Forums: Skydiving: Gear and Rigging:
do any other manufacturers or engineers support the speedbag?

 

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darnknit  (D 12852)

May 1, 2006, 2:25 PM
Post #1 of 94 (2346 views)
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do any other manufacturers or engineers support the speedbag? Can't Post

in a different thread in this forum, a post was made claiming that gear manufacturers besides Jumpshack supported the speedbag design. when asked which manufacurers support the design the answer was, "an engineer at RWS".

i would like to here from people involved with manufacturing sport skydiving gear (outside of Jumpshack) what they think of the speedbag.

my motive here is to learn. if a design can be praised openly by the competition, then it must truly be a good design.

blue stuff,
p.j.


mjosparky  (D 5476)

May 1, 2006, 4:16 PM
Post #2 of 94 (2260 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Good luck on getting a straight answer on that one.Unsure


Slurp56

May 1, 2006, 4:53 PM
Post #3 of 94 (2241 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

In reply to:
if a design can be praised openly by the competition, then it must truly be a good design.

blue stuff,
p.j.

How much of the competition praises the skyhook?


darnknit  (D 12852)

May 1, 2006, 5:13 PM
Post #4 of 94 (2223 views)
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Re: [Slurp56] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Quote:
How much of the competition praises the skyhook?

i don't know, but i am not aware that anyone has said that other manufacturers support the skyhook.

i am aware that someone has said other manufacturers support the speedbag. i am trying to find out if this is true, and if it is, i would like to know why other manufacturers think it is a good idea. i am just trying to learn.


rigger_john  (C 101098)

May 2, 2006, 1:06 AM
Post #5 of 94 (2120 views)
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Re: [Slurp56] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

In reply to:
How much of the competition praises the skyhook?

Derek Thomas told me he wanted to put the skyhook on the Javelin! I guess that could count as praise.


RMURRAY

May 2, 2006, 2:57 AM
Post #6 of 94 (2094 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

In reply to:
in a different thread in this forum, a post was made claiming that gear manufacturers besides Jumpshack supported the speedbag design. when asked which manufacurers support the design the answer was, "an engineer at RWS".

i would like to here from people involved with manufacturing sport skydiving gear (outside of Jumpshack) what they think of the speedbag.

my motive here is to learn. if a design can be praised openly by the competition, then it must truly be a good design.

blue stuff,
p.j.

I'd say watch what their actions are in the future. I think they will all come out with something similar - because there is a (potential) problem that needs addressing. Which manufacturers have moved away from the safety stow already?

rm


Premier PhreeZone  (D License)
Moderator
May 2, 2006, 6:11 AM
Post #7 of 94 (2050 views)
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Re: [RMURRAY] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Jumpshack is the only one that I've seen that has moved their reserves bags away from the free stow. The speed bag has been out for a few years now, if it was the next hot thing you'd be hearing everyone asking when will it be availble on X rig lke the Skyhook. As it stands now its a one off design that is still an unknown in the market place.


BillLockwood  (D License)

May 2, 2006, 6:58 AM
Post #8 of 94 (2023 views)
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Re: [PhreeZone] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Quote:
As it stands now its a one off design that is still an unknown in the market place.
Using that analogy you could say the same thing about the skyhook. Also, by definition and the fact that it is a production item that is made in different sizes for both sport and tandem it is not a one off design.
Quote:
Jumpshack is the only one that I've seen that has moved their reserves bags away from the free stow.
Does the Icon use free stow or another design?


(This post was edited by BillLockwood on May 2, 2006, 7:00 AM)


riggerrob  (D 14840)

May 2, 2006, 8:08 AM
Post #9 of 94 (1998 views)
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Re: [BillLockwood] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

quote]Does the Icon use free stow or another design?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Icon uses a free-floating safety-stow, like the next hundred manufacturers.


riggerrob  (D 14840)

May 2, 2006, 8:13 AM
Post #10 of 94 (1991 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Does my opinion count?
Over the years, I have worked for three major manufacturers: Butler Parachute Systems, Rigging Innovations and Para-Phernalia.

Safety-stows are optimized for the low speed edge of the envelope, while speed-bags are optimized for the high speed edge of the envelope, but both function properly over the entire envelope.

Both work!
What is the fuss?


Premier PhreeZone  (D License)
Moderator
May 2, 2006, 8:17 AM
Post #11 of 94 (1988 views)
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Re: [BillLockwood] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

The Icon uses a Safety Stow. Here is the manual showing it: http://www.aerodyne-int.com/...load/icon_manual.pdf


darnknit  (D 12852)

May 2, 2006, 8:32 AM
Post #12 of 94 (1977 views)
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Re: [riggerrob] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Quote:
Both work!
What is the fuss?

there is no fuss, i'm just asking a question in an effort to learn more.


BillLockwood  (D License)

May 2, 2006, 8:59 AM
Post #13 of 94 (1962 views)
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Re: [PhreeZone] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

 
Quote:
Jumpshack is the only one that I've seen that has moved their reserves bags away from the free stow.
I was talking about the free stow part of your post. I think that the Icon uses flutes to stow the lines instead of free stowing. I looked at the manual that you posted but it does not show putting the canopy in the bag or stowing the lines.


justinb138  (B 28762)

May 2, 2006, 9:13 AM
Post #14 of 94 (1948 views)
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Re: [BillLockwood] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

In reply to:
Quote:
Jumpshack is the only one that I've seen that has moved their reserves bags away from the free stow.
I was talking about the free stow part of your post. I think that the Icon uses flutes to stow the lines instead of free stowing. I looked at the manual that you posted but it does not show putting the canopy in the bag or stowing the lines.

The ICON uses has elastic stow bands in the velcro pouch on the freebag to stow the lines.

For some reason, I don't remember it being mentioned in the packing manual though.Crazy


darnknit  (D 12852)

May 2, 2006, 10:43 AM
Post #15 of 94 (1906 views)
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Re: [RMURRAY] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Quote:
I think they will all come out with something similar - because there is a (potential) problem that needs addressing

what (potential) problem needs to be addressed?

Quote:
Which manufacturers have moved away from the safety stow already?

the only TSO'd freebag design that i am aware of in current use(excluding the speedbag) that does not use a safety stow is the strong dualhawk with a master 425 reserve. that particular design predates the speedbag.


RMURRAY

May 2, 2006, 4:26 PM
Post #16 of 94 (1834 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

In reply to:
what (potential) problem needs to be addressed?

from the jumpshack site in case you haven't read...

In January of 2003, at the PIA Symposium in Jacksonville, Florida, John Sherman introduced the Speedbag as a solution to the possibility of line dump during a reserve deployment.

Most freebags produced in the U.S. utilize a single, looped, piece of shock cord bungee to create two locking stows, with the balance of the lines S folded into a pouch that is held closed by two pieces of Velcro with a single exit point in the center.

One downside of this system is that there is no rigidity between the locking stows. No matter how carefully a rigger packs, the stow will always create uneven tension on the line bights, allowing the possibility of line dump. Also should the locking stow break (and it only needs one break to release both stows) the lines can dump out and the canopy can inflate before line extension creating the possibility of catastrophic failure.

With more people loading their reserves heavily and flying their bodies at greater speeds the potential for this situation is greatly enhanced.

Sherman devised a bag, where every stow is a locking stow, and the lines are held in place by rubber bands (bands conforming to mil. Spec. R-1832 are recommended). Furthermore the stows are placed on the bag so that the mass of the lines is evenly balanced, offering a greater opportunity for even deployment. When stowed correctly, 50% of the mass of each line stow is between each pair of stows with 25% of the mass on the left outside and 25% on the right outside.

Quite simply the speedbag has two closing flaps that overlap. The first flap to cover the canopy has two rows of rubber bands while the second, overlapping, flap has soft grommets sewn into it. The rubber bands secure the lines in a balanced and orderly fashion, and should any band break during the deployment sequence, the lines cannot dump out as the next stow in sequence regains control of the deployment.

The absence of metal grommets avoids the possibility of any reaction with, or abrasion against, the rubber, and the ordered and controlled line deployment offers the potential for a safer reserve deployment.

The Speedbag was throughly tested as both a main and a reserve deployment bag and, while the main bag is an available option, the reserve version is now supplied as standard with all Racer models.


TimDave  (D 25554)

May 2, 2006, 5:23 PM
Post #17 of 94 (1816 views)
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Re: [RMURRAY] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

There are military designs out there that use flutes in addition to single free stow designs.


darnknit  (D 12852)

May 2, 2006, 5:30 PM
Post #18 of 94 (1812 views)
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Re: [RMURRAY] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

 

so, are there any incidents where a safety stow freebag experienced line dump, or bag strip?

or is bag strip, and line dump only a potential problem with a safety stow freebag?


RMURRAY

May 3, 2006, 2:59 AM
Post #19 of 94 (1751 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

In reply to:

so, are there any incidents where a safety stow freebag experienced line dump, or bag strip?

or is bag strip, and line dump only a potential problem with a safety stow freebag?

this has been all talked about before. search the forums using "nancyj" (nancy from jumpshack) and read what she has had to say. I think what she is saying very carefully is that the root cause of the Raven line attachment issue was not the fault of the reserve - it was the fault of the reserve deployment system.....

"I forgot to mention the other deficiency of the old style bungee stow/pouch freebag - the destruction of reserve canopies in the event of line strip. There've been several instances where lines tore from reserve canopies, or canopies blew up as a result of line strip. It's not that the canopies were not built strong enough - it's that the deployment system did not meter the lines out in a controlled manner, and sufficiently soften the opening. There has been more than one fatality as a result."


darnknit  (D 12852)

May 3, 2006, 4:56 AM
Post #20 of 94 (1732 views)
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Re: [RMURRAY] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Quote:
I think what she is saying very carefully is that the root cause of the Raven line attachment issue was not the fault of the reserve - it was the fault of the reserve deployment system

if i recall correctly, precisions opinion was that the user had overloaded his reserve. was anyone from jumpshack involved in the investigation?

Quote:
There've been several instances where lines tore from reserve canopies, or canopies blew up as a result of line strip.

can you be more specific? i asked this question a month or so ago, i didn't get any responses citing a specific incident.


riggerrob  (D 14840)

May 3, 2006, 6:59 AM
Post #21 of 94 (1698 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Jump Shack was NOT involved in the torn Raven - circa 2001 - at Perris Valley, California. That Raven 282-M was packed into a Reflex container.
Since the guy was over-weight, over-speed and unstable when he scared his Cypres, no one tried to blame the container manufacturer (Fliteline).
Since he was over-weight, over-speed and unstable when he scared his Cypres, few riggers were willing to blame the canopy manufacturer (Precision) either.

None of us even considered the possibility of line dump or bag strip.


riggerrob  (D 14840)

May 3, 2006, 7:05 AM
Post #22 of 94 (1693 views)
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Re: [darnknit] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

On the subject of "flutes" (small cloth tubes) for line stows, Manley Butler explained that rubber bands don't work above 250 knots, that is why many ejection seats use cotton flutes for line stows.
Since few civilians deploy that fast, flutes are rare in civilian skydiving gear.
The first time I saw flutes in a skydiving rig was in an Atom, built by Parachutes de France.
I think (?) Aerodyne's Icon also has flutes.
The Aviator PEP - from Rigging Innovations - has light elastic flutes, but that is more for bulk distribution and pilot comfort. Every one else just figure-eights lines loosely in a line stow pocket. The better line stow pockets (Genera, Sidewinder, Talon 2, Telesis 2, Voodoo, Wings, etc.) are closed by Velcro in shear, almost preventing line dump.


davelepka  (D 21448)

May 3, 2006, 7:12 AM
Post #23 of 94 (1685 views)
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Re: [riggerrob] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Quote:
Jump Shack was NOT involved in the torn Raven - circa 2001 - at Perris Valley, California. That Raven 282-M was packed into a Reflex container

In all fairness, Jump Shack never claimed to be involved. However, a safety stow type freebag was invloved, which is what they are attempting to address with the speed bag.

That aside, the speedbag seems like an awful lot of locking stows between my reserve and the freedom it deserves. I wonder if theres a middle-ground solution, like maybe four locking stows, with the reat in a pouch, or even just conventional stows.

Just to be clear, I don't mean four locking stows as you see on many main D-bags, where the locking stows often end up on top of one another. I 'm talking about two parallel rows of two locking stows each.


riggerrob  (D 14840)

May 3, 2006, 8:49 AM
Post #24 of 94 (1651 views)
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Re: [riggerrob] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

Reply to TSOD chris,

Since the victim made so many mistakes - on his way to the scene of the accident - we did not seriously consider the possibility of line dump/bag strip.
Any one of the afore-mentioned (over-weight, over-speed, unstable, while scaring his Cypres, etc.) factors might have torn the reserve. All those factors are clearly understood.
Most aircraft wrecks are found at the end of a chain of mistakes.


RMURRAY

May 3, 2006, 9:25 AM
Post #25 of 94 (1630 views)
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Re: [riggerrob] do any other manufacturers or engineers support the speedbag? [In reply to] Can't Post

In reply to:
Reply to TSOD chris,

Since the victim made so many mistakes - on his way to the scene of the accident - we did not seriously consider the possibility of line dump/bag strip.
Any one of the afore-mentioned (over-weight, over-speed, unstable, while scaring his Cypres, etc.) factors might have torn the reserve. All those factors are clearly understood.
Most aircraft wrecks are found at the end of a chain of mistakes.

is line dump / bag strip a possible root cause for this accident?

rm


(This post was edited by RMURRAY on May 3, 2006, 9:26 AM)


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