Disturbed Air

[base570]

How much of a Sickness is it??
If you have say 10 people that are going to jump an object as fast as possible, how much time do you allow between jumpers?? (all jumps are PCA or Static-Line and in the same spot or very close)
How much air is disturbed on opening and flying away and how will this "turbulent" air affect the next canopies opening, if any?
I once PCA'd 5 or 6 guys off a building in quick succession and didn't see much of a difference in their openings. They didn't notice anything either. Another time I watched 2 go off an "A" right behind one another and the second guys canopy had a hard time pressurizing and flying.
How about if your flying in an enclosed space like the cave in Mexico. I realize that there is a "wake" behind moving objects and that getting in them is not a smart thing to do but I'm interested in openings. Will they be lower, higher, left, right, unpredictable as hell, etc.

Thanks for your input
570 :D

[BASE 700]

Turkey day is near, I wonder what you have cooking?....did you get a chance to scope the huge ferris wheel at the fair this year...I bet those carnies would be pretty easy to bribe ;)



BASE700@comporium.net

[base570]

No I missed the Ferris wheel, how tall? Might be a nice new "A" (amusement park ride).
Gobble, Gobble your right Turkey day is near and hopefully we will feast on a sweet (virgin) object and give many thanks. So will you make it?? I still need to make one more "recon" mission, hopefully next week, to get the final details hammered out. Man, I can hardly wait!! :D :D :D
570

[base704]

Make sure that ya send some details my way too...
(as they develop) I have to say that this suspense thing is an interesting twist...
You're worrying me...
You've piqued my curiosity...
But, you're worrying me...:-( :7 :-(

[base570]

So nobody has any input on this??
Maybe if I phrased it differently I would get some quality input.
How this... bitch, bitch, moan, moan, I don't like you, your stupid; am not;are too; am not; are too.
Ah yes, that's what it takes to get some dialogue started, right??
;-)
Seriously, any input??
570

[base704]

...speaking of "disturbed air", I believe I have your stinkin' ass nasty hoof rotting Timberlands over here...or are they 698's? Either way, someone needs to claim these rotten fu(kers!;-)

[Thomas]

well since you used the magic phrase, I guess I might take a STAB at this one.
I would ask you about your experiences first. like, maybe:
EVER FLY BEHIND someone? CRW style in skydiving, but just following their canopy as close as you can? because, that might lead insight into this question. seriously, I don't know what the amount of SICKNESS DISTURBED air is, but I imagine it is a factor. like you said, ten people all exit the same spot, what is the wind situation going to be like.
Maybe DWAIN or SLIM or DDOG could share some info on this. as in, what do you think happens on big ways? like, the 22 way at bridge day? or the 8 way at Perrine? because that is A LOT of fabric SPREADING out in a small area. maybe someone has VIDEO evidence of turbulent air due to MANY canopies? how about that 24 way pulled of in NORWAY? how does this affect a TRACK? say, for tracking dives skydivng, or wing suit flights? maybe YURI or SPACE could share some insight into this, as they have MUCH MORE experience than I with a wing suit (0 jumps so far), but I imagine they are careful how close they fly to other jumpers.
well, hopefully if I can't help you, someone else can share some info that can.
I would just maybe ask you to TRY IT SKYDIVING, and see what results are. I'm not saying dump just below someone, or above them. that would be your own choice, and own decision.
or talk to any PILOT who flies in congested airspace. WAKE turbulence? is that what you are asking about?
ever seen the movie "Pushing Tin"? I doubt WAKE turbulence is THAT bad, but I wouldn't let a 747 land just in front of me. I have seen evidence of this at a drop zone. a skydiver came in to land near the runway shortly after the TWIN OTTER landed. well, half of his canopy folded under and then unfolded in a matter of 1/2 second. he was 10 feet off the ground, and luckily and skillfully pulled out some kind of flare, and actually STOOD it up. This happened at BALDWIN, WI when they had a TWIN OTTER there for summer.
I know now NOT to ever try to land where a BIG plane has just landed.
hope this helps.
Thomas :-) :-)

[Thomas]

for a side note, I might add this.
one would have to account for the jumpers surface area during freefall, and not just the canopy surface area.
as in, if one person were to jump behind K, and she is as wide as she claims, that would create MORE turbulence than say, perhaps s SUPER MODEL size butt on a BASE jumper.
but if I saw K wearing a BASE rig, she would appear to be a SUPER MODEL to me. as in, modeling BASE gear is hot enough for me. that is all I would see. well, maybe some of them big jug-ins also, but let's not get to worked up (pun intended) or distracted with the issue.
peace,
Thomas :-) :-)

[crwper]

Spence -- seems to me that on one jump, your canopy dove to the side slightly just prior to landing. That was definitely a turbulence effect, becuase your hands were level throughout the flare. In fact, it seems to me this hapenned on a couple of jumps before we smartened up.

570 -- I have quite a bit of experience flying in the wake of another canopy doing CRW and parabatics. The trailing canopy will become very hard to control because different parts of it are being stalled at different times. A couple of times I've been kicked out from behind another canopy at some completely unpredictable angle -- it happens very quickly, like a stall turn. I would avoid opening in another canopy's wake for this reason, if heading is critical (and of course you should probably be thinking of heading as critical if you're opening that close to another canopy).

However, the wake is pretty small, and goes up and behind the canopy during steady flight (not sure what it looks like exactly at opening). I can be flying directly behind someone with no problems, but if I'm about 15-30 degrees above and behind them, I'm going to be quite edgy.

You don't have to be close enough to be donig CRW, in order to feel the effects. A cameraman shooting some CRW I was doing (flying a Velocity 96, which obviously isn't going to respond to well to turbulence in the first place) found himself suddenly in line twists, because he was flying in deep brakes about 50 feet behind us and suddenly hit the wake. If you're flying in deep brakes, the turbulence just might make the difference between not-quite-stalled and stalled.

Michael

[base570]

I know about "wake turbulence" and such from messing around with CRW (maybe 75 jumps) and just flying around other canopies as well as reading some books on the subject, but what I really was interested in is how long it takes for the air to "stabilize" behind a jumper immediatly after opening. The object I am thinking about the heading performance is not critical (90 would be the worst) but a good flair and landing is essential since it is 180ft. I was just wordering about diving turns, stalls, etc. on opening. We need to get jumpers off as quickly as possible since security is ever present.
Thanks for the input Spence and Michael, if you have any more feel free to post it or email me
BASE570@Sub-Terminal.com
570

[crwper]

The 'S' Spence mentioned was 165'. You should be okay if you jump with a couple seconds between. It took Spence a few jumps to work down to two seconds' delay -- the perception is that you're going to fall through the other guy's canopy if you jump any sooner than that.

Michael