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It may sound confusing at first, so refer to the attached picture. Also picture is not drawn to scale.

Alright, trying to redeem myself from that last one, I thought of an idea to reduce if not get rid of line twists and 180's. The idea, is to stow the left riser and right riser line sets separately, to prevent any kind of twists.

First taking the left riser line set and running a figure 8 in an up and down relation; up towards our heads and down to our feet. It is placed on the left side of the container. The same is done on the right. Then you have a long flap that folds from the inside to the outside covering the lines and two locking flaps that slide into slits in the container. The lines then meet at the bottom of the tray.

Theoretically, you should have a very very slim chance of line twists or 180's. Let me know what yall think, I am curious to know on this one!

Dale

Can you explain how/why such a setup would change the incidence of line twists and off heading openings?

Also, are the lines stowed on the canopy, as per standard gear configuration (hence, requiring some weird shaped tail pockets that would stretch way up the topskin of the center cell)? Or are they in the pack tray?

Putting the lines in the pack tray is an interesting idea (and potentially a good one--I know a couple people who've tried moving their tail pockets down there). But it would, in my opinion, have some potential for serious negative consequences in the event of an unstable deployment in which the jumper's body impacted or entangled the lines (because getting tangled in the bottom of your lines is a much better--and slower--situation than getting tangled in the top of them, which looks to be pretty quickly fatal).

Another thought:

Are you proposing extremely short risers on this rig? I see that you have the end of the riser at the top of the pack tray, and I'm not clear on how it got up there. Is it a very short riser, or is it somehow doubled, or folded back over to get back to the top of the tray?

And somewhat related to that: Do the lines come around the canopy at the top or the bottom of the pack tray?

Looking at it again, I'm guessing you've left the lines in the pack tray, used ultra short risers, and the "line pockets" are open both top and bottom? Is that right?

Hey Dale,

keep those ideas coming man! For every ten ideas you give us, expect nine to be shot down. But who knows, maybe you'll invent the ultimate anti-offheading solution!

I've been wrapping my head around the idea in this post and I have yet to find a showstopper.

I don't think it'll completely avoid line-overs and offheadings, but I do believe it could lessen their chance. If you consider that some jumpers push the risers to the outside upon opening (or when doing roll-overs) this would effectively help doing the same. The inertia required to twist a canopy with its risers and lines separated is a lot bigger than with the lines all close together.

It is a big paradigm shift in that we no longer stow the lines in a pocket on the canopy, but now in the container. That means the canopy pulls the lines out of the container, instead of the container pulling the lines out of the canopy. I'm not sure yet what effect this has, and I expect such a system would require new ways to stage slider-up opening sequences.

Cheers,

Jaap

Because the inertia required to turn a canopy with the risers and lines seperated is bigger than with the lines and risers together.

How do you fix line-twist (aside from making sure you're flying away from the object)? By pulling the risers apart (and kicking your legs if you can).

This would effectively do this, all the way up to the top of the canopy (where they would still come together to where the slider is quartered I imagine).

I'm just doing some hand waving here, but I think it's an interesting idea.

Hello,
That was a common pre tail pocket method,
and still in use for most short delay round deployment.
Avery

In my experience, the vast majority of slider down line twists occur due to the motion of the jumpers body under the canopy, not due to the canopy twisting as it moves to line stretch. Virtually every time I see slider down line twists, they develop after the canopy is at least partially inflated, as the jumpers body is spun around (or because it was unstable and spinning to begin with) to match (and in this case swing well past) the canopy heading.

The part where I marked the end of the risers was kind of mistaken. I am not sure how far down into the pack tray they run, but run them as far down on the left side, then figure 8 on the lines on top of it, making sure that the last loop is going down and coming out from under the flap at the bottom of the tray. I will put another picture up, of what it looks like with the flaps closed and where the canopy would lay.

Dale

What will happen when one side of the "line pack trays" opens, or hesitates and does not play out line evenley? You might have a canopy that starts to inflate with one side of the susp. lines a foot or more shorter than the other side due to it being hung up. Do you think it will be better to close them with velcro, or tuck tabs to ensure a reliable even opening of both sides at the same time?

In Bill's recent wall strike the canopy left the container 90 left. There was a white logo on the front RHS of the canopy that can clearly be seen all the way to opening. His body position looked good and stable.

Any ideas on that, Tom? This never really was discussed in the original thread.

The locking tabs are meant to be tuck tabs. Hell you could use velcro if you want. Those two extending tabs on the bigger flap are what I think of "Tuck Tabs".



I can see body position affecting it with design still, but this could possibly fix a packed off heading, and if the PC pulls the canopy to an off heading.

Here is another picture of what it looks liek with the lines stowed and the canopy laying on top. The Red outline is the canopy .

Dale

What is used to stage the deployment? Currently we use a primary stow. What with this system slows line dump, before canopy inflation?

Why do you need them to "close" at all? Would just a loose flap work? Or even just freestowing the lines in two groups, one on each side of the pack tray?

Nope. I've really got no ideas, aside from "sometimes that shit happens."

A loose flap could work although I really don't know. The reason I would design it with a closing flap, is a cleaner tray(lines won't push out), and it will help to keep the lines nice, neat and in place.

As I don't own a BASE container, I am planning on trying to sew one together with existing parts as close as I can see from pictures, and using an old 7 cell cloud canopy I own. I could dummy weight it and test drop it from the cliffs at my local lake back home, or possibly a bridge around there. I really wish I could get my hands on Buster from Mythbusters though. A weighted manakin would help the best, cause he will have an actual body position in the harness, instead of the bag and crap I used to use.

Dale

Yea I could see just placing the lines like he shows under the canopy. I was thinking he was going to have 2 seperate pockets seperate from the main pack tray that needed to be secured somehow.

Apex has one that they've used for test drops. From talking to Todd a long time ago, I think unmanned test drops are pretty destructive to the gear.

Unless someone wants to do the test drops , my only other thought would be a Remote Controlled Manakin. So you could flare instead of it slamming and rolling into the ground. A lot of work, but I would like to test with the real size equipment instead of a scaled down version, I don't think it would be as accurate.

Dale

It should be very easy to just simulate the system by free stowing the lines up the sides fo the container. You could also improvise some kind of covers if you happened to have a spair container you could attach them to. And if you lived in Twin Falls, you could run out and try it pretty easily. And if there was a bored jumper from Canada in town, you might even be able to convince him to side float and film the deployments.

Hmmm. I wonder if we can find someone who meets that criteria.

If I had the extra money I would be more than glad to pick up a used BASE container and sew the flaps in and loan it to someone to try. I don't have the jumping experience to try it myself . Although sounds like you have someone in mind for filming already!

Dale

wonder no more - I'll do it!

I just have one packjob to do tonight (even though I just squeezed two jumps in, a 2 way with Miles and then my first unpacked jump, a slider up McConkey (thanks for the pointers and help, Miles!), which also happened to be my first night span jump, and then I'm all over getting my bulletcam operational...




so Tom, are you volunteering to do the test jumps yourself, or am I going to be video-ing a dummy of sorts? ( I can't think how to avoid the pun there, sorry )

cya
sam

(less bored now, that McConkey scared me quite a lot, maybe black lines aren't the most reassuring option when you're looking down at your canopy hanging in the bridge's shadow and trying to see if all the lines look in the right place, damn black slider too )

 

I think you'll find if you refer to the original .jpg that orange man is already the test jumper for this mission. Unfortunately bag of dog food is on a tour giving seminars on safety with the kitten so unavailable.

I was thinking about the opening sequence with my idea. Normally the container/jumper is pulling the lines from the canopy. When this is happening, the risers are out and the lines are being drawn from the canopy. This gives the jumper a chance to drop a shoulder or go head down, which will give input to the canopy left shoulder down, pulling left riser, pulling the canopy to the left, off heading.

Theoretically, since the canopy is pulling the lines from the container, it doesn't have the force from the jumper pulling the lines out with the risers. Wouldn't the canopy begin inflating before the risers are pulled up and loading the jumper? If it begins to inflate prior to the jumpers body position effecting the risers, it should inflate onheading due to the separate line stows and the canopy should have already infalted enough for the jumpers body position to not matter much when the lines fully stretch and he/she is loaded with pull force of the canopy.

Let me know if I have thought to far into, or just totally off. Thanks.

Dale

There's basically no restriction to the lines as theypay out of the tailpocket. The offheading that results from a dipped shoulder happend because one side is loaded first and that side of the canopy begins to inflate before the other side.

In the time the canopy is travelling to linestretch, the biggest factor that will affect heading would be pilot chute oscillation or wind.

If you dip a shoulder, it's not going to matter where the lines were stowed. Once you hit the end of the lines and load the risers unevenly, that's where the problems start.

Added: You do not want the canopy to begin inflating before the lines are completely deployed!!! Especially on a slider down jump. Actually, ever. that's bad, bad, bad!

Do I understand well ?? Do you want the canopy to inflate before linestretch ?? Migh be a miscomprehension from my side.

What about making a system like Multi and then free stoving the lines behind an extra side wall attached to the bottom of the container. that would make a no resistant opening and first releasing the lines when there is line stretch this would also prevent tension knot.

That's the way I read it too. 87SupraT can you clarify? Is this what you meant?

If the canopy inflates before line stretch the opening is going to be very, very hard. The jumper will hit the end of the lines and experience a very sudden deceleration. I'd guess that if repeated, this kind of thing will rapidly destroy gear and/or jumper. At the very least you're going to see people getting knocked unconscious by hard openings on deep slider down delays.

Further, a canopy inflating before line stretch will throw slack lines around, which could encourage tension knots.

What about 2 seperate tailpockets about container width apart?

Again I don't speak from experience, just thinking. I see what yall mean on the extra hard openings. I didn't mean fully inflated canopy, but maybe the center cell catching air already.

The slack in the lines could creat a whip like reaction and the jumper will be on the end of it, so it wouldn't be good.

So what really needs to happen, is some how create something that keeps the left and right riser line sets from twisting, but at the same time if one is loaded more than the other to compensate on the other. Sounds like body position will always be a factor. Or just quit packing off-heading pilot chute openings .

This dual tailpocket idea sounds interesting too.

Line twists are generally caused by body position after line stretch. Adding stows in the pack tray to hold the lines might actually increase the chance of line twists if the stows don't open't evenly.

i would also say that whit the system you are thinking of there would be some packing issues I gues.. I'm not a BASE jumper, but I have seen some BASE rigs being packed, and the way I see it you make sure that the lines from both the left and right risers are stowed "straight" if you know what i mean, is because you can pull the container up against yourself when stowing the lines in the tailpocket.
In your system though as far as I can see you would have to do it the other way around, stowing the lines starting with the risers and therefor the left and the right lines seperate from eachother, you S folds or how you are planning on stowing the lines has to be pretty precise the same lenght to not get a unsymetrical opening... This adds some complications to the packjob as far as I can see, but maybe I'm wrong... Hope you get the point, my english isn't the best..

Simon

That is an interesting point. You'd have to either drag the canopy towards you while you stowed the lines, or move the container a bit at a time for each stow.

That's what you do when you pack rounds. Didn't you pack my round, that one time?

Yeah, but How much can you mess up a round packjob?

 

But you don't have to run before you theorize about running. In fact, sometimes it can be beneficial to have never ran before so our minds are not yet clouded by the age-old tradition of having to put one foot in front of the other.


And so he did.

But you don't have to run before you theorize about running. In fact, sometimes it can be beneficial to have never ran before so our minds are not yet clouded by the age-old tradition of having to put one foot in front of the other.


Definently.... I think it's cool that you come up with these ideas, especially when some of the really experienced people in here, think that some of it actually could work.

Beeing a non BASE jumper myself, but very interrestet in BASE I like to read all the stuff in here, and I like to write question and replys to the stuff people says, if I think I have something seriously to say about the subject. And if he like me is very interrestet in BASE gear, and BASE jumping overall, I think its ccol... So keep'em ideas comming..

Simon

Don't let the jump number blind you. Just because I haven’t jumped a lot, doesn't mean I quit learning about it all. Body flight and parachuting has consumed me for the last year and a half. I have become obsessed with it all, why, I don't know. I haven’t jumped for about year so it can't be that, maybe just my fascination with it?

I am about to start working towards getting my rigging certification, and I pack parachutes every weekend on my local DZ. I have designed and built my own elliptical parachute, but I don't plan on jumping now, maybe sometime down the road when I have the experience and on a 3 parachute system. So I feel I have a "Basic understanding of skydiving gear".

I do plan on pursuing BASE, but much later on, after I have the canopy experience and the right mind set for it. I watch/analyze jump videos, just to help me better understand what/why/how something happened.

This idea about the container design came the other day, shared it with Jaap, and decided to post it to see what others thought. Would it work, not sure, that is why I ask. Like I said before, I don't speak from experience, I am asking here for feedback from experienced jumpers and more knowledgeable people.

Thanks for the support and feedback guys, I will let yall know if I think of anything worthwhile :).

Dale

There are definitely things that you just can't learn from theory.

But there are also things that you don't pick up from any amount of practice.

I think that both (theory and practice) are pretty necessary.

87SupraT, just be sure that you get some practice in before you try to implement the theory. An internet forum is not a good place to actually learn to BASE jump.

 

It can help, but what is more crucial is a solid understanding of physics and engineering.


Maybe his assumptions are wrong, maybe not. But people expose the flaws and in the process he (and potentially some other people including myself) learned something.


I think we're jumping to conclusions too early here. Can you explain why you think there would be increased chances of friction knots?

It is easily proven in a simple experiment that a disc resting on top of a single axis is easier to spin around than a disc resting on top of two pillars that have an outward force applied to them. Whether or not this idea translates to a parachuting environment is an interesting thought experiment at the very least.


Why is this dangerous? I don't see anybody sewing up his design and test jumping it with a life human. In fact, 87SupraT himself mentioned the use of a test dummy. See it more like somebody throwing toys off a bridge for fun.

As BASE jumpers we should welcome these enthusiastic people with open arms, however inexperienced they may be. If their ideas are stupid, we can tell them politely. BASE is supposed to be a sport with open minded people willing to go against the society induced tradition that it is impossible and suicide to leap from fixed objects. I'm a little dissappointed to see ideas like this shot down so hostile. Why treat these ideas the same way society treats BASE?

Assuming that 87SupraT is going to be the next Leonardo Da Vinci would be silly, until he proves us wrong. But flat out denying there might not be a Leonardo Da Vinci among the many excited people that come up with funky ideas goes against the spirit of BASE.

I disagree. While both are going to be useful, I think that a practical knowledge of parachute rigging and BASE is going to be far more critical than any amount of physics and engineering background.

I would, in other words, rather have my BASE gear designed by Martin Tilley than Jean Potvin.

If I planned on jumping the gear in actual BASE environments, I absolutely agree.


Fair enough. What I'm trying to say is that there have been inventors that didn't necessarily have an established background or experience in a certain field and yet managed to come up with an invention that revolutionized the field. As BASE jumpers, we can be receptive to such ideas without compromising safety or losing respect for history and established standards and traditions.

I completely agree with you, I don't wish to learn to BASE jump from the internet, but possibly pick up some theory/gear knowledge. It is hard to find someone that will accept me to ground crew because of my low number of jumps :/. This is really the only way to learn about it the right way, correct?


I built it in my dorm last year, and yes I kited it about 50 feet above me for awhile :). Not too maneuverable at the moment, it needs to be relined with the proper trim. Ripstop nylon is quite expensive, so I used the lightest non-breathable fabric the sewing shop had. I have some pictures of it; if you like I can send them to you.

Perhaps you might find more sympathy here if you explained what is stopping you from gaining more skydiving experience.

Be forewarned that a lack of money is a poor excuse. I knew a guy who worked thirty hours a week besides fulltime college to fund his passion and then rode his bicycle twenty miles to the neareast dropzone because he didn't have a car.

That's dedication...

Truthfully, I am still scared of the responsibility as soon as my foot leaves that plane. I got banged up on my 1st jump and broke my tailbone. Took the wind out of my sails, but I managed to make myself do a 2nd jump to see if it was for me. I live 5 hours from my dropzone during summer and december.

As a solution I have become a fulltime weekend packer and the DZ is keeping all the money I make in their account out there. It will keep me from impulsively buying something dumb I don't need :). Being out there alot helps to reassure myself to start again.

Dale