Forums: Skydiving: Safety and Training:
Tighter closing loop

 


skreamer

Jun 11, 2001, 2:16 AM
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Tighter closing loop Can't Post

In light of this latest fatality, how do you know when your closing loop is tight enough? Also, I was told to insert the pin so that it was pointing up - apparently this protects it better from being jostled loose in the plane - is this a good idea? Now I really appreciate why a freefly rig with secure velcro-less flaps is a MUST for going head down (please note that is a general observation I don't know what rig the man who died was wearing).

I will be trying freeflying in the near future, what other advice can you experienced guys give me, re. freeflying safely?

I feel for this guy's friends and family - by all accounts he was doing all he could to resolve the problem all the way in.

Will



Geoff

Jun 11, 2001, 5:59 AM
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In reply to:
how do you know when your closing loop is tight enough?
The grommets should be touching. The flaps should hardly 'relax' and spread apart at all (a couple of millimetres at most) when you take the pressure off your pull-up cord.

Pin pointing up is a good idea - it's less likely to be knocked when moving around the plane or sitting on the floor.

I've seen a few freefliers with their main pin replaced by a short length (few inches) of doubled teflon cable, which seems a good idea, is much more secure, and whose main disadvantage seems to be that closing loops wear more quickly.

A good secure rig with an upwards-pointing main flap (e.g. Vector, Mirage, Voodoo, Wings, etc) is a very good idea. Very personal opinion, but I don't consider any rig with a down-pointing main flap (Javelin, Dolphin, Talon, Reflex, Atom) to be ideal for freeflying.

Geoff



PalmettoTiger

Jun 11, 2001, 6:19 AM
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In reply to:
A good secure rig with an upwards-pointing main flap (e.g. Vector, Mirage, Voodoo, Wings, etc) is a very good idea. Very personal opinion, but I don't consider any rig with a down-pointing main flap (Javelin, Dolphin, Talon, Reflex, Atom) to be ideal for freeflying.
I've heard a few people mention this before, but never really understood it. Could someone explain it to me?

Blues, Squares,
PTiger

*insert sub-100 character sig here*


Geoff

Jun 11, 2001, 7:09 AM
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OK - some disadvantages of the down-pointing flap.

(1) The fit of the flap depends on the precise shape of the pack job.
(2) The flow of air tends to dislodge the flap when sitting or standing
(3) The flap can easily be knocked open when sitting on the floor, on other people's feet, or by window edges in planes with benches.
(4) The 'tongue' (the part of the flap that tucks back under) can bend and gradually become deformed, causing the fit to get worse and worse.
(5) you can't solve the problem with a longer 'tongue' on the flap because it would touch the closing loop.
(6) in general, these designs are very sensitive to the geometry of the container - minor stretching as the rig wears can make the flap fit worse.

That's just off the top of my head.

Plus I've seen many loose downward-pointing flaps in freefall (and in several magazine pictures), and never seen a loose upward flap.

I notice that Parachutes de France is modifying the new Atom (called the Atom Legend) to replace the flap with an upwards design, as did the Relative Workshop for the Vector III compared to the Vector II.

Frankly I was surprised that Sunpath didn't do something similar with the Odyssey.

Geoff





PalmettoTiger

Jun 11, 2001, 9:42 AM
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Thanks for the info - that all makes sense as I visualize it.

Blues, Squares,
PTiger

*insert sub-100 character sig here*


riggerrob  (D 14840)

Jun 11, 2001, 10:27 AM
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How do you know when your loop - on a throw-out - is too tight?
1. You can't close the rig.
2. You can pick the rig up by the main bridle.
The loop is too tight on a pull-out if you struggle at pull time. Even a minor struggle will put you one shoulder low which can result in line twists, etc.



Aviatrr  (D 27349)

Jun 11, 2001, 8:35 PM
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In reply to:
how do you know when your closing loop is tight enough?
Chances are if the closing loop is too tight, you will not be able to close the container. Try this. Adjust your closing loop so that it is so tight that you can BARELY close the container using all your strength. Place the rig on the ground(or even better, on somebody else laying face down on the floor) and pull on the bridle as if your PC were inflated behind you pulling on the pin. How easily does the pin come out? If I remember correctly, most pilot chutes exert about 100-120 pounds of pull force at 110-120mph. Add to that the fact that it will not be pulling on your pin the whole time - but will be building up speed and force for about 6-7 feet(the length of your bridle) - then exerting all that force for a split second.

If you really want to know how much force a PC exerts, try this. First, get a harness and anchor yourself into the bed of a truck. Get a PC the same as the one in your rig. Get a scale similar to a fish scale, but with a much higher weight range. Attach PC to the end, and have somebody start driving. When you reach about 110-120mph - that's your PC's long term force in freefall. Oh, and if you do try this experiment, please have somebody video tape it. Smile

In reply to:
Also, I was told to insert the pin so that it was pointing up - apparently this protects it better from being jostled loose in the plane - is this a good idea?
I, personally, believe this is the best way to set your pin - unless the manufacturer states different(which I have never heard of). If you are leaning back on your rig in the plane, chances are you will push the pin up if it comes into contact with anything.

In reply to:
I will be trying freeflying in the near future, what other advice can you experienced guys give me, re. freeflying safely?
I can think of lots of little things.

Give more time than normal between the group ahead of you and yourself. Most new freeflyers are all over the sky. You don't want to end up unintentionally tracking over the group prior to you and have them deploy under you.

Make sure your rig is suitable for freeflying. Secure riser covers, secure flaps, etc.. Check with your local rigger on this one.

Don't jump with other novice freeflyers. The speeds you can reach - both vertical and horizontal - are incredible. If somebody flies over you, and you cork, it could mean major injuries or death for both. Do solo jumps until you are comfortable with(and good at) the basic positions - i.e. able to stay in a sit as long as you want.

Be VERY vigilant at altitude awareness. Your altitude will go away very quickly in a fast freefly position. I have had as short as 40-45 second freefall times from 13,500 to 2500 on fast head down dives.

Talk with some of your local, experienced freeflyers. Not only can they help you with some basic freeflying skills, they can help you stay safe - and keep everybody else in the air safer. Most of all - have fun. Freeflying is awesome.

Also, you may want to cross-post this question in the gear and rigging thread. Alan can probably give you a better idea of forces exerted by a PC, and how tight is too tight.

Mike




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