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#11
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Bob
I think Marcel answered your questions I can think of and know of instances where the winch driver should cut the cable instantly, moving or stationary. Should -- must -- need -- want -- ought to cut the cable are all subjective and cannot be answered fully in the space available. Ultimately I suppose on which side of the incident you are sitting, on the winch or in the air and the final outcome. I witnessed an incident where the pilot on a winch launch failed to take the correct action when travelling too fast, he released and accelerated flying under the cable which then wrapped itself round the glider. Removed the tail plane and embedded itself in the fin The glider did a neat 180 and then dived at about 45 degrees earthwards. The winch driver did not cut the cable. Just before the glider hit the ground, the winch cable pulled tight and stopped the glider in mid air. It 'landed' with greatly reduce forward speed and energy. It hit the ground almost flat. The glider was wrecked but the pilot lived. Talking to the winch driver afterward, he failed to cut the cable because events happened so fast, he froze. It was probably all over in less than 10 seconds. Whatever the incident, the winch driver MUST have the facility to cut the rope. Only hindsight will tell whether he should have or should not have cut the cable. The answer to the problem is training the brain on each end of the wire to treat the wire and the winch with utmost respect. Dave Martin |
#12
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As I am sure Dave Martin knows there was another accident in the U.K. where
the cable got round the glider's wing after the glider had released it. The winch driver operated the cutter while the glider was still drawing the cable out, which did not succeed in cutting the cable; the winch driver was left with nothing else he could do, then the cable hung up, tightened, and the pilot was killed. So here was a case where it was necessary to cut the cable when it was moving. W.J. (Bill) Dean (U.K.). Remove "ic" to reply. "Dave Martin" wrote in message ... Bob I think Marcel answered your questions I can think of and know of instances where the winch driver should cut the cable instantly, moving or stationary. Should -- must -- need -- want -- ought to cut the cable are all subjective and cannot be answered fully in the space available. Ultimately I suppose on which side of the incident you are sitting, on the winch or in the air and the final outcome. I witnessed an incident where the pilot on a winch launch failed to take the correct action when travelling too fast, he released and accelerated flying under the cable which then wrapped itself round the glider. Removed the tail plane and embedded itself in the fin The glider did a neat 180 and then dived at about 45 degrees earthwards. The winch driver did not cut the cable. Just before the glider hit the ground, the winch cable pulled tight and stopped the glider in mid air. It 'landed' with greatly reduce forward speed and energy. It hit the ground almost flat. The glider was wrecked but the pilot lived. Talking to the winch driver afterward, he failed to cut the cable because events happened so fast, he froze. It was probably all over in less than 10 seconds. Whatever the incident, the winch driver MUST have the facility to cut the rope. Only hindsight will tell whether he should have or should not have cut the cable. The answer to the problem is training the brain on each end of the wire to treat the wire and the winch with utmost respect. Dave Martin |
#13
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Hello Bill --
In an attempt to summarize the search for an effective synthetic rope guillotine then, I would say that we are expecting to develop an emergency line cutter at least as effective and safe as those we already employ against steel lines, stranded and solid, moving and stationary. Since the numerous winch builders and users on your side of the pond will by necessity be building and rigorously testing an ideal unit fairly soon, we'll be interested in learning of your solution(s) to the problem! I personally favor trying a "cigar cutter" powered by a compressed gas cylinder. The cutting blade could be veed to gather the line into the stationary blade and suitable finger guards can be added to prevent injuries. The actuating cylnder diameter can be made as large as necessary to multiply the bottle force enough to secure a successful cut. Also, at least two units could be installed to provide a backup. In the oilfield we use diaphragm operated rising stem valves that could be adapted for trials by developing a new valve "trim". A typical 6-inch diaphragm valve would have about 25 sq in of area. Powered by only a 100 psi cylinder, around 2500 lb of downward force would be available to the descending stem. That ought to cut something. A plus is that the valve body could have short pipe nipples screwed onto each end, rendering personal injuries a non-issue. These nipples could also be used to secure the unit the the winch by use of heavy duty pipe clamps. Finally,the higher the pressure, the larger the gas cylinder and the smaller the diaphragm, the faster the unit would operate. BJ "W.J. (Bill) Dean (U.K.)." wrote: As I am sure Dave Martin knows there was another accident in the U.K. where the cable got round the glider's wing after the glider had released it. The winch driver operated the cutter while the glider was still drawing the cable out, which did not succeed in cutting the cable; the winch driver was left with nothing else he could do, then the cable hung up, tightened, and the pilot was killed. So here was a case where it was necessary to cut the cable when it was moving. W.J. (Bill) Dean (U.K.). Remove "ic" to reply. "Dave Martin" wrote in message ... Bob I think Marcel answered your questions I can think of and know of instances where the winch driver should cut the cable instantly, moving or stationary. Should -- must -- need -- want -- ought to cut the cable are all subjective and cannot be answered fully in the space available. Ultimately I suppose on which side of the incident you are sitting, on the winch or in the air and the final outcome. I witnessed an incident where the pilot on a winch launch failed to take the correct action when travelling too fast, he released and accelerated flying under the cable which then wrapped itself round the glider. Removed the tail plane and embedded itself in the fin The glider did a neat 180 and then dived at about 45 degrees earthwards. The winch driver did not cut the cable. Just before the glider hit the ground, the winch cable pulled tight and stopped the glider in mid air. It 'landed' with greatly reduce forward speed and energy. It hit the ground almost flat. The glider was wrecked but the pilot lived. Talking to the winch driver afterward, he failed to cut the cable because events happened so fast, he froze. It was probably all over in less than 10 seconds. Whatever the incident, the winch driver MUST have the facility to cut the rope. Only hindsight will tell whether he should have or should not have cut the cable. The answer to the problem is training the brain on each end of the wire to treat the wire and the winch with utmost respect. Dave Martin |
#14
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Hi Bob
I do not think we have numerous winch builders on this side of the pond, possibly four in Europe. Before we get into expensive guillotines we need to prove the cable with the kit we have. Part of the cost effective equation would be installing new guillotines on existing winches. Possibly developing a graft on guillotine so the winch can use either steel or synthetic. I don't see a major technical problem with this just an expense that may prevent clubs from adopting the rope But first let us prove the cable. Dave PS I can report that I have had several generous offers of financial help. A few more and we could be looking at a realistic project. Dave In an attempt to summarize the search for an effective synthetic rope guillotine then, I would say that we are expecting to develop an emergency line cutter at least as effective and safe as those we already employ against steel lines, stranded and solid, moving and stationary. Since the numerous winch builders and users on your side of the pond will by necessity be building and rigorously testing an ideal unit fairly soon, we'll be interested in learning of your solution(s) to the problem! I personally favor trying a 'cigar cutter' powered by a compressed gas cylinder. The cutting blade could be veed to gather the line into the stationary blade and suitable finger guards can be added to prevent injuries. The actuating cylnder diameter can be made as large as necessary to multiply the bottle force enough to secure a successful cut. Also, at least two units could be installed to provide a backup. In the oilfield we use diaphragm operated rising stem valves that could be adapted for trials by developing a new valve 'trim'. A typical 6-inch diaphragm valve would have about 25 sq in of area. Powered by only a 100 psi cylinder, around 2500 lb of downward force would be available to the descending stem. That ought to cut something. A plus is that the valve body could have short pipe nipples screwed onto each end, rendering personal injuries a non-issue. These nipples could also be used to secure the unit the the winch by use of heavy duty pipe clamps. Finally,the higher the pressure, the larger the gas cylinder and the smaller the diaphragm, the faster the unit would operate. BJ |
#15
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Hello Dave-
This is an extreme statement, so I make it in jest, but I could build something out of balsa wood that would serve when someone asked if I have a guillotine, I could reply with some confidence, "Yes, I have a guillotine"! 8) BJ Dave Martin wrote: Hi Bob I do not think we have numerous winch builders on this side of the pond, possibly four in Europe. Before we get into expensive guillotines we need to prove the cable with the kit we have. Part of the cost effective equation would be installing new guillotines on existing winches. Possibly developing a graft on guillotine so the winch can use either steel or synthetic. I don't see a major technical problem with this just an expense that may prevent clubs from adopting the rope But first let us prove the cable. Dave PS I can report that I have had several generous offers of financial help. A few more and we could be looking at a realistic project. Dave In an attempt to summarize the search for an effective synthetic rope guillotine then, I would say that we are expecting to develop an emergency line cutter at least as effective and safe as those we already employ against steel lines, stranded and solid, moving and stationary. Since the numerous winch builders and users on your side of the pond will by necessity be building and rigorously testing an ideal unit fairly soon, we'll be interested in learning of your solution(s) to the problem! I personally favor trying a 'cigar cutter' powered by a compressed gas cylinder. The cutting blade could be veed to gather the line into the stationary blade and suitable finger guards can be added to prevent injuries. The actuating cylnder diameter can be made as large as necessary to multiply the bottle force enough to secure a successful cut. Also, at least two units could be installed to provide a backup. In the oilfield we use diaphragm operated rising stem valves that could be adapted for trials by developing a new valve 'trim'. A typical 6-inch diaphragm valve would have about 25 sq in of area. Powered by only a 100 psi cylinder, around 2500 lb of downward force would be available to the descending stem. That ought to cut something. A plus is that the valve body could have short pipe nipples screwed onto each end, rendering personal injuries a non-issue. These nipples could also be used to secure the unit the the winch by use of heavy duty pipe clamps. Finally,the higher the pressure, the larger the gas cylinder and the smaller the diaphragm, the faster the unit would operate. BJ |
#16
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Has anyone approached the rope suppliers for some developement funding
I would think that to enlarge their market that some funds could be allocatted possibly from their advertising budget since they don't have to advertise to gain clients. gary "Bob Johnson" wrote in message ... Hello Bill -- In an attempt to summarize the search for an effective synthetic rope guillotine then, I would say that we are expecting to develop an emergency line cutter at least as effective and safe as those we already employ against steel lines, stranded and solid, moving and stationary. Since the numerous winch builders and users on your side of the pond will by necessity be building and rigorously testing an ideal unit fairly soon, we'll be interested in learning of your solution(s) to the problem! I personally favor trying a "cigar cutter" powered by a compressed gas cylinder. The cutting blade could be veed to gather the line into the stationary blade and suitable finger guards can be added to prevent injuries. The actuating cylnder diameter can be made as large as necessary to multiply the bottle force enough to secure a successful cut. Also, at least two units could be installed to provide a backup. In the oilfield we use diaphragm operated rising stem valves that could be adapted for trials by developing a new valve "trim". A typical 6-inch diaphragm valve would have about 25 sq in of area. Powered by only a 100 psi cylinder, around 2500 lb of downward force would be available to the descending stem. That ought to cut something. A plus is that the valve body could have short pipe nipples screwed onto each end, rendering personal injuries a non-issue. These nipples could also be used to secure the unit the the winch by use of heavy duty pipe clamps. Finally,the higher the pressure, the larger the gas cylinder and the smaller the diaphragm, the faster the unit would operate. BJ "W.J. (Bill) Dean (U.K.)." wrote: As I am sure Dave Martin knows there was another accident in the U.K. where the cable got round the glider's wing after the glider had released it. The winch driver operated the cutter while the glider was still drawing the cable out, which did not succeed in cutting the cable; the winch driver was left with nothing else he could do, then the cable hung up, tightened, and the pilot was killed. So here was a case where it was necessary to cut the cable when it was moving. W.J. (Bill) Dean (U.K.). Remove "ic" to reply. "Dave Martin" wrote in message ... Bob I think Marcel answered your questions I can think of and know of instances where the winch driver should cut the cable instantly, moving or stationary. Should -- must -- need -- want -- ought to cut the cable are all subjective and cannot be answered fully in the space available. Ultimately I suppose on which side of the incident you are sitting, on the winch or in the air and the final outcome. I witnessed an incident where the pilot on a winch launch failed to take the correct action when travelling too fast, he released and accelerated flying under the cable which then wrapped itself round the glider. Removed the tail plane and embedded itself in the fin The glider did a neat 180 and then dived at about 45 degrees earthwards. The winch driver did not cut the cable. Just before the glider hit the ground, the winch cable pulled tight and stopped the glider in mid air. It 'landed' with greatly reduce forward speed and energy. It hit the ground almost flat. The glider was wrecked but the pilot lived. Talking to the winch driver afterward, he failed to cut the cable because events happened so fast, he froze. It was probably all over in less than 10 seconds. Whatever the incident, the winch driver MUST have the facility to cut the rope. Only hindsight will tell whether he should have or should not have cut the cable. The answer to the problem is training the brain on each end of the wire to treat the wire and the winch with utmost respect. Dave Martin |
#17
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At 18:48 04 November 2003, Goneill wrote:
Has anyone approached the rope suppliers for some developement funding I would think that to enlarge their market that some funds could beallocatted possibly from their advertising budget since they don't have to advertise to gain clients. gary I have approached the UK importer and he looking into this prospect and other avenues are being tried Dave |
#18
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the gliding school Oerlinghausen in Germany
is using the plasma cable as well. I was told, that a small modifiaction of the capping system did the trick, but I have no details. Chris "Robert Makin" wrote in message ... There is considerable interest in the UK in using plasma/dyneema rope for winch launching. However, the main obstacle appears to be finding an efficient method of cutting the rope in event of an emergency. Has anyone ot there found the definitive method??? |
#19
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I translated the important part off a Winch Homepage from German. in
one of the other threads! They modify the Guilutine so it comes down on a brass anvil,over which the rope is running. The cutting device, probably something like a big knife,more like chopping than a shearing action. Dieter "CH" wrote in message ... the gliding school Oerlinghausen in Germany is using the plasma cable as well. I was told, that a small modifiaction of the capping system did the trick, but I have no details. Chris "Robert Makin" wrote in message ... There is considerable interest in the UK in using plasma/dyneema rope for winch launching. However, the main obstacle appears to be finding an efficient method of cutting the rope in event of an emergency. Has anyone ot there found the definitive method??? |
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