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JohnSherman

Do MARD Components require TSO Certification?

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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?



Sure it does! That is one of the reasons we use a Cross connector; To maintaine the integrity of the drag. That's the big problem with single sided RSLs, they don't always produce enough drag. That is also why we reccommend a hand deploy pilot chute be packed into the bag of a direct bagged main on a student rig.
To not use a cross connector is to forfit any drag you might have had within the malfunctined main. Additionall it controles the flailing of the off side riser which could cover the pilot chute from the air stream. Additionally, we found it to be useful in pulling the ripcord.

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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.



Tested to what standard? Do you or anyone else for that matter know the effective size or drag capability of their reserve pilot chute? Just because it passed a couple of drop tests with a selected reserve in a selected container doesn't mean it will do the job with an overstuffed container. What happns when the rig gets into the field and someone over stuffs it. The extraction force goes up beyond the capability of the pilot chute and you get failures at 750 ft when the AAD fires. See USPA Skydiver Advisory 3/10/10
Compatability is the issue. We must have maximinum allowable extraction force for every container and drag capability of every pilot chute to provide the rigger with mixing and matching guidelines. This is why the MARD is conceptually flawed. A maled main has zero drag, a collapsed pilot chute has zero drag. The reserve pilot chute has an unknown drag and the bag extraction force is unknown. And people think this is a well designed system!

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A maled main has zero drag, a collapsed pilot chute has zero drag.



really?

And you keep saying "maled main" what kind af mal are you refering to? Besides the exception of a bag lock possibly, what mal do you think has less drag than a RPC??

Ignore agian I am sure haha.

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***That is also why we reccommend a hand deploy pilot chute be packed into the bag of a direct bagged main on a student rig.

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Can you explain this?

When we first developed the RSL for the Racer it wes tested by two separate outfits. One used a tri-conical and taped the long fold at both ends and in the middle. They direct baged it and it would not pull the ripcord with the cross connector RSL. The other outfit did the same thing with a 28' C9. It worked. Remember neither had a pilot chute but based upon the tri-conical faiure we reccommend to all direct bag static line users a hand deploy and bridle be attached to the top of the canopy as a drag back up in case of streamer.

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I have been asked, by several folks, as this thread has progressed, how can you test a pilot chute?
Well we did it a number of years ago. I searched for the tapes all weekend and just got them digitized and uploaded. It is a boaring 8 minutes but your comments as to the occilations will be interesting.
Enjoy:
http://www.youtube.com/watch?v=Zva4gHVX_zI

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I have been asked, by several folks, as this thread has progressed, how can you test a pilot chute?
Well we did it a number of years ago. I searched for the tapes all weekend and just got them digitized and uploaded. It is a boaring 8 minutes but your comments as to the occilations will be interesting.
Enjoy:
http://www.youtube.com/watch?v=Zva4gHVX_zI



Thanks for posting the video.

I thought many other mfg PCs were tested, please confirm.

Was the area of the PCs measured while inflated?

How much variation in drag force was observed due to the high frequency oscillations?
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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Thanks for posting the video.

I thought many other mfg PCs were tested, please confirm.

Was the area of the PCs measured while inflated?

How much variation in drag force was observed due to the high frequency oscillations?



I am glad you enjoyed it. That makes the effort worth it. Thanks!

The only pilot chutes tested are the ones shown. I believe Manley Butler did some testing but I have never seen anything published. I don’t believe that any other pilot chutes in the industry have been tested. THEY ALL MUST BE!

The area of the pilot chute is what the manufacturer claims. Except for the V2, which we had to measure at the largest point. However, the physical measurement is of no significance as we only measured drag force and "Q" in the tunnel. If you divide drag by the "Q" you get "Effective size" which is what matters when evaluating. Effective size = Cd*So

As to the variations, or the low side during dumping, that data is in an old fashion fanfold computer print out 1 inch thick. I still have it and sometime when I go to the shop (probably after the holidays) I will take a look for you. However, I don't see the need except for academic curiosity. What matters is the high side as that kind of oscillation will only occur when the device is tethered or very heavily loaded while being towed as a drogue.

Nancy once tried a 24 inch Racer hand deploy for tandem drogue. Someday I will post that video (when I find it). It threw both Nancy and her passenger all over the sky. It is funny to watch as the pilot chute seems to remain stable but the tandem pair are oscillating violently below the pilot chute.

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To not use a cross connector is to forfit any drag you might have had within the malfunctined main. Additionall it controles the flailing of the off side riser which could cover the pilot chute from the air stream.



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?

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Tested to what standard?



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?

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Just because it passed a couple of drop tests with a selected reserve in a selected container doesn't mean it will do the job with an overstuffed container. What happns when the rig gets into the field and someone over stuffs it. The extraction force goes up beyond the capability of the pilot chute and you get failures at 750 ft when the AAD fires. See USPA Skydiver Advisory 3/10/10



I think you said it best a couple pages back John:
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I can't fix stupid.



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Compatability is the issue.



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? ;)

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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?



Ever see a jumper on his back with a mal over his head, he is looking up at it, not releasing he is on his back. That’s a zero drag mal. Now release one riser. Of course a riser won't block a pilot chute. But it is a weight with some drag surface at the end of 10 feet of lines which are attached to about 6-8 feet of flopping flailing fabric which could easily overcome the pilot chute and it's bridle.

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Just because it passed a couple of drop tests with a selected reserve in a selected container doesn't mean it will do the job with an overstuffed container. What happns when the rig gets into the field and someone over stuffs it. The extraction force goes up beyond the capability of the pilot chute and you get failures at 750 ft when the AAD fires. See USPA Skydiver Advisory 3/10/10
________________________________________

I think you said it best a couple pages back John:
________________________________________ Quote ________________________________________
I can't fix stupid.



I am not sure whether you are calling me stupid or those unconscious people who died when their AAD fired at 750 feet and their reserve failed to deploy. Or maybe you are calling the rigger who pack said rigs stupid. I agree that sometimes you gotta just shake your head but you shouldn’t just walk away. You gotta try.

Yes, it is a lousy Standard and unfortunately the only thing we have. Better it than nothing. It is absurd to have a pilot chute standard that doesn't include measuring the drag but that is what we have and I for one have been campaigning to change it among other things. Have you been helping?

While I do recommend transitioning from flat to head high during deployment. I don't believe that is what you are referring to. In my paper I recommend testing using this position, only as a compromise suitable to every rig, to measure extraction force by the inspecting rigger. I figure we can't ask a rigger to do this more than twice during an inspection cycle. If you like a different direction, say so. I could handle straight up at 90 degrees.

I agree completely that such a scenario of giving up and assuming a flat and stable with a big burble is possible. But what does that say about our teaching if it is true. However, none of the incidents referred to in the advisory, that I have examined, have shown this to be the case. There are videos of high bag extraction force all over the web and more stories from riggers. Yet none of the manufacturers have made an effort to identify, and limit extraction forces or, pilot chute drag capability. By comparing the two numbers we have mathematical proof of function and guidelines for riggers.

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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.



Kelly,
I agree whit what you are saying. However if the main fail to extract the freebag, reserve PC will probably be facing upside down for the first stage of the deployment. Eventually will take over and finish the deployment, but is it going to be in the 3 second or 300 ft?! Maybe, or maybe not. We don't know. It wasn't tested that way.

As for the .5 % failure of the Skyhook, I don't think it's real. I've seen it fail twice. And I haven't witnessed 1000 reserve rides. But we have to be realists. Do you think they can sell 15 000 Skyhooks if they are giving the real data :S
"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

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Holy occilations batman!

That youtube clip of the Vector 2 reserve pilot-chute just screams out for the addition of equatorial vents (ala. AT-11, Sigma drogue and Strong Tandem drogue), but I guess that - given the short exposure, oscilations are a minor hassle with reserve pilot-chutes..

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"Ever see a jumper on his back with a mal over his head, he is looking up at it, not releasing he is on his back. That’s a zero drag mal."

Can you explain how that is zero drag? Wouldn't drag be one of the reasons he is on his back during the mal?

Matt
An Instructors first concern is student safety.
So, start being safe, first!!!

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Yes, it is a lousy Standard and unfortunately the only thing we have. Better it than nothing. It is absurd to have a pilot chute standard that doesn't include measuring the drag but that is what we have and I for one have been campaigning to change it among other things. Have you been helping?



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 :D

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While I do recommend transitioning from flat to head high during deployment. I don't believe that is what you are referring to. In my paper I recommend testing using this position, only as a compromise suitable to every rig, to measure extraction force by the inspecting rigger. I figure we can't ask a rigger to do this more than twice during an inspection cycle. If you like a different direction, say so. I could handle straight up at 90 degrees.

I agree completely that such a scenario of giving up and assuming a flat and stable with a big burble is possible. But what does that say about our teaching if it is true. However, none of the incidents referred to in the advisory, that I have examined, have shown this to be the case. There are videos of high bag extraction force all over the web and more stories from riggers. Yet none of the manufacturers have made an effort to identify, and limit extraction forces or, pilot chute drag capability. By comparing the two numbers we have mathematical proof of function and guidelines for riggers.



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.

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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.



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.
OH BTW: It was nice to have the Ames Wind Tunnel time but it is not necessary to do the job. I can and have used 2 other methods. One for developing the Cd for our tandem drogue. (.12)

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Can you explain how that is zero drag? Wouldn't drag be one of the reasons he is on his back during the mal?



The first event in an opening sequence is "Snatch" which technically means "Accelerating the mass to speed". This sits you up into a vertical position. The next phase is "Plate Inflation". A high speed mal might not achieve this state. Snatch turns into a streamer.
Your speed increases and both you and you passanger (if you have one) begin to have your feet float up and you find yourself on you back. Most of the time you don't realize it as you are looking up at the canopy. But note your neck angle is less. You are now effectively back in free fall on your back. Your malfuncrioned main is generating no drag. Remember Vasili in Guam. Look at his pictures.

Let me expand upon the phrase "No Drag" I find it analogous to No Gravity. Astronautes will tell you there is no such thing as no gravity. They call it "Micro Gravity". So when I speak of No drag I mean Micro Drag, as technically, unless it is not decending there is some drag.

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OK, I "see" what your describing now. I misunderstood and thought the jumper was on his back and looking above him relative to his body (horizontally in this case) not above him in relation to the earth.

Matt
An Instructors first concern is student safety.
So, start being safe, first!!!

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What speeds were you testing the pilot chutes to? I ask because we blew up a lot on a project where we had them attached to the top of a 16 foot slider reefed canopy. We were a little fast about 300 ft per sec or so they told me. but with it towing behind the small canopy rather then just slipping the free bag off we consestantly blew then to hell. Torn mesh, blown out fabric, broken tapes, bent springs. In the end we had to build some heavy ones of our own. We started with RI pilot chutes, both the cilindrical and stelth. Blew them all up and then moved on to your small reserve pilot chutes and blew them up. Your mini racer spring was just the perfect diamiter for the final tube size.

To every one else. This was kind of an extreame situation. And even then when they litteraly disintergrated they still did there job. And nancy was very helpfull sending us those springs when we were in a jam so I'm not dissing them. I'm just curious cus it really surprised me when I blew the first one up.

And by the way that's not ossilation. If you want to see ossilation I'll see if they'll let me post a link to the latest vid. We had a slight flutter problem on our last flight when the drouge was supersonic. You can watch my latest ceation drop another half million worth of equipment into the ground. I think it was the trans sonic range that really tore it apart.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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What speeds were you testing the pilot chutes to? I ask because we blew up a lot on a project where we had them attached to the top of a 16 foot slider reefed canopy. We were a little fast about 300 ft per sec or so they told me.



We tested to a max of 33PSF (Q) which occurs at terminal for a Freefaller (120MPH+/- @2000'). At 300 FPS your Q is in the neighborhood of 100+ pounds per sq. Ft. No wonder you were blowing everything up.
See: http://www.jumpshack.com/Q.htm for the value of "Q" Pounds per sq. ft. The speed in FPS, Knots & MPH are across the top and altitude is the "Y" axis.
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And by the way that's not ossilation. If you want to see ossilation I'll see if they'll let me post a link to the latest vid.


I'll bet the video is blured I would imagine the amplitude is not any more but the frequency must be off the chart.
In the test at Ames we tested refueling drogues to 200Q so I am aware of what you experienced. I have video from Ames with drogues at 200Q stable as a rock. I may post them for your entertainment, that is as soon as I get them all digitized.

John

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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.



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.

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If you don't have to test the container, how do you know if it has acceptable extraction forces?


Of course you have to test the container. I will go farther and say that if you arn't designing your containers to to provide for a maximinum extraction force based on your pilot chute you arn't doing you job.
When I started I only had the MA-1 but I knew what it drug and when I went to the free bag I set limits on extraction. Any designer who hasen't done that should take up setting pins at the bowling alley we send turkeys to. Sorry 'bout that but there is more to this business than looking good!>:(

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If you don't have to test the container, how do you know if it has acceptable extraction forces?


Of course you have to test the container.



Then why did you say in post #91:

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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.


People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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Then why did you say in post #91:

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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.



I said it because the manufacturer really doesn't have to test the container. But he must design it to not require an extraction force greater than the pilot chute drag. That to me seems intuitive.
The assembling/repacking/inspecting rigger is the one who must measure and certify the extraction force is not greater than the manufacturer allows. The same as he must certify the ripcord pull force doesn't exceed the standard. Please read:http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Extraction_of_Rsv.&SortBy=DATE_D

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The assembling/repacking/inspecting rigger is the one who must measure and certify the extraction force is not greater than the manufacturer allows.



John,
This is where I totally disagree with you!

First there is no FAA approved standard or requirement for field riggers to do this.

Second, there is not an approved testing measure in the PTS to assure riggers are competent to do this.

Third, the regulations state that the rigger shall have enough knowledge, skills, and equipment to do the work at hand.

We are one of the largest rigging lofts out there in the field and we do not do this, nor have the equipment set up for this, nor any training to assure proper test results.

With that said, do you actually think smaller lofts and riggers working out of their car trunks do this? The answer is a big "NO"...

Fourth, it is the manufacturer's responsibility to determine what works with what in the aviation world.
ANY aircraft part has an application list as to what it will fit, works with and is certified for.

Parachutes and their manufacturers ARE in the aviation world. They are also governed by the same agency and share certain regulations which I believe differ from your and most other manufacturer's opinion on this matter.

Cheers,
MEL
Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

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