peek 20 #1 November 27, 2006 A while back in this thread: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=1073912 I spoke of lightly loaded high performance canopies having stability issues. Yesterday I saw someone flying her (original) Sabre loaded at maybe 0.8 and at about 300 feet her end cell rolled under and snapped back out in about a 1 second period. Since there were no "obstacles" to create turbulence at 300 feet my guess is that the heat rising from the pavement (which was slightly upwind of the column of air in which she was flying) caused this turbulence. (It was very warm in the midwest this weekend.) So again, please use caution with lightly loaded high performance canopies, and brief the less experienced jumpers using this gear on the possibilities of this happening. (And please believe that this can happen on many models of high performance canopies.) About all else, teach them to not be landing downwind of obstacles, where we are sure there is turbulence. (We should be teaching them this anyway, but I still see experienced jumpers landing where they should not be.) Quote Share this post Link to post Share on other sites
ChrisL 2 #2 November 27, 2006 You are classifying an original (square) Sabre as high performance? Would you then say that any ZP 9 cell is high performance?__ My mighty steed Quote Share this post Link to post Share on other sites
phoenixlpr 0 #3 November 27, 2006 You may classify any canopy loaded over 1.0 as high performance. Quote Share this post Link to post Share on other sites
niu 0 #4 November 27, 2006 My 135 did that once in light turbulence,but it was not really lightly loaded.Just out of trim,I think,since it opened pretty badly during my last season. Even got to chop it once. Quote Share this post Link to post Share on other sites peek 20 #5 November 27, 2006 QuoteYou are classifying an original (square) Sabre as high performance? Would you then say that any ZP 9 cell is high performance? Perhaps, but I am not familiar with all 9 cell ZP canopies. This may sound confusing to those who have started skydiving since 9 cell ZP canopies became common, because even higher performance canopies have been developed since, but yes, the original Sabre is high performance. The Sabre was one of the first canopy designs to be trimmed flatter than the previous generation of canopies in order to make its performance higher, (and the zero porosity fabric made it stay that way for most of its life.) Much of a canopy's suceptability to collapse due to turbulence has to do with how pressurized the cells are, so wingloading, trim angle, (and whether the canopy has airlocks) are some major factors in this. Perhaps a better way of making this warning would be to say that nearly everyone with low wing loading is at danger now that most canopies are trimmed flatter (than the previous generation of canopies) now. To diverge from the topic a bit, some of the reason that people are still hurting themselves under canopy is that they may not consider an older design like the Sabre to be "high performance" and think they are OK with one, but the Sabre is high enough performance to bite you if you are not careful. "High performance" is on a sliding scale now, with the rapid advances in canopy design in the last decade. Back to the original topic: Be careful and get educated. Quote Share this post Link to post Share on other sites drudchen 0 #6 November 27, 2006 QuoteYou may classify any canopy loaded over 1.0 as high performance. I thought we were talking about lightly loaded canopies that were designed to be heavily loaded. According to your definition, a Katana loaded at 0.9 would not be high performance? (The original post was talking about wingloading of 0.8). I think the definition of 'high performance' has to be independent of the pilot or wingloading and has more to do with its design. Quote Share this post Link to post Share on other sites kallend 1,623 #7 November 27, 2006 QuoteQuoteYou are classifying an original (square) Sabre as high performance? Would you then say that any ZP 9 cell is high performance? Perhaps, but I am not familiar with all 9 cell ZP canopies. This may sound confusing to those who have started skydiving since 9 cell ZP canopies became common, because even higher performance canopies have been developed since, but yes, the original Sabre is high performance. The Sabre was one of the first canopy designs to be trimmed flatter than the previous generation of canopies in order to make its performance higher, (and the zero porosity fabric made it stay that way for most of its life.) Much of a canopy's suceptability to collapse due to turbulence has to do with how pressurized the cells are, so wingloading, trim angle, (and whether the canopy has airlocks) are some major factors in this. Perhaps a better way of making this warning would be to say that nearly everyone with low wing loading is at danger now that most canopies are trimmed flatter (than the previous generation of canopies) now. To diverge from the topic a bit, some of the reason that people are still hurting themselves under canopy is that they may not consider an older design like the Sabre to be "high performance" and think they are OK with one, but the Sabre is high enough performance to bite you if you are not careful. "High performance" is on a sliding scale now, with the rapid advances in canopy design in the last decade. Back to the original topic: Be careful and get educated. Take a look at the openings in the nose too. "High performance" canopies have much smaller openings than the previous generation, to reduce drag. That will also affect pressurization if they are flying slowly (as they will be at low WL).... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites pchapman 261 #8 November 27, 2006 So what exactly is or should be taught to newer skydivers about dealing with partial collapses? Countersteer to maintain heading (as much as possible without bringing the good side close to a stall), while doing a long stroke pumps of the brake on the collapsed side?? I didn't see anything about it in a quick search of the US SIM. Quote Share this post Link to post Share on other sites peek 20 #9 November 27, 2006 QuoteTake a look at the openings in the nose too. "High performance" canopies have much smaller openings than the previous generation, to reduce drag. That will also affect pressurization if they are flying slowly (as they will be at low WL). Yes! Good addition to the list of characteristics. Quote Share this post Link to post Share on other sites peek 20 #10 November 27, 2006 QuoteSo what exactly is or should be taught to newer skydivers about dealing with partial collapses? Countersteer to maintain heading (as much as possible without bringing the good side close to a stall), while doing a long stroke pumps of the brake on the collapsed side? Sounds right to me, perhaps not even multiple strokes if near the ground, but just riding it out with brakes and a good PLF. Of course prevention is the best bet. Quote Share this post Link to post Share on other sites AggieDave 6 #11 November 27, 2006 QuoteYesterday I saw someone flying her (original) Sabre loaded at maybe 0.8 and at about 300 feet her end cell rolled under and snapped back out in about a 1 second period. Since there were no "obstacles" to create turbulence at 300 feet my guess is that the heat rising from the pavement (which was slightly upwind of the column of air in which she was flying) caused this turbulence. (It was very warm in the midwest this weekend.) That and/or extreme line trim issues. The last time I've seen something like that was on an old Heatwave of mine that I sold to a jumper very very cheap on the condition that he get it relined before jumping it. Of course he jumped it and continued to jump it. He consistantly had endcell closures under canopy, not just on opening. When he *finally* sent the canopy in the inside A-lines were something like 10" short. All the lines were way off, but I remember the inside A-lines number and being surprised since they don't get the most amount of friction from the slider. People seem to forget that their canopies HAVE to be maintained. Then again, people can't even maintain their vehicle with simple things like oil changes or checking the pressure in their tires, so checking the line trim on their main canopy is out of the question.--"When I die, may I be surrounded by scattered chrome and burning gasoline." Quote Share this post Link to post Share on other sites peek 20 #12 November 27, 2006 QuoteThat and/or extreme line trim issues. Newly lined by PD canopy. I should have mentioned that. Quote Share this post Link to post Share on other sites phoenixlpr 0 #13 November 27, 2006 QuoteI thought we were talking about lightly loaded canopies that were designed to be heavily loaded. According to your definition, a Katana loaded at 0.9 would not be high performance? (The original post was talking about wingloading of 0.8). I think the definition of 'high performance' has to be independent of the pilot or wingloading and has more to do with its design. Thanks for the lesson! It seems you know lot more than me. Quote You may classify any canopy loaded over 1.0 as high performance. So what have I stated anything about any specific canopy with any specific wing load? Quote Share this post Link to post Share on other sites billvon 2,400 #14 November 29, 2006 >but yes, the original Sabre is high performance. When I got my first PD190, I was warned that I would kill myself on such a "high performance" main. Nowadays, jumpers are warned to stay on a canopy like a Nitro to learn to fly canopies before they get a high performance main like a Xaos. It's all relative; the term "high performance" has about as much absolute meaning as "bigway." >Much of a canopy's suceptability to collapse due to turbulence has to do with how pressurized the cells are . . . I don't think that's an overriding issue, though. My Nova had wide open cells, and stayed pressurized about as well as my Sabre did in smooth air. But they were spectacularly unstable in choppy air. There are a _lot_ of factors that go into what makes a canopy stable or unstable, including trim angle, nose design, cathedral etc. I think that flatter canopies can indeed be more unstable at lighter loadings - Stilettos would be a good example here. >nearly everyone with low wing loading is at danger now that most canopies >are trimmed flatter (than the previous generation of canopies) now. Is this really true? Lately it seems like steep trims are the rule rather than the exception in new canopies. It would be interesting to compare the absolute trim between, say, Stilettos and modern 'intermediate' canopies like the Pilot/Sabre 2. Quote Share this post Link to post Share on other sites phoenixlpr 0 #15 November 29, 2006 QuoteIs this really true? Lately it seems like steep trims are the rule rather than the exception in new canopies. It would be interesting to compare the absolute trim between, say, Stilettos and modern 'intermediate' canopies like the Pilot/Sabre 2. How about line geometry? From Altair: QuoteStable Elliptical: The center of gravity is centered on the wing (as compared to the Stiletto where the weight of the jumper is suspended out near the leading edge of the airfoil) this makes for high performance with consistent easy-to-control flight. Quote Share this post Link to post Share on other sites peek 20 #16 November 29, 2006 GP: ...nearly everyone with low wing loading is at danger now that most canopies are trimmed flatter (than the previous generation of canopies) now. BVN: Is this really true? Lately it seems like steep trims are the rule rather than the exception in new canopies. It would be interesting to compare the absolute trim between, say, Stilettos and modern 'intermediate' canopies like the Pilot/Sabre 2. GP: Of course, after I wrote that I started thinking... Yes, I have noticed that the Sabre 2 is trimmer steeper, and probably some other canopies too. (Maybe there is a good reason for that eh?, with those canopies expected to be used lightly loaded by many novice jumpers.) Anyway, the original Sabre is one of those to be careful with when lightly loaded. Perhaps some people can identify some others to watch out for that they know are similar. Quote Share this post Link to post Share on other sites billvon 2,400 #17 November 29, 2006 >How about line geometry? Definitely. Line geometry sets trim. Quote Share this post Link to post Share on other sites phoenixlpr 0 #18 November 29, 2006 ***Definitely. Line geometry sets trim. Quote Ok. True. I meant the position of the jumper under canopy and not specially wing's angle of attack. Quote Share this post Link to post Share on other sites Pulse 0 #19 December 1, 2006 One question I have that has not been addressed: How was the person's landing who experienced the 'tuck-under'?"Any language where the unassuming word fly signifies an annoying insect, a means of travel, and a critical part of a gentleman's apparel is clearly asking to be mangled." Quote Share this post Link to post Share on other sites jheadley 0 #20 December 1, 2006 Quote GP: Of course, after I wrote that I started thinking... Yes, I have noticed that the Sabre 2 is trimmer steeper, and probably some other canopies too. Quote PD's flight characteristics manual on the Sabre 2 says it has a flatter glide than the Sabre. Quote Share this post Link to post Share on other sites peek 20 #21 December 1, 2006 QuotePD's flight characteristics manual on the Sabre 2 says it has a flatter glide than the Sabre. If that is true then I "noticed" wrong I guess. I just seems rather steep to me, but perhaps I am used to seeing more flatter trimmed canopies land. Quote Share this post Link to post Share on other sites Pulse 0 #22 December 1, 2006 How was the landing?"Any language where the unassuming word fly signifies an annoying insect, a means of travel, and a critical part of a gentleman's apparel is clearly asking to be mangled." Quote Share this post Link to post Share on other sites LearningTOfly 0 #23 December 14, 2006 I'd make a case here that if the jumper is competent, a diving approach (front riser) to final could increase the safety margin in times of thermal activity/ turbid air/ general. More velocity^2 means more capability for Lift (N). Quote Share this post Link to post Share on other sites billvon 2,400 #24 December 14, 2006 >I'd make a case here that if the jumper is competent, a diving > approach (front riser) to final could increase the safety margin in > times of thermal activity . . . I disagree strongly. Distorting your canopy and increasing your descent rate is a very bad idea when your canopy is already being knocked about by turbulence. Front risers could be the additional perturbation that turns a buffet into a collapse. Quote Share this post Link to post Share on other sites LearningTOfly 0 #25 December 14, 2006 But what about beforehand, on a turn to final at... 250'... ok- I'm seeing a corner here- the canopy may plane out before the excess speed becomes useful. Have there been instances of swooper's canopies collapsing due to turbulence? In the interest of discussion, though: Wouldn't a higher airspeed induce a greater airpressure within the cells, which would force a greater change in airspeed (gust) to be necesary before a collapse could occur? Even if the canopy is in the process of collapsing, would applying more weight on the front risers not only increase the airspeed (air pressure) that is inflating the canopy, but also reduce the canopy's angle of attack, allowing a better angle for more air to enter? Granted, this could not be done at 'close-final' altitudes... seems that there's a critical window where Murphy could get you just because youre in the wrong lace at the right time. Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. Upload or insert images from URL. Insert image from URL × Desktop Tablet Phone Submit Reply 0 Go To Topic Listing
peek 20 #5 November 27, 2006 QuoteYou are classifying an original (square) Sabre as high performance? Would you then say that any ZP 9 cell is high performance? Perhaps, but I am not familiar with all 9 cell ZP canopies. This may sound confusing to those who have started skydiving since 9 cell ZP canopies became common, because even higher performance canopies have been developed since, but yes, the original Sabre is high performance. The Sabre was one of the first canopy designs to be trimmed flatter than the previous generation of canopies in order to make its performance higher, (and the zero porosity fabric made it stay that way for most of its life.) Much of a canopy's suceptability to collapse due to turbulence has to do with how pressurized the cells are, so wingloading, trim angle, (and whether the canopy has airlocks) are some major factors in this. Perhaps a better way of making this warning would be to say that nearly everyone with low wing loading is at danger now that most canopies are trimmed flatter (than the previous generation of canopies) now. To diverge from the topic a bit, some of the reason that people are still hurting themselves under canopy is that they may not consider an older design like the Sabre to be "high performance" and think they are OK with one, but the Sabre is high enough performance to bite you if you are not careful. "High performance" is on a sliding scale now, with the rapid advances in canopy design in the last decade. Back to the original topic: Be careful and get educated. Quote Share this post Link to post Share on other sites
drudchen 0 #6 November 27, 2006 QuoteYou may classify any canopy loaded over 1.0 as high performance. I thought we were talking about lightly loaded canopies that were designed to be heavily loaded. According to your definition, a Katana loaded at 0.9 would not be high performance? (The original post was talking about wingloading of 0.8). I think the definition of 'high performance' has to be independent of the pilot or wingloading and has more to do with its design. Quote Share this post Link to post Share on other sites
kallend 1,623 #7 November 27, 2006 QuoteQuoteYou are classifying an original (square) Sabre as high performance? Would you then say that any ZP 9 cell is high performance? Perhaps, but I am not familiar with all 9 cell ZP canopies. This may sound confusing to those who have started skydiving since 9 cell ZP canopies became common, because even higher performance canopies have been developed since, but yes, the original Sabre is high performance. The Sabre was one of the first canopy designs to be trimmed flatter than the previous generation of canopies in order to make its performance higher, (and the zero porosity fabric made it stay that way for most of its life.) Much of a canopy's suceptability to collapse due to turbulence has to do with how pressurized the cells are, so wingloading, trim angle, (and whether the canopy has airlocks) are some major factors in this. Perhaps a better way of making this warning would be to say that nearly everyone with low wing loading is at danger now that most canopies are trimmed flatter (than the previous generation of canopies) now. To diverge from the topic a bit, some of the reason that people are still hurting themselves under canopy is that they may not consider an older design like the Sabre to be "high performance" and think they are OK with one, but the Sabre is high enough performance to bite you if you are not careful. "High performance" is on a sliding scale now, with the rapid advances in canopy design in the last decade. Back to the original topic: Be careful and get educated. Take a look at the openings in the nose too. "High performance" canopies have much smaller openings than the previous generation, to reduce drag. That will also affect pressurization if they are flying slowly (as they will be at low WL).... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
pchapman 261 #8 November 27, 2006 So what exactly is or should be taught to newer skydivers about dealing with partial collapses? Countersteer to maintain heading (as much as possible without bringing the good side close to a stall), while doing a long stroke pumps of the brake on the collapsed side?? I didn't see anything about it in a quick search of the US SIM. Quote Share this post Link to post Share on other sites
peek 20 #9 November 27, 2006 QuoteTake a look at the openings in the nose too. "High performance" canopies have much smaller openings than the previous generation, to reduce drag. That will also affect pressurization if they are flying slowly (as they will be at low WL). Yes! Good addition to the list of characteristics. Quote Share this post Link to post Share on other sites
peek 20 #10 November 27, 2006 QuoteSo what exactly is or should be taught to newer skydivers about dealing with partial collapses? Countersteer to maintain heading (as much as possible without bringing the good side close to a stall), while doing a long stroke pumps of the brake on the collapsed side? Sounds right to me, perhaps not even multiple strokes if near the ground, but just riding it out with brakes and a good PLF. Of course prevention is the best bet. Quote Share this post Link to post Share on other sites
AggieDave 6 #11 November 27, 2006 QuoteYesterday I saw someone flying her (original) Sabre loaded at maybe 0.8 and at about 300 feet her end cell rolled under and snapped back out in about a 1 second period. Since there were no "obstacles" to create turbulence at 300 feet my guess is that the heat rising from the pavement (which was slightly upwind of the column of air in which she was flying) caused this turbulence. (It was very warm in the midwest this weekend.) That and/or extreme line trim issues. The last time I've seen something like that was on an old Heatwave of mine that I sold to a jumper very very cheap on the condition that he get it relined before jumping it. Of course he jumped it and continued to jump it. He consistantly had endcell closures under canopy, not just on opening. When he *finally* sent the canopy in the inside A-lines were something like 10" short. All the lines were way off, but I remember the inside A-lines number and being surprised since they don't get the most amount of friction from the slider. People seem to forget that their canopies HAVE to be maintained. Then again, people can't even maintain their vehicle with simple things like oil changes or checking the pressure in their tires, so checking the line trim on their main canopy is out of the question.--"When I die, may I be surrounded by scattered chrome and burning gasoline." Quote Share this post Link to post Share on other sites
peek 20 #12 November 27, 2006 QuoteThat and/or extreme line trim issues. Newly lined by PD canopy. I should have mentioned that. Quote Share this post Link to post Share on other sites
phoenixlpr 0 #13 November 27, 2006 QuoteI thought we were talking about lightly loaded canopies that were designed to be heavily loaded. According to your definition, a Katana loaded at 0.9 would not be high performance? (The original post was talking about wingloading of 0.8). I think the definition of 'high performance' has to be independent of the pilot or wingloading and has more to do with its design. Thanks for the lesson! It seems you know lot more than me. Quote You may classify any canopy loaded over 1.0 as high performance. So what have I stated anything about any specific canopy with any specific wing load? Quote Share this post Link to post Share on other sites
billvon 2,400 #14 November 29, 2006 >but yes, the original Sabre is high performance. When I got my first PD190, I was warned that I would kill myself on such a "high performance" main. Nowadays, jumpers are warned to stay on a canopy like a Nitro to learn to fly canopies before they get a high performance main like a Xaos. It's all relative; the term "high performance" has about as much absolute meaning as "bigway." >Much of a canopy's suceptability to collapse due to turbulence has to do with how pressurized the cells are . . . I don't think that's an overriding issue, though. My Nova had wide open cells, and stayed pressurized about as well as my Sabre did in smooth air. But they were spectacularly unstable in choppy air. There are a _lot_ of factors that go into what makes a canopy stable or unstable, including trim angle, nose design, cathedral etc. I think that flatter canopies can indeed be more unstable at lighter loadings - Stilettos would be a good example here. >nearly everyone with low wing loading is at danger now that most canopies >are trimmed flatter (than the previous generation of canopies) now. Is this really true? Lately it seems like steep trims are the rule rather than the exception in new canopies. It would be interesting to compare the absolute trim between, say, Stilettos and modern 'intermediate' canopies like the Pilot/Sabre 2. Quote Share this post Link to post Share on other sites
phoenixlpr 0 #15 November 29, 2006 QuoteIs this really true? Lately it seems like steep trims are the rule rather than the exception in new canopies. It would be interesting to compare the absolute trim between, say, Stilettos and modern 'intermediate' canopies like the Pilot/Sabre 2. How about line geometry? From Altair: QuoteStable Elliptical: The center of gravity is centered on the wing (as compared to the Stiletto where the weight of the jumper is suspended out near the leading edge of the airfoil) this makes for high performance with consistent easy-to-control flight. Quote Share this post Link to post Share on other sites
peek 20 #16 November 29, 2006 GP: ...nearly everyone with low wing loading is at danger now that most canopies are trimmed flatter (than the previous generation of canopies) now. BVN: Is this really true? Lately it seems like steep trims are the rule rather than the exception in new canopies. It would be interesting to compare the absolute trim between, say, Stilettos and modern 'intermediate' canopies like the Pilot/Sabre 2. GP: Of course, after I wrote that I started thinking... Yes, I have noticed that the Sabre 2 is trimmer steeper, and probably some other canopies too. (Maybe there is a good reason for that eh?, with those canopies expected to be used lightly loaded by many novice jumpers.) Anyway, the original Sabre is one of those to be careful with when lightly loaded. Perhaps some people can identify some others to watch out for that they know are similar. Quote Share this post Link to post Share on other sites
billvon 2,400 #17 November 29, 2006 >How about line geometry? Definitely. Line geometry sets trim. Quote Share this post Link to post Share on other sites
phoenixlpr 0 #18 November 29, 2006 ***Definitely. Line geometry sets trim. Quote Ok. True. I meant the position of the jumper under canopy and not specially wing's angle of attack. Quote Share this post Link to post Share on other sites Pulse 0 #19 December 1, 2006 One question I have that has not been addressed: How was the person's landing who experienced the 'tuck-under'?"Any language where the unassuming word fly signifies an annoying insect, a means of travel, and a critical part of a gentleman's apparel is clearly asking to be mangled." Quote Share this post Link to post Share on other sites jheadley 0 #20 December 1, 2006 Quote GP: Of course, after I wrote that I started thinking... Yes, I have noticed that the Sabre 2 is trimmer steeper, and probably some other canopies too. Quote PD's flight characteristics manual on the Sabre 2 says it has a flatter glide than the Sabre. Quote Share this post Link to post Share on other sites peek 20 #21 December 1, 2006 QuotePD's flight characteristics manual on the Sabre 2 says it has a flatter glide than the Sabre. If that is true then I "noticed" wrong I guess. I just seems rather steep to me, but perhaps I am used to seeing more flatter trimmed canopies land. Quote Share this post Link to post Share on other sites Pulse 0 #22 December 1, 2006 How was the landing?"Any language where the unassuming word fly signifies an annoying insect, a means of travel, and a critical part of a gentleman's apparel is clearly asking to be mangled." Quote Share this post Link to post Share on other sites LearningTOfly 0 #23 December 14, 2006 I'd make a case here that if the jumper is competent, a diving approach (front riser) to final could increase the safety margin in times of thermal activity/ turbid air/ general. More velocity^2 means more capability for Lift (N). Quote Share this post Link to post Share on other sites billvon 2,400 #24 December 14, 2006 >I'd make a case here that if the jumper is competent, a diving > approach (front riser) to final could increase the safety margin in > times of thermal activity . . . I disagree strongly. Distorting your canopy and increasing your descent rate is a very bad idea when your canopy is already being knocked about by turbulence. Front risers could be the additional perturbation that turns a buffet into a collapse. Quote Share this post Link to post Share on other sites LearningTOfly 0 #25 December 14, 2006 But what about beforehand, on a turn to final at... 250'... ok- I'm seeing a corner here- the canopy may plane out before the excess speed becomes useful. Have there been instances of swooper's canopies collapsing due to turbulence? In the interest of discussion, though: Wouldn't a higher airspeed induce a greater airpressure within the cells, which would force a greater change in airspeed (gust) to be necesary before a collapse could occur? Even if the canopy is in the process of collapsing, would applying more weight on the front risers not only increase the airspeed (air pressure) that is inflating the canopy, but also reduce the canopy's angle of attack, allowing a better angle for more air to enter? Granted, this could not be done at 'close-final' altitudes... seems that there's a critical window where Murphy could get you just because youre in the wrong lace at the right time. Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. Upload or insert images from URL. Insert image from URL × Desktop Tablet Phone Submit Reply 0 Go To Topic Listing
Pulse 0 #19 December 1, 2006 One question I have that has not been addressed: How was the person's landing who experienced the 'tuck-under'?"Any language where the unassuming word fly signifies an annoying insect, a means of travel, and a critical part of a gentleman's apparel is clearly asking to be mangled." Quote Share this post Link to post Share on other sites
jheadley 0 #20 December 1, 2006 Quote GP: Of course, after I wrote that I started thinking... Yes, I have noticed that the Sabre 2 is trimmer steeper, and probably some other canopies too. Quote PD's flight characteristics manual on the Sabre 2 says it has a flatter glide than the Sabre. Quote Share this post Link to post Share on other sites peek 20 #21 December 1, 2006 QuotePD's flight characteristics manual on the Sabre 2 says it has a flatter glide than the Sabre. If that is true then I "noticed" wrong I guess. I just seems rather steep to me, but perhaps I am used to seeing more flatter trimmed canopies land. Quote Share this post Link to post Share on other sites Pulse 0 #22 December 1, 2006 How was the landing?"Any language where the unassuming word fly signifies an annoying insect, a means of travel, and a critical part of a gentleman's apparel is clearly asking to be mangled." Quote Share this post Link to post Share on other sites LearningTOfly 0 #23 December 14, 2006 I'd make a case here that if the jumper is competent, a diving approach (front riser) to final could increase the safety margin in times of thermal activity/ turbid air/ general. More velocity^2 means more capability for Lift (N). Quote Share this post Link to post Share on other sites billvon 2,400 #24 December 14, 2006 >I'd make a case here that if the jumper is competent, a diving > approach (front riser) to final could increase the safety margin in > times of thermal activity . . . I disagree strongly. Distorting your canopy and increasing your descent rate is a very bad idea when your canopy is already being knocked about by turbulence. Front risers could be the additional perturbation that turns a buffet into a collapse. Quote Share this post Link to post Share on other sites LearningTOfly 0 #25 December 14, 2006 But what about beforehand, on a turn to final at... 250'... ok- I'm seeing a corner here- the canopy may plane out before the excess speed becomes useful. Have there been instances of swooper's canopies collapsing due to turbulence? In the interest of discussion, though: Wouldn't a higher airspeed induce a greater airpressure within the cells, which would force a greater change in airspeed (gust) to be necesary before a collapse could occur? Even if the canopy is in the process of collapsing, would applying more weight on the front risers not only increase the airspeed (air pressure) that is inflating the canopy, but also reduce the canopy's angle of attack, allowing a better angle for more air to enter? Granted, this could not be done at 'close-final' altitudes... seems that there's a critical window where Murphy could get you just because youre in the wrong lace at the right time. Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. Upload or insert images from URL. Insert image from URL × Desktop Tablet Phone Submit Reply 0 Go To Topic Listing
peek 20 #21 December 1, 2006 QuotePD's flight characteristics manual on the Sabre 2 says it has a flatter glide than the Sabre. If that is true then I "noticed" wrong I guess. I just seems rather steep to me, but perhaps I am used to seeing more flatter trimmed canopies land. Quote Share this post Link to post Share on other sites
Pulse 0 #22 December 1, 2006 How was the landing?"Any language where the unassuming word fly signifies an annoying insect, a means of travel, and a critical part of a gentleman's apparel is clearly asking to be mangled." Quote Share this post Link to post Share on other sites
LearningTOfly 0 #23 December 14, 2006 I'd make a case here that if the jumper is competent, a diving approach (front riser) to final could increase the safety margin in times of thermal activity/ turbid air/ general. More velocity^2 means more capability for Lift (N). Quote Share this post Link to post Share on other sites
billvon 2,400 #24 December 14, 2006 >I'd make a case here that if the jumper is competent, a diving > approach (front riser) to final could increase the safety margin in > times of thermal activity . . . I disagree strongly. Distorting your canopy and increasing your descent rate is a very bad idea when your canopy is already being knocked about by turbulence. Front risers could be the additional perturbation that turns a buffet into a collapse. Quote Share this post Link to post Share on other sites
LearningTOfly 0 #25 December 14, 2006 But what about beforehand, on a turn to final at... 250'... ok- I'm seeing a corner here- the canopy may plane out before the excess speed becomes useful. Have there been instances of swooper's canopies collapsing due to turbulence? In the interest of discussion, though: Wouldn't a higher airspeed induce a greater airpressure within the cells, which would force a greater change in airspeed (gust) to be necesary before a collapse could occur? Even if the canopy is in the process of collapsing, would applying more weight on the front risers not only increase the airspeed (air pressure) that is inflating the canopy, but also reduce the canopy's angle of attack, allowing a better angle for more air to enter? Granted, this could not be done at 'close-final' altitudes... seems that there's a critical window where Murphy could get you just because youre in the wrong lace at the right time. Quote Share this post Link to post Share on other sites
