Lickablecode 0 #1 February 7, 2005 Today I added a new item to my monthly gear inspection and I thought I would share it with some of the lurking newbs (like me). Last week I jumped my old Sabre190 (which is now my sisters) and nearly broke my back on opening...seriously. Knowing that the opening might have caused damage somewhere on the harness or canopy, I decided it was best to at least look everything over before the rig is jumped again. After inspecting the canopy to the best of my ability, I moved on to check the line-trim. I found asymetric shrinking spanwise and chordwise, with the greatest shrinking on the outer A's (about 5 inches) and control lines (about 7 inches). Hard opening blamed on old lines....case closed...right? Right as I was about to stuff the canopy into a bag to send to Bill Lee, a tiny spot of pure white spectra amidst dirty brown spectra caught my eye. What I had found was that half of the circumference of the line had broken right above the bartack next to the connecting links, exposing a very small piece of the fingertrapped line. This particular area, however, is covered by the slider bumpers so I do not know if this was a preexisting condition or was the result of the hard opening. Any speculations? The canopy had silicone bumpers installed up until about 50 jumps ago. Could they have caused this type of wear on the lines? Either way I am making sure that I move/remove slider bumpers next time I do a full line integrity check. Quote Share this post Link to post Share on other sites
councilman24 36 #2 February 7, 2005 I'd be more concerned that the new fabric bumbers have a sharp edge where the fabric or thread was hot knifed. Check the fabric bumper inside and out for anything hard. I haven't seen much if any damage from silicon bumpers. And the top of the silicon bumers was probably below that point. They would have been down over the link. I can't quite tell from the pictures but if thats at the end of the inserted line of the finger trap thats a weak spot and breakage from stress might well occur there first.I'm old for my age. Terry Urban D-8631 FAA DPRE Quote Share this post Link to post Share on other sites
KevinMcGuire 0 #3 February 7, 2005 It looks to me as if the silicone bumpers had not been doing their job very well for some time. That damge looks to me as if the slider had been hitting the line right where it sat on the link every time the slide came down. Very common damage indeed. The damage was most likley missed when the swap from silicone to fabric bumpers happened. Or perhaps the damage was already present but not advanced enough to be easily spotted. The damage would then grow as a result of standard use. I would be very surprised if that damage had happened as a result of the fabric bumper. Repairing that damage is not hard and you should expect to pay around $20-$40 to repair it. Kevin Quote Share this post Link to post Share on other sites
KevinMcGuire 0 #4 February 7, 2005 Oh yeah one other thing. That damage could have been the result of many years not collapsing the slider there by allowing the slider to flap. When that happens, the grommets of the slider could cause this type of damage, but I think that this is a remote possiblity. It would take years for that type of damage to happen (unless the grommets had sharp edges), and usually the line set would have been replaced before then. Also, many other lines would have seen damage as well. Quote Share this post Link to post Share on other sites
beezyshaw 0 #5 February 7, 2005 A very common type of bumper and its installation is responsible for many lines being damaged. I'm referring to the clear vinyl tubing that you see around a lot, particularly on older canopies. This type of material is fairly thick and has a pretty hard "edge". If these bumpers are allowed to come up too high on the connector link, then as the lines are spread they make contact with the hard edge of the bumper and will eventually damage the outside lines. Many people mistakenly think this damage is from the slider grommets, but it is caused by the bumper. If your canopy uses this type of bumper, make sure that they are slid down low enough on the link that the lines don't rub against the bumpers after your canopy is open. You can just visually look at each connector link while under canopy to check for improper installation of your bumpers. The attached drawing shows a bumper that is too high on the link and would cause damage to your suspension lines. (The very soft tubing used for bumpers doesn't cause a problem, only the more rigid vinyl is the culprit.) Quote Share this post Link to post Share on other sites
KevinMcGuire 0 #6 February 7, 2005 Ah yes I didn't concider the use of the hard type of bumper. Good point Quote Share this post Link to post Share on other sites
GravityGirl 0 #7 February 7, 2005 Good point. And a nice picture too. ~~~~~~~~~~~~~~~~~ Peace and Blue Skies! Bonnie ==>Gravity Gear! Quote Share this post Link to post Share on other sites
Lickablecode 0 #8 February 8, 2005 Thanks for the help. I just realized that the bumpers that were previously on the canopy were indeed vinyl, and not the silicone type that I had previously mentioned. I replaced the vinyl bumpers with the current fabric bumpers about 50 jumps ago, and I did not notice any significant damage on the lines (I may have just overlooked that). I also made sure that the fabric bumpers had no sharp edges (running a fresh piece of spectra through the inside did the trick). After a new lineset, I might use 1.5 inch square weave for bumpers instead of the 1 inch square weave. I'm beginning to think that the current bumpers were too narrow (or tall) and accelerated the problem. How often does damage like this go unnoticed by the person who packs the main because it is hidden by the bumpers themselves? Quote Share this post Link to post Share on other sites
