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JohnSherman

Do MARD Components require TSO Certification?

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If you care to comment on any of my posts and want my response you should identify yourself and fill in your profile.
I don't respond to people who hide their idenity and experience.
How can one craft an answer if one doesn't know the intelectual level of the person for whom you are crafting the answer.

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If you care to comment on any of my posts and want my response you should identify yourself and fill in your profile.
I don't respond to people who hide their identity and experience.
How can one craft an answer if one doesn't know the intellectual level of the person for whom you are crafting the answer?



I have the same questions, and my profile is filled in. :)
Mark

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If you care to comment on any of my posts and want my response you should identify yourself and fill in your profile.
I don't respond to people who hide their idenity and experience.
How can one craft an answer if one doesn't know the intelectual level of the person for whom you are crafting the answer.



weak.

one's intelligence level is not a field we get to fill out in our dz.com profile, and having 10,000 skydives does not make one a genius.

Let my semi-anonymous person ask you a much more basic question - why does JumpShack not put DOM on their gear ?
I know the manual states "The first two dig its of the se rial number de note the week of manufacture. The third digit denotes the year. The last two dig its de note the sequence"
Surely having gear that goes back 30+ years and having lived through the Y2K scare you realize that having a single digit year identifier is inefficient ?

Would love to hear your answer to this. If not, I would love to hear you justify how my semi-unfilled profile makes you unable to cater an answer to my (un)intelligence level.

thank you

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Well you would not be replying to me, you would be replying to someone who has "identified" himself.

You clearly are deflecting, which is odd because I was actually just interested in your response, now I can see why.....

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MARDs preempt the function of the reserve pilot chute and should be Certified as the reserve pilot chute.
I believe that their current use is a violation of the doctrine of “must not interfere with the normal function of…”

The main pilot chute is the only part of a MARD which is doing the work of dragging.


I'm only going to reply to these statements, and try not to get too wrapped up in this discussion.

John, MARD's DO NOT preempt the function of the reserve pilot chute, they simply assist it. If any part of the main parachute assembly fails to provide enough drag to extract the reserve canopy from the container, or bag from the canopy, the reserve PC is still there to finish the deployment as originally designed. You can see this happen in the video that Jerry posted during the baglock test. The main initiates the deployment, but the reserve PC finishes it. It's also interesting to note that the RAX interlock does not disconnect in this scenario like the Skyhook does in the UPT video- there is no need in this situation.

I do agree with you that SOME MARD's can interfere with the normal function of the reserve PC in some low speed scenarios, which is one of the reasons you don't see us selling Infinitys with any MARD's currently available to the sport market.

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Ok Mark Here is the answer:
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If I remember correctly. I see a complete reserve deployment in just about the same time as a skyhook assisted reserve deployment following a cutaway (approximately 2 seconds).

So far so good, but…

1.
Test jumper is pulling both handles at the same time. I use the two hands on each handle technique and would not be able beet any RSL or MARD for that reason alone.



The test jumper is pulling only the cutaway and he is doing it with both hands. The reserve ripcord is not touched. This is strictly an RSL deployment. Slo-Mo it and you will see the cross connector pulling the ripcord.
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2. It takes the freebag 1.5 seconds to reach line stretch. The same as just about every other container on the marked that I know of (I’m a newbie rigger and I haven’t seen a whole of different rigs).
The skyhook accomplish the same in 0.5 seconds. How is this not faster?



By my count line stretch occurs at about 1 second which makes more sence acording to the physics of acceleration. The canopy takes about 1 second to inflate. The only way to improve this distance is to shorten the reserve free bag bridle. I could knock of some 15 feet of deployment distance with a short bridle. That's what a MARD does, it grabs the reserve bridle at about the half way point shorteniong it.

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3. The reserve inflation in your video is about 0.5 seconds. Every other reserve inflation I have seen on tape is about 1.5 seconds. (again, I’m a newbie rigger and I haven’t seen a whole lot of them either).
I can’t help but wonder if the reserve inflation in your video could be lethal if deployed at terminal velocity?



Send me you address and I will send you a canopy to try. To understand our deployment capability read the curent review on the FireBolt. It's the same technology.
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The way I see it, the Racer is no faster than any other container. The reserve in your video however is a lot faster. How can any container speed up a reserve inflation?



For 30 years we have been deploying reserves that fast. For 30 years people have denied that it was possible. Now there are MARDs and they have shown that reserves can in fact be deployed in 2 seconds. But at what cost?
If you take all the videos from the Jump Shack web site and do the same for the MASD makers web site and edit them to side by side starting evenly at the cutaway you won't see a significant difference. I win one they win one. Mine is Certified and correctly TSOed. Sorry 'bout my web site they are working on it, I hope

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Kelly,
When you jerk the free bag from the container by the mid -point of the bridle using a non-certified device you are "interfering with the normal operation of" and that device should be Certified. I watched your video, your reserve pilot chute is upside down during the extraction of the bridle and bag. Thats not assisting its prempting. Granted your pilot chute doesn't stay inverted very long but if you still have a flailing riser, the posibility of a low drag mal and a collapsable pilot chute that reserve pilot chute better take over.

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Thank you for your reply, even though it was not directed at me (the original poster).
I think it’s pretty amazing that one of the major designers in this sport takes his time to answer my questions.

I have now filled in some info in my profile and hope I will be deemed worthy of a reply. You may safely assume a low intellectual and experience level in your response. ;)

I found a copy of the video on youtube.com http://www.youtube.com/watch?v=il735eAFyw8 maybe we’re talking about different videos?

I made the weak assumption of pulling both handles at the same time based on the orientation of the test jumper arms immediately after cutaway (screen1.jpg). My bad, I’ll give you that one.

However I still disagree with your timeing. I have attached some pictures of your video with your embedded stopwatch. I trust it to be correct.

At 0.5+ seconds (screen2.jpg) the RPC has reached full bridle length but freebag is still inside container. I don’t understand how you can claim that your system is just as fast as one with a MARD. If you had a skyhook the freebag would have been at line stretch at this point (if it worked perfectly). How is that not faster?
We all know the skyhook does not work perfectly every time, but I think Bill Booth claimed over 90% in one of the PIA videos. I have no idea if the number of test jumps even come close to be considered statistically significant to claim such a success rate, but I can’t prove it to be false either.

At 1.4+ seconds (screen3.jpg) the freebag has reached line stretch. This is about average (as far as I know). At 2.0 seconds you have a fully inflated reserve. 0.6 second reserve inflation is too fast for my taste. I can’t comment on the physics of acceleration or the consequence’s of shortening the bridle length, but I can watch your video and its embedded stopwatch and tell that line stretch is at 1.4+ seconds.

“Now there are MARDs and they have shown that reserves can in fact be deployed in 2 seconds. But at what cost?”

Now this is a valid argument, and that cost has proven to be substantial in more than one incident, but claiming as fast reserve deployment as a MARD is not. (at least your video does not prove it)

A skyhook assisted reserve deployment achieves a 2 second reserve deployment by shortening the time is takes to reach line stretch by 1 second. You achieve the same by shortening the reserve inflation by 1 second. But at what cost?

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"0.6 second reserve inflation is too fast for my taste."

Let's see you say that with a reason to cutaway at 600 feet ;)

Unless it causes physical damage to your body I don't think it could be fast enough. I've had a terminal Racer deployment (at 4,500 feet) and my inner thighs were sore for a day or so but I'd never ask my rigger (myself) to try and slow down my deployment speed. Search YouTube for low cutaway videos. Some are caused by pilot error, some by environmental factors, but I would bet you that every person that had to cutaway the last thing on their mind was "wow that opened hard." Their thought process is probably more like "thank god that opened!!" They may complain a little later about being sore but the point is they ARE there to complain. :)
Just so you know, I am currently employed by PLI, but have been a fan of the Racer since I started jumping. (I've had 3 now and am about to order my 4th):P

I am in agreement with John that this needs to be addressed and should be soon. Most people have failed to understand that without a MARD system, John has achieved a 2 second reserve deployment with the Racer. No other container that I know of can claim that. The only way he sees making this process faster is by shortening the reserve bridle. HMMM that's what the MARD does, but we do not have to have the main attached to the Reserve bridle in any way. I have always believed in the KISS principle and that is why I love the Racer because John has not engineered it to death trying to make it par with the rest of the industry. It had set the standard that everyone had to strive to achieve. The challenge has been met but at what cost?
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You are missing my point. I too want the reserve to open as fast as possible, but not to the point where it could kill me. Sore inner thighs is normal for any reserve deployment at terminal. It does not mean your Racer was super fast.

My original question was how the Racer or any other container for that matter can influence the speed of the reserve inflation. Because this is where the video is faster. It is no faster than any other container on the marked (that I know of) in bringing the freebag to line stretch. This is where the skyhook is faster.

He may be able to claim the fastest reserve inflation on the marked, but the Racer has nothing to do with it unless I’m missing something, hence my question about how it can influence the speed of the reserve inflation. If the reserve inflation in the video is safe and normal, then I want it in my new V3 with a skyhook and have a complete reserve deployment in 1 second.

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:)
***

With so many MARD's out and about with millions of jumps and yet none having caused any fatalities or hindering any deployments

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You may want to check on that statement.



Please me more specific on that.

Thanks.



http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=3331658;page=8;sb=post_latest_reply;so=ASC;mh=25;

http://www.uspa.org/USPAMembers/Safety/AccidentReports/tabid/81/ctl/Detail/mid/785/Default.aspx?xmdata=k2m5MCXrW8e/Oq/1eaYYusJaIdUJ2v9nn3SvbjJUQy1Hb4Faaij4QbSNNNDw1zR%2bzW0vIEPL6aA%3d
----------------------------------------------
You're not as good as you think you are. Seriously.

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He may be able to claim the fastest reserve inflation on the marked, but the Racer has nothing to do with it unless I’m missing something, hence my question about how it can influence the speed of the reserve inflation. If the reserve inflation in the video is safe and normal, then I want it in my new V3 with a skyhook and have a complete reserve deployment in 1 second.



Good argument. Also, Jumpshack claimed the 64-foot reserve deployment (complete) in their ads. Please read from the linked post, down:

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=790802#790802

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Lars,

Now that we have been formally introduced I feel I can speak to you directly. I wasn't trying to bust your chops but I feel that in a Forum such as Gear & Rigging there should be no hidden identities. I do know some manufacturers do do that. They have admitted it to me. I believe in the light of day.

The fact that we can deploy a reserve in 2 seconds and a Tandem in 4 seconds is a long established fact.

We do it by honing all of the components to their maximum performance. For example the Drag coefficient for the reserve pilot chute is .84. It's the highest Cd for any pilot chute anywhere. It was tested by NASA at NASA Ames. (BTW: All reserve pilot chutes should be tested and placarded with their capability). The extraction effort of our container plays a part. It is limited to 110% of the weight of the bag and canopy. My published data calls for a max of 16 pounds, this is because of heavy tandem canopies.

We are looking at different videos. That is why we are getting a .5 second differential. I was quoting the deployment on the Jump Shack home page. I believe the difference of what you got and what I got is about .5 seconds and is not germane. It is academic.. They both occur in about 2 seconds. I would like to link you to more videos on my site but it is producing errors and I can’t send you the file as it is too big for DZ.Com. Send me your outside E-mail and I will send you some interesting stuff or you can wait until the site is fixed.

If there was a cost to the Racer reserve deploying in 2 seconds it has never come to light. We have been deploying reserves in 2 seconds for 30 years. They used to say it wasn't possible. BTW: It takes about the same time for a terminal opening. The distance increases because you are going faster. But now they can't deny it because the MARDs can do it.
The Mard does it by shortening the bridle. If I shorten my bridle to say 5 feet I could cut off some distance from the 97 feet it now takes, Footage, I hope will be forth coming. I have prepared the bag and it is packed. I don't think it will ever be released as I do like the long bridle, but it will be a neat demonstration.

Now, to the meat of your question. How do we make canopies inflate faster? Try this. The dynamics of the drag of the pilot chute is such that it creates a tension between the high dragging pilot chute and the bag. I believe it actually stretches the bridle during line deployment. The tension is extended through the bag and into the canopy lines which accelerate the canopy out of the bag into a more rapid inflation. Failing that theory I don’t have a clue, but it does it and it has done it for 30 years, and that is what is important.

John

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If I shorten my bridle to say 5 feet I could cut off some distance from the 97 feet it now takes, Footage, I hope will be forth coming. I have prepared the bag and it is packed. I don't think it will ever be released as I do like the long bridle, but it will be a neat demonstration.



I know you said you probably wouldn't release it, but how would a 5' bridle work in a burble? I thought the longer bridles were so the PC could clear the burble and catch some cleaner air?
"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
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I thought the longer bridles were so the PC could clear the burble and catch some cleaner air?



I believe the reserve bridle has to be longer that reserve parachute lines, so that in the event of a horseshoe it will allow the line stretch on the reserve lines, while the reserve PC is entangled with your leg for instance.

As discussed before, the bridle alone does not generate enough drag to lift the reserve bag, but you can help it by pulling on the bridle itself, starting the freebag movement and having it created its own drag.

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Do the component which make up a Main Assisted Reserve Deployment system require Certification under the TSO system?

Have Fun! :)



Sky Jumpers I would not EVER debate with:
Bill Booth
John Sherman
Ted Strong(RIP)
Nancy LaRiviere
Paul Poppenhager
Bob Bowen
Mike Furry
Ralph Hatfield
( Please feel free to make additions)B|

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Kelly,
When you jerk the free bag from the container by the mid -point of the bridle using a non-certified device you are "interfering with the normal operation of" and that device should be Certified. I watched your video, your reserve pilot chute is upside down during the extraction of the bridle and bag. Thats not assisting its prempting. Granted your pilot chute doesn't stay inverted very long but if you still have a flailing riser, the posibility of a low drag mal and a collapsable pilot chute that reserve pilot chute better take over.



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?

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There has not been an Infinity rig built with a MARD at this point.



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.


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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.



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.


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Your notion of having a "flailing riser" doesn't make a whole lot of sense to me,



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?

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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.



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.

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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?



I may or may not have been to the specific one to which you refer but I have been to a few where it was discussed. I agree about not going there and have not proposed it.

I believe we have minimum regulation s for a reason. To protect the public is the job of the TSO. If products are released without consideration of TSO requirement and consultation with the FAA the manufacturer is being irresponsible. The lust of the almighty buck has got them by the balls. I am a capitalist to the core but unbridled capitalism is as evil as unbridled comuninism. Corporations large and small must play by the rules. I would be pleased to know if any of the current MARD producers have ever contacted the FAA about this question.

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There has not been an Infinity rig built with a MARD at this point.



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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.



So your theory is that people shouldn't develop better systems(whether or not they are different) than which the pilot chute could perform at/ever extract the reserve? Sure its no longer just a PC but its better. The market and the skydivers seem to agree as well since other manufacters have implemented it to their rigs as well. It's like saying using magnetic riser covers are for the rigs that have shitty riser covers...its called improvement whether or not its the same device it essentially does the same job intended...but better in the manner that it was developed for.



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I believe we have minimum regulation s for a reason. To protect the public is the job of the TSO. If products are released without consideration of TSO requirement and consultation with the FAA the manufacturer is being irresponsible. The lust of the almighty buck has got them by the balls. I am a capitalist to the core but unbridled capitalism is as evil as unbridled comuninism. Corporations large and small must play by the rules. I would be pleased to know if any of the current MARD producers have ever contacted the FAA about this question.



Oh consulting with the FAA huh? Did you mean this guy by any chance? http://news.yahoo.com/faa-chief-charged-drunk-driving-police-192752609.html ;)
For info regarding lift ticket prices all around the world check out
http://www.jumpticketprices.com/dropzones.asp

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I believe we have minimum regulation s for a reason. To protect the public is the job of the TSO. If products are released without consideration of TSO requirement and consultation with the FAA the manufacturer is being irresponsible. The lust of the almighty buck has got them by the balls. I am a capitalist to the core but unbridled capitalism is as evil as unbridled comuninism. Corporations large and small must play by the rules. I would be pleased to know if any of the current MARD producers have ever contacted the FAA about this question.



Manufacturers of BASE gear seem to be doing a fine job of regulating themselves.

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