Basejumper.com - archive

Curious to hear thoughts on ABX and Squirrels opinion (NBS) on it. Squirrel seems to like the round bartacks though.

http://www.squirrel.ws/equipment/base-jumping/stream

When I first saw the ABX tack, part of me was scared, and part of me thought that this was maybe the new direction harnesses would take. I think the second was the correct response. I do not own a squirrel container, but thats a pretty goddamn good looking rig.

Funny how at first the 'No BS' harness section had a paragraph with a snide and jealous-sounding commentary on a competitor's product which has now been removed.

Regardless of what you actually think about their products, I doubt that squirrel is "jealous" of anyone. In 3 years they have gone from nothing to the largest producer of wingsuits, by a fairly wide margin I would bet, and are near the top if not at the top in production of canopies and containers as well. They have changed what people expect when they order a wingsuit as far as production time and customer service. If Matt wrote it, snide is probably an accurate word, but jealous, never.

Now, lets get back to a technical discussion of those crazy circle bar tacks. Any climber type people that know when they started showing up on harnesses?

Nice tread!
Anyone has experience (and want to share) with ABX system on
Adrenalinbase's containers?

Safe jumps
Mario

Misty Mountain has been bartacking like that for years.
BD currently has their bartacks in the shape of the logo.

The need of making a base harness to also act like a climbing harness has long been needed in the sport.

side rant...
Adrenaline made the ABX. Squirrel makes the Stream.
APEX, Asylum.... they all have something to offer the sport. People should be grateful Matt started squirrel. It has pushed ALL manufatures to produce even better equipment and allow the sport to progress in the direction it has.

Are they reinventing the wheel? Maybe. I don't know.But they sure as fak are making it roll better

Just a climber-y thought...dyneema has issues with shock loading, right?

Video of 170lb weight falling only the length of a dyneema sling (https://vimeo.com/53157265)

Did squirrel do shock-load failure testing on the NBS? It'd need to be able to handle the shock of a full terminal slider down opening at least I'd think.

That video is way out of context, and has no relevance to its use on harness.

That sling has a knot in it, and it is the heat of the friction within the knot when suddenly tightening that melts and weakens it to fail at low impact loads. It is generally known that you should not tie knots in dyneema because of that. Sewn dyneema fails at or above the 'advertised' loads, which the manufacturer would have looked at when selecting the webbing.

If you manage to break the harness' dyneema webbing in a hard opening you have more pressing issues to deal with than a broken harness, like being dead from a broken neck fro example

I agree it's way out of context and has almost no relevance.

I thought that, even unknotted, it still had shock loading issues? I don't actually think there's anything remotely wrong with using it and the NBS harness...just curious.

The dyneema/nylon thing with regards 'shock loading' is the same as when talking differences between dacron/spectra/vectran. (Spectra is Dyneema under a different name)

Basically nylon stretches when loaded and absorbs some of the shock, whereas dyneema doesn't really stretch much, so any 'shocks' get passed on into whatever it is attached to.

In a climbing situation, or rather more relevant, when you are at a belay, the stuff attached to the sling is the anchor at one end and you at the other. So if you fall off the ledge and the sling is nylon some significant part of the forces get dissipated, which means you brush yourself off and your partner busts his arse laughing at you. If the sling is dyneema the full forces of your fall get transferred directly into you or the anchor, which means your own arse may get bust, or the anchor at the other end, which effectively means your arse still gets bust either way.

And, since you're loading a canopy as well as dacron lines before loading your harness...there's no shock loading.

The shock-loading is just when there isn't anything stretchy in the system at all.

Squirrel "largest producer of ws and canopy/ container"? Maybe in Murica but definitly not in Europe.
About their container, if you want lighter go for the Jackdawn and if you want more sexy go for LD3

You don't think squirrel produced more wingsuits than any other company in the year 2015? I would be shocked if they didn't, and wouldn't be surprised if they were double the next competitor. They have a production facility that no other manufacturer can match.

I wouldn't be surprised if they didn't lead in canopies or containers yet, but I'll bet it's pretty darn close. I should have one in about 2-3 weeks, I'll let everyone know how it looks. I found the styling on the strong light to be very... Functional, but this rig looks sick to me. LD3 is a nice looking container to be sure.

On European DZ almost everybody fly PF phantom or havok, and here at the exit i see at least as much vampire/ ridge than squirrel (for local people i mean). So i can t believe Squirrel sell twice than other because it s not what i see on the field. (i don t talk about squirrel boogie at brevent)
For the canopy, atair is far away than others here for sure and i see more Adrenalin rig than squirrel one too.
Probably not the same in USA, but USA are not the World neither.
I m not sponsored so really don t care about who sell more, who is the "best", i m just bored by squirrel commercial bullshit (and this time it looks like they understood because they removed the bullshit)

..not sure about this - i've read the words before it's been changed and have been pretty shocked. it's easy to distroy an image, but not to repair it after..

i see only two ways of marketing: commenting what's bad on other brands - or presenting whats innovative on your own. so it really doesn't matters if its been snide or jealous - if you have to officially difame others innovation to present your own 'BS' in better light - you just spent all your recognition to satisfy a narcissistic need. this might be a wellknown american way, but definitively not the way to explore to the european market.

nevertheless i was following up the fast progression and improvements with a big interest and yes thanks to squirrel all the market is fired up to develop really good things.

but i wonder if they just thought a lot of theory about ABX to call it a BS, or if they really tried it out. since i am jumping ABX i am feeling a huge difference, and in the end this matters more to me than any words.

back to technical: the combination of ABX and snatch to me is the best heading-tool on the market you can get so far beside of the classic known skills.

Pictures of the latest EU boogie in Texel. Count the Squirrel suits...

Squirrel: 20 new products in 3yrs.

Adrenaline, Atair and Phoenix-Fly: 20 new products in 3yrs.

I really wonder if they do all the testing in vietnam, or where they get their testpilots from. Never seem to run into fancy new shit on exits. But maybe it's just me and i'm blind.

At risk of sounding like a hater, I don't really like the design of the lift web riser junction. And as un-biased as possible here is why:
Firstly, It doesn't appear to have any confluence wrap either on the lift web or the risers (maybe I just can't see it). I will freely admit that I am unfamiliar with dyneema webbing but webbing is webbing and confluence wraps will make a joint even stronger.
Secondly, I don't think the round tacking is the best choice for this junction. It makes sense to me to use it where the load can be applied in multiple different directions or where webbing connects from multiple directions like the hip junction. The lift web confluence should be designed to pass all the load down the liftweb into the harness. We also already know from history that you do not want to present a point of stitching to a peel force (aka 4 point stitch or maybe the ark of a circle). I think they may have been better served with at least a horizontal tack at the point of separation to get as much thread as possible sharing the load.
Thirdly, It appears (I could be wrong here) that there is only a single layer lift web and that the diagonal runs over the shoulder and joins the lift web to form the rear riser. If so I really do not like that design as it will end up placing a lot more load on your stitching instead of the webbing.
I know they claim that they have pull tested their gear to blah blah blah. It will be interesting to see what mass field testing does to it.

Literally every post you write (here and on DZ.com) is related to the Godliness of PF, or a dig at Squirrel.

I just wrote what i can see around me, but you probably know better than me how it is here in Europe.

All I could think of in regards to your question was this

https://m.youtube.com/watch?v=QeoHcB9_wss

The snipey paragraph made me chuckle, but it was still a bit immature and unnecessary. I guess there is no love lost between Matt and Jean-Noel, which is fine too.

That being said, I don't get the brand war!! I think it's amazing with such a wide range of products and manufacturers to choose from. All this competition seems to have everyone hustling just a little bit extra to provide us, the customers, with some amazing products!

If I had the money I would need my own walk-in closet for all the gear I'd be ordering (probably a good thing I'm not rich).

Besides Tonysuit, which make a great product but has probably the industries worst customer service - shitty by any standard really - everyone has been great to me:

Robert sent me rubber soles free of charge some years back to replace my worn out leather booties on the V3.

Jean-Noel invited me to his factory when I was passing trough France to take all my measurements and provide information on the jumps in the area.

Matt went out of his way to replace my broken carbon fiber gripper after I accidently stepped on it. Met him in Chamonix by chance, he took it back to the States and had it sendt to me a week later.

Squirrel has without a doubt raised the bar in the industry, and that is something that benefits us all - regardless if you rock Phoenix-fly, Adrenalin, Atair, Apex, S-fly, etc etc.

Anyone have any comments on Fledglings thoughts or first hand info to address his concerns?

Yes sure, but the problem with Fledgling's thoughts is that it's not really a question about a specific point. It's his personal opinion about details and choices, and some guessing about a technology he says he's unfamiliar with. That's cool but to make an analogy, it would be similar to approach a new airplane company nowadays and tell them "hey guys I'm having concerns about the fact that your airplane is made of soldered pieces of aluminium. I'm afraid it will implode in flight because of fatigue cracks and anyways it's too heavy to fly". It's quite challenging to formulate an answer...

Dyneema, polyester, circular and otherwise shaped stitching patterns made with programmable machines have been used widely in fall protection harnesses for decades as well by a few of us in the form of basejumping harnesses for years. It's not like we got a new shiny polymer in a test tube and went all hyped "hey let's go make a rig with it"...

If you have a specific question and want factual data or want to discuss about the pros and cons of a choice vs another, I'll be happy to answer in detail.

But so far most of the posts in this thread are expressing opinions about the product or part of it, being it negative or positive, and I respect each of them, but it's not really an exchange about technical aspects asking for answers...

I like the top part of the Pin cover Flap (APEX-DP Style).... I wonder if its possible(and not dangerous) to make the bottom of the Pin cover Flap just the same way....

if you have Dacron lines it probably doesn't matter at all but I'd really like to see a Harness with some (very) elastic Material built somewhere in it to compensate for the occasional hard openings (or even make faster openings possible). (in the road-bike industry there was a switch toward softer frames on the vertical axis, its not cool to kick yourself anymore..)

PS.
I like the progress but this whole Brand-war thing is making me sick ...

I disagree, if someone knew enough to say that they had concerns about soldered aluminum cracking then it would be a reasonable point for discussion and a chance for people in the know to educate the rest of us. Same goes here, fledgling might be way off target with his thoughts, but they seem well founded to me, so if you know a thing to two, here's your chance to educate us.


So more specifically:

1) Confluence wraps seem pretty standard on gear, so, does the stream have them or not, and if not, how is their ommision justified? It's not enough to say you're ignoring an industry standard by doing this thing differently, and it's better, without an accompanying why.

2) The circular tacking seems less strong for the application it's being used for. The loading on a base harness loads quickly and fully every time it's used compared to other generic 'fall protection' applications you elude to (work harnesses, rock climbing, maybe?) where the loading doesn't occur at all if they don't fall, doesn't come with the shock loading if they use it mostly to repel, and during a genuine fall probably does not occur at terminal velocity. For the load application it sees, fledglings thoughts seem reasonable. A peel force at the edge of a circle will load more critically than a straight stitch at the joint. For me the joint is less effective. Since you offered, presenting factual data here would be appreciated, both in terms of overall joint strength and durability. Is it as strong, or more/less? Is it as durable or more/less. How much testing have you done?

3) I don't really understand fledglings third point here how a single layer lift web will put more load on the stitching, so I'll leave that alone for now until I understand what he meant.

Thanks Lucifer

My admission was in reference only to dyneema webbing. Rest assured I have a complete understanding of parachute harness designs and stitch patterns. I also think you can stop hyping "Programmable Stitch Patterns" "Computer Controlled Stitching" etc. Regardless of what machine or human makes a stitch it will either be good or not good. The only benefit of programmable tackers is speed of production.
Care to answer any of my "not real" questions about stitch design, confluence wraps or single layer lift webs?
For a change I am not trying to be a prick, and have no concern as I won't be jumping this gear. But I am really interested in the thought process that led to this particular design.

The most effective harness utilizes the strength of the webbing as much as possible with the stitching simply there to keep the webbing aligned while it does it's job. A traditional harness will have a double layer lift web that separates into the front and rear risers, this is where the rear diagonal crosses your shoulder and enters the joint. This way when you open you will load your harness at the legs (read end of lift web) up the lift web, through the risers to the canopy. I don't know about Squirrels design as no one has answered my question about the lift web. But it appears that it only has a single layer lift web (this will be the front riser) and that the rear diagonal crosses your shoulder and instead of terminating it becomes the rear riser. If this is the case then when you load your harness the load is only continuous through the front riser, to load the rear riser the load has to pass through the stitching at the chest junction. As I mentioned earlier the stitch of a harness should simply align the webbing and allow it to do the work. It seems to me that Squirrel's design means you will be loading the stitching on every single jump. I'm curious to see how this works out.

I'm much more worried about shock loading (read: our model of what makes fabric fail is wrong, it's not actually force)

Here's one without a knot for you

https://vimeo.com/27293337

Dyneema doesn't deal with shock loading so well. The model that says "Dyneema is as strong as steel because it can take a static load of X" is wrong. It actually takes very little force applied over a small distance to make it snap.

How long until a harness snaps on a base jumper?

Exactly 3 days.

care to elaborate??

I wonder what the properties of the blended Dyneema webbing are compared to straight Dyneema. Obviously squirrel did some strength testing to get the >31kn numbers, and I would imagine there's been plenty of static and dynamic testing. As others have pointed out, a fall on a climbing sling is a lot different than a slider up wingsuit opening, and the force isn't translated to a single point.

I'm not saying there aren't very valid questions being asked, but sometimes these tests aren't quite as applicable as one would hope. I remember the apex static line video that came out basically showing a 5 lbs weight being dropped and breaking the static line as a way to show how unsafe a single break cord system was. real world forces can be somewhat different than demonstrations with a lot of other variables being involved. Maybe this will actually turn into a good technical discussion after all.

I'm sure Asylum did testing on their 400lb Dacron too. I'd like to see a Stream/Jackdaw dragged through the dirt, left in the sun, thrown in salt water, and then tossed out of a plane slider down with a spectra canopy with an 80kg dummy. In all likelihood a complete harness failure resulting in a fatality will need to happen before manufacturers and buyers stop chasing lighter gear every season.

It's a reasonable point of discussion if it's aimed at starting an exchange. It's not if the goal is only to share a point of view or to criticize something one doesn't like. It might also not always be easy for me to discernate the signal among the noise of forum threads like this one and I apologize for emitting doubts about the usefulness of a serious answer.

I'll start by clearing one point first because it seems that many people tend to mix different ideas when it comes to evaluating the effort in the gear depending on the dynamics of the system.
It’s necessary to understand the main concept to understand the choices and construction details.


This is a misconception. It’s like saying the load doesn’t occur when the rig is on your back (which is true, but it doesn’t change the designing parameters). Both type of harnesses are made to withstand a maximum defined force because it’s an easy way to set a “safe limit”. If you assume a normal distribution and decent manufacturing reproductibility, you'll be able to load such a product hundreds or even thausands of times at 90% of the breaking load, without damage. So simply setting a minimum required strength before failure insures a basic minimal safety, then each product can be oversized to a certain extent to insure bigger lifespan or inspire confidence.

Now for legal responsibility of manufacturers, and maybe for the sake of selling as much as possible too, every user manual will tell you to change you gear after an impact, or to change your carabiner after it felt on the ground from more than 5m… Up to you to figure out where your margins are. If you dig into the studies and test reports about residual strength of carabiners that have been subject to impact on hard ground, you’ll understand why these recommendation have to be taken with a grain of salt. The most important aspect is by far to know the history of your gear.


The speed doesn’t matter.

I approach the “fall protection strategies” from another angle, because I've been confronted to the climbing environment way before discovering paragliding and basejumping. In each of these areas, the problem is the following : you have a human body accelerating towards mother earth because of the good old gravity. At some point, you have a very sorry human approaching a rock solid ground at a speed which is way higher than what he's able to absorb, but usually below 50(m/s) because of air drag.

We can see the human body as a nice machine engineered by natural selection which (when fully functional) is more or less able to survive an impact against something immuable like a tree or the ground up to a speed in the order of 10(m/s) - which includes a natural reflex tending to deccelerate as much as possible with the arms or legs when getting in contact - to protect the head and spine at all cost. It's quite satisfying, because it's also the same range of speed that humans can reach. That is when running for their life - before the wheel was invented - and let alone the combustion engine..
In between these two speeds (10 - 50 m/s), we have to slow down in the best possible way by other means. Unfortunately we cannot deccelerate the human body too fast, because it breaks apart.

Now you can have a quick look at this post, especially the second paragraph about opening, forces, and injuries. http://www.basejumper.com/...post=2955956#2955956

From experimentations made by others, we know that we can apply a 20g acceleration to a human body for a short time, and that it’s pointless to make the gear stronger to be able to widthstand a higher acceleration, because at this point it would’nt be saving a life anymore.

About the mass: when designing a product you can make as many sizes as you want, but you won't change each type of materials depending on the weight of the customer for obvious practical reasons. So there's an upper limit to define, wich is usually around 100kg, depending on the manufacturer's choice.

In real life, we want a harness able to destroy a human body before breaking. We decide it has to withstand a load around 20kN repetitively. So we fix a minimum breaking strength around 22kN in pretty much every possible configuration, loaded by only side, or completely upside down, etc.

Now if we apply a 20kN load to a 100kg body, this gives an acceleration of 20g. That perfectly makes sense, because a human being is able to survive a 20g acceleration for about half a second, but not much more, or not for a much longer period. Assuming terminal velocity (50m/s) that means that the worst case scenario we design our gear for is : stopping a falling human body from terminal velocity to zero, as fast as possible (to consume the minimum possible distance), but not too fast to avoid lethal injuries due to the decceleration.

So our worst case scenario in numbers looks like :

F = 20kN
m = 100Kg
a = -200m/s^2
initial speed = 50m/s
final speed = 0

...so assuming a linear decceleration, we’ll stop the human body in 0.25(s) over a distance of 6.25(m). That’s pretty hardcore, and that’s more or less what it looks like when you open a slider down canopy at terminal velocity. In real life, the distance is slightly bigger, and the decceleration takes a bit more time and is not linear, and the residual speed is not zero. But the peak of force is in this range.

The point is : the speed doesn’t matter. The human being structural strength is the limit. If the speed is only 25m/s, the maximum force we can apply to this body to stop it as fast as possible, but not too fast to keep it alive, is still the same. Around 20kN for a 100Kg human. The distance of decceleration will be shorter, and we could argue that it could be slightly optimized because the body can in real life sustain a slightly higher acceleration for a shorter time. But the general idea and the order of magnitude is still the same.

Conclusion :

Because of the second law of Newton, and the way the human being is made, the strength requirement is always the same no matter what you’re doing, and the only parameter to balance the strength with is the amount of injuries you tolerate before accepting a gear failure. That’s true for every situation where you apply a force on the human body via a harness.

Concerning the confusion with “shock load” and “Todd’s video about bridles” it’s still the same mechanism. The peak load on a system depends on the force applied to a mass.

The only things we need to know to evaluate this force is the mass, the initial and final speed, and the distance traveled. As the distance approach zero, the force (and thus the acceleration) approaches infinity. Et vice versa.

Sorry I’m out of time, I’ll come back later for confluence wraps and exotic materials...

You obviously have a lot of info to share but fuck that was a long winded re-direct to 3 pretty specific questions.
1) How do you feel about the lack of confluence wraps?
2) How do you feel about presenting a concentrated point of stitching to a peel load?
3) How do you feel about the rear risers not continuing down into the lift web? (Of course I am still unsure if this is actually the case but it really appears that way).

Again, for clarity. I am genuinely interested in this discussion.

1) I don't see how you believe relying on the stitching to be stronger than a continuous piece of webbing (yes I understand your concept of maximum load). Also better is not a great word to use here, my "better" would include more redundancy in the harness construction.
2) How do you feel about the peel force being applied to a concentrated point of stitching on every single jump? The front and rear risers will be loading the arc stitching due to the lack of a confluence wrap. For me it seems to be an obvious wear point and therefore less durable.
3) I don't understand how you think that confluence wraps will not add strength. You can argue their necessity not their effectiveness.
4) As I mentioned I am unfamiliar with Dyneema webbing. How do you feel it holds up to dirt and abrasion when compared to resin treated mil-spec nylon? I suspect it won't fare as well.
5) You have mentioned Polyester more than once. Is this in reference to the webbing or the thread? I would have additional concerns if polyester thread was being used.
6) And just for clarification for everyone reading. Are you answering these questions as someone in contact with Squirrel that knows their thoughts or somebody that simply has experience with these materials?

I'll only comment on the parts I think I can answer. I'm wondering the the polyester is supposed me be polyethylene, because that's what Dyneema is composed of. I very much doubt that squirrel is using anything but standard nylon thread for anything.

As far as how Dyneema webbing wears, can't saw from first hand experience, but spectra line is basically the exact same material in a different form, and sure seems to wear quite well. I would argue that lines get more dirt dust and grime on them than a container for most people, and few people seem to worry about dirt making their spectra lines dangerous. I have used woven Dyneema fabric for stash bags for at least 7 years, and recently made a base rig out of it. The abrasion and tear resistance have been far superior to similarly weighted nylon fabrics.

 
The data from that video is here



You can see the different forces with and without knots. If you discount the knotted slings which fail at half the rated strength, all other slings tested fail at around their rated strength of 22kn. On a slow pull you'd expect the slings to break a good few kn higher than the rated strength, but considering the heat generated in such tests it is good to see that they still take as much force as they are meant to.

So when you say


you are wrong. To snap a piece of undamaged dyneema with no knots/friction/etc you have to apply the same force they are rated for.

What makes fabric fail is force, always (short of dunking it in 100% sulphuric acid for a week. Unless it's a polyester/polyprop blend that is). So there's nothing wrong with anyone's model.

The problem with "shock loading", (which by the way is one of the most misunderstood and erroneously used semi-technical terms that gets bandied about, and i have an unhealthy hatred of the term) is not that it magically makes things break at lower forces than they are meant to, but that it generates higher forces than the mass load it's being applied, and in some circumstances the loads can be higher than the ones they are meant to take.

Going back to that table for illustration, a fall factor 1 drop of 120cm with an 80kg weight produces 22kn+ with a dyneema sling and 12.8kn with nylon.

It didn't make the dyneema break at 1kn, or at 12kn like you imply. It simply generated forces higher than the sling was meant to take, and so it failed. The nylon didn't fail because it stretched, limiting the forces by increasing the time the load is applied for until dissipated, and the peak force didn't reach the slings rated strength.

In base/skydiving, the harness is not meant to dissipate the opening forces. We use packing techniques/reefing for that, and somewhat stretchy lines for when we take that SO delay a little too long.

Taking a large FF2 onto a dyneema sling is the climber's equivalent of deploying a big cross-braced canopy slider off at terminal. You could have a harness made out of bungee but my money is on it not working out too well for you.

Dyneema is very strong, fairly inelastic, and highly resistant to abrasion, sunlight, and all sorts of chemical decomposition. It is a very impressive material.

Dyneema Properties: http://www.toyobo-global.com/.../seihin/tokutyou.htm

The Electric Harness Acid Test: http://blackdiamondequipment.com/...ab-acid-harness.html

Well there isn't very much that is standard on this rig so you never know :-)

I understand that Dyneema is Spectra etc. But I'm not sure I would consider the webbing to have the same wear properties as your lines. I guess we will see.

In base/skydiving, the harness is not meant to dissipate the opening forces. We use packing techniques/reefing for that, and somewhat stretchy lines for when we take that SO delay a little too long.

Meant or not meant... if there is a chance the differense 22.4 vs 12.8kn is going to save my back on a hard opening (or in the long term) im taking it...

Peace

That's a fair point. Like with most things 'lightweight' it is a matter of compromise. Same story as with dedicated WS canopies with vectran or spectra lines. Some people likes the peace of mind of having Dacron, others find the weight savings worth it and are happy jumping taking the occasional slammer.

It really depends what rocks your boat i guess.

Great post! Thanks!

Joe definitely spends a lot of time on these sites. Watch what you say or he'll hit you with facts.

Can t wait for these "facts"! (even if it s no relevant to this post)