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Will a bag lock slow you down or increase your speed?

 

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hackish  (No License)

Nov 15, 2007, 11:38 AM
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Will a bag lock slow you down or increase your speed? Can't Post

If the baglock has sufficient drag to stand you up from a stable flat position then it must be applying a fair amount of force to your body. I believe by definition that amount of force sufficient to stand you up would cause you to decelerate, not accelerate even if you were presenting a smaller aerodynamic drag. I haven't spent too much time thinking about all the ifs and buts so this is what my instinct says. It could be entirely wrong.

As for the AAD's data I do believe it could help out here. Any time you're dealing with unknowns the more data available the better.

-Michael


(This post was edited by PhreeZone on Nov 19, 2007, 7:38 AM)


murphyka  (C 34944)

Nov 15, 2007, 12:22 PM
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

I'm interested to know how you think that the data is going to help here other than to just satisfy your interests. Do you really expect to learn somthing from it that you are going to be able to apply to your list of emergency procedures? I'm really curious how it could possibly help?


dragon2  (D 101989)

Nov 15, 2007, 12:37 PM
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
If the baglock has sufficient drag to stand you up from a stable flat position then it must be applying a fair amount of force to your body. I believe by definition that amount of force sufficient to stand you up would cause you to decelerate, not accelerate even if you were presenting a smaller aerodynamic drag.

Crazy

Hope for your sake you never have to depend on your "theory".

Pirate


peckerhead

Nov 15, 2007, 12:37 PM
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Re: [murphyka] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
I'm interested to know how you think that the data is going to help here other than to just satisfy your interests. Do you really expect to learn somthing from it that you are going to be able to apply to your list of emergency procedures? I'm really curious how it could possibly help?

It is imperative that we study the details and outcome of this incident to prevent it from happening again

It would be a dis-service to the deseased if we did not do so. I know it is hard but please either bear with it or don't read.

Unsure


Edit to add: I am sorry if that came off harsh. Unsure




(This post was edited by peckerhead on Nov 15, 2007, 12:44 PM)


CSpenceFLY  (D 25252)

Nov 15, 2007, 3:26 PM
Post #5 of 73 (4991 views)
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
If the baglock has sufficient drag to stand you up from a stable flat position then it must be applying a fair amount of force to your body. I believe by definition that amount of force sufficient to stand you up would cause you to decelerate, not accelerate even if you were presenting a smaller aerodynamic drag. I haven't spent too much time thinking about all the ifs and buts so this is what my instinct says. It could be entirely wrong.

As for the AAD's data I do believe it could help out here. Any time you're dealing with unknowns the more data available the better.

-Michael


Please speak to one of your instructors before you jump again. It might save your life.


tree102678  (Student)

Nov 15, 2007, 9:44 PM
Post #6 of 73 (4771 views)
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Re: [CSpenceFLY] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

I may be a newbie and all, but I would have to agree with Spence on that one. Drag or no drag.....a Baglock would more than likely stand you up vertical so you would be indeed freefalling faster than the good ol' belly to earth position. Just my 2 cents.

By the way, I don't guess there would be any way of knowing at what altitude Scott actually initiated his main deployment sequence.....is there?




Blue Skies :)


Premier billvon  (D 16479)
Moderator
Nov 15, 2007, 10:02 PM
Post #7 of 73 (4762 views)
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Re: [murphyka] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

> I'm interested to know how you think that the data is going to help
>here other than to just satisfy your interests.

If the cypres fired at 700 feet, and the reserve took 600 feet to open, then there may have been an additional hesitation caused by body position, reserve fouling with the main and/or poor extraction angle for the reserve. Might suggest what a slow reaction to a baglock can do, and/or the dangers of firing a reserve feet-to-earth.

If the cypres fired at 150 feet, then the jumper may have been below activation speed due to the baglock, or there may have been a problem with the cypres. Studying the data might tell us which. Or it might not, but in such cases better too much information than too little.


peckerhead

Nov 15, 2007, 10:57 PM
Post #8 of 73 (4745 views)
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Re: [peckerhead] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
In reply to:
I'm interested to know how you think that the data is going to help here other than to just satisfy your interests. Do you really expect to learn somthing from it that you are going to be able to apply to your list of emergency procedures? I'm really curious how it could possibly help?

It is imperative that we study the details and outcome of this incident to prevent it from happening again

It would be a dis-service to the deseased if we did not do so. I know it is hard but please either bear with it or don't read.

Unsure


Edit to add: I am sorry if that came off harsh. Unsure


This incident is so disturbing for us because a rescue might have prevented a fatality. I think the events leading up to this is very, very important but we still need to have a system in place to care for people who don't land whole.

An older jumper with health concerns would likely be looked for. But a young healthy guy can and did get overlooked.

Come on folks, lets learn from this and never let it happen again.


More later,

What a fucking bummer!






(This post was edited by peckerhead on Nov 15, 2007, 11:05 PM)


hackish  (No License)

Nov 18, 2007, 6:57 PM
Post #9 of 73 (3794 views)
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Re: [murphyka] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
I'm interested to know how you think that the data is going to help here other than to just satisfy your interests. Do you really expect to learn somthing from it that you are going to be able to apply to your list of emergency procedures? I'm really curious how it could possibly help?

Perhaps something could be learned. Perhaps there would be a blip in the descent rate when the jumper tossed. If we found that very close to the activation altitude it would go a long way toward explaining the details we do know at this point. Then it might be a low pull and not a baglock.

I would venture to say that in my opinion ignoring a source of data like that would be irresponsible. Get the data then decide it can't possibly help but don't ignore the data before reviewing it.

-Michael


hackish  (No License)

Nov 18, 2007, 9:30 PM
Post #10 of 73 (3720 views)
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Re: [CSpenceFLY] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
In reply to:
If the baglock has sufficient drag to stand you up from a stable flat position then it must be applying a fair amount of force to your body. I believe by definition that amount of force sufficient to stand you up would cause you to decelerate, not accelerate even if you were presenting a smaller aerodynamic drag. I haven't spent too much time thinking about all the ifs and buts so this is what my instinct says. It could be entirely wrong.

As for the AAD's data I do believe it could help out here. Any time you're dealing with unknowns the more data available the better.

-Michael


Please speak to one of your instructors before you jump again. It might save your life.

Wow I feel like I'm being patronized. However nobody was able to add to what my instincts had said so I took some initiative to research a little further. I'm not trying to be an ass, I'm just not convinced that you fall faster with a baglock.

Poynter I P 341 gives a chart of common drag forces at 120mph. Most are antique but I couldn't find anything published and more recent. A grabber 30" exerts 121lbs of drag force. A wonderhog (aka vector) hand-deploy put out 128lbs of drag. With ZP pilot chutes they are smaller but I suspect the pull forces will be similar.

I did some searching and found that mjosparky had tested a 27" ZP PC and maxed out a 100lb scale at 95mph.

Now it is probably obvious why I feel that a baglock will slow a freefaller down... So the PC is out, pulls the bag up but it remains closed. Putting anywhere between 100 and 140lbs of pull on the bad and jumper - I can see that standing them up.

In head-down position let's assume you go 180mph and belly to earth you go 120. That is a 60mph change. Apply 100lbs of drag to you. I'm fairly confident that the 60mph change just became a negative number.

As I said originally I may be entirely wrong but the figures I've found here seem to support my position. Can anyone add anything to this discussion?

-Michael


Jumpah  (D License)

Nov 19, 2007, 4:03 AM
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

 
http://www.dropzone.com/...ck%20faster;#1501667

In the post by Riggerrob: "A bag lock falls as fast or faster than belly fliers (120 mph). Jump Shack proved this more than 20 years ago with photos of test jumps." Perhaps check those two sources out for more info.


(This post was edited by Jumpah on Nov 19, 2007, 4:04 AM)


chriswelker  (D 19678)

Nov 19, 2007, 5:18 AM
Post #12 of 73 (3588 views)
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

You will be going faster with a bag lock. It is a HIGH SPEED mal.

Hey you may have made a new skydiving discovery.

I would like to see you put your money where your mouth is. Why don't you get with Billy Weber so he can set the perameters of the mal up, you jump it then come back and share your findings with the forum.

If you would like to put some money on the deal I'll bet ya $1000 you will be going faster.

Chris


freeflysteve  (D 102080)

Nov 19, 2007, 6:45 AM
Post #13 of 73 (3502 views)
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Re: [chriswelker] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

If as seems to be general opinion that a bag lock speeds you up on the basis it stands you up or at least could would a piloy chute in tow speed you up or slow you down.
My feelings are the pilot chute in tow because of its placement would slow you down similar to a tandem drogue.
Probably should be a question in gear and rigging but thought i would ask anyway.
Doubt we will ever know what did happen all we can pray for is for Scotts family and the hope he didnt suffer for too long.
Steve


hackish  (No License)

Nov 19, 2007, 7:07 AM
Post #14 of 73 (3471 views)
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Re: [freeflysteve] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

Is it possible to get a mod to split the baglock speed portion of the discussion off and move it to gear and rigging? I'm interested in knowing more about it but it does wander away from the direction of this thread.

As for the PCIT situation I'd agree with what you think. Most feel the "standing up" from a baglock will cause the resulting speed increase. I don't have enough aerodynamic knowledge to answer that question but from my understanding it will be the main difference between the two situations.

I've had a little discussion about the effect of the burble on the PC drag but without real world tests it's pretty hard to evaluate.

If I were a rigger B with a few thousand jumps and time to burn I'd love to hook up a PC as a tandem drogue to evaluate the drop in fallrate. I'd love to hook up a fake baglock on the front rings of a tandem rig to figure out the fallrate of a baglock situation. Unfortunately some of these things can really only be answered by researchers in the field.

-edit reworded for clarity-

-Michael


(This post was edited by hackish on Nov 19, 2007, 7:19 AM)


AFFI  (D 25538)

Nov 19, 2007, 7:25 AM
Post #15 of 73 (3439 views)
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
some of these things can really only be answered by researchers in the field.
And they already have been.

You are correct, you should go do some searches and you will find that these topics have been discussed ad nauseam in past years in other threads

This particular thread is to discuss a fatal accident.


Premier PhreeZone  (D License)
Moderator
Nov 19, 2007, 7:45 AM
Post #16 of 73 (3411 views)
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

I have split this off the Spaceland fatality thread as best as I can. There are some ophan posts in here that I could not leave but this is the best that the software would let me with out getting super messy.

In terms of the bacglock, I've got video somewhere of a tandem having a baglock that slightly tilts them head high but they quickly are returning to tandem terminal, not maintinaing their same speed. All malfunctions are different, larger pilotchutes and drogues may tilt you more head high and have you presenting less surface area to the relative wind and that may have you speeding up, other times the drag may be small enough that it does not alter your body position and you end up still at belly speeds.


peregrinerose  (D 28983)

Nov 19, 2007, 8:32 AM
Post #17 of 73 (3382 views)
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Re: [hackish] Will a bag lock slow you down or increase your speed? [In reply to] Can't Post

From a practical standpoint, does it really matter if your freefall speed increases or decreases somewhat with a baglock? Either way, it's a matter of seconds before impact with the earth if no other action is taken. I would think that it's unlikely that a baglock would take you below cypres firing speeds.

I can say that if I ever have a baglock, I'm not going to be wasting time figuring out if I'm going 110 or 150... I'm getting rid of the fucker! Smile


Premier billvon  (D 16479)
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Nov 19, 2007, 9:00 AM
Post #18 of 73 (3360 views)
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Re: [peregrinerose] Will a bag lock slow you down or increase your speed? [In reply to] Can't Post

> From a practical standpoint, does it really matter if your freefall speed
> increases or decreases somewhat with a baglock?

If it decreases it below about 80mph it can prevent the cypres from firing.

From my experience, sometimes bag locks slow you down, sometimes they speed you up, sometimes they don't do much of anything. I've never seen one slow someone down that significantly though. (<80mph)


airtwardo  (D License)

Nov 19, 2007, 9:41 AM
Post #19 of 73 (3328 views)
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Re: [hackish] Will a bag lock slow you down or increase your speed? [In reply to] Can't Post

As I said in the incidents thread, there are many variables but a bag lock can speed you up...obviously not a scenario discussed by some instructors these days. ShockedCrazyUnimpressed

It's a high speed malfunction regardless, and should be dealt with accordingly.

On the two bag lock malfunctions I've witnessed, one was from the saddle. It was borrowed gear for a demo and though I never bought the software and downloaded the record for eternity, I wrote in my log that I went from 125 in freefall to the high 170's under the 'whistling bag of shit'.

Some of the variables were that I'm a large economy size jumper, small Zpo PC and small bag and some extra weight strapped onto me.

It was enough to stand me up & I 'believe' I was still accelerating when I chopped and could tell I slowed down when I went back to flat & stable prior to unpacking the reserve. (one reason I don't use an RSL)

The 2nd I witnessed at a world convention when a jumper went past me in freefall towing a bag & pilot chute at 3000'.

Granted he didn't go by me real fast...but he was going down faster draggin stuff, than me with nothing out.


winsor  (D 13715)

Nov 19, 2007, 11:20 AM
Post #20 of 73 (3274 views)
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Re: [hackish] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

Can anyone add anything to this discussion?
Sure.

Take care not to spend your time picking flyshit out of pepper.

The point to get out of this is that a bag lock is as bad of a high-speed malfunction as you could hope for. If you think the numbers make a hell of a lot of difference one way or another, you don't get it.


BSBD,

Winsor


kelpdiver  (B 7)

Nov 19, 2007, 1:07 PM
Post #21 of 73 (3231 views)
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Re: [hackish] Will a bag lock slow you down or increase your speed? [In reply to] Can't Post

In reply to:
If the baglock has sufficient drag to stand you up from a stable flat position then it must be applying a fair amount of force to your body. I believe by definition that amount of force sufficient to stand you up would cause you to decelerate, not accelerate even if you were presenting a smaller aerodynamic drag.

It doesn't take much force applied to your shoulder (where the risers attach) to pivot your body into the standing position. Think about that - you can do backflips easily enough.

In a PCIT situation, the drag is applied pretty close to your center mass, so it acts as a slowing force while your drag is likely to remain constant.


NickDG  (D 8904)

Nov 19, 2007, 1:49 PM
Post #22 of 73 (3213 views)
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Re: [kelpdiver] Will a bag lock slow you down or increase your speed? [In reply to] Can't Post

I've see more than a few go in flat and stable with nothing out, and also two go in with stand up baglocks.

To my eyes the baglockers were definitely moving faster . . .

NickD Smile
BASE 194


Premier DSE  (D 29060)
Moderator
Nov 19, 2007, 1:57 PM
Post #23 of 73 (3207 views)
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Re: [NickDG] Will a bag lock slow you down or increase your speed? [In reply to] Can't Post

Logically, it seems that a baglock would increase fall rate, not slow it down. Feet to earth with a small PC would (in my mind) be faster than belly to earth with same PC, no?


Ether

Nov 19, 2007, 2:15 PM
Post #24 of 73 (3194 views)
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Re: [tree102678] Fatality - Skydive Spaceland - Nov 7, 2007 [In reply to] Can't Post

In reply to:
I may be a newbie and all, but I would have to agree with Spence on that one. Drag or no drag.....a Baglock would more than likely stand you up vertical so you would be indeed freefalling faster than the good ol' belly to earth position. Just my 2 cents.

By that logic, your fall rate under a fully deployed and flying canopy should be faster as well, because it also stands you up.

One must also take into consideration the drag induced by the bag, of course.


NickDG  (D 8904)

Nov 19, 2007, 2:29 PM
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Re: [DSE] Will a bag lock slow you down or increase your speed? [In reply to] Can't Post

And I just remembered this one . . .

I had an honest to goodness streamer on a square once. It was an old Glidepath Clipper and it came out of the bag alright and pulled me upright, but I felt myself going past upright and start accelerating.

I reached up and shook and pulled on the risers but the slider, which I couldn't see, was still folded into the bottom of the canopy. And absolutely nothing was happening. This wasn't a snivel it was a real streamer. I couldnít believe it . . .

Anyway, even with the drag of a streamered canopy out, never mind just a small bag, you'll go faster.

I wrote about it for Precision Parachutes when they used to print stories from people who used a Raven reserve to save themselves on their website. It's off the web now, but here's a copy:

NickD Smile
BASE 194

Timebombs . . .

George W. Galloway
Precision Aerodynamics, Inc.
Dunlap, Tennessee USA

Dear George,

Skydiving instructors good at their craft know students must be carefully watched and cleverly handled. They also know students are time bombs. Our morning staff meeting divvies things up and Iím assigned a static line class consisting of two students. I learned my trade jumpmastering static line students and in this accelerated world of student instruction I enjoy teaching and slinging the odd static line class.

Manual is young, capable, and a tad confused. Patrick is quicker of mind but seriously out of shape. Class goes slowly as Manual struggles with the concept of a windsock. There are two types of students. Some are capable of comprehending the whole picture, some just a snapshot. With the latter, priorities are limited to dive flow, how to recognize a good canopy from a bad one, emergency procedures, and how to fly a pattern and land. Everything else is gravy.

I resorted to taking Manual orally through every step over and over like a student pilot goes around and around the pattern until thereís a good chance heíd make it around once without an instructor in the plane. By late afternoon theyíre ready. Sitting against the rear bulkhead of the Twin Otter Patrick looks confident and ready. Manual manages a weak smile. He is operating on pure guts.

No matter which instructor rating you hold, you are paid for just one thing. In AFF its make sure a ripcord gets pulled. In tandem itís make sure the passenger is attached to you. Here, itís making sure the static line is hooked to something else besides the student. Manual is going first on the theory of less distance from the door, less mistakes. I carefully hooked him up and handed him the static line to pull on and double check. Stroking his shoulder I looked deep into his eyes trying to beam him the confidence he needed. He reached out and grabbed the gripper on my jumpsuit leg, even after I told him not to in class, but I let him hang on.

Most jumpmasters donít take advantage of it, but say something to someone sitting in the open door of an aircraft for the first time, and they never forget it. Putting my mouth to his helmet I give some last minute exit advice, told him I was very proud of him, and tapped him out. He pushed forward into the relative wind and hit a nice arch looking up and counting like a champ. He had one line twist that cleared before he knew it. Patrick leaped into the door and did another good exit.

I checked my handles going through the door at 4,500-feet and lay on my back watching the Twin Otter climb away. Passing Patrickís and Manualís canopies I notice they are both heading the right way. Ten seconds gone and just passing 3500-feet Iím working on my inverted reaper roll until I hit two grand and pitched.

Iím thinking how happy and relieved Manual must be as deployment pulls me upright. What? I go over center and start to accelerate looking up at a perfect streamer. Eighteen hundred jumps (and after 12 years of teaching it) here comes my very first cutaway. My Super Raven opens fast, and on-heading. Never seeing my drama Manual and Patrick are down safe and overjoyed, Manual keeps trying to hug me. Iíll tell you something Mr. Galloway; I could never concentrate on my students that much without a Super Raven reserve on my back.

Thank you,

Nick Di Giovanni
D-8904
AFF S/L I
Senior Rigger # XXXXXXXXX


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