Snivelling Rounds

[guest]

Serious technical question so ignore as usual.

Anybody have info on rounds that snivell? Ive seen two rounds that snivelled, leading to two jumpers impacting deep water at high speed. Not on same day or with same canopy. Both jumpers ok, although one doo-dooed himself.

Video inpection suggests that the lines just below the skirt may have twisted slightly, delaying inflation by 50'. The canopies were straight with no packed line twists. After snivell delay, both canopies began inflation process and impacted at maybe 75% inflation. Enough to cause some deceleration but still estimate impact at 50 mph or so.

Anybody?

[base428]

(1) did you rubber band the apex to speed up canopy inflation?
(2) was adequate canopy inflation time accounted for? rounds are, of course, slower on inflation.
(3) block cut vs. bias cut is also an issue with some jumpers and round canopies. it basically refers to how the "grain" of the F111 is arranged, either helping or hurting the folds of the canopy.

Rich S. taught me about rounds in 1995 and gave me a round packing tape. it's a good resource for clean round pack jobs....

jason bell
jbell@vertical-visions.com

[imported_Tom Aiello]

Had the diaper been removed? Or was it left on the canopy but not used?

I wonder if the weight of the diaper could have misaligned the skirt and contributed to the snivel you describe?

--Tom Aiello
tbaiello@ucdavis.edu

[crwper]

Can you comment further on the difference between block & bias cut for BASE jumping? Thanks!

Michael

[base428]

I don't personally own a "bias" cut round, but there are problems with them. Bias cuts on F111 are arranged so that the edges of the small F111 squares are at 45 degree angles to the folds of your canopy. On "block" cut canopies, which I do own and jump, the sides of the F111 squares are in line (parallel) to the folds you'll be putting into your canopy. The bottom line is that it's easier to fold a block cut canopy than a bias cut. Bias cuts don't maintain their folds as well and they can make for a messy pack job. So if you're looking for a new round, make sure it's a block cut.
This topic can get pretty deep, but I hope I've at least helped a bit. Good luck.

Jason Bell
BASE428
jbell@vertical-visions.com

[guest]

The first canopy was a Phantom 24 with the diaper still attached, but not used. It was rubberbanded at the apex and there were no 45's on the skirt. Less than 2 sec. delay from 300' stowed w/45" PC. It was the first jump of the day on this canopy(it was completely dry). Bias cut.

The other canopy was a preserve 22 or 24 with the rubberband on the apex. Diaper was removed. 300' hand held. Just under 2 sec. delay. No 45's on the skirt. 46" ZP-PC. It was the second jump that day on this canopy. The canopy was completely dried before packing, but there may have been some moisture in the container. I believe the Preserve is bias cut, but I'm not sure.

On both rigs the lines were stowed in the container in loose rubber bands.
Both pack jobs were very well done(clean)

PS. We now have several complete round rigs for sale:P

[guest]

I seem to recall from my rigging days that both Preserves and Phantoms were very easy to pack, which leads me to believe they are block cut. The only bias cut canopies I recall dealing with were C9s, various other military canopies, and Security rounds, though obviously there are many other bias cut canopies out there.

[imported_mknutson]

I found a Phantom 24' for $100.00 but it has a snag in one of the stitch lines. Is that hard to fix?
Is it worth $100.00 bucks then?

[guest]

I guess that maybe I'm not clear on the difference between bias and block. Could you explain it? I thought that the bias seams were sewn at a 45 to the skirt and that block seams paralelled the skirt. I've packed the Phantom, Preserve, C-9, SAC and Eagle and they all seamed very easy to pack. I couldn't tell a difference.

[guest]

Ok, theres some good info. I do think the two rounds were block cut but dont have either in front of me to inspect.

About delay, the object is regularly jumped with a 2+ delay with rounds, sometimes opening 20-50' off the deck. I guess rounds are a little less reliable and we are just shaving too much off the margin.

Maybe this should have been my question: When packing no diaper/hesitator and stowing suspension lines in the pack tray, is there a tendency for the lines to become disorganized, temporarily choking off the skirt? Is this a case for tighter rubberbands or a larger pilot chute?

thanks!

[imported_Tom Aiello]

>Is this a case for tighter rubberbands or a larger pilot chute?

A round should be less susceptible to problems caused by an oversized pilot chute. Most of those problems result from center cell strip, and that doesn't really apply to rounds.

--Tom Aiello
tbaiello@ucdavis.edu

[346]

This sounds very similar to some video I shot maybe 8 years ago, but neither jumper was stowed: The first jumper off (with a phantom) did a go and throw. He experienced a slower than normal opening because of a half line twist just below the skirt. The opening pushed the twist down the lines and spun the jumper 180 degrees. This spinning action caused his legs to fly out to the side and induced some oscillation to the canopy which he rode into the water.

I don't know whether he had the diaper on the canopy or not. I know he did not use one on this jump. I think he was into using rubber bands in the container.

I don't know that we ever tried to analyze it more than that. We were happy because the video was entertaining!

Mark &-)

[460]

If the parachute is already out, doesn't it seem to you that increasing the upward force (aka a large pilot chute) on the apex would only hinder the speed of the opening?

What about Taschengurt's to improve the opening?

-Chris



>>Is this a case for tighter rubberbands or a larger pilot chute?
>
>A round should be less susceptible to problems
>caused by an oversized pilot chute. Most of
>those problems result from center cell strip,
>and that doesn't really apply to rounds.
>
>--Tom Aiello
>tbaiello@ucdavis.edu

[guest]

those only work in Germany. it's a known fact that in other countries they serve no purpose other than to provide a place to wedge in a can of red bull while you are packing in case you get thirsty.

[base428]

Perhaps a can of GO FAST would be better? Or havent' you heard yet?

>wedge in a can of red bull