent on them was wasted. As Skylaunch import their engines from the US anyway, it would make sense to buy them locally rather than shipping them twice across the Atlantic. Derek Copeland It would make still more sense to just look at the "special parts" and build equivalents in the US. There's no "magic" in the Skylaunch that couldn't be replicated here at much lower cost - assuming you'd acutally want to do that. "You can take the transmission out of the road vehicle, but you can't take the road vehicle behavior out of the transmission." Actually, a different picture is emerging about these old US winches. Most of them seem to have been taken out of service when they simply wore out and because aero tow became universally available not because they didn't work. Then there's the fact that they were built to launch then current gliders which didn't require so much power. A recent Gerhlein refurbishment project ended with the overhaul or replacement of just about everything except the license plate. |
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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. |
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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 |
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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 Once you have the winch, budget $10,000-$20,000 for engine/ transmission, battery, wiring, new drum, feed assembly and guillotine improvement, tires, UHMWPE rope, chute/disk, rings, weak links, strop, paint, good communications devices and chocks. Frank Whiteley |
#6
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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. |
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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 ![]() |
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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 |
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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. |
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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. The hydrowinch feed is a single sheave approximately 8inches in diameter, perhaps an 1.25" wide with a tapering v-notch. Aluminum and powder coated. I suspect a common bearing type. Close enough tolerance in the fairlead to avoid problems. The original drum has been reinforced at the center, but has a u- shaped cross section. About 36" at inner core. See my other post about the drum I recently had built. Worked fine though the axle shaft align is slightly off leading to a slight tendancy to load the rope to one side. A bit of cutting and welding needed to correct this. Images in winchdesign Yahoo group. Frank Whiteley |
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