Rubber bands

[loch1957 0]

Ok I admit I'm tad confused here, are you supposed to double wrap the lines with rubber bands or not?

Derek's gear tips say "Use the proper size rubber bands, 'Sky Bands', or 'Tube Stows' and do not double wrap them".

However Nick Grillet of Performance Designs double wraps in this video, or is this not double wrapping? http://www.youtube.com/watch?v=qyM_LkW8DVI&feature=relmfu

So why the difference? is there a reason or just preference?

Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure, or nothing.”

[phoenixlpr 0]

Quote

Ok I admit I'm tad confused here, are you supposed to double wrap the lines with rubber bands or not?

Derek's gear tips say "Use the proper size rubber bands, 'Sky Bands', or 'Tube Stows' and do not double wrap them".

However Nick Grillet of Performance Designs double wraps in this video, or is this not double wrapping? http://www.youtube.com/watch?v=qyM_LkW8DVI&feature=relmfu

So why the difference? is there a reason or just preference?

'Sky Bands', or 'Tube Stows' are not plain rubber band, so do do not double wrap them.

Difference of what?

[JohnSherman 1]

Rubberbands need never to be double wrapped, that is if the components of the line stows are ballanced.
The conponents are the "bights" and the "stows".
In size and mass 1 stow should equal 2 bights.
See: http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=NEWSTOW&SortBy=DATE_D
for a graphic depicting a balanced araingment. The article is an old one and has since been updated but the bit about the balanced line stows is fact.
We use the same size standard Mil Spec Rubber band for all applications on our products from Tandem to minies.

The Rubber band doesn't have to be tight to do it's job. By moving the stow inboard to the 25% point the mass of the lines is putting equal stress in both directions during bag extraction preventing line strip or dump. If your stow loops are on the edge of your bag the bight can easily be overcome by the mass of the stows between the bights. Maybe then you might need to double wrap but you will not get 100% results in line retentions. Additionally, We don't reccommentd anything but Mil Spec Rubber bands. They do break for a reason at 40 pounds.

Additional reading:http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Rubberbands&SortBy=DATE_D
http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Speedbag&SortBy=DATE_D
http://www.jumpshack.com/default.asp?CategoryID=TECH&PageID=Reserve_Speedbag&SortBy=DATE_D

[skydiverkeith 1]

I have a Mirage G4. Locking stows are small bands single wrapped. All other stows are large bands double wrapped. If I used small bands and single wrapped I would run the risk of lines shifting while closing the container. Its happened to me before. Do whatever works for your particular gear.

Blue skies,
Keith Medlock

[Skydivesg 6]

Quote

Ok I admit I'm tad confused here, are you supposed to double wrap the lines with rubber bands or not?

Derek's gear tips say "Use the proper size rubber bands, 'Sky Bands', or 'Tube Stows' and do not double wrap them".

However Nick Grillet of Performance Designs double wraps in this video, or is this not double wrapping? http://www.youtube.com/watch?v=qyM_LkW8DVI&feature=relmfu

So why the difference? is there a reason or just preference?

Here is a post I made about one year ago on this same subject in a different thread.

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I can't comment on what is the correct amount of force to deploy single or double wrap stows.

However, I have been double wrapping my stows for more than ten years dating back to when I jumped an original Sabre. So I've used it on Sabres 1 & 2, Stilletto, Samurai, Katana and Velocity.

I use packers on 70-80% of my jumps and always told them to double stow everything including the locking stows. Some times they were reluctant but I always insisted and even monitored those who were shy about doing it.

I've had the advantage of seeing video of many openings specifically shot to show the opening sequence of a deploying canopy. I have seen some very ugly footage.

One of things that is quite noticable is how distorted the bag becomes during the line deployments. The top of the bag is pulled up by the pilot chute often causing the sides to get squeazed in giving the bag a trapazoid look. This dramatically reduces the tension on the line stows of which so many of you speak.

On weather days and safety day I have taken several bags of friends at our dz and emulated this distortion on the ground. It's amazing (and funny) to see the reactions of people when they see their lines just fall out of the stows in no specific order.

And bare in mind, I don't know anyone who replaces all the bands on their bag at the same time. Instead, we replace them as they break or are very near breaking. This means that some of the bands are new and the rest are in various stages of wear with huge differences in force required to deploy the line stow.

Also bare in mind that PD uses their sponsored athletes for feedback on various topics, including this one. So the recommendation is not based on just the R&D department, which for me would be enough, it includes thousands of jumps from the field.

I'm not in R&D for anyone and I'm not a rigger. I'm just some guy making a few hundred jumps a year trying not to have a malfunction and trying to stay healthy enough to make a few thousand more.

I have made several thousand jumps double stowing large bands on all my stows and I plan on making many more.

Be the canopy pilot you want that other guy to be.