Freefall vs Under canopy

[Groundbound 0]

if you hate newbie posts, ignore this one.

What makes divers decide how to distribute their available time?
Is it simply that some like the rush of freefall, so they leave it packed until late in the descent? And others prefer the ride/view/time aloft that a canopy ride provides?
Safey considerations aside, it seems like there is a choice here for fairly high altitude drops.
Surely if there is a big wind aloft, you can't pop it out right away either.
Thanks

[PhreeZone 15]

High winds at altitude? Cross county jumps!

Jumpers split it how ever they like to. Some like canopy flight so they pull higher. Others like the freefall so they pull at normal altitudes.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[DrewGPM 0]

I am all about the cross country jump. Especially at sunset...what a way to close out a great day fo freefall! I take an insulated bag with me...filled with dinner and a drink. Nothing better than a nice burger at 12,000 feet!

I love the freefall, but nice long canopy ride helps me unwind from the adreneline filled day.

[Groundbound 0]

looking at the high number of fatals from malfunctions, and those that were not corrected in time, or not cut away in time, I am going to ask my instructor on my first tandem to pull as soon as possible. "Time can be a lifesaver"(?)
When I ski, I like to take the hill slowly, prolong the ride. I can zoom to the bottom and spend all my time on the lift but.... what fun is that??!

[mattjw916 2]

Quote

"looking at the high number of fatals from malfunctions..."

"High" number of tandem fatalities!!? Um, not on this planet dude... they are few and far between. Tandems pull at ~5k+, which leaves TONS of time to attempt to clear a mal and/or chop it. If one happened, chances are you wouldn't even know it anyway.

NSCR-2376, SCR-15080

[JonBonGraham 0]

Where are you getting these stats from?
Like has been said, tandems pull at around 5k (usually), wheras experienced jumpers generally pull at 2.5-3.5k. Pull at 5k and if nothing opens above your head you've got about 25 seconds until you impact (assuming your drogue's out), with more time if you have a partial mal since all that fabric will be slowing you down. Take a look right here on DZ.com and you'll see that only 1/3 of fatalities arise from malfunctions/reserve problems - the main killer in this sport is probably (unfortunately) experienced jumpers doing low turns.
Tell your concerns to your tandem instructor just after your training (maybe the training will answer some of your questions) and see what he says.
Anyway, experiencing terminal velocity is half of what tandem skydives are about, so just enjoy it!

Durham University Freefall Club

Grounds For Divorce website (band I'm in)

[skybytch 259]

Quote

Anyway, experiencing terminal velocity is half of what tandem skydives are about, so just enjoy it!

You can't experience terminal velocity under a drogue.

[Praetorian 1]

Quote

You can't experience terminal velocity under a drogue.

(nitpick and tease) of course you can "terminal velocity " is just the point where the drag on an object equals the pull of gravity. A slip of paper dropped whole or crumpled will reach terminal velocity, it will just reach it sooner (and slower) uncrumpled. (end nitpick and tease)

Good Judgment comes from experience...a lot of experience comes from bad
judgment.

[Groundbound 0]

Quote

Quote

"looking at the high number of fatals from malfunctions..."

"High" number of tandem fatalities!!?

You posted my quote, and then replied to something else, something imagined.

I did not ever say "High number of tandem fatalities".
That is your statement.

I think you added the two thoughts, one being the higher percentage (30% or 24/79 fatals according to http://dropzone.com/fatalities/) of malfunction fatalities to my other comment about my preference for my own first tandem jump, to come up with your sentence "High number of tandem fatalities" which I did not way nor meant to imply.

JonBonGraham. has taken your misquote and run with it now, this is how rumors start!

Anyway, now that the air has cleared, back to the topic at hand.... do you folks think it adds any safety to have a canopy open as soon as possible after jumping?
Maybe there are risks with having it open for too long?

Thanks for helping a newbie to the sport.
I remind all that I am in search of a website for completely inexperienced but interested people to become acquainted with skydiving... if this is not it, tell me where to go (or to just go away!)

[wmw999 2,168]

Quote

What makes divers decide how to distribute their available time?

A combination of risk factors.

Opening your main high leaves you with a much greater possibility of landing off the dropzone (because we don't map all the winds all the way down), and of losing your main (which, while not unsafe, is very expensive).

Opening your main really low is a bad alternative, for very obvious reasons.

Opening high when others are out after you opening lower can lead to their being too close to you in freefall when you're already under canopy. That's really really bad, too.

Some people prefer their mains to open very softly; this takes more time, and they open higher most of the time. Other people prefer a main that opens a little quicker, to give them more time.

The upshot is that opening altitude is one of a set of factors that helps with safety. Being practiced in emergency procedures (so that they're automatic, with good judgement) is probably more important than extra altitude.

A tandem jump will involve the tandem master opening quite a bit higher than the average freefall jump. Tandem emergency procedures are more complex, and tandem masters take that responsibility extremely seriously. If you'd rather he (or she) erred on the high side, let him know. And you can tell the DZ owner that you're nervous, and would really prefer to work with an extremely experienced tandem master.

Good luck. Skydiving is not safe. We manage risks, maximizing the safety as much as possible, balancing skills against our desired risk level.

If it were completely safe, plenty of skydivers wouldn't be doing it.

Wendy W.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[Groundbound 0]

Thank you so much for that info Wendy, it really helps me to understand.

Only comment I will make is that several people have posted to the effect that skydiving has some risk and I need to live with it or something like that. I am in full agreement and have no problem with that. I am not asking questions to get someone to admit its a risky sport, or to tell me how to avoid any chance of being killed in this sport. I know how it works. You sit at home at the TV, you will never have a chance of being killed by such things. Life may have no meaning but that is how some people like it!
I am just here to ask and learn, to find out what its all about, to find out how to minimize and manage my accepted risk level.
Dave

[PhreeZone 15]

There is an absolutly wonderful book out there called JUMP! that I would highly recommend reading at this stage of your interest. It will answer questions you never even would think to ask.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[JonBonGraham 0]

Quote

Quote

Quote

"looking at the high number of fatals from malfunctions..."

"High" number of tandem fatalities!!?

You posted my quote, and then replied to something else, something imagined...

I did not ever say "High number of tandem fatalities"...

JonBonGraham. has taken your misquote and run with it now, this is how rumors start!

Looks like there's some confusion here:
1) While Matt did take your quote about fatality rates and mistake it with a comment about tandem fatality rates this is sort of understandable, because you say (and I'm paraphrasing here) "Mals cause a lot of fatalities, thus I want my TI to pull higher".
2) I wasn't running with this, I was making comments about general fatality stats.


Aaaaaaaaaaanyway...
skydiving is all about weighing up risk vs. reward.
Doing your tandem jumping with your instructor pulling as high as, for example, 10k, I suppose you might have less of a chance of getting a mal that'll kill you, but only very, very slightly - we're talking one in a million here - but you've got more chance of strong upper winds carrying you away from the DZ and having to land off, which can lead to injury or worse. On the other hand, the reward you get for doing the jump decreaces dramatically, since you'll get less freefall time and will probably have not as comfortable a ride down because you'll be cold, have a higher chance of landing off, having to sit in the harness for a longer period of time, etc.

Oh, and this is a forum for jumpers and non-jumpers of all experience levels, you don't have to go anywhere else, and don't feel you can't ask questions that you think might be stupid.

Quote

There are no stupid questions in this sport, only stupid answers!

And about your jump - I can't stress how important it is to properly talk through this with your tandem instructor on the ground before you go up. Take the advice from the instructors on this forum, but take his/her advice as final since at the end of the day he/she will be the one saving your life!
Hope you enjoy your tandem when you come to do it!

Durham University Freefall Club

Grounds For Divorce website (band I'm in)

[JonBonGraham 0]

Quote

Quote

You can't experience terminal velocity under a drogue.

(nitpick and tease) of course you can "terminal velocity " is just the point where the drag on an object equals the pull of gravity. A slip of paper dropped whole or crumpled will reach terminal velocity, it will just reach it sooner (and slower) uncrumpled. (end nitpick and tease)

Ah... now's where you can get really nitpicky and reeeeely geeky by saying that an object will never (or only very, VERY rarely) reach it's terminal velocity. Model it mathematically and you'll see that you never reach a terminal velocity, but instead approach it and get nearer and nearer, but you'll technically always be accelerating.
However, during a tandem I suppose it's not technically "freefall" as you've got the drogue slowing you down. But that's for another thread, I'll stop hijacking this one...
[/nitpick][/geekiness][/hijack]

Durham University Freefall Club

Grounds For Divorce website (band I'm in)

[kallend 1,678]

Quote

Quote

Quote

You can't experience terminal velocity under a drogue.

(nitpick and tease) of course you can "terminal velocity " is just the point where the drag on an object equals the pull of gravity. A slip of paper dropped whole or crumpled will reach terminal velocity, it will just reach it sooner (and slower) uncrumpled. (end nitpick and tease)

Ah... now's where you can get really nitpicky and reeeeely geeky by saying that an object will never (or only very, VERY rarely) reach it's terminal velocity. Model it mathematically and you'll see that you never reach a terminal velocity, but instead approach it and get nearer and nearer, but you'll technically always be accelerating.
However, during a tandem I suppose it's not technically "freefall" as you've got the drogue slowing you down. But that's for another thread, I'll stop hijacking this one...
[/nitpick][/geekiness][/hijack]

To be really geekier still, TV decreases as air density increases, so you do in fact reach it at (at least) one point on the skydive as you go from speeding up to slowing down again.

From the physics viewpoint, what is the difference between a drogue and a really loose big jumpsuit?

...

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

[skybytch 259]

Quote

of course you can "terminal velocity " is just the point where the drag on an object equals the pull of gravity.

Okay. My bad. I should know better than to talk about things I don't understand... like physics.

If you ever get a chance to do it, tandem terminal - i.e. the terminal velocity of a tandem pair without a drogue - is quite an experience.

[PhreeZone 15]

I have went tandem terminal once. Very wicked... I had to do it to get my rating.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[Mixoligist 0]

Tandem terminal is Heavy duty.....not my favorite.

..................................
Better you than me
..................................

[DrewEckhardt 0]

Quote

if you hate newbie posts, ignore this one.

What makes divers decide how to distribute their available time?
Is it simply that some like the rush of freefall, so they leave it packed until late in the descent? And others prefer the ride/view/time aloft that a canopy ride provides?

When you want to play with parachutes, opening right out the door gives you much more time tha you'd get if you mixed freefall into the equation. Getting your own low pass with like minded people also means the landing area will be less crowded.

Otherwise people open as low as practical. There are technical limits - if you have a main that snivels for a long time you don't want to risk snivelling past AAD firing altitude if you pull a bit lower than planned. IIRC USPA recommends an 1800 foot cutaway decision altitude - you can add how far it takes to open on top of that, a little padding, and have a opening altitude. There are traffic concerns - if you open higher you have more time to let other people land so you have more room. Conversely if your group is out first you may be better off opening lower and beating everyone down. Spotting at some dropzones is bad and opening higher may mean the difference between walking to the hanger or climbing fences and hitching rides. How much housekeeping you need to deal with on opening and the potential for time consuming problems can be an issue - with four zippers, legs that need to be stowed, a greater likelyhood of problems, and more trouble dealing with line twists wingsuit pilots often like to open at 4000-4500 feet.

With a lot of traffic, slow opening canopy, and potential for a bad spot 3000' is a nice minimum.

With no traffic, a quick opening canopy, and large canopy that will be more affected by winds the 2000' BSR minimum is better.

If the parachute opens real fast and you're doing a hop-and-pop, your body will have less wear and tear if you open out the door whetever that is - 2500 or 4500 feet.

[Groundbound 0]

ph-z, thank you very much for the book idea!
jbg, I thank you for your friendly reply and for putting both the stats and the high-pull into perspective. And not the least, for encouraging my questions.
and DE, the comments helps me understand the issues involved for each, early and late deployments.
You guys are the best.

[JonBonGraham 0]

Quote

Quote

Quote

Quote

You can't experience terminal velocity under a drogue.

(nitpick and tease) of course you can "terminal velocity " is just the point where the drag on an object equals the pull of gravity. A slip of paper dropped whole or crumpled will reach terminal velocity, it will just reach it sooner (and slower) uncrumpled. (end nitpick and tease)

Ah... now's where you can get really nitpicky and reeeeely geeky by saying that an object will never (or only very, VERY rarely) reach it's terminal velocity. Model it mathematically and you'll see that you never reach a terminal velocity, but instead approach it and get nearer and nearer, but you'll technically always be accelerating.
However, during a tandem I suppose it's not technically "freefall" as you've got the drogue slowing you down. But that's for another thread, I'll stop hijacking this one...
[/nitpick][/geekiness][/hijack]

To be really geekier still, TV decreases as air density increases, so you do in fact reach it at (at least) one point on the skydive as you go from speeding up to slowing down again.

From the physics viewpoint, what is the difference between a drogue and a really loose big jumpsuit?

Well, if you're gonna go there...
I see your point about changing air density, didn't think of that one; but that would only really happen if a skydiver kept the same body position at least until this happened - we all know that a slight change in a skydivers' body can change his/her terminal velocity dramatically. So a jumper exiting with a body position that has a TV of 130mph will approach this for a while, if they suddenly change this body position at the right time to one that gives them a TV of 120mph then they will be approaching their TV "from above" (ie. from a faster speed, not a higher altitude!) and will tend towards this for a while until they change thier body position again. If we assume that every skydiver changes thier body position frequently over the course of a skydive then the skydiver will be continually approaching different TV's, but never really getting there, with the exception of if they were to exit with a body position that would give them a TV of 130mph, and then only change that to a body position that gave them a TV of 120mph when they reach exactly 120mph.
Anyway, that was my reasoning. This is what I'm doing my 3rd year project in, so any input/debate you/anybody else has on this would be much valued - if you think this is going to hijack this thread any more though, please PM me!

As for the drogue/jumpsuit thing I think it's not a physics thing; terminal velocity will apply to you whether you're naked, wearing a really baggy jumpsuit, using a drogue or even under canopy, I'd say it's more about the definition of the word "freefall". Looking critically at the definitions taken from dictionary.com:

free fall or free-fall (frfôl)
n.
1. The fall of a body within the atmosphere without a drag-producing device such as a parachute.
2. The ideal falling motion of a body that is subject only to the earth's gravitational field.

You could count a baggy jumpsuit as a "drag-producing device" but a drogue certainly is specifically intended to produce drag, wheras according to (2) none of us are ever in "freefall" except for the very first instant of a skydive from an object/a balloon or similar.

I like debate like this - does anyone else think that is wrong?

Oh and groundbound, no problem; hope you have a blast

Durham University Freefall Club

Grounds For Divorce website (band I'm in)