Wake Turbulence

[Spizzzarko 0]

I wasn't pickin on you, I just chose the last name on the thread to respond to.

[D22369 0]

no worries
Roy

They say I suffer from insanity.... But I actually enjoy it.

[murps2000 86]

lady's??? .... more like......"children"

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I was thinking more like biotches, myself (cluck, cluck).

When doing crw is there not more buffeting when traveling behind a canopy, than there is when making a dock? ***

Can I infer from your expressed beliefs based on this statement that you think you are in level flight when doing CRW? You're not. You're descending. It has been previously stated, but not yet disputed, that turbulence will not be felt directly behind the canopy producing it, but above and behind. Couldn't that mean that turbulence felt when your canopy is behind another might be produced by something lower than that canopy, like maybe the jumper under it?

Most sport canopies have a glide ratio of 3:1. Cross braced canopies like my FX have closer to 2:1. I don't know what a lightning has, but I bet it doesn't have the best glide. It's certainly no stiletto. And I've been told that CRW formations glide even worse. I don't know at what distance behind another canopy you felt turbulence when you were on level with it, but if you were 25 feet behind it (which is in the neighborhood of where I was when I have), you were probably feeling turbulence from something about ten feet below it.

Now, although I hope we're entertaining some people with our bickering (cluck, cluck), I really think we're wasting bandwidth. Let's face it, anything constructive that can be gleaned from this thread has already been said. In a practical sense, a jumper can pretty much remain indifferent to what is actually producing turbulence in front of him, as long as he knows it's there, and where he will encounter it. I think we all can agree that the phenomenon exists, and should be considered, if not avoided.

If you want to think that I misunderstood what I was taught, that's fine. I can only say that the course was in english, and I'm fairly fluent. I vividly remember the information, because I used to believe exactly what you do. When I heard different, I listened intently. Not only did I not know about the turbulence created by the jumper's burble, but up until that point, I hadn't even considered it. I'd lay decent odds that up until this thread, neither did you. But don't let that stop you from interpreting your perceptions however you like.

Safe docks & swoops, guys... (cluck, cluck...BGAAAWWK!...cluck, cluck...)

[Spizzzarko 0]

How much crw have you done with your FX? When I had my FX I did a fair amount. Enough to know that doing crw with these canopy's, is not the wisest choice out there. Most of my CRW was on the FX. Youj are making assumptions when you say that I said the turbulance was directly behind the canopy. Do you know what happens when you assume? You make an ASS out of U and Me. Mainly you though. What you are tought and what you actually experience may be two separate things.

[murps2000 86]

How much crw have you done with your FX? When I had my FX I did a fair amount. Enough to know that doing crw with these canopy's, is not the wisest choice out there. Most of my CRW was on the FX.

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I haven’t done any CRW with the FX. I kind of figured that it wasn't a great idea to use it for CRW without actually doing it. I did walk across the top of Tree's VX once, but we didn't dock. I think I was under a crossfire, but I can't remember which one I was borrowing of the two on the dropzone. That was two years ago. I dabbled in a little CRW when I had my spectre (four years ago), but more times than I can remember right now I've gone up and done some canopy freeflying & end cell bumping with other jumpers. Canopies I used were stilettos, my batwing, crossfires, and a velocity I demoed. I’ve caught wake turbulence of some kind three times. Under the batwing I felt the biggest hit when I was following Tree and a guy named Ford under a crossfire. I was a little ways back, maybe 60-70 feet, in full flight, and my body was about on level with their canopies. It really dumped the right side of my canopy for a second. Now, Tree's a big guy & blocks a lot of wind, but who knows? With that rag I was flying, maybe a sparrow came by and farted, or something.

Youj are making assumptions when you say that I said the turbulance was directly behind the canopy.

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This is the statement that led me to ask you if you were basing your beliefs on the turbulence being behind the canopy:

"When doing crw is there not more buffeting when traveling behind a canopy, than there is when making a dock?"

I know a few posts back you said something a little different about where canopy generated turbulence is, but remember, I'm talking to two guys at once. When I asked D22369 this:

"How do you know exactly what was generating said turbulence? Was your canopy behind the canopy in front of you when it felt pronounced? Are you both saying that you were feeling much less turbulence when your canopy was behind the jumper's body that was in front of you?"


He said:

"YES"

So I think for me to ask if you (meaning both of you) think you’re in level flight is logical, to an extent. I guess I don't really think that you believe that, though, given that the fact that we're all descending while under canopy is pretty evident. I realize it was a bit of an insult to say that, so I apologize. I just wonder how much thought you were putting into you're interpretations of what you experienced. I know now, after talking at length with a guy who builds parachutes and has twice as many jumps as all three of us combined, that I wasn't putting enough in when I came to similar conclusions about what I experienced. The first impression isn’t always correct.

Do you know what happens when you assume? You make an ASS out of U and Me. Mainly you though.

Yeah, okay. Look, I don’t need you in the equation to make an ass of myself. I’m perfectly capable of doing it on my own. And since you used the mean-face icon, rather than convince you of anything, I’ve obviously just pissed you off, so our debate degenerates further to being even less constructive. As I re-read the posts, though, I see that you said that you do agree that there is some turbulence behind a jumper, but you think there’s more behind a canopy. I said that I agreed that there is some turbulence behind a canopy but I think there’s more behind a jumper. However, in heated debate, I think our positions tend to polarize to a point where neither of us is right. Anyway, I realize I was a bit of a jerk the way I came off, so if I ever run into you at a dz, the beer’s on me.


What you are tought and what you actually experience may be two separate things.***

Yeah, that’s true. But also, what you perceive yourself to have experienced, and what you actually have experienced may be two separate things. There’s reality, and there’s what we think it is, influenced by our senses & thought processes.

And amount of turbulence and severity of turbulence are definitely two separate things.

[MathmatiC 0]

Bottom line. if you stay above a persons glide path(flight path) You will not hit turbulence. Same if you stay below. i am referring to the canopy "glide path"(the air the canopy in front of me was recently in)Not just the thing in front of me(someone under canopy).. Two completely different things. Visualize we use it all the time so apply it.

What to take away. Land to the side, above or below a glide path in front of you." if you are landing in close proximity." Dissipation of this can happen quickly so dont get too rapped up.

Also, wake turbulence is mostly from the lift producing wing above your head not the body dangling from it. Thats why wake turbulence becomes damn near nil after a 747 has its wheels on the ground but is still traveling at over 100 MPH and no longer be producing wake turbulence at a significant value.

[morris 0]

And even more important:
What happened to Spizzzarko?
Just realising we are missing him here...

[billvon 2,396]

>It slices the air more cleanly than the pilot

There are some common sense rationalizations that make sense when applied to things we understand (like a knife slicing through something) but don't work areodynamically. A wing generates FAR more turbulence than a draggy body, because the processes that generate that lift require a significant disturbance of air. This is expressed as a strong vortex that is shed from the sides of the canopy.

A good example of how counter intuitive this is is heavy aircraft wake turbulence. From our experience in the world of solid objects, you'd think that the worst wake turbulence comes from things that are:

-fast; because the faster something hits you, the more it affects you

-dirty (i.e. flaps and landing gear down) since there's more "stuff" to rile up the air

Yet pilots know that the worst wake turbulence comes from heavy, slow, clean aircraft.

We see this problem in other places, like in the thinking that "a faster wing just slices through turbulence" - but again, pilots know to slow their aircraft in heavy turbulence to avoid overstressing the airframe.

[billvon 2,396]

>The lead canopy was a Jedei and the trailing canopy was an 84 Velo. It turned the Velo into a dishrag...

We had a similar event at the bigways at Perris today, and it's the third time I've seen a Velo just fold up from wake turbulence. (Fortunately he reinflated before impact and was OK.) I am starting to think that Velos are unusually sensitive to this sort of turbulence.

[murps2000 86]

Ahh, disinformation back to haunt me. And it only took 7 years for someone to catch it.

I think you're right about the wake tubulence ceated by an aircraft's wing when flying slowly, and consequently at a higher angle of attack. Which do you think would create more wake turbulence? A parachute in full flight, or in braked flight?

Don't pilots slow their aircraft in turbulence so as not to have any random gusts add to their airspeed or load factor, and thereby possibly create the overstress situation? I never heard that they did it because it made dealing with the turbulence easier. If they could, would they not still want to proceed through the turbulent air mass as quickly as possible?

Still, I think everyone else was right in this thread. The wing does create more turbulence. We can ignore the jumper.

[billvon 2,396]

>Don't pilots slow their aircraft in turbulence so as not to have any random gusts add to
>their airspeed or load factor, and thereby possibly create the overstress situation?

Yes. And while our wings can take a huge amount of positive loading, they are very fragile in negative loading; it doesn't take much in the way of "negative G's" to collapse our wings.

And I agree, if an airplane pilot didn't have to worry about structural failure (and we didn't have to worry about collapses) they might want to speed up to get through it faster. But collapses are pretty nasty.

>Which do you think would create more wake turbulence? A parachute in full flight, or in braked flight?

Good question, actually. Braked flight is slower which would argue for it, but full flight is cleaner, which would argue for it. We're already so "dirty" aerodynamically, though, that I'd suspect that speed plays the bigger role - and thus slower is more wake-y.

[jurgencamps 0]

Is it just possible that there are just much more velo's than any other x braced canopies in the air?

[billvon 2,396]

>Is it just possible that there are just much more velo's than any other x braced
>canopies in the air?

Velocities were a tiny minority of the total canopies on that dive, and in general are in the minority at the DZ's I jump at (Perris, Elsinore, Otay)

[cderham 0]

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>The lead canopy was a Jedei and the trailing canopy was an 84 Velo. It turned the Velo into a dishrag...

We had a similar event at the bigways at Perris today, and it's the third time I've seen a Velo just fold up from wake turbulence. (Fortunately he reinflated before impact and was OK.) I am starting to think that Velos are unusually sensitive to this sort of turbulence.

Have a friend healing from about the same thing on his velo. He ended up in a dive when the whole RH side of his canopy colapsed / dishragged. Very lucky to be alive!! There might be something about a velo that is more acceptable to wake turbulance..... I am not putting them down I love my 2 Velo 111s cant think of jumping anything else.

Chris
It's Jimmy Time!!
http://www.facebook.com/pages/Team-Fast-As-Fuck/6099474213

[stayhigh 2]

Wake goes up and above from the origin.
staying above and behind the leading canopy is the worst spot to be. IMO.
Staying level with lead pilot's body or slightly lower seems to have way less effect than staying slightly high and behind.

As far a the canopy collapse goes, any x-brace seems to resist wake turbulence more than other canopy. But when canopy folds up whether it be due to wake or dust devil or dirty air, they seem to go violently and takes more altitude to recover.

Bernie Sanders for President 2016