psychonitro 0 #1 February 16, 2005 Dudes, has anyone ever heard about eleven cells canopies? I've found very little information on the Net but seems they were made. 11 cells looks like kinda a nice idea, does anyone have any further information? I think it's an interesting tech issue. Quote Share this post Link to post Share on other sites
riggerrob 558 #2 February 16, 2005 I have made hundreds of jumps with 11-cell, F-111, Strong Mighty Mack Master 520 tandem canopies. Only the best of packers could make them open comfortably. The only reason we kept them around was because they landed softly with 230 pound students. If you are still interested, I have a shiny silver, blue and pink Strong 520 with about 300 jumps and new lines for sale. PM me to discuss prices and shipping. Quote Share this post Link to post Share on other sites
skygod7777 0 #3 February 16, 2005 aerodyne used to have a AR-11 that was an 11 cell that opened really bad. icarus proto typed a 11 cell crossed braced canopy. i'm pretty sure the old racer tandem canopy was an 11 cell, it also opened bad until they put the sharkes teeth of the front of the nose to slow air getting into the canopy. for some reason most 11 cells open harder,i'm not sure why. later Quote Share this post Link to post Share on other sites
skymiles 3 #4 February 16, 2005 Icarus has an 11-cell prototype. Two weeks ago, a member of Team Icarus was jumping one (~81-84 sf I think) at my DZ. The canopy seemed to shutdown nicely for a soft landing but the swoops were not impressive. Granted, I don’t think he was pushing it. Phil Quote Share this post Link to post Share on other sites
billvon 2,395 #5 February 16, 2005 I used to jump the Strong 520 11-cell canopy. Flew OK, opened hard. I had an AR-11 160 for a little while. It always opened OK for me, but from what I've heard, that was a rarity for them. Not much difference in flying them compared to my Sabre 150. The improved aspect ratio helped with glide, but all the lines caused a lot of drag. Quote Share this post Link to post Share on other sites
SkydiveMO 0 #6 February 16, 2005 Did the Strong Mighty Mack Master 520 tandem canopies have tension knots more often then other 9-cell F-111 tandem canopies? Just curious if all the extra lines on a large tandem canopy had any effect. Quote Share this post Link to post Share on other sites
okalb 78 #7 February 16, 2005 From a performance standpoint one thing to consider is this: More cells = more lines More lines = more drag More drag = bad! -OKTime flies like an arrow....fruit flies like a banana Quote Share this post Link to post Share on other sites
larsrulz 0 #8 February 16, 2005 QuoteFrom a performance standpoint one thing to consider is this: More cells = more lines More lines = more drag More drag = bad! -OK Quite a simple concept you got there. Better tell all those 9 cell fliers to ditch their canopies for a 7 cell! If only there were nothing else going into the equation in this situation. I got a strong urge to fly, but I got no where to fly to. -PF Quote Share this post Link to post Share on other sites
okalb 78 #9 February 16, 2005 QuoteQuoteFrom a performance standpoint one thing to consider is this: More cells = more lines More lines = more drag More drag = bad! -OK Quite a simple concept you got there. Better tell all those 9 cell fliers to ditch their canopies for a 7 cell! If only there were nothing else going into the equation in this situation. Actually it is quite a simple concept. Thats why the velocity is based on a 7 cell not a 9 cell design and why PD is working on the z-brace which is based on a 5 cell design to cut down on the parasitic drag of the extra lines. I am not saying that airfoil design doesn't play a large part but most manufacturers have ruled out 11 cell designs because the positives do not out-weigh the negatives. There is a point where the benefits of the additional cells are not worth the additional drag.Time flies like an arrow....fruit flies like a banana Quote Share this post Link to post Share on other sites
SkymonkeyONE 3 #10 February 16, 2005 The APS Ranger was an 11 cell if I remember correctly. The "old" Aerodyne had the AR-11. Quote Share this post Link to post Share on other sites
togglehook 0 #11 February 18, 2005 It is a shame that people talk about things which they have no knowledge of. I study aerodynamics and a higher aspect ratio allows one to be able ro fly a smaller wing generating more speed to gain more lift thereby cancelling out the effect of more line drag. I know the Velocity holds the distance record as of now but it has been going back and forth between VX and Velo for quite a while. A lot of this depends on the pilot but if the extra line drag made that big of a difference, wouldn't PD be dominating and everybody be jumping a 7-cell? Different lines can also be used to cut down on drag. That is why many of the sponsored pilots fly HMA. SO maybe an eleven cell with HMA lines would negate the extra parasitic line drag and be the next best thing on the market. Quote Share this post Link to post Share on other sites
okalb 78 #12 February 18, 2005 QuoteIt is a shame that people talk about things which they have no knowledge of.. You know nothing about me and yet you make snide comments about my knowledge. I find it offensive and most would consider it a personal attack. Clearly the fact that you study aerodynamics means that you are the world's foremost expert on the subject. I eagerly await the release of your 11 cell swooping machine.Time flies like an arrow....fruit flies like a banana Quote Share this post Link to post Share on other sites
justinb138 0 #13 February 18, 2005 QuoteIt is a shame that people talk about things which they have no knowledge of. Quote It is isn't it. Quote That is why many of the sponsored pilots fly HMA. I was under the impression that many high performance canopies are lined with hma, etc.. because of the low trim tolerances required on small, cross-braced canopies. Aren't some of them lined with the thicker Vectran as well? QuoteSO maybe an eleven cell with HMA lines would negate the extra parasitic line drag and be the next best thing on the market. Maybe. But if there was a 9 or 7 cell x-braced canopy with the aspect ratio of this 11 cell canopy you're speaking of, why have the added drag of two extra sets of lines? Quote Share this post Link to post Share on other sites billvon 2,395 #14 February 19, 2005 >I study aerodynamics and a higher aspect ratio allows one to be able ro fly >a smaller wing generating more speed to gain more lift thereby cancelling > out the effect of more line drag. That's quite a simplification there! And it doesn't make much sense, either. You claim that 'generating more speed to gain more lift' is a good thing, but when you increase the speed, drag (from lines) goes up as speed cubed. So if you double the speed, drag goes up by a factor of eight, not down as you imply. That's why most aircraft have a best glide speed that's a lot closer to their stall speed than to their maximum speed. Also, people like to talk about "more lift." That's a misnomer. Your lift is never more than your exit weight in steady flight. If it were, you'd accelerate upwards until you broke the sound barrier. Everything remains exactly in balance in gliding flight. >A lot of this depends on the pilot but if the extra line drag made that big > of a difference, wouldn't PD be dominating and everybody be jumping a > 7-cell? 7 cells are limited on their aspect ratio. The best designs are the ones that trade off number of lines vs aspect ratio vs planform vs trim angle etc. Making those tradeoffs well is what sets PD (or Big Air, or Aerodyne etc) apart from people like you and me. Quote Share this post Link to post Share on other sites diablopilot 2 #15 February 19, 2005 QuoteYou know nothing about me and yet you make snide comments about my knowledge. I find it offensive and most would consider it a personal attack. Clearly the fact that you study aerodynamics means that you are the world's foremost expert on the subject. I eagerly await the release of your 11 cell swooping machine. Lighten up Francis.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites ALI69 0 #16 February 20, 2005 more cells = higher aspect ratio = more lift = good Quote Share this post Link to post Share on other sites billvon 2,395 #17 February 20, 2005 >more cells = higher aspect ratio = more lift = good More lines = more drag = bad Higher aspect ratio = less stability in turbulence = bad Higher aspect ratio = better L/D (potentially) = good Note that "more lift" isn't really a good goal - lift never exceeds your exit weight over the course of a jump. So the secret is to find the balance. Sometimes the canopy performs great but is unstable (the Nova) and sometimes even a 7-cell has a good aspect ratio and performs well (the Xaos-21.) Sometimes a high aspect ratio 11-cell canopy doesn't perform as well as even a 9-cell (the AR-11.) Personally I'd much rather have a Sabre 2 than an AR-11 - and my Set-400 9 cell landed much better than my old 11 cell Strong 520 did. Maybe someday someone will make an 11 cell that works well, but so far 7 and 9 cells have resulted in the better design tradeoffs. Quote Share this post Link to post Share on other sites ALI69 0 #18 February 20, 2005 *** more cells = higher aspect ratio = more lift = good More lines = more drag = bad Higher aspect ratio = less stability in turbulence = bad Higher aspect ratio = better L/D (potentially) = good Note that "more lift" isn't really a good goal - lift never exceeds your exit weight over the course of a jump. So the secret is to find the balance. ------------------------------------------------------------ Quote EXACTLY...somebody "just" need's to find the right balance.So it's good to know that somebody is trying to clear that secret. Quote Share this post Link to post Share on other sites pilotdave 0 #19 February 20, 2005 Well, lift does exceed weight for a brief period when you flare, etc. But of course you can't keep it that way and it has nothing to do with aspect ratio. But for a convincing argument why too much aspect ratio is bad for a non-rigid wing, check out THIS video of a paraglider collapsing. Higher aspect ratio generally means higher lift to drag ratio (more efficient production of lift). Thats why sail planes use extremely high aspect ratios. But a high performace swoop canopy is nothing like a sail plane. It's much more like a little aerobatic plane or a fighter plane, which both use fairly low aspect ratios. Sure, they're less efficient, but that does not traslate to slower or especially less maneuverable. High aspect ratios are appropriate to make a canopy that comes down as slowly as possible (ie a paraglider), not a canopy that's going to produce a lot of speed and maneuverability. Dave Quote Share this post Link to post Share on other sites skydiverton 0 #20 February 21, 2005 Like always in engineering you have to find a compromise. ++++++++++++++++++++++++++++++++++++++++++++ Using your droque to gain stability is a bad habit, Especially when you are jumping a sport rig Quote Share this post Link to post Share on other sites 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
billvon 2,395 #14 February 19, 2005 >I study aerodynamics and a higher aspect ratio allows one to be able ro fly >a smaller wing generating more speed to gain more lift thereby cancelling > out the effect of more line drag. That's quite a simplification there! And it doesn't make much sense, either. You claim that 'generating more speed to gain more lift' is a good thing, but when you increase the speed, drag (from lines) goes up as speed cubed. So if you double the speed, drag goes up by a factor of eight, not down as you imply. That's why most aircraft have a best glide speed that's a lot closer to their stall speed than to their maximum speed. Also, people like to talk about "more lift." That's a misnomer. Your lift is never more than your exit weight in steady flight. If it were, you'd accelerate upwards until you broke the sound barrier. Everything remains exactly in balance in gliding flight. >A lot of this depends on the pilot but if the extra line drag made that big > of a difference, wouldn't PD be dominating and everybody be jumping a > 7-cell? 7 cells are limited on their aspect ratio. The best designs are the ones that trade off number of lines vs aspect ratio vs planform vs trim angle etc. Making those tradeoffs well is what sets PD (or Big Air, or Aerodyne etc) apart from people like you and me. Quote Share this post Link to post Share on other sites
diablopilot 2 #15 February 19, 2005 QuoteYou know nothing about me and yet you make snide comments about my knowledge. I find it offensive and most would consider it a personal attack. Clearly the fact that you study aerodynamics means that you are the world's foremost expert on the subject. I eagerly await the release of your 11 cell swooping machine. Lighten up Francis.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
ALI69 0 #16 February 20, 2005 more cells = higher aspect ratio = more lift = good Quote Share this post Link to post Share on other sites
billvon 2,395 #17 February 20, 2005 >more cells = higher aspect ratio = more lift = good More lines = more drag = bad Higher aspect ratio = less stability in turbulence = bad Higher aspect ratio = better L/D (potentially) = good Note that "more lift" isn't really a good goal - lift never exceeds your exit weight over the course of a jump. So the secret is to find the balance. Sometimes the canopy performs great but is unstable (the Nova) and sometimes even a 7-cell has a good aspect ratio and performs well (the Xaos-21.) Sometimes a high aspect ratio 11-cell canopy doesn't perform as well as even a 9-cell (the AR-11.) Personally I'd much rather have a Sabre 2 than an AR-11 - and my Set-400 9 cell landed much better than my old 11 cell Strong 520 did. Maybe someday someone will make an 11 cell that works well, but so far 7 and 9 cells have resulted in the better design tradeoffs. Quote Share this post Link to post Share on other sites
ALI69 0 #18 February 20, 2005 *** more cells = higher aspect ratio = more lift = good More lines = more drag = bad Higher aspect ratio = less stability in turbulence = bad Higher aspect ratio = better L/D (potentially) = good Note that "more lift" isn't really a good goal - lift never exceeds your exit weight over the course of a jump. So the secret is to find the balance. ------------------------------------------------------------ Quote EXACTLY...somebody "just" need's to find the right balance.So it's good to know that somebody is trying to clear that secret. Quote Share this post Link to post Share on other sites pilotdave 0 #19 February 20, 2005 Well, lift does exceed weight for a brief period when you flare, etc. But of course you can't keep it that way and it has nothing to do with aspect ratio. But for a convincing argument why too much aspect ratio is bad for a non-rigid wing, check out THIS video of a paraglider collapsing. Higher aspect ratio generally means higher lift to drag ratio (more efficient production of lift). Thats why sail planes use extremely high aspect ratios. But a high performace swoop canopy is nothing like a sail plane. It's much more like a little aerobatic plane or a fighter plane, which both use fairly low aspect ratios. Sure, they're less efficient, but that does not traslate to slower or especially less maneuverable. High aspect ratios are appropriate to make a canopy that comes down as slowly as possible (ie a paraglider), not a canopy that's going to produce a lot of speed and maneuverability. Dave Quote Share this post Link to post Share on other sites skydiverton 0 #20 February 21, 2005 Like always in engineering you have to find a compromise. ++++++++++++++++++++++++++++++++++++++++++++ Using your droque to gain stability is a bad habit, Especially when you are jumping a sport rig Quote Share this post Link to post Share on other sites 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
pilotdave 0 #19 February 20, 2005 Well, lift does exceed weight for a brief period when you flare, etc. But of course you can't keep it that way and it has nothing to do with aspect ratio. But for a convincing argument why too much aspect ratio is bad for a non-rigid wing, check out THIS video of a paraglider collapsing. Higher aspect ratio generally means higher lift to drag ratio (more efficient production of lift). Thats why sail planes use extremely high aspect ratios. But a high performace swoop canopy is nothing like a sail plane. It's much more like a little aerobatic plane or a fighter plane, which both use fairly low aspect ratios. Sure, they're less efficient, but that does not traslate to slower or especially less maneuverable. High aspect ratios are appropriate to make a canopy that comes down as slowly as possible (ie a paraglider), not a canopy that's going to produce a lot of speed and maneuverability. Dave Quote Share this post Link to post Share on other sites
skydiverton 0 #20 February 21, 2005 Like always in engineering you have to find a compromise. ++++++++++++++++++++++++++++++++++++++++++++ Using your droque to gain stability is a bad habit, Especially when you are jumping a sport rig Quote Share this post Link to post Share on other sites
