Packing Rounds for BASE

[guest]

[font size="1" color="#FF0000"]LAST EDITED ON Aug-28-00 AT 07:20 PM (PST)[/font][p]I'm just starting to experiment with rounds for intentional water jumps. Can anyone out there with more experience help me by answering a couple questions?

1) Why do BASE jumpers generally remove the diaper on a round?

It occurs to me that the diaper might make a slower deployment. However, it is presumably there for a reason (such as preventing inversion). Are there possible negative side effects to removing the diaper?

Are rounds typically jumped with or without the diaper? Does this depend on the delay taken (i.e. is the diaper like a slider in that you put it on for longer delays)?

2) If you are not using a diaper, how do you stow your lines?

I have seen line stows placed at the bottom of the pack tray. Is this the preferred method? Should the lines be stowed inside the risers, or should the risers be placed behind the line stows (i.e. stow over the top of the risers)?

What about using some kind of locking stow at the base of the canopy to better stage the deployment (i.e. keep the canopy together until line stretch)?

3) Are there possible negative side effects to simply free stowing the lines in the bottom of the pack tray?

Is it possible to have a line dump create an inversion (I'm thinking "round line over")?

4) Has anyone used a nose pocket (i.e. tail pocket on the nose of the round used to stow the lines)? How would this work out?

Thanks for helping with anything you can.

--Tom Aiello
tbaiello@ucdavis.edu

[guest]

Tom here are some answers to your questions:


>1) Why do BASE jumpers
>generally remove the diaper on
>a round?

Don't physically remove it, but don't include it in the deployment configuration until you reach higher speeds (5 sec. +)
>
>It occurs to me that the
>diaper might make a slower
>deployment. However, it is
>presumably there for a reason
>(such as preventing inversion).
>Are there possible negative side
>effects to removing the diaper?
>
Lineover/Inversion are posssible side effects of not using a diaper. At the lower speeds it is less likely. However low speeds combined with diapers have a more severe potential side effect-impact.
>
>Are rounds typically jumped with or
>without the diaper? Does
>this depend on the delay
>taken (i.e. is the diaper
>like a slider in that
>you put it on for
>longer delays)?

For shorter BASE delays rounds are usually deployed without the diaper and the apex of the canopy rubber banded. Rubber banding the apex artificially alters the canopy's shape and encourages a faster opening.
>

>2) If you are not
>using a diaper, how do
>you stow your lines?

In the pack tray (with stows)


>I have seen line stows placed
>at the bottom of the
>pack tray. Is this
>the preferred method? Should
>the lines be stowed inside
>the risers, or should the
>risers be placed behind the
>line stows (i.e. stow over
>the top of the risers)?

I prefer the idea of risers on bottom as they will come out last. On the Perigee/Tektite rig they sit under but slightly to the outside of the stowed lines.
>
>
>What about using some kind of
>locking stow at the base
>of the canopy to better
>stage the deployment (i.e. keep
>the canopy together until line
>stretch)?

Low snatch forces at this stage of deployment could lead to hesitation. When a round reaches the end of it's lines it begins to inflate top down. Low pressure surounding the upper part of the canopy starts this process. This is different from the mechanicaly induced latereral forces generated by the lower surface presurization of a ram air.


>3) Are there possible negative
>side effects to simply free
>stowing the lines in the
>bottom of the pack tray?

Entanglements.

>
>Is it possible to have a
>line dump create an inversion
>(I'm thinking "round line over")?

Packing or grossly unstable deployment are the largest causes of lineovers. Round parachutes have lines of equal lengths so something like line dump (or poor deployment sequencing)is less of a factor than w/ a ram air. The key is to have the skirt both level and evenly loaded during and at at line stretch.

>4) Has anyone used a
>nose pocket (i.e. tail pocket
>on the nose of the
>round used to stow the
>lines)? How would this
>work out?

I don't know. I would be concerned about it's mass encouraging an inversion during deployment.


Have fun

Adam Filippino
http://www.crmojo.com

[346]

I've jumped a round with a nose pocket on everything from a go-and-throw up to a 4 second delay.

I removed the diaper simply because I knew I wouldn't be jumping that canopy on anything longer than that. If I were to jump the round on longer delays, I would definitely be considering using a diaper and 45'ing the skirt.

The nose pocket I installed was in the same place where the diaper used to be - that is, on the radial seam, rather than in the center of the gore. I don't 45 the skirt. I simply fold the canopy in thirds at skirt (to match the width of the container) and keep that width as I go up the canopy (which lasts about 2/3rds of the way to the apex). Deployments have always been very clean and on heading.

This is a 22-ft SAC after about a 2-second delay:

http://base346.tripod.com/base/basegal1/mjmp013.jpg

[guest]

Besides the answers/advice you get here, you might try to lookup Rich Stein - he has a ton of round jumps. . .