0
pchapman

Short bridles on round reserves still normal?

Recommended Posts

Traditionally the reserve bridles on round reserves were quite short. (e.g., 4 ft)

Would that still make sense as current practice?


I wonder if a slightly longer bridle might help the PC clear any burble easier -- by letting it jump further. And maybe even occasionally avoiding the PC from being 'held back' for a moment just as it is about to escape the burble.

The most common use of round skydiving style 'reserves' at the moment is pilot emergency rigs. I haven't seen enough recent ones lately to recall what kind of bridle lengths are used but I think they still remain relatively short. (And haven't gone through all the bailout rig manuals.)

But how much of the short bridles is just tradition, and would one design or even pack a system differently today?


===========
More details and thoughts for those that care:

Now we don't need the often around 12' (?) bridles as became common with the square reserve freebag system in order to provide for its anti-horseshoe rationale.

Once a nominal 4' bridle is attached and the top of the canopy is stowed in a certain part of the pack, crown and crown lines tucked under as in many packing instructions, only 3' of the bridle might be really free to extract with really low drag.

I just popped an old 2-pin piggyback rig open for a repack and I wasn't too impressed with the pilot chute launch because it came to the end of the bridle so soon. The PC is an old 357 Magnum so not like the stronger modern reserve PCs. (But strong ones don't always work with old rigs -- I tried a Vector reserve PC on an old 2 pin rig and its strength really distorted the flaps, and put a lot of stress on the backpad too, built in an era with plastic reinforcement around the closing loop base area rather than solid aluminum plates these days.)

Modern skydiving reserve systems don't always have a ton of bridle set up for instant extraction unencumbered by flaps either, often 3 1/2' to 6', but there's plenty more ready to be staged from under flaps.

There are exceptions of course. On the one hand nowadays many bridles are tied down with seal thread at a certain point -- Skyhook equipped rigs -- while a rig like the Javelin had the bridle packed for decades (not now) without any bridle tucked below a further level of flaps.

Round reserves nowadays don't have open mods so a pilot chute won't get caught in them causing a mal, as with the turn slots on a fast flying ParaCommander. So as long as the bridle didn't get so long that it could drop the pilot chute down around the canopy skirt it would be fine.

So would a bridle of maybe 6' or 7' be better overall?

One could also wonder if a wider bridle (2" or 3") would be better than the typical 1" square weave. While wide bridles don't magically extract freebagged reserves, their width may give the bridle a little stability and less likelihood of knotting up in the air. But that's quite debatable too, to what degree it helps.

Share this post


Link to post
Share on other sites
"Once a nominal 4' bridle is attached and the top of the canopy is stowed in a certain part of the pack, crown and crown lines tucked under as in many packing instructions, only 3' of the bridle might be really free to extract with really low drag."

I still don't know why they say to tuck this stuff under. The guy who taught me rounds just said to do it but could not explain why, which I did not like as I didn't like doing stuff "just cuz".

Someone told me it had nothing to do with opening performance, rather it was about protecting that area from abrasion from the container cordura. Idaknow.

I was rigging for like 5 years before I finally had one of my round repacks deployed, was happy to see it worked.

__________________________________________________
What would Vic Mackey do?

Share this post


Link to post
Share on other sites

I've packed mostly rounds for the last several years and most if not all of the pilot emergency rigs, including a couple of new ones and on in a free sleeve.. All of them still spec somewhere from 3 to 4 foot bridle. This includes the newest designs, Butler HX and Preserve V. For most of the rigs I pack the PC, including 357 magnums, hit the ceiling 4 feet away. I don't think there is a need for a longer bridle. I think there is video of a test jump of an Aerosports USA back on you tube. Anyway it leaves just as fast as anything. Of course they have to meet the same TSO deployment specs.

As for a wider bridle Booth once claimed the wide bridle was bad for launch. That burble air circling around the back actually hit the wide bridle and pulled it back down. (The whole room said 'fold and sew the first 6 feet narrower. ) I've got about 300 round jumps with spring PCs but most of those were a comp PC in sleeve so I had more issues.:P While I had some PC hesitations a lot of the PC's I used were really crappy. It was a good day when I finally got a Hot Dog.

I've got 3 round reserve deployments, only two count, and they were fine. A few years ago I jumped a Phantom 28 in a bag with a throw out PC on a 7 foot bridle. I was more nervous about the PC and bridle than anything because that was the only unknown.

For pilot rigs I don't expect them to be stable so don't think the burble is an issue.

Don't see the need and don't see a manufacturer doing drop testing to replace something that works.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

Share this post


Link to post
Share on other sites
Hi Peter,

Quote

Traditionally the reserve bridles on round reserves were quite short. (e.g., 4 ft)



Depends upon your perspective. When I became a rigger in early 1965 the standard length for bridles ( mains and pilot rigs ) was 3 ft. Back then almost all gut pack reserves were still being packed without pilot chutes. And those bridles were almost always just a length of 550 suspension line tied with a bowline knot on each end.

Quote

So would a bridle of maybe 6' or 7' be better overall?



Not in my opinion. For all of my PEP rigs, the bridle is 1" Type 4 and is 5 ft ( 1.5 meters ) from top of loop to bottom of the other loop.

Quote

Would that still make sense as current practice?



That can of worms is for you to deal with. Actually, current practise is whatever the mfr says to do/supply with the rig.

Any other questions?

Jerry Baumchen

Share this post


Link to post
Share on other sites
I am voting with Jerry Baumchen.
A 5 or 6 foot long bridle is plenty enough for round canopies. These days I only pack rounds into PEPs, and all those pilot chutes launch to the full length of the bridle before they hit the floor (zero air speed).

I also do not expect pilots to be stable when deploying PEPs.

Share this post


Link to post
Share on other sites
Thanks for the replies and opinions. Sounds like convention hasn't changed much .... although there is a desire by some of the riggers here to go a little longer, as numbers like 5 or 6' were mentioned.


@crapflinger2000:
I'm not sure about tucking under the apex either. I had gotten the impression it was to keep the mess of crown lines out of the way, off of the outer surface of the packed canopy. (Even if there isn't anything specific for them to snag on.)

Share this post


Link to post
Share on other sites
pchapman

I'm not sure about tucking under the apex either. I had gotten the impression it was to keep the mess of crown lines out of the way, off of the outer surface of the packed canopy. (Even if there isn't anything specific for them to snag on.)



Cosmetic. Keeps the outline (in dirt) of the upper lateral band from showing through the container, especially on single-layer flaps. The equivalent of Rigging Innovations instructions to put the reserve pilot chute spring swage at the 12 o'clock position, to prevent wear through a side flap if the swage were under a side flap.

Mark

Share this post


Link to post
Share on other sites
Funny!
Gary Douris told me bout a nasty round malfunction traced to an assymetric opening. Investigators blamed the assymetric opening on an assymetric apex. Part of the problem was that a tight bridle prevented the apex from self-centering.

Share this post


Link to post
Share on other sites

Hi Mark,

Quote

The equivalent of Rigging Innovations instructions to put the reserve pilot chute spring swage at the 12 o'clock position



I was there the day that Sandy & Geo. Galloway were making a video of packing a Raven into a Talon.

Sandy wanted the swage at the 12 Noon position but didn't know how to ensure it. I said, 'Why not just put an arrow on the pilot chute cap.' He took out his pen, put an arrow on it & the rest is history.

And I didn't even charge him anything. :)

Jerry Baumchen

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

0