The Tail-Bury wrap around method or “Tilley Fold”
Introduction
The "TB-pack" is an improvement of the classic base PRO-pack method. It has been developed to increase the reliability on opening by reducing the likelihood of lineovers as well as improving on-heading performance. This packing method is usable for both SL-up and SL-down/off jumps.
The idea behind the Tail-Bury method is that one of the factor improving heading and reducing lineovers occurence, being it SL up or down, is the "Nose-First-Inflation".
In the ideal case, you want your canopy to deploy laterally first at the leading edge, center first (so rolling the leading edge is a good idea as well), then the rest of the canopy follows it keeping the already defined axis. The tailgate is promoting this while keeping the tail alltogether while the leading edge expands on prior phases of deployement.
The worst case for lineovers is when the tail begins to partially inflate before all the rest of the canopy has properly expanded and tensioned all the lines on the way. That's where the idea of rolling or burying the tail in the center of the packjob makes sense.
Now one of the factors inducing offheadings is when one side of the canopy inflates before the other one. Especially the outer cells. But usually if the center is already inflated in the proper axis, the canopy tends to keep it. Rolling the nose tightly and having a huge open center cell, as well as packing the front linegroups a little bit wider than the other ones will drastically promotes a nose-first-center-first inflation.
HOW TO
A. Start by a classic PRO-pack.
B. Prepare the leading edge openings as usual (sides rolled / wide-open center cell) and do the 3 side-folds as usual, but don't fold them in half towards the center. The packjob is still "large" (2x times larger than the container)
C. Set your direct-control if you use it.
D. Set a Tail-Restriction setup (tailgate, slidergate or similar methods)
E. Flake the tail on your still "large" packjob (fig.1)
F. Make two 45° folds on the bottom of the canopy, with all the 3 side-folds alltogether (fig.2)
G. Place the tailpocket correctly, adjusting it to the bottom of the packjob (so it just covers the slider when packing slider-up)(fig.3)
H. Stow you lines as usual (you can do it later as well but it's easier to do it now)
I. On each side, grab all 3 side-folds AND the flaked tail. Fold all that alltogether towards the center in half. (fig.4)
J. Fit your packjob into the container
[Image1_large]
fig.1
[Image2_large]
fig.2
[Image3_large]
fig.3
[Image4_large]
fig.4
Pro's and Con's
Pro's
- Reduce the occurence of lineovers
- Improves heading
- Faster and easier to pack
Con's
- None reported yet
Facts / History
Martin Tilley developed this method sometime in the 90's. For this reason it is sometimes referred to as the “Tilley Fold.”
460 reports "I have an old school friend, BASE 175, who never had a line over when jumping slider down prior to the discovery of the tailgate. He did something he called "packing the tail into itself" that he learned from BASE 74. When I met him, he had 120 slider down jumps. Funny thing was that he also never had an off-heading opening."
Some other jumpers ended by doing the same method on their side while trying to improve the classic-method, and had the same conclusion about the effects of it on opening.
Nowadays, it seems to be an improvement of the classic PRO-pack. The use of a tail-restricting setup is still strongly recommended and present only benefits on staging the opening.
Other aspects
There's a discussion about the dangers of using the LRM (lines routed outside of the grommets) when jumping SL-down VS the pro's of LRM (ability to deal with a lineovers)
There's been accidents where people lost a toggle after a normal openings because of the LRM and had to land a canopy with rear risers. Whatever the skill level, it's always easier and safer to land with both brakes!
Nowadays given that :
a) we now have some good models of LRT (line-release-toggles) on the market
b) with the tailgate and a proper packing, the likelihood of lineovers are near zero
then more and more people stop using the LRM on SL-down jumpe because they feel that it's overall safer (note that this might not apply to every jump).
Packing
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