Hooknswoop

I started thinking about how the largest and the smallest containers of a particular model have the smae size reserve PC. Theoretical: Take two identical jumpers, same speed, altitude, weight, etc, deploy same type of reserve at smae altitude, except one is 100 sg ft and one is 200 sq ft. they fire the reserve at the same time. Because the PC's are the same size, the smaller reserve will come out of the D-bag sooner. assuming they inflate at the same rate(sq ft / sec), they would both inflate to 100 sg ft at the same time. the difference being the 200 sq ft canopy would be only 1/2 open. So which reserve would open faster? this isn't a quiz, i don't have the answer, but we have some pretty high speed people on this forum that could provide some great insite. So how about it? Hook

alan- thanks :-) "I'm still learning alot about canopies" Me too. The more I learn, the more I realized how much I don't know. Hook

Alan- very ingenious, mind if I steal that one? Hook

Levin- Very nicely put, thanks. I have said my keep and promise not to bring it up ever again. Hook

Kill line pilot chutes are a high wear part of your skydiving equipment requiring periodic inspection and maintenance to ensure that they will continue to function properly. Pilot chutes are deployed at 120 mph, lift the bag off your back, then it rapidly collapses as the canopy leaves the bag, and finally they are dropped onto the ground with each landing. Who hasn’t been walking back to the packing area to the calls of “dragging!”, only to discover you have been dragging your pilot chute across the ground? Kill line pilot chutes wear at several points. The following is what to inspect and some suggestions for increasing the life span of your kill line pilot chute. The Spectra kill line shrinks from the heat generated from sliding through the bridle as the pilot chute collapses and the bridle stretches over time, affecting the original calibration. Because the change is so gradual it often goes unnoticed until you begin to experience hesitations on deployment. To check for correct kill line length, cock the pilot chute and watch the kill line. Does it become taunt before the two white ribbons that run from the apex (the top of the pilot chute) to the bridle? If it does, then the kill line is too short, not allowing the pilot chute to completely inflate. When cocked, the two white ribbons should be taunt and there should be some slack on the kill line. Also, if the handle of the pilot chute being pulled through the small opening at the base of the pilot chute on deployment, the kill line is too short. Your rigger should be able to replace the kill line, or if the kill line was manufactured with enough excess line, your rigger can simply extend the kill line. Check the stitching that holds your handle to the pilot chute. If the handle rips off, you would have a total malfunction. Check the bridle, especially where the pin attaches to the bridle. If any of the stitches have come out, have your rigger repair it. If the pin rips off of the bridle you would have a pilot chute in tow malfunction. As you fly your canopy, the deployment bag is free to spin around the bridle. Eventually the bridle will wear out and break at the grommet. Have your rigger use waxed nylon cord to tack both sides of the rapide link to the reinforced part of the deployment bag to prevent the bridle from rotating in the grommet. Some manufactures sew the pilot chute bridle to the deployment bag, eliminating this problem. The disadvantage of a sewn-in pilot chute is they are difficult to replace, usually a job for a rigger. Lastly, have your rigger install stainless steel rapide links instead of the plated links. They won’t corrode, reducing wear on the bridle. Whether your pilot chute is a kill line or not, the Z-P or F-111 fabric wears just like the fabric on a canopy. The porosity of the fabric degrades with use, decreasing the drag of the pilot chute. Eventually the pilot chute will not have enough drag to deploy your main canopy, leaving you with a pilot chute in tow or a bag lock. An indication that your chute may have problems is a pause between throwing your pilot chute and the canopy coming out of the bag. A patch on a pilot chute would be difficult to sew and could cause it to spin on deployment, creating lines twists. As the mesh wears, holes will develop. Once the mesh tears the hole will become larger quickly. Replace a pilot chute with holes in the fabric or mesh. Checking your pilot chute every time you do your 30-day three-ring maintenance is simple and could prevent a malfunction. If you are not confident inspecting your pilot chute, have your rigger help you. An ounce of prevention is worth a pound of cure. Hook

I haven't re-packed the reserve from the last time, geez, give me a break :-) Hook

Sorry, got side tracked :-) back to the question: would an F-111, say a PD-190 glide the same as a 0-P lets say, triatholon 190, all other things being equal? I honestly don't know, but I would put my $$$ on the F-111, 9-Cell outgliding the 0-P 7 Cell. Not very helpful, but it couldn't be that hard to find two people w/ the same size canopys, one an F-111, 9-Cell and the otherr a 0-P, 7-Cell w/ the same wing loading and roughly the same # of jumps on each and fly them end cell to end cell and see which one out-glides the other. Any test-jump volunteers? Hook

----i'd be willing to come protect you gals from the locals---- But who will protect the locals from the girls?????? Hook

"7 Cells tend to open very snivelly" Most reserves are 7 cells, and they don't snivel. Base canopys are 7 cells and definately don't snivel. I wouldn't characterized 7 cells as snively. Some are, some aren't, same as 9 cells. Hook

And still stood it up, damn kids:-). Swoop pond or not, I shouldn't have gone over there w/ kids around. Hook

If I couldn't carve away I would pop up enough to clear over them. If they were very close, I would pop up hard and yell "Call 911" because I am probably going to get hurt. If I could still walk afterwords, I would scream at the mother until horse, or her hair came off, whichever comes first. I think the landing area is no different than a freeway, who's fault would it be if an unsupervised child ran out onto I-5 in California and was hit by a car? Hook

I think flying a small canopy takes on a certain responsibility. Because the canopy I fly is so much faster than 99% of the canopys I usually share the sky w/, any collision would be my fault. I have seen people that fly small canopys yell at other people for "screwing up their set-up" for their hook turn. No one owns the sky and if you fly a small canopy you should have to take on more responsibilty for maintaining clearance from other canopys. A sabre 190 is a sitting duck and has zero chance to avoid a collision if I come out of a hard turn in their direction. So clearance is up to me. If someone can't deal w/ traffic and blames other people (that are below them and can't see someone setting up for a hook above them) for getting in the way, they should turn in their rocket for a manta because they aren't ready to fly or at least hook that canopy. My opinion. Hook

The smaller the canopy, the larger the effect 3 inches out of trim would make to the performance. A manta 288 that is 3 inches out of trim won't be affected nearly as much as a crossfire 89 that is 3 inches out of trim. That is why the small canopys usually have vectran lines. It would be nice if manufactures would recommend a maximum tolerance for each size canopy. Maybe a percentage across the board for each type of canopy. Hook

"I honestly don't see this incident as being even remotely the DZ's fault. " Either do I. Hook

Can someone be TOO safe? I don't think so. I always touch my handles more than once in the plane. Most of it is just to make me feel good about my gear. If I touched my handles 3 seconds ago and I or anyone near me hasn't moved on the plane, they couldn't possible be out of place, but I'll double check them anyway. It's nice to have a warm fuzzy about my gear before I exit so I can focus on the skydive. Another thing I do at a new DZ is to walk the swoop lane. Since I usually slide at the end of my swoop, I am looking for any uneven ground that could twist my ankle or knee. I try to find a smooth patch of ground and look for areas to avoid. I picture my approach and options. usually at least one load will land during this time allowing me to be sure my approach will fit in with the normal traffic or have to change it. Hook

I've seen a lot of mains deployed unstable too. I think the reason a reserve could blow up is not related to size, but to speed and weight. I have heard, but don't know this to be true, that small reserves are stronger than large reserves. Somethng about less space between re-inforcing. It would be interesting to know if small or large reserves are stronger. I am not advocating small reserves for everyone, only similar reserves to their mains or be aware and accept that a large difference in performance between a small main and a large reserve could cause serious problems in a two out situation. Education and informed decisions is my goal. Hook

Does anyone think that a Stiletto 97/Tri 160 would not be a good test of a small main/large reserve combo? Hook

The mechanic in question is not an A & P or pilot of any sort. I never said anything about a jumper being injured. I let the USPA know about it. I was told there was nothing they could do. Next step is the FAA. I did not want to do that. Involving the FAA will affect the percieved ability to police ourselves. I am sure my comments have reached the DZ in question. It is very possible that with these comments being made public, that things will change. If I do nothing, what does that make me? Hook Hook

Heck, I walked up to manifest at DZ I had jumped at before and tried to manifest to do a hop and pop. The manifest chick said I needed to do get w/ an instructor. I tried to explain to her that I had done a hop and pop before and that it was OK, but she refused to listen to me. I finally had an instructor friend of mine, (who was trying not to laugh), tell her that it was OK for me to do an un-supervised solo hop and pop. I don't think she ever figured out that I had over 2700 jumps............ Hook

I would like to use at least a 143R or larger..... Hook

What does everyone look for, check on and do when going to a new DZ? Landing area, obstacles, etc. This started in Swooping and canopy control under "Dealing w/ Traffic". Kind of a new DZ checklist for jumpers. Hook

Good idea, will do:-) Hook

The construction of my VX is not any stronger than my reserve. It doesn't have spanwise re-inforcement. I put 831 jumps on an FX-70 loaded at 2.6, no problems, why would a small reserve blow up so easily? Hook

My main is not reinforved as much as my reserve is. I can't think of a single main that is reinforced more than a reserve is. My VX opens as hard as my reserve does about half the time. Most reserve deployments are sub-terminal, all 11 of mine have been. I will do some checking on hard numbers, but I don't believe F-111 is stronger that 0-P Hook

There wasn't an A & P on the DZ, and if the jumpers are paying someone, the pilot has to have a commercial rating. Hook