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#1
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"Mark James Boyd" wrote in message news:405aa3e8$1@darkstar... I'd love to see a winch design that uses a 100hp or less engine, can be easily bolted on the back of an old pickup, and has engine and parts that are low maintenance and (especially engine) easy to acquire (either locally or via shipping). Alternately, how about a "spare tire" that is really a winch drum. a stable sturdy "jack" and some way to route the cable to ensure it winds up nice. Might not work (thoughts of side loads tipping my car over come to mind!), but it sure is fun to play with the thuoght! -- ------------+ Mark Boyd Avenal, California, USA Mark, unfortunately, the physics of a winch launch says that it takes about 1 kWh or 3,600,000 Joules to launch a glider. The peak power demand places yet another constraint on the minimum HP that must be available. Those numbers point to a 400 to 500 HP engine to be able to provide launch service to any glider in the existing fleet. Although the initial cost of a well engineered winch is high (nearly as much as a tow plane) the long term costs are only a few percent as much a tug. The good news is that the total energy consumed for one launch (About 1 liter of diesel fuel equivalent) is tiny compared to any other launch method except bungee launch. (Excluding, of course, the beer you have to provide the bungee crew.) A glider winch is a highly specialized piece of machinery that needs the kind of engineering Ulrich is asking for. Please avoid the temptation to cobble some junk together to make a barely workable winch. That sort of thing has given winch launch a bad name in the USA. A well run winch operation is very attractive to newcomers to the sport. It shows a lot of ground activity that is visible to the onlookers and the rides are a real thrill. Lets get winching! Bill Daniels |
#3
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"mat Redsell" wrote in message ...
I really think this idea has merit.... but should we also consider lowering the wing loading so that the horsepower requirements are much less? I also think that the future of soaring is rather bleak without winch alternatives. Mat, I don't think that the road-block for whole winch idea is horse-power. Horse-Power is available in abundance at a reasonable cost - see Bill Daniels' write-up on this subject. Even with a high HP winch, older, smaller and lighter gliders can be launched. It is only when you have a fully watered open ship or heavy double seat trainer on the other end of the cable when you need the extra uhmpf! I think the biggest problem to overcome is the mind-set that the winch has to be built (cobbled together) in one weekend from parts supplied exclusively from the local junk-yard. Lets apply some sound engineering, craftsmenship and parts, that are commercially available for years to come. Ulrih Neumann |
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#5
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Ulrich,
See if you can find a contact at "The Soaring Centre", Husbands Bosworth in UK. Some years ago they built their own 4-drum winch. I saw it a few years ago, and it was a most impressive machine. Unfortunately I don't have any contact info for them, but they do have a web site at: http://www.thesoaringcentre.co.uk/index.htm Cheers, John G. (Australia) "Ulrich Neumann" wrote in message om... "mat Redsell" wrote in message ... I really think this idea has merit.... but should we also consider lowering the wing loading so that the horsepower requirements are much less? I also think that the future of soaring is rather bleak without winch alternatives. Mat, I don't think that the road-block for whole winch idea is horse-power. Horse-Power is available in abundance at a reasonable cost - see Bill Daniels' write-up on this subject. Even with a high HP winch, older, smaller and lighter gliders can be launched. It is only when you have a fully watered open ship or heavy double seat trainer on the other end of the cable when you need the extra uhmpf! I think the biggest problem to overcome is the mind-set that the winch has to be built (cobbled together) in one weekend from parts supplied exclusively from the local junk-yard. Lets apply some sound engineering, craftsmenship and parts, that are commercially available for years to come. Ulrih Neumann |
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In article , "John Giddy"
writes: See if you can find a contact at "The Soaring Centre", Husbands Bosworth in UK. Some years ago they built their own 4-drum winch. I saw it a few years ago, and it was a most impressive machine. True, we do have a very good winch. It is four drum and was designed by engineers and largely built by a retired member and his son who knew what they were doing, but to a very high standard, and is not dissimilar to the van Gelder (which has 6 drums I believe) . Must be about 10 or 12 years old now and has given excellent service with the occasional overhaul. It can launch anything we have including Duo Discus, Janus, Puchacz and other two seaters with no problem but is on full throtle with no wind. Unfortunately the member (and his son) who built it are no longer available, (son now flies Jumbo jets and father is not interested in another project of this type). However, we would willingly show you round and our Winch Master will no doubt tell you all about our "learning curve". If you are new to winching I strongly recommend buying a professionally made two drum winch, Supercat for example, as I guarantee that, without a clear blueprint you will never get the engineering right first time and would waste many frustrating hours, lots of cash, and end up with an unsatisfactory product. Barney The Soaring Centre UK |
#7
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"BAToulson" wrote in message ... In article , "John Giddy" writes: See if you can find a contact at "The Soaring Centre", Husbands Bosworth in UK. Some years ago they built their own 4-drum winch. I saw it a few years ago, and it was a most impressive machine. True, we do have a very good winch. It is four drum and was designed by engineers and largely built by a retired member and his son who knew what they were doing, but to a very high standard, and is not dissimilar to the van Gelder (which has 6 drums I believe) . Must be about 10 or 12 years old now and has given excellent service with the occasional overhaul. It can launch anything we have including Duo Discus, Janus, Puchacz and other two seaters with no problem but is on full throtle with no wind. Unfortunately the member (and his son) who built it are no longer available, (son now flies Jumbo jets and father is not interested in another project of this type). However, we would willingly show you round and our Winch Master will no doubt tell you all about our "learning curve". If you are new to winching I strongly recommend buying a professionally made two drum winch, Supercat for example, as I guarantee that, without a clear blueprint you will never get the engineering right first time and would waste many frustrating hours, lots of cash, and end up with an unsatisfactory product. Barney The Soaring Centre UK Post some detailed digital images to the winch design group at yahoogroups.com please. TIA, Frank Whiteley |
#8
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Not exactly what you asked for, but take a look at
http://www.skylaunch.de/album/index.html It's fun and it may give you some ideas. Stefan |
#9
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See also: http://www.proximedia.com/local/neth...el/various.htm
Diederik BTW: I have winched twin astirs, fully loaded, k-8's, T-21 tutor and prefects with a 350 hp winch. No problem, it's just how you adjust the throtle Stefan wrote in message ... Not exactly what you asked for, but take a look at http://www.skylaunch.de/album/index.html It's fun and it may give you some ideas. Stefan |
#10
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Bill,
I think you need to revisit your numbers. Here at Nympsfield (UK) we have a Supacat winch with a 250 horse Diesel that easily provides enough power for the biggest gliders on site (DG505, DuoDT, Nimbus3DT) (And pretty scary in a Libelle if the winch driver is *over enthusiastic*) The previous engine was 180 HP, this was a bit marginal for the Heavy Glass, but more than enough for any single seat (We have a 1000m field & regularly get 1500', even nil wind) :-) KN At 15:36 19 March 2004, Bill Daniels wrote: Mark, unfortunately, the physics of a winch launch says that it takes about 1 kWh or 3,600,000 Joules to launch a glider. The peak power demand places yet another constraint on the minimum HP that must be available. Those numbers point to a 400 to 500 HP engine to be able to provide launch service to any glider in the existing fleet. |
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