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after watching video of a days jumps in which one person had a 180 i noticed how much oscilation there was when jumpers aggresivly chucked the pc. ive heard some talk of just realeasing the pc with less force but have never seen anyone do this.

im interested in hearing different opinions of
releasing vs. throwing the pc on handheld jumps.
what method do you use? how does it contribute to/ reduce pc oscilation, hesitation and bridle wrap.

i researched this topic in the archives but couldnt find exactly the info i wanted. i didnt spend hours looking though so sorry if this topic has been done to death.

Think, tossing it like a dart.

I don't think just "releasing" the PC is a good idea. I could see how an aggressive through could throw off symmetry though. As hookitt said, throw it like a dart.

I think just releasing it would greatly increase the chances of a bridle wrap, and the PC getting caught in your burble.

What kind of delay did the jumper that had the 180 take?

Just curious as I thought that ocillation usually happened during fairly high speed deployments (not usually the hand held kind of jumps).

I personaly belive that having a lazy pitch or "release" is dangerous I have personaly seen some one go in due to a lazy pitch, and one person almost go in due to a lazy pitch (in what I would consider high winds) that resulted in a bridle wrap which he cleared. I personaly chose the direction, force of the pitch and PC folding technique based on the specific jump eg. wind conditions, exit point, hesitation importance, object strike posobility and a few other factors.

 
Back when we used 48 and 52 inch pilot chutes on all but terminal jumps we were still arguing about whether cross winds caused off heading openings.

Almost everyone threw pilots chutes like they were hand grenades. And it wasn't until we started videoing a lot of jumps we realized heavy pilot chutes thrown hard were causing off heading deployments.

Throw it like a dart is an elegant saying, but I prefer the axiom – "positive deployment" which is somewhere between a dart and a hand grenade. After all, you can deal with an off heading opening but no canopy is game over . . .

Probably the important point is to get it out there, but not hard enough that your shoulders aren't squared up for deployment.

NickD
BASE 194

What are "your" thoughts about the tossing it up method if you are jumping low?

Not nescessarily...
This is from a 180 I had beginning of last year which resulted in a interesting heli rescue and some nightmares I had afterwards for about a year...
Bad scarry jump...

when people use the term pc hesitation, besides the obvious what exactly does that look like. is the pc not inflating but more flapping around, or is the pc inflated but just not dragging out the canopy for some reason? is a pc caught in a burble considered "hesitation"?

it was a 1-2 sec delay. it doesnt appear the pc had much to do with the 180 to me.

Wow. Glad you are Ok. I guess I just never paid any attention to the PC on shorter delayed jumps (I've never witnessed a 180 like that though)...maybe I'll look harder next time.

I can see at least 1/2 a rotation before line stretch. Is this common with big PC's and short delays? It really didn't look like it was induced by the throw. I'm really curious now as I've been told by many experienced people that oscillation isn't an issue with bigger PC's (hence the lack of AV's on most).

How much do oscillations really lead to off-headings? In KL, I watched a few hundred jumps over the course of the three days, and the vast majority of the oscillating PCs did NOT result in off-headings. I saw some wildly oscillating pc's result in perfectly on-heading openings.

Mikki, the oscillation in your video was so mild, it seems highly unlikely that it caused your 180. Actually it looked as if the osc might have been caused by the packjob turning! ;-)

This could be worth a thread on its own, but I think that pc oscillation is definitely not the leading cause of off-headings. It seems that more often than not, something else causes the packjob to turn before line stretch is complete, particularly in sub-terminal openings. When the packjob has not begun turning by line stretch and then does afterward that's 99% body position. But I don't know anything, really.
This is my favorite topic though, and it's great to hear people's thoughts on the great black mystery of our sport...

if you talk low jumps my way then i think its brilliant combined whith a more standing/falling position.

throughing your pc too hard gives you all chances of getting a offheadding.
first you force the pc one direction it has to go back and cant stop its moving by it self,there fore it oscelate(or were it mastrubate difficult speaking here)
second,thoughing your pc hard makes you unstabel and more prone to tip a shoulder which also gives you a offheadding.

Whith nowdays 9ft bridels and speaking hh i would say that getting caurght in a buble on your back is pretty much not posible...

Like Hookit said,on regular hh jumps throgh it like a dart..

Mikki: The oscillation doesn't look like much, but I'd swear the PC reaches a steady state pulling back toward the cliff, instead of directly above you. Does anyone else see this, or is it just a visual trick? How careful are you, generally, about attaching your PC symmetrically?

Michael

I agree with what you are saying.
On that particulary day there was a lot of thermics (not very good for that jump...)
I think the thermics caused the pilot chute to oscillate but I also think that the oscillating pc was not what caused the 180. If you look at the vid you can see that the canopy comes out of the container with a spin and when it reaches line strech the canopy is already facing the wall. I think in that case it is possible that the thermics caused the canopy to come out of the container spinning. But like you, I also don't know anything ... This is just speculation.
And most probably it was just bad luck combined with black death and shit happens...

I usually check if the pc is atached symetrical by standing on the bridal and pulling the pc up to see if the load tapes are parallel. But it is possible that I did not do it on that jump.
And yes, I also think that the pc does one oscillation and then points torwards the cliff. But this could be also because I jump away from the cliff and the pc is in straight line to the falling direction.

This is one of those rare videos of 180 where you can clearly see the twisting motion of the canopy during extraction.

Do you have a high quality version with 30 frames/s so we can analyze it frame by frame?

I'm really not sure if thermics would cause your packjob to start rotating instantly as it came out of the container... I would expect it to come out relatively straight, then as the thermic/wind/air movement overcame the packjob's inertia it would slowly accelerate into a spin. The way it (seems to, IMO) rotate at the same speed from extraction to line stretch suggests (to me) that something caused it to start rotating as it came out of the packjob, and then it just continued rotating until linestretch because nothing stopped it from spinning once it started.

Perhaps the part of the bridle below the pins (in the container) worked its way around one of the ears, or maybe the attachment point wasn't centered?

edit: It really is kind of hard to see closely in the video you posted.. a higher-quality format at the original framerate would be interesting to see frame-by-frame, as yuri mentioned. Glad you're OK!

Here ya go

Just a guess... the lines may have gotten hung up on one side of the tail pocket for a split second -- enough to spin the canopy. From the video it doesn't look like they come out clean. At the point of deployment when you'd expect the lines to start paying out, the canopy bunches up and it looks like that is when it spins.

I've gotten down after a violent off heading and found half my tail pocket open indicating a possible hang up.

Thanks for sharing the video, and glad you made out ok.

I can't seem to play the video in either Windows Media Player or QuickTime. WMP says, "The file is either corrupt or the Player does not support the format you are trying to play." What am I missing? Thanks!

Michael

It worked in winamp for me.

that's another possibility that I think might cause offheadings more often than people think. People are very quick to blame them on things like winds or oscillating PC's.

Vid666 has a video of a 180 he had that you can play frame-by-frame and see that it comes out straight for about a foot or two, and then starts rotating suddenly and continues rotating until line stretch. All it would take to trigger a rotation is a line or two getting snagged momentarily on the hook side of the velcro, or a loop of line getting looped around another one and having to pull free by blowing through one side of the velcro, etc

There was a slight crosswind coming from the direction of the offheading, which seemed to make everyone assume that the wind caused it, but I personally think it was a line snag or something else. Maybe he can post a link to see what everyone thinks?

try the recoded wmv version: MikkiZH.wmv

I believe the one and only cause of this incident is the big black cloud above michi's head....

Nope, absolutely clear 100% by checking video frame by frame that it's oscillating PC that is turning the canopy.

Case closed.

Thanks for the video!

not inflated, flapping around, partially or 1/2 inflated but not causing enough drag to really do anything.

fully inflated but not dragging out = pc in tow

though it's really cool when you're doing a low freefall and have enough time to look up at your pc and watch it hesitate for some fraction of a second. well, it's really cool a couple days later when the shock wears off.

watching my friends vid from a few days ago it looks like the canopy bundle hangs up for a split second on the right top corner turning the canopy mass 180 to that direction. after talking to him he remembers making his top fold to long and having excess bulk in the top corners.

im getting the feeling alot of 180's get blamed on pc osciltaion. although i fell this does happen it just doesnt seem like its the main cause. after watching alot of my vids MOST of the pc's are osciltaing quite a bit with perfect openings. so why do most open fine but occasionaly cause a 180. there must be another variable. im guessing pack volume catching on the top corners is this variable.
my apex dp doesnt open as wide on the top as the bottom until the riser covers open. that doesnt happen until after line stretch and by then the damage is done. until those covers open the top of the container is pretty tight and able to cause a hang up quite easily. i wonder if
opening the riser covers prior to exiting on short delays could provide a cleaner extraction.
any thoughts?

>>What are "your" thoughts about the tossing it up method if you are jumping low?<<

I know it works, but man you've got to be a real believer to use that method. Dwain Weston is the first person I saw do that to jump our little cliff in So Cal. We had always thought about freefalling it for years, and many of us, including me, stood on its edge pilot chute in hand just staring at it, and staring at it, and staring at it . . .

When Dwain came for a visit we took him there and he did indeed make the first freefall from it. And that was after what? Probably over a thousand direct bag, PC assist, and static line jumps. "You just throw the pilot chute up." Is what he said after landing.

After he left town I stood on its edge pilot chute in hand just staring at it, and staring at it, and staring at it . . .

NickD
BASE 194

It looks to me like the canopy is coming out nice and straight and then when the last fold is coming out of the tray it starts to spin, as if the tail pocket section got hung up on the container on the way out.

Do you have dynamic corners? Do you shake the canopy into the bottom of the container after you close it up?

Ya know, it really looks like the canopy was moved around by the pilot chute. The PC moves like it was influenced heavily by wind. It doesn't take all that much to move a pilot chute and it looks like once it pulled on the top of the parachute and started turning it, it continued.

The FastTrax swoop team opens their riser covers before they exit when they do hop-n-pops. They say the opening is cleaner.

Not that I'm trying to compare the two sports.

Vid. looks really like the canopy followed the rotation exactly with the PC movement right to line-stretch/bottom skin pop.
.

That is a much simpler way to put it.

if you look at the bridle right after the throw it is twisting already I think that started the twist of the canopy at the bridle stretch, when the pilot chute move toward the cliff from the thermal the canopy is off to the right of the jumper, right before the line stretch if you look at the line one side has lots of slack than whack 180. look like not just one thing it was a chain of event (thermal wind, bridle twisting, canopy twisting, canopy not directly above the jumper causing slack line on one side)
at MOAB in summer time there is lot's thermal, so most of the people don't even bother unless early in the morning or late afternoon when there is no thermal
cross wind, thermal badddddddddd

yea, after seeing the higher-res video it definitely looks like that's the case

may be camera & lens but also left knee and hip not symmetric with right side. Left knee/hip looks dipped. may have compounded it even more.

FYI. In the skydiving past people did have off heading openings as well. They also thought about the PC oscillation. So, what - some - people was putting a 2 part (turning) metal device between the bridle and the canopy attachment. So, when the PC and bridle turned, this turn would not influence the top of the canopy. Did it help? Not quite.

Now, an oscillating PC causes the bridle to pull the total canopy in a certain direction. In theory, and for sure in some practice cases, this would influence the heading of opening. But, as said in this thread as well, there are quite a few, if not many cases that a PC oscillates or turn with a perfect on heading opening. All we tend to see here are videos of oscillating PC's leading to an off-heading opening. Where are all those video's with oscillating PC's and on-heading openings?

Furthermore, I to notice that generally speaking a canopy wants to open into the wind (especially with low speed slider-up jumps). Also, they open dead-on heading, even with wind from the side. Sometimes, but that is a minority, they open away from the wind direction.

I have also seen quite a few pack jobs leaving with 100-180 straight out of the container with NO wind and NO oscillating PC.

Taking all that into (my personal) account, I believe the heading of an opening is much more influenced by wind blowing on the canopy, than the oscillating PC. Of course, that is all open to debate.

Ronald

" Taking all that into (my personal) account, I believe the heading of an opening is much more influenced by wind blowing on the canopy, than the oscillating PC. Of course, that is all open to debate. "
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..."I believe the heading of an opening is much more influenced by wind blowing on the canopy." . That is mostly true for lower air speed deployments but once the jumper moves up in delays like 2-3-4-5 Second, etc. He/Her (in general terms) is moving much more faster than the wind is moving at deployment and the body weight is the relative energy that is pulling the deployment to inflation and all other inside/outside influence takes over from that point on.
Most defiantly, all deployments of 3 seconds and under will be under the biggest influence of wind on fabric. Now Also, slower air speed deployment are easier pulled by the PC also.
Do not underestimate the force and drag of a PC when being pulled by a jumper even moving under a 3-second delay and what is influenced when the body drag-force is moving in different direction of PC drag energy.
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