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Can anyone explain this opening?

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Grafico posted an AFF video in the sensory overload thread. I watched it and am curious. This is not related to the other thread so I copied it here...

Can anyone explain the slow opening that the camera person has? Would that be classed as a snivel?

-Michael

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Here is a link to a video of an AFF Level one dive recently. The student is clearly overloaded and the instructor has to pull for him. The student was stellar in ground school and is usually very good at task oriented activities... but the added fear factor, noise and whatever else contributed to him not passing this AFF L1.

AAF 1 Overload

Grafico

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That's called a nice, smooth, soft opening. B|

Has anyone explained how the parts of the canopy system work during opening?

During opening, the slider works against the canopy as it inflates. It's designed to slow the opening so you don't get what many of us refer to as a "thwack!!" of an opening (those hurt). The slider is catching air, keeping it pushed up. At the same time, the canopy is inflating from the center-cell-out. As the canopy inflates, your decent slows, pushing less air against the slider, allowing the canopy to inflate futher, and the line-set stretches with the canopy taking its shape. This pushes the slider down, et voila!

If the slider didn't come down, and the jumper had to unstow and pump the brakes, that could be classified as a "slider-up-snivel".

edit to add: looks like that student's going to be repeating that level huh... :P

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!

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edit to add: looks like that student's going to be repeating that level huh... :P

Looks like. One question. Why didn't the main side try to pull the student's arm back for an assisted pull?

Edited to ask: Does that Cessna have a camera step on it or is their camera man Spiderman? I've been all over C-182s and I can't ever remember trailing the door like that. Good way to do it.

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Observations:

Explain the opening: A the student did not pull thus the AFF-I assisted him. The cameraman turned away, thus I did not see the students opening.

Explain the opening: Camera person had a nice long snivel with the slider doing it's job, the manufacturer should be proud.

Secondary observation: Cameraman needs to check his/her shit! Red cable to close to the box looks like shit in frame :S



Fire Safety Tip: Don't fry bacon while naked

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Grafico posted an AFF video in the sensory overload thread. I watched it and am curious. This is not related to the other thread so I copied it here...

Can anyone explain the slow opening that the camera person has? Would that be classed as a snivel?

-Michael


Quote

Here is a link to a video of an AFF Level one dive recently. The student is clearly overloaded and the instructor has to pull for him. The student was stellar in ground school and is usually very good at task oriented activities... but the added fear factor, noise and whatever else contributed to him not passing this AFF L1.

AAF 1 Overload

Grafico




that would be classified as a perfect on heading opening.B|
Step into my (sub)terminal Playground

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Explain the opening: Camera person had a nice long snivel with the slider doing it's job, the manufacturer should be proud.



Some people call it a perfect opening and others say it's a nice long snivel. What is it? From the time he pulls at 1:28 until the slider reaches the bottom at 1:33 that seems like a really really long time. It is open with the slider at the top for almost 3 seconds, then it descends and everything is okay.

The most I've fallen was a 2 second delay but my chute seemed to be open well under a second from releasing the PC. Maybe things take longer than I realise.

-Michael

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The most I've fallen was a 2 second delay but my chute seemed to be open well under a second from releasing the PC. Maybe things take longer than I realise.

-Michael



"Well under a second" is way fast. You certainly wouldn't want tha as a rule on any canopy at terminal, unless you are at 200 feet. Also, be careful when discussing this to specify exactly when the timing starts and stops--at pilot chute release, when lines are stretched, bag opening... slider down....?

To reiterate the views of others, that looks like a fine and dandy opening to me.

-- Jeff
My Skydiving History

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John,

$100 says there's no "camera step" just a standard door hang exit. Put your right foot on the back edge of the step (or better yet the tire) and hang from the back of the door frame. The trick is to slide down the plane and not to flip out and "thump" against the plane. A "thump" is hard on the quarter window (read: generates cracks in the plexi) and makes is harder to hang on.

Its a popular exit for "clutered" step jumps (such as this example with AFF) and with big tandem students.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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>Some people call it a perfect opening and others say it's a nice
>long snivel. What is it?

Both. It's the sort of openings cameramen like because it's easy on their necks. I prefer a faster opening, but many people do not.

>but my chute seemed to be open well under a second from releasing the PC.

That's 200 feet per second in 1 second, or 10G's if it's one long steady drag. Since it takes at least half a second for the PC to pull the bag out, that would actually be around a 20G opening. That would likely cause canopy and/or riser failure (as well as being extremely painful) so it's likely a bit longer than that. Perceptions are compressed at such times.

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its a great opening. i have a spectre, a parachute noted for its "long" good openings....this opening doesn't look any different than the ones i have every time. at first with my sprectre it, did seem like it sniveled too long, but then once you do a quick glance up, you can see by the shape of the "snivel" that it will be a good deployment.

just ask my wfe it you would want a "quick" opening. the answer would be NO! she had a total malfunction, could not deply the pilot chute from the BOC...had to go straight to reserve at terminal velocity. sufered whiplash and could not lift her head up with her neck muscles for a week or so.


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Some people call it a perfect opening and others say it's a nice long snivel. What is it?



They are the same thing.

The snivel is a part of the opening sequence of every canopy. It is supposed to happen. Generally speaking the longer the snivel (within reason) the softer the opening.
Do you want to have an ideagasm?

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Yup - that's a nice opening (and soft). For those folks that have large enough canopies (like a 150sqf canopy loaded at 200lbs), the jumper actually decelerates during the slider-up phase of the opening. So, when the slider heads down and the canopy starts expanding, the jumper's fall rate is slower and the resulting opening force is lowered (compared to that of a very fast opening - remember, canopy drag is proportional to the square of the fall speed). So, a long snivel is beneficial in most cases.

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Interesting and I can understand your points. Remind me next jump to put my head up as I toss out the PC. Maybe things take longer than I realise. I haven't had more than IAD and one PC so maybe things will change as I drop faster.

-Michael

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