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Static Line twists / First freefall

 

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14000andfalling  (Student)

Mar 10, 2007, 2:52 PM
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Static Line twists / First freefall Can't Post

From watching a few videos and reading a few posts and articles on Static Line jumps, I was wondering why Line Twists are more common on the SL as oppose to Freefall from a higher altitude?
I guess that your body position on exit plays a great part, but surely that applies in all situations and not just SL?

Also, i have noticed that a few people have problems with their first freefall/hop n pop deployment on the SL course...is this again because of the slower rate of descent?
I'm just curious as to why the SL students need to make the Hop n' Pop, 5's, 10's, 15's and 20's as opposed to going straight up to altitude as with the AFF course?
Obviously it's cheaper because you don't have 2 instructors with you, but why the gradual steps up in Altitude?

Sorry if these seem dumb questions but i'm still a newb (2 weeks to go!!Smile) and am just trying to clear up a few things in my head.


Andy_Copland  (A 105852)

Mar 10, 2007, 4:52 PM
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Re: [14000andfalling] Static Line twists / First freefall [In reply to] Can't Post

If the guys here with the experience care to correct me i would guess that it has alot to do with aircraft too.

I wonder if the D-Bag would spin up more with the prop wash with certain aircraft etc?

All that forward momentum plus prop wash, i dont know. CrazyLaugh


aguila  (B 1009)

Mar 10, 2007, 5:11 PM
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Re: [14000andfalling] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
I was wondering why Line Twists are more common on the SL as oppose to Freefall from a higher altitude?
I guess that your body position on exit plays a great part, but surely that applies in all situations and not just SL?

Welcome to the sport!

It is because of wrong body position. You do not have time to correct it. On AFF you have more time to correct it. I think AFF is safer.


sundevil777  (D License)

Mar 10, 2007, 8:33 PM
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Re: [14000andfalling] Static Line twists / First freefall [In reply to] Can't Post

Besides the greater likelihood of poor body position reasons, most static liners are done with the direct-bag method of deployment, where the main d-bag is attached to the static line, instead of the static line just pulling out and releasing a pilot chute. So, the lines and canopy are pulled out of the bag forming a curved shape to the falling jumper until they clear the bag, that then whips back into the relative wind to finish inflation. I suspect that gives a possibility for some line twists. The big advantage of the direct bag is that it gets everything pulled out a lot more reliably for students that have poor body position/tumbling than a spring loaded PC can. It used to be that a break cord of about 50 pounds would attach the PC to the static line - 'pilot chute assist' and that was better than the static line just opening the container and leaving the rest to a PC.


dragon2  (D 101989)

Mar 10, 2007, 10:39 PM
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
In reply to:
I was wondering why Line Twists are more common on the SL as oppose to Freefall from a higher altitude?
I guess that your body position on exit plays a great part, but surely that applies in all situations and not just SL?

Welcome to the sport!

It is because of wrong body position. You do not have time to correct it. On AFF you have more time to correct it. I think AFF is safer.

Please don't answer if you do not have a clue what you're talking about.

With direct-bag SL you have a big chance of linetwists because of the deployment method. One in 3 jumps or so you will get linetwists even with great body position. No biggie, you're using a big docile canopy and I think it's actually good practice; seen a few AFF people who have no clue how to get out of simple linetwists and/or panic and/or cutaway needlessly.

SL and AFF both have their strong points and their specific "dangers". There are a gazillion threads about which is better already. Both will get you on your way to your A so who cares.


DougH  (D License)

Mar 11, 2007, 6:28 AM
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
I think AFF is safer.

Yes, because you're the expert on saftey!!! Crazy


Orange1  (B 2638)

Mar 11, 2007, 8:17 AM
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Re: [sundevil777] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
So, the lines and canopy are pulled out of the bag forming a curved shape to the falling jumper until they clear the bag, that then whips back into the relative wind to finish inflation. I suspect that gives a possibility for some line twists. .

This is basically what was explained to me. I had line twists on about half my SL jumps, even those with perfect body position. When I did my first freefall I could feel the absence of "being jerked" and opened perfectly on heading without twists.


Andy9o8  (D License)

Mar 11, 2007, 9:49 AM
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

In the S/L method you're not cleared for your first freefall (a hop & pop) until you've have a minimum of 5 S/L jumps, at least 3 of which include practice pulls of a dummy ripcord/hackey. Unlike AFF, if the S/L-deployed student freezes and goes fetal, his canopy will still deploy on time regardless of whether he pulls or not. A S/L-deployed student cannot break away from - and have to be chased by - his instructors - potentially a very dangerous maneuver for both student and instructors. A S/L-deployed student, say on his 1st or 2nd jump where sensory overload brain-lock is not uncommon, will not have to be deployed out by his instructor (or an AAD) to get a canopy out to save his life. A S/L student will not whip around and kick his instructor in the head, or try to bear-hug an instructor trying to re-stabilize him.

For extra currency's sake, that first freefall jump must be made on the same day as the last S/L. From there, you progress doing 2 or 3 jumps at 5 second delays, then 10 seconds, then 15 or 20 seconds, etc. On S/L progression, you probably won't be at terminal velocity at deployment altitude (correlate with available time to perform EP's) until you've had at least 10 or 15 jumps under your belt. The chances that a S/L progression student on an early freefall, even if he goes unstable, will just freeze out of panic and pull nothing has historically been shown to be pretty rare. Why? Because by the time he does even his first freefall, he's already had a minimum of 5 skydives under his belt, and that does wonders for reducing sensory overload (as does the requirement to make the 1st FF the same day as the last S/L). The S/L progression method is all about graduality, and that graduality translates into safety.

Yes, square canopies are more sensitive on deployment to body and line position than simple military round canopies are. So since the sport transitioned from using simple round canopies to square canopies for S/L students, you do get more line twists, etc. on S/L canopies than used to be the case. Yes, AFF gets the student more freefall skills in fewer jumps. But aside from that, saying that AFF is safer than S/L is simply incorrect.


Andy9o8  (D License)

Mar 11, 2007, 10:18 AM
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Re: [14000andfalling] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
I'm just curious as to why the SL students need to make the Hop n' Pop, 5's, 10's, 15's and 20's as opposed to going straight up to altitude as with the AFF course?
Obviously it's cheaper because you don't have 2 instructors with you, but why the gradual steps up in Altitude?

The reason for the gradual steps is that it's a safe way for the student to become acclimated with freefall without the need for an instructor to be right along-side him to assure his safety. You don't get to progress to the next level until you've proven the ability do fall stable and deploy on time at the current level. The corollary is that if you've done well on 2 or 3 5-second delays, it's presumed you're safely ready to move on to 10-second delays. It worked for many thousands of jumpers before AFF came out.

So - why not just put a new student out at full altitude for his first freefall after S/L? Because it's not safe (enough) to do that with a 1st or 2nd freefall student without an instructor jumping along-side him; and if he has an instructor with him, well, that's AFF. Which brings me to my next point - hybrid training methods.

As a former S/L progression student myself, I think one thing that AFF does better than S/L is that if the S/L program student has stability problems on his 5 & 10 second jumps, he's got nobody in freefall along with him to physically assist him to a stable position, and so he can wind up getting "stuck" on 5-second delays, and then quit out of frustration. For those types of students, switching over to a few AFF-style jumps with an instructor would be a good thing.

Personally, having seen both methods when they were commonplace, I think the best method is a hybrid method that is done at a few DZ's. They start out with an introductory tandem to get past the first-jump shock - where the instructor is totally responsible for exit, deployment, EP's and landing; then a couple of S/L jumps where (aside from EP awareness) all they have to think about is a good exit and canopy control/landing, then on to a few AFF jumps to learn freefall performance tasks. I wish more DZs would offer this.


(This post was edited by Andy9o8 on Mar 11, 2007, 10:23 AM)


skydude2000  (B 5843)

Mar 11, 2007, 11:02 AM
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Re: [14000andfalling] Static Line twists / First freefall [In reply to] Can't Post

I think the main reason the S/L progression is so gradual, is so that your instructors can diagnose any changes in your stability or body position. I know when I started, I was fine up to 10 second delays, but when I moved up to 15 sd, things started going wonky. So if I had just been stable for 10 seconds, and they said 'ok, you're fine' and then went up to 9,500 feet and did a 30 second delay, I could have gotten into some real trouble. I think it's much easier to fix a stability problem early on, before it gets to the point where the student becomes out of control. As for the reason for line twists on a direct-bag deployment, I'm not sure. I only know one of the clubs I jumped at, switched to D-bag s/l from IAD, because they'd had a number of malfunctions under IAD, and they decided line-twists on student canopies are easier to deal with than malfunctions.


aguila  (B 1009)

Mar 11, 2007, 11:04 AM
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Re: [DougH] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
In reply to:
I think AFF is safer.

Yes, because you're the expert on saftey!!! Crazy

Oops!. It seems someone finally explained my joke to you Wink http://www.dropzone.com/...post=2677044#2677044


JohnMitchell  (D 6462)

Mar 11, 2007, 11:14 AM
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
It is because of wrong body position. You do not have time to correct it. On AFF you have more time to correct it. I think AFF is safer.
No, I think it's because most static line jumps are made from the strut of a C-182. The static line's direction of pull is at an angle to the student, instead of straight up. This often imparts a spin to the bag, which will result in line twists. I've jumpmastered many hundreds of SL students. I've this happen a lot, even with great exits and arches.

Is AFF safer than SL? Both seem pretty safe anymore. That's a good thing. Smile


aguila  (B 1009)

Mar 11, 2007, 11:19 AM
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Re: [dragon2] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
In reply to:
In reply to:
I was wondering why Line Twists are more common on the SL as oppose to Freefall from a higher altitude?
I guess that your body position on exit plays a great part, but surely that applies in all situations and not just SL?

Welcome to the sport!

It is because of wrong body position. You do not have time to correct it. On AFF you have more time to correct it. I think AFF is safer.

Please don't answer if you do not have a clue what you're talking about.

With direct-bag SL you have a big chance of linetwists because of the deployment method. One in 3 jumps or so you will get linetwists even with great body position. No biggie, you're using a big docile canopy and I think it's actually good practice; seen a few AFF people who have no clue how to get out of simple linetwists and/or panic and/or cutaway needlessly.

SL and AFF both have their strong points and their specific "dangers". There are a gazillion threads about which is better already. Both will get you on your way to your A so who cares.

=I am not talking about Hop n' Pop, 5's, 10's, 15's and 20's. I am talking about body position and line twists.

Please, select the one that applies:

a- You are Dough's friend
b- You do not have any idea about line twists and body position
c- You think you are a skydive god
d- All of them


14000andfalling  (Student)

Mar 11, 2007, 11:22 AM
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Re: [JohnMitchell] Static Line twists / First freefall [In reply to] Can't Post

Some really good answers there people, thank you very much.


aguila  (B 1009)

Mar 11, 2007, 11:52 AM
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Re: [JohnMitchell] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
In reply to:
It is because of wrong body position. You do not have time to correct it. On AFF you have more time to correct it. I think AFF is safer.
No, I think it's because most static line jumps are made from the strut of a C-182. The static line's direction of pull is at an angle to the student, instead of straight up. This often imparts a spin to the bag, which will result in line twists. I've jumpmastered many hundreds of SL students. I've this happen a lot, even with great exits and arches.

Is AFF safer than SL? Both seem pretty safe anymore. That's a good thing. Smile

I just talk from my experience. I jumped 23 SL from different airplanes (no 182) and got line twists until I finally got a good body position and stable exits. They always taped my exits. The angle you mention surely has something to do but a good body position helps.

Why do I think AFF is safer? Because I have seen -and had more incidents jumping SL than AFF. ( students' incidents and reserves)

PS This is for DougH & friends: 23 SL jumps! Do not miss this Cool If you miss this I am going to miss you Tongue


Premier billvon  (D 16479)
Moderator
Mar 11, 2007, 12:25 PM
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Re: [JohnMitchell] Static Line twists / First freefall [In reply to] Can't Post

>The static line's direction of pull is at an angle to the student, instead of straight up.

I would add that the system makes a difference. PC assist is more similar to IAD, and results in fewer line twists. However, direct bag pulls the parachute INTO the relative wind before it releases it, leading to some mighty odd openings.


dragon2  (D 101989)

Mar 11, 2007, 1:53 PM
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

Are you for real?

FYI, I do not know anyone named Doug, I went through SL as did most at my DZ, and the skygod would be a skygoddess Laugh


koppel  (F License)

Mar 11, 2007, 4:30 PM
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Re: [Andy9o8] Static Line twists / First freefall [In reply to] Can't Post

having gone through S/L myself (with various issues like spinning) and now being rated for TM / SL / AFF I am in complete agreement with you.

One of the things that I have noticed (put those flames away boys) is that S/L students tend to be more independent and self-sufficient over their AFF counterparts in the early days off student status. I think by the time that they finish their B's at around 50 jumps there is basically no difference between them.

The confidence that SL students get from going by themselves is immense. I would love to see a course that combines them. Maybe its time we planned the TM-SL-AFF training table Cool


diablopilot  (D License)

Mar 11, 2007, 5:27 PM
Post #19 of 60 (1732 views)
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
In reply to:
I was wondering why Line Twists are more common on the SL as oppose to Freefall from a higher altitude?
I guess that your body position on exit plays a great part, but surely that applies in all situations and not just SL?

Welcome to the sport!

It is because of wrong body position. You do not have time to correct it. On AFF you have more time to correct it. I think AFF is safer.

Start doing AFF jumps and you might change your mind.


Premier billvon  (D 16479)
Moderator
Mar 11, 2007, 6:02 PM
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Re: [koppel] Static Line twists / First freefall [In reply to] Can't Post

>S/L students tend to be more independent and self-sufficient over
>their AFF counterparts in the early days off student status.

Definitely true. There are some significant differences between AFF and SL grads. AFFers tend to be a bit better at RW and tracking at breakoff. SL jumpers tend to be somewhat better at spotting, exits, pulling stable and opening at a given altitude. They also seem to be better under canopy. A big part of it has to do with the number of jumps at graduation - a SL grad has far more jumps (even if the freefall time is similar) than an AFF grad, and has had correspondingly more training/practice with spotting, exiting, opening at a given altitude (after varying delays) and landing.

In terms of freefall skills, I think AFF gets you more, sooner. In terms of survival skills I think SL has a lot of advantages.


aguila  (B 1009)

Mar 11, 2007, 7:49 PM
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Re: [dragon2] Static Line twists / First freefall [In reply to] Can't Post

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YI, I do not know anyone named Doug, I went through SL as did most at my DZ, and the skygod would be a skygoddess Laugh

Good for you! Wink but I wrote DougH Angelic. BTW:

If you are kicking, rocking or twisting just as the bagged canopy lifts off, you can impart a twist to it. The principle is the same as when you give a Frisbee disc a flip of the wrist on launch. Line twist are more common on static line than freefall jumps.

Parachuting - The Skydiver's Handbook, pag 142. Dan Poynter, Mike Turoff


aguila  (B 1009)

Mar 11, 2007, 8:44 PM
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Re: [diablopilot] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
In reply to:

Welcome to the sport!

It is because of wrong body position. You do not have time to correct it. On AFF you have more time to correct it. I think AFF is safer.

Start doing AFF jumps and you might change your mind.

I did six AFF jumps right after SL and that is why, IMHO I think AFF is safer.


Premier billvon  (D 16479)
Moderator
Mar 11, 2007, 8:57 PM
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

>that is why, IMHO I think AFF is safer.

I think in terms of risk to the student it depends on what time you look at the progression.

For the very first jump, SL is safer. There's less chance of a student getting away from the JM without an open canopy. On a static line jump, you have to exit without a SL hooked up to "get away" from the JM without the parachute being opened, and it's easier to ensure that you have a SL connected than it is to make sure a ripcord gets pulled/a PC gets thrown after 45 seconds of freefall. Malfunction rates are about the same in my experience with decent gear.

For the higher levels, AFF is a bit safer, simply because you have similar situations (freefall with a JM) but AFF gets you a better JM.

Once they graduate, as I've mentioned before, the SL guy has a bit of an edge since he has had far more training on spotting, exiting, deploying stable and landing safely.


aguila  (B 1009)

Mar 11, 2007, 9:07 PM
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Re: [billvon] Static Line twists / First freefall [In reply to] Can't Post

In reply to:
>that is why, IMHO I think AFF is safer.

I think in terms of risk to the student it depends on what time you look at the progression.

For the very first jump, SL is safer. There's less chance of a student getting away from the JM without an open canopy. On a static line jump, you have to exit without a SL hooked up to "get away" from the JM without the parachute being opened, and it's easier to ensure that you have a SL connected than it is to make sure a ripcord gets pulled/a PC gets thrown after 45 seconds of freefall. Malfunction rates are about the same in my experience with decent gear.

For the higher levels, AFF is a bit safer, simply because you have similar situations (freefall with a JM) but AFF gets you a better JM.

Once they graduate, as I've mentioned before, the SL guy has a bit of an edge since he has had far more training on spotting, exiting, deploying stable and landing safely.

Thank you! It makes sense to me.


14000andfalling  (Student)

Mar 12, 2007, 7:08 AM
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Re: [aguila] Static Line twists / First freefall [In reply to] Can't Post

The quote from the handbook is one of the reasons I asked this question in the first place as i've been reading a copy prior to my SL course.

Maybe AFF would get me more freefall time overall, but I kinda like the idea of doing it in 'steps' that are a little more drawn out (Not to mention cheaper!) and as you said jumping alone the first few times can only be a good thing in terms of confidence building and canopy practice right?

Well, I guess we'll find out in just under 2 weeeks!


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