Pin Tension on Solos

[JaapSuter 0]

Hi,

here's another one of those silly questions for ya.

How do you trust your pen-tension if you do a solo or virtual groundcrew jump? Pin-tension will always change a little when you gear up and tighten the chest- and leg-straps. By then, you can't reach back and feel your pins anymore, nor do you have a friend to do a pin-check.

One could do some tests when you have friends around, maybe even using a fishscale. Do you just trust these results and how they carry over to a new situation? In other words, if you're wearing the same clothes and body armour, do you think the rest variation (strap tightening) will be small enough to be neglectible?

Mmmm, maybe I should grab my velcro rig for this one...

I feel like I'm asking a stupid question, but last time I didn't ask my canopy opened a little lower than usual, so here goes.

Thanks,

Jaap

p.s. No, I'm not doing true solos.

[leroydb 0]

i did a sloppy packjob, then put my gargoyle on. had a friend use a fish scale. I balled up in a dearched funky position... Hardest pull was 15lbs. I think velcro is 12 lbs. on the the other end i had pull tension down to 2lbs on the top and 4 on the bottom pin...

your mileage may vary....

edit to add: this is just one aspect...

Leroy


..I knew I was an unwanted baby when I saw my bath toys were a toaster and a radio...

[DexterBase 0]

In that situation, you kind of just need to trust yourself.

Is you packjob consistant?

If so, it's unlikely that your pin tension will have changed all that much since your last ten jumps that it was fine for.

Is the jump super low?

If you're really sketched out about it, then prime your pins half way and put your rig on.

The amount of drag a PC creates will pop your pins. After even a relatively short delay, the pins will pop.

At the the object we took you to, I will jump with my pin flap closed, the pins buried, and a 42" PC. I rarely get a pincheck.

[Faber 0]

Heya dude
a jump whith out people on the ground or nearby knowing off you jumping is a true solo,also as you use phonecrew..
the difference is that on your solo nobody can reach you whith in a few mins to help you in case you get hurt,dont fol your self or be heroic on this.. jumping off an object were nobody nearby knows what your up to can give you loads of trouble if the jump aint happening as sopoused...

to your main Q
i dunno why but i always prime my pins ½ on all my jumps(bear in mind that i max has 4 secs of freefall).It were a thing i were taught to do as i started and i feel good about so.
I dont think it should give a problem aslong you plan a flat n stabel jump,if you want to do flippy things im not sure i want to do so from the risk of a poped pin...

do as you feel is the correct and dont forget to have some kind of crew somewere that can call for help in case you dont call back...

as i know the feeling about asking people to do this you could call me at msn and ill give you the tips ive found by the way.Its common thinking but usaly we tend to think common by "small" aspects.

Stay safe
Stefan Faber

[hookitt 0]

On lower jumps I use a longer closing loop. It's probably not necessary but gives me piece of mind.

I don't know about you but I can reach the lower pin with my left hand. I always make sure it's oriented properly and sometimes push it in and pull it back out a bit while I'm wearing it. If it moves easy, I'm confident it will pop easy.

The top pin... well, set it where you want it and that's that. On my rig, it moves easier than the bottom anyway.

The fish scale trick is a good one to get familiar with your equipment. Curl up as suggested by Leroy and test that way too. That's the extreme end of the spectrum. Go back to a relaxed arch, or whatever position you tend to be in at pull time, and test it that way too.

I'm simply too paranoid to fully seat the pin unless it's a terminal or close to terminal jump. The bottom of the pin always at toward the bottom of the rig and is verified by grabbing it with my left hand after I put the rig on, and probably 10 more times before I jump.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[JaapSuter 0]

Thanks for the replies everybody.

Just to clarify some more; I'm not actually doing true solos. I have done a virtual groundcrew jump but I don't think I'll be doing another one again soon. My question also applies when you're alone on top of an object and your groundcrew is somewhere else.

Now that we're talking about pins anyway, another question I have is related to the positioning of the pins.

I don't want to discuss priming or whether you do smiley or frowny. I'm curious which way people orient their pins in relation to the tuck flap you close last. My Warlock has such a flap, and I believe most other pin-rigs as well.

Because that tuck flap hinges on the left and opens from the right, I like to stick my pins in from the left towards the right. That means the bridle needs to pull to the left to take out the pin. This side has the most clearance because the tuck flap is on the other side.

I know that really the bridle pulls upwards more than sidewards, but there's always at least some sideways movement.

I've seen at least one other very experienced jumper put in the pins from the other side. This was mostly because putting the pin into the closing loop is easier that way (since the pulling cord is pulled down to the right when you close it, the opening of the closing loop is exposed to the left, effectively making it easier to put it in the opposite way of what I described above).



Holy crap, I don't think this post makes any sense unless you grab a pin rig and experiment along. I'm guessing it doesn't matter much from which way you enter the pins as both seem to work for a number of jumpers. Regardless, have you ever thought if you go from left to right or right to left and what was your reasoning for using one over the other?

Thanks,

Jaap

[hookitt 0]

From the bottom towards the top is how I put mine. The hinge and the pin can't come in contact that way. Once the bottom pin is pulled, it's a non factor.

I don't like the idea of left to right.. or as you said, from the hinge. If the pin is primed, it can touch the hinge part on some rigs. With a tight flap it could possibly hinder the extraction.

I have seen PC's tow for a second or 2 and the pins started from left to right and possibly a little more from the top downward.

It's always made sense to me mechanically to insert from the bottom.

PS: I'm postwhoring and packing at the same time so if you want me to look at anything while I'm doing it just say the word.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[GaryP 0]

Quote

Because that tuck flap hinges on the left and opens from the right, I like to stick my pins in from the left towards the right. That means the bridle needs to pull to the left to take out the pin.

(stuff snipped)

I'm guessing it doesn't matter much from which way you enter the pins as both seem to work for a number of jumpers. Regardless, have you ever thought if you go from left to right or right to left and what was your reasoning for using one over the other?

Thanks,

Jaap

Actually, it does make a BIG difference which way you place the pins. The tuck-flap does favour a bridle & pin placement in a particular direction but it is the way the pins have been sewn to the bridle that determines the way the pins should be inserted into the loops, regardless of the tuck-flap positioning.

Ideally the pins should be sewn to the bridle that favours (compliments) the opening of the tuck-flap but I've seen bridles on 2-pin rigs that have the pins sewn in the opposite direction to the norm. It's important to orient the pins & bridle so that it pulls at the "eye" of the pin in a way that it does not force the end of the pin down into the flap and cause a pin-lock.

This problem is with fixed, sewn pins as they are usually attached to the bridle with a loop of sewn webbing that rotates around the "eye" of the pin to pull on either one side or the other.

Check out the attached drawing - pls excuse my lack of artistic flair. It should (hopefully) explain my point a bit better than all this verbal diaorrhea.

Check your bridles.

Hope this helps
Love your work Jaap

g.
OzBASE86

EDIT: - Update - info from crwper's post shows that floating pins are succeptable to this problem as well. I had originally said they weren't. Thx Michael.

[crwper 7]

Quote

It's important to orient the pins & bridle so that it pulls at the "eye" of the pin in a way that it does not force the end of the pin down into the flap and cause a pin-lock.

I watched a pilot chute in tow malfunction caused by this exact problem on a CRW jump. The problem there was that we were using floating pins, and it's easy to install the pin "the wrong way". I just wanted to add that this is a really subtle rigging error, but can have disasterous consequences. Make sure that when you pull up on the bridle, it lifts the end of the pin up into a "U" shape instead of forcing it down into the flap.

Michael

[K763 0]

Hi Jaap-

For those times you are concerned about pin tension, you can also change your closing loop to the Spectra material. It provides much less friction for an easier pin pull. Of course, with less friction and easier pin pull you have the obvious potential problem of premature container opening, so care and good judgement should be used when reconfiguring your gear in this manner...(as always).

Peace,
K

[Bryguy1224 11]

I have always been told that closing pins where designed to come out with the same pull force and the same way no matter what direction they where facing. With the exception of so much tension that it can't be pulled. That's why they where designed the "U" shape. Obviously a straight pin would pull out differently if it was up or down. With the curved pin it shouldn't matter.

Ody

[TomAiello 25]

Quote

I have always been told that closing pins where designed to come out with the same pull force and the same way no matter what direction they where facing. With the exception of so much tension that it can't be pulled. That's why they where designed the "U" shape.

I've heard the same thing, firsthand, from an extremely authoritative source.

I admit that I spent some time playing with my pins today, though. (cue skinflicka for witty comment here...)

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[crwper 7]

At the risk of adding yet another crummy diagram to this thread, you'll find my rendition of the problem attached. Let me first note, we only noticed the problem with the floating bridle for CRW, which is essentially just a piece of 900 lb Dacron running through the eye of the pin. With this setup, it's not obvious, but there are two very different ways to route the line through the pin. I suppose I should add that, in the accompanying diagrams, the pilot chute is pulling from the bottom right.

In the diagram labeled "bad", pulling the bridle toward you (i.e. out of the screen) forces the end of the pin into the container. Most of the time this will clear itself, but it can result in a pilot chute in tow.

In the diagram labeled "good", the same pull will result in the pin being arched away from the container, as it's supposed to.

Although the problem is easily duplicated with a 900 lb dacron line, I don't think I've been able to duplicate it with a regular bridle. It could be that this condition is very unlikely with that kind of setup. I think the difference is that if we put the bridle attachment on the "wrong" side of the pin, it will just slide around to the right side, whereas with the Dacron line it winds up kind of locked in place. So, I think the condition is not likely to occur with the bridles we use in BASE, but perhaps others can try to duplicate it on their own gear.

Michael

Edited to add: I also forgot to draw the closing loop, which should be imagined in the obvious location.

[JaapSuter 0]

Thanks everybody! Once again the experienced jumpers prove that not everything in base is simple and obvious.

To add one last question about pins; why do you trust the points where the pins connect to the bridle? Are you a rigger yourself, have you done tensile tests, or do you just inspect and then trust the material that comes from the manufacturer? This is probably just paranoia, but it would really suck if the closing loop tension is stronger than the pin-to-bridle connection point resulting in the bridle ripping off your with the pins still in the loop.

I suppose with a correctly manufacturered bridle the bartacks will have much greater breaking strength than what any pin-tension or PC drag can ever create, but considering the deadliness of a break there, it's just one of those points that have me worried.

Sure does put velcro-rigs in perspective eh?

Cheers,

Jaap Suter

[lifewithoutanet 0]

Quote

To add one last question about pins; why do you trust the points where the pins connect to the bridle? Are you a rigger yourself, have you done tensile tests, or do you just inspect and then trust the material that comes from the manufacturer? This is probably just paranoia, but it would really suck if the closing loop tension is stronger than the pin-to-bridle connection point resulting in the bridle ripping off your with the pins still in the loop.

You know, I've wondered about this, too. I've inspected my bridles and wondered just what the tensile strenght of those points is, but overall just trusted them rather blindly, knowing that they were designed to work, that they continue to work and that I inspect them frequently. As an aside, I'm rather paranoid about my pin-tension and keep mine not "loose" but definitely not super-tight. I also prime mine before every jump and have them checked/re-primed prior to exit.

One thing I've thought about is the feasibility of routing a cutaway system of sorts that would hold the closing loop in place not by a knot and washer, but by a cutaway cable. In my two-pin rigs this would add some rigidity to the top and bottom flaps. What I'm really not sure of is the angles/corners that the cable would have to go through for the bottom flap and whether or not that would add too greatly to the pull tension if I were to cutaway my closing loops. Also, since I'm somewhat loose on my pin-tension, is it really necessary? And of course, is it adding more complexity to the system?

-C.

[cornishe 0]

Quote

Mmmm, maybe I should grab my velcro rig for this one...

You know my opinion, Jaap.

Listen to all this complexity in closing loop tension, pin checks, wtf. What's wrong with good ol' velcro? For 95% of jumps, NOTHING, that's what. It's not worth the extra complexity for me.

I made a solo jump last night. Didnt have to check any pins, and I primed my velcro shrivel flap all by myself.

I don't even like giving pin checks. It's your jump, your responsibility. If you can't check your own gear to your satisfacton alone, don't jump.

Seven Q's Bongo,
Abbie

Abbie Mashaal
Skydive Idaho
Snake River Skydiving
TandemBASE

[pringles 0]

here is a thread for your worries about pins comming off the bridle.



http://dropzone.com/cgi-bin/forum/gforum.cgi?post=1280959;search_string=pin;#1280959
You will need to go to the top of the post to get the whole story. There are pics for you to see also. Your worst dreams will come true.

I will continue to jump my pin rig though. I do check over my attachments very thorough. I think this is a very fluke happening. That doesn't mean that it cant happen to you or me though.

Matt Davies