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I have recently been considering the possibility of a pilot chute in tow, mainly being caused by a pin locking under a pin protector flap and thought of some possible solutions.

Has anyone ever experimented with shorter pins or for that matter why do we currently have a standard pin length? Was this just copied from skydiving where a pin lock cannot occur in the same manner as a base container.

Also has anyone considered making closing loops from break cord. You would obviously need to know what force different sized pilot chutes can create at different speeds and know if this is greater than the force required to close the container and if so use break cord with a strength somewhere in between.

I welcome any feedback on whether people think either ideas would be feasable and any potential downsides apart from the obvious need to relace closing loops more frequently.

I would worry about the friction of break cord as a closing loop material. Something more "slippery" with an equally low breaking strength might be an idea. I'm not sure that a low breaking strength closing loop is ideal though--there is certainly such a thing as a loop that's too weak.

Which "standard" pin length are you using? I've seen different length pins from different manufacturers at different times.



What's your eventual aim? Reduce the chance of a container lock?

Many years ago the world's leading BASE jumper (a guy with the oddly nordic sounding name of Boenish) actually contracted with a leading (skydiving) parachute rigger named Jim Handbury to create a rig that would have no chance of container lock, specifically for BASE jumping. The results were fairly impressive, in terms of creating a container with very minimal chance of container lock (basically zero chance if properly packed and closed). I wonder if looking at some of that research would be a place to start, if your goal is to eliminate container locks.

The tension in the loop is ~half the bridle tension. MIL-T-5661 break tape is rated for 80 lb min breaking strength. With a PC choice appropriate for a given deployment air speed, you would not achieve enough bridle tension to break the tape

Moe V. showed me a rig when I was down in FL that instead of pins had cut away cable cut to about 3-4 inches attached to the same spots the pins would be. Orientation didn't seem to matter for extraction and there was in his opinion 0 chance for a container lock. I liked the idea for sure but haven't had a chance to build myself one yet. Busy with other side projects.

(And he probably claimed to have invented it, but) this is a version of the old 'Polish Pin'. When skydiving gear first went to hand deploy, before curved pins were developed, either a straight pin or even a bight of bridle was used through the closing loop, which sometimes resulted in a pilot chute in tow. Someone came up with the cutaway cable pin with a bungee closing loop and it worked pretty well. Moe's probably right, it probably would help with this problem.


Regarding Tom's post:




Ahh, the original velcro shrivel-flap containers. They worked great, and were prevalent for a long time (are they still?), but people worried whether they might blow open at terminal. If I remember correctly, I believe the aforementioned Moe V. made some airplane jumps with one (shhhh!) and went inverted, head down, sat, rolled, twisted, and otherwise TRIED to make it open prematurely, but was unable to do so. Replace the velcro often!.

I know a bunch of Russian guys who were jumping that sort of thing (yellow cables replacing closing pins) around 2000.

That sounds like a good idea. Do you know how he attached the cable to the bridle?

Cables replacing closing loops or pins? Im not sure how using it to replace the closing loops would help.

You can just swage the cable together--like on a cutaway handle.

Sorry. That was a mental/typographical error.

Yellow cables replacing the pins.

I like this idea. I might play around with it and see how it looks

Nothing like re-inventing the wheel

Edit: I remember seeing it in skydiving in the early 2000s from my recollection. Strong still uses the system on their drogue release systems.

I was going to say that about the flex pin that strong use. The question is why do we use pins, i can understand in skydiving because it likely lasts longer and doesnt have the same potential to lock on a closing flap however perhaps in base a cable is better, my biggest concern would be the potential for it to pull through the gromet.

Here's what it looks like on an Ava Sport Acro BASE paragliding harness.

Some of us old guys did hundreds or thousands
of tandem jumps using gear that was closed
vis-a-vis cables: Vector 2, Eclipse, & Strong.

I have jumped rigs with velcro, 1 pin, 2 pins,
3 pins, cables, etc. They ALL work fine IF
you use them as directed and intended.

Meaning a butter knife is an imperfect screw
driver, a rock is a terrible hammer, and so on.

Maybe a little off-subject, but I remember reading a few threads on here, dz.com, and blinc, regarding a closing loop cutaway system with housings going to the top and bottom flaps. Has anyone in the last 15 years or whatever it's been since then played around with something like that?

Seems like there are a limited number of cases where something like that would be effective, but in a situation where you're three seconds from towing a PC to impact, seems like it'd be pretty fucking cool to have something like that.

I know two riggers (one in California and one in Europe) who independently created a system with closing loops that would actually be "cut away" from the system themselves, opening the pack tray in the event of a container lock.

Their systems are a lot better version of the old systems (which required you to manually activate the cutaway) because it basically works automatically if there is excessive pressure.

I think it's too complicated to really put into general service though. It involves a double headed closing loop that actually joins the two loops of a two pin system.

Firstly, I couldn't imagine a scenario that could cause the necessary forces to pull a cable through a side flap grommet. It's rare to see even on risers where they get hammered by opening shock.
Secondly, Cables also have know failure modes too. like the coatings being stripped off the cable and getting jammed up in the closing or locking loops.

I've always thought the Apex TLs would be the perfect rig for this. With both loops anchored to floor plates everything could be neatly concealed in the back pad. Of course then you would need to have one of those canopies with the hole sewed through the tail.

The ones I've seen built hide the loop/band inside the side flap, where it extends over for the grommets. There's basically a hidden "pocket" inside it that houses them. It's not necessary to make the system operate though--it's just cosmetic.

its not the pins beeing the problem, its comes down to container geometry. and i wouldnt really say its a overly serious problem in the first place once you know what you have to look out for.

slider down -> open the pin protektor flap and this is not going to be ANY issues anymore with most container designs, and the ones remaining are fixable by just standing up the pins.
slider up -> neither pin lenght nor containers geometry is a problem the problem here.
what youre left with is the chance of putting a bridle knot around your PC, or forgetting to put a PC on the bridle in the first place.


yes, multiple jumpers i know of, including me.


this.

Is that me that you talking about ? ;)
Anyway here is the system (in attach).

To Explain it is a pocket where center of loop is tied (with reserve seal thread) to small loop. Loop is inserted into a pocket and closed via small loop though center grommet. Whole thing is connected to bridle attachment point.
If there is a pinlock on one pin and second pin is pulling, break thread will break and it will release pinlocked pin.

I was planning to use it with yellow (lulon cutaway) cable, but in way that bridle pulls on both pins (check second attachment).

Didn't jump it yet.

"a long time ago in a galaxy far far away"

http://acrobatbase.ru/...uktsiya/p1010051.jpg