RemiAndKaren 0 #1 January 8, 2002 A while ago, I remember (but cant find) that we had a discussion about the possibility of a main pack job being so tight that it could cause a PC in tow... I challenged it, but got a few comments back saying it was a possibility , so I let sleeping dogs lie... Well, just got the lastest Skydiving, and there goes TK Donle explaining that the tightest RW was able to pack their Vector caused a pull force of about 15 pounds.... way below what any PC would create (80 pounds was quoted for a standard one)... in summary, if you close it by hand, it will open.So there you go... I'm waking up the sleeping dogs... If you have a PC in tow (I'm not atlking about hesitations here), its probably a rigging/packing error.RemiMuff 914 Quote Share this post Link to post Share on other sites
DBTECH 0 #2 January 8, 2002 I totally agree with TK on his numbers presented--I've always said that PC's in tow are caused by bridle routing factors, not tight closing loops.We've left one cause out here--and that is an actual pilot chute malfunction, which again, is usually bridle related-(as rare as it is)Dave Brownell Quote Share this post Link to post Share on other sites
skreamer 1 #3 January 8, 2002 What about kill-line PCs not being cocked? I noticed that hasn't been mentioned, or isn't it relevant to this discussion?Will Quote Share this post Link to post Share on other sites
jfields 0 #4 January 8, 2002 QuoteWhat about kill-line PCs not being cocked?I'd put that under the "packing errors" category. I think they are saying that without packing errors, a closing loop can't be tight enough not to pull out.Certainly, a non-cocked pc won't create as much drag as one that is functioning properly.....JustinMy Homepage Quote Share this post Link to post Share on other sites
Craig 0 #5 January 8, 2002 What about the tightness of the bag IN the container? I had a PC in tow that cleared as I was reaching for emergency handles. The closing loop was very tight, coupled with a bag that was fitting very tightly in the container. It was the first jump on my new Mirage G3. Yes, the PC was fully inflated at what sure looked like to be full extension when I glanced over my shoulder to see what was up. The next pack job fit better and closing force was less, but (as I now know from continued jumping on the rig) it still towed a little longer than deployment that has taken place on any of the following jumps. BTW on that second jump on the rig I was sure to really launch the PC into the airflow. Just another thing that may be of importance. The rig came with a spectra closing loop that would stretch after a few pack jobs.Craig Quote Share this post Link to post Share on other sites
Aviatrr 0 #6 January 9, 2002 Quote Well, just got the lastest Skydiving, and there goes TK Donle explaining that the tightest RW was able to pack their Vector caused a pull force of about 15 pounds.... Thanks to the curved pin, the forces really can't be anywhere near the drag created by a good PC..I wonder if some of these new "power closing tools" allow you to close a container in such a way that it would cause a much higher required force to extract the pin?Mike Quote Share this post Link to post Share on other sites
riggerrob 558 #7 January 9, 2002 There is one other malfunction mode that none of you mentioned. If you stuff too much bridle, too deep, it can hook around the corner of the stiffener on the bottom flap. The resultant pilotchute in tow is scary, but it usually clears itself about the time you peel your release handle off your harness.Careful packing can prevent this malfunction, but the best solution is the bridle hider flap on the latest Javelins that prevents you from stuffing the bridle too deep. Quote Share this post Link to post Share on other sites
dove 0 #8 January 9, 2002 I was SO worried about this a few weeks ago. I had been demoing a Spectre120 just before I had to get my reserve repacked. So I took the demo out and brought my rig and triathlon 150 to the rigger. He repacked the reserve and put the main back in without changing the closing loop. It was freakin' tight! I was scared it wouldn't come out but another rigger assured me it would. I was so ready to chop but it was just like usual. Amazing what that little fabric balloon can do!dove Quote Share this post Link to post Share on other sites
flow 1 #9 January 10, 2002 QuoteI was SO worried about this a few weeks ago.Me too, as I have 150 square foot canopy in a container meant for 135, and the closing loop is tight, really tight. I tried once to pull it open by hand and I do have to say after that, I was sure it won't come open in the air. Quote Share this post Link to post Share on other sites
des 2 #10 January 10, 2002 a combination of a s`hort bridle,worn p/c and a tight pack can also cause a p/c in tow. des Quote Share this post Link to post Share on other sites
RemiAndKaren 0 #11 January 10, 2002 Quotes`hort bridle,worn p/c tight pack job or not, its a bad set up waiting for an accident to happen....RemiMuff 914 Quote Share this post Link to post Share on other sites
riggerrob 558 #12 January 10, 2002 A simple check is to try and pick the rig up using the main bridle.The pin should pop and the d-bag should come loose.Since most rigs weight less than half the pull force of a healthy pilotchute, this test should dispell any fears. Quote Share this post Link to post Share on other sites
SpeedRacer 1 #13 January 10, 2002 My closing loop is tighter that $%^#, especially in the winter when the air is dry, I have a bitch of a time getting it closed. Yet I've never had a problem w/openings.Speed Racer"My God! It's full of stars!" Quote Share this post Link to post Share on other sites
alan 1 #14 January 10, 2002 QuoteJust another thing that may be of importance. The rig came with a spectra closing loop that would stretch after a few pack jobs.That is odd. One of the properties of Spectra is that it is more dimensionally stable than Dacron or the gutted 550 that is commonly used for main closing loops. It is less resistant to damage from heat though and is more likely to shrink than stretch. Typically, the standard reserve closing loop that comes from the mfgr is Spectra because it doesn't stretch, among other reasons. The CYPRES loop is Spectra. It has not been widely used as a main loop because it is so easily damaged by the friction heat generated by someone zipping out a pull-up chord.alan Quote Share this post Link to post Share on other sites
DBTECH 0 #15 January 10, 2002 Alan said--That is odd. One of the properties of Spectra is that it is more dimensionally stable than Dacron or the gutted 550 that is commonly used for main closing loops. It is less resistant to damage from heat though and is more likely to shrink than stretch. Typically, the standard reserve closing loop that comes from the mfgr is Spectra because it doesn't stretch, among other reasons. The CYPRES loop is Spectra. It has not been widely used as a main loop because it is so easily damaged by the friction heat generated by someone zipping out a pull-up chord.DB> You beat me to it--I totality agree with your post. I'm using 1000lb Spectra for a main closing loop, because of it's stability and longevity. And yes, I never withdraw a pull-up cord without first bringing it under the pin, to avoid heating the Spectra. BTW-I use a 550lb Spectra 'loop' for a pull-up cord. (17" laid flat)-works great.Dave Brownell Quote Share this post Link to post Share on other sites
Craig 0 #16 January 10, 2002 QuoteThat is odd. One of the properties of Spectra is that it is more dimensionally stable than Dacron or the gutted 550 that is commonly used for main closing loops. It is less resistant to damage from heat though and is more likely to shrink than stretch. Typically, the standard reserve closing loop that comes from the mfgr is Spectra because it doesn't stretch, among other reasons. The CYPRES loop is Spectra. It has not been widely used as a main loop because it is so easily damaged by the friction heat generated by someone zipping out a pull-up chord.The only reason I mad a comment about the stretch was because I had heard of "pre stretching" the CYPRES closing loops. This got me thinking that if the main closing loops were not pre stretched that there could be a possibility for them to lengthen just slightly after a few pack jobs. The material is larger (1000Lb?) that the CYPRES variety though, not really sure of the qualities between the two strengths.Craig Quote Share this post Link to post Share on other sites
riggerrob 558 #17 January 12, 2002 Guys,Let's go for the simplest possible explanation: the knot takes 3 or 4 pack jobs to "set." Quote Share this post Link to post Share on other sites
DBTECH 0 #18 January 12, 2002 A figure 8 knot is better for this purpose, compared to an overhand knot.Just my 2c worthDave Brownell Quote Share this post Link to post Share on other sites
