Forums: BASE Jumping: BASE Technical:
180s
Premier Sponsor:

 


fbc91

Dec 23, 2020, 2:30 PM
Post #1 of 18 (2016 views)
Shortcut
180s Can't Post

What causes 180's when the jumper has done everything right: pack job, body position, etc.?

Dadsy

Dec 23, 2020, 5:27 PM
Post #2 of 18 (2009 views)
Shortcut
Re: [fbc91] 180s [In reply to] Can't Post

During my course we packed intentional 180s and 2 of the 6 from memory came out on heading, so I don't think there is a definitive answer.

Is there footage of the body position and the PC

fbc91

Dec 23, 2020, 7:59 PM
Post #3 of 18 (2001 views)
Shortcut
Re: [Dadsy] 180s [In reply to] Can't Post

In reply to:
Is there footage of the body position and the PC

Not a jumper, just curious what the theories are.

Colm

Dec 23, 2020, 8:11 PM
Post #4 of 18 (1998 views)
Shortcut
Re: [fbc91] 180s [In reply to] Can't Post

I have proposed the quantum theory of BASE. There is a probability distribution describing your opening heading, which is influenced by random chance, packing technique, wind integral, pilot chute symmetry, body position, state of sobriety, karma balance, and the observed angle between Jupiter and Saturn.

Like Schrodinger's cat, your parachute is literally simultaneously open facing all heading directions until you deploy it, and thus collapse the waveform by making an observation.

In other words, nobody really fucking knows, and my theory is not provably worse than anyone else's.

Dadsy

Dec 23, 2020, 8:40 PM
Post #5 of 18 (1992 views)
Shortcut
Re: [Colm] 180s [In reply to] Can't Post

I think this may be the most sense you have made Smile

higherground

Dec 24, 2020, 10:37 AM
Post #6 of 18 (1959 views)
Shortcut
Re: [fbc91] 180s [In reply to] Can't Post

- pilot chute out of trim
- winds ( meteo and relative - from a running exit )
- pc and bridle pendulum going past center
I’ve seen this mostly from a hard throw stowed with too short of a delay ( 0 to 1.5 sec with a 42 “ ) works out most of the time
- random chaos

Colm

Dec 24, 2020, 8:08 PM
Post #7 of 18 (1928 views)
Shortcut
Re: [Dadsy] 180s [In reply to] Can't Post

lol don't get too used to it Laugh

rendezvous

Jan 3, 2021, 11:54 AM
Post #8 of 18 (1568 views)
Shortcut
Re: [Colm] 180s [In reply to] Can't Post

Lol! love the collapsing wave function theory, this one will stick with me ????

Kadel

Jan 3, 2021, 3:00 PM
Post #9 of 18 (1559 views)
Shortcut
Re: [higherground] 180s [In reply to] Can't Post

What about bigger PC's, 46" or 48" stowed? I don't like it, but sometimes I have to do (mostly because tricky exit). But i saw two almost clear 180's at this type of jump at two different jumpers. In my opinion that was too big PC+hard pull= oscillation PC with packjob to left side..


(This post was edited by Kadel on Jan 3, 2021, 3:02 PM)

higherground

Jan 3, 2021, 6:38 PM
Post #10 of 18 (1548 views)
Shortcut
Re: [Kadel] 180s [In reply to] Can't Post

I’ve never done a jump with a pc over a 42”.
I wouldn’t want to introduce a possible hard pull into the mix at low altitude. For your jumps , I’d take a pca, static line or just pass altogether.
For the off headings I’ve seen with a 42 stowed short delay. It’s a hard throw to bridle extension and then the momentum of the bridle/ pc pendulum carries the pc past center to the left side of the container for the off heading. A little more airspeed from a longer delay helps to keep the pc centered. If a longer delay isn’t available, I’d go handheld.

Faraday

Jan 11, 2021, 2:45 AM
Post #11 of 18 (1409 views)
Shortcut
Re: [Kadel] 180s [In reply to] Can't Post

I think, it's a combination of PC size and delay in that case. I'm not sure, if there is a difference between going stowed and handheld (if body position is stable).

I noticed some kind of pattern jumping a 46'' PC based on delay. As soon as delay reaches approx. 2 sec, heading performance gets worse. No 180s, though, but 45° to 80°...

Anyway, I guess the reason is a combination of a too big PC (for the delay), resulting in to high air speed = much air spilling the PC = oscillation. I all those cases, PC thrown to the right with oscillation to the left resulting in an off-heading opening left. I think, that matches your observation.

John_Scher

Jan 11, 2021, 8:55 AM
Post #12 of 18 (1392 views)
Shortcut
Re: [Colm] 180s [In reply to] Can't Post

 
very clever and very funny:


Like Schrodinger's cat, your parachute is literally simultaneously open facing all heading directions until you deploy it, and thus collapse the waveform by making an observation.

In other words, nobody really fucking knows,...

taj

Jan 14, 2021, 6:46 PM
Post #13 of 18 (1254 views)
Shortcut
Re: [Faraday] 180s [In reply to] Can't Post

Just wondering if your 46” pc is vented or non vented ?

base698

Mar 25, 2021, 6:13 AM
Post #14 of 18 (557 views)
Shortcut
Re: [fbc91] 180s [In reply to] Can't Post

Why are 180s so uncommon on static line jumps? What's different about them compared to freefall?

giacomo

Mar 25, 2021, 11:13 AM
Post #15 of 18 (541 views)
Shortcut
Re: [base698] 180s [In reply to] Can't Post

I'd say that the pull is cleaner (and possible faster) compared to the extraction with the PC. Then you have less time/speed to fuck off your body position and finally you have nothing to worry about so you don't move too much (and probably you're more relaxed too).

smak

Mar 30, 2021, 6:15 PM
Post #16 of 18 (443 views)
Shortcut
Re: [fbc91] 180s [In reply to] Can't Post

i'd say snivel is main proponent of 180s in your scenario.

the more time your lines stay all close to each other the more they have a chance of affecting one anothers path of least resistance, that is a clean opening.

the earlier you are in stage of opening the more dramatically a small catch on a line can get worse and worse in later stages.

static line with no slider, or even with, minimizes time the lines are all bound up and everything spreads out nice and quick.. facilitating on heading openings.

if you do everything right then pack job and body position is correct.. doesn't mean prevailing wind still cant throw you a loop.

base570

Apr 2, 2021, 7:48 PM
Post #17 of 18 (363 views)
Shortcut
Re: [base698] 180s [In reply to] Can't Post

base698 wrote:
Why are 180s so uncommon on static line jumps? What's different about them compared to freefall?

The difference is the PC and time in freefall and expand from there.

On a static line you essentially have no PC pulling or orbiting in any direction. There is a single fixed point of attachment not a variable point.
Your time in freefall is limited on a static line so there are fewer variables to affect the opening. i.e. airspeed, body position, PC throw direction and force, etc.

The lesson here is that PC's cause most 180's and must be banned. Perform freefall jumps at your own risk! Actually maybe we should ban those as well.

Colm

Apr 2, 2021, 8:44 PM
Post #18 of 18 (357 views)
Shortcut
Re: [base570] 180s [In reply to] Can't Post

base570 wrote:
The lesson here is that PC's cause most 180's and must be banned. Perform freefall jumps at your own risk! Actually maybe we should ban those as well.

Well 180s only happen after deploying, so go ahead and jump, just ban deployments.


Forums : BASE Jumping : BASE Technical

 


Search for (options)

Log In:

Username:
Password: Remember me:

Go Register
Go Lost Password?

D4DR Media