Multi sheath for low stuff

[guest]

Do you leave it open or closed? I read on BR's site that open is the way to go. I have done jumps with it closed now at least 20 times on low stuff ranging from 170 to 260 ft. Most static lines.

What was the reason for leaving it open as I've never had any problems?

[crwper]

I've jumped with the multi closed as low as 111 feet static line without problems. I've done many jumps in the 130-140 foot range with closed multi, also without every having any problems. My lowest freefall is 210 feet, also with the multi sheath closed. No problem. I remember BR saying that the canopy generates enough force that even on the very low stuff, worst case scenario is that the multi sheath just shrivels up on the red line, and the velcro stays closed. Even on the very low stuff, the velcro on my multi is often pulled apart. If the canopy can get itself open, it certainly has enough force to pull the multi apart.

Michael

[BASE_689]

I think that BR suggests to leave the multi sheath open ONLY in case of static line jump, as well as not to exceed 2 wraps of rubber band on tail gate, still in static line jumps. My opinion is that the dividing range (of multi sheath open/close) is static line/free fall jumps.
The reason for this is that in static line jumps you DO NOT have enough vertical wind speed (and so, not enough "spreading" forces) to open up definitely and clearly all the times both multi sheath and (3) wraps on tail gate. There have been documented cases of static line jumps with 3 wraps on tail gate with successive (temporary) hang up of tail gate.
Something very similar could happen to multi sheath in case of static line jumps, because in this case are involved quite low wind speeds and consequently low "spreading" forces.
I have never done static line jumps, only freefall jumps in ALL of which I have always closed multi sheath, with altitudes comprising 112 m - 367 ft, 100 m - 328 ft, 80 m - 262 ft, 75 m - 246 ft, 65 m - 213 ft, with videos in nearly all of them, noticing NO PROBLEM AT ALL about opening of multi sheath, nor (temporary) hang up of 3 times rubber band wrapped tail gate.
Just my 0.02 €.
Stay safe out there
Blue Skies and Soft Walls
BASE #689 :D
NIGHT BASE #124 :D :D :D

[crwper]

I should also mention I've always used 3 wraps on the tailgate, even on the ultra-low stuff. Never had a problem with it, which isn't to say it can't happen, just it's never happened to me.

Michael

[d-dog]

I've taken three wraps of the tailgate on a 500 foot slider down jump and had a 1-1.2 second tailgate hesitation after a 2.5 second delay. Not a fun feeling - maybe it was just a fluke, but I had noticed on packing that the three wraps were pretty darned tight.

Now I do two on anything where I need a quick opening - I'd rather deal with a line over than smoke it into the ground with a tailgate hessie and a barely inflated canopy over my head.

Some assembly required; your mileage may vary.

Peace,

D-d0g
ddog@wrinko.com
www.wrinko.com

[crwper]

How far up the tailgate do you do the wraps? Usually I have very little tailgate sticking out past the rubber band.

Michael

[d-dog]

I used to be a bit careless about that, and now I always make sure to leave only a little tail hanging out. Based on my limited jumping experience, I think that does help a bit for slow-airspeed freefall deployment.

I've also heard that the manufacturers have a recommended pull force level that the tailgate setting should achieve before the lines are released. From what I've been told, anything more than that pull force is unnecessary to prevent line-over, and I believe could slow down deployment.

Anyone have data on this?

Peace,

D-d0g
ddog@wrinko.com
www.wrinko.com

[guest]

This maybe better for a new thread but...

I'd be very interested in finding out more info on people's experience/theories (not always related:) on tailgates and lowspeed deployments esp. freefalls below 250'. I currently have around 40 PCA/SL jumps from 300' and below and ON EVERY JUMP have wrapped the tailgate 3x. I have never had any hesitations (that I was aware of or caught on video on a MOJO 280 loaded at .8) and am interested in freefalling some lower stuff with the same setup. What do y'all think??
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[guest]

I think you're gonna die...;-) ...Signed:you know who

[imported_Tom Aiello]

>What was the reason for leaving it open as I've
>never had any problems?

I think that the reasons for opening the sheath and having a loose wrap on the tailgate at low altitude apply regardless of whether or not we can each personally report any problems.

I've never had any problems either. I've seen a couple, and heard about a couple more.

But, since I think the malfunction rate on this stuff is probably somewhere less than 1 in 1000, I doubt any one of us has a sufficient sample for any statistically relevant conclusion.

If I were to say "in my 150 jumps from under 300 feet" and use that as a justification, it would make about as much sense as saying "in my 150 skydives I've never had a malfunction, so why use a reserve?"

I just don't think we have the data (yet) to draw any meaningful conclusions.

--Tom Aiello
tbaiello@mac.com

[crwper]

IIRC, I was told by BR that it should take 15 lb to pull the tailgate apart, but I'm not really sure how one would go about measuring that.

Michael

[crwper]

For freefalls in the 200-foot range, I highly recommend a vented canopy. I'm sure a 200-foot object can be freefallen with a conventional canopy, but the canopy takes a long time to pressurize properly, and it's seriously going to eat into the limited time you have to make corrections.

Michael

[Tokemon]

I agree with Tom here, about not having enough data. Here's my little chunk of data for the collection. I have 10-20 freefalls ranging
200-300feet, and have used a tailgate on 75% of them. # of wraps I do varies on the rubber band I use. keep the ends trimmed within an inch, and normally 2 wraps with a skydiving rubberband cut in half lengthwise. after loosing a tail gate, I will use whatever small piece of rope I find, and whatever rubber band I find, and just put around same amount of tension in it.
of course, it gets hard to judge the tension when.................
Peace out,
Thomas:-) :-) :-) :-) :-) :-)