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The Z-hills Double Fatal Speculation Thread

 

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airtwardo  (D License)

Apr 3, 2013, 8:35 AM
Post #126 of 157 (2278 views)
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Re: [JohnSherman] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
Same time longer distance/altitude due to speed.

Thanks John, that confirms what I was trying to point out in one of these threads where I listed distance covered at various freefall speeds.

Via PM ~ I got some comments 'correcting' my assertion...it's seems there are those who believe that double the freefall speed = 1/2 the opening distance.

"...the parachute opens faster because you're going faster" is somewhat flawed logic regarding this type of scenario- IMO.


JohnSherman  (D 2105)

Apr 3, 2013, 11:32 AM
Post #127 of 157 (2184 views)
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Re: [airtwardo] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

You know, some things do happen faster,but the overall result is more distance due to more speed.
I find that to deploy a canopy in 300 feet at terminal you had better be able to do it in 200 feet at cutaway speeds. Apply that to what we are seeing. Unsure

John


airtwardo  (D License)

Apr 3, 2013, 12:26 PM
Post #128 of 157 (2141 views)
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Re: [JohnSherman] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
You know, some things do happen faster,but the overall result is more distance due to more speed.
I find that to deploy a canopy in 300 feet at terminal you had better be able to do it in 200 feet at cutaway speeds. Apply that to what we are seeing. Unsure

John


Understood.

I get the feeling some believe it's a more exact science in regard to the 'twice the speed = 1/2 the time & distance' that just isn't something to bet your life on.


Rstanley0312  (D 31900)

Apr 8, 2013, 1:54 PM
Post #129 of 157 (1537 views)
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Re: [airtwardo] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
In reply to:
You know, some things do happen faster,but the overall result is more distance due to more speed.
I find that to deploy a canopy in 300 feet at terminal you had better be able to do it in 200 feet at cutaway speeds. Apply that to what we are seeing. Unsure

John


Not directed at you Twardo just a question.... I have read a lot of why "SOS set ups are bad". I just wonder if what I hae heard holds any water. Unless you are doing CRW, or possibly camera.... why not an SOS. I know some are going to slam this but I know many very experienced skydivers that believe it is the only way to go. After all.... if you are jumping a skyhook or an rsl aren;t you really just trying to replicate what an SOS accomplishes except in a more complicated manner? I would love to hear some thoughts on this... perhaps it should go in to gear and rigging.....

Rob

Understood.

I get the feeling some believe it's a more exact science in regard to the 'twice the speed = 1/2 the time & distance' that just isn't something to bet your life on.


Premier billvon  (D 16479)
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Apr 8, 2013, 1:56 PM
Post #130 of 157 (1534 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

>why not an SOS.

There are definitely pros and cons. The one negative that bothers me is that riser twist that traps the cutaway cables, or causes even a hard pull, means you can't open your reserve without using a backup means (i.e. pulling directly on the RSL shackle or something.) However that's a very unusual problem, especially with hard riser channels.


Rstanley0312  (D 31900)

Apr 8, 2013, 2:10 PM
Post #131 of 157 (1524 views)
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Re: [billvon] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
>why not an SOS.

There are definitely pros and cons. The one negative that bothers me is that riser twist that traps the cutaway cables, or causes even a hard pull, means you can't open your reserve without using a backup means (i.e. pulling directly on the RSL shackle or something.) However that's a very unusual problem, especially with hard riser channels.

That is what I was going to ask... with hard riser channels do you think that is still possible? That would take a lot of force but in our sport a lot of force does happen.


Scrumpot  (D License)

Apr 9, 2013, 8:35 AM
Post #132 of 157 (1349 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

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That is what I was going to ask... with hard riser channels do you think that is still possible? That would take a lot of force but in our sport a lot of force does happen.

Yes, that is still possible. But much more likely and prevalent from poorly maintained cutaway cables and systems over-all, actually. Not just specifically pertaining to hard-housings preventing cable-pinch from linetwists, which is here - what you are referring to. I've unfortunately seen many more hard (cutaway) pulls, occur caused by something as simple as dirty, poorly maintained cables and systems actually. - Regardless of which system they happen to be.


JohnSherman  (D 2105)

Apr 9, 2013, 9:00 AM
Post #133 of 157 (1330 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

Quote:
The one negative that bothers me is that riser twist that traps the cutaway cables, or causes even a hard pull,

This is a fallacy: Twisted risers donít trap the cables in the cloth riser channels if the yellow cable is properly lubricated or if you have a red cable. Hard housing donít help.

Proof: In a suspended harness lubricate your yellow cable and route it as normal but by pass the riser locking loops. Use a temporary cable for the riser loops. Load the harness with an extra person hanging on each side (3 bloke test) and twist it upto the 3 rings. Have the person in the harness pull the release cable. Now pull each of the individual riser cables and compare the difference. You may repeat the test with hard housings but you will not need to.


(This post was edited by JohnSherman on Apr 9, 2013, 9:04 AM)


Rstanley0312  (D 31900)

Apr 9, 2013, 9:37 AM
Post #134 of 157 (1313 views)
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Re: [JohnSherman] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
Quote:
The one negative that bothers me is that riser twist that traps the cutaway cables, or causes even a hard pull,

This is a fallacy: Twisted risers donít trap the cables in the cloth riser channels if the yellow cable is properly lubricated or if you have a red cable. Hard housing donít help.

Proof: In a suspended harness lubricate your yellow cable and route it as normal but by pass the riser locking loops. Use a temporary cable for the riser loops. Load the harness with an extra person hanging on each side (3 bloke test) and twist it upto the 3 rings. Have the person in the harness pull the release cable. Now pull each of the individual riser cables and compare the difference. You may repeat the test with hard housings but you will not need to.

Okay.... with all of that said.... why not an SOS system?


Premier billvon  (D 16479)
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Apr 9, 2013, 9:46 AM
Post #135 of 157 (1302 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

>That is what I was going to ask... with hard riser channels do you think that is still possible?

Sure; you can get a kink in the cable (i.e. "cable suck") or a pebble in the harness housing. Odds of them are low which is why I don't think it's a big deal.


topdocker  (D 12018)

Apr 9, 2013, 9:50 AM
Post #136 of 157 (1299 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
In reply to:
Quote:
The one negative that bothers me is that riser twist that traps the cutaway cables, or causes even a hard pull,

This is a fallacy: Twisted risers donít trap the cables in the cloth riser channels if the yellow cable is properly lubricated or if you have a red cable. Hard housing donít help.

Proof: In a suspended harness lubricate your yellow cable and route it as normal but by pass the riser locking loops. Use a temporary cable for the riser loops. Load the harness with an extra person hanging on each side (3 bloke test) and twist it upto the 3 rings. Have the person in the harness pull the release cable. Now pull each of the individual riser cables and compare the difference. You may repeat the test with hard housings but you will not need to.

Okay.... with all of that said.... why not an SOS system?

Does suck to have an SOS in winds. Can't chop the canopy if you are getting drug around the landing area....

It has its merits, but it just seems safer to be able to activate the reserve independently.

top


airtwardo  (D License)

Apr 9, 2013, 9:52 AM
Post #137 of 157 (1297 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

Okay.... with all of that said.... why not an SOS system?

In reply to:

One example- in the popular video going around in which a jumpers cutaway pud is inadvertently pulled on exit and handed back to him...

'what if' that happened during a squirrely exit and the reserve somehow horseshoed or otherwise malfunctioned? Like a late diver going through the unexpected reserve and shredding it...

You would have a packed up main that is of absolutely no good to you.


(This post was edited by airtwardo on Apr 9, 2013, 9:56 AM)


Rstanley0312  (D 31900)

Apr 9, 2013, 10:07 AM
Post #138 of 157 (1270 views)
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Re: [airtwardo] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
Okay.... with all of that said.... why not an SOS system?

In reply to:

One example- in the popular video going around in which a jumpers cutaway pud is inadvertently pulled on exit and handed back to him...

'what if' that happened during a squirrely exit and the reserve somehow horseshoed or otherwise malfunctioned? Like a late diver going through the unexpected reserve and shredding it...

You would have a packed up main that is of absolutely no good to you.

That is a valid point but there is a very small chance of that happening. I do see your point though.


Rstanley0312  (D 31900)

Apr 9, 2013, 10:08 AM
Post #139 of 157 (1265 views)
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Re: [topdocker] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
In reply to:
In reply to:
Quote:
The one negative that bothers me is that riser twist that traps the cutaway cables, or causes even a hard pull,

This is a fallacy: Twisted risers donít trap the cables in the cloth riser channels if the yellow cable is properly lubricated or if you have a red cable. Hard housing donít help.

Proof: In a suspended harness lubricate your yellow cable and route it as normal but by pass the riser locking loops. Use a temporary cable for the riser loops. Load the harness with an extra person hanging on each side (3 bloke test) and twist it upto the 3 rings. Have the person in the harness pull the release cable. Now pull each of the individual riser cables and compare the difference. You may repeat the test with hard housings but you will not need to.

Okay.... with all of that said.... why not an SOS system?

Does suck to have an SOS in winds. Can't chop the canopy if you are getting drug around the landing area....

It has its merits, but it just seems safer to be able to activate the reserve independently.

top

I am not sure if it does seem safer. Easy fix to your situation.... do not jump in those high of winds. I personally do not right now even with my two handle system.


airtwardo  (D License)

Apr 9, 2013, 12:26 PM
Post #140 of 157 (1177 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
In reply to:
Okay.... with all of that said.... why not an SOS system?

In reply to:

One example- in the popular video going around in which a jumpers cutaway pud is inadvertently pulled on exit and handed back to him...

'what if' that happened during a squirrely exit and the reserve somehow horseshoed or otherwise malfunctioned? Like a late diver going through the unexpected reserve and shredding it...

You would have a packed up main that is of absolutely no good to you.

That is a valid point but there is a very small chance of that happening. I do see your point though.

Small chance maybe...IF it did though, there would be zero chance of it ever happening to ya AGAIN!


(This post was edited by airtwardo on Apr 9, 2013, 12:29 PM)


popsjumper  (D 999999999)

Apr 9, 2013, 12:43 PM
Post #141 of 157 (1159 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
Easy fix to your situation.... do not jump in those high of winds. I personally do not right now even with my two handle system.

Never had wind speed or direction or both change on ya', eh? Hang in there...it'll happen.


Premier billvon  (D 16479)
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Apr 9, 2013, 12:59 PM
Post #142 of 157 (1145 views)
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Re: [topdocker] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

>Can't chop the canopy if you are getting drug around the landing area....

Sure you can; the reserve will then open and you'll need a repack, but you won't get dragged. (Same problem with an RSL.)


BMFin

Apr 9, 2013, 2:21 PM
Post #143 of 157 (1097 views)
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Re: [billvon] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

http://iloveskydiving.org/...nction-cant-cutaway/

If im not mistaken this guy would have been in much more trouble if he had SOS system.


normiss  (D 28356)

Apr 9, 2013, 8:49 PM
Post #144 of 157 (1016 views)
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Re: [BMFin] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

Or wearing the Death Suit model of wingsuit like the recent fatality.


robinheid  (D 5533)

Apr 9, 2013, 10:28 PM
Post #145 of 157 (991 views)
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Re: [billvon] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
>Can't chop the canopy if you are getting drug around the landing area....

Sure you can; the reserve will then open and you'll need a repack, but you won't get dragged. (Same problem with an RSL.)


Sorry, no... not the same problem.

You can disconnect an RSL when you see that the winds might require a cutaway when you land, but unless they've changed the design since I last saw one, you can't disconnect the cutaway and reserve pull functions on an SOS.

Cool
44


(This post was edited by robinheid on Apr 9, 2013, 10:31 PM)


Rstanley0312  (D 31900)

Apr 10, 2013, 6:27 AM
Post #146 of 157 (933 views)
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Re: [popsjumper] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
In reply to:
Easy fix to your situation.... do not jump in those high of winds. I personally do not right now even with my two handle system.

Never had wind speed or direction or both change on ya', eh? Hang in there...it'll happen.

Pops... ya I have but not to the speeds that it drags me around. Maybe a little pull but nothing really that bad. I'm sure it will happen eventually. I have really een thinking about this because of some very experienced jumpers that use an SOS system still. Everything that I have ever heard negative about them is either a rare circumstance which lets be honest.... those can occur on any piece of equipment or when it gets down to it... the jumper does not look cool with an SOS Tongue


Rstanley0312  (D 31900)

Apr 10, 2013, 6:31 AM
Post #147 of 157 (927 views)
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Re: [airtwardo] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
In reply to:
In reply to:
Okay.... with all of that said.... why not an SOS system?

In reply to:

One example- in the popular video going around in which a jumpers cutaway pud is inadvertently pulled on exit and handed back to him...

'what if' that happened during a squirrely exit and the reserve somehow horseshoed or otherwise malfunctioned? Like a late diver going through the unexpected reserve and shredding it...

You would have a packed up main that is of absolutely no good to you.

That is a valid point but there is a very small chance of that happening. I do see your point though.

Small chance maybe...IF it did though, there would be zero chance of it ever happening to ya AGAIN!

Twardo..... once again VERY valid point. Same thing could be said of many pieces of equipment though... right? AAD for insance.... door opens, pressure change, you are by the door.... reserve comes out and you hit the tail. Very rare occurance but it has happened. Very likely if it happened to you it woud never happen again. I am not for or against an SOS I am just thinking through it all and getting opinions. I appreciate yours and everyone else's.


FB1609  (C 1409)

Apr 10, 2013, 8:06 AM
Post #148 of 157 (873 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

if your on the gound getting dragged you can pull an SOS just a bit for cutaway only with most systems and a couple of practices


(This post was edited by FB1609 on Apr 10, 2013, 8:06 AM)


Rstanley0312  (D 31900)

Apr 10, 2013, 8:13 AM
Post #149 of 157 (866 views)
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Re: [FB1609] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

In reply to:
if your on the gound getting dragged you can pull an SOS just a bit for cutaway only with most systems and a couple of practices

I was told the same thing.... you can stage your pull.


JohnSherman  (D 2105)

Apr 10, 2013, 8:30 AM
Post #150 of 157 (847 views)
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Re: [Rstanley0312] The Z-hills Double Fatal Speculation Thread [In reply to] Can't Post

Quote:
Okay.... with all of that said.... why not an SOS system?

The only problem, other than those already mentioned, with the SOS (SINGLE Handle Operating System), is that is takes 2 hands to operate it.
One for the initial pull and the other to grab the cable half way from the handle and finish the pull. The stroke is too long for your arm. This is inherrent in the design because of the required cable lengths.
The configuration must allow for the release of the risers before the reserve is released. Some long armed folks can reach, in one stroke, on some rigs, but not all.


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