Low Freefall PC Throwing Techniques - SPLIT THREAD
Tom, can you please write up a real quick technique for hand-held, low-freefall, PC throwing techniques? From what I've gathered from other posts, it seems that it is similar to throwing it forward and up?
Also, I downloaded Johnny U's Super mushroom technique, (http://www.johnnyutah.com/supermushroom.html) and played with it on a cold, snowy day. I think it is a super method of reducing PC hesitations, especially low handheld jumps.
I've made quite a few low freefalls with the Dwain/Slim "throwing up" technique. In my opinion, it's quite good (because it gets the PC to bridle stretch just as you step off), but it still experiences occasional hesitation (which can be very frightening at low altitudes).Originally Posted by baseninja
My current preferred technique (my views are continuously evolving, so I may change my mind in a week, month or year) is to "loft" the PC upward so that it is fully inflated as I step off.
You can see what I mean in your living room:
1) Take the PC of your choice (for this technique, bigger is better, because you don't have to worry about hesitations).
2) Grasp the PC at the bridle attachment point. Route the bridle out the top of your hand (so that you won't tangle it with your hand as you release).
3) Swing the PC back and forth a few times to get it all stretched out, and build some momentum.
4) At the front/top of a big swing, release the PC so that it "lofts" above you. The PC should be fully inflated just after it stops moving upward.
Here's the caveats (which is the primary reason I won't really be discussing this technique say, over on DZ.com):
a) Don't throw the PC too hard, or the upward motion will deflate it. You want to get it just high enough that it's over your head, and fully inflated. Fortunately, you can practice this in the safety of your own home to be sure you get it right at the exit point.
b) You must use a short bridle. Using a standard length BASE bridle will leave you with a giant mess of slack bridle as you exit. The potential for a bad outcome from this chaotic mess is quite high. You want the bridle to be as taut as possible between your back and the PC at the moment you exit. I've played with various bridle lengths, and, at the moment (see above disclaimer regarding my right to change my mind) my preferred bridle is approximately 4 feet long. As a side note, there is no need to worry about "getting the PC out of the burble" because (i) you have zero airspeed and hence no burble, and (ii) regardless your burble can't extend above your exit point, and your inflated PC will be out of any theoretical burble (because it's above the exit point) before you exit.
This is not original work on my part. When I started playing with this, I asked Dwain about it, and he mentioned that Nic Feteris had shown him this technique, which had been used to successfully freefall very low (by the standards of that day--sub 250') objects on converted skydiving gear in the 80's. At the time, many folks were using skydiving bridles anyway, so there was no conversion of bridles to do this.
Please do post any questions. Since this technique requires non-standard gear, I'd prefer that everyone who wants to try it be very clear on what I'm trying to say.
I think the super mushroom is less prone to hesitation that the other PC packing methods I've seen. If you're going to pack the PC (in your hand or BOC pouch), I'd recommend it.
Tom Could you do your ,example 9ft bridel, as a SL whith a rubberband and do it that way instead?(even as its easy to make a 4ft bridel)
i do agree that tereticly you will have 0 speed=no buble but if the pc hesitates(even shortly)you could(teoretickly) get a problem i guess..
How low did you use this tecnice?
I'd guess so, but I haven't tried it. If the rubber band was too loose, the bridle could unstow during the process, and that would put you lower than otherwise (it might also do other bad things). And I'm not sure how I feel about having a weighted bundle somewhere in the middle of my bridle.
148 feet. I think that we're approaching the point where the important differences are happening in other parts of the system. If you want to go below 200 feet (and otherwise, why bother using this technique), you really need to be sure to look at all the other elements of your system, too (like: closing loop material, bottom skin inlets, canopy size, etc, etc, etc...)
This is a new way(to me) on how to do thouse kind of jumps..
I havnt freefalled below 180ft so far(and not sure i will),ive started to do as Spence does (upwards through whith mushroompacked pc and 9ft bridel),which i found as a good tecnice aswell,aslong as you care to do your pc eash time(ie not just grab it from the BOC),i found that(even as its hard to me to see,that timed,you can nealy get bridelstrech(9ft bridel)as you jump,if done correct..
Is there any way Helium balloons could be used to lift the pc with a 9 ft bridle? It would alter the PC behavior, and most likely the opening and flight of the canopy (similar to OVER-sized pc's 70+" .)
OK, why not just use a helium balloon as a PC?
Thomas
The helium ballon would have far less drag than a PC, so it wouldn't extract the canopy effectively. You'd have to hang a PC from the balloon, or build a PC "skirt" around the balloon.
Interesting idea, though...
The thing is that I am envisioning a different type of set up. Not just a helium balloon, but a BIG- ASS size helium balloon. LIke, a 2.5 m diameter balloon. With such a set-up, the lunacracy of the situation would require some sort of "Excessively-Sized-Balloon"---cutaway system.
But those details can be worked out later.
Thomas
p.s. When can we discuss the self inflating canopy?
i think if you calculate youll find that balon too small to pop your pins anyway...The thing is that I am envisioning a different type of set up. Not just a helium balloon, but a BIG- ASS size helium balloon. LIke, a 2.5 m diameter balloon. With such a set-up, the lunacracy of the situation would require some sort of "Excessively-Sized-Balloon"---cutaway system.
But those details can be worked out later.
Thomas
p.s. When can we discuss the self inflating canopy?
hope its an out side climb or it could be a bitch to jump off an A
I'm looking for some numbers on lift capacity. What I am thinking, is that the helium balloon will act as the PC, and open the container, lift the canopy off your back, and pull it to line strecth.
At which point, lift capacity becomes an issue.
If lift capacity of the balloon exceeds your weight, then ride it up to altitude.
Which has actually been done before, not quite with the same intention.
Larry Walters
The self inflating canopy would fire open like an air bag, and essentially be a closed canopy that is pressurized with gas. Vents or airlocked canopies could be used as variations for transition to flight from pressurization.
Once again, the lifting helium balloon would have to be cutaway, for any possibility of canopy flight.
Thomas
Thomas
i think your helium ballon is really bad juju...
why?
did you ever buy a heliumballon? how much force do you need to pull it towards you?
Now how much force do you need to pull out your canopy?
but you could use it as a drouge,the climb will be a bitch through
Tom do you have any video of the shortbridel throwing up jumps? i would like to see so,you could mail it(max 10mb).
Im making myself a 4-5 ft bridel one of theese days,and will test it out in the future
>b) You must use a short bridle.
How much people use shorter bridle for low FFs?
How comon is that?
I'we read all tehincal post at BB (and DZC) but haven't notice remark about short bridles for low ffs.
Thanks :-)
to use Tom´s way(i first heard this from Tom,i dunno who did it first or last
You´ll need a short bridel as you cant through up a pc to the bridel is streched (if its a 9ft bridel),the idea is that as you jump whith a inflated PC whith no delay(no buble behind you) a 4 ft bridel should be good for this.
i GUESS that a skydive bridel is about that lenght(im not sure and dont have any to meassure)
It's not. Which is why the "throwing up" technique is better for 99% of BASE jumpers.
I know how to use shorter bridle (and why), but I was wondering how much people actually use shorter bridle for low ffs. And if so, wht leght is bridle?
Thanks,
I.P.
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