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How much pressure is really created by the lines in order to realease the tailgate? Not looking for an exact measurement... just curious is it a huge amount of pressure where it would be physically impossible for it to hangup on a tan rubber cut in half without breaking the band?

Hello Sir,

Aren't you the same guy who was asking
about pilot chutes and delays for jumping
a 360' foot freestander that is 3500 MSL?

Is this a do-it-yourself-internet-BASE-FJC?

Keep in mind, people, me included, are
not being dicks when we caution jumpers
from entering the sport, especially if you
have zero instruction, mentoring, etc.

To answer your question: the band on
a tailgate does not break, it pops off
or sometimes just ends up being left
on 1 side of the tailgate after releasing.

hello sir,

are you the very proficient skydiver who keeps commenting on base issues drawing from his vast skydiving experience because his base experience is similar to his penis size(hint: i'm not talking about big issues, at least physically speaking, here)?
is this because he is an artist why i think he is a major cunt? i never was sensitive enough to appreciate the fine arts, sorry.
i hope we never meet though, cause with your mixed martial arts skillz you would surely kick my tiny little ass!

oh and by the way, some people do larks head the rubber band to the tailgate.
in case of a hangup it really does break!
who would have thought of that!!

edit: on a hang up, probably a even none larks headed rubber might break! hence the banning of black death rubber bandfs.

there! i said it! black death! uh-oh!

Yep, I'm the skydiver with 43 BASE jumps.

Nope, absolutely no desire to beat you up.

Your tailgate bands almost always break?

Hmm, how do you know?

The pressure varies widely, depending on:

(a) delay: shorter delay=less pressure
(b) tailgate location: further away from canopy on lines=less pressure
(c) some variables you probably can't change, like canopy size, jumper's weight and air density


Tailgate hangup factors:

1) Wrong rubber band
2) Tailgate location (ideal location is as close to the line attachments as possible)
3) Girth hitched (larksheaded) rubber band to tailgate
4) Short delay (especially PCA/static line)

In general, you can avoid the first 3 risk factors, so you should. To my knowledge, no one who has the correct rubber band, in the correct location, not tied on, has ever experienced a tailgate hangup.

Note that using tape, instead of a tailgate, allows adjustment of the "tailgate" location on every jump, so that it can be placed ideally on the fly.

Note also that the correct rubber bands are available, pre-cut to the correct (BASE specific) width, from the manufacturer for about 3 dollars per pound (Keener Rubber Company).

It's an amount of force that will break a tan elastic cut in half, but will not always break a black elastic cut in half. Which is to say, it's not so much force that you can't stop it by being retarded. I'd guess (for what that's worth) that it'll consistently break a whole tan elastic, but wouldn't bet the farm on it. If you went to two whole elastics, I suspect that your malfunction rate would become significant.

... But why experiment with this? A half tan elastic is known to work so well that I can't imagine building convincing evidence that a whole elastic works better. Are you BASE jumping in a scissors-impoverished region of the world? Trying to shorten up your packjobs by ten seconds? Or just curious?

no, but since i larkshead them i sometimes find them broken on the tailgate.i change them when they show wear so i suspect them to break due to a hangup.
which is absolutely no problem when placed and sized properly.
hard to tell what is a hangup, but i thought i witnessed some on fellow jumpers deployments.
most people i know larkshead it. philosphy thing i guess so no need to argue whats better.

I think the "larkshead or no" debate had relevance when people were using elastics that wouldn't break when they had to -- it'd be advantageous, then, to have an elastic that at least had a chance to roll completely off and didn't have "snag points". If you're using tan elastics cut in half, though, then I don't imagine it makes a bit of difference whether you larkshead them on or not -- with the possible (but doubtful, I think) exception of folks doing freefalls so low that a tenth of a second of hesitation might make a real difference.

will email you back about my experience :)

lol No I totally understand how the tailgate works... also that when you larks head it it will stay on one side... just curious about if it is really a great deal of force like if the band had to break because of some hang up or if the band was too tight if it would in fact break it? I have heard that the larks head can cause hang up on super low speed deployments...

I doubt that the larkshead has much to do with hangups if you're using the right elastics. However, though the elastic probably shouldn't break (but just roll off) in normal operation, you really, really want it to be able to break if it has to (ie, if it hangs up somehow). This is why choosing extra-strong elastics that you don't have to replace as often, and larksheading them on there, is a bad idea.

Just my 2 cents, but my feeling is that if you can identify several possible cause for a malfunction, you ought to do your best to eliminate all of them. Every tailgate hangup I'm aware of shared at least two of the following factors:

(a) misplaced tailgate
(b) incorrect rubber band
(c) rubber band tied to tailgate

If I can eliminate all three of those things, I will. What's the downside?

For the record, it looks to me like statistically, the best way to avoid a hangup is simply not to do PCA/static line jumps. That's the common factor in the most hangups. But I doubt we're going to convince most jumpers to stop doing those.

you know, not everyone learned with mentors. i didn't really have one so i had to read what others were doing. not as necessary today, but sometimes there is no alternative.

I agree completely, and don't larkshead elastics to my tailgate. But of the three factors, I'd say whether or not you larkshead the elastic on is the least likely to have any effect at all, and probably by a large margin.

Edit to add: That is, provided you're doing the other two right. If the elastics your using won't break, then having larksheading them on, in my opinion, becomes a very bad idea.

Yeah 460, but you're wicked sick genius

Naw, the trumpet guy emailed me and is
all cool in the gang... and hell I jump solo
a lot so the info I get on here helps me too.

 

Note also that the correct rubber bands are available, pre-cut to the correct (BASE specific) width, from the manufacturer for about 3 dollars per pound (Keener Rubber Company).
looked on website and found parachute section but siZes didn't match up with my cut measurements.

So I called and their closed. Is the tailgate size/width a speacial order you have to "ask" for?

So on that case do we order the " 1-1/4" x 3/8" " and ask for that size cut in half?

They keep the rubber in stock as long tubes. When you order it, they set the machine to cut the width you specify. They normally set it to cut the skydiving width (3/8"), but will set the machine to cut the BASE width (3/16") if you ask them to, and will not charge you any extra for that. They sell the rubber bands by the pound, and the price is the same regardless of the width cut (since they're just feeding them through a machine to do the cutting anyway). At least, that's the way they explained it to me.

If I recall correctly, I paid $3 per pound, which is about a fifth of what paragear charges, and with paragear you have to waste your time cutting them. I bought quite a lot of them, so if you're ever at the HomeBASE hostel, you can just grab some--I've probably got 15 pounds left in a hefty bag in the basement.

i larks head the band on my tailgate as well. i understand that their is that possibility for a hang up, but i think it's a very slight possibility, everything else being in check.

but i do it for two reasons...

one, i like to be able to reuse the same band multiple times...

and two, i'm not a tree hugger, but i don't like to litter unnecessarily.

i once spent a few minutes on the talus of tombstone and cleaned up at least 30 or 40 old bands and also found a handful of tailgates. some with bands larks headed too!

Don't give away the secret of free tailgates in Moab! Plus you got that free shirt off the talus.

_justin

haha! that's true... a nice Moab Brewery shirt... ha!

thanks for the good word frogman and thanks everyone for all the other imput... so I can gather from all this that a masterlock would not be a good tailgate? even if I take a full 2 seconds? ;)

You wouldn't get a line over for sure.

Did my first jump with a masking tape tail gate today since I couldn't find rubber bands antwhere in the house. Good thing I forgot about it otherwise I would have had a bit of gear fear I think. Worked well.

Actually, if you didn't attach it to a fixed point on the lines, but allowed it slide freely, it wouldn't be bad. You'd just have to be aware enough to unlock it for proper canopy flight--just after it smacked you in the head on opening.

 

So should we start a new topic "combination or key lock" ?

I've got my tailgate tacked in place with super tack and my band larksheaded onto it; the majority of my jumps are in the 200-300' range.

Am I setting myself up for a potential problem at some point down the road? How probable is a tailgate malfunction to the point where you are depending on the rubber band breaking?

potential... maybe. but in the last couple hundred jumps i've made from 190' - 270' i've had no noticeable hesitations or hang-ups. maybe i'm lucky, but i doubt it.

on the other hand, i have ended up in the trees twice now due to over-delay at a forgivable 300 footer.

No one can say for sure, but if you use the correct rubber band, you will probably be ok. Still, I'd prefer .05% chance of a hangup to .5%.



How often does your rubber band break?


Another thing I don't like about re-using the rubber bands:

You are relying on the rubber band on both sides of it's envelope--both to break if necessary, and also not to break prematurely. Using it for a lot of jumps reduces it's effectiveness, which might lead to a premature break (and basically a non-tailgated slider down deployment).


I will admit that I made several hundred jumps with a black rubber band tied to my tailgate, quite a while back. I switched my technique shortly after seeing a friend of mine impact under a still-tailgated canopy. He was uninjured, but the lesson was still pretty obvious.

I you are to order BASE specific tailgate bands I believe the size is 2 1/2 " length. When cut and laid out as a single strip. 3/16" width and .062 inches in thickness. Also the price is now 4.55 a pound from Keener.

Ody

http://solutions.3m.com/wps/portal/3M/en_US/painting_masking/painting_masking/product_information/scotch-blue_painters_tape/

100s of tailgates for only $3.

Grab a hand full of microline bands next

time you are at a big DZ or PD event...

Spend a few minutes with scissors

I can't believe so many people use tailgates. Why? Masking tape is the shit and you don't have to worry about it hanging up. Not to mention, it's unheard of, but an extra chunk of dacron running perpendicular to the rest of your lines is just one more thing that can cause a tension knot. Plus you can prime your masking tape for low shit by adding a little tear to the top of it. Tape is the shit.

That is false.

... Which I imagine is a bad idea for exactly the reason Tom states regarding re-using tailgate elastics too much. Using a thinner piece of tape I can imagine, since that'll still offer up some resistance but might hold back that little bit less for low-speed openings. But if you're going to tear the tape, I suspect you might as well not use it at all.

I have no data to support that, except the observation that stuff generally becomes profoundly easier to tear once it's gotten started.

I've only ever had one break. I normally replace then after 5-6 jumps and I take a look at them each time and if there is any damage or abrasion I replace them with new.

I use the custom ones from Keener, you can get a ton of them super cheap and the quality is much better than me trying to evenly cut one in half with a pair of scissors.

You could try "pinching" the tape around the lines (thanks Sparky for the suggestion) rather than wrapping it. I've switched to this method for slider-up packjobs after having a tape hangup at the Heliboogie last year.

On the one hand, I think this method is more prone to release prematurely than the tape wrapping method. However, on a slider-up jump the risk of a line-over is already reduced, and the pressure on lines to spread is lower, so I don't think this is a major issue.

On the plus side, I can't imagine a scenario where pinched masking tape would result in a malfunction. Whereas I'm living proof that wrapped masking tape can, although very rarely, fail to break.

You know that you're not supposed to use the whole roll, right?

Seriously, though, the original question is a good one. I'm sure that how quickly the lines are loaded makes a big difference in the peak force before the tailgate gives way, so studying it wouldn't be really straightforward, but I had set up an experiment shortly after I had a black elastic hang up that I never really finished. I've been getting into microcontrollers recently -- maybe I should revisit the experiment.

It'd be nice to know, for instance, how much lower the force is for two wraps of tape versus three, or pinched tape, or a tailgate with or without a larkshead, or with two wraps instead of three, etc...

there is actually a milspec for parachute equipment rubber bands. the spec is such that the bands will break within a certain load range. the tan bands from the previously mentioned manufacturer meet this spec. the use of the black bands or tube stows which claim more use are actually less safe. i don't know for sure but i assume the tailgate development was based upon a halved tan bands load capacity. other than laziness there is no reason not to use a halved tan band that meets the milspec.

How many rubber bands do you think 15lbs is?

After learning about tailgate hangups with the larks head, I started clove hitching the band to one side of the tailgate and making sure the subsequent wraps were distal to the hitch.

the clove hitch seems to have less bulk than the larks head, and its pretty easy to keep it out of the way. i suppose in theory it has more hangup potential than an un-attached band, but by inspection it just seems vanishingly unlikely.... thoughts?

My old mentor mentioned that instead of a tailgate he uses 2 to 4 tied off wraps of red riggers seal thread. He said he likes it because of the consistent breaking strength. Has anybody tried anything similar? I still just use the standard tailgate and rubber band method.

--Brian

I wonder, does anyone know if three separate wraps of tape take more or less force to open than if it were one continuous wrap, three times?

i have not tried the seal thread trick. my only concern would be that the loads may cause this to break to early in the deployment and thus negate the tailgate. have the manufacturers studied this to that degree of detail?

 alot of people are concerned about the maximum load factor of the rubberband, tape, thread..... does anyone know what the ideal breaking point is??? if so, could you please elaborate.

Enough that they need to be in a Hefty bag.

i believe the standard milspec rubber band breaks at 50lbs with a possible decrease of something like 12lbs being acceptable. the micro bands are probably the same, i'm not sure what cutting the band in half does for its load capacity but i might try a quick nonscientific test of some and report back. if Adam F or Marty T read this they probably have the answer.


FYI-micro bands are about 450 bands per pound

6750 cut in half = 13500 rubber bands

wow

I guess we have all chosen to ignore the "probability of improbability" or that "if it can, shit will happen"when practicing a sport like this. Whilst the engineering of rubber bands intrigues me (not) I would like some hard fact about what goes on behind/above me at pull time. Will a band break or will it be me broken with CD and control lines snugged into a tailgate? Anyone got any data on forces verses breaking strain etc? Further the tension of the first and second wrap of elastic will be disproportional to the last in a 3 wrap configuration, seems like a cert to hang up with reduced load. Warranty anyone!

While I have never seen any data on the forces generated by the rapidly-separating inner c-lines during deployment, we have troves of applied-science data. That is, there have been hundreds of thousands of BASE jumps with both elastics and tape used for tailgates with relatively few hang-ups. And the majority of hang-ups I've seen or read about have involved non-standard applications of the practice.

Based on field reports, in the most general of terms, if you larkshead or girth-hitch your elastic to your tailgate, you increase the likelihood of hang-up to some degree. If you use strange items to secure your tailgate, such as your hair tie or the cotton elastic keeper from your chest strap, you are probably playing with fire.

There are so many variants with deployment ie jumper weight, canopy size, speed of deployment etc all depending on an elastic band! Maybe we can find a few parameters and recommend X with Y etc. I would feel happier if I knew for sure that under a certain canopy inflating this type of band Will either break or come off the tailgate regardless of external factors. Maybe we need to source an number of different sized bands with controlled breaking strains, after all we use different sliders and PC's!

I noticed you made several posts on this topic. And I'm curious why. Truly curious, not being a troll.

It seems other factors in a BASE jump come closer to the realm of uncontrolled/experimental/unproven than the standard acceptable slider-off line-over prevention methodologies. I wonder why this is the topic that makes your pits sweat at the exit point.

My own fallibility seems to me a greater risk than the likelihood of a tailgate hang-up.

I guess its just about a natural survival instinct that makes me want to eliminate some physical factors that may/not alter my life span. Basically I question my trust in an elastic band, you?

I trust the elastic band. In my humble opinion, the tailgate is a beautifully simple device. It does a great job of preventing line-overs, is easy to use properly, has few failure modes (most of which are well (though not perfectly) understood and avoidable). And given the long-term and widespread use of the tailgate, it has been rigorously tested to function as expected when used as intended with a rigor that exceeds what most of us blindly accept in medical devices.

I and many others set the tailgate for roll-overs, and the triple-wrapped bands just pop right off. Given that some/much of the spanwise spread of the canopy has already begun to occur (compared to a packed jump) before inflation, the peak snatch forces separating the inner c-lines must be significantly reduced during such an event. So in proper configurations for packed jumps, I'm comfortable with the residual unknowns surrounding the tailgate elastic.

Now on the other hand, if someone wanted to tell me that my direct control configuration was beginning to get a little aggressive, and may result in a deployment sequence hesitation, I'd be all ears. But those slammer openings were killing me, sir, and I had to do something about it.

Justly said. Thank you for your help and input, it is appreciated. To answer your other question; currently jumping a notorious narrow gorge with high temperature fluctuations and tight rocky landings, guess this is what made me "sweat" last night. A tailgate hangup just kept me awake for some strange reason.

I asked Anne Helliwell once about this.
She told me that 2 wraps = 10 pounds
and 3 wraps = 15 pounds.

Appreciated. It seems from following a number of threads micro line bands cut in half break if they don't release, or at least those that have been tied to the rigging do.