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#11
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Excellent post Ed....thanks for sharing it with us. I hope that you are
doing well. I remember Chip showing us his system years ago when flying at Mid Atlantic Soaring. My only concern is the same that was posted back when this all was discussed in 1998....that is if the belts will withstand the loads placed upon them at angles that they were not designed for when using the system described by Chip. Does anyone have any further info about this? You out there Chip? I know that he was concerned re the liability issue of non-approved applications in the past so may not be willing to discuss this publicly. I have a crotch strap installed by myself in my experimental certificated glider (LS-8) but honestly only use it when on a fast final glide to keep my head from being bruised i.e. most of the flight it is not connected for relief reasons. It obviously wouldn't be much help laying there in the seat just prior to impacting something. Casey Lenox KC Phoenix |
#12
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ED
Glad you're doing well. I am curious--did the crotch strap attach point fail, or was it intact after the crash? If it did fail, at what estimated load did that occur? Pehaps it does not have to hold the entire load to be effective--your thoughts? Thanks Hartley Falbaum "Ed Byars" wrote in message hlink.net... I sent the following to our magazine nine months ago and didn't receive an acknowledgement or receipt. I guess it was not suitable for them so I thought I would share it with ras to maybe provoke some safety discussion. efb10-11-03-rev.6-5-04 You may be interested in my latest crotch strap experience. I'm still analyzing my June 2003 accident and the cause. More later on this. The role of the crotch strap is significant and worthy of mention. The last half dozen gliders I've had I added a crotch strap (usually available from Wings & Wheels), which easily clicks into the bottom, front or 5th slot of the standard Gadringer belt hardware. I secure the other end, which terminates with the belt into a triangular link, with a quarter inch hole that I bolt to the seat pan with a large "wood" washer behind the seat pan. My gliders are Experimental category so this is legal. I always heard that the main purpose of a crotch strap was to keep the lap belt across the upper thighs and prevent it sliding up to the stomach area. I have since learned better. It of course depends on the direction of the accident loads and the direction of the inertia of the body as to how all restraint straps come into play. Many glider accidents involve "dropping in" vertically wherein the tailbone (in the L-1, L-2 area) or higher are damaged so the belts don't help much. You seldom see accidents with lap belt overload, but it happens. I have a sad memory of helping remove a dead friend from an inverted Ventus cockpit where the lap belts on both sides had pulled lose from the seat pan. Fortunately rare but it happens. In my "incident" the nose of the glider hit hard ground at about a 60 plus degree angle. The "load" was about along the longitudinal axis of the glider. Since in our modern gliders (ASW-28 in my case) we recline (sit supine), the inertia of my body was toward the nose with only the crotch strap to resist. Actually Waibel designed the seat pan to take some of this forward load against the bottom of the thighs. In this seating the knees are bent more upward. The nose of the glider (along with my feet) was crushed in a calculated energy-absorbing manner. Thank you Gerhardt Waibel! I think his design and the crotch strap saved my knees. I was conscious and lucid until the helicopter dropped me off at the Medical College of Georgia Trauma Center. After that I really was not with it for a couple of weeks, but after that time I suddenly noticed that my groin area was still quite swollen. I realized that my crotch area had sustained a significant load and that all things considered had kept my body from moving more forward and no doubt helped minimize the leg/knee damage. I had no shoulder strap or lap belt marks or soreness. Since my guess is that a significant number of glider accidents impose loads and body reactions similar to mine, I recommend a crotch strap. Trying to distribute the load to the pelvic area by wearing an athletic "cup" may be good for some flights, but for some flights there are other disadvantages. Many contest pilots regularly wear a male external catheter and I don't think both would work. With just the crotch strap I always had to be careful that the strap was adjusted somewhat to the right, was not too tight, and did not interfere with the flow from the catheter that was to the left. I suggest reading Chip Bearden's posting which appeared in the rec.aviation.soaring newsgroup on Nov.20 1998 which outlines a more complex but better seat belt design. I hope this discussion will create more thought about glider accident safety. Ed Byars |
#13
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Alan Silver is very much still in business. See http://www.pia.com/silver/
-Bob Korves LAK-17a "5K DuoDiscus "5H" "Dusty" wrote in message m... Dale Thompson and I had an inverted V crotch strap in our 1-35. It served to keep the lap belt in position. More important was the assurance that the legs and hips would probably take the stress instead of other more "important" parts that could not be so easily repaired. Fortunately, we never had a test of its effectiveness. The design is very simple and easily made. Our was made by Alan Silver, in the San Francisco bay area, who repacked our chute. I do not think he is still in business. |
#14
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#15
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Tony Segal published a later article, which concluded six point
harnesses were superior to five point harnesses. I'll bet they are but does this not provide two more straps to un-fasten when the need for a quick egress arises? Or am I missing something? Robert Mudd |
#16
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It is possible to make a 6 point harness that simply falls away when
released. Some were trialled in Europe and the UK I believe . The plusses for a six point harness outweighed the negatives by a long way! I was trying to get hold of one but they appear to not have been able to get them certified. It is very difficult to innovate in the aviation industry without spending vast amounts of money and I think this vital innovation may have fallen foul of this. Perhaps DG offers this as an option? They seem to be the only real innovaters left on the soaring scene. Ian "Robertmudd1u" wrote in message ... Tony Segal published a later article, which concluded six point harnesses were superior to five point harnesses. I'll bet they are but does this not provide two more straps to un-fasten when the need for a quick egress arises? Or am I missing something? Robert Mudd |
#17
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Alan Silver
http://www.pia.com/silver/ We only send our parachutes to him. He is still repacking and making belts. This thread is making me wonder about if it was a good idea to get rid of that crotch strap. Garret |
#18
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Perhaps DG offers this as an option? They seem to be the only real
innovaters left on the soaring scene. Ian Perhaps, but Herr Weber has always been one of the most vocal in skeaking out, saying that 5th. belt/crotch straps are not needed. Robert Mudd |
#19
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Hi Hartley,
The crotch strap remained intact after doing it's job. I'm just lucky that no serious permanent damage was done to my sensitive genitals. I like the ideas presented relative to a six point arrangement. This sure sounds safer, but any sensible arrangement would be virtually impossible to get by the LBA/FAA. It's a shame that it's not likely that any competent person or group would/will develop and offer for sale such a glider system. Our legal system just would not allow it. Maybe such a system designed for another more numerous vehicle, auto probably, might be available for Experimental licensed gliders. From an overall safety standpoint it may be just as important to assure that any belting system is quickly free of the body with one quick push or twist. We must not forget that provision for a quick cockpit egress may be just as important. I'm pleased that this thread seems to have made a few of us review our restraint system and think about possible improvement. Ed Byars "HL Falbaum" wrote in message newsuPwc.19014$%F2.12354@attbi_s04... ED Glad you're doing well. I am curious--did the crotch strap attach point fail, or was it intact after the crash? If it did fail, at what estimated load did that occur? Pehaps it does not have to hold the entire load to be effective--your thoughts? Thanks Hartley Falbaum "Ed Byars" wrote in message hlink.net... I sent the following to our magazine nine months ago and didn't receive an acknowledgement or receipt. I guess it was not suitable for them so I thought I would share it with ras to maybe provoke some safety discussion. efb10-11-03-rev.6-5-04 You may be interested in my latest crotch strap experience. I'm still analyzing my June 2003 accident and the cause. More later on this. The role of the crotch strap is significant and worthy of mention. The last half dozen gliders I've had I added a crotch strap (usually available from Wings & Wheels), which easily clicks into the bottom, front or 5th slot of the standard Gadringer belt hardware. I secure the other end, which terminates with the belt into a triangular link, with a quarter inch hole that I bolt to the seat pan with a large "wood" washer behind the seat pan. My gliders are Experimental category so this is legal. I always heard that the main purpose of a crotch strap was to keep the lap belt across the upper thighs and prevent it sliding up to the stomach area. I have since learned better. It of course depends on the direction of the accident loads and the direction of the inertia of the body as to how all restraint straps come into play. Many glider accidents involve "dropping in" vertically wherein the tailbone (in the L-1, L-2 area) or higher are damaged so the belts don't help much. You seldom see accidents with lap belt overload, but it happens. I have a sad memory of helping remove a dead friend from an inverted Ventus cockpit where the lap belts on both sides had pulled lose from the seat pan. Fortunately rare but it happens. In my "incident" the nose of the glider hit hard ground at about a 60 plus degree angle. The "load" was about along the longitudinal axis of the glider. Since in our modern gliders (ASW-28 in my case) we recline (sit supine), the inertia of my body was toward the nose with only the crotch strap to resist. Actually Waibel designed the seat pan to take some of this forward load against the bottom of the thighs. In this seating the knees are bent more upward. The nose of the glider (along with my feet) was crushed in a calculated energy-absorbing manner. Thank you Gerhardt Waibel! I think his design and the crotch strap saved my knees. I was conscious and lucid until the helicopter dropped me off at the Medical College of Georgia Trauma Center. After that I really was not with it for a couple of weeks, but after that time I suddenly noticed that my groin area was still quite swollen. I realized that my crotch area had sustained a significant load and that all things considered had kept my body from moving more forward and no doubt helped minimize the leg/knee damage. I had no shoulder strap or lap belt marks or soreness. Since my guess is that a significant number of glider accidents impose loads and body reactions similar to mine, I recommend a crotch strap. Trying to distribute the load to the pelvic area by wearing an athletic "cup" may be good for some flights, but for some flights there are other disadvantages. Many contest pilots regularly wear a male external catheter and I don't think both would work. With just the crotch strap I always had to be careful that the strap was adjusted somewhat to the right, was not too tight, and did not interfere with the flow from the catheter that was to the left. I suggest reading Chip Bearden's posting which appeared in the rec.aviation.soaring newsgroup on Nov.20 1998 which outlines a more complex but better seat belt design. I hope this discussion will create more thought about glider accident safety. Ed Byars |
#20
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"Ed Byars" wrote in message Hi Hartley, The crotch strap remained intact after doing it's job. I'm just lucky that no serious permanent damage was done to my sensitive genitals. I like the ideas presented relative to a six point arrangement. This sure sounds safer, but any sensible arrangement would be virtually impossible to get by the LBA/FAA. SNIPPED Ed. Installing the belts in a sailplane is an exceptionally simple procedure. If experimental, just do it. If certified, file a 337 and get the field approval for the airplane you stick it in. Its quite simple to do and I haven't met a MIDO guy that didn't stamp it off immediately and wonder why they weren't there to begin with. Scott. |
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