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Tuukka

Hitting an airbump in freefall?

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I tend to feel something like this sometimes but I put it down to my pull sequence. I tend to slow fall immediately before pulling to get the speed as low as I can after free flying, but then relax into a big arch and go slightly head high just as I toss the pilot chute. The speed change due to body position is sometimes noticeable just before the opening sequence starts.

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Some experienced jumpers were talking about this the other day. One guy said he got a definite falling sensation mid-dive and it really freaked him out, but it has only ever happened the once.



It could be one of your dearly-departed friends swooping down to dock on you but from being out of practice they dropped onto your back instead.

You never know. It might have happened.
"For you see, an airplane is an airplane. A landing area is a landing area. But a dropzone... a dropzone is the people."

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I feel an increase in speed when I got from boxman to a sit....is this normal? It freaks me out too.



This is crazy! I felt the opposite from head down to box...that,
this can't be coincidence
What goes around, comes later.

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Some experienced jumpers were talking about this the other day. One guy said he got a definite falling sensation mid-dive and it really freaked him out, but it has only ever happened the once.



It could be one of your dearly-departed friends swooping down to dock on you but from being out of practice they dropped onto your back instead.

You never know. It might have happened.



Yeah, that could have happened. But more likely it was because one of your still-here friends went low.

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Was the canopy ride bumpy? I think it's pretty unlikely that there was turbulence you could feel in freefall, but not under canopy.



There was little shaking under canopy but nothing special. Had some scattered clouds but not over the dz directly if I remember right.

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This really might stir up a smile or two (I know ;) ) but has anyone noticed a momentary speed increase in free fall?
Last saturday I was around 3300ft and getting ready to pull in good box position and I swear I suddenly felt this increase in speed. I was alone so it wasn't anyones turbulence. Somebody had a theory that it could have been that I hit a border of ascending and descending air masses.
Any similar experiences? :)



Do not mention such an experience until you screw up a move in a freefall fomation, then use it.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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How close to the Bermuda Triangle do you live, and are you sure that you are still in the same poliverse you exited the plane in? :P



Very close! We usually just holds hands on a plane and wait for it to dissappear! Pop! And we're in freefall allready docked. :P

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How close to the Bermuda Triangle do you live, and are you sure that you are still in the same poliverse you exited the plane in? :P



Very close! We usually just holds hands on a plane and wait for it to dissappear! Pop! And we're in freefall allready docked. :P



Oh! That sounds more like a time dilation/distortion issue. :S
lisa
WSCR 594
FB 1023
CBDB 9

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Do not mention such an experience until you screw up a move in a freefall fomation, then use it.



Hahaa! I try to remember that when I overshoot my slot in a bigway. :)


Using the terms "gravity storm" or the legendary "rarefied air molecules" (search - tandem swooping/surfing) are also great ways to deflect responsibility and get a laugh.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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Do not mention such an experience until you screw up a move in a freefall fomation, then use it.



Hahaa! I try to remember that when I overshoot my slot in a bigway. :)


Using the terms "gravity storm" or the legendary "rarefied air molecules" (search - tandem swooping/surfing) are also great ways to deflect responsibility and get a laugh.



:D I knew that air molecule thing sounded fishy!
...something new everyday

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Could ya pass that this way? :$



Hey man! what if we're just living on an electron in a giant atom! ...and what if atoms are really just tiny solar systems! Got any more cheetos? B|




No but I'll go get some...where did I park?
Wait, did I drive here & who are you??










~ If you choke a Smurf, what color does it turn? ~

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Nah, never felt that. But I have felt an increase in temperature....warm layer I guess.

Maybe you just hit a hole in the earths gravity....

I did experience a strong smell of boiled cabbage one day, but that was under canopy, and as I was flying over the local Rock College, I figured that was what they were having for lunch....
My computer beat me at chess, It was no match for me at kickboxing....

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Could ya pass that this way? :$



Hey man! what if we're just living on an electron in a giant atom! ...and what if atoms are really just tiny solar systems! Got any more cheetos? B|



Unlikely. Laws of physics don't apply in sub-atomic level. B|

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Nah, never felt that. But I have felt an increase in temperature....warm layer I guess.



Could be. I believe it had something do with airpressure and temperature. Was the sudden dropping sensation real or not, it's hard to prove.
Hole in earths gravitational pull would result in slowing down sensation ;)

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The idea of feeling turbulence in freefall is going to be generally discounted, and not something we are usually looking for, but I wouldn't rule the possibility out entirely.

One thing is that with an effectively high wing loading or ballistic coefficient, a skydiver will be affected less by turbulence or wind shear. A light aircraft will feel every bump, a heavier one will be less affected. Wings however are a bit of a different case because they are far more aerodynamically efficient than a blunt body and thus will be more affected by small changes in airflow. For wingsuits, although not all the efficient compared to real wings, I think the BASE guys really notice it if they are in turbulent air.

Turbulence tends to be higher lower down, but one certainly has thermally summer days where in temperate climes one may have cumulus cloud at 3 to 6 thousand feet, so updrafts (and associated shears and downdrafts) are present up to at least that level. While these are generally vertical they aren't perfectly straight columns (within the air mass) so one could hit areas of different airflow during a largely vertical skydive.

The question really becomes, whether say hitting the edge of a 600 fpm thermal boiling off in some direction is going to cause enough acceleration to be noticeable to a skydiver, with a drag coefficient somewhere around 1. One could plug numbers into the basic drag equation to find the drag (Drag = 1/2*rho*V^2*S*Cd), and then with mass calculate acceleration, for some small change in airspeed. But whatever number we come up with, I don't know how noticeable that value is. It will tend to be more noticeable the less other physical activity and body sensations are going on -- better if there is not a lot of body movement, or taking grips on others, or having a flapping loose jumpsuit etc. A slight change in acceleration in an elevator, for example, will be easier to notice if standing perfectly still in the elevator, not moving around and focusing on a conversation.

One may also need for the jumper to be in a region of changed airflow long enough for the acceleration to be noticed -- e.g, half a second's worth of disturbed airflow might not be enough to notice easily.

Although I think all these factors have to be considered, in the end I don't know for sure what the answer is. But I figure that although we're usually not paying attention to subtle things like it, and are usually in relatively smooth air up high, it is quite possible that we would feel turbulence and wind shear in freefall.

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