billbooth

Isn't that more of an axiom than a law? Mick. Hey! Murphy got a LAW...I want one too! Besides, it's easier to spell than axiom or principle.

I agree. I don't advocate anyone cutting away at 100 feet. For all the reasons I have stated above, there is so much error in trying to determine how high you actually are, especially when you are losing altitude rapidly while spinning, that 250 feet may not actually be enough. When I heard about that 100 foot breakaway stunt those base jumpers had done, I just shook my head and said: "You've got to be kidding!" I show the video just to demonstrate how quickly the Skyhook can get a reserve to line stretch...with the most dramatic background possible....the ground. I would breakaway below 500 feet only if I was very sure I was going to die if I didn't...a situation I hope I am never in. Hell, I get nervous deploying my main much below 3,000 feet. Remember Booth's first law: " The lower you pull, the more likely you are to have a malfunction."

A static line deployed base rig starts off with "0" airspeed, while a breakaway from a gliding main already has a lot of airspeed. This significantly speeds up deployment time. But, like I said, my distance calculations are only estimates from video. Whatever the real number is, the fact remains that a Skyhook will get your reserve open faster than a pilot chute by a long shot...and I've read a lot of reports of people without RSL's going in at line stretch. It seems that quite often, every foot counts.

We can ESTIMATE the distance from breakaway to "open" reserve if we know the initial descent before breakaway, and the time to a "fully open" reserve. It is hard to directly measure this distance using pressure sensing devices because the rapid change in body position during opening shock, as well as the shock itself, tends to make such readings unreliable. Estimates from watching video of Skyhook deployments seem to indicate breakaway to "fully open" reserve can take as little as 70 feet, with average sized, normally packed, sport equipment. At this point the reserve is fully inflated, but we don't really know how "survivable" a landing at that exact moment would be...and volunteers willing to find out have so far been rather scarce. The major problem with this "how high do I have to be when I breakaway?" argument is that skydiving altimeters are not all that accurate, and there is always some amount of time, and therefore lost altitude, between making the decision to breakaway, and actually doing it. (Hell, just the time it takes to look at your altimeter could easily cost you an additional 100 feet.) Plus, depending on how fast your main is spinning, and how long you have been riding it, your ability to respond quickly may have been seriously compromised. At the end of our Skyhook video, a very experienced jumper, with previous breakaways, takes a full 5 seconds from the time his hands leave the risers (decision time) until he finally locates and pulls his breakaway handle. He then takes four more seconds to locate and pull his reserve! So, he was well above 1,000 ft. when he decided to breakaway, yet he was only about 10 feet above the ground when the reserve actually opened. And please remember, the main purpose of the Skyhook was "better" reserve openings. Faster is only a side effect.

Yes.

On my first hand deployed rig, I used a bight of pilot chute bridle through a bungee cord loop which held the container shut. Then came the nylon coated steel cable "flex-pin". The curved, solid steel pin was just the last refinement in that thought process...ie, the container should stay closed until the pilot chute pulls it open. About the 3-ring...There are only three simple machines that produce mechanical advantage...the pulley, the inclined plane (or screw), or the lever. I knew that to be practical a single point release had to have a MA of about 100-1. Pulleys didn't have enough MA, and tended to lock up. Screws were expensive and complicated to control, and also jammed easily with sand. As I remember, the three rig release was at least my fifth or sixth try at it. It solved all the problems evident in my earlier designs. Round "levers" that flipped through each other were simple, couldn't mis-align, and allowed wide tolerances, so were are difficult to jam. Most importantly, they were cheap. The first working prototype of the 3-ring release system cost me under $100 to build...compared to the millions it might cost do develop a release like the Capewell it replaced. You might also notice that the nylon coated steel cable from early hand deploy experiments was put to good use on the 3-ring. The "pud" handle, believe it or not, took me the longest time to figure out. I originally used soft housings for the cable, but that led to hard pulls, so my early customers had to literally steal the cable off pay phones if they wanted the 3-ring option. Luckily, I found a supplier before anybody went to jail...but it was damn hard to find a working pay phone in DeLand for a while. The Skyhook is another invention I worked on for years before I could finally figure it all out. As usual the answer came to me in a dream...where everything is possible. So you might say that I do all my best work in my sleep. I still remember waking up at 2 in the morning with the finished "3-ring" design in my head, and heading immediately to the shop, literally in my pajamas, to put the first one together. It was really cold (for Florida) outside in my suspended harness, but I must have hooked the damn thing up and broken away, a hundred times before I could go back home to bed.

Trouble is, double-ended 3-ring release loops drastically lower the reliability of the 3-ring system...as we have found out on tandem drogue release systems. Plus, if your 3-ring cables jam, you can't pull your reserve ripcord. So by linking the two systems, you lower the reliability of both. This is hardly a system you want to give to a student jumper...is it?

Two points: 1. The very deep ("rock and roll", "tail-below-the-nose") brake setting on RWS 360 tandem reserves, along with other design features, was the only way we could insure these canopies could open "softly" at tandem terminal (170 mph) Remember, your tandem reserve has no drogue. It has worked well for over 20 years on thousands of canopies. 2. Line twists are not a big problem on most reserve opening situations. However, if you have line twists AND unequal line lengths, caused by an unstable body position (body not aligned properly into the relative wind) then you could have a serious problem. Unequal line lengths, caused by one shoulder being "lower" than the other, when added to several line twists, cause by the bag being pulled "sideways" out of your reserve container, could cause an unrecoverable spin (just like the one you probably just broke away from). The chance of this happening on your reserve depends on the shape and wing loading of your reserve canopy. If reserves keep getting smaller, and take on higher performance elliptical shapes, this will become more and more likely. The reason I went through this rather long winded explanation, was to point out the difference between breaking away from a spinner with a "normal" RSL, and with a Skyhook. While the normal RSL will allow the pilot chute to deploy your reserve canopy "into the relative wind" and possibly "across" your body, causing unequal ine lengths, AND line twists, as the reserve comes out of the bag, the Skyhook "places" your reserve right where your main was 1/2 a second earlier, or exactly in-line with the vertical axis of your body, greatly lessening the possibility of both line twists and unequal line lengths.

In almost all cases, freefall pilot chutes do their job in under 1 second, so whether they oscillate doesn't really matter, does it? As was said above, adding an apex vent would: 1. Make them open slower, 2. Make them harder to manufacture, and 3. Make them more bulky...none of which would be very helpful.

But if they really covered the rings, you wouldn't be able to breakaway.

When I put them on the first Vector 1, some of the jumpers in my shop thought they were excessive, or at least an unnecessary decoration...kinda like the "mud flaps" on an old "Pimp-mobile". So they called them mud flaps too, probably just to make fun of me. I actually put them there to cover up, and protect the main ring stitch pattern from sunlight or abrasion. Can anyone think of a better name? I've never really appreciated the joke.

My very first Vector (1979) was designed with a "hand deploy/pull out reserve. That 1" space just inboard of the closed riser covers was for the Velcro path to the reserve pilot chute pocket or handle (in case the pull out version worked better). After considerable testing, I determined (with the help of almost everyone who test jumped it) that a pull out reserve was hard enough to use correctly on a planned deployment, and absolutely unthinkable in a panic situation. And, as was stated above, in incompatable with any sort of AAD. This is just one of many ideas (like a second reserve pilot chute) that I have tested and rejected in the past.

I'm sure you've seen the "trick" where someone pulls the table cloth out from under a fully set table so quickly that all of the plates, silverware or glasses remain undisturbed and in place. This can theoretically happen if too much force is applied too quickly on a reserve free bag. The bag and pilot chute depart, leaving the still packed reserve in the pack tray. Line dump is a similar phenomena.

Let me answer both questions. At first I worried that the Skyhook would put "too much" force on the reserve bridle, causing a bag strip in certain extreme situations, like an accidental main deployment on the tailgate of a C-130, that broke the right main riser, and caused the Collins' lanyard to breakaway the left riser, resulting in a both fully open, and "fast" main canopy dragging out the reserve bag via the Skyhook. To make sure this would not happen, I did drop tests from PD's tower to determine how much force was necessary to cause a bag strip, then designed the red Skyhook lanyard to break before that force could be applied. That's why it breaks at 400 lbs.

I believe woomera is aborigional for "really bad idea". Mick. I couldn't stop laughing for 5 minutes...Good one!

In the case of a breakaway from a partial malfunction, the Skyhook system initially supplies a force of about 120 lbs. on the reserve bridle. If the canopy does not come out of the bag instantly, that force will quickly build up to about 400 lbs., and then the RED Skyhook lanyard (not the freebag bridle) breaks. So, if a snatch of 400 lbs. will clear the reserve bag lock, then the Skyhook will instantly solve the problem. ( For reference, a reserve pilot chute pulls about 120 lbs. at terminal, and much less immediately after a breakaway) If a rigger left a packing tool in the reserve packjob, then the Skyhook will not help. The Skyhook can also prevent a bag lock by getting the freebag out of the container, and to line stretch, so quickly and positively that the bag cannot possibly tumble through the lines, or get wrapped up in the bridle, thus eliminating one "major" cause of bag locks. This could be an especially important feature if you have a pilot chute hesitation, and the freebag bridle wraps around the pilot chute, choking it off, and preventing it from doing its job in a timely manner. These are not "pie in the sky" scenarios. I've seen each of them happen before. Ask yourself a simple question: Would you rather have just one device (your reserve pilot chute) deploying your reserve, or have 2 devices (your reserve pilot chute AND your departing main canopy) competing for the honor. Over the years, I've watched literally hundreds of breakaway videos, with and without a Skyhook. From what I've seen, the Skyhook doesn't just deploy a reserve faster...it deploys it "better". After all, "Better" was the main purpose of the design. Faster is only a "side effect". Take a look at the "Skyhook Video", and you'll see what I mean.

But I cheated. No drogue...same experienced passenger...3,000 exit...no packing.

I'll say it again, If you want to get rid of "line-overs" and drastically lower your chance of nearly every other kind of partial malfunction on tandem mains...the answer is very simple...flat pack.

We spent the money for two reasons: 1. In theory, it cuts manufacturing errors, thus saving re-manufacturing costs. I'll let you know how that works out in practice in a couple of years. 2. If you want to sell to government, you've got to do it. As much as I hate paperwork, it still hurt to spent the money.

Gee! I'm glad to know I just spent nearly $100,000 0n NOTHING.

You're right. I remember that now. The Racer chest strap back then (I don't know how they do it now) was just wrapped around the main lift web like a confluence wrap (not doubled around it like Vectors or Javelins). So it simply unwrapped on a hard opening.

I don't know of a fatality from a broken, or too loose chest strap, so I guess it's not much of a problem. I do know of people falling out of harnesses when they don't thread strap correctly, or at all.

I am referring to the MS-70101. It is simply a lot stronger than its "rating". The breaking strength of most adapters never comes into play, because they slip way below their rating. I say most, because the MS-70101 is the exception. It won't slip at all. It distorts just above 2,000 lbs. and the breaks at around 2,500...with some variation between manufacturers. When we high speed or tower drop test, we use a hard rubber dummy with all straps tightened as much as possible. Unfortunately, the dummy cannot compress and/or bend like a real human, but it's the best we can do...that is unless YOU would like to exit an aircraft at 500 feet, at 210 knots, with a few extra hundred lbs. strapped to your body.

The MS-70101 may have a "rating" 500 lbs., but luckily it is "good for" well over 2,000 lbs. Your chest strap usually doesn't take much load. but if you jump "no-stretch" line and have a one-sided opening, it can load pretty heavily, and at an angle. I have seen MS-70101's cut half way through a single type 8 chest strap on such an opening (without damaging the hardware, by the way). That is why we have been using double type 8 for many years now.

It takes 8-10 seconds after throwing a drogue at tandem terminal (170 mph), for it to slow you down to 120.