KellyF

Ray Ferrell shared a similar concept with me a few years back that he called the "snatch force"

We use a piece of 3/32" music wire that's about 10" long that has a semi-blunt point ground into it as a corner turning tool. It's long and slender enough to get under the work without having to lift/angle the work too much.

Since we've gotten multiple emails about this topic today, I'll throw my response out here for any curious Infinity owners, with a little bit more information since I lost my train of thought while composing the email to those that inquired today While it is OK to route the bridle from the bottom of an Infinity container, one should be careful to ONLY route the bridle under the #2 flap, and OVER the #1 flap. Tucking the bridle under the #1 flap could lower the security of the main pin cover flap and introduce premature wear. What interests me is that until about 6 years ago, I had never heard of this malfunction happening. I believe it has become more prominent due to skydivers wanting every part of their gear “tight and tidy”, including the bridle under the pin cover flap- tucking it in so tight and orienting the pin in such a manner that the bridle can start moving before the pin does, giving the bridle an opportunity to impale itself on the pin. Social media is also making it easier for people to share the information, possibly making a mountain out of the proverbial mole hill. I would hope that the free flow of information on the web is the main culprit here and that we're not actually regressing with our knowledge of knowing how to pack properly Any routing/stowing of the bridle should be done so that any movement of the pilot chute end of the bridle results in either the pin extracting, or more slack in the bridle between the tip of the pin and where the bridle enters the main container.

Do you have an AAD? If so, what kind, and where is the cutter located on your Next?

Hi Peter, I wanted to create the most labor intensive reserve PC on the market Actually, the idea was to create a pilot chute that inflated quickly at any angle between upright and laying on it's side. In order for the pilot chute to be able to inflate (partially) on it's side, the canopy fabric needs to extend below the equator (where most pilot chutes have the seam connecting the mesh to the canopy fabric). This creates a pocket to capture the air and start inflating the pilot chute. The mesh portion allows more airflow into the canopy and aids in inflation at odd angles. I am certainly not ignoring Newton. In addition to embracing Newton I am applying micro timming to the process. What loads when. The PC loads the bridle which loads the bag. The lines will load next as they have less mass than the canopy. The lines are now pushing against the velcro and the safety stow is trying to retain the bight but it can't because there is no tension on the bight on that critical side. The canopy loads after this because it is bigger and has further to go. Assuming we're talking about a belly to earth deployment (since thats the way these systems are intended to be deployed, and to eliminate infinite variables and scenarios), as the bridle loads the bag and tries to turn it 90°, the parachute will most certainly see an acceleration force before the lines in the stow pocket, since it occupies the full length of the bag, and the stow pocket only about the bottom 50%. As the bag bends, it immediately starts trying dump the canopy out of the mouth of the bag before the lines see ANY acceleration. Again, the lines are easier to accelerate than the canopy because they have less mass. They are not going to load before the canopy because they can't- they're in the same bag. As explained above, the canopy can see the acceleration force before the lines, but not the other way around. The "worst case" scenario is the bag getting pulled parallel to the pack tray, in which case the canopy and lines will see an acceleration force at the same time- but the lines, having less mass than the canopy, will be easier to accelerate and more likely to move with the bag than the canopy. I disagree with this comment. You may not be able to catch the actual moment the lines dump out of the pocket, but the evidence would be clearly visible IF it happened. Look at it this way- lets say it takes 1/5 of a second (6 frames of video) for the bag to go from the3 container to line stretch. I think we agree that line dump is most likely to happen as the bag is getting snatched out of the container, right? So that leaves at least 5 frames of video to show either a messy wad of lines floating between the bag and container and/or the lines going directly from the locking stows into the container where the rest of the lines presumably are. I'm not even addressing the possibility of bag strip, since the result of that would be VERY apparent, even to the naked eye since there would be an empty freebag floating down and nothing else outside of the container.

John, Newton's first law of motion applies to the parachute thats IN the freebag as well as the lines that are in the stow pocket and safety stow, which you seem to be ignoring. In fact, since the lines have less mass than the parachute itself, they are easier to accelerate (decelerate)to the speed of the pilot chute than the parachute itself is. What this means is that upon initial snatch from the pilot chute, the parachute is trying to fall out of the bag (it's at rest in the container). The only thing keeping it in the bag is the closing flap and safety stow, which will stretch and create a tighter grip on the bights of suspension lines. There will be no line dump from the locking stows unless the safety stow breaks. Lets say that all of the lines DO dump out of the stow pocket. That could only happen after the bag has moved a minimum of 6" or so (the distance from having the lines inside the pocket vs. outside the pocket). This would mean that the parachute has also moved (or at least tried) 6" inside the bag, toward the open end, loading the closing flap and locking stow. Now, you're stating that the mass of the lines falling out of the pocket is going to pull a bight of line out of the safety stow, but unless all the lines from the pocket are stuck together, the only time the bight in the safety stow will have the full weight of those lines on it is at line stretch. Think about it- try to pick up an entire coil of rope while only holding one end of the rope... I've packed for, and videoed drop tests with standard safety stow freebags with both "high drag" and "low drag" (to use your terms) pilot chutes at 240 knots (276 mph) with not a HINT of what you're implying is a common occurance in a terminal (120 mph) reserve deployment. Thats all I've got to say about that. /Forrest Gump BTW, the Infinity reserve pilot chute is about 75% fabric, 15% mesh, and 10% open at the base of the spring.

Ralph Hatley has a box of them. Give him a call 503-630-5867. They're priced like gold, too

There's a few contributing factors, which is why it has taken as long as it has to issue a service bulletin, and why we're essentially dealing with the cutomers on a case by case basis. We don't feel that this is a grommet tooling issue, since the sharp edges that we've seen on the cutaway housing grommets have been formed over the course of many jumps, in at least 3 different locations on the grommets. BUT the wear issue is not only caused by sharp edges on the cutaway housing grommets, so please inspect your risers and get in touch with VSE if you have any concerns

Isn't that a matter of how the cover flap is designed? Ie Wings style main protection doesn't seem to suffer as the canopy gets smaller (at least within reasonable limits).... That is correct. Our pin cover and the "up-tuck" style covers work for the same reason, it's just not as apparent with ours. With the "up-tuck" style, the stiffened pin cover is always going to be longer than the distance between the hinge and the pocket, so it makes sense that it would stay tucked in when you look at it. The main downside to that style of pin cover is that it takes very little effort to open it should something get underneath it.

That is a horrible generalization to pass on to a newbie. So very much wrong with that. It's reality. I'd much rather see some one get a rig that can accomodate what's likely to happen than get a less tolerant rig, be short on funds so they don't buy a smaller rig when they run out of closing loop, and have their smaller main fall out in the plane (seen that in person, it's a little scary) or on their way out (seeing a main fall out in the plane is scary because I've seen pictures of skydiver sized holes in the side of planes and "exciting" videos with plane + main entanglements). I'd also much rather see some one get a rig with a safe sized main now that'll accomodate two sizes smaller than a parachute one or more sizes smaller than conservative because the rig they want will only go one size smaller or a rig that starts out on the small size which has them delegating to packers who won't be quite as attentive to things like frayed steering lines as an owner packing their own rig. The reason we locate the closing loop on the bottom flap instead of a tab at the base of the reserve container is for the security of the main pin cover flap. Tuck tabs require specific geometry to function properly, and locating the closing loop on the bottom flap ensures that the hinge point on the pin cover and the edge of the main top flap that it has to line up with are always in alignment. If you have the closing loop attached at the base of the reserve container, that allows the main top flap to "float" up or down based on the length of the closing loop, messing up the critical alignment of the hinge and edge of the flap. So yes, you can downsize more with the loop anchored near the reserve container, at the expense of pin protection, so I wouldn't say that one style is "safer" than the other when it comes to putting smaller canopies in them than they were designed for. One other thing to think about when it comes to downsizing- people will be a lot more likely to downsize if all they have to buy is a new canopy. If they have to buy a new canopy AND harness, maybe they won't be downsizing quite so quickly, presumably becoming a better canopy pilot with their current (larger) canopy

I think it's getting about time to start differentiating between the Skyhook and any other type of MARD that may be being discussed. The Skyhook is a MARD, but a MARD is NOT necessarily a Skyhook. Of all the incidents where the Skyhook has been involved over the past 10 years or so that I know of, only two would have had the same outcome if another MARD had been involved- Morten Pedersen's reserve baglock that he fought free, and the other guy in DeLand that had his RSL misrouted. All of the other ones have been complicated by the specifics of the Skyhook- most notably the red seal thread that holds the lanyard to the hook, and the Collin's lanyard. Both of those features make a Skyhook equipped rig behave differently than the majority of the rigs in use in some circumstances.

Thanks Jerry

I assume by "inverted" you mean invented.... INVENTED by Jerry????

Alexy, IMO, you should not put the small pocket on the bridle. Jerry and I disagree on this, but the the fact is it only makes for a little bit neater packing, but it WILL cause the pin to bend during a high speed malfunction/cutaway. This is because it prevents the RAX from rotating when the reserve PC takes over during the deployment.

From what I can make out of the drawing in the facebook link, it looks more like it's based on Eric Fradet's concepts where the straightening of the bridle pulls a pin and disconnects the RSL.

Again, I respectufully disagree. I was thinking it was about 6 frames to linestretch, Lee says about 5, but we're also talking different projects, so I'm in the ballpark. If it takes 6 frames of video for the bag to cover the ~10 feet of the length of the lines, and the lines come out of the pocket, you WILL see a wad of uncontrolled line somewhere between the bag and the container. True, you may not actually SEE the MOMENT the lines dump out of the pocket, but you'll know if it happened or not. These tests were done with 300+ sq.ft. canopies, maybe close to 400. I don't remember the details of the canopies. One very interesting thing I DO remember that supports my point above is that the meshless PC's we were using had an interesting "failure". They would not start to pressurize until the bridle was loaded (naturally), but at the moment the bridle was loaded and the air entered the PC, the blast would hit the plate at the top of the spring, stretch the spring, then pop the tacks holding the plate to the spring, THEN the PC would fill and pressurize and lift the canopy out of the container. You could see it all frame by frame at 30fps. There was no damage to the PC canopy itself. The plane was a B-25 and the drops were at 500'.

But how big is the envelope? I've filmed traditional safety stow deployments at 240 knots with no hints of line dump or bag strip. I may be repeating myself considering this thread is over 5 years old, so pardon the echo if I am

Come on Kelly, I did it years ago. I have published the maximinum extraction force for any Racer and my pilot chutes are placarded with the "Effective Size". If the pilot chute won't pull it out the extraction is to high. If I can do it so can everybody else. It's simple to find out what your drag is and limit anything over that. You don't even have to test the container. If you don't have to test the container, how do you know if it has acceptable extraction forces? Quick numbers off the top of my head, as far as determining compatibilty between a particular brand of canopy and our 14 different shapes/sizes of reserve containers, I come up with 252 tests for each model of canopy, PLUS the 6 months between packing and doing the extraction tests (although this could be accelerated). So multiply that number by all the different reserve canopy models out there, and you can see why I don't think what you're asking is realistic. BTW, I don't think marking the PC with an "effective size" or Cd tells the rigger anything about if it will pull the canopy out of the container. All that information does is give riggers (or anyone else looking for a PC) a way to compare one PC vs. another.

Nope, I'm just resting here on my laurels and the billions of $'s that I'm making building custom harness container systems for the sport skydiving market While I don't completely disagree, I DO think it's a nearly impossible standard to set due to the shear numbers of canopy/container combinations, packing methods (stuffed or empty freebag ears?), and the time involved in getting accurate data since a freshly packed canopy will be easier to extract than one that's been packed for a few months. The best way to get the data in any quantity is for riggers in the field to do the tests and submit the info, but that can only get us part of the story, since it would be hard to consistently asses the firmness of the ears of the canopy when you have so many different people doing the evaluations. Back on topic though, I have yet to hear of a situation where a MARD failed to extract the bagged reserve from the container.

I disagree when it comes to the sport market and square parachutes. A round parachute that relies on the suspension lines around it's perimeter to create drag will certainly struggle to create the roughly 50 lbs. of drag required to pull the reserve pins via the RSL. And can you explain that last line? Are you seriously concerned that a riser will block the airstream from a reserve PC more than the jumper's body? The same standard that you think the MARD's should be tested to John, the TSO standard. Never mind that there AREN'T any TSO standards in effect for MARD's at this point, and you seem to be implying in your post that the TSO standard doesn't mean anything anyway. So really, what's the point of your thread? I think you said it best a couple pages back John: No, compatibility is AN issue, it is certainly not the the ONLY possible cause for the incidents that prompted that advisory. You yourself recommend a head high attitude when deploying a reserve parachute, yet we have documented cases where jumpers give up and get in a nice stable belly to earth body position and wait for their AAD to save them. We both know that that is the best position to be in if you want to create a nice big burble to stick a spring loaded PC to your back for a second or two, and at AAD activation altitudes, that's all it's going to take to kill the jumper. NASA Ames charges about $6000/hr for tunnel time. It's a good thing you were able to piggyback on your refueling drogue tests, huh?

Sorry, I was just going off what I thought I had read a week or so ago. I scanned the thread to find the post, but didn't take the time to read through the whole thing. No mal intet intended

The easy way would be to sew the velcro in the pocket down only along the edge of the pocket closest to the handle. I woulld sew some 1" Ty-3 to the velcro first to give it some strength though.

John, can you answer these questions in regards to Racer/Tandem Racer. For the first 3 questions he doesn't have to answer. Those questions were asked because the malfunctioned main actually plays the role of the reserve PC on systems with MARD. To replace the reserve PC with the malfunctioned main, you have to know what pull force this main can produce in the worst case scenario. Why not? Doesn't a malfunctioned main on an RSL equipped Racer have to have enough drag to separate from the harness and be able to pull the ripcord pins? Let me put it this way: MARD or RSL, either system has been tested to be able to pull the ripcord pin. What happens AFTER that is a bit different. The main on the RSL rig should fly away completely separate from the jumper and reserve deployment system. The MARD will, AT THE VERY LEAST pull out the reserve bridle and get the reserve PC off the jumper's back (this is assuming the malfunctioned main can't pull the bagged canopy out of the container, which seems to be what John is hanging his hat on). So at that point, you STILL have a reserve PC that is capable, tested, and CERTIFIED to do the job of extracting the freebag from the container. There IS nothing holding it back, preventing it from doing it's job. The main canopy DOES NOT REPLACE the reserve PC. I think John is barking up the wrong tree here. There are scenarios where the Skyhook doesn't behave the way I think it should. They fall outside of the TSO testing guidelines, but not outside of the real world. Didn't someone in this thread say that Bill or UPT said they had about a 10% premature release rate during testing? That is roughly what I've heard from various riggers in the field. If there was any other piece of skydiving equipment that failed to do it's intended job 10% of the time, NO ONE would buy it and it would be deemed a spectacular failure.....

From what I saw in the Video you don't need it. Your pilot chute launches and obviously drags and your bag extraction force is low. MARD are for rigs who have a lously pilot chute launch which has low drag anyway and with bag extraction forces which allow the rig to be swung around by the bag bridle. John, again, that is not an Infinity in the video. Not at all, I am saying that when a MARD link attaches to the reserve bridle with intent to prempt the reserve bag extraction function. It is acting as a reserve pilot chute and should be tested as such. Yes, the main pilot chute should be Certified in this case. Additionally, its drag capability should be documented along with the max allowable container extraction force. That's mathmatical proof of system function. The components which link the main pilot chute to the MARD link should be certified to bridle standards. I tend to disagree. If you're going to have a spec for a minimum drag capability for the main PC, what about a spec for the maximum amount of drag that is allowable before a high speed, high drag type of malfunction causes a problem further down the chain of parachute components? How much is too much? I don't think anyone has the answer, given the wide range of parachute sizes and weights. This doesn't mean that the MARD concept is flawed, however. I've got many thoughts on all of this, but it's hard to sit down and type them all out in a coherent and timely manner. In the videos I clearly see one riser attached to the rig (what you are calling RSL, so be it) the other or off side riser is perpedicuular to the streamer line, the lines are spread and all that stuff flying around scares me. I know you talked to the guy in Deland, didn't something like that happen to him? I don't know what exactly caused Morten's reserve baglock, but I feel confident that it had nothing to do with a rigging error, and I don't think there was any entaglement of the main with the reserve. I SUSPECT that the elastic nature of the risers, RSL, lanyard and reserve bridle caused enough of a rebound that the bagged reserve got inverted enough to let the bridle partially wrap around the reserve lines at the mouth of the bag. This is pure speculation on my part though. How perceptive of you to understand the function of the length of reserve ripcord as the governing factor. That a first for the industry and I am not being snide, Imean it as a compliment. However, the instulation of the incorect ripcord would violate the TSO. I can't fix stupid. Thanks for the compliment

John, just to be clear, that video of the RAX testing has nothing to do with an Infinity- that is not our rig, not our PC, just a concept that I shared with Jerry and he tested it. There has not been an Infinity rig built with a MARD at this point. It seems to me that you're making the argument that a MARD creates an "out of sequence" deployment, at least until the reserve PC is doing some of the work. Would this not be the case then if a reserve PC got entangled with a jumper and the wide reserve bridle actually did what it's intended to do and deployed the reserve? The bridle is preempting the reserve PC just as a MARD would, but since the bridle is a certified component it's OK? MARD interlocks should NEVER be placed close enough to the reserve bag to allow the PC to interfere with the bagged canopy. If it were positioned so that the PC could get under the bagged canopy, I would tend to agree with you. Your notion of having a "flailing riser" doesn't make a whole lot of sense to me, so let me see if I'm following you correctly. You're implying that the non-RSL riser could hang up and interfere with the deploying reserve? Short of the RSL side riser breaking below the RSL connection (yea, yea, we all know- every RSL system should have a cross connector....) the only reason I see where someone might have a "flailing riser" would be from a lazy cutaway and improperly trimmed cables. But that's OK, since it falls into the "user error" category, right? In the video, the non-RSL riser is blown (after the jumper lets go of it) clear of the deploying reserve PC and freebag since it has no load on it. The RSL riser, bearing the load of the bagged canopy, is naturally going to be leading the non-RSL riser, so if both risers are released at close to the same moment, there should be no interference since they are both getting pulled from the same single point. You're implying in another post that maybe the main PC should be certified since it is the only part of the system that can be counted on to do any actual dragging. What about having everything between the PC and the MARD interlock being certificated? So now the main bag, main canopy, risers, cutaway system, and riser covers need to be certificated in order to use a MARD, or maybe ANY RSL for that matter? This seems to be the path you're going down. While we're going that way, we should require that any certificated system have a method to prevent a reserve from being deployed into a main that has not been fully cutaway, so we're looking at something along the lines of the LOR-2 with an SOS deployment. I don't believe a Racer style cross connector would be sufficient since I think a left side riser release with a replacement ripcord that is too short could create a situation where the reserve pins could get dislodged. I was at the PIA meeting where requiring ceritfication of the main cutaway system was brought up, and it was universally agreed that we didn't want to go there. I don't remember you being there?