Just when BASE jumping starts to seems cruel and cold and soulless. You are visited by something that restores your faith, something that shows you the sport is not just on the move, but on the move in a hurry. That something is called "ATTACK of the BLEEDING AUSSIES!"
And now our little wall is freefallable.
"You must throw the pilot chute "up" not "out."
Wow . . .
Thanks Slim and Dwayne . . .
BASE jumpers are the coolest people in the world.
Nick_BR :-)
Just like a mother in law....fun to have visit but when she moves to your town......
In the last two years we've legalized physician assisted suicide, medical marijuana and now this...
Portland will never be the same
need to buy big pilotchute. ;-)
is it really make a difference to trough it up and not take it out ??
c ya
>is it really make a difference
>to trough it up and
>not take it out ??
>
>
>c ya
Absolutely!
Waiting 1 second, you already have enough snatch force to pull you canopy out. You can throw to the side and then you have to pass you pilot chute before you tension your shrivel flap. By throwing upward, it is tensioned immediately. It is almost like a PC assist. For super low stuff, the difference between 1 second and 1.5 seconds before canopy extraction is important.
Other tricks for low altitudes -- you can get a quicker opening using shallow brake setting (yes, more dangerous on a wall) and using less velcro on your shrivel flap. For the really low stuff I've done, I put napkins in the middle half of my shrivel flap so the velcro doesn't mate except for the top and bottom few square inches (be careful here!!!) Also, my experience is that the propack opens slightly slower than the side pack. The extra fold in the propack to make it narrower can make a difference. 170' is about the lowest I believe that can be safely freefallen over land now.
Does this mean Simon J. will now join the Aussies on the dark side?
MG
I usually just use a pin rig for that kind of thing. I'm also a believer in the "easier to open" school of thought that leads to the half mated velcro (I've done that too), but I've found that the pin rig is really the fast opening champ.
--Tom Aiello
>Does this mean Simon J. will now join the Aussies >on the darkside?
That deed is done. And I have a feeling it will be done again and again and again . . .
Nick_BR :-)
>And now our little wall is freefallable
That little wall still has not been shown the respect it deserves. It has so many possibilities. Just wait for our next visit...
In response to a few other postings on this thread:
In my experience, shallow brake settings do not create a faster opening during slider down deployments. Shallow brake settings will slightly inhibit the cell pressurisation when compared to deep brake settings. Shallow brake settings WILL however give you forward speed at an early stage and therefore the canopy will be landable sooner after bottom skin expansion. For this to be of any benefit you would need to be opening LOW (my definition of low). So unless you're freefalling from below 140' over hard earth then I would personally pack in deep brake settings.
It doesn't hurt to prime velcro, especially rigs with 1.5 inch velcro on the side flaps.
For pin rigs, be aware that pin tension on the closing loop various greatly from pack job to pack job. Also the pin tension can vary by where and how you place the stash bag in the backpad and by how much clothing you are wearing. In summary pin closed rigs can require less force to open than a velcro closed rig, but it is also easy for the opposite to occur. Don't just check the pin tension when the rig is on the ground. Have someone check it when you are geared up.
I wouldn't encourage most jumpers to freefall objects (esp walls) below 200'. In order to do it on a regular basis with any reasonable chance of success you need gear knowledge and skills well above that of many BASE jumpers. The chance of a 180 off-heading makes this type of jump a crap shoot unless you have specialised emergency procedures pre-determined to jumping.
And finally 170' is by no means anywhere near the bottom end of what can be freefell over hard earth. With specialised equipment and specialised techniques, the boundaries are somewhat further that what most people would expect.
Thanks to everyone at B.R. (esp. Annie) for a great visit. Back to Portland now to make Nik's life hell....
> 170' is about the
>lowest I believe that can
>be safely freefallen over land
>now.
I know of 120' over land done more than 12 years ago. It's nothing new, and it has not "evolved" into a safer endeavour.
Low freefalls are a personal challenge and often an egotistical massage.
Sure, 170' FF is possible.
However, it is not safe. It's a personality disorder.
1) Is there not a greater danger of throwing the pilot chute into your burble especially at these low airspeeds.
2) How exactly is the throw different
Basically, can someone expand on the specifics before some fool tries this without knowing the hazards.
MT
you mentioned "priming velcro." never heard this term before. i assume you mean using less velcro surface area to hold the parachute in the container.
you also mentioned that shallow brake settings didn't encourage cell pressurization in your experience when doing a short delay slider down. I thought cell pressurization occurred when air passed over the top skin of the canopy after bottom skin inflation. Seems like more forward speed would increase cell pressurization rate. Is the current model (aka Filippino) of cell pressurization wrong based on the data (your experience)? i have a hard time saying because i don't have video and the jumps were at night. how canopy dependent (including the actual slight variation of brake settings of different canopies) is this rule? I have some ideas on how to increase cell pressurization rate using a specially modified canopy with some bottom skin inlets.
some of the fastest openings i've seen were done without a tailpocket. there is less weight for the pc to drag. in addition, the center cell stripping is less without all those heavy lines held at the rear of the center cell. the lines were actually either 1) controlled with baby ponytail rubber bands, with 8 to 10" segments layed in the bottom of the container, or 2) stows were placed in the container similar to a round reserve setup, with baby rubber bands used. what are you thoughts about this?
how about pilot chutes? i use a 49" (measured) ZP PC. I hold it a special way very very tight. it actually is about the size of a man's fist before launch. it's so tight, it springs open almost like it's already inflated when I throw it, even in dead air. (depends on your pilot chute. some pcs spring open much better than others) using this method and throwing straight up one moment after launch, deployment looks like a PCA. your thoughts? your holding method? any problems with pilot chutes that are too large?
how do you deal with a 180 or bad off-heading when going this low? I've had one 180 on a very low jump and knew it was coming when I launched. I fixed it unstowed brakes and landed. no problems. below 200 though, what do you do??? rear risers to turn it as much as needed and land with brakes stowed?
for these low jumps, I'm covered in pads. they seem more like controlled crashes, where you may be using you need pads to do a landing.
460
In response to questions from #460:
>
>you also mentioned that shallow brake
>settings didn't encourage cell pressurization
>in your experience when doing
>a short delay slider down.
> I thought cell pressurization
>occurred when air passed over
>the top skin of the
>canopy after bottom skin inflation.
> Seems like more forward
>speed would increase cell pressurization
>rate. Is the current
>model (aka Filippino) of cell
>pressurization wrong based on the
>data (your experience)?
An extract from an article Adam Filippino wrote a number of years ago titled 'The Importance of Deep Brake Settings':
"During slider down deployment, the lower surface experiences complete and instantaneous inflation before the airfoil even begins to pressurize. Any canopy will deploy in a more stable fashion, experience less oscillation due to suspended weight shifts, and have a reduced tendency to surge forward (which usually only helps close off the leading edge due to the fact that it hasn't aquired sufficient internal pressure to stay open against external pressure) if its lower surface has a more positive angle of trim and a more concave profile."
In my experiences I would strongly agree with Adam's comments. The initial surge forward upon bottom skin expansion can make the nose fold under itself and inhibit cell pressurisation.
>how canopy dependent
>(including the actual slight variation
>of brake settings of different
>canopies) is this rule?
The term deep brake and shallow brake settings are often mis-used and mis-understood. They do not simply refer to the two different brake settings commonly found on a BASE canopy. They refer to a brake setting that is dependent upon your weight, the altitude you are jumping and the canopy type. The deepest setting currently on your BASE canopy may be the same as the shallowest setting on another person's canopy who has the same equipment and weighs the same as you. You would call this setting deep while your peer would call it shallow, when infact they are identical settings.
>I have some ideas on
>how to increase cell pressurization
>rate using a specially modified
>canopy with some bottom skin
>inlets.
This is not a new or revolutionary concept. The key questions here are: "Where on the canopy is the best place to put the inlets?, How large and how many inlets should be used?, What negative effects will this have? Are valves needed to reduce the negative effects? etc etc.
Accuracy jumpers used to cut a circular hole in the bottom skin of cells 3 and 5 to improve their deep brake approach.
>some of the fastest openings i've
>seen were done without a
>tailpocket. there is less weight
>for the pc to drag.
The p/c still has to lift the same amount of weight through to line stretch regardless of whether the lines are stowed in the tail pocket or in the bottom of the container.
> in addition, the center
>cell stripping is less without
>all those heavy lines held
>at the rear of the
>center cell.
If you are worried about center cell strip at low airspeed then I would suggest using a multiple bridle attachment system. This will support the tail pocket and prevent it from slumping lower than the rest of the canopy.
>the lines
>were actually either 1) controlled
>with baby ponytail rubber bands,
>with 8 to 10" segments
>layed in the bottom of
>the container, or 2) stows
>were placed in the container
>similar to a round reserve
>setup, with baby rubber bands
>used. what are you
>thoughts about this?
There are a lot of benefits to the tail pocket which I won't go into here. I personally have had some very nasty results freestowing lines with a square as you outlined above. It works great with a round deployment though. This is because there is a common reference point to all the lines with a round (as there is not on a square). There were some pretty strong reasons why BASE jumpers started using tail pockets on free-packed rigs.
>how about pilot chutes?
We could have another entire thread purely on pilot chutes for very low airspeeds. Size, construction techniques, number of load tapes, orientation of the mesh, 2 dimensional p/c's versus 3 dimensional p/c's etc etc.
>Any problems
>with pilot chutes that are
>too large?
Yes - deformation of the canopy when it is flying. I found a 52"zp p/c will create a noticeable loss of performance on a single bridle attachment canopy (it will still fly and land fine though).
>how do you deal with a
>180 or bad off-heading when
>going this low?
Basically I try to avoid the wall and hit the ground as softly as possible...
From a 170' freefall you will not have enough height to turn the canopy around all the way from the wall and still land reasonably softly so don't try and do so. A turning canopy will hit the ground harder than one that is flying level or sinking almost straight down. Turn the canopy enough so that you don't hit the wall and get ready to perform one hell of a PLF.
To pull this off without injury you will need to be a very very impressive canopy pilot (or very very lucky).
>I've had
>one 180 on a very
>low jump and knew it
>was coming when I launched.
> I fixed it unstowed
>brakes and landed. no
>problems.
It wasn't a very low jump if you had time to do all of that. :)
It's nice to see jumpers thinking a little about equipment rather than just blindly accepting.
A stolen quote: " Gaze not too long into the abyss, lest the abyss gaze into thee..."
Translating, reality checks are as important as gear checks.
Yo
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