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If somebody can help -
I need max. different ideas about directbag and variants of packing.
May be - fotos or drafts...

What is the lowest safe alt to go with DB?

Sorry for bad English..

It's where the phrase, "You’re a hundred percent," came from. . .

I did quite a few direct bag jumps back in the day. My lowest was 130-feet off a building with a parking lot landing. Then we went right back up and my girlfriend did it to . . .

Direct bag fell out of favor replaced by static line and PCA. But from ultra low altitudes it works fine and if done correctly has a small chance of going off heading.

A couple of things - The bag should have color coded handles to make it more difficult for the bag holder to 180 the bag when removing it from the container. The bag holder should practice that move on the ground first. You also need to be careful when initially putting the bag into the container as garbage in – garbage out.

The bag holder needs to be secured to the object so they can lean out as far as possible and not be pulled over the edge if something hangs up. Also the bag itself should be tied off to the object if, shudder, the bag holder should drop the bag . . .

Many also attached a pilot chute to the canopy and stuck that in the bag too. "Just in case."

Call Karen at Apex she may help you with the schematics.

Here's some early photos . . .

NickD
BASE 194

Wait a minute now Nick. Didn't you do one off a 120' bridge somewhere is New Zealand?

Yes, but I broke both my legs on that one. I guess subconsciously I don’t think of it as my lowest jump as it wasn't exactly successful . . .

NickD
BASE 194

I was just messin' with ya. But all in all you did do a jump from 120' successful or not.

You can also make your own Direct Bag pretty easy. One problem with the older existing D-bags is they won't fit today's larger canopies. The coolest home-made one I've seen is made from a pair of blue jeans. You buy a size that's big enough to fit your canopy and cut the legs off below the back pockets. Then sew it closed. The belt loops are where the rubber bands go and the front pockets are the grippers. The only real "skill" you need is in setting a grommet in the crotch so you can secure the bag to the object, but you can also just sew an attachment point there instead. (Of course, make sure it will hold).

Some jumpers in the early eighties used shopping bags, but I wouldn't do that unless it was low and over water . . .

NickD
BASE 194

You can by one in http://www.crmojo.com/components.htm
And I'm sure it will come with packing instructions

Packing instruction a little bit difficult for me - I dont understant it without pictures....

For all -
how do youy pack them in.. I/m planing to make DB the same size as me pack tray in my Atmosphere, and thinking about how to stoof canopy in there...

Just like skydiving (with the same folds)?

Why not make the D-Bag with a Velcro flap on the top?

Then you can put it in the bag the same way you would put it in a Velcro container.

What are you jumping that you want to use a D-Bag instead of a PCA or static line?


Regarding your Q about how low you can go with a D-Bag.....

I would have though that other aspects of your setup and type of landing area are more important for how low you can go. E.G. canopy vented or not, water landing, bone density, etc.

We made a lot of jumps from brige 50 m (160 ft) by PCA, over the ground, that gives us about 2-3 sec of canopy fly.
Now we a planing to make some show with jump from bange-jump tower in the center of the city.
Alt - 40 m (130 ft), over the water. I can make PCA from there, but dont want to land in water - if I'll have 2 sec of canopy fly - I can land on ground (to not wet my lovely Ace 260, without vents or ZP top skin...)

I've never done any D-Bag jumps, but from our FJC and what I could learn about D-Bags:

- D-Bags are made like skydiving D-Bags, i.e. they have a flap with grommets for some mouthlock elastics and then tape loops for more elastics for linestows

- D-Bags are proportioned like the correct size base container for that canopy and the canopy is folded the standard way

- the canopies lines are not stowed in the tailpocket, but rather using the elastic stows on the D-Bag

- the D-bag should always be anchored to the object, in case the holder drops it

- the reason D-Bag deployments can be quicker than PCA or static line is that they achieve line-stretch before the canopy leaves the exit point

- some people remove bridle and PC for D-bag, some leave attached and some attach the canopy or PC to the inside of the D-Bag with a piece of break-cord


so you wouldn't want to make it like a container, as you gain most of the advantage by using elastic linestows on the outside of the bag and therefore getting linestretch before the canopy leaves the bag

cya
sam

edited for clarity and to replace 'static line' with break-cord

D-Bag's also deform the pack job less, since it's under zero tension after line stretch (where a static line or PCA still creates some tension from the bridle attachment point). This may lead to slightly better inflation.

Since the canopy is already at line stretch when it leaves the bag, I'm at a loss for what an additional inside attachment would achieve. Does anyone have a theoretical explanation of why such a setup would be desirable? I'm curious also if it's been observed to create faster openings in practice.

The late Frank Donnellan ( BASE 12) did some experimental jumps with Carl Boenish in about 1982 when he first met him and jumped the Crocker Tower in LA.

They direct bagged from a bridge only 60 feet above a river and just got bottom canopy surface before Frank hit the water. The pictures were hysterical.

theoretical explanation for that is easy:

same reason some people leave their bridle and PC attached for D-Bag jumps - they are not comfortable with the concept of the D-Bag and that you will get a canopy at linestretch before it leaves the bag...

I'd love to hear from people with loads of D-Bag experience on this topic.

also: do you use your tailgate when using a D-Bag?
the pros are obvious
the possible cons are a slower deployment ( maybe ) and the risk of tailgate hang-up
since you will likely be landing whatever sort of lineover or other malfunction you have when doing a D-Bag (if you use it for the altitudes D-Bags are intended for), is it really worth it to risk a tailgate hangup to try and prevent something you would not have time to fix if it happened anyway?

Dwain wrote a very detailed post on this topic. If you search the BLiNC forums, you can find it. I'll look later if I have a little more time.

The upshot was: Tailgates do not slow inflation. In fact, by promoting nose first inflation, they can actually speed up the process. I believe his line was something like "it's not tailgate = no line over", it's "tailgate = nose first inflation = reduced lineover and many other benefits", or something like that.

hey,

yes i recall that the lines are stowed on the bag not in the tail pocket. i was suggesting a velcro flap to allow the canopy to be put in the bag with minimal distortion, which seemed to be the concern.

having never used a d-bag i don't know how difficult it is to put the canopy in there without messing up your lovely pack job.

i'm still not convinced that it will make that much difference in opening altitude. can anyone who has done a bunch of D-bag jumps comment on how much sooner you have a fully flying canopy if everything else is equal?

Sooner than what? Are you wanting to compare to PCA? Or to freefall?

I have no trouble believing it opens much quicker than a freefall. I was referring to a PCA.

I don't think the difference between direct bag and PCA is very great, in terms of opening speed. I think that heading can be controlled more easily with a direct bag. It can also be screwed up more easily (just twist the bag) by an unskilled assistant.

D-bag opening are quicker than PCA's although only marginal. The canopy is held by the bagger therefore it is going to reach line stretch a bit quicker as there is no bridle. I have several D-bag jumps and the openings can be as much as 9ft higher, but not more than that, less if you short line the bridle.At ALL times using a D-bag it has to be secured to the object in case the bagger drops the bag(it has happened) Having said that there is not much use for them. To answer your question on velcro, yes it does have velcro to close it down the center as well as the flap to stow the lines similar to a skydive bag, however the bag is as big as your container. Packing is slightly different. I do not use a PC with it because to use a D-bag, if it doesn't work, a PC would be useless at those altitudes, less than 100ft.

The reason some attached the top of the canopy to the d-bag with break cord (which I don't like) was out of fear that instead of the canopy coming out of the bag a fold at a time it could just fall out in a lump. (And then stay that way too long on a very low jump). It may also have to do with the fact we are doing the same thing at the DZ as students are now jumping squares and we are first static lining them from airplanes. This assist device was in the USPA BSRs for sometime . . . and if I recall correctly it may have even been a FAR.

The big gripe in the early days with static line was it sometimes stripped the center cell from the pack job, it was complicated (to non-riggers) to rig, and to a lesser extent it left something hanging from the object. However, it was the Brits cursed with so many low objects, that proved it worked alright. However, most American jumpers here in the early eighties are still leery of it and preferred going direct bag.

There is even a whole big debate in the BASE community over if direct bag is worthy of being called a BASE jump. It was a time Rick Payne famously said, "I'd rather watch TV, than DeeBee." However, it "was" a common crawl before you walk method of making a first BASE jump.

PCA kind of started with an underserved bad reputation. Before we knew how to do PCA correctly we are seeing weird openings and off heading problems as the assisters are holding onto the pilot chute way too long.

As for direct bag packing method, remember the earliest direct bag BASE jumps are done before pro-packing is popular. They are done even before square reserve parachutes are in wide spread use so most squares for BASE are side-packed just like on the DZ. It was rigger/BASE jumpers, like Moe Viletto, that first correctly suggested we shouldn't be doing that . . .

The problem a modern direct bag jumper would face is you can't say they've been tested with the larger canopies, vented canopies, tailgates, etc . . . so be careful. If someone said I had to do a D-bag BASE jump tomorrow, in order to feel a hundred percent comfortable with it, I'd have to dig out the old Pegasus. . .

NickD
BASE 194

Can you elaborate on this?

As long as the PCAer stands directly behind the jumper and doesn't move his hand around, the only result from holding on too long would be center-cell strip, correct? Can this indirectly lead to heading problems or am I overlooking some other factor?

I'd rather have my PCAer hold on too long than too short on those jumps where PCA or staticline is justified.

I'm personally a fan of holding on to the bridle instead of the PC, but I don't think that affects opening characteristics much.

Thanks,

Jaap Suter

 

center cell stripping is a term used to describe deforming to pack job, not actual ripping of material.

And to see what happens, pack your canopy as you would usually and then right before closing the container yank on the bridle connection point while somebody else holds down the outerboard cells for a bit. The result is generally messy enough to make you want to repack.

 

Duh, I suck. First I ask:


And then I say:


Which answers my own question.

break cord is designed to mil specs., to break at or above 80-lbs. I can't imagine that a thin peice of cotton tape could hold enough to damage your canopy. Base canopies are built with extra load bearing tape through them to disperse these forces. However what strength it would take to do damage, would be a question for the manufacture.

D-bag jumps were the norm in my early days - here's what we found.

The break/cord link between the canopy attachment point was something we started using after a couple of jumps for the exact reason Nick said - we sought to hold the top of the canopy for a moment to the inside of the bag while allowing the bottom of the S-folded pack-job to snake out first rather than it all coming out in the air as one "lump" after the last stow released and having to unfurl in the airflow.

Because this break/cord was only used to retain the top of the canopy and not used to support the weight of the entire deployment, it only needed to be a lightweight breaking-strain. We used rubber bands or a single loop of lightweight twine for this purpose.

The tailgate had not been invented at the time we were experimenting and we chose not to use the Line-Mod as we thought the use of tight locking stows would negate this need - we were wrong. Upon watching all the videos of these jumps it was pretty consistent that the openings were positively TAIL-FIRST no matter if we packed on the side (factory) or on the nose (pro). With afterthought now I WOULD USE A TAILGATE for all these jumps although I would not wrap it too tight.

Also - make sure the safety bridle is not mis-routed anywhere. I happened to fluke survival of this most-basic and fatal error.

Canopy bottom-skin inflation seemed to occur after about 25-35 feet after the canopy had left the bag pretty consistently. Openings were always much higher than PCA although this is part due to do with the fact the canopy is deployed from the exit point and not 9' (bridle-length) down.

Heading performance was pretty much faultless. I can't remember anything more than say..45degrees off-heading EVER with this setup.

Overall - a good choice where off-heading = death or if you are getting off something ultra low.


g.

Last time I did a PCA jump, the holder got his fingers caught up in my pilot chute and I landed with some of his limbs still attached to my rig.

It didn't seem to affect my jump at all!