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HydroGuy

Hard opening on a go and throw...WTF???

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The velcro is perfect. And the TP is so friggin huge that there is no way to not line it up correctly. My Flik 266 is the smallest canopy Apex uses the large TP on.

I actually trip out on the size of the TP...my Rockdragon has a very small tailpocket, it requires being carefull to properly mate the velcro once you have stowed your lines. My Flik is the opposite. It's like 50% larger than it needs to be.

And I think the brakes are good. I've taken this setup off 240' B's and 265' B's HH and SL as well as higher S's and been satisfied with the settings. Had people from above filming and observing openings off a 370'B and everyone has agreed that brakes are satisfactory.
Get in - Get off - Get away....repeat as neccessary

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Ditto, I'll use a ZP 42 above 210 or so.



Based on what reasoning..?
It inflates quicker?
Less time to line stretch..?
More comfortable opening?

or rather...why wouldnt you use a 46?

At my experience level...I just wouldnt consider not using a 46+ at 210ft

I'm interested..not criticising :)

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"Line dump" won't cause a hard opening on a go and throw. Think T.A.R.D. That's real line dump. (ok, so there's no air speed)

In the bagged deployment world, if the bag stays shut until line-stretch, the canopy will not be affected. If some how the bag was stripped off the canopy, then the opening will be affected. Bag Strip is extremely rare. All that is needed are the locking stows. The rest of the line stows are only there to keep them orderly and get the away from the closing flaps and you.

What people blame on line dump is almost always not controlling the pack job well enough and ensuring the slider is securely against the stops. The slider is already an inch or 2 down the lines after the bag comes off. Air gets past the slider hits the bottom skin and expands rapidly. Blammo... must be line dump...but it's not.

So, if the primary stow stays closed until line stretch, all is good. The tail pocket is there to aid in orderly pay-out of the lines. If all the lines fall out but the primary stow is intact, you would never know the difference.
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

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Ditto, I'll use a ZP 42 above 210 or so.



Based on what reasoning..?
It inflates quicker?
Less time to line stretch..?
More comfortable opening?

or rather...why wouldnt you use a 46?



I plan to progress to things which require a stowed pilot chute. This allows me to slowly work my way to that and get accurate info on altitudes and time to linestretch on specific objects with a 42 hand held. I have no desire to stow a larger pilot chute. With regards to low stuff, I spend a lot of time and energy on analyzing past jumps and using that data to model future ones. It allows me to get a very good idea of what's going to happen on the jump and therefore I can make an informed decision if the risk is worth it.

The other reason is that for multiway freefalls from below 240, it allows me to more safely open lower than with a larger pilot chute. I can take the same delay with a 42 and be open lower than a 46 with less variance compared to taking a slightly longer delay with the 46. I'm mainly trying to minimize freefall time in these situations, as that will give me a larger buffer with the ground than more freefall with faster openings. Due to my weight, canopy size, line length, etc, the risk is much smaller for me to be the low guy than nearly everyone I jump with.

With all that said, I currently have a 52" ZP PC being built. Also note that nowhere did I say using a 42 will be less risky than a 46/8 on a normal low freefall jump. I believe it to be more risky in that situation.
A waddling elephant seal is the cutest thing in the entire world.
-TJ

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What we perceive as a "hard" opening is basically the maximum acceleration (at any single point) in the opening sequence. If that point occurs because you are being spun around, or surged forward, or pushed backward, it's still the maximum point.



I'm fairly sure you're talking about "jerk." It's da/dt, the change in acceleration with respect to time.
A waddling elephant seal is the cutest thing in the entire world.
-TJ

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"Line dump" won't cause a hard opening on a go and throw. Think T.A.R.D. That's real line dump. (ok, so there's no air speed)



Are you not falling a lot faster on a go and throw by the time the canopy is inflating? Would this not cause a harder opening than a TARD with zero airspeed?

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oh well replying to a tread whith out reading the rest of the posts:ph34r::D

Hookit i dont agree whith you that line dumps wont give a hardopening.

On TARD you dont have a delay and can(SHOULD) control your lines as theyre leaving your hand(look at your hand as a tailpocket).

1 sec delay you have started picking up speed,leaving the lines along the canopy up there whith no control will give a bigger bang than usualy,whith the posibility for dameged at both lines and canopy(mostlikely burn dammegedes).

you could do a simple test.
tie somthing to a line,then hold the line in one hand and let go of the thing,you will feel it as soon as it hit line streach.
now try making some kind of a tailpockect.your test will show that the thing falls slower than test 1.,thats as your hand playing the canopy will hold it back

now look at the thing as you in freefall and the hand holding the line as your canopy...

make sence?

On a real line dump the canopy is inflating above you staying at the same place untill line streach

regulary opening the canopy will be dragged behind you.

I know its not all 100% but the best i can explain..


Stay safe
Stefan Faber

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570: I acknowledged the low airspeed... look in the () of that post.

Faber. Define Line dump.

Line dump is lines being left behind as the canopy is being decelerated.

There is a primary stow that should be secured around a bight of lines properly. Unless the lines are pulled from that stow before line stretch, the opening is not influenced.

Granted, a properly secured pouch will help the primary stow do it's job since it doesn't have a load right away and will not have to carry all the lines to line stretch.

The pouch is to aid in an orderly payout but try not to be fooled that lines falling out of it causes faster openings. Lines pulled from the primary stow may, but not simply from the pouch.

What you are describing is a skydiving bag strip issue. Bag strip is extremely rare. The locking stows on a bagged deployment will hold the bag shut untill the lines are yanked out. The rest of the line stows are there to get the lines off your back and away from the flap.

If some how, the bag is off the canopy before line stretch, the result is likely bad. losing control of the slider while packing is blamed on line dump all the time. Locking stows are important, the rest of the stows are for neatness.

Think of a slider down opening. The bight of line in the primary stow SHOULD contain the canopy to some degree. When the bight is yanked free, the entire bottom skin is allowed to spread out all at once.

If that bight stays secured in primary stow until it's yanked out at line stretch, how is does that make a difference whether the lines stayed in the the pouch or not?

An off heading opening will often yank your body in such a fashion that the percieved opening speed is faster.

If you happen to open, say ... nearly upside down facing the object you jumped off and have to hide your head from the canopy and lines that are passing by, the opening feels rather abrupt when in fact the speed of the opening is normal.

I've been redundantly repetitive enough for now. Time to go make something of the day.

Cheers.
My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

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It's exactly what you said though ;)

I'm shutting this off now so perhaps another time.

Have a good day/night, whatever time it is there.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

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This will be us in a few years ==> Fight


I guess you´ll be the fat guy laying on the asphalt:ph34r::D
No mate if we had that much energy at that point we will be out jumping,you´ll be the one whith loong canopy flights:D

Stay safe
Stefan Faber

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wrong totally wrong Tom. a hard opening is a maxed out DEceleration, not acceleration.

track into a deep brake setting and it will slam you harder than a shallow one.

on a go and throw or deep delay slider down parachutes open really hard and fast even without all the gizmos that you you guys throw into the equation these days. (vents, toxins etc..)


all you guys are thinking WAY too much. if your BASE rig is opening hard stop jumping vents, stop springing for $200 great big pilot chutes. switch to a small mesh slider, roll your nose, double wrap your rubber bands, whatever. try diffferent set ups altering them one at a time.

slider down base rigs open really fast and hard. thats just the deal on any slider down jump, doing aerials can help you not feel the slam so much.

UPH

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Quote: "why is it i never hear about 90 right's there?? it's either 90 left's of 180's and then of course for some reason the 180 turns into "attack of the poison oak". airdog had a fun time with that shit. maybe he'll chime in???"

Of the 73 FF's (no static lines or PCA's so cant speak on that topic) I have from that object, I have had 6 90 rights, 4 90 lefts, multiple sub 90 right/lefts, and 0 180's. I will only use a 46/48 and I have never made a BASE jump with a non-vented canopy (it has to do with what I saw as a student--fuckin nasty).

I dont know about all the technical stuff ya'll talk about, but Hookitt is right, off heading openings both s/u and s/d can give the impression of a "hard" (or harder) opening than you are used to.

jtholmes is also right, stop thinking so goddamm much and just JUMP............just kidding folks, stay safe out there!


Cheers-

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Flik'd a lowish coastal S last night with my Perigee 2/Flik 266 Vtech/46" Toxic PC. 1/2 second delay tops. Exited slightly head high if anything.

Had a violent opening, felt like a 3+ second delay...combined with a 90 left.

Any ideas what could lead to a hard opening with such a short delay???



its a flik...really...i think you should call to Stane...the Man...

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F......ck the Finns !!!
FastPete www.pete.fi email: [email protected]

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a hard opening is a maxed out DEceleration, not acceleration.



It is actually both, because deceleration is just the term for negative acceleration.

http://en.wikipedia.org/wiki/Acceleration

Quote

To accelerate an object is to change its velocity, which is accomplished by altering either its speed or direction (as in the case of uniform circular motion) in relation to time. In this strict mathematical sense, acceleration can have positive and negative values (deceleration).



class dismissed :P
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track into a deep brake setting and it will slam you harder than a shallow one.



Yes, assuming that you have an on-heading opening.

This is because the overall magnitude of the acceleration is less, because the canopy with the shallower brakes is moving faster (and in the same direction as the jumper) than the canopy with deeper brakes.

As a radically oversimplified example: If you are tracking forward at 20 mph, and your canopy opens flying 10 mph in the same direction, your acceleration is -10 mph (you end up going 10 mph slower than you started). If you are tracking forward at 20 mph, and your canopy opens flying at 5 mph in the same direction, your acceleration is -15 mph. The deeper brake setting then gives you a larger change in velocity (i.e. more acceleration).


It's important to remember that acceleration has both speed and direction components, though, so as soon as you're talking about motion in different directions (which is pretty much every real world case), the changes in acceleration become significantly more complex.
-- Tom Aiello

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SnakeRiverBASE.com

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I can take the same delay with a 42 and be open lower than a 46 with less variance compared to taking a slightly longer delay with the 46. I'm mainly trying to minimize freefall time in these situations, as that will give me a larger buffer with the ground than more freefall with faster openings. Due to my weight, canopy size, line length, etc, the risk is much smaller for me to be the low guy than nearly everyone I jump with.
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how many time have you used a 42 on 240 or lower umps ?. If you have any delay or and hesitation from the heights ?. I think not.

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I currently have a 52" ZP PC being built.
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from 42 to 52 why and what hight is the for ?.
"A peaceful heart leads to a healthy body; jealousy is like cancer in the bones ..."

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how many time have you used a 42 on 240 or lower umps ?. If you have any delay or and hesitation from the heights ?. I think not.



20+. yes.

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from 42 to 52 why and what hight is the for ?.



less time to linestretch. sub 180
A waddling elephant seal is the cutest thing in the entire world.
-TJ

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