Forums: Skydiving: Safety and Training:
Freebag Lockup

 


Squeak  (E 1313)

Dec 12, 2012, 1:18 AM
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Freebag Lockup Can't Post

Anyone know the story behind this?
John Sherman?


JohnSherman  (D 2105)

Dec 12, 2012, 1:25 AM
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Re: [Squeak] Freebag Lockup [In reply to] Can't Post

Quote:
Anyone know the story behind this?
John Sherman?

Yes, I do. What would you like to know?


piisfish

Dec 12, 2012, 1:27 AM
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Re: [Squeak] Freebag Lockup [In reply to] Can't Post

ShockedShocked


Squeak  (E 1313)

Dec 12, 2012, 1:41 AM
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

In reply to:
Quote:
Anyone know the story behind this?
John Sherman?

Yes, I do. What would you like to know?
Like the OP states, what's the story behind it?


wolfriverjoe  (A 50013)

Dec 12, 2012, 6:44 AM
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

In reply to:
Quote:
Anyone know the story behind this?
John Sherman?

Yes, I do. What would you like to know?

Well, it says "Main 170sq ft." What size reserve? What size container (IOW, what size main and reserve were supposed to be in there)?


airtwardo  (D License)

Dec 12, 2012, 8:40 AM
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Re: [Squeak] Freebag Lockup [In reply to] Can't Post

Ad for crazy glue? Wink


Premier skydiverek  (C 41769)

Dec 12, 2012, 9:06 AM
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Re: [airtwardo] Freebag Lockup [In reply to] Can't Post

From JumpShack FB page:

"Parachute Labs, Inc.: This was not staged. It was just a customer rig that came in for inspection & repack. Boxing of the upper portion of the reserve container, tuck tabs and riser covers encroaching over the side flaps all contributed to holding the reserve d-bag in."


JohnSherman  (D 2105)

Dec 12, 2012, 11:01 AM
Post #8 of 44 (4285 views)
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Re: [wolfriverjoe] Freebag Lockup [In reply to] Can't Post

Quote:
Well, it says "Main 170sq ft." What size reserve? What size container (IOW, what size main and reserve were supposed to be in there)?

It was a V3 with a PD176R packed on 3/20/2001 and as said a 170 main. It was not staged. Remember the fact that the main was full and packed, this might make a difference.
I don't know what is supposed to go in there as it came to us packed for cyclic inspection and we videoed it as we often routinly did. I believe the combinations were correct. This happened in 2001 and has been on the web for that long. It is not uncommon. Yes the owner was told and shown the video. I don't believe he is in the sport any longer.
A USPA Bullitin issued a couple of years ago solicited info about situations like this to be reported to the PIA tech comm.
There has been considerable conversation over the years on this forum. If you want to know about more, just ask for it. I am sure you will get your inbox filled.


popsjumper  (D 999999999)

Dec 12, 2012, 11:34 AM
Post #9 of 44 (4251 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

We've seen this one before quite a while back IIRCC

Well John, I noticed that the direction of pull was not as it would have been in the air...unless the jumper was standing upright at reserve deployment.

Rigs are not designed to have the bag come out at that angle.


Deyan  (D 322)

Dec 12, 2012, 11:53 AM
Post #10 of 44 (4223 views)
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Re: [popsjumper] Freebag Lockup [In reply to] Can't Post

In reply to:
Well John, I noticed that the direction of pull was not as it would have been in the air...unless the jumper was standing upright at reserve deployment.

Rigs are not designed to have the bag come out at that angle.

Question for you...

Total malfunction...the jumper freaks out because he can't find his reserve handle. He stops arching and he goes butt down.....the AAD fires.

Which direction the RPC will go and what will be the angle of pulling ?


JohnSherman  (D 2105)

Dec 12, 2012, 12:17 PM
Post #11 of 44 (4195 views)
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Re: [popsjumper] Freebag Lockup [In reply to] Can't Post

Quote:
Well John, I noticed that the direction of pull was not as it would have been in the air...unless the jumper was standing upright at reserve deployment.

Usually, when I have a partial, the malfunctioned main sets me up into the vertical. I know that it would be wrong for me to go back into the horizontal because I want the air flowing over my back to sweep off any possibility of a burble. Additionally, I am in a position to accept opening shock. Likewise when I am deploying from the horizontal (main or reserve) I "Sit up and dump" or get vertical for the above reasons. The biggest problem I have with test jumpers is that they want to go back to the horizontal after release. Thats dead wrong, fly on you shins, stay vertical. You will get a faster smoother opening.

Quote:
Rigs are not designed to have the bag come out at that angle.
Oh!

I have been designing rigs for 40 years and didn't know that.


Quagmirian  (A 110392)

Dec 12, 2012, 1:00 PM
Post #12 of 44 (4152 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

I was under the impression that a hard arch is the worst possible position for a reserve deployment.


airtwardo  (D License)

Dec 12, 2012, 1:20 PM
Post #13 of 44 (4137 views)
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Re: [Quagmirian] Freebag Lockup [In reply to] Can't Post

In reply to:
I was under the impression that a hard arch is the worst possible position for a reserve deployment.

?? Please explain.

I have 14 reserve rides and hard arched then manually deployed each one...what am I dong wrong?


Premier Remster  (C License)

Dec 12, 2012, 1:41 PM
Post #14 of 44 (4111 views)
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Re: [airtwardo] Freebag Lockup [In reply to] Can't Post

Quote:
I have 14 reserve rides and <...>...what am I dong wrong?

Packing comes to mind... TongueWink


Deyan  (D 322)

Dec 12, 2012, 1:48 PM
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Re: [Remster] Freebag Lockup [In reply to] Can't Post

In reply to:
Quote:
I have 14 reserve rides and <...>...what am I dong wrong?

Packing comes to mind... TongueWink

LaughLaughLaugh


Premier skydiverek  (C 41769)

Dec 12, 2012, 2:19 PM
Post #16 of 44 (4068 views)
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Re: [popsjumper] Freebag Lockup [In reply to] Can't Post

In reply to:
Well John, I noticed that the direction of pull was not as it would have been in the air...unless the jumper was standing upright at reserve deployment.

Rigs are not designed to have the bag come out at that angle.

How about an RSL reserve deployment, after a bag-lock cutaway (which stood you up)?


stratostar  (Student)

Dec 12, 2012, 2:56 PM
Post #17 of 44 (4032 views)
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Re: [Remster] Freebag Lockup [In reply to] Can't Post

Quote:
Packing comes to mind...

Ya can't teach "some" grumpy crotchety old fucks new tricks....Laugh


stratostar  (Student)

Dec 12, 2012, 2:57 PM
Post #18 of 44 (4025 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

Quote:
Oh!

I have been designing rigs for 40 years and didn't know that.

Oh well now we all know why you've been doing things wrong all this time..... LOLLaugh

JK.Tongue


JohnSherman  (D 2105)

Dec 12, 2012, 3:05 PM
Post #19 of 44 (4013 views)
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Re: [stratostar] Freebag Lockup [In reply to] Can't Post

Quote:
Oh well now we all know why you've been doing things wrong all this time..... LOL

Yeah, now I have to go and modify all thoes Racers so they will hold the bag in at that angle. I'll never learn.

Oh BTW: Here is another one:http://www.youtube.com/watch?v=QtgneR9Ei00


diablopilot  (D License)

Dec 12, 2012, 3:59 PM
Post #20 of 44 (3977 views)
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Re: [popsjumper] Freebag Lockup [In reply to] Can't Post

In reply to:
We've seen this one before quite a while back IIRCC

Well John, I noticed that the direction of pull was not as it would have been in the air...unless the jumper was standing upright at reserve deployment.

Rigs are not designed to have the bag come out at that angle.

Not true. They need to be designed for just such a deployment. What is the jumper's orientation in relation to the relative wind the moment post breakaway from a spinning malfunction back to earth when an RSL pulls the pin?

It's exactly that orientation.


airtwardo  (D License)

Dec 12, 2012, 4:51 PM
Post #21 of 44 (3943 views)
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Re: [Remster] Freebag Lockup [In reply to] Can't Post

In reply to:
Quote:
I have 14 reserve rides and <...>...what am I dong wrong?

Packing comes to mind... TongueWink

YOU ever tried to pack a Thunderbow hungover? Angelic


popsjumper  (D 999999999)

Dec 12, 2012, 7:04 PM
Post #22 of 44 (3879 views)
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Re: [Deyan] Freebag Lockup [In reply to] Can't Post

same direction as the relative wind.


(This post was edited by popsjumper on Dec 12, 2012, 7:27 PM)


popsjumper  (D 999999999)

Dec 12, 2012, 7:18 PM
Post #23 of 44 (3866 views)
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Re: [skydiverek] Freebag Lockup [In reply to] Can't Post

In reply to:
How about an RSL reserve deployment, after a bag-lock cutaway (which stood you up)?
What about it? Do you assume that any one body position is going guaranteed operation or non-operation?

Just FYI... a bag lock does not stand you up as a matter of course. It may or may not. So what's your point?

That freebag can come out in just about any body position....or it can stay locked in...as has happened before.


popsjumper  (D 999999999)

Dec 12, 2012, 7:19 PM
Post #24 of 44 (3864 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

OK...your arrogance is showing now. But...it's always nice to know that there is at least one perfect person out there who could never be wrong about anything.

Read the PM.


(This post was edited by popsjumper on Dec 12, 2012, 7:25 PM)


popsjumper  (D 999999999)

Dec 12, 2012, 7:22 PM
Post #25 of 44 (3862 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

In reply to:
Usually, when I have a partial,...
Great. So let's have a discussion about partials instead of stuck freebags.


Andy9o8  (D License)

Dec 12, 2012, 8:02 PM
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Re: [popsjumper] Freebag Lockup [In reply to] Can't Post

In reply to:
OK...your arrogance is showing now. But...it's always nice to know that there is at least one perfect person out there who could never be wrong about anything.

Read the PM.

Unimpressed

http://thelayabout.org/...fighting-206x300.jpg


Premier skydiverek  (C 41769)

Dec 13, 2012, 4:44 AM
Post #27 of 44 (1683 views)
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Re: [popsjumper] Freebag Lockup [In reply to] Can't Post

In reply to:
Just FYI... a bag lock does not stand you up as a matter of course. It may or may not. So what's your point?

That freebag can come out in just about any body position....or it can stay locked in...as has happened before.

Yes, the baglock may, or may not, stand you up. The freebag should come out easily in both orientations.


JohnSherman  (D 2105)

Dec 13, 2012, 10:42 AM
Post #28 of 44 (1580 views)
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Re: [skydiverek] Freebag Lockup [In reply to] Can't Post

Quote:
Yes, the baglock may, or may not, stand you up. The freebag should come out easily in both orientations.

Correct, it actually depends on the capability of your pilot chute. A good pilot chute will stand you up, right now. Free bag hang up is not really the issue here. It is whether or not the reserve pilot chute has the necessary drag to extract the bag. Some manufacturers use pack compression as a staging method (We don't). Pack compression can lead to high extraction forces as we have seen. Does the pilot chute have the capability to overcome those forces? Ask you manufacturer; make him give you numbers and test results. Make him give you a max extraction force so your rigger can make sure the bag will come out within the capability of the pilot chute. Look for Effective Sq. Ft. marked on the pilot chute. You can take that number times the Dynamic pressure for that speed and altitude ( See:http://www.jumpshack.com/Q.htm ) and calculate to and find the drag.

And for god sake if all you have to compare equipment on is comfort, looks, and options dont admit it by declaration. There are too many functional issues which could be asked about.


airtwardo  (D License)

Dec 13, 2012, 11:27 AM
Post #29 of 44 (1559 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

And for god sake if all you have to compare equipment on is comfort, looks, and options dont admit it by declaration. There are too many functional issues which could be asked about.

In reply to:

But but but...if it LOOKS good & it FEELS good it MUST be good!


Maybe if people looked a bit deeper into things the divorce rate wouldn't be so high! Wink


piisfish

Dec 13, 2012, 2:21 PM
Post #30 of 44 (1501 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

Just to corroborate John's affirmation about PC standing you up in a bag lock configuration, I was stood up with mine


Premier skydiverek  (C 41769)

Dec 13, 2012, 2:50 PM
Post #31 of 44 (1490 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

In reply to:
Oh BTW: Here is another one:http://www.youtube.com/watch?v=QtgneR9Ei00

And this one:
http://www.youtube.com/watch?v=vaYQ6iP8zlg


jerolim  (F License)

Dec 14, 2012, 2:20 AM
Post #32 of 44 (1412 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

This is all great. But what I don't like in Racers is the fact - quick loop forms a big eye (compared to normal cypres closing loop). And in freebag there is not tunnel of fabric, only 2 vertical tabs. And this big quick loop eye can teoreticaly catch some reserve fabric (or even vertical tab fabric) and cause freebag lock !

Reflexes also used quick loops, but they have tunnels of fabric in freebags.


pchapman  (D 1014)

Dec 14, 2012, 5:46 AM
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Re: [jerolim] Freebag Lockup [In reply to] Can't Post

The Reflex actually uses a molar freebag I believe. So no tunnel (like is nicely done on an Icon) needed.

But yes one wonders a bit about that design aspect of the Racer, even if it seems to work OK in practice. The loops get pulled through under tension and ideally remain in tension during the pack job (but I'm not sure that always happens in practice). The manual does say the buffer strips are supposed to provide protection, but I'm not sure that that happens on every pack job in practice.

(And the manual still shows what seems like a 1960s military practice, as an option, to do a whole bunch of tacking through the loop. Yikes.)


fcajump  (D 15598)

Dec 14, 2012, 11:43 AM
Post #34 of 44 (1300 views)
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Re: [piisfish] Freebag Lockup [In reply to] Can't Post

In reply to:
Just to corroborate John's affirmation about PC standing you up in a bag lock configuration, I was stood up with mine

My most recent (2008) unplanned cutaway was from a 90% main (brakeline trapped at the attachpoint of a centercell 'C'... long story) spin increasing/backward as the slider dropped.

So I was very verticle to the relative wind at release.

No RSL, Vector II w/ Fury 220. No discernable delay to the deployment, total loss (per altitrack) from release to normalized decent rate under reserve was right at 500'. (chop at ~1800')

Glad to have a comfortable sized reserve and quick deployment. Wife, friends and audience were glad all went smooth.

JW

PS - my only problem with my new Racer is the deployment force (ripcord). Was VERY high when first delivered from the factory. Better the second time from the factory, and my own packjobs are getting better, though still higher than I like. It also seems that, like the Reflex, it would be VERY easy for a field adjustment of the PC tension leading to a hard-pull that gets blamed on the last rigger of record. I bought it to get comfortable with the rig and its differences having never asked to service anyone elses, but I'm not at the point I would take on someone elses yet.


(This post was edited by fcajump on Dec 14, 2012, 11:50 AM)


JohnSherman  (D 2105)

Dec 14, 2012, 8:10 PM
Post #35 of 44 (1222 views)
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Re: [jerolim] Freebag Lockup [In reply to] Can't Post

Quote:
And this big quick loop eye can teoreticaly catch some reserve fabric (or even vertical tab fabric) and cause freebag lock

The British brought that up some 40 years ago. We tried to fail it with a packing paddle trying to push fabric into the tightened loop. No way. We could not make it happen.
Pure speculation can only be absolved by having over 40,000 rig in the field over some 40 years and never have it to happen. The test of time would have failed it if it were to fail.


manseman  (D License)

Dec 17, 2012, 6:51 AM
Post #36 of 44 (1103 views)
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Re: [Quagmirian] Freebag Lockup [In reply to] Can't Post

In reply to:
I was under the impression that a hard arch is the worst possible position for a reserve deployment.
Would you rather deploy on your back then?


JohnSherman  (D 2105)

Dec 17, 2012, 11:51 PM
Post #37 of 44 (1028 views)
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Re: [manseman] Freebag Lockup [In reply to] Can't Post

Quote:
I was under the impression that a hard arch is the worst possible position for a reserve deployment.

It probably is: The biggest impediment to a clean fast opening is burble of the pilot cute. If you are in a stable hard arch you have a big burble on your back. This can cause your poilot chute to dance around looking for the free stream.
The old saying was "Sit up and dump". The lesson was to transition from belly-to-earth to slightly vertical, enought o get the air flowing up over you back. This transition must be made with the shoulders parallel to the ground. If you drop a shoulder you will spin the bag and get line twists.
Keep your shoulders level to keep the lines at even tension. This rotation will sit you into your saddle at just the right time.
To accomplish this I look straight up over my head as to check my canopy which is exactly what I am doing, checking my pilot chute canopy.


Premier skydiverek  (C 41769)

Dec 21, 2012, 5:33 AM
Post #38 of 44 (911 views)
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Re: [skydiverek] Freebag Lockup [In reply to] Can't Post

In reply to:
From JumpShack FB page:

"Parachute Labs, Inc.: This was not staged. It was just a customer rig that came in for inspection & repack. Boxing of the upper portion of the reserve container, tuck tabs and riser covers encroaching over the side flaps all contributed to holding the reserve d-bag in."

I wonder how the attached TearDrop and Zerox would handle this test...


(This post was edited by skydiverek on Dec 21, 2012, 5:48 AM)
Attachments: Tear_Drop_Superf_4b2601c0b86a5.jpg (28.4 KB)
  Zerox_4b26030d051ac.jpg (24.1 KB)


popsjumper  (D 999999999)

Dec 21, 2012, 8:52 AM
Post #39 of 44 (873 views)
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Re: [skydiverek] Freebag Lockup [In reply to] Can't Post

In reply to:
In reply to:
From JumpShack FB page:

"Parachute Labs, Inc.: This was not staged. It was just a customer rig that came in for inspection & repack. Boxing of the upper portion of the reserve container, tuck tabs and riser covers encroaching over the side flaps all contributed to holding the reserve d-bag in."

I wonder how the attached TearDrop and Zerox would handle this test...

Would THAT be a design issue?


riggerrob  (D 14840)

Dec 23, 2012, 11:07 PM
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Re: [jerolim] Freebag Lockup [In reply to] Can't Post

Maybe 15 years ago, John Sherman gave me verbal permission to sew the (Type 12 webbing) tabs together, to better prevent interference between the loop and canopy fabric. I sewed a few together, but quit after I moved back to Canada, since CSPA's old Technical Committee had a rigid attitude towards non-documented modifications.

On a related note, I have only patched a handful of reserves, but most of them were damaged by riggers who used "far more muscle than skill" to pull the closing up loop through the deployment bag.
Those clumsy souls also tried to drag some reserve canopy fabric ...
I have never had to patch a reserve canopy packed into a Racer.

That is why I never liked second-generation freebags (where the closing loop can rub on canopy fabric).
The other reason I like molar bags is that some of them (e.g. Dolphin and Javelin) help create the "crater" needed to deep-seat the exposed pilot-chute.
Not all molar-bags help create that "crater." For example, Reflexes and Wings require more special tricks - than Racers - to deep-seat the pilot-chute.

If John Sherman published a letter allowing me to sew (Type 12 webbing) tabs together, I would resume the practice, however, I believe that the long-term solution is a "shaped" molar bag similar to Javelin.


JohnSherman  (D 2105)

Dec 24, 2012, 8:43 AM
Post #41 of 44 (714 views)
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Re: [riggerrob] Freebag Lockup [In reply to] Can't Post

Rob,

If you want a letter I will give you one. However, I have found no advantage to sewing the edges of the tabs together to form a channel.
As to the "Molar Bag". I have tried numerous times to build one that works. Additionally, every rigger who has ever worked for me has suggested it. I gave each one, in turn, permission and will tell you the same as I told them. "Bring me one that works better than the current design and I will change to it". To date we are still using the original design.

John


JohnMitchell  (D 6462)

Dec 24, 2012, 8:54 AM
Post #42 of 44 (706 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

In reply to:
Quote:
I was under the impression that a hard arch is the worst possible position for a reserve deployment.
Probably better than tumbling randomly, which is what I see on a lot of cutaways. Crazy


In reply to:

The old saying was "Sit up and dump". The lesson was to transition from belly-to-earth to slightly vertical, enought o get the air flowing up over you back.
I teach "feet on butt, pull and arch with hands high". This will put you in a head-high back sliding mode and should have lots of clean air flowing over the back. It's worked pretty well so far.


Deyan  (D 322)

Dec 24, 2012, 10:05 AM
Post #43 of 44 (685 views)
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Re: [JohnSherman] Freebag Lockup [In reply to] Can't Post

In reply to:
However, I have found no advantage to sewing the edges of the tabs together to form a channel.
John

John,

What if you sew the tabs to the top of the freebag around the grommet?
Any cons about that?


JohnSherman  (D 2105)

Dec 25, 2012, 12:17 PM
Post #44 of 44 (601 views)
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Re: [Deyan] Freebag Lockup [In reply to] Can't Post

No Cons, but not necessary, we found no advantage.
We did experiment with it as well as the other ideas.
We have built that Free bag so many different ways including a horse shoe shaped compartment encompasing the grommets and attached to the top and bottom.



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