"Throw" your pilot chute?

[AFFI 0]

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You don't fucking THROW IT!

Bad advice for young impressionable minds.

If you hold the PC even for a second, the bridle (whipping around in a 120MPH wind) can take a wrap around the fabric of the PC and cinch it closed which may result in a PC in TOW. I have seen it, which led to a 2 Out situation.
This lowtimer did not handle the 2 Out very well (as trained) resulting in serious injuries landing.

The reason we teach to "Throw" is to get out of the habit of holding which may introduce a few different bad situations.

If the jumper goes to full arm extension and releases but the full extension is not lateral away from the body, but rather angles upward, close to the burble the PC can easily get sucked right into the burble - I have seen this one as well - have a great series of pic's captured from my camcorder. I will try to find the BU of this pic and post.

Please enlighten me - Teaching not to throw has what advantages?

Mykel AFF-I10
Skydiving Priorities: 1) Open Canopy. 2) Land Safely. 3) Don’t hurt anyone. 4) Repeat…

[brettski74 0]

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I'm not an instructor, nor do I have your level of experience, but I am about to respectfully disagree with you on a couple of points.

You can throw the pilot chute. Just because the relative wind will accelerate it away from you much more rapidly in the vertical direction does not mean that any horizontal speed your arm movement has imparted suddenly disappears. Even if that only gives you an extra 6 inches away from the burble in the time that it screams away from you, that's still an extra 6 inches away from a potential problem.

?

Just in the interests of physics, the drag force is non linear with velocity, which introduces a coupling between the horizontal and vertical components of velocity when determining the drag. So the horizontal drag in this case (opposing the "throw" velocity) is much much larger at a 120mph fall rate than it would be for a static throw. So if you can throw the chute 6ft sideways on the ground, it doesn't mean it will go 6ft sideways when you're in freefall.

Isn't physics fun?

I wasn't suggesting that the drag wouldn't be higher during freefall then when exiting the plane, nor am I terribly interesting in knowing how much further away the PC goes. The fact remains that the horizontal velocity does not magically disappear when we release into the wind. If you release it with some horizontal velocity, it will go further away from you than if you release it at the same point with no horizontal velocity.

[peckerhead 0]

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Bad advice for young impressionable minds.

I disagree, I think telling them to throw it is bad advice.

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If you hold the PC even for a second, the bridle (whipping around in a 120MPH wind) can take a wrap around the fabric of the PC and cinch it closed which may result in a PC in TOW. I have seen it, which led to a 2 Out situation.

I never said you should hold it, even for a second. Full arm extention and immediate release.

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The reason we teach to "Throw" is to get out of the habit of holding which may introduce a few different bad situations.

Who is we? Again, I never once said anything about holding it.

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If the jumper goes to full arm extension and releases but the full extension is not lateral away from the body, but rather angles upward, close to the burble the PC can easily get sucked right into the burble

That would not be the proper technique now would it?

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Please enlighten me - Teaching not to throw has what advantages?

I teach full arm extention and immediate release out into clean air. I have seen many occasions where the jumper simply pulls it out of the pouch and tosses it before the arm is fully extended. That is when you can have the PC go right back into the burble.

A few years back a friend of mine with nearly 1000 jumps had a lazy throw and the PC went right back over his back. It was an older vector container and the bridle hooked under his reserve closing flap. When the PC inflated it busted the closing loop on his reserve which led to a nasty two out. Needless to say he was lucky to survive.

If you "throw" it before your arm is fully extended it will be closer to your burble than it will be if you simply release it at full arm extention. It does not matter how hard you toss it, at terminal it will travel with the relative wind as soon as you release it.

[popsjumper 2]

thanks for your input.

I will continue to teach my students to THROW.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[pchapman 262]

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Just in the interests of physics, the drag force is non linear with velocity, which introduces a coupling between the horizontal and vertical components of velocity [...]So if you can throw the chute 6ft sideways on the ground, it doesn't mean it will go 6ft sideways when you're in freefall.

And the pilot chute doesn't stay quite as nicely rolled and folded up at 120 mph as on the ground, which clearly adds to the drag too.

[kallend 1,647]

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I'm not an instructor, nor do I have your level of experience, but I am about to respectfully disagree with you on a couple of points.

You can throw the pilot chute. Just because the relative wind will accelerate it away from you much more rapidly in the vertical direction does not mean that any horizontal speed your arm movement has imparted suddenly disappears. Even if that only gives you an extra 6 inches away from the burble in the time that it screams away from you, that's still an extra 6 inches away from a potential problem.

?

Just in the interests of physics, the drag force is non linear with velocity, which introduces a coupling between the horizontal and vertical components of velocity when determining the drag. So the horizontal drag in this case (opposing the "throw" velocity) is much much larger at a 120mph fall rate than it would be for a static throw. So if you can throw the chute 6ft sideways on the ground, it doesn't mean it will go 6ft sideways when you're in freefall.

Isn't physics fun?

I wasn't suggesting that the drag wouldn't be higher during freefall then when exiting the plane, nor am I terribly interesting in knowing how much further away the PC goes. The fact remains that the horizontal velocity does not magically disappear when we release into the wind. If you release it with some horizontal velocity, it will go further away from you than if you release it at the same point with no horizontal velocity.

I doubt you have a shred of emprical evidence to support that statement, and there is certainly no theory to support it. Fluid dynamics is a complex science and turbulent flow is very poorly understood.

...

The only sure way to survive a canopy collision is not to have one.

[skyberdyber 0]

I was so excited when I read a post of Tom's I fully agree on. We are usually at odds for some reason. I agree with everything he said here and I would like to add something.
There are pictures out there of tandem drogue throw with the packed drogue 6-8 feet from the TI after a good throw. Although not as dense, if a pilot chute is packed up correctly and the throw is hard enough, it is possible to get quite some clearance out of the pouch before it begins to unfurl.
A lot of jumpers tend to have lazy throws cause they don't believe it matters. Many that have been jumping for any length of time will tell you they have had the P/C go under their wrist at some point because they got lazy. I have done it myself.

http://www.skydiveatlanta.com
http://www.musiccityskydiving.com

[rehmwa 2]

On a side note I do think it's a good idea to tell someone on transition to a throw out that they should throw "out to the side" and not blithely say "throw it into the wind".

"into the wind" could be misunderstood as upwind (or down )

some students can be more literal and not think in return........

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[brettski74 0]

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I doubt you have a shred of emprical evidence to support that statement, and there is certainly no theory to support it. Fluid dynamics is a complex science and turbulent flow is very poorly understood.

I don't have any empirical evidence to show the path of a PC after release in varying situations, however, the statement that the pilot chute's horizontal velocity does not magically disappear is well supported by Newtonian physics. It takes time for the horizontal component of the throw to be countered by any force that does so. I can't say that there won't be some kind of turbulent flow which might provide a larger toward-body force in one situation than the other, but:

but inertia, the weight of the handle and the influence of the bridle is likely to maintain a PC attitude similar to a track or slide forward and out from the body

while the bridle is still unfurling, it's less likely to impart inward forces due to tension on the bridle, however, after the short delay required for it to become fully horseshoed, the tension on the bridle is likely to draw it back closer to the body

This is only theory, but we could test this theory using video of a number of deployments taken from a moderate distance in front of the deploying skydiver. Anyone game?

[billvon 2,427]

> I doubt you have a shred of emprical evidence to support that statement . . .

I have some observational evidence. Hard throws result in more separation between PC and jumper. The handle has a lot to do with it - hackeys travel a lot farther than PVC handles, but hackeys also make the PC do some slightly odd things sometimes (like not inflate until it gets halfway to bridal stretch.) I think it's due to the weight of the thing holding the apex down while the rest of the PC decelerates.

[D22369 0]

I will continue to teach my students to THROW.

***

I also see no benefit in changing from throwing to dropping.. and will continue to teach them to throw it.

Roy

They say I suffer from insanity.... But I actually enjoy it.

[peckerhead 0]

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thanks for your input.

I will continue to teach my students to THROW

Good for you! I will continue to teach the tried and true method I have taught for over 20 years. Without incident I might add....

The ironic thing about this whole thread is I most likely teach the exact same thing my detractors do....

We just use different terminology.

[RippedCord 0]

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...the horizontal drag in this case (opposing the "throw" velocity) is much much larger at a 120mph fall rate than it would be for a static throw. So if you can throw the chute 6ft sideways on the ground, it doesn't mean it will go 6ft sideways when you're in freefall.

Isn't physics fun?

Nifty! I learned something today.

...and yes it is.

AMDG

[mdrejhon 8]

I think millimeters make a difference. If you throw it -- that extra few millimeters is increased chance it will catch wind, and less chance it will bounce back into the burble. Less chance of tangling with your hand.

Of course, just letting the wind rip the thing out of your hand often works, but it's best to try and throw it -- (n a brisk throw that's not too aggressive as to cause you to destabilize your position during deployment.)

WARNING: Physics 101 Talk below
Around the time I got my B, I once tested the PC by holding it for 1 second before letting it go (yes, a dangerous thing to do in retrospect, because of the bridle - and yes, I posted about it almost two years ago - don't do this), and the force was pretty light because it hadn't inflated. (It was a preplanned event with a higher pull altitude) Anyway, the fact I was able to hold onto the PC and it wasn't inflating while I held it, gives more evidence to the fact that throwing is beneficial, at least in a "safety margin" perspective, since the PC doesn't always inflate instantaneously if I am still holding by the handle. If I let go as is, it would take a finite (small) time for the PC to right itself (handle down to handle top). Odds are is it will fall into my burble before it "righted itself" and I might even get a PC in tow because it wasn't inflating fast enough (especially if it's a marginal PC). I figure that throwing it makes it flip the correct way up more quickly, because it will go outwards at least a few centimeters, inches (i.e. 3 inches out and 6 feet upwards), as it goes from hand to bridle stretch. Baseball throwers can throw almost 100mph, I'm probably only throwing at 20mph outwards, max. Mathematics show that's a few inches of outwards even at 20mph OUT, 120mph UP (due to momentum, even slight, it's actually an acceleration from 0mph relative to my body to some big mph relative to my body (until bridle stretch)). That's not a straight line upwards. And yes, I realize if the PC inflates, the 20mph of outwards horizontal momentum will be nearly instantaneously stopped by the air resistance of the fabric of an inflated PC (much as it accelerates very quickly upwards by the relative wind). But, in the tiny chance, the PC doesn't inflate yet, the horizontal momentum if hackey will be more unimpeded by the relative wind (Because of less resistance caused by a non-inflated PC) and the momentum of the hackey will keep it going outwards more easily and longer before bridle stretch, since more horizontal momentum is preserved by the initial throw. As this cause the PC to keep going further horizontally away from your burble, it makes it more likely to catch burble-free air, and inflate a few fractions of a second faster (and occasionally means the difference between good canopy and a PC-in-tow, especially when we're talking about a marginal PC situation) And we all know how fractions of seconds matter in high velocity sports, not just skydiving. It's just common sense physics 101 and mathematics.... momentum, air resistance, acceleration, velocities, all playing an intricate game of inflating your PC to save your life in your fall. And in some of the videos you see, for a relaxed non-sliding arch, you can see the PC line is sometimes slightly diagonal, in the throw direction -- just very slightly, if you look carefully.
So there's more evidence, as you can see. And sometimes in a hesitation situation the PC swings back and fourth before it opens - the throw will help impart enough horizontal energy to eventually cause the bridle to swing left/right slightly at stretch if it hasn't properly inflated by bridle stretch, giving it more chance to catch air beyond the burble, especially if one happened to maybe pack a little tighter than usual. Of course, some of the above this is speculation mixed with facts - but it does make logical sense that throwing adds some extra "safety margin"... (a brisk, controlled throw - a good one, not hurriedly as to destabilize your bellyfly: So you don't throw it too hurriedly and then go into linetwists because you became unstable at pull time). Sure, one can survive by just letting go, but why take the chances - not all of our PC's may be as good as yours...

(No reserve rides. A couple of minor fraction-second hesitations that only made me "hmm, that's a bit slower than usual" which I remember DID occur when I did a couple of lazy throws. Even though it may not necessarily be the lazy throw, there seems to be a vague correlation, at least when it comes to an old collapsible PC. It's one of those things "hmm, these tiny hesistations seem to happen more when I do lazy throws"... Anyway, my PC's now replaced. Knock on wood.)

[pchapman 262]

To go to silly extremes, if we really wanted to throw the PC a lot further we'd need better pilot chute deployment staging.

Put the PC in its own little cylindrical bag or diaper with a lock at the mouth, to keep it's drag low, while it is being propelled outward by the momentum of a deliberately heavy hackey. Sort of like what's done for a mortar-deployed ultralight recovery parachute, or some staging chutes on ejection seat systems.

Or if you don't like the heavy hackey idea, we need an even smaller pilot chute to extract our pilot chute, ad infinitum... (Ignoring scale and viscosity effects...)

[AFFI 0]

The OP is spot on concerning his perspective relating to the benefits of “Throwing” (at least in my simple uneducated mind, what the hell are Physics?).

In my limited experience, from what I have learned from the very experienced AFFI mentors I was lucky enough to have teach me, teaching students to “Throw” reduces the likelihood that they will hold on to it, even if only for a moment.

I have a video of a student jump where the student pulled out the PC held onto it, looked over his shoulder and thinking he had a total deployed his reserve. Once he saddled in under his reserve he stuffed the PC in his shirt and landed without further incident. It was enough to really rattle a very good and experienced AFFI.

I also witnessed a low timer just off student status hold the PC for just a moment - the bridle took a wrap around the PC cinching it close, he fired his reserve in response to a PCIT (as he was trained), then got a 2-out but did not respond as trained and rode a downplane into the ground.


So concerning solo freefall student training, I was taught to teach a vigorous yet controlled “Throw” in order to minimize the chance of a similar situation occurring. The extra 10 minutes of training on the ground “Throwing” is worth it but sill, every now and then student would still hang onto it. So I had to ask myself how I was being ineffective in my ground training and failing my students.

I fixed it by promising them that if they hold it even for a moment that they are gonna get punched right in the ribs as hard as I can (not my idea, one of my mentors who is an IE) and ever since, NOT ONE SINGLE student has held onto it, not even for a moment..

So I agree with an respect the OP’s opinion and reasoning . But the simple reason I teach students to “Throw” is as simple as that and this method seems to be tried and true based on the results I have gotten.

Deployment time is not a good time to have issues with a student and I am sure other teaching methods work as well.
-

Mykel AFF-I10
Skydiving Priorities: 1) Open Canopy. 2) Land Safely. 3) Don’t hurt anyone. 4) Repeat…

[AFFI 0]

There was some PC in burble talk in this thread

A series of pic's of a PC being "let go" into a burble is posted here (did not want to double post)...
Sure is is not "proper" form, but how many students use proper form anyway?

After this I taught him to "Throw" and it fixed his bad form...

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2735092#2735092

-

Mykel AFF-I10
Skydiving Priorities: 1) Open Canopy. 2) Land Safely. 3) Don’t hurt anyone. 4) Repeat…

[kkeenan 13]

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...it is being propelled outward by the momentum of a deliberately heavy hackey. Sort of like what's done for a mortar-deployed ultralight recovery parachute, or some staging chutes on ejection seat systems...

That is the exact reason for a heavy hackey. The mass propels it out into the clean airflow. The lighter, "whiffle ball" type handles do not do this.

Kevin

_____________________________________
Dude, you are so awesome...
Can I be on your ash jump ?

[Para5-0 0]

Another important point is that their was a transition from PULL (ripcord)to Throw (pilot chute).....back when we had spring loaded pilot chutes in student rigs students were taught to pull and hold onto the ripcord. Unfortunately, when the student pulled the pilot chute and held on to it, it did not make for a fun AFF jump. I think "throw" is not only better terminology for a student now, but helped to eliminate or reduce students holding onto the pilot chute. Ged rid of it like a live grenade....
Hence, TM's for training tandems should instruct students to pull the ripcord and continue with a throwing motion so we do not form bad habits early,that aff's will have to break over the next several jumps.

[popsjumper 2]

"Hence, TM's for training tandems should instruct students to pull the ripcord and continue with a throwing motion so we do not form bad habits early,that aff's will have to break over the next several jumps. "

Ooooooo...good stuff. I'll bring it up to our TIs today. We have a couple on Tandem progression right now.

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239

[padalcek 9]

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That is the exact reason for a heavy hackey.

hence - the frog.
right?

[whisper] maybe you should upgrade to flying squirrel. [/whisper]

Padalcek - CCO, HF-17
http://www.theflyinghellfish.com
I'm not a real skydiver - but I do play one on dz.com.

[brentcair 0]

O.K. I'm convinced.
New deployment count
Arch, Reach, Extract to full arm extension and release, arch

Duhhhhh

[AFFI 0]

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O.K. I'm convinced.
New deployment count
Arch, Reach, Extract to full arm extension and release, arch

Let us know how long it takes for a student to hold it and not release it right away.
-

Mykel AFF-I10
Skydiving Priorities: 1) Open Canopy. 2) Land Safely. 3) Don’t hurt anyone. 4) Repeat…

[peckerhead 0]

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O.K. I'm convinced.
New deployment count
Arch, Reach, Extract to full arm extension and release, arch

I teach arch, reach, pull

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Let us know how long it takes for a student to hold it and not release it right away.

The student should never "hold" it. Full arm extension and immediate release into clean air.

The most important thing is to get it out as far away from the burble as possible before the release In one swift motion!

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[billvon 2,427]

>The student should never "hold" it.

True. Indeed, the whole pull should be a smooth process. However, I'm sure you've seen students do things slowly (in steps) and/or "stall" at one step in the process. If the process is arch, reach, extract, release, they may stall at the extract step.