Pull vs Throw out

[nutter 0]

I have been thinking about his for a while now.
I have hurt my neck on 3 occasions with hard openings.I have tried all and every possible way of packing and have settled down to a "positive" opening canopy(Hornet 170 - wing loaded to 1.67)>it always seems to hurt on the low alt jumps,sub terminal openings.
However is there a chance that when the bag is extracted from the container,and I jump pull out, so the container is fully open, that this happens faster,etc on the deployment sequence. .If i changed to a BOC, would this be slower as the bridle extends fully then the pin, blah blah.....

seriuos opinions accepted, damn my heads hurts

p.s. The hornet flies like a dream,responds ever so well to my input via toggles , and WOW on risers. gr8 glide and tonnes of lift.

"Expecting the world to treat you fairly because you are good is like expecting the bull not to charge because you are a vegetarian."

[davelepka 4]

Two words: Performance Designs

[nutter 0]

well thanks for that informative, but USELESS information you just gave.
I have done a few jumps on the Spectre and that seems to be the way to go for my neck and I
What would you recommend from PD as a matter of interest.

Still, the question posed, could a deployment system make a differnce in anyway what so ever, and why

"Expecting the world to treat you fairly because you are good is like expecting the bull not to charge because you are a vegetarian."

[davelepka 4]

The info is not useless. The size of your pilot cute is what will effect your deployment, not the way it is deployed.

Buy a PD canopy. Be happy for a long time.

I don't know what you want out of a canopy, but the openings on the Sabre2, Spectre, Stiletto, and Velocity are all excellent. All will perform better then your current canopy.

[nutter 0]

you mentioned Pilot chute size.....explain more please.
Smaller better, well dont tell the ladies ha ha ha

So even if the container is fully open as in pull out, and i get a smaller pilot chute this will "slow" down the deployment speed(minimal)but then what about low alt jumps then under 2000' for display jumps

"Expecting the world to treat you fairly because you are good is like expecting the bull not to charge because you are a vegetarian."

[PhreeZone 15]

A smaller piilot chute will have less pull force on the canop. Too much pull on the canopy can lift the bag and canopy clear of your container too ofast and this can lead to hard openings.

Which size slider does your canopy have? Too large or too small of a slider can alter the openings too. A slider thats the right size for terminal openings might be too large for clear and pulls and has hard openings. One slider might be right for terminal but too small for subterminal, it all depends on the canopy.

For PD canopies... the Spectre and Sabre2 are both great opening canopies.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[nutter 0]

so how does one work out the PC size relative to Canopy size,
ZP vs F1-11?

They did have an issue on hard openings and did increase slider size.

does Pull out make a diff vs Throw out on this

"Expecting the world to treat you fairly because you are good is like expecting the bull not to charge because you are a vegetarian."

[rmsmith 1]

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does Pull out make a diff vs Throw out on this

No, no smoking gun here.

Take the earlier advice, Performance Designs!

[Blahr 0]

I have heard that the Hornet can give hard openings but that through packing technique can be controlled.
I cant advise as to which packing method provides the softest openings but you might want to explore this option

[TomAiello 25]

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A smaller piilot chute will have less pull force on the canop. Too much pull on the canopy can lift the bag and canopy clear of your container too ofast and this can lead to hard openings.

Can someone explain why this is? Does adding the bag create some kind of extra sensitivity to the PC?

I've taken 42" PC's to terminal, and (aside from making my pack job into a jumbled mess by stripping the center cell) the opening wasn't really any harder than a 32" PC.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[Hooknswoop 19]

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A smaller piilot chute will have less pull force on the canop. Too much pull on the canopy can lift the bag and canopy clear of your container too ofast and this can lead to hard openings.

I've found that PC size doesn't make any difference in how hard a canopy opens. A larger PC will cause it to open in less time, but not harder. Once the canopy is out of the bag and the PC collasped (for collaspable PC's), it has zero effect on the opening. Even a non-collaspable slider won't have much impact on opening once the canopy clears the bag.

I experimented w/ a PC, kept trimming it down, smaller and smaller, until I had to reach back and pull the pin 30% of the time and sub-terminal it would tow. The openings never changed and I could still get 'brisk' openings w/ the very small PC.

Derek

[rigging65 0]

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A smaller piilot chute will have less pull force on the canop. Too much pull on the canopy can lift the bag and canopy clear of your container too ofast and this can lead to hard openings.

Negative. In my experience, the pilot chute will get you to line stretch faster but it doesn't much change the way the canopy itself opens.

Canopies open hard because of two things: the way they're packed and the size/shape of their slider. And even how they're packed is less of an issue than slider placement and size/shape.

Line stows don't matter (as long as the bag stays closed until it's supposed to), deployment type doesn't matter, p/c size and type don't matter (I've jumped several canopies with about 6 different size/material p/c types...didn't do a damn thing to them).

Some canopies open better than others...and even within the same model canopy you can run into random rogue canopies. Mfgs. can sometimes correct for this with different size (or shape) sliders. Ask the Mfg.!

"...and once you had tasted flight, you will walk the earth with your eyes turned skyward.
For there you have been, and there you long to return..."

[jumper03 0]

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*** A larger PC will cause it to open in less time, but not harder.

Okay, now that confuses me -
When we say "hard" opening you really mean a fast opening - insta-canopy being the hardest. Everything you can do to slow down the opening sequence makes for a soft opening - correct?

As I understand it, speaking strictly from the physics side of it, the higher the acceleration, the harder the opening. Terminal speed doesn't change, the speed under canopy doesn't change so the only variable you can control to affect hard or slow is the length of time it takes to go from terminal to under canopy.

So how can you open the thing in less time but not be harder?

Jump

Scars remind us that the past is real

[TomAiello 25]

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So how can you open the thing in less time but not be harder?

The force exerted on the jumpers body is not consistent throughout the opening sequence.

In other words, an opening might be soft for three seconds, then really hard for half a second, then really soft again for three seconds. So, in total, a six and a half second really hard opening.

Or, it might be medium hard for six seconds. So, in total, a six second medium hard opening (shorter, but softer).

The thing to remember is that force exerted on your body is not constant throughout the opening sequence.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[PhreeZone 15]

That makes total sense... That brrings up the question, is there any merit to the arguement of lighter grommets on a slider makes it open softer?

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[jumper03 0]

So to continue in nerd speak then -
essentially what you are saying is that the acceleration from terminal velocity to that under the canopy is not constant and smooth.

So now, my newb question, what causes those 1/2 sec deviations from a constant acceleration?

I would guess one would be right when the chute gets out of the bag and the acceleration takes a bump....

Scars remind us that the past is real

[Hooknswoop 19]

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Okay, now that confuses me -
When we say "hard" opening you really mean a fast opening - insta-canopy being the hardest.

Opens faster, meaning in less time and altitude. W/ a larger PC, it takes less time for the canopy to come out of the bag, the rest of the opening is the same. A smaller PC requires more time for the canopy to come out of the bag, more time and altitude for the canopy to open, but once the canopy is out of the bag, the openings are the same.

So the size of the PC affects the time it takes for the canopy to come out of the bag, not how hard the canopy actually opens. The canopy can come out of the bag quickly and open softly.

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Everything you can do to slow down the opening sequence makes for a soft opening - correct?

The speed at which the canopy gets to line stretch and comes out of the bag can be different but result in the same amount of deceleration forces experienced by the jumper.

If a canopy is packed slider down and is deployed with a large or small PC, the opening will be hard. Slider up with a large or small PC will result in a normal opening.

Derek

[mjosparky 3]

Nothing that happens before the canopy clears the bag affects the opening behavior of the canopy. One of the biggest causes of "crack" openings is allowing the slider to move down the line during packing.
Sparky

My idea of a fair fight is clubbing baby seals

[jumper03 0]

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If a canopy is packed slider down and is deployed with a large or small PC, the opening will be hard. Slider up with a large or small PC will result in a normal opening.

Yes, I've had the misfortune of meeting Mr. Down Slider. Bruises around my shoulders and twixt my legs for over 3 weeks and couldn't even put on a rig without it hurting. That's what got me really interested in learning about how the rig functions and how to maintain it and mabye even tweek it.

I know what you're saying makes sense, I've felt it, but now I want data

Jump

Scars remind us that the past is real

[TomAiello 25]

I seem to remember Dan Preston of Atair posting some video of openings with g-forces (from their datalogger) graphed across them a while back. Maybe do a search (or just call up Atair and see if they'll share their data with you)?

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[apoil 0]

Quote

Canopies open hard because of two things: the way they're packed and the size/shape of their slider. And even how they're packed is less of an issue than slider placement and size/shape.

The design of the canopy itself plays an important role as well.
So if you are comparing openings of the same canopy, then yes, those two things matter, but since you bring about shape of the slider, it seems as if you are talking about generalities.

And if you disagree, I invite you to try jumping a crossbraced canopy without a partially formed nose. There's a reason they don't make them that way - they would break you.

[dterrick 0]

Hi Peter

PUD vs BOC will change nothing about the snivel or inflation stages of the opening sequence. From my experience demo'ing PUD's, you'll find the snatch force hits sooner than with a BOC. With the same pilot chute it will feel the same. The p/c's job is to pull the pin, extract the bag to line stretch, and then pull the bag off the canopy.

Then you have the snivel. The slider is the device that keeps the canopy from opening with a BANG all at once. LArger sliders offer more resistance. Many original Sabre owners have larger sliders made - indeed the slider size on Sabre 2's is HUGE by comparison. youcould also have your rigger sew a 'pocket' onto your existing slider.

THIS stage of deployment if often the key between a slammer and a not slammer. If you look up at your canopy right after you;re tugged upright and it is 'shimmying' open you have a 'snivel' and a soft opening. If you look up to find an open canopy - you need a bigger slider! I jump a Raven main (reserve design, supposed to open with a BANG) and a larger and pocketed slider is what it took for me.

Yes, you'd love a PD Sabre 2. If you decide to go that route, sell me your hornet cheap?

-Dave

Life is very short and there's no time for fussing and fighting my friend (Lennon/McCartney)

[Scrumpot 1]

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Nothing that happens before the canopy clears the bag affects the opening behavior of the canopy.

Maybe not the opening behavior of the canopy itself, considered in isolation, but considered as an entire sequence and it's affect on your opening shock, it sure can! ...Ever heard of LINE-DUMP before??

I agree, that PC size, aside from the relative speed it may get your d-bag to line stretch, will in reality have NO affect on your canopy's opening speed (or shock in this instance) ...but if your lines are not entirely stowed, or otherwise "dump" before you have come to full line stretch ...when that canpoy leaves the bag, I gauran-f'ing-tee you it's gonna HURT (at the very least)!

And Mike.... THAT does indeed happen BEFORE the canopy leaves the bag.

coitus non circum - Moab Stone

[Hooknswoop 19]

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Ever heard of LINE-DUMP before??

Line dump, or the lines coming out of the stows prior to line stretch will not cause a hard opening. (I've jumped several canopies as mains packed in a reserve free-bag with only locking stows and they snivelled. Others have jumped their mains w/o stowing any lines beyond the locking stows.). Bag strip or the canopy coming out of the bag prior to line stetch will/can cause a hard opening. Bag strip is very rare and is difficult to make happen. The locking stows must come un-done prior to line stretch. Look at a d-bag. If the grommets are 4 inches apart and you make 2-inch stows, there is equal lines (and weight) outside the stows as there is inside. Therefore, they don't tend to 'fall out' of the stows. With 2 1/2 inch stows, there is more weight on the outside of the stows and forces keep the stows in place intill they are pulled out.

Even BASE rigs, with no d-bag at all can open soft.

Derek

[Scrumpot 1]

I stand corrected as to my techical terminology.
mia culpa.
Thanks swoop!
-Grant

coitus non circum - Moab Stone