billbooth

That is an excellent idea! I'll start working on it right now. Actually, the Skyhook II works the same way as the Skyhook one, with a few improvements. I have added a second Lexan cover piece UNDER the Skyhook to better protect it. It is also "sealed" differently. There are two matching holes in the Lexan pieces, in the center of the hook section. The rigger seal thread passes through both holes, around the hook, and is tied to itself. This accomplishes two things. 1. It prevents damage to the freebag bridle that could be caused by repeated piercings with a dull needle (no needle is necessary with the Skyhook II). 2. The seal thread is not loaded, and therefore NOT broken) when the Skyhook II deploys the reserve. This means that in over 90% of Skyhook II deployments, the freebag and pilot chute remain attached to the main all the way to the ground. With the Skyhook I, the number was closer to 50%. This means, unfortunately for me, fewer lost freebags. Skyhook II's are also anodized blue to make any damage more apparent, and allow laser etching of the "To Pilot Chute" warning. They are also individually serial numbered on the back with a gold holographic sticker for improved batch identification.

It seems to me that a lot of hard openings are the result of unequal inflation (one side opening first). This often sends the slider down "cockeyed" resulting in less slider drag. This can be caused by a packjob, body position, one riser catching momentarily on a reserve sidewall or riser cover, or just plain "luck of the draw". One thing is for sure, if you jump "no-stretch" lines, especially Spectra (because it's so slippery, and reduces slider drag) your chance of being injured or killed by a hard opening shock is much greater than if you jump Dacron line, which stretches just enough to absorb some of that shock before it hits you. Also be careful of too small a pilot chute. If the pilot chute drag is not sufficient to quickly and firmly pull the bag out of the container (0.6 seconds from pilot chute release to line stretch) then the bag may spin out of the container resulting in line twists. I've done a lot of tests with various size pilot chutes, and one thing seems certain...the smaller the pilot chute, the more line twists occur. While this might not cause a hard opening, on a highly loaded canopy, it could mean a reserve ride.

As I've mentioned before, it is possible that the Skyhook, even sold as a full priced option, will actually cost me money. The reason is that the Skyhook, especially the Skyhook II, greatly reduces your chance of losing your freebag and pilot chute, which cost more than the Skyhook option did in the first place. So the first time you don't lose you freebag, your Skyhook is free. The second time, it's money in the bank. I'm afraid malfunction prone jumpers could end up costing me a "fortune" because, right now, we make 1,000's of replacement freebags and pilot chutes every year.

I'll bet you know a couple of English infixes, though.

I made my first tandem on a 44 foot cargo chute back the early 1970's. Paragear had a sale on them for only $44. Who could resist? We both wore Security piggybacks, faced each other, tied our chest straps together with tubular, and connected the cargo chute to the ties. The main was "direct bag" deployed, with another jumper holding onto it in the plane (no static line necessary). A couple of other pairs also did it. On one jump, the jumper in the door of the airplane dropped the bag as we jumped, and we found ourselves in freefall right along side the still closed bag. We "cutaway" using our hook knives, and deployed our own parachutes. Needless to say, that was my last tandem for a long time. Does that count?

Please don't confuse acronyms with initialisms. TLA, for example, is an initialism. (Unless you go around pronouncing it "tlah".) If you combine all the brains on this forum, I bet we do know EVERYTHING. I've got a masters degree (obviously not in English) and I'd never heard the term "initialism". Makes sense though. (sentence fragment)

Maybe Bill should have called it RDD (Reserve Direct Deployment).... I like that. I had been calling it a MARDe System...Main Assisted Reserve Deployment.

I designed the system so that the red Skyhook lanyard is the same length, no matter what size the rig is. This is critical for the timing of the system.

I prefer to call the handles just left and right, and leave it up to the tandem instructor which one to use on any particular jump. I personally use the right on the Sigma most of the time, because its position makes it easier to pull. However, all tandem instructors should use each handle every so often, so that they remain familiar with the position of each, in case one becomes unusable for any reason.

He didn't have a Skyhook. That's the whole point of showing that particular shot. To answer the original question, no one has related a really low Skyhook story to me, but several have told me they were on the verge of passing out when they broke away, and wondered how long it would have taken them to get stable and pull.

The "good" you speak of did not appear out of nowhere. It was created by the hard work of countless individual Americans.

If you already have an RSL with a Collins' Lanyard, about half the work is done. But, we still have to add the 6" Skyhook lanyard to the RSL lanyard, sew the Skyhook attachment and cover to reserve flap 2, shorten the reserve freebag bridle, and sew the Skyhook and soft tabs to it.

I once owned one, but alas, no pictures remain. I think most people would agree, that it was the best looking PC ever.

I know I went over this before, but here it is again. Only the manufacturer of your rig can install a Skyhook on your rig, because it "alters" part of the TSOed reserve system. Your manufacturer would first have to license the technology, do the tests, and "alter" his TSO. I imagine this will happen sometime within a year.

No, I don't think that the Skyhook would have contributed to this fatality. The main reason I developed the system was to help unstable students and tandem pairs after a breakaway. As I've said before, the Skyhook places the reserve right where the main was 1/2 a second before. This simply doesn't allow a tumbling student to capture the pilot chute as appears to have happened in this incident. A conventional RSL just pulls the reserve ripcord. It does nothing to help the pilot chute get out of the way of a tumbling jumper.

What I'm curious of is how much less likely is it that a Skyhook will contribute to a fatality than an RSL (or at all?). From watching the video the Skyhook seems alot safer than an RSL, in that it appears to handle a wider range of mals safely. I design new systems to solve problems I see in existing systems. Conventional RSL's save lives, but over the years they have also contributed to a few fatalities. The Skyhook has features designed into it to solve almost every shortcoming of RSL's that I am aware of. If it didn't have major advantages over "standard" RSL's, I would have never taken the risk of introducing it. As main canopies have become more high performance, so have their malfunctions. To keep up, RSL's needed to be redesigned. It's that simple.

Edited for accuracy. Actually, I was going to say RSL instead of Skyhook, but it appears that an old style RSL may have actually contributed to one of the three fatalities.

There is a frame-by-frame shot of a breakaway from a spinning malfunction, with the jumper face to earth, on the Skyhook video at relativeworkshop.com. You will see that the test jumper rotates about 170 degrees on the horizontal axis between breakaway and opening. This is a toggle induced spin, and is probably not as violent as you might get in a real malfunction. There is also a breakaway from a spinner with the main attached to the jumper backwards. In both of these clips, notice that even while spinning, the Skyhook deploys or "places" the reserve right where the main was, in a direct line with the jumper's vertical axis, resulting the the beautifully even line groups you see. But, because the jumper is sliding, as well as rotating, a pilot chute controlled deployment, initiated at the same moment would, of course, deploy into the relative wind, or across the jumper's body, which would result in uneven line lengths at line stretch, which could cause line twists or induce a spin. As I've said before, Skyhook deployments simply look "better" and "cleaner" than freefall deployments, and this is the only way I can explain it.

I have read all 140 posts and feel I must put in my two cents. First, if you say an RSL "can't be relied on" (by which I assume you mean it might accidentally disconnect and not do its job), then you must also say that parachutes can't be relied on. Parachutes fail to open in about 1 in 1,000 deployments. RSL's are more reliable than that. Also, somewhere around 1 in 1,000 members of USPA die every year skydiving. Again, RSL's are more reliable than that. Simply put, RSL's are much more reliable than either the people who use them, or the parachutes they jump. Secondly, I am going to stop calling the Skyhook an RSL. All of the oft quoted problems RSL's have caused would NOT have been caused by the Skyhook. That's the whole point of the design. Thirdly, the only line twists we have ever filmed in the whole Skyhook test program were on the simulated total malfunction jumps, where the reserve was deployed by the pilot chute, not the Skyhook. We get letter after letter about Skyhook breakaways from BAD spinners that result in NO reserve line twists. After watching hundreds of reserve deployments on video, I can safely say, believe it or not, that Skyhook deployments, even from spinning malfunctions, yield far fewer line twists than stable pilot chute deployments. Just ten years ago, an experience jumper wouldn't be caught dead jumping an AAD, (although many of them were caught dead without one). Then the first really good AAD, the Cypres, was invented. Now everyone thinks you have a death wish if you don't jump an AAD. How soon we forget.

Go to the Skyhook Video at relativeworkshop.com. It has three such jumps from the mid 80's in it. Don't try this at home, it is more dangerous than it looks.

"When will Skyhooks be available on other rigs?" There are other rigs?

Wow! 87 replies to a post in only one day. Is that a record?

While taking children tandem is not necessarily dangerous in a physical sense, it is extremely dangerous in a legal sense, since a waiver signed by even both parents is basically worthless. So, it might be difficult to find a DZ foolish enough to let people jump without valid waivers.

I started working on the Skyhook concept 20 years ago. Two reasons it took me so long is that a Skyhook without a Collins' Lanyard is just not a good idea...especially a hard as some canopies are opening nowadays. You certainly wouldn't want a premature release of one riser (from either breakage or mis-rigging) to pull your reserve bag right into your still partially connected main. No Collins' Lanyard - No Skyhook. The other problem was total and/or horseshoe malfunctions. While it is easy to hook the main to the freebag bridle, it is very hard to make sure that connection is instantly and automatically broken in case of any type of reserve-first scenario (including, of course, AAD firing). I tried three separate times, and failed to solve this problem. The solution was the Skyhook "cam" which can not only sense force, but reacts totally differently depending on the DIRECTION from which the force is applied. This prevents accidental release when the pilot chute inflates, as it is being dragged away at the same time, and in the same direction, as the freebag. It also allows the Skyhook to release mid-deployment in the case of an attempted breakaway from a horseshoe malfunction, where the risers will initiate the reserve deployment, but cannot complete it because, for instance, your main pilot chute is wrapped around you foot. In this case, the moment the reserve pilot chute passes above the Skyhook attachment point, the cam senses that the risers can no longer continue the deployment (the pilot chute is applying the same force, but in a different direction), and releases the pilot chute to finish the job. A dimension change in the Skyhook cam of as little as 1/10 of an inch could cause a lock-up in certain scenarios. That's why we manufacture the part to 1/10,000 of an inch tolerance. A change of bridle length, or Skyhook placement on that bridle, can cause premature release during res[email]erve deployment. Luckily, the tolerance here is about a foot. The point here, is that although the Skyhook has worked flawlessly in the field for over two years now, it must be very carefully manufactured.

1. Bridle Length With the Skyhook, timing is everything. In a partial mal breakaway, the Skyhook must pull the main out of the container after the pilot chute is launched and "out of the way", but before the pilot chute begins to open and produce enough enough drag to release the Skyhook connection, like it would in a total malfunction situation. To make this equation work out with our particular pilot chute, we found that locating the Skyhook hardware 5 feet below the pilot chute, and 7 feet from the bag, gave the best results. Add these numbers up and you get 12 feet overall bridle length. "Standard freebag bridles are much longer. 2. Snap Shackle The snap shackle is the "weak point" in the Skyhook (or any RSL) system. I am having an improved shackle manufactured right now. I have made some small but important changes that I feel will will reduce the chance of accidental shackle release.