Is a Cobalt safer for big way jumps?

[flyhi 24]

The November 2002 Skydiving newspaper said that investigators believe the death at the JFTC resulted from an extremely hard opening, which may have been caused by dumping in a track.

I wonder if Cobalt's two stage deployment doesn't offer two levels of safety on bigways. First, it would allow you to maximize your track and get further away from everyone else, and second it would not penalize you with a hard opening at the end. Granted these benefits would be just as applicable on any jump, but would prove much more critical on a big-way.

I neither own nor jump a Cobalt at this time, but along with their other design features, I will probably take this safety aspect into consideration the next time I do buy a canopy. Any thoughts?

Shit happens. And it usually happens because of physics.

[PhreeZone 15]

Any canopy can open hard... Cobalts included. If it was something likea hard opening from deploying in a track, no canopy is really safer then another. On bigways its not the time to be jumping your VX50 and having to weave in an out of traffic since you are crusing at twice the speed as others. The canopy of choice at out DZ for the people that are doing big ways are the Spectre, Sabre2 and larger Stilettos.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[cloud9 0]

You know as I read my skydiving magazine, I pondered the same question. While I do believe that any canopy can open hard and at this time I don't have enough information to say what caused the hard opening at JFTC. I would think that if its true that cobalts can be opened in a track with no ill effects then it would be a wise choice. I would like to hear from Cobalt owners that have in fact opened in a track and what the results were. If you haven't dumped a cobalt in a track then your opinions are invalid and you just plain don't know. So what about it cobalt owners?

[PhreeZone 15]

As a former (its still mine, just in the closet) Cobalt jumper, I've dumped in a Sit, Stand, Full track, 5 second delay on a Casa jet pass... you name it except for HD. Every once and a while for no real reason I'd have a fast opening. Still not a slam but somewhat fast. Dumping in a full track tended to lead to a staged opening where it would snivel for a while then power the slider down fast. I never had a fast opening on a high speed deploy, but my new canopy opens just as nice in a full track as the Cobalt did. There is more to a canopy then how it opens.

I would'nt want the softest opening canopy on big ways if it was also super zippy. I'd perfer a balence between a docile canopy and everything else.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[cloud9 0]

Hey Phree that's very interesting, what's your new canopy? Your saying it opens just as good (soft) in a sit or track as a cobalt?

I know what you mean on the pocket rockets but that's all after opening. I think that any canopy that can save a life by opening soft even when the speeds are high or less then favorable should be talked about. I know that Atair advertises this but if its true it could really make a world of difference.

I have tried opening a Triathlon, Hornet, Stiletto and Heatwave in a track, not a hard fast track either all of them opened hard. I would hate to get caught low and have to dump in a very fast track. All of the above canopies were loaded at 1.4 or less so no heavy wing loading here! Not a lot of attempts either I know when to quit.
I have never jumped a Cobalt.

[TomAiello 25]

Can anyone provide information on cases where a hard opening has caused injury or knocked a jumper unconscious?

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[Cajones 0]

Definitely. I know of a few cases I've seen, but I have also had one of my own. I was jumping a Sabre 150 (cringe!) that belonged to a friend. I was shooting video two-turn-loads and shut down style. Edit and pack while the plane is shut down, do two more... Sabre smacked me so hard, I was seeing stars. Had to miss 6 weeks of jumping (including a very big boogie), and spend many $$$ at the Chiropractor. By far, the worst injury I've had in skydiving.

The laws of physics are strictly enforced.

[PhreeZone 15]

I'm yet to dump my Jedei in a sit (stupid clouds), but at full track its not that bad of an opening at all. On video I'm typically the first out of frame and I tend to be one of the longer trackers on all the RW stuff I've done so I've still gots lots of forward speed.

Yes, I'm a bit scared to dump the Jedei in a sit, but I'll eventually do it. The Cobalt was actually fun to freak people with by tossing right in front of them in a sit if everything was set up right. After 5 times doing high speed deployments, I got nailed on a normal opening. I was grounded for 3 days due to a brand new, fresh out of the box Cobalt opening so hard you could hear a crack sound on the video while doing flat flying solos so no tracking or anything was involved. It actually make the video get pixelated from the one opening. After 4 jumps on the canopy I had to put it away and jump my old Cobalt. Even Cobalts are capible of nailing you.

Body position and packing can make a lot of difference in canopy openings. Cupping air and hitting the brakes as you toss will help any canopy. It takes all of the wave off to hit the brakes and cup so your not using any more time then normal. Packing methods can cause faster openings on some canopies if you roll the nose while on others it will be softer.

Fast opening canopies can be tamed via larger sliders, pocket sliders, or even nose mods to the canopy.

> All of the above canopies were loaded at 1.4 or less so no heavy wing loading here!
1.4 is advanced levels or above on PD's charts so 1.4 is'nt that light of a loading.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[rgoper 0]

my observations about the Cobalt are the exact same as Phree's. the thing i hate the most is the end cell closure after the second stage opening sequence. packing is essential in each and every canopy, no matter who the manufacturer is. i've been slammed by just about every canopy i've ever owned, and 90% of the time it was my fault for the packing procedure. i still own my Cobalt, i have a new Pisa Heatwave coming that i can't wait to fly, but i will keep my Cobalt, i'll just send it in and have it checked at Atair when the Heatwave comes. but the hardest i've ever been "slammed" on opening, was on a 190 Triathlon, 7 cell square, i guess i didn't quarter the slider or whatever? it slammed me so hard, it sprained my left ankle, and hurt my kneck, i was done jumping that particular day. a camera jumper at our DZ in houston got slammed a while back, and hurt his back, and kneck pretty good, but he's allright now. i hate a "snively" canopy, but i hate a "slammer" as well, would somebody please design a conopy that deploys comfortably from any position, no matter if trash packed, or meticulously packed...PLEASE!

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[Kris 0]

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would somebody please design a conopy that deploys comfortably from any position, no matter if trash packed, or meticulously packed...PLEASE!

Hmmm...sounds a lot like my Stiletto. There are times when I just clear the line-groups from the tail, make sure the slider is against the stops (what's quartering?), and trash it into the d-bag.

The openings are soft and on-heading. The very few times I have had a harder opening I would call them brisk, not hard. I have deployed my Stiletto in a track and in a sit.

My normal deployment speed is around 129-137.

Kris

Sky, Muff Bro, Rodriguez Bro, and
Bastion of Purity and Innocence!™

[crazy 0]

Quote

The November 2002 Skydiving newspaper said that investigators believe the death at the JFTC resulted from an extremely hard opening, which may have been caused by dumping in a track.

I wonder if Cobalt's two stage deployment doesn't offer two levels of safety on bigways.

While i have no doubt that an extremely hard opening can cause serious injury, i am wondering why opening in track would cause hard openings. As long as you don't really know the detail of the hard opening, it's quite difficult to speculate on any solution.

What's wrong with dumping in a track?

bb

--
Come
Skydive Asia

[riggerrob 558]

Calling all POPS!
Now is your turn to wax elloquent about the beautifully soft openings we used to get on Strato-Clouds with bottom skin reefing ropes.
Let's try not to spoil the fun by mentioning how we packed reefing ropes.

[rmsmith 1]

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...would somebody please design a conopy that deploys comfortably from any position, no matter if trash packed, or meticulously packed...PLEASE!

It's called the PD Spectre!

[PhreeZone 15]

Its possible for a hard opening to cause internal damage or just render the jumper unconsious for some time. Being knocked out under a spinning canopy can quickly lead to impact. Lets not go into the results of something like a torn aorta or a ruptured lung while under canopy.

Opeing in a track induces a lot more velocity into the mix. Force is'nt scaled linear, its a progressive curve. I'm not sure of the exact figures but if even 5 mph faster results in a 1% harder opening, then a 7 mph could be 3%. Figure in that you are able to track at 35-50 mph away from a formation that could be a lot harder opening then you want. Hitting the brakes right before you dump will lower your speed and decrease the opening force that is applies to your body. Materials like Dacron can also help in this type of issue.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[TomAiello 25]

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Opening in a track induces a lot more velocity into the mix. Force is'nt scaled linear, its a progressive curve. I'm not sure of the exact figures but if even 5 mph faster results in a 1% harder opening, then a 7 mph could be 3%. Figure in that you are able to track at 35-50 mph away from a formation that could be a lot harder opening then you want. Hitting the brakes right before you dump will lower your speed and decrease the opening force that is applies to your body. Materials like Dacron can also help in this type of issue.

I dump directly from a track on pretty much every terminal jump I make. I'm using a freepacked canopy with a mesh slider, pretty much packed for fast openings.

What I'm trying to figure out is how I can do this consistently, and skydivers are getting injured doing it. I would speculate that the line material is the major factor, since the rest of my opening ought to be occuring faster (hence probably harder) than a skydiving opening.

Does anyone have any thoughts on this?

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[quade 3]

Generally speaking for big-ways you'd want a fairly docile canopy that you can pack without worring about it too much and -not- rocket through the landing area. Swooping -through- 100 or more people is freekin' dangerous -- far MORE dangerous that any chance of a snappy opening.

A Spectre loaded to manufacterer's recommendations would be a good choice. Generally speaking you can quickly pack a Spectre and not worry too much about it -- it really wants to open on-heading and softly pretty much no matter what you do to it. I have about 1200 jumps on Spectres, no hard openings and ZERO cutaways. They're -VERY- reliable. Loaded at about 1.3:1, they even drive forward pretty well and can get me back from -almost- any bad spot (Ok,l I have landed out -once-). Of course, I'm also jumping camera and opening about 1,000 feet higher than everbody else, but still . . . .

Boring? Yeah, exactly what is called for.

quade -
The World's Most Boring Skydiver

[PhreeZone 15]

I'm a bit confused at the mesh slider at terminal, I always thought it was sail sliders on 10 second delays...

I think a lot has to due with your fall rate too, BASE jumpers are usually known for thier ability to go slow, where as skydivers tend to have bad tracking abilities.

I think a lot has to due with canopy design too. There is a reason that mesh sliders are'nt on skydiving canopies. Base canoies can handle repeated terminal openings in less distance then skydiving canopies do.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[quade 3]

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Opeing in a track induces a lot more velocity into the mix.

Probably a lot less than you're assuming.

I'll keep the math here simple and unrealistic so that this makes sense but you'll get the idea.

If you had a perfect 1:1 glide ratio in a track (traveling forward 1,000 feet for every 1,000 foot downward) and got your vertical rate of decent down to 100 mph, then your total velocity would only be about 141 mph.

I'll admit that this is an increase from a nominal vertical decent rate of 120 mph just falling straight down, but as you can see, it doesn't really increase the total speed all that much.

Ok, so what does this do to the forces?

141 / 120 = 1.175
1.175^2 = 1.380625

So, The opening forces at 141 are going to be about 1.38 times the forces of the opening at 120 mph IF (and this is a big if) the opening takes place in the same amount of time and distance (which it probably won't -- it'll probably be a bit slower and further).

quade -
The World's Most Boring Skydiver

[TomAiello 25]

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I'm a bit confused at the mesh slider at terminal, I always thought it was sail sliders on 10 second delays.

That's a pretty serious misconception. Modern BASE jumpers virtually all use mesh sliders exclusively. There are very few experienced modern BASE jumpers who use sail sliders for BASE, even at terminal (I think I can count them on one hand). One of them is a major gear manufacturer, however, so many beginners take his advice, and start out with a sail slider, then stop using it after their first big wall trip, when they realize that there is a reason no one else uses them. Also, at least one fatality this year may have been contributed to by the use of a sail slider (hence losing us one of those less than five sail slider jumpers). Sail sliders tend to create inconsistent openings, often compromising heading or creating weird snivels.

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I think a lot has to due with your fall rate too, BASE jumpers are usually known for their ability to go slow, where as skydivers tend to have bad tracking abilities.

I have a reputation in the BASE world for tracking like a brick anvil (actually, I believe the phrase I hear most often is "tracking like a goat--an athletic goat--but still a goat"). I don't think that's going to be the answer.

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I think a lot has to due with canopy design too. There is a reason that mesh sliders aren't on skydiving canopies. Base canopies can handle repeated terminal openings in less distance then skydiving canopies do.

The canopy is built to handle those openings, sure. But what about the human body underneath it? I know that my Blackjack (bottom skin inlets, ZP topskin) opens way harder than my Stiletto.

I'm wondering if the BASE canopies are so much more consistent that they eliminate the very top part of the curve (where the openings are so hard as to be injurious). Perhaps BASE jumpers expect a harder opening, so they are braced for it? Maybe skydivers expecting a softer opening get taken by surprise when they get slammed?

I don't really have any good ideas on this. I just know that I've never heard of a BASE jumper being seriously injured by a hard opening. Sore necks, sure. Back pain, sure. Seeing stars, very occasionally. But knocked unconscious? I don't know.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[crazy 0]

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Opeing in a track induces a lot more velocity into the mix.

Do you have any data to backup this claim?
The vertical speed of a belly flyer at 2500 feet is around 125mph.
The vertical speed of most good trackers will be close to 75mph at 2500 feet (this is easy to check, ask a good tracker what is his lowest average speed on the protrack). As long as his horizontal speed is lower than 100mph, the velocity of the tracker is lower than the velocity of the belly flyer (75*75 + 100*100 = 125*125).

Do you have any evidence that a tracker can go faster than 100mph horizontally?
My personal experience shows much less than this. Experience done with a pro-track set at 7000 and 3000 feet. I spotted at both altitudes and measured the distance. I admit, it's very inaccurate, but it was much less than 1 mile. More like 4000 feet.
I got the same kind of measurement from 2 other people. One guy once claimed he got a glide ratio of 1.2, but he never gave me all the data. If you are a good tracker, make the experiment yourself to be really convinced. If you're not that good, pay a beer to a tracker nearby to organize more track jumps .
BTW, I've dumped in track hundreds of time at wingloadings from 1.4 to 2.5 (never tried with a cobalt, an air-locked or a x-braced). Always had very soft openings.

bb

--
Come
Skydive Asia

[ltdiver 3]

Yes, well, what if the tracker was doing something a bit more (or alot more) steep than the most horizontal and perfect track? I've seen, as I'm sure you have as well, trackers that do more of a dive strategy.
What would -that- do to the forces? Mathmatically.

Additionally, I've personally seen a Stiletto-135 that was ripped clean in two after a cameraman opened (after filming a tandem). DZ elevation was sea level. Slider was correctly unstowed. He always rolls the nose when packing. Wing loading 1.37:1.

The opening was so hard that it nearly knocked my friend completely out. Luckily it didn't and he was able to successfully land his reserve. His jump numbers? Over 10,000. He didn't jump for over a month as his neck healed.

I know this might be one in a million, but would a scenario like this give a bit more credence to a track helping to cause an opening of unusually severe forces?

ltdiver

Don't tell me the sky's the limit when there are footprints on the moon

[Remster 24]

Speculation mode...

perhaps dumping in a track resulst in hard openings, not because of the extra total velocity (I guess it is not that much faster if the couple of posts above are accurate, and they look like it), but maybe because of the way to shock is transfered to the body.

If the opening happens while falling down the tube (or relativaly vertical) then the only velocity being killed is the vertical one, and the way the harness is made, and attachment points for the risers are positioned, the shock is absorbed by the body in the way the rigging system was design to do so.

If opening in a track, the entire horizontal speed gets killed (most of it anyways) and this has to pull back the jumper and jerk the body arround.

What do you think?

Remster

[nacmacfeegle 0]

I would say that the selction of a canopy that will open consistently smoothly is an important facet of gear selection for any type of jumping. Flyhi correctly points this out in his initial post.

However, I think people are missing a big issue here.
IMHO a canopy that opens on heading consistently is probably a bigger consideration that specifically applies to big ways.

--------------------

He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. Thomas Jefferson

[Samurai136 0]

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I'm yet to dump my Jedei in a sit (stupid clouds), but at full track its not that bad of an opening at all. On video I'm typically the first out of frame and I tend to be one of the longer trackers on all the RW stuff I've done so I've still gots lots of forward speed.

I've dumped in a trrack w/ my Samurai; it left a few minor raspberries on my shoulder. It wasn't hard. The Samurai has a pretty big slider and the airlocks slow/smooth the inflation process to some degree. Had a premature deployment in a sit at 157mph. That was reasonably soft. Unexpected but no injuries, aches or bruises. I kept jumping that day after I got a new PC put on the canopy.


Ken

"Buttons aren't toys." - Trillian
Ken

[quade 3]

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Yes, well, what if the tracker was doing something a bit more (or alot more) steep than the most horizontal and perfect track?

Well, obviously if a person is doing more headdown than tracking the speeds can be -quite- high and possibly exceed the TSO of the harness, container and reserve, but I stand by my statements and math that -tracking- in and of itself isn't the main issue.

quade -
The World's Most Boring Skydiver