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#111
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A related remembrance...
Years ago I attended a mid-summer's eve cookout at Ridge Soaring in central PA. For entertainment we were armchairing the end o'day training flights. A glider released just after take-off, landing at the far end of the field. The tow plane landed, then taxied down to launch the glider in the opposite direction. As the tug passed us, 2-33 in tow, KS asked what was going on. I explained that a series of rope breaks were practiced as a student got close to solo. They had just completed a straight ahead release and recovery and would now practice a 180 for return to the runway. As the tow plane and glider reached 20 feet above the ground, still short of the runway boundary, Karl said, "Now! It would be hairy, but you could do it." Karl and a handfull of other pilots probably could. The rest of us wait until we have enough altitude to more than measure the sins we're likely to commit as the emergency unfolds -- 200 feet being an appropriate indulgence. For those who need to know to the inch, don't forget to include 35% of your wingspan, lest you bury a tip. And don't forget that anytime the controls are not neutral, your sink rate goes well below the arc of the polar. So far, of the math I've seen, success would only be achieved for gliders of zero span requiring no control input (and resulting drag) to initiate a bank or roll out of it. |
#112
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"Chris OCallaghan" wrote in message om... A related remembrance... Years ago I attended a mid-summer's eve cookout at Ridge Soaring in central PA. For entertainment we were armchairing the end o'day training flights. A glider released just after take-off, landing at the far end of the field. The tow plane landed, then taxied down to launch the glider in the opposite direction. As the tug passed us, 2-33 in tow, KS asked what was going on. I explained that a series of rope breaks were practiced as a student got close to solo. They had just completed a straight ahead release and recovery and would now practice a 180 for return to the runway. As the tow plane and glider reached 20 feet above the ground, still short of the runway boundary, Karl said, "Now! It would be hairy, but you could do it." Karl and a handfull of other pilots probably could. The rest of us wait until we have enough altitude to more than measure the sins we're likely to commit as the emergency unfolds -- 200 feet being an appropriate indulgence. For those who need to know to the inch, don't forget to include 35% of your wingspan, lest you bury a tip. And don't forget that anytime the controls are not neutral, your sink rate goes well below the arc of the polar. So far, of the math I've seen, success would only be achieved for gliders of zero span requiring no control input (and resulting drag) to initiate a bank or roll out of it. Not to belabor the obvious, but a 180 return to the runway from a 200 foot airtow rope break is not always possible. We tend to talk as if it were true but if believe it, we may be setting up a disaster. With a heavy glider, weak tug, high density altitude and unfavorable wind (and maybe a thick headed tug pilot) you may need as much as 1000 feet to be in a position for a safe return to the airfield. There have been many occasions when my left hand hovered near the release in preparation for a simulated rope break. But, looking back over my shoulder at the airfield, I thought, "I don't theeenk so" and let the student continue. Over the last year a young friend of mine (A CFI-G) suffered two low altitude rope breaks (weak link failures) and each incident resulted in an off-airfield landing. (To his credit - no damage) Bill Daniels |
#113
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Frank Whiteley wrote[snip]
There once was a non-BGA soaring site/club in East Anglia in the UK. The operator was named Fred, but the surname escapes me and I believe he passed away in the 1980's. By all accounts he operated a steam winch [snip] Freddie Wiseman was the man, and the winch was not steam powered, but diesel. It was remarkable in that it was a converted combine harvester. I have a photo of it somewhere. I saw it working. It was rather low powered, and operated via huge canvas belt drives which were "interesting". Not technology I would suggest repeating elsewhere. The site was Ridgewell (ex 381st BG base 1943-45), where I now fly from - see http://www.essexgliding.org/index.htm The winch was fairly lethal, potentially - I knew one of the drivers who had to contend with a broken cable still under power thrashing around in the cab. After Freddie's death in 1984 a few people revived the club and continued to use the combine winch until 1988. When my club bought the site the winch was still intact and was brought back, but we decided not to use it and instead bought other winches. The only time I know of using it in our time was as a towing vehicle, when we moved two huts and the tractors got bogged down (don't ask - it's a long story). It did the rescue but burnt out its clutch in the process. It was eventually scrapped about three years ago. Relevance to the subject line - it was dangerous to the operator, but never hurt a pilot - instead gave lots of practice, as is only right, in "premature terminations of launch" and "too low in circuit". Chris N. |
#114
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#115
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"Jack" wrote in message ... in article et, Bill Daniels at wrote on 2003/10/31 11:39: ...a 180 return to the runway from a 200 foot airtow rope break is not always possible. ...you may need as much as 1000 feet to be in a position for a safe return to the airfield. ...two low altitude rope breaks (weak link failures) and...resulted in...off-airfield landing[s]. More specifics please for those off-airport landings. Otherwise your "1000 feet" may be taken by some as a bit of an exageration. Jack In my friends case, the first break came shortly after crossing the field boundary at about 50 feet. This was a case of insufficient climb angle to reach 200 feet while still in range of the runway. The other, as I understand it, was at about 300 feet but still out of gliding range of the airport. My comment about 1000 feet referred to a situation that happened to me because the tug pilot turned downwind at 100 feet AGL with a heavy glider and strayed still further downwind as the air tow ground on despite urgent radio calls. It was only at 1000 feet AGL that I felt that I could release and get back. (and get another tug pilot) This has happened to me too many times to recall all of them. Understand, I fly in an area where density altitude at takeoff can exceed 10,000 feet. It takes a strong tug to keep a heavy two seater constantly in range of the runway. My point with the original post is that there is no guarantee that the magic 200 feet AGL will always get you back. Bill Daniels |
#116
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#117
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Indeed, aerotow can sometimes be interesting! Some years ago I was flying in
a local club competition and found myself behind an underpowered Rallye, piloted by a man with a recently diagnosed heart condition who therefore needed a safety pilot with him. (Yes, I know the correct response is to refuse the tow, but competitions soften the safety cells in the brain, even local club competitions). We climbed (very slowly) to 400ft and then stayed there while we flew in a straight line at least 3 miles from the airfield. It's the only time I've been field spotting on tow for such a long time. Not suprisingly, I failed to soar once we reached the release height of 2,000 ft (partly because I only had time for once centreing turn if I was to remain within gliding range of the field). My relight was a winch launch! "Bill Daniels" wrote in message ink.net... "Chris OCallaghan" wrote in message om... A related remembrance... Years ago I attended a mid-summer's eve cookout at Ridge Soaring in central PA. For entertainment we were armchairing the end o'day training flights. A glider released just after take-off, landing at the far end of the field. The tow plane landed, then taxied down to launch the glider in the opposite direction. As the tug passed us, 2-33 in tow, KS asked what was going on. I explained that a series of rope breaks were practiced as a student got close to solo. They had just completed a straight ahead release and recovery and would now practice a 180 for return to the runway. As the tow plane and glider reached 20 feet above the ground, still short of the runway boundary, Karl said, "Now! It would be hairy, but you could do it." Karl and a handfull of other pilots probably could. The rest of us wait until we have enough altitude to more than measure the sins we're likely to commit as the emergency unfolds -- 200 feet being an appropriate indulgence. For those who need to know to the inch, don't forget to include 35% of your wingspan, lest you bury a tip. And don't forget that anytime the controls are not neutral, your sink rate goes well below the arc of the polar. So far, of the math I've seen, success would only be achieved for gliders of zero span requiring no control input (and resulting drag) to initiate a bank or roll out of it. Not to belabor the obvious, but a 180 return to the runway from a 200 foot airtow rope break is not always possible. We tend to talk as if it were true but if believe it, we may be setting up a disaster. With a heavy glider, weak tug, high density altitude and unfavorable wind (and maybe a thick headed tug pilot) you may need as much as 1000 feet to be in a position for a safe return to the airfield. There have been many occasions when my left hand hovered near the release in preparation for a simulated rope break. But, looking back over my shoulder at the airfield, I thought, "I don't theeenk so" and let the student continue. Over the last year a young friend of mine (A CFI-G) suffered two low altitude rope breaks (weak link failures) and each incident resulted in an off-airfield landing. (To his credit - no damage) Bill Daniels |
#118
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Chris Reed wrote:
We climbed (very slowly) to 400ft and then stayed there while we flew in a straight line at least 3 miles from the airfield. It's the only time I've been field spotting on tow for such a long time. Not suprisingly, I failed to soar once we reached the release height of 2,000 ft Was it not possible for you to use the in-air signals to steer the tow pilot back toward the field? |
#119
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Should we assume that these two rope breaks were during aero tow?
The next obvious question is how strong were the weak links and why did they break. The fact that this individual had two weak links break at a low enough altitude that it resulted in his landing off field, does make us wonder what the complete story is. Was he solo in a single place glider? Or was it a result of letting a student get too far out of position? Inquiring minds would like to know. M Eiler More specifics please for those off-airport landings. Otherwise your "1000 feet" may be taken by some as a bit of an exageration. Jack In my friends case, the first break came shortly after crossing the field boundary at about 50 feet. This was a case of insufficient climb angle to reach 200 feet while still in range of the runway. The other, as I understand it, was at about 300 feet but still out of gliding range of the airport. My comment about 1000 feet referred to a situation that happened to me because the tug pilot turned downwind at 100 feet AGL with a heavy glider and strayed still further downwind as the air tow ground on despite urgent radio calls. It was only at 1000 feet AGL that I felt that I could release and get back. (and get another tug pilot) This has happened to me too many times to recall all of them. Understand, I fly in an area where density altitude at takeoff can exceed 10,000 feet. It takes a strong tug to keep a heavy two seater constantly in range of the runway. My point with the original post is that there is no guarantee that the magic 200 feet AGL will always get you back. Bill Daniels |
#120
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Those interested in wire launch safety may like to read an article by
John Hoskins, BGA Accident Investigator, which has just been published. See http://www.gliding.co.uk/bgainfo/saf...s/winching.pdf or http://www.glidingmagazine.com/ListF...Dtl.asp?id=370 . There have been many accidents of the types described, insufficient energy to avoid a heavy landing after a launch failure, and a spin entry after stalling during the first part of the launch. W.J. (Bill) Dean (U.K.). Remove "ic" to reply. "Gary Boggs" wrote in message ... Someone must have already compared the safety of these tow launch methods. What do the statistics show is the safer method of launch? Aero tow seems to involve more inherent dangers to me. For one thing, there is just more time for things to go wrong. What could be more dangerous than to tie two airplanes together and try to fly? Gary Boggs |
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