billbooth
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Everything posted by billbooth
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One Type-17 mini-riser will break at about 3,500 lbs., when new. Spectra lines for parachutes come in several strengths, from 425 to 1,500 lbs. It is more common to break a single line (or a link) than a riser. I have never seen a situation where all the lines on a riser broke, and left the riser intact. What is important, is that the harness below the riser is stronger than the riser. The main riser is designed to be the "fusable link", which "protects" everything else, including your neck. An intact riser, with a broken main lift web (or neck), won't do you much good, will it?
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Not enough.
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Should there be underage skydiving?
billbooth replied to pacncathyjr's topic in General Skydiving Discussions
A waiver signed by a parent, for a child, is absolutely useless in a court of law. No DZ owner in his right mind would let an adult jump without signing a waiver. When you let someone under 18 jump, no matter who signs the waiver, THERE IS NO WAIVER. It is not "dangerous" to jump with children. I jumped my daughter Katie into the North Pole for her 12th birthday. It is just unwise to do it commercially in the US. -
Funny you should mention that...About two years ago I had a bad spinner on a prototype tandem canopy. The "G's" were so high that I didn't even have to pull the breakaway handle. I just unhooked the Velcro, and the weight of my arm did the pulling for me. It happened so fast that it caught me off guard. (I was planning to pull slowly enough to get an idea what the pull force was...Data...I need more data!) Anyway, we were flung so hard to the side, that the reserve opened horizontally instead of vetically. Point is, the weight of your arm in a high "G" mal can actually help you breakaway.
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You got it. It's the little things that count.
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There is little or no reason, or benefit, to take a newbie tandem student on a night jump. Night jumps are simply more dangerous than day jumps, so we discourage them.
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I just went back and did a side by side pull test with our standard mini riser and the Miniforce riser. The set-up was a single riser, with the yellow cable through a short stainless housing. Here are the results (average, 3 tests each weight): 250 lbs. load - Standard = 2.0 lbs / Miniforce = 1.0 lbs. 500 lbs. load - Standard = 3.0 lbs. / Miniforce = 2.0 lbs. 750 lbs. load - Standard = 5.0 lbs. / Miniforce = 3.5 lbs. 1,000 lbs. load - Standard = 8.0 lbs. / Miniforce = 6.0 lbs. So, if a 200 lbs. jumper was spinning at 5 "G's", (500 lbs. on each riser) the miniforce riser equipped rig would require 2 lb. less pull force to breakaway...or 4 lbs. vs 6 lbs., plus housing friction. I doubt the average jumper would be able to tell the difference.
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Looks like the guy in the picture should have stowed his excess brake line in the slider stops, and solved two problems at once! PS: I'm Kidding!
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Sadly, I think most people choose a reserve based solely on price and pack volume. That's because most people believe that there is no performance difference in reserves. Which, by the way is not true.
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Did she have an SOS system? These require a very long pull, and sometimes small people have to use two hands.
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I understand these military "problems" were on cutters used in cargo drops and de-reefing applications, not in AAD applications. AAD's are used so infrequently, that this kind of problem would take a long time to show up. The cutter blades could have been put in place 90 degrees out of sync, or they might have rotated upon firing. I don't know. For whatever reason, these military units asked for a cutter that this particular problem COULD NOT happen with. The company which designed and patented this improved design, provides cutters for the Vigil.
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Good idea! I'm re-naming it the anti-fart, pucker factor AAD. A great design always has unseen fringe benefits.
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Correctly stowing excess brake line is a very big deal. Several jumpers have recently lost their lives because of this problem. When we went from Velcro to non-Velcro toggle keepers, several manufacturers made no provision for excess line stowage. I think this was a very bad idea. I believe everyone has published some sort of stowage instructions by now...or at least I hope so.
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The Cypres cutter blade is a single-edged knife, designed to cut the loop in one place, at 90 degrees to the loop. The Vigil cutter blade is circular, so it does cut the loop in two places. This was done because IF a single-edged blade rotates 90 degrees, it will cut the loop lengthwise (down the middle), possibly not releasing it. I understand that this has happened in some NON-CYPRES military applications, prompting the design of a circular blade, that cannot become mis-aligned. I have NEVER heard of it happening on a Cypress.
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Having both yellow cables the same length is no guarantee of a simutaneous cutaway, UNLESS your long cutaway housing does not compress. There are two types of cutaway housing available...compressible or extensible (stretchable). You should make sure whoever manufactured you rig used housings that don't compress more than 3%, but stretch to absorb opening shock. If the force required to move the yellow cable through the riser loop exceeds the force necessary to compress the housing, then the long housing will get shorter, and throw off release timing. This is just one primary problem with "soft" housings...they have no rigidity and compress easily...and they don't stretch at all.
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I once saw a guy pull his reserve at terminal because his main pilot chute tied itself in a knot. When we retrieved the reserve freebag, we also found a overhand knot right in the middle of that bridle. The poor guy had two bridle knots on one jump. Luciky, the knot in the reserve bridle did not affect the pilot chute function. To prevent main pilot chute knots, always pack the bridle inside the pilot chute pack job, up against the mesh, and throw the pilot chute hard to the side in one swift motion, letting go as soon as you reach arm extension. If your bridle never gets above your pilot chute. you cannot have a bridle knot, can you?
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Soft housings are always a bad idea. However, the "Partial - soft" housings on the Flexon are the best soft housing out there.
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The MS-70101 chest strap buckle is only "rated" at 500 lbs., but it goes to over 2,000 before failing. It is also the most slip resistant buckle ever invented...even when it is made out of stainless. The first thing that ought to break on a super hard opening is your main risers. However, as long as people insist on jumping "no-stretch" lines, there is no telling what's going to go first.
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All you have to do is pull the cutaway handle 6-7" release your main. No matter how small you are, surely you can do that. Keep your 3-ring cables lubricated, don't use soft housings, do use riser inserts, and above all, pull high, and you'll never have to worry about any of this. Simply keep your gear in good shape, and cutaways will be quick and easy. Trust me...I've done dozens of 'em. (Luckily, only 5 for real.)
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I think you guys need a variation of one of my first inventions..."The Pucker Factor AAD". It's quite simply really. First you tie a lead sinker to a long piece of line, and swallow it. When it comes out the other end, you attach it to the small end of a solid cone. You then cram the cone us your ass, and tie the other end of the cord (which is hanging still hanging out of your mouth) to your reserve ripcord handle. If you get scared enough, the pucker factor will squeeze out the cone and activate your reserve. No batteries or pyrotechnics, and its self-calibrating. Whadda ya think?
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After pulling you breakaway pud, your left hand should have only one job to do...to pull your reserve handle. If it's busy "clearing" breakaway cables, it can't do that job in a "timely manner", can it? Also, reaching across your chest with your left hand is going to do nothing to aid your stability during reserve deployment. I designed the 3-ring to be activated with one hand, specifically so that your brain (and left hand) could concentrate on that reserve handle. If you use two hands to breakaway, you have effectively defeated the main purpose of the design, and might as well go back to Capewell releases.
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Skydiving on the Today show, Monday May 2nd
billbooth replied to johnny1488's topic in General Skydiving Discussions
Ann Curry's "out" landing got more coverage on the Today Show this morning...actually pretty good coverage. Sometimes everything just "works out". -
Pilot chute in tow malfunctions with a BOC hand deploy are very rare indeed nowadays...perhaps less than 1% of all malfunctions on hand deploy rigs. Totals from "floating dildos" and improper packing on pull-outs (according to a lot of non-scientific data I've gathered over the years) seem to represent about 5% of all malfunctions on pull-out rigs. Floating dildos ARE a very dangerous malfunction, because you know you can find that dammed handle any second now.....if you just keep trying.....SPLAT! Quite a few very experienced jumpers have met their maker while performing this dance. Both systems work. BOC's just work better (about 5 times better) for most people.
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First Cutaway - Story & Questions
billbooth replied to inzite's topic in General Skydiving Discussions
I suspect a pilot chute problem. Read some of my previous posts about how to tell if your pilot chute is correctly made, and functioning properly. A good pilot chute ought to pull nearly 100 lbs. at terminal. That much force would easily clear any pin you could get into your closing loop, and just as easily pull out any bag you could get into your container..no matter how tight. With a proper pilot chute, time from pilot chute release to line stretch should not exceed 3/4 of a second. -
All theory aside...on average, people who jump pull-outs, have 4 or 5 times more total malfunctions than people who jump BOC hand deploys. This is not to say that for any particular, very careful packing individual, a pull out is more dangerous. Many people can go hundreds of jumps with no problems. However, I don't see any advantage that a pull out system gives, that is worth the added risk of total malfunctions.