Avion 0 #1 January 22, 2005 Has there been any conversions of canopies that originally came with a cascaded line set to a continuous line set? In particular, say the viability of relining a Vengence with a continuous HMA line set. Does anybody think this would work out alright, and would any changes have to be made to the slider? Quote Share this post Link to post Share on other sites
jerry81 10 #2 January 22, 2005 Well, I know a pro swooper who's relined his Velocity that way, but I can't for the life of me remember if the lines were cascaded or continuous. Quote Share this post Link to post Share on other sites
ianmdrennan 2 #3 January 22, 2005 QuoteIn particular, say the viability of relining a Vengence with a continuous HMA line set. Why would you want to ADD more line drag? I do know of a few folks, and the PD factor team jumping cascaded HMA on their velo's though. Apparently HMA is incredibly hard to cascade and bar tack well though. Blues, IanPerformance Designs Factory Team Quote Share this post Link to post Share on other sites
diablopilot 2 #4 January 22, 2005 QuoteDoes anybody think this would work out alright, and would any changes have to be made to the slider? No changes to the slider, you'll need to recalculate the lengths of the A and B lines. Not hard.....---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
diablopilot 2 #5 January 22, 2005 QuoteWhy would you want to ADD more line drag? I think the net drag would be the same, and you'd end up with a more durable longer lasting lineset.---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
beezyshaw 0 #6 January 22, 2005 I wouldn't try this at home; leave calculations of lineset lengths and trim to the manufacturers. So, my personal recommendation is if you want a great-flying canopy with continuous lines, GET A NITRO! (ok, ok, a little bit of shameless self-promotion here) Quote Share this post Link to post Share on other sites
Avion 0 #7 January 23, 2005 Ha, did I just see you at the PIA Symposium. I was at Rob's lecture on relining canopies, and I think I saw you there at the end, talking about HiPer canopies and HMA lines. It got me thinking. QuoteGET A NITRO! Brian's already got me sold on an airlock Quote Share this post Link to post Share on other sites
sundevil777 102 #8 January 23, 2005 I don't think you have the info to calculate it.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
Avion 0 #9 January 23, 2005 Quote Why would you want to ADD more line drag? I do know of a few folks, and the PD factor team jumping cascaded HMA on their velo's though. Apparently HMA is incredibly hard to cascade and bar tack well though. I like the idea of having continuous lines if one breaks or has to be cut, less over all effect on the rest of the canopy. I only want medium performance, so the wind drag addition will probably be negligable to me. HMA is so thin it would probably be too small to notice anyway. QuoteNo changes to the slider, you'll need to recalculate the lengths of the A and B lines. Not hard..... Seems like, its really a factory question. To recalculate the length, I would need a design reference. Thanks Quote Share this post Link to post Share on other sites
diablopilot 2 #10 January 23, 2005 Sure I do.....---------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
sundevil777 102 #11 January 23, 2005 You would need more than just the lengths for the uncascaded version (such as some angles). Does the mfg supply info like this? It might be better to just measure a canopy that is too new to have suffered from shrinking.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
Avion 0 #12 January 23, 2005 What I would need is a dimensional reference between the the riser links and the attachment tapes. I might possible to figure it out by measuring a existing cascaded line set and then doing some math. But, I think it would be better to use a design print or CAD data. This would be proprietary data. Quote Share this post Link to post Share on other sites
davelepka 4 #13 January 23, 2005 If you're looking for any kind of perormance, go with what the mfr is doing. As far as safety, I've had line breaks at high WL and landed the canopy without a problem. More to the point, if safety is your concern, why would you switch to HMA? What about Dacron? Adside from absorbing opening shock, they will last forever. What are you jumping now? What are you looking fir in a new canopy? Quote Share this post Link to post Share on other sites
Avion 0 #14 January 23, 2005 Dacron stretches out trim after a while, right? 500-800 jumps. Also, dacron increases pack volume, with an air lock, already more volume plus dacron lines, it might be a significant increase. I like Dacron for reserves, where the shock of a high speed deployment would be softened, and only hopefully a few uses would be far less than enough to stretch the lines out of trim. My impression is that HMA is the latest step in lines with reduced drag. First, Spectra less drag and stretch than dacron, but supceptable to heat shrinkage. Then Vectran, heat resistant but supceptable to abrasion. Now HMA, less drag(thinner), heat and abrasion resistant, and been reformulated to be more UV resistant. So, if your going to reline anyway, why use anything but dacron or HMA? Why were the lines cascaded in first place? To reduce pack volume? HMA is already so thin, a continuous set would only be slightly larger than cascaded spectra and smaller than cascaded dacron. Since, I will be asking only moderate performance from my canopy, I am looking for airlocks, only a slightly eliptical form, and have basically decided on a Lotus, the added drag I doubt will be an issue. So, I guess it comes down to preference. I'd use a continuous dacron line set, but it would pack HUGE The only liability I see of having continuous lines is that there are more of them to possible snag on something. Quote Share this post Link to post Share on other sites
davelepka 4 #15 January 23, 2005 Seriously, I don't know what 'moderate' means. To me, moderate is anything under 1.9 to 1 WL, but above 1.6ish. Everything under that is low performace. Again, what are you looking to do here? Do you want moderate flare performance? Moderate glide? Are you swooping? What is your current wing, and what changes are you looking for? What aspects of your current canopy are lacking, in your opinion? Without knowing your frame of reference, it's hard to answer your questions accurately. What size Lotus did you demo in relation to what you have now? What was the lineset on the demo you jumped? Have you discussed the line issues with Brian Germain? My guess would be he'd be the final word on any of this. Quote Share this post Link to post Share on other sites
mattjw916 2 #16 January 23, 2005 QuoteI'd use a continuous dacron line set, lol, try reselling that canopy... I'm sure if there was a tangible advantage to the other linesets people like PD and Brian Germain would use them. BTW, I still would love to demo a Nitron... maybe later this year contigent upon my currency.NSCR-2376, SCR-15080 Quote Share this post Link to post Share on other sites
sundevil777 102 #17 January 23, 2005 QuoteWhat I would need is a dimensional reference between the the riser links and the attachment tapes. I might possible to figure it out by measuring a existing cascaded line set and then doing some math. But, I think it would be better to use a design print or CAD data. This would be proprietary data. It is not a matter of doing math. It is a matter of not having enough info. Having the length of the A line and the length of B line with the point of attachment along the A line is not enough. The A line doesn't go straight on a cascaded line set. So what angle would you assume, what 'angle of attack' should the canopy be, you can't calculate it without more info. If people want to do it, they should get info from the mfg or just measure a good example.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
Avion 0 #18 January 23, 2005 Having: 1) The length of Line A from the AB cascade to the canopy, 2) The length of line B form the AB cascade to the canopy, 3) The length between the line A attachment point and the line B attachment point, 4) The length between the AB cascade and the riser link. It would be possible to calculate the lengths necessary to fabricate continuous A and B lines. However, doing such reverse engineering may introduce slight errs that could make the canopy fly off heading or react differently to similar right and left toggle input. I doubt any company would release figures without first testing the resulting line set. So, it might be hard to get an useful answer from a manufacturer. Once big companies get used to doing things one way, they tend to keep going that way. HMA is new, and I presume HiPer is also fairly new compared to PD and BigAirSportz, and is trying to get its share of the market by being on the cutting edge of technology, rather than relying on a reputation. The other big companies will probably migrate to using HMA in time, if it continues to stand up to its claims. I'll send Brian and PD a note. I just thought it might have already been done. Quote Share this post Link to post Share on other sites
Hooknswoop 19 #19 January 23, 2005 Quote Dacron stretches out trim after a while, right? 500-800 jumps. No, it doesn't. QuoteMy impression is that HMA is the latest step in lines with reduced drag. HMA is very difficult to cascade. I have heard that continuous HMA lines have a little more drag than cascaded Vectran. Lines are a tremendous source of drag. Look at cables on bi-plane aircraft, they aren't round, but flat to reduce drag. Round cables/lines have a lot of drag and I don't know of any way to keep flat lines correctly orientated to reduce drag. Derek Derek Quote Share this post Link to post Share on other sites
Spizzzarko 0 #20 January 24, 2005 There are a lot of people out there who use dacron. Look at most tandem canopy's out there. They are lined with Dacron. Look at the crew canopys. They are lined with DAcron. Just because it is older and a lot of the manufacturers are not using it any more, doesn't mean it is a bad product.. Do you even know why manufacturers are using Vectran and HMA now? These materails don't shrink or stretch like dacron or spectra. With high performance wings, line length and trim is very important. The best opening canopy that I have ever seen and have ever jumped is a spectre 170 with dacron lines. Quote Share this post Link to post Share on other sites
sundevil777 102 #21 January 24, 2005 QuoteHaving: 1) The length of Line A from the AB cascade to the canopy, 2) The length of line B form the AB cascade to the canopy, 3) The length between the line A attachment point and the line B attachment point, 4) The length between the AB cascade and the riser link. It would be possible to calculate the lengths necessary to fabricate continuous A and B lines. It is not possible with that information. You have determined the dimensions of the triangle above the cascade point, that is true. When you figure out at what orientation that triangle needs to be (related to the angle of attack of the canopy) relative to the A line below the cascade then you will be able to solve for the overall length from attachment to riser for a non-cascaded set.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
masterrigger1 2 #22 January 24, 2005 *** -------------------------------------------------------------------------------- Quote -------------------------------------------------------------------------------- Dacron stretches out trim after a while, right? 500-800 jumps. -------------------------------------------------------------------------------- No, it doesn't. Quote Oh but yes it does. We have know that for years.The center cell lines stretches further than the rest along with the brake lines. You can check it on any dacron lined canopy that has 400 or 500 jumps on it for positive verification. MELSkyworks Parachute Service, LLC www.Skyworksparachuteservice.com Quote Share this post Link to post Share on other sites Hooknswoop 19 #23 January 24, 2005 QuoteYou can check it on any dacron lined canopy that has 400 or 500 jumps on it for positive verification. I had an old Star Trac I with a bunch of jumps on it and it was still in trim. Derek Quote Share this post Link to post Share on other sites Avion 0 #24 January 24, 2005 This is why I mentioned that a design reference would be best. By using the both AB and CD lines in order to determine the orientation of the triangles, I imagine a reasonable value for all the continuous lines could be evaluated. Even then the shape of lower edge of the ribs will also have to be taken into consideration, in order to get an accurate figure. I'm familiar with engineering, I'm just new to skydiving Quote Share this post Link to post Share on other sites sundevil777 102 #25 January 24, 2005 QuoteThis is why I mentioned that a design reference would be best. By using the both AB and CD lines in order to determine the orientation of the triangles, I imagine a reasonable value for all the continuous lines could be evaluated. Even then the shape of lower edge of the ribs will also have to be taken into consideration, in order to get an accurate figure. A 'design reference' isn't just best, it is required. You are no more able to determine the non-cascaded CD lengths than you are the AB. It won't help.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am 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
Hooknswoop 19 #23 January 24, 2005 QuoteYou can check it on any dacron lined canopy that has 400 or 500 jumps on it for positive verification. I had an old Star Trac I with a bunch of jumps on it and it was still in trim. Derek Quote Share this post Link to post Share on other sites
Avion 0 #24 January 24, 2005 This is why I mentioned that a design reference would be best. By using the both AB and CD lines in order to determine the orientation of the triangles, I imagine a reasonable value for all the continuous lines could be evaluated. Even then the shape of lower edge of the ribs will also have to be taken into consideration, in order to get an accurate figure. I'm familiar with engineering, I'm just new to skydiving Quote Share this post Link to post Share on other sites
sundevil777 102 #25 January 24, 2005 QuoteThis is why I mentioned that a design reference would be best. By using the both AB and CD lines in order to determine the orientation of the triangles, I imagine a reasonable value for all the continuous lines could be evaluated. Even then the shape of lower edge of the ribs will also have to be taken into consideration, in order to get an accurate figure. A 'design reference' isn't just best, it is required. You are no more able to determine the non-cascaded CD lengths than you are the AB. It won't help.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
